bluuebunny/crossref_metadata_2025 huggingface dataset:
Counteraction of the Rapid Tolerance to 8‐Hydroxy‐2‐(di‐n‐propylamino)tetralin‐Induced Hypothermia in Rats by Activation of the GABAA Receptor‐Chloride Channel Complex
Authors: Kelder Diana , Ross Svante B.
Published: March 2003

Abstract: The effects of compounds that open the GABAA receptor‐chloride channel complex on the rapidly developed tolerance to the 8‐hydroxy‐2‐(di‐n‐propylamino)tetralin hydrobromide(8‐OH‐DPAT)‐induced hypothermia in rats were examined. The test compound was injected 15 min. before 1 mg/kg subcutaneous 8‐OH‐DPAT or saline and 24 hr later a challenge dose of 0.1 mg/kg subcutaneous 8‐OH‐DPAT was given. The rectal temperature was measured before the challenge dose and 30, 60, 90 and 120 min. thereafter. The hypothermic effect was calculated as the area under the curve. It was found that all the GABAergic compounds examined significantly counteracted the 8‐OH‐DPAT‐induced tolerance to the hypothermic response: muscimol at 3 mg/kg subcutaneous, diazepam at 1 – 3 mg/kg subcutaneous, pentobarbitone sodium at 20 mg/kg subcutaneous, and chlormethiazole at 40 mg/kg subcutaneous. Combined treatment of the rats with the GABAA receptor antagonist, bicucculine, or the GABAA receptor‐chloride channel blocker, picrotoxin and diazepam, pentoparbitone sodium or chlormethiazole significantly antagonised this counteraction of the 8‐OH‐DPAT‐induced tolerance. Depletion of 5‐HT by pretreatment of the rats with the tryptophan hydroxylase inhibitor p‐chlorophenylalanine did not counteract the 8‐OH‐DPAT‐induced tolerance to the hypothermic response. Pretreatment of the rats with dexamethazone did not change the development of the tolerance to 8‐OH‐DPAT‐induced hypothermic effect which seems to exclude the involvement of the hypothalamo‐pituitary‐adrenocortical axis in the tolerance development. It is concluded that the results support the hypothesis that GABA neurones beyond the 5‐HT neurones are involved in the mechanism causing tolerance to the 5‐HT1A receptor‐mediated hypothermia in rats.
Acetaminophen Induces a Caspase‐Dependent and Bcl‐xLSensitive Apoptosis in Human Hepatoma Cells and Lymphocytes
Authors: Boulares A. Hamid , Zoltoski Anna J. , Stoica Bogdan A. , Cuvillier Olivier , Smulson Mark E.
Published: March 2003

Abstract:Acetaminophen is a widely used analgesic and antipyretic drug that exhibits toxicity at high doses to the liver and kidneys. This toxicity has been attributed to cytochrome P‐450‐generated metabolites which covalently modify target proteins. Recently, acetaminophen, in its unmetabolized form, has been shown to affect a variety of cells and tissues, for instance, testicular and lymphoid tissues and lymphocyte cell lines. The effects on cell viability of acetaminophen at a concentration comparable to that achieved in plasma during acetaminophen toxicity have now been examined with a hepatoma cell line SK‐Hep1, primary human peripheral blood lymphocytes and human Jurkat T cells. Acetaminophen reduced cell viability in a time‐dependent manner. Staining of cells with annexin‐V also revealed that acetaminophen induced, after 8 hr of treatment, a loss of the asymmetry of membrane phospholipids, which is an early event associated with apoptosis. Acetaminophen triggered the release of cytochrome c from mitochondria into the cytosol, activation of caspase‐3, 8, and 9, cleavage of poly(ADP‐ribose) polymerase, and degradation of lamin B1and DNA. Whereas cleavage of DNA into internucleosomal fragments was apparent in acetaminophen treated SK‐Hep1 and primary lymphocytes, DNA was only degraded to 50‐kb fragments in treated Jurkat cells. Overexpression of the antiapoptotic protein Bcl‐xLprevented these various apoptotic events induced by acetaminophen in Jurkat cells. Caspase‐8 activation was a postmictochondrial event and occurred in a Fas‐independent manner. These results demonstrate that acetaminophen induces caspases‐dependent apoptosis with mitochondria as a primary target. These results also reiterate the potential role of apoptosis in acetaminophen hepatic and extrahepatic toxicity.
Blockade of Spinal Dopamine D2 Receptors Enhances the Pressor Effect of Intravenous Quinpirole in Normotensive, Conscious Rats
Authors: Lahlou Saad
Published: March 2003

Abstract: The present investigation was undertaken to examine whether in conscious intact rats blockade of spinal dopamine D2 receptors enhances the pressor effect of intravenous quinpirole. In saline‐pretreated rats, intravenous quinpirole (1 mg/kg) induced a significant pressor effect, which reached a maximum (17.71±0.60 mmHg) within the first min. after injection. Pretreatment with intravenous (0.5 mg/kg) or intrathecal (40 μg/rat at T9‐T10) domperidone, a dopamine D2 receptor antagonist that does not cross the blood‐brain barrier, significantly enhanced the maximal pressor response to quinpirole (25.60±1.52 and 24.00±1.72 mmHg, respectively). The pressor effect of quinpirole was also significantly enhanced after combined pretreatment with intravenous and intrathecal domperidone, and its maximum (31.60±2.31 mmHg) was significantly higher than that recorded in animals pretreated with intrathecal or intravenous domperidone alone. Intravenous pretreatment with metoclopramide (5 mg/kg) fully abolished the quinpirole‐induced pressor effect. These results show that in conscious intact rats, blockade of spinal dopamine D2 receptors enhances the pressor response to systemic quinpirole, suggesting that this agonist can decrease blood pressure through a spinal dopaminergic mechanism. Thus, our previous hypothesis that the entire effect of intravenous quinpirole on blood pressure in conscious rats can be composed of a central pressor action, a peripheral sympathoinhibitory depressor effect and also a spinal depressor effect is strongly supported by the present findings.
Aloe Emodin Suppresses Myofibroblastic Differentiation of Rat Hepatic Stellate Cells in Primary Culture
Authors: Woo Sun Wook , Nan Ji‐Xing , Lee Sung Hee , Park Eun‐Jeon , Zhao Yu Zhe , Sohn Dong Hwan
Published: March 2003

