bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of the intracellular and extracellular serotonin in the regulation of melatonin production in rat pinealocytes
Authors: Miguez Jesús M. , Simonneaux Valérie , Pevet Paul
Published: February 2007

Miguez JM, Simonneaux V, Pevet P. The role of the intracellular and extracellular serotonin in the regulation of melatonin production in rat pinealocytes. J. Pineal Res. 1997; 23:63–71. © Munksgaard, Copenhagen

This study investigated whether the activation of pinealocyte β‐adrenergic receptors is involved in the regulation of serotonin (5‐HT) synthesis and release, as it is for melatonin production. In addition, the role of the intra‐ and extra‐cellular 5‐HT in modulating the synthesis of melatonin induced by the β‐adrenergic agonist isoproterenol (ISO) was also studied. The incubation of dissociated pinealocytes with 0.1–10 IAM ISO resulted in a concentration‐dependent increase of melatonin synthesis. 5‐HT release and intracellular 5‐HT content were increased by 0.1 and 1 μM ISO but they were reduced after ISO 10 μM. Moreover, when incubated with the tryptophan hydroxylase inhibitor p‐chlorophenylalanine (PCPA), the secretion of 5‐HT as well as the intracellular 5‐HT levels were markedly reduced in both ISO‐stimulated and unstimulated conditions. Melatonin release was also inhibited by PCPA, although it responded in the expected manner to increasing concentrations of ISO. These data indicate that the release of 5‐HT from pinealocytes depends on the availability of cytoplasmic 5‐HT, which in turn is highly dependent on the tryptophan hydroxylase activity. In cells stimulated with moderate ISO concentrations, 5‐HT release may be an important regulatory process of pineal 5‐HT. After a large stimulation of N‐acetyltransferase (NAT) activity by ISO, the synthesis of melatonin prevails on 5‐HT release, whose decrease is associated to a deficit of intracellular 5‐HT. On the other hand, the present study shows that the incubation of pineal cells with high concentrations of 5‐HT or with a selective 5‐HT2 receptor agonist, α‐methyl‐5‐hydroxytryptamine, reverses partially the inhibitory effect of PCPA on the ISO‐stimulated melatonin synthesis. In contrast the 5‐HT2 antagonist, ketanserin, results in an inhibiton of the release of melatonin following ISO stimulation. These results suggest that released 5‐HT may have a role in the full expression of the β‐adrenergically induced NAT activity and, thus, may contribute to the optimal melatonin synthesis at night.
Intracellular melatonin distribution in cultured cell lines
Authors: Finocchiaro Liliana M. E. , Glikin Gerardo C.
Published: February 2007

Finocchiaro LME, Glikin GC. Intracellular melatonin distribution in cultured cell lines. J. Pineal Res. 1998; 24:22–34. © Munksgaard, Copenhagen

A specific antibody combined with a fluorescein‐labeled immunoglobulin was used to investigate the topographic distribution of melatonin in a variety of cells of different origins. Positive identification of both nuclear and cytosolic melatonin was confirmed in all the tested cells: Swiss 3T3 mouse fibroblasts, BCG1 bovine granulosa, NB41A3 mouse neuroblastoma, F9 mouse teratocarcinoma, MDCK normal canine kidney derived and human HeLa cell lines, as well as in human peripheral blood mononuclear leukocytes and rat splenic cells. In 3T3 mouse fibroblasts melatonin immunofluorescence partially colocalized with actin and serotonin immunostaining, but not with tubulin or actin stress fibers. Several distinct patterns of subcellular melatonin distribution, different from the bromodeoxyuridine‐labeled replication profiles, have been discerned throughout the cell cycle of synchronized 3T3 cells. In addition, synchronized 3T3 mouse fibroblasts cultured in the presence of 10‐‐3 M melatonin progressed more slowly through the cell cycle than control cells. These results suggest that melatonin may interact directly with nuclear and cytoskeletal structures probably affecting different cell functions such as cell cycle control, subcellular organization, and genome stability.
Melatonin supplementation does not prevent photostimulatory effects of night interruption lighting in Japanese quail
Authors: Meyer Wayne
Published: February 2007

Meyer W. Melatonin supplementation does not prevent photostimulatory effects of night interruption lighting in Japanese quail. J. Pineal Res. 1998; 24:102–107. © Munksgaard, Copenhagen

Male Japanese quail (Coturnix japonica) exposed to night interruption lighting were given melatonin either as single daily injections (10–100 mg/kg), or as continuous release implants. Birds were exposed to a base photoperiod of 8 hr of light, plus a 15 min night interruption pulse of light 14 hr after the beginning of the base photoperiod. Daily injections of melatonin were given 20 min prior to the night interruption pulse. Control birds either received no exogenous melatonin or received injections during the last 2 min of the night interruption pulse. Exogenous melatonin was able to induce sleep‐like behavior at higher doses but did not prevent gonadal recrudescence as measured by the cloacal protrusion area. The role of melatonin in avian reproduction appears to be different from that in mammals. Perhaps melatonin's role in birds is to regulate circadian activities, not circannual ones such as the onset of reproduction.
Molecular and cellular analyses of melatonin receptor‐mediated cAMP signaling in rat corpus epididymis
Authors: Li Li , Xu Jian N. , Wong Yung H. , Wong Joseph T.Y. , Pang Shiu F. , Shiu Stephen Y. W.
Published: February 2007

Li L, Xu JN, Wong YH, Wong JTY, Pang SF, Shiu SYW. Molecular and cellular analyses of melatonin receptor‐mediated cAMP signaling in rat corpus epididymis. J. Pineal Res. 1998; 25:219–228. © Munksgaard, Copenhagen

