bluuebunny/crossref_metadata_2025 huggingface dataset:
Pharmacodynamic Response of Entacapone in Rats after Administration of Entacapone Formulations and Prodrugs with Varying Bioavailabilities
Authors: Forsberg Markus , Savolainen Jouko , Järvinen Tomi , Leppänen Jukka , Gynther Jukka , Männistö Pekka T.
Published: March 2003

Abstract: The aim of this in vivo study was to assess the effect of improved oral bioavailability of entacapone on its actual pharmacodynamic response, COMT inhibition in erythrocytes. Rats were administered entacapone orally as a suspension, as a plain solution, an entacapone/HP‐β‐CD solution, two N‐alkyl‐carbamate ester prodrugs and intravenously as a solution. Also the relationship between pharmacodynamic and pharmacokinetic responses of entacapone was investigated. The administration of entacapone as a solution (plain solution pH 7.4; F=34.8% or entacapone/HP‐β‐CD solution pH 3.0; F=18.5%) resulted in significantly higher degree of COMT inhibition in erythrocytes than could be achieved by administering entacapone as a suspension (pH 3.0; F=8.9%). The inhibitory Emax model did not reveal any significant differences in EC50 estimates of entacapone suspension, entacapone/HP‐β‐CD solution or entacapone solution. The overall pharmacodynamic response of entacapone (AUE; area under effect‐time curve) was dependent on the pharmacokinetic response (AUC; area under concentration‐time curve) irrespective of the entacapone formulation and dosage form. However, this dependency did not extend to formulations producing very high peak concentrations of entacapone in plasma; high plasma concentrations reached transiently after administration of entacapone solution had only a minor effect on the overall pharmacodynamic response (AUE). The inhibitory Emax model revealed that a plateau of COMT inhibition near to Emax is attained by plasma concentrations under 2000 ng/ml, irrespective of the formulation. This supports the results concerning the dependence of AUE on AUC.
Nitric Oxide Synthase/Guanylate Cyclase Pathway Modulates the Rat Vas Deferens Contractility Induced by Phenylephrine
Authors: Pinto Rui , Mota‐Filipe Helder , Lima Beatriz Silva
Published: March 2003

Abstract: The involvement of the nitric oxide synthase/soluble guanylate cyclase pathway on the modulation of phenylephrine‐induced contractility in the rat vas deferens was investigated. Phenlylephrine‐concentration response curves were obtained in absence and in presence of inhibitors, NG‐Nitro‐L‐arginine (L‐NOARG), NG‐Nitro‐L‐arginine methyl esther (L‐NAME) or NG‐monomethyl‐L‐arginine (L‐NMMA) or GC inhibitior, 1H‐(1,2,4)‐oxadiaziol‐(4,3‐a)quinoxalin‐1‐one (ODQ) or nitric oxide donor, 3‐morpholinosydnonimine hydrochloride (SIN‐1) alone or together with L‐NMMA or ODQ. Both nitric oxide synthase and GC inhibitors reduced the Phe‐Emax. SIN‐1 alone did not change phenylephrine‐induced responses and it could reverse the L‐NMMA effect but not ODQ effect. The reduction of the phenylephrine‐induced contractility obtained in consequence of the inhibition of the nitric oxide/GC pathway suggest that, in the rat vas deferens, despite its well identified relaxant properties, nitric oxide potentiates the contractility induced by adrenergic stimulation.
Structure of Cholecystokinin Receptor Binding Sites and Mechanism of Activation/Inactivation by Agonists/Antagonists
Authors: Fourmy Daniel , Escrieut Chantal , Archer Elodie , Galès Céline , Gigoux Véronique , Maigret Bernard , Moroder Luis , Silvente‐Poirot Sandrine , Martinez Jean , Fehrentz Jean‐Alain , Pradayrol Lucien
Published: March 2003

Abstract: Delineation of CCK receptor binding sites is a prerequisite for the understanding of the molecular basis for ligand recognition, partial agonism, ligand‐induced traffiking of receptor signalling. In the current paper, we illustrate how, in the past 5 years, studies from our laboratory and others have provided new data on the molecular basis of the pharmacology and functioning of CCK1 and CCK2 receptors. Available data on CCK1 and CCK2R binding sites indicate that 1) homologous regions of the two receptors are involved in the binding site of CCK, however, positioning of CCK slightly differs; 2) binding sites of non‐peptide agonists/ antagonist are buried in the pocket formed by transmembrane helices and overlap that of CCK and 3) residues of the binding sites as well as of conserved motifs such as E/DRY, NPXXY are crucial for receptor activation.
Involvement of Cholecystokinin/Gastrin‐Related Peptides and their Receptors in Clinical Gastrointestinal Disorders
Authors: Jensen Robert T.
Published: March 2003

Abstract: In this paper the possible roles of cholecystokinin (CCK), gastrin, or gastrin‐related peptides and their receptors in human gastrointestinal diseases are reviewed. For CCK/CCKA receptors (CCKA‐R), the evidence for their proposed involvement in diseases caused by impaired CCK release or CCKA‐R mutations, pancreatic disorders (acute/chronic pancreatitis), gastrointestinal motility disorders (gallbladder disease, irritable bowel syndrome), pancreatic tumor growth and satiety disorders, is briefly reviewed. The evidence that has established the involvement of gastrin/CCKB‐R in mediating the action of hypergastrinaemic disorders, mediating hypergastrinaemic effects on the gastric mucosa (ECL hyperplasia, carcinoids, parietal cell mass), and acid‐peptic diseases, is reviewed. The evidence for their possible involvement in mediating growth of gastric and pancreatic tumours and possible involvement of gastrin‐related peptides in colon cancers, is reviewed briefly.
Effects of phototherapy on pressure ulcer healing in elderly patients after a falling trauma
Authors: Schubert Vivianne
Published: March 2003

Background: The effects of infrared and red pulsed monochromatic light, with varied pulsations and wavelengths, on the healing of pressure ulcers were evaluated in this prospective, randomized, controlled study.