Abstract: We have studied the inhibitory effect of aloe emodin on hepatic stellate cells activation and proliferation, as these cells play a key role in the pathogenesis of hepatic fibrosis. Rat hepatic stellate cells were activated by contact with plastic dishes, resulting in their transformation into myofibroblast‐like cells. Primary hepatic stellate cells were exposed to aloe emodin (1–10 μg/ml). Possible cytotoxic effects were measured on stellate cells and hepatocytes using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. The effects of aloe emodin on production of type I collagen and smooth muscle cell α‐actin were examined at the same concentration, by quantitative immunoprecipitation. Antiproliferative effects were examined by bromodeoxyuridine incorporation. Aloe emodin at 10 μg/ml restored the morphological changes characteristic of activated primary stellate cells, reduced DNA synthesis to 95% of control hepatic stellate cells at 10 μg/ml without affecting cell viability, and inhibited type I collagen production and smooth muscle α‐actin expression by 86.77% and 99%, respectively, which suggest that aloe emodin is a potent inhibitor of stellate cell transformation.
Effects of Chronic Citalopram Treatment on Central and Peripheral Spontaneous Open‐Field Behaviours in Rats
Authors: Kugelberg Fredrik C. , Apelqvist Gustav , Bengtsson Finn
Published: March 2003

Abstract: The spontaneous open‐field behavioural effects of 10 days of chronic treatment with two clinical doses (10 and 20 mg/kg daily) and one high/toxic dose (100 mg/kg daily) of the selective serotonin reuptake inhibitor citalopram (delivered subcutaneously by implanted osmotic pumps) were examined in rats. Central and peripheral arena locomotor and rearing activities were recorded simultaneously, and the data were assessed during the first hour as well as during the following 24 hr (the latter for effects on the diurnal rhythm). Rats treated with 100 mg/kg daily exhibited lower peripheral locomotor and rearing activities than the other groups during the first test hour. The ratio between central and peripheral activity increased in a dose‐dependent non‐proportional manner during the first test hour, indicating a general increase in the central arena activity exerted by the rats when treated with citalopram. No major differences were observed between any of the four groups in overall behavioural activities over the 24‐hr period. This study indicated that the open‐field locomotor and rearing behaviours in normal rats were affected by increasing doses of racemic citalopram, particularly during the first hour of adaptation.
Pien Tze Huang Protects the Liver against Carbon Tetrachloride‐Induced Damage
Authors: Lee Kenneth K. H. , Kwong Wing Hang , Chau Foo‐tim , Yew David T. , Chan Wood Yee
Published: March 2003

Abstract: Pien Tze Huang, a traditional Chinese medicine, has been extensively used as a therapeutic drug in the treatment of liver diseases. In this study, we have examined its ability to protect the liver from carbon tetrachloride (CCl4)‐induced damage in the mouse. Histological observations revealed that CCl4 treatment induced extensive degenerative changes in the hepatocytes surrounding the central veins of the liver. However, these changes were much reduced by more than 28% in mice fed with 0.5 mg of Pien Tze Huang/g body weight/dose (3 doses over 36 hr) prior to CCl4 treatment. The effects of Pien Tze Huang were then further investigated in a hepatoma cell line. Flow analysis showed that it had no significant effects on cell proliferation. When the ability of Pien Tze Huang to influence various response elements of important signal transduction pathways was examined in the hepatoma cell line, it was found that Pien Tze Huang stimulated an increase in the response of AP1, CRE and NFκB responsive elements. The transcriptional factors of these responsive elements are known to play important roles in regulating cell death and survival. We thus postulate that the ability of Pien Tze Huang to protect the liver from damage is attained through its ability to modulate the activity of these important signal transduction pathways.
Applications of Fluorescence in the Characterization of the Ligand‐Binding Domain and Activation of the Cholecystokinin Receptor
Authors: Harikumar Kaleeckal G. , Miller Laurence J.
Published: March 2003

Abstract: Fluorescence techniques can be applied to guanine nucleotide‐binding protein‐coupled receptors to gain insights into the environment and molecular motion of a fluorophore that is either incorporated into a ligand or more directly into a specific site within the receptor. Fluorescence studies can provide insight into the environment of that indicator. By situating the same indicator into an analogous position in both agonist and antagonist ligands, comparisons can provide insights into differences between active and inactive states of the receptor. These types of studies have been performed for the cholecystokinin receptor and show that receptor activation by agonist occupation is associated with a movement of the CCK‐like ligand out of a protected environment and into a more accessible hydrophilic milieu.
UVB‐induced GM‐CSF production is suppressed by dexamethasone in HaCaT Cells
Authors: Kim Dong Seok , Kim Hye Jin , Choi Kyoung Hee , Chung Jin‐Ho , Kim Kyu Han , Park Kyoung Chan
Published: March 2003

Background: Epidermal keratinocytes are important sources of a wide variety of cytokines that include the Granulocyte‐macrophage Colony Stimulating Factor (GM‐CSF). Glucocorticoids have been shown to inhibit the production of several cytokines. However, their effect on GM‐CSF synthesis by keratinocytes is still unknown.