By using 2‐[125I]iodomelatonin receptor binding studies, we have previously demonstrated high affinity melatonin receptors, the binding activities of which are regulated by testosterone, in the corpus epididymis of rats. In this report, some of the basic molecular and cellular characteristics of these high affinity melatonin receptors in rat corpus epididymis were analyzed. MEL1A and MEL1B receptor mRNAs were expressed by rat corpus epididymal epithelial cells as revealed by in situ hybridization. Functionally, these high affinity melatonin receptors are negatively coupled to adenylyl cyclase via pertussis toxin (PTX) sensitive Gi protein and the inhibitory effects of melatonin on forskolin‐stimulated cAMP accumulation were enhanced by 5α‐dihydrotestosterone (5α‐DHT). Interestingly, opposing interactions between melatonin and (β‐adrenergic receptor signaling in rat epididymal epithelial cells were observed with melatonin inhibiting norepinephrine‐ and isoproterenol‐stimulated cAMP accumulation. In conclusion, our data support a modulatory action of melatonin, mediated via pertussis toxin‐sensitive Gicoupled MEL1A and MEL1B receptors, in androgenic and adrenergic regulation of rat corpus epididymal epithelial cell functions.
Chronic exposure to 2.9 mT, 40 Hz magnetic field reduces melatonin concentrations in humans
Authors: Karasek Michal , Woldanska‐Okonska Marta , Czernicki Jan , Zylinska Krystyna , Swietoslawski Jacek
Published: February 2007

Karasek M, Woldanska‐Okonska M, Czernicki J, Zylinska K, Swietoslawski J. Chronic exposure to 2.9 mT, 40 Hz magnetic field reduces melatonin concentrations in humans. J. Pineal Res. 1998; 25:240–244. © Munksgaard, Copenhagen

Diurnal rhythm of serum melatonin concentrations was estimated in 12 men with low back pain syndrome before and after exposure to a very low‐frequency magnetic field (2.9 mT, 40 Hz, square wave, bipolar). Patients were exposed to the magnetic field for 3 weeks (20 min per day, 5 days per week) either in the morning (at 10: 00 hr) or in the late afternoon (at 18: 00 hr). Significant depression in nocturnal melatonin rise was observed regardless of the time of exposure. This phenomenon was characteristic for all the subjects, although the percent of inhibition of melatonin secretion varied among the studied individuals.
Existence and function of opioid receptors on nammalian pinealocytes
Authors: Govitrapong Piyarat , Jitaijamjang W. , Chetsawang B. , Phansuwan‐Pujito Pansiri , Ebadi Manuchair
Published: February 2007

Abstract: Previous studies in our laboratories have identified a single population of opioid receptors in bovine pineal gland, which we have chosen to characterize further on pinealocytes isolated from the cow and rat pineal gland. The bovine pinealocytes isolated by trypsinization or mechanical manipulation revealed receptor density (Bmax) values of 206.95 ± 131.15 and 220.34 ± 11.80 fmol/mg protein, respectively, and dissociation equilibrium constant (Kd) values of 1.93 ± 0.48 and 1.96 ± 0.21 nM, respectively. The rat pinealocytes cultured for 7 days exhibited a [3H]diprenorphine binding site of 56 fmol/106 cells. Morphine (100 μM) enhanced the activity of N‐acetyltransferase and the level of melatonin in rat pineal gland in culture incubated for 21 hr. The results of these studies suggest that opioidergic receptors exist on pinealocytes and they are involved in stimulating the activity of N‐acetyltransferase and the synthesis of melatonin, thereby regulating the physiology of mammalian pineal gland.
Estrogen modulates the nocturnal synthesis of melatonin in peripubertal female rats
Authors: Okatani Yuji , Hayashi Kazutoshi , Watanabe Kazushi , Morioka Nobuyuki , Sagara Yusuke
Published: February 2007

Abstract: Our objective was to evaluate the effects of estrogen deficit and of estrogen stimulation on the synthesis of pineal melatonin in female rats during the peripubertal period. The levels of melatonin and N‐acetylserotonin (NAS) and the activities of N‐acetyltransferase (NAT) and hydroxyindole‐O‐methyltransferase (HIOMT) were determined in homogenates of pineal glands obtained from peripubertal female Sprague‐ Dawley rats 4 to 12 weeks of age in the mid‐dark during the daily light/dark cycle. Animals were ovariectomized at 4 weeks of age; daily administration of estradiol benzoate (E2B, 1.0 μg/d, s.c.) was initiated at 4 weeks of age. A peak in the pineal levels of melatonin and NAS and in NAT activity was observed in untreated (control) rats with intact ovaries at 6 weeks. HIOMT activity increased from Week 4 to 6 and remained unchanged thereafter. Ovariectomy at Week 4 led to significant increases in the levels of melatonin and of NAS and NAT in activity at Week 8. NAT activity Week 10 resembled that of control animals, but levels of melatonin and NAS were slightly elevated. Ovariectomy did not affect HIOMT activity. Subcutaneous injection of E2B significantly decreased the levels of melatonin and NAS and of NAT activity at Week 4, as compared with those in control rats. E2B suppressed the ovariectomy‐induced elevation of levels of melatonin and NAS and of NAT activity, similar to the effect in control animals. E2B did not affect HIOMT activity. Our results suggest that estrogen modulates the nocturnal synthesis of melatonin in the pineal gland in peripubertal female rats. The effects of estrogen on melatonin synthesis appeared to be mediated by the modulation of NAT activity.
Twenty‐four hour rhythm of melatonin in patients with a history of pineal and/or hypothalamo‐neurohypophyseal germinoma
Authors: Murata Jun‐ichi , Sawamura Yutaka , Ikeda Jun , Hashimoto Satoko , Honma Ken‐ichi
Published: February 2007