Methods: Elderly patients (≥65 years) with Stage 2 or 3 skin ulcers were enrolled and assigned to one of two groups. Both groups were given the same standard ulcer therapy. One group was also given phototherapy with pulsed monochromatic infrared (956 nm) and red (637 nm) light. Treatments lasted 9 min each time using a regimen with pulse repetition frequency varied between 15.6 Hz and 8.58 kHz. Patients were followed for 10 weeks or until the ulcer was healed, whichever occurred first. The ulcer surface area was traced weekly.

Results: Patients treated with pulsed monochromatic light had a 49% higher ulcer healing rate, and a shorter time to 50% and to 90% ulcer closure compared with controls. Their mean ulcer area was reduced to 10% after 5 weeks compared with 9 weeks for the controls.

Conclusion: The results are encouraging as pulsed monochromatic light increased healing rate and shortened healing time. This will positively affect the quality of life in elderly patients with pressure ulcer.
Immunomodulatory effect of extracorporeal photopheresis after successful treatment of resistant renal allograft rejection
Authors: Baron Elma D. , Heeger Peter S. , Hricik Donald E. , Schulak James A. , Tary‐Lehmann Magdalena , Stevens Seth R.
Published: March 2003

Background: Acute renal allograft rejection contributes to patient morbidity. Standard immunosuppressives are only partially effective and have significant side effects. Extracorporeal photopheresis (ECP) has been effective in reversing the acute rejection process. T cell cytokine expression is implicated in rejection and tolerance but actual changes in the cytokine profile of ECP‐treated individuals have not been documented.

Methods: ECP was administered to a patient with acute renal allograft rejection resistant to other immunosuppressives. Enzyme‐linked immunosorbent spot (ELISPOT) assay was performed to determine the frequency of mitogen‐induced cytokine‐producing cells before and after ECP.

Results: ECP resulted in resolution of rejection; serum creatinine concentration fell from 7.1 to 2.2 mg/dl; ELISPOT revealed a three‐fold increase in the frequency of IL‐5 producing cells; IFN‐γ:IL‐5 ratio shifted from 2.73 pre‐treatment to 1.01 post‐treatment.

Conclusion: Effective therapy of acute allograft rejection with ECP alters the peripheral blood cytokine profile towards “type 2” cytokines, suggesting that alteration of T cell cytokine profiles may contribute to the resolution of the process.
PUVA and PUVB in vitiligo – are they equally effective?
Authors: El Mofty M. , Zaher H. , Esmat S. , Youssef R. , Shahin Z. , Bassioni D. , El Enani G.
Published: March 2003

Background/Aims: The combination of psoralens with different types of ultraviolet (UVL) sources in the treatment of vitiligo has led to different reports of success. The purpose of this trial is to compare in a random right‐left comparison study the efficacy and side effects of oral 8‐MOP plus UVA (PUVA) and oral 8‐MOP plus UVB (broadband, 290–320 nm P‐UVB) in the treatment of vitiligo.

Methods: The study included 24 cases of extensive vitiligo involving more than 30% of the body surface area in a bilateral symmetrical distribution. Each patient received 0.7 mg/kg 8‐MOP orally 2 h before the light session. The right side of the body was exposed to UVA (320–400 nm), while the left half was exposed to UVB (290–320 nm). The patients received 3 sessions/week for a total of 30 sessions.

Results: Both PUVA and PUVB produced moderate (50–60%) improvement, with similar incidences of phototoxic reaction and skin thickening. However, the study revealed a significant difference in the number of sessions needed to improve produce erythema and perifollicular pigmentation as well as a moderate response, the response on the UVA side always being earlier. Furthermore, the amount of joules needed to achieve the same response was 10 times greater on the UVA side than on the UVB side.

Conclusion: The use of psoralen plus broadband UVB is as effective as PUVA in the treatment of vitiligo. However, the long‐term side effects of psoralen plus UVB are unknown.
Pefloxacin and ciprofloxacin increase UVA‐induced edema and immune suppression
Authors: Sun Young Woo , Heo Eun Phil , Cho Yoon Hyang , Bark Ki‐Min , Yoon Tae Jin , Kim Tae Heung
Published: March 2003

Background: Quinolone antibiotics are popularly prescribed antibiotics because of their wide antibacterial spectrum and lowered bacterial resistance. Quinolone antibiotics are one of the well‐known photosensitizers that induce phototoxicity. Their role in photocarcinogenesis has been suggested in some studies.

Material and methods:

Mice were treated with two quinolone antibiotics (ciprofloxacin, which is less phototoxic, and pefloxacin, which is more phototoxic) to study the effect of the antibiotics on sunburn and immune suppression by ultraviolet A (UVA) irradiation. The effects of a combined treatment with UVA and these quinolone antibiotics were measured on back skin swellings, sunburn cell formations, depletion of epidermal Langerhans cells, and local and systemic suppression of contact hypersensitivity.