Methods: The effects of glucocorticoid on GM‐CSF production by keratinocytes were evaluated using ELISA and RT‐PCR analysis.

Results: GM‐CSF secretion by HaCaT cells increased with increasing UVB exposure. Dexamethasone suppressed basal release of GM‐CSF. In addition, it strongly inhibited both the UVB‐mediated augmentation of GM‐CSF protein production and mRNA expression. Lincomycin enhanced slightly the inhibitory effect of dexamethasone on GM‐CSF synthesis, while lincomycin itself had no effect on GM‐CSF secretion.

Conclusion: Results showed that dexamethasone suppressed basal release and UVB‐induced production of GM‐CSF by keratinocytes.
Does the minimal phototoxic dose after 8‐methoxypsoralen baths correlate with the individual’s skin phototype?
Authors: Schiener Ralf , Behrens‐Williams Stefanie C. , Pillekamp Hans , Peter Ralf Uwe , Kerscher Martina
Published: March 2003

Background/Aims: Up to now no data have been available concerning whether there is a significant correlation between skin phototypes and the minimum phototoxic dose (MPD) after bath water delivery of 8‐MOP.

Methods: The skin phototype of each of 46 patients was determined based on the individual past history of solar‐induced burning and tanning. In addition, the MPD of each patient was assesed after photosensitization with a warm water bath (37 °C, 98.6 °F) containing 1.0 mg/l 8‐methoxypsoralen (8‐MOP). Statistical analysis was performed using a Mann‐Whitney U‐test and Spearman rank order correlation.

Results: The median MPD in patients with skin phototype II was 2.0 J/cm2 (range ≤0.5 to ≥3.5) versus 1.5 J/cm2 (range 1.0 to ≥3.5) in patients with skin phototype III. There was a considerable overlap between both groups. No significant difference was detected comparing both groups (P=0.7326) and Spearman rank order correlation revealed no correlation between skin phototype and MPD.

Conclusion: Erythemal sensitivity in PUVA bath therapy, measured as MPD, is not correlated with sun‐reactive skin phototype in skin types II and III. Thus skin phototype is not a suitable indicator for the initial UVA dose in PUVA bath photochemotherapy.
Extracorporeal photochemotherapy – the Columbia Presbyterian experience
Authors: Knobler Elizabeth , Warmuth Ingrid , Cocco Carolyn , Miller Barbara , Mackay Julian
Published: March 2003

Background:Cutaneous T Cell Lymphoma (CTCL) is a lymphoma of skin homing usually CD4  +  lymphocytes. There are numerous treatments available both for the early as well as the more advanced stages of the disease. Extracorporeal photochemotherapy is a well‐accepted form of treating CTCL. The purpose of our study was to review the experience of treating 20 CTCL patients with extracorporeal photochemotherapy (ECP) at Columbia Presbyterian Medical Center over a seven‐year period.

Methods:The study was conducted as a retrospective chart review of these 20 patients. Summarized demographic characteristics included age at diagnosis, gender, and race. We analyzed the overall response by categorizing patients as having complete response, partial response, stable disease, and progressive disease. We also analysed the predictive value for three factors: peripheral blood CD4 : CD8 (< 10, > 10), LDH level (normal, elevated), and erythrodermic status (erythrodermic or nonerythrodermic). The potential prognostic variables were evaluated for linear association with response using Mantel‐Haenszel chi‐square tests. All statistical tests were two‐sided with alpha = 0.05. The tests were considered to be exploratory and no adjustments for multiple testing were made.

Results:There was a significant linear association between response and CD4 : CD8. Patients with a ratio< 10 were more likely to respond than patients with a ratio> 10. There was a marginally significant linear association between response and LDH level. Patients whose LDH was not elevated at the start of treatment, tended to have a better response to ECP compared to patients with an elevated LDH. There was a suggestion of an association between erythroderma and response although this was not statistically significant. The majority of patients with erythroderma were responders compared to the majority of non‐erythrodermic patients who were non‐responders. The treatment was well tolerated with minimal side‐effects.

Conclusion:Apparent predictors of good response to ECP include erythroderma, a relatively low (closer to normal) peripheral CD4 : CD8, and a normal LDH. This report confirms reports from other institutions indicating that CTCL patients who are erythrodermic with a relatively intact immune system are optimal candidates for ECP.
011 Polymorphous light eruption (PMLE) in African‐Americans presenting as pinpoint papules
Authors: Kontos A. , Cusack C. , Lim H.W.
Published: March 2003

Polymorphous light eruption (PMLE) is the most common chronic idiopathic photodermatosis with a prevalence estimated at 10‐20% and a genetic predisposition from 5‐45%. It tends to occur in the spring with gradual resolution as summer progresses. Papular eruptions are most commonly seen, however, several morphological variants exist among affected individuals, including vesicular, eczematous and papulovesicular lesions. Lesions are usually monomorphic in a given patient. We present nine African‐American female patients in whom PMLE manifests as a pinpoint papular variant, which has not been commonly described previously. Of the four patients who were phototested, one had an abnormal UVA MED result of 12 J/cm2. Histopathologic findings revealed perivascular and focal lichenoid lymphohistiocytic infiltrate with papillary dermal hemorrhage in all biopsy specimens.
006 Efficacy of photochemotherapy and UVA‐1 therapy in patients with morphea or lichen sclerosus
Authors: Ghoreschi K. , Röcken M.
Published: March 2003