Abstract: Melatonin deficiency after a pinealectomy has been investigated in animals; however, in humans, this status can be assessed solely by investigating patients with a tumor originating in the pineal gland. This study analyzes secretion of melatonin and pituitary hormones in 14 patients with germinoma originating in the pineal or the hypothalamic‐neurohypophyseal region. Thirteen patients had been successfully treated prior to this study. One patient was included in this study before the initiation of treatments. Plasma sampling was performed every 2 hr for 24 hr and melatonin concentrations were measured by radioimmunoassay. Melatonin secretion was nearly absent in the patients with pineal germinoma regardless of treatment option, even in the patient who had been untreated. In contrast, melatonin secretion and its circadian rhythms were not affected in patients with a hypothalamo‐neurohypophyseal germinoma. The circadian rhythms of growth hormone and adrenocorticotropic hormone were not dysregulated in patients with the melatonin deficiency. We conclude that germinoma cells originating the pineal gland impair the production of melatonin by pineocytes and consequently induce a permanent melatonin deficiency in those patients. Since melatonin exerts multiple physiological functions, once a clinical concept of “melatonin deficiency syndrome” is established, melatonin replacement therapy could be investigated in patients who have a pineal germinoma or who have undergone a neurosurgical pinealectomy.
Melatonin concentrations in the luminal fluid, mucosa, and muscularis of the bovine and porcine gastrointestinal tract
Authors: Bubenik George A. , Hacker Roger R. , Brown Gregory M. , Bartos Ludek
Published: February 2007

Abstract: Melatonin concentrations were measured in serum, luminal fluid, and tissues of the mucosa and muscularis of the entire bovine and porcine gastrointestinal tract (GIT). In both species, GIT levels profoundly exceeded serum levels. In pigs, melatonin was lowest in the luminal fluid and highest in the mucosa. No difference was found in various layers of bovine GIT. Compared to pigs, cows had higher melatonin levels in the stomach and ileum, but lower in the cecum and colon. There was no difference in melatonin levels between anterior and posterior segments of bovine GIT, whereas pigs exhibited several fold higher concentration of melatonin in the posterior segment (cecum and colon). Conversely, melatonin values in the anterior segment were significantly higher in cows, but in the posterior segments porcine values were higher. In cows, concentrations in the mucosa correlated with levels in the muscularis. Melatonin levels in the mucosa and muscularis were higher in the rumen and reticulum than in the omasum and abomasum. The species‐specific levels and a distinct distribution of melatonin in the layers of the digestive tube indicates that this indole may be involved in the modulation of gastrointestinal function of monogastric as well as polygastric ungulates, albeit in a different capacity.
Protective effect of melatonin on indomethacin‐induced gastric injury in rats
Authors: De La Lastra Catalina Alarcón , Motllva Virginia , Martin Maria José , Nieto Ana , Barranco María Dolores , Cabeza Juan , Herrerías Juan Manuel
Published: February 2007

Abstract: The gastric injury associated with nonsteroidal anti‐inflammatory drug (NSAID) therapy has been linked to the detrimental effects of the agents on the processes of prostaglandin synthesis, neutrophil (PMN) activation, and oxygen free radical generation. In the present study, we investigated the in vivo protective effects of melatonin on indomethacin‐induced gastric lesions in the rat. Peroxidation of lipids and changes in the activities of related enzymes such as glutathione peroxidase (GSH‐px) and myeloperoxidase (MPO), as a marker of PMNs infiltration, were also studied. Intraperitoneal (i. p.) injection of melatonin (0.25, 0.5, 1 mg kg−1) 30 min before indomethacin administration prevented gastric injury. The mean ulcer indices significantly (P < 0.05) decreased. Thiobarbituric acid (TBA) reactive substances in the gastric mucosa as an index of peroxidation, was increased after indomethacin administration and this increase was inhibited by melatonin. In addition, pretreatment with melatonin resulted in a significant increase of the enzymatic GSH‐px activity up to the control levels; however, inhibition of ulceration by melatonin was not associated with a significant reduction in PMN infiltration. These results suggest that the protection afforded by the pineal hormone against indomethacin‐induced gastric injury may be, in addition to other possible mechanisms, to its radical scavenging activity.
Melatonin receptor potentiation of cyclic AMP and the cystic fibrosis transmembrane conductance regulator ion channel
Authors: Nelson Cole S. , Marino Jennifer L. , Allen Charles N.
Published: February 2007

Abstract: We have used the cystic fibrosis transmembrane conductance regulator (CFTR) CI‐ channel as a model system to study the cAMP signal transduction pathways coupled to the Xenopus melatonin receptor. During forskolin (Fsk) stimulation, melatonin reduced the amplitude of the CFTR currents in oocytes injected with in vitro transcribed cRNAs for the Xenopus melatonin receptor and CFTR. Pertussis toxin (Ptx) treatment eliminated melatonin inhibition of Fsk stimulated CFTR currents. In oocytes injected with cRNA for melatonin receptors, serotonin receptors (5‐HT7). and CFTR CI− channels, application of melatonin together with serotonin (5‐HT) activated an additional inward current showing potentiation of adenylyl cyclases by melatonin receptors. Subthreshold activation of 5‐HT7 receptors was sufficient and necessary to permit activation of CFTR channels by melatonin. Preexposure to melatonin desensitized the melatonin receptor mediated response. Therefore, based on this model system, the effects of melatonin in vivo could be either positive or negative modulation of other neuronal inputs, depending on the mode of adenylyl cyclase stimulation.
In the field mouse Mus booduga melatonin phase response curves (PRCs) have a different time course and wave form relative to light PRC
Authors: Sharma Vijay Kumar , Chandrashekaran Maroli K. , Singaravel Muniyandi , Subbaraj Ramanujam
Published: February 2007