Results: Mice treated with both UVA and quinolone showed significantly increased back skin swellings and decreased epidermal Langerhans cells than mice treated with UVA only. Sunburn cells were increased significantly in mice treated with pefloxacin and 50 J/cm2 of UVA. Combination of pefloxacin and UVA suppressed local contact hypersensitivity significantly, but not systemic contact hypersensitivity.

Conclusion: Phototoxic quinolones augmented the effect of UVA by increasing sunburn and apoptosis, depleting Langerhans cells and suppressing local immune response. By affecting apoptosis and immune suppression, they may facilitate photocarcinogenesis caused by UVA.
Phototesting based on a divergent beam – a study on normal subjects
Authors: Ilias Michail A. , Wårdell Karin , Falk Magnus , Anderson Chris
Published: March 2003

In a previous publication from our group, phototesting based on a single exposure to a divergent UVB beam with radially decreasing irradiance values was suggested. The aim of the present study was to evaluate technical, practical and biological aspects of the suggested method in normal subjects. Twenty healthy volunteers were provoked on the back with both a collimated beam (four fixed doses, in circular areas with a diameter of 1.5 cm) and the divergent beam (a continuous, radially attenuating dose spectrum covering an area with a diameter of 4.5 cm). Eleven of the subjects were subjected to double provocation with the divergent beam. Assessment was carried out at 6 and 24 h after exposure by measuring the diameter of the reactions both visually and by mapping the skin blood flow change with laser Doppler perfusion imaging (LDPI). Minimal erythemal dose (MED) was determined for both the collimated and the divergent provocation. The reaction diameters were used to decide MED by combination to a mm for mm mapped dose spectrum of the divergent beam profile. Dose‐response curves were plotted using the quantitative response data of the LDPI‐images against the corresponding dosimetry data. No systematic difference could be proven between LDPI and visual diameters and a 95% confidence interval for the mean difference was calculated to (‐0.8, 2.0). Slightly greater diameters were found at the visual assessment performed at 6 h compared to 24 h (95% confidence interval (‐0.1, 2.8)). Double provocation showed a good reproducibility both for the visual and the LDPI assessment (P<0.05). The divergent beam provocation allowed a more detailed discrimination of MED compared to the collimated beam provocation. The MED values determined with the divergent beam were, however, generally higher, especially in the lower range of MED values. Technical factors related to the beam divergence and the correct measurement of erythemal effective irradiance are believed to be the explanation for this phenomenon, which is thus correctable. In conclusion, the results from this study support our belief that the phototesting protocol based on a divergent beam constitutes a good opportunity for improved phototesting, since MED and dose‐response characteristics may be extracted in more detail from a single UV exposure.
Long‐term treatment of erythropoietic protoporphyria with cysteine
Authors: Mathews‐Roth Micheline M. , Rosner Bernard
Published: March 2003

A Phase III 3 year placebo‐controlled trial, in which patients were blinded as to when placebo was given, was conducted to determine if the administration of L‐cysteine‐HCl was effective in preventing or ameliorating the photosensitivity associated with erythropoietic protoporphyria. Forty‐seven patients participated in the trial. Placebo was administered in the first month of the trial and then 500 mg of cysteine was given in two divided doses per day for the duration of the study. To measure efficacy, baseline and follow‐up visit history forms and light‐exposure diaries were filled in by the patients, and those seen in Boston were phototested. Analysis of the data from the questionnaires, the minutes of symptom‐free light exposure recorded in diaries and history forms and the results of the phototests showed that cysteine increased the time of symptom‐free light exposure to a statistically significant degree.
Melatonin protects fetal rat brain against oxidative mitochondrial damage
Authors: Wakatsuki Akihiko , Okatani Yuji , Shinohara Koichi , Ikenoue Nobuo , Kaneda Chitose , Fukaya Takao
Published: March 2003

Our objective was to investigate the effects of melatonin on the free radical‐induced oxidative damage to mitochondria in fetal rat brain. Female Wistar rats on day 19 of pregnancy were used. Melatonin (10 mg/kg) or vehicle (control) was injected intraperitoneally 60 min prior to laparotomy for removal of the fetuses. The mitochondrial fraction was isolated from the fetal rat brain of each group. Superoxide dismutase (SOD) and glutathione peroxidase (GSH‐Px) activities were measured. As indicators of mitochondrial respiratory activity, we determined the respiratory control index (RCI) and the adenosine 5‐diphosphate/oxygen (ADP/O) ratio in the presence and absence of 2.5 μM hypoxanthine and 0.02 units/mL xanthine oxidase. Mitochondrial lipid peroxidation was determined by measuring the concentration of thiobarbituric acid reactive substances in fetal brain mitochondria in the presence or absence of 2.5 μM hypoxanthine, 0.02 units/mL xanthine oxidase, and 50 μM FeSO4. The free radical‐induced rates of inhibition of mitochondrial RCI and the ADP/O ratio were both significantly lower in the fetal rat brains treated with melatonin compared with those of the controls (RCI, 44.25±15.02% vs. 25.18±5.86%, P<0.01; ADP/O ratio, 50.74±23.05% vs. 13.90±7.80%, P<0.001). The mitochondrial lipid peroxidation induced by free radicals was significantly reduced in the melatonin‐treated group compared with the controls (484.2±147.2% vs. 337.6±61.0%, P<0.01). Pretreatment with melatonin significantly increased the activity of GSH‐Px (20.35±5.27 to 28.93±11.01 mU/min mg−1 protein, P<0.05) in fetal rat brain mitochondria, but the activity of SOD did not change significantly. Results indicate that the administration of melatonin to the pregnant rat may prevent the free radical‐induced oxidative mitochondrial damage to fetal rat brain by a direct antioxidant effect and the activation of GSH‐Px.
Intracellular Ca2+ signaling pathway is involved in light‐induced phase advance, but may not be in phase delay, of the circadian melatonin rhythm in chick pineal cell
Authors: Nakahara Keiko , Murakami Noboru , Takigami Eri , Nasu Tetsuo , Murakami Takayuki , Shiota Kunio
Published: March 2003