Morphea and lichen sclerosus are inflammatory skin diseases of unknown aetiology. Morphea can be subdivided into plaque morphea, linear morphea and disabling or generalized morphea. In most patients morphea leads to superficial or deep sclerosis of the skin. The characteristic features of lichen sclerosus which often affects the genital area are edema of upper dermis, inflammatory infiltration and hyalinisation to the dermis at advanced stages. Patients with morphea or lichen sclerosus suffer especially from scar formation and morphea may lead to severe disfigurement, contractures and reduction of quality of life. Skin sclerosis seems to be the result of vascular damage, T cell activation and altered connective tissue production. Various therapies have been reported for lichen sclerosus and morphea. Whereas the topical use of ultrapotent corticosteroids is well established for genital lichen sclerosus, immunosuppressive agents are normally not successful in resolving extragenital skin sclerosis. In a retrospective study we confirmed the efficacy of phototherapy in more than 50 patients with morphea. Fourty treatments with 30 J/cm2 UVA‐1 or PUVA‐bath photochemotherapy resulted in a significant improvement, reduced skin thickness, as determined by high frequency ultrasound and reconstitution of functional mobility of the skin and even the underlying fasciae. In lichen sclerosus phototherapy was successful only in some patients. Thus for lichen sclerosus the use of topical corticosteroids is the first choice therapy, while phototherapy using either PUVA‐bath or medium dose UVA‐1 are the most effective treatments for morphea.
Physiological concentrations of melatonin and corticosterone affect phagocytosis and oxidative metabolism of ring dove heterophils
Authors: Rodríguez A.B. , Terrón M.P. , Durán J. , Ortega E. , Barriga C.
Published: March 2003

A functional connection between the neuroendocrine and the immune systems has been established. Of particular interest is the finding that hormones such as melatonin and corticosterone are able to exert modulating effects on the immune function. Therefore, after determining the circadian rhythms of melatonin and corticosterone, we evaluated the in vitro effect of physiological concentrations of melatonin and corticosterone, separately and together, on the phagocytic function and superoxide anion levels of heterophils in ring dove (Streptopelia risoria). Trials were performed with concentrations corresponding to the nocturnal and diurnal levels reached by each of the hormones (50:300 pg/mL and 100:10 ng/mL for melatonin and corticosterone, diurnal:nocturnal, respectively). The phagocytes were incubated with the hormones both alone and concurrently. At the highest (nocturnal) concentration, melatonin augmented phagocytic function and at the same time inducing a fall in superoxide anion levels. At the highest (diurnal) concentration, corticosterone also enhanced phagocytic function, but without modifying the phagocyte oxidative metabolism. In the presence of both hormones, however, whether with nocturnal or diurnal concentrations, there was a greater increase in phagocytic function and a decrease in superoxide anion levels than was produced by either of the hormones alone. In conclusion, our findings suggest that melatonin and corticosterone may have an additive effect in the modulation of phagocytic function.
Melatonin protects against oxidative mitochondrial damage induced in rat placenta by ischemia and reperfusion
Authors: Okatani Y. , Wakatsuki A. , Shinohara K. , Taniguchi K. , Fukaya T.
Published: March 2003

We assessed the effects of melatonin, a powerful scavenger of oxygen free radicals, on ischemia/reperfusion‐induced oxidative damage to mitochondria in the rat placenta. In Wistar rats at day 19 of pregnancy, feto‐placental ischemia was induced by occluding both utero‐ovarian arteries for 20 min. Reperfusion was achieved by releasing the occlusion and restoring circulation for 30 min. Melatonin solution or the vehicle alone was injected intraperitoneally at dose of 10 mg/kg 1 hr before occlusion. Sham‐ischemic animals were treated with vehicle. Each group consisted of 10 pregnant rats. We measured placental mitochondrial respiratory control index (RCI; a marker of mitochondrial respiratory activity), the ratio of the added adenosine 5‐diphosphate (ADP) concentration to consumption of oxygen during state 3 respiration (ADP/O), and the concentration of thiobarbituric acid reactive substances (TBARS) in each group. RCI and ADP/O were significantly decreased by ischemia/reperfusion, while TBARS were increased. Melatonin prevented these changes. These results indicate that exogenous melatonin protects against ischemia/reperfusion‐induced oxidative damage to mitochondria in rat placenta. Melatonin could be useful in treating preeclampsia and possibly other clinical states involving excess free radical production, such as fetal growth restriction and fetal hypoxia.
Glutamate induces oxidative stress not mediated by glutamate receptors or cystine transporters: protective effect of melatonin and other antioxidants
Authors: Herrera Federico , Sainz Rosa María , Mayo Juan Carlos , Martín Vanesa , Antolín Isaac , Rodriguez Carmen
Published: March 2003