Abstract: The phase shifting effects of the pineal hormone melatonin on the circadian locomotor activity rhythm of the field mouse Mus booduga was examined at various phases of the circadian cycle using single melatonin injections of two concentrations (10 mg/kg, high dose; and 1 mg/kg, low dose) and two phase response curves (PRCs) were constructed. A single dose of melatonin administered during the early subjective day evoked maximum phase delays, and during the late subjective night evoked phase advances in the locomotor activity rhythm. Other phases of the circadian cycle also responded to melatonin. The interval between circadian time 19 (CT19) and CT2 of the high dose melatonin PRC is marked by significant phase advances, whereas the interval between CT2 and 19 is marked by significant phase delays. A single dose of melatonin of strength 10 mg/kg was found to evoke phase shifts that were of comparable magnitude to those of the phase shifts evoked by natural daylight pulses. Control animals, treated with 50% dimethyl sulfoxide (DMSO), did not respond with phase shifts significantly greater than zero. Significant differences between the shapes of the two melatonin PRCs exist. Further melatonin PRCs appear to have a different time course and wave form relative to light‐induced PRC.
Mechanisms underlying the effects of estrogen on nocturnal melatonin synthesis in peripubertal female rats: Relation to norepinephrine and adenylate cyclase
Authors: Hayashi Kazutoshi , Okatani Yuji
Published: February 2007

Abstract: We previously reported that estrogen modulates the nocturnal synthesis of melatonin in the pineal gland of peripubertal female rats. These effects appeared to be mediated by the modulation of N‐acetyltransferase (NAT) activity. The present study assessed the mechanism underlying the effects of estrogen deficiency and stimulation on pineal melatonin synthesis in peripubertal female rats. We measured the norepinephrine levels and adenylate cyclase activity in pineal gland homogenates obtained from 4–10‐wk‐of‐age female Sprague Dawley rats at mid‐dark during the daily light/dark cycle. The animals were ovariectomized and daily s. c. administration of estradiol benzoate (E, B, 1.0 μg/d) was initiated at 4 wk of age. Pineal norepinephrine levels increased significantly from Week 3 to 4 (P <0.0001), and remained unchanged thereafter. Neither ovariectomy nor E2B administration significantly affected norepinephrine levels, Adenylate cyclase activity in the pineal gland peaked at 4 wk in untreated (control) rats. Ovariectomy at Week 4 led to a significant increase in adenylate cyclase activity at Week 8. At Week 10, adenylate cyclase activity returned to control levels. S. c. injection of E2B suppressed the ovariectomy‐induced increase in adenylate cyclase activity to the level seen in control rats. These changes in mid‐dark adenylate cyclase activity resembled those previously observed with NAT activity. The results suggest that estrogen modulates adenylate cyclase activity in the pineal gland of peripubertal female rats. The inhibitory effect of estrogen on melatonin synthesis appeared to be mediated, in part, by changes in the norepinephrine‐induced stimulation of pineal adenylate cyclase activity.
Melatonin inhibits the vasorelaxant action of peroxynitrite in human umbilical artery
Authors: Okatani Yuji , Wakatsuki Akihiko , Morioka Nobuyuki , Watanabe Kazushi
Published: February 2007

Abstract: We evaluated the antioxidant property of melatonin as it relates to the vasorelaxant effect of peroxynitrite (ONOO−), a reaction product of superoxide anion radical (O−2*) and nitric oxide (NO), on the human umbilical artery. Helical sections of umbilical arteries were obtained from human placentas at elective cesarean delivery between weeks 37 and 39 of gestation. Changes in maximal tension induced by potassium chloride were measured in arterial sections with intact endothelium. Sections were treated with 3‐morpholinosydomine (SIN‐1), which releases O2* and NO simultaneously, with or without pre‐treatment either with hemoglobin (3 μM) or melatonin (0.1–10 μM). SIN‐1 produced a significant dose‐dependent relaxation of vascular tension. Pre‐treatment with hemoglobin did not affect SIN‐1‐induced relaxation. Melatonin significantly reduced the vasorelaxant effect of SIN‐1 in a concentration‐dependent manner. These findings indicate that ONOO‐ attenuates vascular tension in the human umbilical artery. Melatonin significantly suppressed the vasorelaxant effect of SIN‐1, possibly due to its ability to scavenge ONOO‐
Urinary 6‐sulfatoxymelatonin excretion and aging: New results and a critical review of the literature
Authors: Kennaway David J. , Lushington Kurt , Dawson Drew , Lack Leon , van den Heuvel Cameron , Rogers Naomi
Published: February 2007