Chick pineal cells have photoreceptive, circadian clock and melatonin synthetic capacities, and express circadian oscillation of melatonin release in vitro. Light pulses cause phase‐dependent phase shift of the melatonin rhythm. The purpose of this study was to address the questions whether intracellular calcium is involved in both light‐induced phase advance and delay. Thapsigargin and cyclopiazonic acid, which deplete the intracellular calcium stores, blocked the light‐induced phase advance in a dose‐dependent manner. The pulses of ryanodine receptor antagonist (dantrolene sodium or ruthenium red) also blocked the light‐induced phase advance. Most agents did not cause a significant phase shift by themselves. On the other hand, all the agents used, failed to block the light‐induced phase delay, even if the magnitude of phase delay was decreased using low intensity light. An antagonist of nitric oxide synthase blocked neither light‐induced phase advance nor phase delay. These results indicate the following possibilities: (1) the mechanism of light‐induced phase advance and delay may be different in chick pineal cells, or (2) if intracellular calcium is involved in both light‐induced phase advance and delay, the sensitivity to light and/or agents used in this study may differ according to Zeitgeber time.
Seasonal rhythms of 6‐sulphatoxymelatonin (aMT6s) excretion in female rats are abolished by growth of malignant tumors
Authors: Bartsch Hella , Bartsch Christian , Deerberg Friedrich , Mecke Dieter
Published: March 2003

The effect of development and growth of malignant tumors on pineal melatonin production was studied in two different hormone‐dependent tumor systems in female rats. Urinary excretion of 6‐sulphatoxymelatonin (aMT6s), the metabolic end product of melatonin, which parallels its production, was determined by radioimmunoassay at fortnightly or monthly intervals over the period of 1 year in female F344 Fischer rats bearing chemically‐induced mammary carcinomas and in BDII/Han rats with spontaneous endometrial carcinomas. Untreated Fischer rats and BDII/Han rats in which tumor growth was suppressed by treatment with a progestin served as controls. Based on the cosinor analysis, animals without tumors showed significant seasonal rhythms of aMT6s excretion, with peaks in August (Fischer rats) and in May (BDII/Han rats). In contrast, such rhythms were absent in animals with developing and manifest tumors. It is concluded that animals kept under constant environmental conditions still show seasonal rhythms of pineal activity. Tumor development and growth affect pineal activity leading to disturbance of these rhythms.
Effects of melatonin on fuel utilization in exercised rats: role of nitric oxide and growth hormone
Authors: Sánchez‐Campos S. , Arévalo M. , Mesonero M.J. , Esteller A. , González‐Gallego J. , Collado P.S.
Published: March 2003

We have previously reported that melatonin modifies carbohydrate and lipid utilization in exercised rats, maintaining glycemia and reducing plasma and liver lactate and plasma β‐hydroxybutyrate. This study was undertaken to determine whether effects on fuel metabolism were related to changes in nitric oxide (NO) production or growth hormone (GH) secretion. Male Wistar rats received melatonin i.p. at a dose of 0.5 mg/kg body weight 30 min before being exercised to exhaustion on a treadmill at a speed of 24 m/min and a 12% slope. Melatonin ameliorated the decrease in plasma glucose and the increase in plasma urea, free fatty acid, β‐hydroxybutyrate, and nitrite induced by exercise. Melatonin‐treated exercised rats had significantly elevated liver glycogen content and hepatic tissue showed a lowered expression of both inducible and constitutive NO synthase (iNOS and cNOS). Administration of the NO inhibitor NG‐nitro‐l‐arginine (l‐NAME) to exercised rats caused a significant reduction in plasma nitrite, but liver glycogen and biochemical parameters in blood did not significantly differ from untreated exercised animals, indicating the absence of a direct association between melatonin effects on fuel metabolism and NO levels. Although results of treatment with pyridostigmine, a cholinergic agonist drug that stimulates GH release, partially differed from that of melatonin, modulation of GH secretion could play a role in the metabolic actions of the hormone because effects of melatonin on exercised rats were almost completely blocked by simultaneous administration of l‐NAME.
Rejuvenation of degenerative thymus by oral melatonin administration and the antagonistic action of melatonin against hydroxyl radical‐induced apoptosis of cultured thymocytes in mice
Authors: Tian Yan‐Mei , Li Pi‐Peng , Jiang Xiao‐Fang , Zhang Gui‐You , Dai Yao‐Ren
Published: March 2003

