bluuebunny/crossref_metadata_2025_split huggingface dataset:
Melatonin Inhibits the Basal and TSH‐Stimulated Mitotic Activity of Thyroid Follicular Cells In Vivo and in Organ Culture
Authors: Lewiński Andrzej , Sewerynek Ewa 
Published: February 2007

The aim of the present study has been to examine the effect of melatonin, administered to mice as daily subcutaneous injections for a total of 10 days, on the mitotic activity of thyroid follicular cells (TFC). The colchicine metaphasearrest technique was employed in the experiment. We found that melatonin (10μg and/or 100μg injection) decreased significantly the mean mitotic activity rate (MMAR) of TFC in both male and female mice. Moreover, melatonin totally suppressed the stimulatory effect of TSH on the MMAR of TFC in both sexes of mice.Furthermore, the effect of melatonin (5 × 10−7 M) on the proliferation of TFC in the organ‐cultured rat and mouse thyroid explants was investigated. It was found that melatonin almost totally suppressed the MMAR of TFC in organ culture. Moreover, melatonin blocked the stimulatory effect of TSH on the MMAR of TFC in both rat and mouse thyroid explants. N‐acetylserotonin (NAc‐5HT, 10−6 M) also decreased the MMAR of cultured thyroid explants, but its effect was less expressed when compared to melatonin inhibition.The present data indicate that melatonin can exert its inhibitory effect on the proliferation of TFC directly at the thyroid level, since this pineal indoleamine has been shown to suppress not only basal but also TSH‐stimulated mitotic activity.The results are in agreement with the hypothesis of a pineal‐thyroid negative feedback, assuming the direct inhibitory effect of melatonin on the thyroid growth.
Fluctuation of Blood Melatonin Concentrations With Age: Result of Changes in Pineal Melatonin Secretion, Body Growth, and Aging
Authors: Pang S. F. , Tsang C. W. , Hong G. X. , Yip P. C. Y. , Tang P. L. , Brown G. M. 
Published: February 2007

Melatonin in the systemic circulation of rats fluctuates with age, and the causes for such changes were investigated. Male rats (aged 7 days, 16 days, 18 days, 20 days, 30 days, 48 days, 60 days, and > 17 months) were adapted under a lighting regime of 12L: 12D for at least 7 days. Pineals and blood samples from the trunk or confluens sinuum were collected in the dark period. Melatonin in tissues was extracted, identified, and determined by gas chromatography‐mass spectrometry (GC‐MS) and/or radioimmunoassay. Tissue melatonin levels obtained by radioimmunoassay correlated closely with those quantified by GC‐MS. Thus, the melatonin radioimmunoassay used is a reliable assay method for melatonin in the plasma and pineal of the rat.Plasma melatonin in the confluens sinuum of rats exhibited episodic release superimposed on a basal release pattern. It was suggested that there are two pools of melatonin in the pineal gland, a readily releasable pool and a bound pool. The mean plasma levels of melatonin in the confluens sinuum of rats increased with age with the highest level recorded at 60 days old and declined to a lower level at > 17 months old. The above age‐related changes, being similar to the alterations in pineal melatonin levels with growth and aging, suggest that, under our experimental conditions, levels of pineal melatonin increase or decrease with its secretory rate.In developing rats, the age‐related increase in the rate of secretion of pineal melatonin as reflected by increases in melatonin levels in the confluens sinuum or pineal melatonin content before adulthood is different from the changes in melatonin levels in the systemic circulation which showed an early developmental rise, followed by an active period and then a prepubertal decline. However, when the body weight was taken into consideration, changes in the levels of pineal melatonin content per 100 gm body weight or the calculated blood melatonin levels (plasma melatonin in the confluens sinuum/body:head ratio) correlated well with the fluctuation of serum melatonin in the systemic circulation. Thus, the developmental changes in the concentrations of melatonin in the general circulation are the result of 1) changes in the rate of pineal melatonin secretion and 2) increase in the dilution factor because of increase in body size. In old rats, levels of plasma melatonin in the confluens sinuum and pineal melatonin content decreased indicating a decline in the rate of pineal melatonin secretion. These results suggest that the reduced level of systemic melatonin in aged rats is the result of a decline in the rate of pineal melatonin secretion plus an increase in the body weight.
Effect of a 15 minute light pulse on nocturnal serum melatonin levels in human volunteers
Authors: Petterborg L. J. , Kjellman B. F. , Thalén B. E. , Wetterberg L. 
Published: February 2007