Glutamate is responsible for most of the excitatory synaptic activity and oxidative stress induction in the mammalian brain. This amino acid is increased in the substantia nigra in parkinsonism due to the lack of dopamine restraint to the subthalamic nucleus. Parkinson's disease also shows an increase of iron levels in the substantia nigra and a decrease of glutathione, the antioxidant responsible for the ascorbate radical recycling. Considered together, these facts could make the antioxidant ascorbate behave as a pro‐oxidant in parkinsonism. Since both glutamate and ascorbate are present in the synaptosomes and neurons of substantia nigra, we tested 1) if glutamate is able to induce oxidative stress independently of its excitatory activity, and 2) if ascorbate may have synergistic effects with glutamate when these two molecules co‐exist. Brains were homogenized in order to disrupt membranes and render membrane receptors and intracellular signaling pathways non‐functional. In these homogenates glutamate induced lipid peroxidation, indicating that this amino acid also may cause oxidative stress not mediated by its binding to glutamate receptors or cystine transporters. Ascorbate also induced lipid peroxidation thus behaving as a pro‐oxidant. Both substances together produced an additive effect but they did not synergize. Given that melatonin is a potent physiological antioxidant with protective effects in models of neurotoxicity, we tested the role of this secretory product on the pro‐oxidant effect of both compounds given separately or in combination. We also checked the protective ability of several other antioxidants. Pharmacological doses of melatonin (millimolar), estrogens, pinoline and trolox (micromolar) prevented the oxidant effect of glutamate, ascorbate, and the combination of both substances. Potential therapeutic application of these results is discussed.
The effects of prior light history on the suppression of melatonin by light in humans
Authors: Hébert Marc , Martin Stacia K. , Lee Clara , Eastman Charmane I.
Published: March 2003

Abstract: We investigated the impact of light exposure history on light sensitivity in humans, as assessed by the magnitude of the suppression of melatonin secretion by nocturnal light. The hypothesis was that following a week of increased daytime bright‐light exposure, subjects would become less sensitive to light, and that after a week of restriction to dimmer light they would become more sensitive. During the bright week, subjects (n = 12) obtained 4.3 ± 0.4 hr of bright light per day (by going outside and using light boxes indoors). During the dim week, they wore dark goggles (about 2% light transmission) when outside during daylight and spent 1.4 ± 0.9 hr per day outside. Saliva samples were obtained every 30 min for 7 hr in dim light (<15 lux) on two consecutive nights (baseline and test night) at the end of each week. On the test night, 500 lux was presented for 3 hr in the middle of the collection period to suppress melatonin. There was significantly more suppression after the dim week compared with after the bright week (to 53 versus 41% of the baseline night values, P < 0.05). However, there were large individual differences, and the difference between the bright and dim weeks was most pronounced in seven of the 12 subjects. Possible reasons for these individual differences are discussed, including the possibility that 1 wk was not long enough to change light sensitivity in some subjects. In conclusion, this study suggests that the circadian system's sensitivity to light can be affected by a recent change in light history.
Melatonin related compounds inhibit lipid peroxidation during copper or free radical‐induced LDL oxidation
Authors: Bonnefont‐Rousselot Dominique , Chevé Gwénaël , Gozzo Andrea , Tailleux Anne , Guilloz Virginie , Caisey Stéphanie , Teissier Elisabeth , Fruchart Jean‐Charles , Delattre Jacques , Jore Daniel , Lesieur Daniel , Duriez Patrick , Gardès‐Albert Monique
Published: March 2003

Abstract:  This study was designed to evaluate the protective effect of two melatonin related compounds towards low density lipoproteins (LDL) oxidation initiated in vitro either by defined free radicals [i.e. superoxide anion (O2·–) and ethanol‐derived peroxyl radicals (RO2·)] produced by gamma radiolysis or by copper ions. The compounds studied were N‐[2‐(5‐methoxy‐1H‐indol‐3‐yl)ethyl]‐3,5‐di‐tert‐butyl‐4‐hydroxybenzamide (DTBHB) and (R,S)‐1‐(3‐methoxyphenyl)‐2‐propyl‐1,2,3,4‐tetrahydro‐β‐carboline (GWC20) which is a pinoline derivative. Their effects were compared with those of melatonin at the same concentration (100 μmol/L). None of the three tested compounds protected endogenous LDL α‐tocopherol from oxidation by RO2·/O2·– free radicals. By contrast, they all protected β‐carotene from the attack of these free radicals with GWC20 being the strongest protector. Moreover, melatonin and DTBHB partially inhibited the formation of products derived from lipid peroxidation (conjugated dienes and thiobarbituric acid‐reactive substances or TBARS) while GWC20 totally abolished this production. As previously shown, melatonin (at the concentration used) inhibited copper‐induced LDL oxidation by increasing 1.60‐fold the lag phase duration of conjugated diene formation over the 8 hr of the experimental procedure, however, DTBHB and GWC20 were much more effective, because they totally prevented the initiation of the propagation phase of LDL oxidation. It would be interesting to test in vivo if DTBHB and GWC20 which exhibit a strong capacity to inhibit in vitro LDL oxidation would reduce or not atherosclerosis in animals susceptible to this pathology.
Does melatonin induce apoptosis in MCF‐7 human breast cancer cells in vitro?
Authors: Cos Samuel , Mediavilla Maria Dolores , Fernández Rosario , González‐Lamuño Domingo , Sánchez‐Barceló Emilio J.
Published: March 2003