The effect of melatonin on age‐related thymic involution and apoptosis induced by hydroxyl radicals (·OH) in mouse thymocyte cultures was investigated. Exogenous melatonin was administered in the drinking water (15 μg/mL) of 7‐month‐old male Balb/c mice for 40 consecutive days. Our results show that melatonin distinctly reversed the age‐related thymic involution as revealed by the notable increase of cellular density, particularly the number of thymocytes, percentage of thymocytes at G2+S phases and the younger morphological appearance as a whole when compared with control animals. More strikingly, the recovery of these morphometric parameters were maintained for 30 days after the termination of melatonin administration suggesting that the re‐established homeostasis by melatonin may last for a longer time. At the same time, when primary culture of thymocytes was preincubated with 200 μM melatonin before their exposure to hydroxyl radicals (·OH) generated by Fe2+‐mediated Fenton reaction, apoptotic cell death induced by ·OH was almost completely prevented as determined by both flow cytometric analysis and the TUNEL assay. DNA laddering assay also documented the inhibition of thymocyte apoptosis by melatonin. Furthermore, we found that the ·OH‐induced increment of caspase‐3 activity in thymocytes was completely abolished by melatonin preincubation. Taken together, our study indicates that in addition to other mechanisms, melatonin may also directly act as an antioxidant via attenuating apoptotic thymocyte death caused by free radicals and stimulates thymocyte proliferation in thymus and thus to rejuvenate the degenerative organ.
Circadian abnormalities in older adults
Authors: Youngstedt Shawn D. , Kripke Daniel F. , Elliott Jeffrey A. , Klauber Melville R.
Published: March 2003

This study examined the circadian phase adjustment of symptomatic elders ages 60–79 years in comparison with that of young, healthy adults ages 20–40 years. Seventy‐two elders with complaints of insomnia or depression, and 30 young, healthy adults were assessed for 5–7 days at home. Sleep and illumination were recorded with Actillume wrist monitors and sleep diaries. Urine was collected over two 24‐hr periods and assayed for 6‐sulphatoxymelatonin (6‐smt). The volunteers were then observed continuously for 5 nights and 4 days in the laboratory. In the laboratory, sleep periods were fixed at 8 hr with polysomnographic assessment of sleep, apnea‐hypopnea, and nocturnal myoclonus. Circadian dispersion, defined as the mean variation of 6‐smt acrophase from the median age‐specific acrophase, was significantly greater in the older vs. young adults. Likewise, circadian malsynchronization, defined as the absolute number of hours (advance or delay) between the 6‐smt acrophase and the middle of the sleep period, was significantly greater in the older vs. young volunteers. For the older volunteers, multiple regressions were calculated associating sleep with potential correlates of sleep disturbance. Nocturnal myoclonus and circadian malsynchronization were more strongly associated with sleep impairment than other factors (e.g., sleep apnea, depression). These observations suggest that circadian malsynchronization might be a common and significant cause of disturbed sleep among adults over age 60.
The effects of melatonin on Ca2+ homeostasis in endothelial cells
Authors: Pogan L. , Bissonnette P. , Parent L. , Sauvé R.
Published: March 2003

The effect of melatonin on the Ca2+ signaling process in bovine aortic endothelial cells (BAE) and in primary cultured vascular endothelial cells from normotensive Sprague Dawley (SDR) and genetically hypertensive (SHR) rats was investigated using the Ca2+ indicator Fura‐2. Acute applications of melatonin failed to initiate a Ca2+ response in the three cell types considered. However, preincubating SHR aortic endothelial cells with exposure to melatonin increased the internal Ca2+ release triggered by bradykinin (BK) and ATP while stimulating the related agonist‐evoked Ca2+ entry. This effect appeared specific for SHR cells, as a similar incubation period failed to alter the Ca2+ responses in BAE and SDR cells. Because of the known overproduction of free radicals in SHR cells, the effect of melatonin on Ca2+ signaling was also tested in SDR and BAE cells exposed to the superoxide anion radical. Melatonin reversed the deleterious action of free radicals on Ca2+ signaling in both cases, suggesting that its stimulatory effect in SHR was linked to its antioxidative properties. Finally, experiments where melatonin was applied between successive BK stimulation periods showed an enhancement of the agonist‐evoked Ca2+ entry in BAE and SDR cells. This effect appeared to be independent of the production of second messengers as no specific binding sites for melatonin, including MT1, MT2 and MT3 receptors, could be detected in BAE cells. We conclude that melatonin improves Ca2+ signaling in dysfunctional endothelial cells characterized by an overproduction of free radicals while stimulating the agonist‐evoked Ca2+ entry in normal endothelial cells through a mechanism not related to its antioxidative properties.
Daily rhythm of glucose‐induced insulin secretion by isolated islets from intact and pinealectomized rat
Authors: Picinato Maria C. , Haber Esther P. , Carpinelli Angelo R. , Cipolla‐Neto José
Published: March 2003