Petterborg LJ, Kjellman BF, ThalQ BE, Wetterberg L. Effect of a 15‐minute light pulse on nocturnal serum melatonin levels in human volunteers. J Pineal Res 1991:10:9‐13.Abstract:Monitoring the daily melatonin rhythm during the course of phototherapy for affective disorders may be beneficial in assessing the efficacy of such treatments. It is therefore of interest to study the effects of the timing, duration, and intensity of bright light pulses on melatonin levels in normal subjects. To examine the effects of a single exposure to a brief burst of bright light on serum melatonin, groups of healthy human volunteers of both sexes were treated with a 15 minute pulse of bright light (350 cd/m2) early in the evening during the winter months. Serial blood samples were collected from each person and the effect of the light pulse on serum melatonin and cortisol levels determined.Melatonin levels were significantly but only transiently suppressed by the light pulse, while cortisol levels were not affected. These results demonstrate that short duration bright light treatments can influence the melatonin rhythm generating system in humans.
Participation of the pineal gland in sexual maturation of female rainbow trout (Oncorhynchus mykiss Walbaum)
Authors: Popek Wlodzimierz , Bieniarz Krzysztof , Epler Piotr 
Published: February 2007

Abstract: In the study rainbow trout, pinealectomized at two different periods of their sexual cycle, i.e., at either 1 or 5 months before spawning, were studied. It was found that the lack of the pineal gland in the period directly preceding the spawning had no statistical effect on either spawning or the number of females that produced eggs.Pinealectomy performed during vitellogenesis delayed spawning by about 2 weeks and resulted in the absence of ovulation in 20% of the females. The results suggest that the pineal gland may influence the hypothalamo‐pituitary‐gonadal axis by altering the maturation period and controlling spawning in the rainbow trout.
Melatonin concentrations in pineal organ culture are suppressed by sera from tumor‐bearing mice
Authors: Leone A. M. , Skene D. 
Published: February 2007

Leone AM, Skene D. Melatonin concentrations in pineal organ culture are suppressed by sera from tumor‐bearing mice. J. Pineal Res. 1994: 17: 17–19.AbstractThe melatonin rhythm is significantly attenuated in a wide range of human and animal tumor types. Since surgical removal of the tumor has been shown to restore this rhythm, we hypothesized that a plasma borne tumor‐associated factor (TAMF) could be responsible. A population of mice were injected with tumor cells and sequentially killed and bled over the following 9 days, i. e., to the maximal state of tumor growth. Pooled serum from the different collection days was added to an established pineal organ culture system, and melatonin concentrations measured. A highly significant correlation between melatonin concentrations and the stage of tumor growth was seen with maximal inhibition occurring at day 9 (P < 0. 01). These findings support our hypothesis and may help to explain the mechanism whereby melatonin rhythmicity is suppressed in cancer patients.
Melatonin modulates growth factor activity in MCF‐7 human breast cancer cells
Authors: Cos Samuel , Blask David E. 
Published: February 2007