Abstract: The apparent age‐related decline in melatonin production has been thought to continue in a secular manner across the lifespan. While it is clear that melatonin levels in children and adolescents are elevated compared to older individuals, the question of whether there is a sudden or gradual change has not been adequately addressed. In this study, we report the excretion of the melatonin metabolite, 6‐sulfatoxymelatonin in 253 subjects aged between 21 and 82 yr. The correlation with age was significant (r= ‐ 0.24; P < 0.05). When the data was analysed by ANOVA using 5‐yr age spans, there was a significant effect of age, but post hoc analysis indicated that after 25 yr of age there was no significant decline in excretion of the metabolite. Thus, although the oldest subjects excreted 36% less melatonin metabolite than the youngest, the decrease occurred at a very early age. In the second part of the study, we re‐evaluated the data from seven previous studies that measured plasma melatonin levels or metabolite excretion across a wide range of ages and 11 studies comparing young versus older subjects. Statistical analysis by ANOVA again suggested that the changes in melatonin occurring with age were essentially complete before 30 yr of age. The youngest subjects produced at the most twice the amount of melatonin as the oldest subjects. Finally, we evaluated the mean plasma melatonin levels in 144 groups of normal subjects reported in 137 separate publications with respect to age. Again, whereas there was a significant correlation with age, ANOVA showed that there was no difference between groups after 35 yr of age, and the oldest groups had levels that were only 43% of the youngest groups. We conclude that melatonin production is lower in older people, but that the change occurs very early in life, around 20–30 yr of age.
Evaluation in humans of the effects of radiocellular telephones on the circadian patterns of melatonin secretion, a chronobiological rhythm marker
Authors: de Seze René , Ayoub Jean , Peray Pascale , Miro Luis , Touitou Yvan
Published: February 2007

Abstract: A decrease in melatonin secretion has been observed in small mammals under exposure to extremely low frequency electromagnetic fields. As there is some concern about possible health effects of the increasing use of radiocellular telephones emitting radiofrequency electromagnetic fields, we examined whether such fields would alter melatonin levels in the human. Volunteers were two groups totalling 38 men, 20–32 yr old. Exposures were to commercially available cellular telephones of the GSM 900 type (Global System for Mobile communication at 900 MHz) or DCS 1800 type (Digital Communication System at 1800 MHz), for 2 hr/day, 5 days/wk, for 4 wk, at their maximum power. Attention of the volunteers was sustained by TV projection of movies. Blood samples were collected hourly during the night and every 3 hr in the daytime. Four sampling sessions were performed at 15‐day intervals: before the beginning of the exposure period, at the middle and the end of the exposure period, and 15 days later to evaluate the persistence or late appearance of potential effects. Evaluated parameters were the maximum serum concentration, the time of this maximum, and the area under the curve of the hormone profile. Melatonin circadian profile was not disrupted in 37 young male volunteers submitted to a typical pattern of exposure to the electromagnetic fields generated by two common types of cell phones.
Transepidermal water loss after photodynamic therapy, UVB radiation and topical corticosteroid is independent of inflammation
Authors: Faurschou Annesofie , Wiegell Stine Regin , Wulf Hans Christian
Published: February 2007

Background/purpose: Photodynamic therapy (PDT) and ultraviolet radiation cause an inflammatory reaction of the skin. This may lead to disruption of the skin barrier function. We examined the acute effect of PDT and short‐wave ultraviolet radiation (UVB) on the barrier function of the epidermis. Furthermore, we explored the effect on the skin barrier of topical corticosteroid previous to UVB exposure.

Methods: Eight patients with acne vulgaris of the face were treated with PDT two times, and eight patients were left untreated. The transepidermal water loss (TEWL) was measured before treatment and at three control visits after PDT over 12 weeks. Twenty healthy volunteers were irradiated with UVB in two areas on the back. One area was treated with topical high‐potency corticosteroid before irradiation. TEWL was measured before, 15 min and 24 h after UVB exposure.

Results: TEWL did not differ significantly between the various visits in each acne group and no significant difference in the TEWL between PDT‐treated patients and the control group was found at any visit (P>0.05). TEWL was not significantly altered 15 min and 24 h after a single exposure to UVB and no positive relationship was found between UV‐induced erythema and change in TEWL (P>0.05). Application of topical corticosteroid before UVB did not affect the skin barrier function significantly (P>0.05).

Conclusion: Neither PDT nor a single exposure to UVB damaged the permeability barrier function of the skin and no effect on the TEWL was found when topical corticosteroid was applied previous to UVB irradiation.
Factors Influencing the Green Body Properties and Shrinkage Tolerance of LTCC Green Tapes
Authors: Besendörfer Georg , Roosen Andreas , Modes Christina , Betz Thomas
Published: February 2007

Low‐temperature co‐fired ceramics (LTCC) is a powerful technology for the manufacture of integrated electronic devices. To fulfill the needs of miniaturization, the applied materials must be of constant quality and the manufacturing processes must be well controlled. The reproducibility in shrinkage is one of the most important quality issues of LTCC tapes. To guarantee the customer a narrow shrinkage tolerance, the tape producer must know the important influencing factors of tape manufacturing on shrinkage. In this work, the effects of slurry composition, tape‐casting parameters like casting speed and opening of the blades, and tape handling on the sintering shrinkage behavior were investigated by using design of experiments. The investigation showed that the green density and therefore the shrinkage values of tapes depend considerably on the variation of the solvent mixture. Furthermore, significant interactions were quantified between the tape‐casting velocity as well as the particle size and the shrinkage behavior. The shrinkage values were also influenced by mechanical deformations of the tapes before firing.
First stars as a possible origin for the helium-rich population in ω Cen
Authors: Choi Ena , Yi Sukyoung K.
Published: February 2007