Melatonin inhibits proliferation of the estrogen‐responsive MCF‐7 human breast cancer cells. The objective of this work was to assess whether melatonin not only regulates MCF‐7 cell proliferation but also induces apoptosis. In this experiment we used 1,25‐dihydroxycholecalciferol (D3) as a positive control because it inhibits MCF‐7 cell proliferation and induces apoptosis. MCF‐7 cells were cultured with either 1 nM melatonin, 100 nM D3 or its diluent to determine their effects on cell proliferation, cell viability, cell‐cycle phase distribution, population of apoptotic cells, and expression of p53, p21WAF1, bcl‐2, bcl‐XL and bax proteins. After 24 or 48 hr of incubation, both melatonin and D3‐treatment significantly decreased the number of viable cells in relation to the controls, although no differences in cell viability were observed between the treatments. The incidence of apoptosis, measured as the population of cells falling in the sub‐G1 region of the DNA histogram, or by the TUNEL reaction, was similar in melatonin‐treated and control cells whereas, as expected, apoptosis was higher among cells treated with D3 than in controls. The expression of p53 and p21WAF1 proteins significantly increased after 24 or 48 hr of incubation with either melatonin or D3. No significant changes in bcl‐2, bcl‐XL and bax mRNAs were detected after treatment with melatonin whereas in D3‐treated cells, a significant drop in bcl‐XL was observed. These data support the hypothesis that melatonin reduces MCF‐7 cell proliferation by modulating cell‐cycle length through the control of the p53–p21 pathway, but without clearly inducing apoptosis.
Melatonin and its derivatives cyclic 3‐hydroxymelatonin, N1‐acetyl‐N2‐formyl‐5‐methoxykynuramine and 6‐methoxymelatonin reduce oxidative DNA damage induced by Fenton reagents
Authors: López‐Burillo Silvia , Tan Dun‐Xian , Rodriguez‐Gallego Vergelina , Manchester Lucien C. , Mayo Juan Carlos , Sainz Rosa Maria , Reiter Russel J.
Published: March 2003

Abstract:  Free radicals are generated in vivo and they oxidatively damage DNA because of their high reactivities. In the last several years, hundreds of publications have confirmed that melatonin is a potent endogenous free radical scavenger. Some of the metabolites produced as a result of these scavenging actions have been identified using pure chemical systems. This is the case with both N1‐acetyl‐N2‐formyl‐5‐methoxykynuramine (AFMK), identified as a product of the scavenging reaction of H2O2 by melatonin, and cyclic 3‐hydroxymelatonin (C‐3‐OHM) which results when melatonin detoxifies two hydroxyl radicals (ḃOH). In the present in vitro study, we investigated the potential of two different derivatives of melatonin to scavenger free radicals. One of these derivatives is C‐3‐OHM, while the other is 6‐methoxymelatonin (6‐MthM). We also examined the effect of two solvents, i.e., methanol and acetonitrile, in this model system. As an endpoint, using high‐performance liquid chromatography we measured the formation of 8‐hydroxy‐2′‐deoxyguanosine (8‐OH‐dG) in purified calf thymus DNA treated with the Fenton reagents, chromium(III) [Cr(III)] plus H2O2, in the presence and in the absence of these molecules. The 8‐OH‐dG is considered a biomarker of oxidative DNA damage. Increasing concentrations of Cr(III) (as CrCl3) and H2O2 was earlier found to induce progressively greater levels of 8‐OH‐dG in isolated calf thymus DNA because of the generation of ḃOH via the Fenton‐type reaction. We found that C‐3‐OHM reduces ḃOH‐mediated damage in a dose‐dependent manner, with an IC50 = 5.0 ± 0.2 μm; melatonin has an IC50 = 3.6 ± 0.1 μm. These values differ statistically significantly with P < 0.05. In these studies, AFMK had an IC50 = 17.8 ± 0.7 μm (P < 0.01). The 6‐MthM also reduced DNA damage in a dose‐dependent manner, with an IC50 = 4.2 ± 0.2 μm; this value does not differ from the ICs for melatonin and C‐3‐OHM. We propose a hypothetical reaction pathway in which a mole of C‐3‐OHM scavenges 2 mol of ḃOH yielding AFMK as a final product. As AFMK is also a free radical scavenger, the action of melatonin as a free radical scavenger is a sequence of scavenging reactions in which the products are themselves scavengers, resulting in a cascade of protective reactions.
Alterations in the circadian rhythm of salivary melatonin begin during middle‐age
Authors: Zhou Jiang‐Ning , Liu Rong‐Yu , van Heerikhuize Joop , Hofman Michel A. , Swaab Dick F.
Published: March 2003

Abstract: To investigate whether free melatonin may be better suited to reveal age‐related changes, we studied the circadian rhythm alterations in saliva melatonin levels during aging. Special attention was paid to the question as to how the free melatonin rhythms change in aging and when such changes take place. A total of 52 healthy volunteers participated in the study consisting of young, middle‐aged, old and the oldest groups. In each subject, a total of 12 time‐point salivary melatonin samples was taken over 24 hr. Of the 52 data sets, 51 exhibited significant circadian rhythm over 24 hr by using the base cosine function analysis to fit the data. A clear circadian rhythm of salivary melatonin was present in all age groups. The decline in nocturnal peak levels (amplitude) in salivary melatonin was found in old and the oldest subjects. Both the old and the oldest subjects showed an increased daytime (baseline) melatonin levels. The off‐set melatonin levels were more than two times higher in the oldest group than that in the other groups indicating a delayed phase of salivary melatonin. Most strikingly, we found that a step‐wise decrease in the circadian rhythms of saliva melatonin occurred early in life, around 40 yr of ages. The middle‐aged subjects had only 60% of the amplitude of the young subjects. In addition, the middle‐aged subjects showed the longest peak levels duration and the lowest daytime melatonin levels. The present study showed that the alterations in the circadian rhythms of salivary melatonin begin during middle‐age. Our results showed that salivary melatonin measurement is a reliable, sensitive and easy method to monitor changes in the circadian rhythms of melatonin during the course of aging.
Hematological indices in elite cyclists
Authors: Schumacher Y. O , Jankovits R , Bültermann D , Schmid A , Berg A
Published: March 2003