Cos S, Blask DE. Melatonin modulates growth factor activity in MCF‐7 human breast cancer cells. J. Pineal Res. 1994: 17: 25–32.AbstractMelatonin has been shown to have direct oncostatic actions on estrogen‐responsive, MCF‐7 human breast cancer cells in culture. In the present study, we examined whether these inhibitory actions on cell growth may be mediated through actions on bioassayable growth factor activity. In order to test this hypothesis, we estimated the growth factor activity of conditioned medium (CM) from estradiol (E2), or melatonin‐treated cells, in the presence or absence of melatonin on MCF‐7 cell growth. We also determined whether melatonin inhibits the action of epidermal growth factor (EGF) action in the absence of E2. The addition of melatonin (10‐9 M) to the cultures of MCF‐7 cells with CM from E2 (10‐8 M)‐treated cells significantly inhibited the growth stimulatory activity of CM, suggesting that melatonin inhibited cell proliferation by blocking the action of E2‐induced autocrine growth stimulatory factors. Conditioned medium from melatonin‐treated cells significantly inhibited cell proliferation, while an additional supply of melatonin to these cultures had an even greater inhibitory effect. Melatonin was also active in the complete absence of serum as long as cell growth was stimulated by EGF, an E2‐inducible growth factor. The inhibitory effect of melatonin increased as the dose of EGF increased. This non‐antiestrogenic inhibitory effect of melatonin was reversed by E2, but not by EGF itself, suggesting that melatonin requires accessible estrogen receptor sites for its inhibitory activity on the growth stimulating action of EGF. Taken together, these findings suggest that melatonin may inhibit the action and/or release of growth stimulatory factors as well as stimulate the release of growth inhibitory factors in culture. Furthermore, these findings indicate an important interaction of melatonin with E2‐inducible autocrine growth factors such as EGF in the inhibition of MCF‐7 cell growth.
Clarifying plasma melatonin profiles in domestic pigs: A critical and comparative evaluation of two radioimmunoassay systems
Authors: Klupiec Corinna , Evans Gareth , Love Robert J. , Kennaway David J. 
Published: February 2007

Klupiec C, Evans G, Love RJ, Kennaway DJ. Clarifying plasma melatonin profiles in domestic pigs: A critical and comparative evaluation of two radioimmunoassay systems. J. Pineal Res. 1997; 22:65–74. © Munksgaard, Copenhagen.AbstractThe results of a direct radioimmunoassay (RIA) for porcine plasma melatonin, suggesting a relationship among plasma melatonin, feed intake and photoperiod, were investigated by comparison with the results of an extracted RIA. These findings were further examined by analysis of a small number of samples using gas chromatography‐mass spectrometry (GCMS). The results identified inadequacies in the specificity of the direct RIA and failed to provide evidence for an effect of feed intake on melatonin secretion. Instead, it appeared that feed restriction exacerbated nonspecificity in the direct RIA. The cause of nonspecificity, and its effect on analysis of daily plasma melatonin profiles, were examined. The plasma component(s) responsible for nonspecificity was (were) not identified. However, the results suggest that characteristics of the antiserum used in the direct RIA are involved in the mechanism by which nonspecificity is induced. Results obtained using the extracted assay revealed that plasma melatonin concentrations in prepubertal gilts and pregnant sows exhibit a diurnal pattern, in which concentrations are low during daylight and modestly increased during darkness. Using the direct RIA, the same profiles exhibited highly variable melatonin concentrations showing little association with the light‐dark cycle. Thus, assay specificity was identified as a factor contributing to inconsistencies in the literature describing plasma melatonin in the domestic pig and the importance of rigorous validation of RIAs was demonstrated. Furthermore, the results indicate that plasma melatonin concentrations in domestic pigs, as in other mammalian species, are entrained by the light‐dark cycle.
A note on the time dependence of pineal gland research publications
Authors: Graham Daniel J. , McNulty John A. 
Published: February 2007

Graham DJ, McNulty JA. A note on the time dependence of pineal gland research publications. J. Pineal Res. 1997; 23:59–62. ©Munksgaard, CopenhagenAbstractCounts of the number of publication titles containing the search truncation “pinea*” were compiled via Current Contentsover the time period 1978–1994. These counts and their time dependence were examined for autocorrelations and frequency spectral components. Such analyses were carried out irrespective of either author, research laboratory, funding, or other factors. Interestingly, the results show the research publication rate in pineal studies to be linked to community history. In particular, the interactions affecting output among community members operate on a few characteristic time scales ranging from one to several years.
Melatonin prevents β‐amyloid‐induced lipid peroxidation
Authors: Daniels W.M.U. , van Rensburg S.J. , van Zyl J.M. , Taljaard J.J.F. 
Published: February 2007