Abstract: It is well known that pinealectomy induces in rats a diminished glucose tolerance, insulin resistance, a reduction in GLUT4 content in adipose and muscular tissues, a decrease in hepatic and muscular glycogenesis, impairment of glucagon action and an increase in blood pyruvate concentration. In addition, it has been shown that melatonin suppresses insulin secretion in several experimental conditions. The objective of the present study was to investigate the daily rhythm of glucose‐induced insulin secretion and glucose oxidation by isolated pancreatic islets and to investigate the effect of chronic absence of melatonin (30 days of pinealectomy) on this rhythmic process. The data obtained confirmed the presence of a strong 24‐hr rhythm of insulin secretion by isolated pancreatic islets. In addition, it was demonstrated that the glucose‐metabolizing ability of the B‐cell follows a daily rhythm phase locked to insulin secretion rhythm. Most interesting, however, was the demonstration that the daily rhythmic processes of insulin secretion and B‐cell –[U‐14C]‐glucose oxidation by isolated pancreatic islets is completely modified by the chronic absence of the pineal gland. Thus, pinealectomy induced in all groups an increase in 24‐hr mean glucose‐stimulated insulin secretion and [U‐14C]‐glucose oxidation, in addition to some alterations in the rhythmic amplitude and a remarkable phase‐advancing of the daily curves for 8.3 mm glucose (a condition similar to that observed in fed animals and where the B‐cells are supposedly more active). These observations strongly suggest that the presence of the pineal gland may be necessary for the proper synchronization of these metabolic rhythms with other circadian rhythms like activity–rest and feeding.
Melatonin effects on bone: experimental facts and clinical perspectives
Authors: Cardinali Daniel P. , Ladizesky Marta G. , Boggio Verónica , Cutrera Rodolfo A. , Mautalen Carlos
Published: March 2003

Abstract: Bone formation proceeds through a remodeling process that runs continuously, involving the resorption of old bone by osteoclasts, and the subsequent formation of new bone by osteoblasts. This is controlled by growth factors and cytokines produced in bone marrow microenvironment and by the action of systemic hormones, like parathyroid hormone, estradiol or growth hormone (GH). One candidate for hormonal modulation of osteoblast and osteoclast formation is melatonin. Because circulating melatonin declines with age, its possible involvement in post‐menopausal and senescence osteoporosis is considered. This review article discusses early studies on melatonin–bone relationships and recent data that suggest a direct effect of melatonin on bone. Melatonin could act as an autacoid in bone cells as it is present in high quantities in bone marrow, where precursors of bone cells are located. Melatonin dose‐dependently augmented proteins that are incorporated into the bone matrix, like procollagen type I c‐peptide. Osteoprotegerin, an osteoblastic protein that inhibits the differentiation of osteoclasts is also augmented by melatonin in vitro. Another possible target cell for melatonin is the osteoclast, which degrades bone partly by generating free radicals. Melatonin through its free radical scavenger and antioxidant properties may impair osteoclast activity and bone resorption. At least in one study melatonin was both inhibitory to osteoclastic and osteoblastic cells. Therefore, the documented bone‐protecting effect of melatonin in ovariectomized rats can depend in part on the free radical scavenging properties of melatonin. Additionally, melatonin may impair development of osteopenia associated with senescence by improving non‐rapid eye movement sleep and restoring GH secretion. Whether melatonin can be used as a novel mode of therapy for augmenting bone mass in diseases deserves to be studied.
Purification and immunohistochemical analysis of calcium‐binding proteins expressed in the chick pineal gland
Authors: Shimizu Fumiko , Sanada Kamon , Fukada Yoshitaka
Published: March 2003

Abstract: The pineal gland is a site of melatonin production, of which intracellular calcium ions (Ca2+) are likely involved in various aspects. To investigate the identity of molecules responsible for the Ca2+‐dependent processes in the pineal cells, we prepared a cellular extract from 2000 chick pineal glands and isolated a series of Ca2+‐binding proteins by taking advantage of their Ca2+‐dependent hydrophobic interaction with phenyl‐Sepharose beads. The proteins identified by micro‐sequencing analysis included calmodulin, neurocalcin, sorcin, annexin II and annexin V. Immunohistochemical analysis of the chick pineal sections revealed that both calmodulin and sorcin are expressed in the follicular and parafollicular pinealocytes. On the other hand, neurocalcin was expressed in a few neuron‐like cells located predominantly in the parafollicular layer of the pineal follicle. These results suggest that calmodulin and sorcin may contribute to cellular functions in the chick pinealocytes.
Relationship between perceived readiness to run and physiological variables during repeated 2000 m bouts in middle‐distance runners
Authors: Karu T. , Nurmekivi A. , Lemberg H. , Pihl E. , Jürimäe T.
Published: March 2003

The aim of this study was to investigate how heart rate (HR) and blood lactate (LA) concentrations are associated with perceived readiness ratings (PRR) to begin a new run during recovery after four different intensity steady‐state 2000 m runs in college‐level male middle‐distance runners (n=15). A typical 4×2000 m run test with stepwise increasing speed was used on the indoor track (150 m lap). A new PRR scale was administred at each minute of recovery. The scale ranges from 1 to 5 points (from “not at all ready to begin” to “completely ready to begin”). Blood LA concentrations were measured immediately after runs and in the 3rd min of recovery after the first and second runs. In case of the third and fourth runs, blood LA was measured immediately after the runs and in the 3rd and 6th min of recovery. HR was recorded at the end of every minute of recovery. Highly significant inverse relationships were revealed between PRR, blood LA concentrations and HR during recovery (r>0.9 as a rule). After the third and the fourth 2000 m runs, where intensity was higher than LA threshold, PRR increased during 6 min up to 4.8±0.4 and 4.5±0.6, respectively, while HR fell below 120 beats  ·  min−1. However, blood LA concentration remained high. The reliability of the new PRR scale (tested on four runners), during recovery was very high (r=0.98). These results suggest that the PRR scale can be used by runners to determine the optimal duration of resting intervals between runs.
Associations of leisure‐time physical activity and obesity with atherogenic lipoprotein‐lipid markers among non‐smoking middle‐aged men
Authors: Carroll S. , Cooke C. B. , Butterly R. J. , Gately P.
Published: March 2003