The most massive Galactic globular cluster ω Cen appears to have two, or perhaps more, distinct main sequences. Its bluest main sequence is at the centre of debate because it has been suggested to have an extremely high helium abundance of Y ∼ 0.4. The same helium abundance is claimed to explain the presence of extreme horizontal branch stars of ω Cen as well. This demands a relative helium-to-metal enrichment of ΔY/ΔZ ∼ 70; that is, more than one order of magnitude larger than the generally accepted value. Candidate solutions, namely asymptotic giant branch stars, massive stars and supernovae, have been suggested; but in this study, we show that none of them is a viable channel, in terms of reproducing the high value of ΔY/ΔZ for the constrained age difference between the red and blue populations. Essentially no populations with an ordinary initial mass function, including those candidates, can produce such a high ΔY/ΔZbecause they all produce metals as well as helium. As an alternative, we investigate the possibility of the stochastic ‘first star’ contamination to the gas from which the younger generation of ω Cen formed. This requires the assumption that the Population III star formation episode overlaps with that of Population II. While the required condition appears extreme, very massive objects in the first star generation provide a solution that is at least as plausible as any other suggestions made before.
HEAT AND MASS TRANSFER FUNDAMENTALS APPLIED TO FOOD ENGINEERING1
Authors: KING C. JUDSON
Published: February 2007

There is a need for deeper qualitative and quantitative understanding of the heat and mass transfer mechanisms underlying various techniques for food production, processing, preservation and storage. This is important for the development of new food sources, for more economical and energy‐efficient processing of food from existing sources, for better food quality and quality control, and for adherence to new regulations such as nutritional labeling and shelf‐life dating.

Several classes of food‐processing problems are presented where advances can be made on the basis of improved understanding of heat and mass transfer mechanisms. These include cases of competing transport, cases where transport competes with kinetics of chemical or biochemical reactions, and cases where determination and understanding of the rate‐determining factor are needed. Specific examples are drawn from drying processes, leaching and extraction, freezing, sterilization and enzyme deactivation, and artificial cultivation.
COMPACTION BEHAVIOR OF BULK WHOLE CORN KERNEL AT PRESSURES UP TO 34.6 MN/m2
Authors: MCNULTY P. B. , MOHSENIN N. N.
Published: February 2007

The compaction behavior of whole corn kernel (1.8–22.0% mc, w. b.) was investigated by axial compression in an 18.5 mm diameter die using the Amatek Universal Testing Machine at 28°C. The maximum applied pressure in each experiment was 34.6 MN/m2 at loading rates of 0.028, 0.28, and 2.8 mm/s. Sample failure due to oil expression or sample extrusion did not occur in any test run. However, extensive physical rupture of corn kernels occurred at 1.8% moisture content and at lesser but significant levels at 6.6 and 9.7% moisture. At 15.9 and 22.0% moisture, samples were plastically deformed but little macroscopic kernel damage was evident. The effectiveness of compaction increased dramatically as moisture content increased up to 22.0% and then appeared to gradually decline with further increase in moisture. The average compression ratio at zero pressure varied from an average low of 1.70 at 1.8% to an average high of 1.92 at 22.0% mc corresponding to reductions in corn volume of 41 and 47%, respectively. In contrast, loading rate had little effect on density‐pressure profiles. The latter were not adequately characterized by powder compaction models reported in the literature. Substantial volumes of internal tissue gas were estimated with an average maximum of 21% in 15.9% moisture corn kernels.

The extent of stress relaxation after termination of compaction increased as loading rate increased and was highest in 15.9% moisture corn. The pressures required for the ejection of compacted corn from the 18.5 mm die varied from 0.5 to 2.1 MN/m2 and revealed an average maximum value at 9.7% moisture. Ejection pressures were substantially independent of loading rate. The most stable compacted corn samples were those produced at the 15.9% moisture level although the compact stability in general was very poor indeed.
ANALYSIS AND ECONOMIC EVALUATION OF CONCENTRATION ALTERNATIVES FOR LIQUID FOODS — QUALITY ASPECTS AND COSTS OF CONCENTRATION
Authors: THIJSSEN H.A.C. , VAN OYEN N.S.M.
Published: February 2007

In the selection of concentration processes the net added value of the concentrate with respect to the capital invested should be maximized. The net added value expressed per unit weight of feed is the difference between the gross added valve, being the increase in product value due to concentration, and the costs of concentration. The main factors affecting the gross added value and the concentration costs are treated systematically.

The main factors influencing the gross added value are: thermal quality degradation by chemical reactions; loss of volatile aromas; and the concentration that is obtained in the process. The first two factors generally affect the gross added value negatively. The thermal effects of the various processes are shortly summarized. In revaporative concentration and reverse osmosis, aromas can usually be recovered by steam stripping and distillation if the aromas in the food are at least a factor of three more volatile than water. For liquids containing aromas with a relative volatility close to or smaller than unity only freeze concentration can be used, if the quality is to be fully retained.