Daniels WMU, van Rensburg SJ, van Zyl JM, Taljaard JJF. Melatonin prevents β‐amyloid‐induced lipid peroxidation. J. Pineal Res. 1998; 24:78–82. © Munksgaard, CopenhagenAbstractβ‐Amyloid is a major constituent of senile plaques that occur in the brains of Alzheimer's disease (AD) patients. Cell culture studies have shown that high concentrations of β‐amyloid are toxic and damage biological macromolecules. A number of experiments have shown that melatonin is a potent antioxidant. Melatonin not only neutralizes oxygen‐derived free radicals but can also scavenge species of other types such as carbon‐centered free radicals. The present study was designed to determine whether P‐amyloid toxicity would cause lipid peroxidation of human platelet membranes. Since aluminum has been implicated in the etiology of AD, we investigated the effects of aluminum on lipid peroxidation and whether the harmful effects of β‐amyloid are aggravated by aluminum. We also investigated whether melatonin had the ability to protect against (3‐amyloid toxicity. Our results indicate that both β‐amyloid and aluminum dose‐dependently increased lipid peroxidation in platelet membranes. Aluminum was more potent than β‐amyloid. Incubation of platelet membranes with increasing concentrations of aluminum in the presence of 100 μM β‐amyloid (fragment 25–35) resulted in lipid peroxidation levels of similar magnitude as the two substances, respectively. Prior administration of melatonin dose‐dependently inhibited this effect. These results confirm the toxic effects of β‐amyloid to biological membranes. While aluminum itself damages membranes, its presence did not exacerbate the toxic effects of β‐amyloid. Melatonin effectively reduced the lipid peroxidation induced by β‐amyloid and aluminum, suggesting that its supplementation to AD patients may be beneficial.
Properties of pressure‐sensitive adhesive tapes with soft adhesives to human skin and their mechanism
Authors: Tokumura Fumio , Homma Takeyasu , Tomiya Toshiki , Kobayashi Yuko , Matsuda Tetsuaki 
Published: February 2007

Background/purpose: The use of soft adhesives in the manufacture of pressure‐sensitive adhesive tapes has recently increased. The dermal peeling force of adhesive tapes with soft adhesives was studied.Methods: Four kinds of adhesive tapes with adhesives of different softness were made, by adding varying amounts of isopropyl myristate as a softener. The tapes were applied on the flexor side of the forearm of six healthy male volunteers. The dermal peeling force, the amount of stripped corneocytes, the level of pain when the tapes were removed and the degree of penetration of adhesives into the sulcus cutis (skin furrows) were evaluated at 1 and 24 h after application of the tapes. Furthermore, a skin model panel (a sulcus cutis and crista cutis model panel) and a crista cutis model panel were constructed from a general stainless‐steel panel, and the peeling force of the tapes against the model panels was measured.Results and conclusion: As the softness of adhesives increased, the peeling force against a general stainless‐steel panel with a flat surface decreased, although the peeling force against human skin did not significantly change. The amount of stripped corneocytes on the removed tapes and the level of pain when the tapes were removed decreased with the increase in softness of the adhesives. These results suggest that adhesive tapes with soft adhesives that contain isopropyl myristate as a softener are suitable for the skin. Furthermore, the degree of penetration of adhesive into the sulcus cutis increased as the softness of adhesives increased. Upon evaluation of the peeling force against the model panels, as the softness of adhesives increased, there was a slight decrease in the peeling force against the skin model panel, while there was a remarkable decrease in the peeling force against the crista cutis model panel. These results suggest that the lack of change in the dermal peeling force as the softness of adhesives increased was caused by penetration of soft adhesive into the sulcus cutis, and that the decrease in the amount of stripped corneocytes was caused by a decrease in the peeling force against the crista cutis, which consists of corneocytes mainly removed by the tapes.
Bipolar ejection by the symbiotic binary system Z And during its 2006 outburst
Authors: Tomov N. A. , Tomova M. T. , Bisikalo D. V. 
Published: February 2007