The association of both leisure‐time physical activity and obesity with lipoprotein‐lipids and composite atherogenic markers were examined within a cross‐sectional study of middle‐aged men of higher socioeconomic status. Analyses were performed on a subsample (n=629) of non‐smoking, non‐diabetic men (46.7±7.8 years) who completed a preventive medical assessment between 1992 and 1996. Mean adjusted (age, body mass index (BMI), sum of skinfolds, fasting glucose, and logarithmic alcohol consumption) levels of high‐density lipoprotein‐cholesterol (HDL‐C) were significantly higher, and logarithmic triglycerides significantly lower, with higher physical activity index (PAI) categories (both P<0.0001). Significantly lower adjusted mean ratios of both total cholesterol to HDL‐C (TC:HDL‐C), and logarithmic triglycerides to HDL‐C (TG:HDL‐C) with higher PAI were evident following adjustment for the above covariates (P=0.005 and P<0.0001). Age‐adjusted non‐HDL‐C (total cholesterol minus HDL‐C) decreased significantly with higher PAI categories, but was not significantly lower following covariate adjustment (P=0.150). On stepwise multiple regression, logarithmic physical activity score and BMI explained 9.5–14% of the variance in the TC:HDL‐C and TG:HDL‐C ratios in models including age, body mass, sum of skinfolds, fasting glucose and logarithmic alcohol consumption. Age, sum of skinfolds and logarithmic alcohol consumption were significant predictors of non‐HDL‐C (r2=8.0%). These findings emphasise the importance of both physical activity and obesity in predicting lipoprotein‐lipid risk markers.
Is exercise of value in the prevention of fragility fractures in men?
Authors: Karlsson M.
Published: March 2003

Exercise during growth seems to build a stronger skeleton resulting in a high peak bone mineral density (BMD) in men. Exercise during adulthood produces benefits in BMD or prevents bone loss, but the changes are of minor biological significance as regards fracture reduction. However, prospective intervention studies suggest exercise to improve muscle strength, co‐ordination and balance, even in octogenarians—all traits possible to reduce the number of falls. It is virtually impossible to undertake a randomized blinded study of exercise with fracture as end point due to the large cohorts needed. Retrospective and prospective observational and case control studies suggest activity to be associated with reduced fracture risk. This may be correct, but consistently replicated sampling bias may produce the same observation. The Achilles heel of exercise is the cessation of physical activity. Biologically important benefits in BMD or improvement in muscle size and strength achieved by exercise during growth and young adulthood seem to be eroded in retirement, leaving virtually no remaining benefits in old age, the period when fragility fractures exponentially rise. On the contrary, continued exercise on a lower level may maintain some of the musculoskeletal benefit, but dose– response relationships need to quantified, as do the effects of exercise on bone size, shape, architecture and frequency of injurious falls. Absence of evidence is not evidence of absence of effect, but if we recommend exercise then should this be to children, adults, elderly men or men with fractures? What type of exercise? For how long? How many fewer fractures will result in the community from a community based exercise campaign like the anti‐tobacco campaign? The higher level of proof, suggesting exercise to reduce spine and hip fractures must come from well designed and executed prospective randomized studies. Blinded studies obviously cannot be done but open trials can, and should be undertaken.
Lesion classification using skin patterning
Authors: Round Andrew J. , Duller Andrew W. G. , Fish Peter J.
Published: March 2003

Background/aims: The observation that skin line patterning tends to be disrupted by malignant but not non‐malignant skin lesions suggests that this could be used as an aid to lesion differentiation. Since recognised differentiating features can be obtained from the simply‐captured white light optical image, the possibility of using such images for skin pattern disruption detection is worth exploring.

Methods: The skin pattern has been extracted from optical images by high‐pass filtering and profiles of local line strength variation with the angle estimated using a new consistent high‐value profiling technique. The resultant profile images have been analysed using a novel region‐based agglomerative clustering technique (mRAC) and also a local variance measurement. A measure based on the relationship between the classification results and an intensity‐based segmentation was calculated, and this represented the disruption of the skin line patterning.

Results: A set of images containing a variety of histologically confirmed malignant and non‐malignant lesions was analysed. The computed textural disruption figure was compared to both the histological diagnosis and to a visual estimate of patterning disruption for each image. It was demonstrated that lesion separation could be achieved by both analysis methods, with a good correlation with visual estimate of disruption and with mRAC providing the best performance.

Conclusions: It was concluded that the acquisition and modelling of skin line patterning from clinical images of skin lesions had been successfully achieved and that the analysis of the resulting data provided an assessment of pattern disruption that is both consistent with visual inspection and effective in presenting information useful for discrimination between melanoma and benign naevi lesion examples.
Viscoelastic properties of human skin and processed dermis
Authors: Silver Frederick H. , Freeman Joseph W. , DeVore Dale
Published: March 2003

Background/aims: The purpose of this work is to attempt to determine the elastic spring constant for collagen and elastic fibers (elastin) in skin and to detemine if the values of these elastic constants are similar to those reported for other tissues.

Methods: We studied the viscoelastic mechanical properties of human skin and dermis by measuring the incremental stress‐strain behavior. Elastic stress‐strain curves were used to obtain the elastic spring constant of elastin and collagen while the collagen fibril length was obtained from the slope of viscous stress‐strain curves.