The approximate costs of concentration are given for dewatering capacities in the range of 1 to 50 tons per hour and 2000 to 7000 operational hr per year. As energy costs increase further, only concentration processes with a relatively low energy consumption will, at least for higher capacities, remain economically justified. The energy consumptions expressed in steam equivalents vary widely, viz. evaporation 0.16–1.3, freeze concentration 0.25–0.5, and membrane processes 0.01–0.48.
ENERGY INPUTS FOR PRODUCTION, PACKAGING AND TRANSPORTATION OF WINE
Authors: RAO M. A. , RICE A. C.
Published: February 2007

Energy expenditure for wine during its processing, packaging, and transportation was studied; the study was based on data from a winery in upstate New York for the years 1974–75 and 1975–76. It was found that the following quantities of energy are expended in each of the studied segments per case of twelve 1/5 gal. bottles: winery operation— 6.10 × 104Btu; ingredients and processing aids— 1.34 × 104Btu; packaging materials— 1.76 × 105Btu; and transportation for distribution— 2.78 × 104 Btu. All four segments should be studied for their potential for energy conservation.
THERMAL CONDUCTIVITY OF LIQUID FOODS—A REVIEW
Authors: CUEVAS ROBERTO , CHERYAN MUNIR
Published: February 2007

Theoretical and semi‐empirical models for estimating the thermal conductivity (k) of liquid foods are reviewed. Seven models were considered; five, all containing temperature as an independent variable, were selected for their simplicity and apparent accuracy for further study and statistical evaluation. Experimental k values of 158 food samples, such as fruit and vegetable juices, sugar solutions, egg white and dairy products, were obtained from the literature. The model by Riedel (1949) described the data the best, producing the lowest standard error in the estimation of experimental values. Using thermal conductivity of water would give errors almost four times as much as if the Riedel model was used. These semi‐empirical models could also be used to estimate average k values in processes where temperature and/or solids content were varying. Theories of thermal conductivity applicable to liquid food systems were reviewed.
ENERGY REQUIREMENTS OF BEET COLORANT PRODUCTION
Authors: BLOCK J. E. , AMUNDSON C. H. , VON ELBE J. H.
Published: February 2007

Energy requirements were monitored during the production of a beet colorant on a pilot plant scale. Colorant production involved centrifugation, concentration by fermentation, vaccum concentration, and spray drying. The economic feasibility of adding the fermentation operation to the present extraction and concentration operations was studied. Data were obtained on the production rate, pigment recovery, energy consumption (electrical, steam, gas), and pigment concentration at each unit operation. Calculations were based on a ton of raw beets processed. Energy costs were $15.57 per ton. The final spray dried colorant contained between 3 and 5% pigment depending on raw product quality. Byproducts of yeast and alcohol helped to offset 16% of the energy and raw product costs.
POTENTIAL FOR UTILIZING 11S SOY GLOBULAR PROTEIN TO STUDY TEXTURE FORMATION1
Authors: BRESNAHAN D. P. , WOLF J. C. , THOMPSON D. R.
Published: February 2007

A corn meal based model food system was successfully utilized in experiments designed to measure the influence of protein type on product integrity. The food systems were processed using either a capillary rheometer or an extrusion capillary rheometer to produce the texturized product. The Warner‐Bratzler Shear test and the Ottawa texture measuring tests were utilized to indicate product integrity. The purified 11S soy protein produced a product with greater integrity as measured by maximum shear value than an equivalent amount of soy protein isolate from which it was derived.
ULTRAFILTRATION OF WHOLE MILK WITH HOLLOW FIBER MEMBRANES
Authors: GAROUTTE C. A. , AMUNDSON C. H. , HILL C. G.
Published: February 2007

Whole milk was concentrated using Romicon PM50 membranes. Rententate and permeate were analyzed for total solids, protein (TKN) and fat at five concentration levels. The effects of pressure, concentration, fiber length and several milk pretreatments on flux were examined. A 5X concentrate was prepared containing 37.2% solids, 13.3% protein and 17.8% fat. The highest initial and 4X fluxes were obtained using a pressure differential of 1.4 kg/cm2 ‐ 2.11/0.7 (20 psig ‐ 30/10). Flux declined slowly with concentration to 3X (20% loss) and decreased more rapidly thereafter. Higher fluid velocities were deemed responsible for 27% higher initial flux and 47% higher 4X flux when a shorter module was employed (63.5 versus 109.2 cm). Clarification, pasteurization and/or homogenization had little effect on flux at either level.
HYDRODYNAMICS and HEAT TRANSFER IN LIQUID FULL SCRAPED SURFACE HEAT EXCHANGERS — A REVIEW
Authors: ABICHANDANI H. , SARMA S. C. , HELDMAN D. R.
Published: February 2007

Theoretical and empirical models pertaining to the hydrodynamics and heat transfer in liquid full scraped surface heat exchangers have been reviewed up to date. In hydrodynamics, various aspects viz. fluid flow, residence time distribution, power requirement are covered. the heat transfer characteristics have been reviewed from stand points of heating, cooling and ultra high temperature applications. the limitations of various models are explained. the logical conclusions and the areas needing further investigations have been delineated.
MEASURING the MECHANICAL PROPERTIES of APPLE TISSUE USING MODAL ANALYSIS
Authors: VAN WOENSEL G. , VERDONCK E. , DE BAERDEMAEKER J.
Published: February 2007

Along with the grade of intactness, fruit firmness is an important factor for the quality criteria on which the consumers acceptance for apples is based.

Two methods for measuring the fruit firmness (a destructive one and a nondestructive one) are compared. the nondestructive method uses modal analysis to define the lower vibration modes. This enables the use of the 3‐media elastic sphere model developed by Cooke and Rand (1973) to calculate the dynamic elastic moduli of the whole apples. the destructive method determines the dynamic elastic moduli of cylindrical samples of apple tissue. This method is based on the vibration characteristics of a mass‐spring‐damper system. This system consists of a cylindrical apple sample and a mass. Measuring the direct transfer function of this one‐degree‐of‐freedom system results in values of its system parameters, from which the dynamic elastic moduli of the specimen can be calculated.