Background: Blood testing is a major concern in sports. Sporting federations have introduced cut‐off values for hematological variables to limit blood manipulations. Do date, no reference margins have been established to adjust single‐ or multivariable blood tests to the exercise adapted blood cell system of athletes. We studied hemoglobin (Hb), hematocrit (Hct), blood cell variables and changes in vascular volumes in male and female national team cyclists to evaluate the influence of exercise on these variables and the results of blood tests, and to estimate normal ranges in athletes for blood tests.Methods: 1628 blood samples of 169 male and 55 female athletes were considered. Samples were analyzed automatically, blood cell indices and vascular volumes were calculated. Overall averages and seasonal differences were estimated.Results: Hb‐average was: 15.4 ± 0.8 g dL−1for male and 13.9 ± 0.7 g dL−1for female cyclists, Hct: 45 ± 2.9% and 40.7 ± 2.7%. Blood variables and vascular volumes showed significant seasonal changes. 1–6% of all samples were found above the currently used limits for blood testing. This is in accordance with the data from the normal population. Nevertheless, EPO misuse or blood manipulations cannot totally be excluded.Conclusion: Athletes display seasonal adaptations in their blood profile which should be considered in testing regulations. The presented data might be used as reference values for indirect single‐ and multivariable blood tests.
Ageing and local growth factors in muscle
Authors: Harridge Stephen D. R.
Published: March 2003

Muscle responds to mechanical overload by increasing its size. In contrast, as a muscle gets older it atrophies. The mechanisms regulating these differing responses are not fully understood. Animal studies have shown that older muscles are less well able to repair following contraction‐induced injury than young muscles. It is becoming clear that local growth factors produced within the muscle may play important roles in both repair, adaptation and ageing. The growth hormone/insulin like growth factor 1 (GH/IGF‐I) axis is important during growth and development, but circulating levels of these hormones decline in later life. However, many tissues including muscle, produce IGF‐I for autocrine and paracrine actions. Genetic manipulation of IGF‐I in muscle has shown that it has considerable anabolic affects on muscle both in young and old animals. Insulin like growth factor 1 exists in multiple isoforms and one isoform, which differs from the systemic or liver type (IGF‐IEa), appears to be particularly sensitive to mechanical signals and to muscle damage. This isoform (IGF‐IEc) has been termed mechano growth factor (MGF). The anabolic actions of IGF‐I and MGF are through stimulating protein synthesis and by playing a role in the activation, proliferation and differentiation of satellite cells. These effects are discussed in relation to human studies of muscle adaptation to strength training in older people who seem to retain an ability to increase muscle mass and strength through this type of exercise.
Characterisation of gravity‐induced facial skin oedema using biophysical measurement techniques
Authors: Diridollou S. , Traon A. Pavy‐Le , Maillet A. , Bellossi F. , Black D. , Patat F. , Lagarde J. M. , Berson M. , Gall Y.
Published: March 2003

Background/aims: In humans, the microgravity environment can be expected to induce swelling of facial tissues and shrinking of the tissues in the lower limbs, together with a loss in body weight. To evaluate fluid shifts in skin, the head‐down bed‐rest model was used. The aim of the present study was to evaluate the appearance of facial oedema in subjects undergoing anti‐orthostatic bed‐rest at an angle of −10°.

Methods: The forehead of each of four subjects was measured before and after 1, 10 and 24 h in this head‐down tilt position. At these time points, interstitial fluid migration and facial oedema were assessed using a high resolution B‐scan ultrasound and a device for measuring the skin's mechanical properties.

Results: The results obtained showed a progressive increase in dermal thickness and initial stress, and a reduction in stiffness and elasticity of the skin during the study period.

Conclusions: This preliminary study has demonstrated the feasability of the method in measuring fluid displacement and retention in the skin. Furthermore, it highlights the influence of fluids on the mechanical behaviour of the skin. These techniques could be used for studying the redistribution of liquid masses during periods spent in space.
Development of a digital imaging system for objective measurement of hyperpigmented spots on the face
Authors: Miyamoto Kukizo , Takiwaki Hirotsugu , Hillebrand Greg G. , Arase Seiji
Published: March 2003

Background/aims: There are few available methods that can be used to quantify hyperpigmented spots on a wide area of the face. The objective of this study was to develop such a method through the use of specialized image analysis technologies.

Methods: This imaging system was composed of a source of illumination whose light intensity was controlled with a dimmer, a 3‐CCD video camera connected to a computer, and a positioning device used to correctly align the subject's face. This system was calibrated by adjusting the light intensity, the camera position, and white balance of the camera in order to acquire reproducible images. Using a specific algorithm for the image analysis, this system enabled us to measure both the total area of hyperpigmented spots (mm2) and the averaged skin colour tone (quasi L*a*b*) excluding the area of those hyperpigmented spots in a wide area of the face. The accuracy and reproducibility of the system was validated using a mannequin head with six standard colour chips obtained from the GretagMacbeth ColorChecker®, and brown‐coloured patches that simulated hyperpigmented spots whose colour and area were both known. The correlation between CIE L*a*b* and quasi L*a*b* values was examined by conducting simultaneous measurements of the facial skin colour of 187 subjects with a tristimulus colourimeter (Minolta Chromameter) and our imaging system.

Results: The measurement errors in quasi L*a*b* values of colour chips and the area of brown patches were less than 2 and 5%, respectively, unless these chips or patches were located in the peripheral zone of the mannequin head. The variation in quasi L*a*b* values and the area of hyperpigmented spots (mm2) in five repeated measurements performed once every hour was less than 2%. There was an excellent correlation between the CIE L*a*b* and quasi L*a*b* values, and the Pearson's correlation coefficient between CIE L* and quasi L* value, for instance, was 0.908.