Results: Our results suggest that the elastic spring constant for elastin is about 4.0 MPa while that for collagen is about 4.4 GPa. The former value is similar to that calculated for ligamentum nuchae while the latter value is about 70% of the value found for tendon and self‐assembled type I collagen fibers. The differences between the elastic constants for collagen molecules in tendon and skin is hypothesized to reflect the higher molecular tilt angle and lower D period found in skin compared to tendon as well as a shorter fibril length.

Conclusion: The differences in the collagen types present in skin and tendon may influence collagen self‐assembly and the resulting viscoelastic properties.
Efficacy testing of cosmetic products*
Authors: Serup Jørgen
Published: March 2003

Background/aims: Regulations for cosmetic products primarily address safety of the products that may be used by large populations of healthy consumers. Requirements for documentation of efficacy claims are only fragmentary. This synopsis aims to review and conclude a set of standards that may be acceptable to the European Community, and the cosmetic industry, as a legal standard for efficacy documentation in Europe in the future.

Methods and Results: Ethical, formal, experimental, statistical and other aspects of efficacy testing are described, including validation, quality control and assurance. The importance of user relevant clinical end points, a controlled randomized trial design and evidence‐based cosmetic product documentation, validation of methods, statistical power estimation and proper data handling, reporting and archiving is emphasized. The main principles of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) good clinical practice (GCP) should be followed by the cosmetics industry in a spirit of good documentation standard and scientific soundness, but full GCP is not considered mandatory in the field of cosmetics. Documentation by validated bio‐instrumental methods may be acceptable, but efficacy documentation based on information about raw materials, reference to literature and laboratory experiments are only acceptable in exceptional cases.

Conclusions: Principles for efficacy substantiation of cosmetic products in Europe, as described in this synopsis, are officially proposed by the Danish Ministry of Environment and Energy to the European Community as a basis for an amendment to the Cosmetics Directive or otherwise implemented as a European Community regulation.
The NO release test as a functional reference standard for laser Doppler fluxmetry in cutaneous microangiology
Authors: Wohlrab Johannes , Körting Ramona , Helmbold Peter , Marsch Wolfgang Ch.
Published: March 2003

Background/aims: The application of one‐dimensional laser Doppler fluxmetry (LDF) to clinical research is widespread. Large intra‐ and interindividual fluctuations in perfusion impede the objective evaluation of studies and hinder a standardised reproducibility. Attempts are made to minimise these biological fluctuations of the measured values by means of functional tests, standardised measuring conditions and large study populations. An intraindividual fixed standard that also facilitates interindividual comparability as a reference parameter would be desirable.

Methods: By applying a nitric oxide (NO) release cream, a maximal vasodilatation is produced in a circumscribed skin area and optically registered by means of LDF. An LDF quotient is defined as a measure of the reproducibility. A total of 123 test subjects with dermatological diseases were measured at intervals of 60 min on the volar underarm on clinically normal skin with and without NO release cream.

Results: The LDF quotient of the NO release test represents a stable, readily reproducible individual parameter and is appropriate as a reference standard for resting flux measurements. Therefore, we define an LDF factor that includes the maximal vasodilatation as a specific assessment characteristic and thus allows a more powerful, functionally oriented assessment of the individual measurements.

Conclusion: The NO release test is appropriate as a reference standard for laser Doppler fluxmetry and realises a high reproducibility of individual measurements.
Evaluation of facial skin type by sebum secretion: Discrepancies between subjective descriptions and sebum secretion
Authors: Youn Sang Woong , Kim Soo Jung , Hwang In A , Park Kyoung Chan
Published: March 2003

Background/aims: Facial skin is usually classified as dry, normal, and oily in the cosmetics field. However, there is no standard objective method for classifying facial skin.

Methods: We measured sebum excretion with Sebumeter® at four sites on the face. Based on the amount of sebum secretion, we reclassified skin type according to the guidelines provided by the manufacturer. The mean of sebum excretion (mean facial sebum excretion; MFSE) was also calculated.

Results: People secrete varying amounts of sebum at different skin sites. Reclassification of skin type based on sebum secretion revealed that most participants underestimated the amount of facial sebum excretion. When sebum secretion amounts were compared, a statistically significant difference was apparent between the oily and dry skin types. However, there were no statistical differences between oily and normal, and normal and dry skin.

Conclusion: We showed that subjective skin type does not match the amount of sebum secreted. Thus, this simple and subjective classification is of very limited use and it should be re‐evaluated by using an objective and standardized measuring tool.
Actin Assembly at Membranes Controlled by ARF6
Authors: Schafer Dorothy A. , D'souza‐Schorey Crislyn , Cooper John A.
Published: March 2003

The small GTPase, ADP‐ribosylation factor‐6 (ARF6), has been implicated in regulating membrane traffic and remodeling cortical F‐actin. Using real‐time video analysis of actin assembly in living cells, we investigated the function and mechanism of ARF6 in control of actin assembly. Expression of an activated form of ARF6 that mimicks the GTP‐bound form of the GTPase induced actin assembly resulting in the movement of vesicle‐like particles, some of which contain markers for pinosomes. Activated ARF6 also stimulated actin assembly at foci on the ventral surface of the cell and stimulated fluid phase pinocytosis. Particle motility induced by ARF6 involved Arp2/3 complex, tyrosine kinase activity, phospholipase D (PLD) and D3‐phosphoinositides, but not phosphatidylinositol 4,5‐bisphosphate (PI(4,5)P2). We conclude that ARF6 regulates actin assembly for pinosome motility and at foci on the ventral cell surface.