The results of the two methods applied on Golden Delicious apples were compared, and the suitability of each model was evaluated.
STUDIES of WATER TRANSPORT PHENOMENA DURING POTATO‐DRYING
Authors: LAMBERG INGRID
Published: February 2007

Sorption isotherms and drying mechanisms of Bintje potatoes have been investigated experimentally. the product temperature and the moisture content was determined during the drying experiments.

A simulation method to estimate the diffusion coefficient and the moisture content profiles for the potatoes was performed by means of a finite‐difference computer program. Experimentally determined moisture contents were compared with calculated for different estimated values of the diffusion coefficient. If the diffusion coefficient was assumed to be 0.8.10−9 m2/s the correlations were acceptable. the simulated moisture content profiles also gave the surface moisture content.

The surface mass transfer coefficient has been calculated, the resulting β values were in the range of 0.014–0.029 m/s.
OPTIMAL ROASTING
Authors: TOWNSEND M.A. , GUPTA S. , PITTS W.H.
Published: February 2007

In this paper we discuss the application of numerical optimization techniques to the process of roasting, which essentially is heat treating meat under a variety of ambient temperature conditions. the doneness of roast, as measured by the distribution of maximum temperatures achieved through the meat, is taken to be the objective for optimization, using cooking temperatures and times as the process variables. Cooking beef roasts of varying weights and shapes are the examples considered. Additional considerations for optimization, such as minimum cooking time and energy used, have also been considered. Direct search methods were found to be most suited for objective functions with a highly varied topology, as were encountered in this problem. the optimal results, compared with the conventional cooking recommendations, show that superior heat treatment can be effected by using numerical modeling and optimization techniques.
PIGMENTS MODIFICATIONS DURING FREEZING and FROZEN STORAGE of PACKAGED BEEF
Authors: LANARI M.C. , BEVILACQUA A.E. , ZARITZKY N.E.
Published: February 2007

Muscle pigment modifications during freezing and frozen storage of beef wrapped in high (polyethylene) and low (EVA/SARAN/EVA) gaseous permeability films were analyzed. Myo (Mb), oxy (MbO2) and metmyoglobin (MetMb) concentrations were determined using reflectance spectrophotometry. Results indicated that in polyethylene wrapped samples myoglobin oxygenation took place during freezing and the only reaction observed throughout frozen storage was MetMb production from MbO2. Autoxidation was interpreted as a first order kinetic reaction. Storage temperature effect on kinetic and equilibrium constants was analyzed; reaction enthalpy and activation energy were calculated. MbO2 and MetMb production during beef oxygenation was represented as a consecutive first order reaction system determining previous vacuum storage time and temperature influence on oxygenation capacity. Vacuum packaging of frozen beef increased color stability maintaining MetMb concentration levels lower than those corresponding to just frozen samples wrapped in polyethylene.
MODELLING of the MEDIA‐SIDE HEAT TRANSFER IN SCRAPED SURFACE HEAT EXCHANGERS
Authors: HÄRRÖD MAGNUS
Published: February 2007

The heat transfer on the media‐side and in the tube wall of scraped surface heat exchangers was investigated when the product was heated with steam or cooled with water.

The heat transfer coefficients found experimentally were 15% higher than predicted with the Nusselt theory for steam condensation, and 30% lower than predicted with a traditionally recommended model for cooling with water. New, much better models for the media‐side heat transfer were developed. the choice of model for the media‐side affects a subsequent modelling of the heat transfer on the product‐side.

When the product‐flow was laminar in the scraped surface heat exchangers, the heat transfer was controlled mainly by the resistance on the product‐side; while the resistance on the media‐side was very small. Vortical flow decreased the resistance on the product‐side considerably and made the choice of material in the tube wall important from a heat transfer point of view.
TEMPERATURE VARIATIONS IN the OUTLET FROM SCRAPED SURFACE HEAT EXCHANGERS
Authors: HÄRRÖD MAGNUS
Published: February 2007

The radial temperature differences and the stability of the temperatures in the product outlet from scraped surface heat exchangers (SSHE) have been investigated over wide ranges of operating conditions.

When the flow was vortical, the temperature were stable and no radial differences occurred.

When the flow was laminar, channelling effects occurred. the radial temperature differences of the outlet from SSHEs were sometimes very large. the flow was unstable; this was most obvious from the temperature variations close to the blades. In some cases the central parts of the product passed straight through the SSHE without being heated or cooled.

Thus, efficient mixing of the product after the SSHE is of primary importance in many applications with high‐viscosity products, e.g., aseptic processing, or the modelling of the performance of SSHEs.

A static mixer after the SSHE eliminated the radial temperature differences, but in some cases unstable temperatures remained after the mixer due to unstable flow conditions in the SSHE. the degree of stability was influenced by the design of the SSHE and by the flow rate.
GELATION KINETICS of MEAT EMULSIONS CONTAINING VARIOUS FILLERS DURING COOKING
Authors: CORREIA L. R. , MITTAL G. S.
Published: February 2007

A cylindrical shaped thermal scanning rigidity monitor (TSRM) was developed to determine shear rigidity modulus of meat batters during cooking. A meat fatprotein ratio of 1.8, moisture content of 62% and 8.6% filler were used. the fillers were buttermilk powder, corn starch, micro‐crystalline cellulose, modified corn starch, modified wheat flour, soy‐protein concentrate and whey‐protein concentrate. Plots of rigidity modulus versus product‐temperature showed two major thermal transitions. the first and most important transition (53 to 61°C) was due to myosin gelation. the second transition (64 to 69°C) was ascribed to the collagen softening. the maximum rigidity‐temperature slopes of 0.60 to 1.02 kPa/°C occurred after the first transition.