Conclusions: As long as the region to be evaluated is limited to the cheek and periorbital areas, this system enables automatic detection of hyperpigmented spots in a wide area of the face, as well as the correct measurement of those areas and determination of skin colours.
The character of eyelashes and the choice of mascara in Korean women
Authors: Kwak Taek‐jong , Lee Sang‐min , Cho Wan‐gu
Published: March 2003

Background/aims Skin care products based on the skin type and sensitivity have been successfully appealed in cosmetics market, but there has been few researches related with the character of customer in the field of make‐up product including mascara. The aim of this study is to analyse and classify the eyelashes of Korean women objectively and to find out the relationship between individual eyelash character and expecting mascara‐effect.

Methods For 50 Korean women in their twenties to thirties, 12 parameters related to shape of eyelashes were investigated using image analysis system with digital camera. The experimental data were compared with the subjects' perception and questionnaire to determine the tendency of mascara was performed on same panels. Subjects were classified and the relation between the shape of eyelashes and need for mascara was investigated by statistical procedure.

Results Average length of centre section (ALCS), covering ratio (CR) and curl‐up angle (CA) were the numerical parameters that can represent the length, thickness and curling of subjects' eyelashes, respectively. Subjects were classified into 6 clusters (I∼VI) by the similarity of above three parameters using cluster analysis method. Cluster I∼III were characterized as the short and thin eyelashes with a preference for long‐lash effect and complaint about staining of lower‐eyelid in the use of mascara. Cluster IV∼VI had the long and thick eyelashes with preference for volume‐up effect of mascara and complaint about cleaving of eyelashes. Subjects had five sorts of preference patterns about mascara‐effects and those patterns were highly related with the shape of their eyelashes.

Conclusion Image analysis system and statistical procedure were the useful methods in characterizing the shape of eyelash and finding the objective criteria for classification of eyelashes. Because shape of eyelash turned out to be one of the most important factors that can influence the need and complaint of subjects about mascara in this study, the consideration of shape of eyelashes is recommended in the development of mascara which can satisfy the customers' demand.
Role of Membrane Organization and Membrane Domains in Endocytic Lipid Trafficking
Authors: Mukherjee Sushmita , Maxfield Frederick R.
Published: March 2003

Lipid compositions vary greatly among organelles, and specific sorting mechanisms are required to establish and maintain these distinct compositions. In this review, we discuss how the biophysical properties of the membrane bilayer and the chemistry of individual lipid molecules play a role in the intracellular trafficking of the lipids themselves, as well as influencing the trafficking of transmembrane proteins. The large diversity of lipid head groups and acyl chains lead to a variety of weak interactions, such as ionic and hydrogen bonding at the lipid/water interfacial region, hydrophobic interactions, and van‐der‐Waals interactions based on packing density. In simple model bilayers, these weak interactions can lead to large‐scale phase separations, but in more complex mixtures, which mimic cell membranes, such phase separations are not observed. Nevertheless, there is growing evidence that domains (i.e., localized regions with non‐random lipid compositions) exist in biological membranes, and it is likely that the formation of these domains are based on interactions similar to those that lead to phase separations in model systems. Sorting of lipids appears to be based in part on the inclusion or exclusion of certain types of lipids in vesicles or tubules as they bud from membrane organelles.
Periodontal disease in primary Sjögren's syndrome
Authors: Schiødt M , Christensen LB , Petersen PE , Thorn JJ
Published: March 2003

Occurrence of periodontal disease in Sjögrens's syndrome (SS) is still controversial.

OBJECTIVE: To examine if the risk of gingival and periodontal conditions was increased in SS compared to the general population.

MATERIALS AND METHODS: Fifty‐seven patients (4 men, 53 women) with primary Sjögren's syndrome (Copenhagen criteria) and an age‐matched representative sample of the general population of 80 controls (all women) were examined for gingival and periodontal disease.

RESULTS: Gingival bleeding and supra‐gingival calculus did not differ among SS patients and controls. Subgingival calculus occurred more often among the younger SS patients than controls, but did not differ among the older SS patients and controls. Periodontal pockets of 4–5 mm as well as pockets >5 mm occurred with similar prevalences among the two groups. Smoking habits did not influence the results. The health status of the gingival and periodontal tissues were thus similar in SS and controls.

CONCLUSION: Primary SS is not associated with increased risk of periodontal disease.
The HIV‐1 epidemic in South Africa
Authors: Puren AJ
Published: March 2003

The first reported cases of HIV‐1 infection in South Africa occurred in 1982. Two distinct HIV‐1 epidemic patterns were recognized. Initially the infection was prevalent in white males who had sex with males. The HIV‐1 clade B was associated with this group. By 1989, the second epidemic was recognized primarily in the black population. Infections in this case were mainly heterosexual in origin. The HIV‐1 clade involved was mainly C. The national HIV‐1 sero‐prevalence in antenatal attendees was less than 1% in 1990 and by 1994 this figure had risen to 7.5%. The most recent antenatal surveillance for HIV‐1 sero‐prevalence in 1999 revealed the following. The national prevalence rate for 1999 was 22.4% compared with the 1998 rate of 22.8%. The data highlighted the profound effect the epidemic had and will have on the disease burden in South Africa and by extension on the social and economic fronts. This view was emphasised by the impact HIV‐1 infection had on tuberculosis. For example, sentinel surveys have attributed 44% of tuberculosis cases to HIV‐1 infection. Moreover, the high prevalence of sexually transmitted infections will certainly exacerbate the HIV‐1 epidemic.