Abstract
High-resolution data in the region of the Hα line have been obtained at the time of light maximum and after it for the 2006 optical outburst of the symbiotic binary Z And. A blueshifted absorption component indicating an outflow velocity of about 1400 km s−1, as well as additional emission components with similar velocities, situated on the two sides of the main peak of the line, were observed during that time. It is suggested that all of them are spectral signatures of bipolar outflow, observed for the first time in the optical spectrum of this binary. The emission measure and the mass of the nebular part of the streams have been estimated approximately, reaching values of up to about 6 × 1057 cm−3 and 8 × 10−8 M⊙.
MEASUREMENT OF THERMAL CONDUCTIVITY OF DAIRY PRODUCTS AND MARGARINES
Authors: SWEAT VINCENT E. , PARMELEE CARLTON E. 
Published: February 2007

ABSTRACTA line heat source thermal conductivity probe was used to measure the thermal conductivity of 28 dairy products and margarines at 0, 20, and 40†C. Water and fat contents and mass density of each sample were also measured and correlated to thermal conductivity.There was a strong positive correlation between thermal conductivity and water content, and an inverse correlation between thermal conductivity and fat content. Temperature did not appear to be a significant factor over the limited temperature range studied. Although there was some correlation between mass density and non‐fat solids fraction, no correlation was observed between mass density and thermal conductivity.
RHEOLOGICAL BEHAVIOR OF ULTRA‐HIGH TEMPERATURE STEAM INJECTED DAIRY PRODUCTS ON AGING1
Authors: SWARTZEL K.R. , HAMANN D.D. , HANSEN A.P. 
Published: February 2007

ABSTRACTMilk (0.5, 3.25, and 10.5% fat) was processed in an ultra‐hightemperature steam injection system. Process time‐temperature relationships included 138, 143, and 149°C for 20.3s; 143 and 149°C for 6.9 s; and 149°C for 3.4 s. Product from each run was stored at 4, 24, and 40°C Using four commercial viscometer assemblies the flow behavior constants of the power‐law equation were determined for each treatment through 60 weeks of storage. Regression analysis of the calculated power law constants resulted in a graphical summary of the history of flow properties for each treatment.Age‐thickening (gelation) was found to be associated with process residence time, storage temperature, storage time, and fat level. Process temperature was not a significant factor. The shorter the residence time the faster gelation occurred. The earlier a sample gelled the faster its rate of gelation. For a given residence time, gelation developed first in samples of low percent fat and progressed through higher fat contents.A gelation prediction nomograph based on fat level, residence time, and storage time is presented for a 24°C storage temperature.
RHEOLOGICAL MODELING OF UHT MILK GELS USING A CONE AND PLATE CREEP‐RELAXATION TEST1
Authors: SWARTZEL K.R. , HAMANN D.D. , HANSEN A.P. 
Published: February 2007

ABSTRACTThe gelation of UHT steam injected dairy products was investigated by determining rheological model constants. Fat percentages of the products were 0.5, 3.25 and 10.5. Each product was processed at 143 °C for 6.9 s and stored at 24 °C. At four week intervals, from 55 to 85 weeks storage, cone and plate creep‐relaxation data was collected Three element rheological models were developed for each test date. Empirical relationships were derived relating the elastic and viscous constants to storage time for each fat content. The strongest parameter for all samples was the series elastic constant. The viscous constant was next with the Kelvin elastic constant being much weaker. All constants for all samples increased over storage time as gelling progressed (apparent viscosity increased). The lower the percent fat, the sooner gelling started and the faster the rate. The gelation of UHT milk was examined and found to depend heavily on the percent fat.
MULTIPLE SIEVE SIFTER PERFORMANCE USING VARIOUS COMBINATIONS OF FEED RATES, CIRCLES AND SPEEDS1
Authors: Wingfield John , Ferrer Alonso 
Published: February 2007

ABSTRACTWheat was ground on a rollermill then sifted into several size classifications to determine how certain sifting characteristics changed when the material was subjected to changes in feed rate, sifter circle or throw and sifter speed.The travel speed of the stocks over the sieves decreased with a decrease in average particle size. Changes in the rate of feed to the sieves had no effect on the stock travel time. Travel speed was increased for all stocks when the linear cloth speed of the sieve was increased.Sifter efficiency, as defined by the percent of undersize material removed by each sieve in a series of sieves having the same cloth aperture, compared to the amount of undersize material going to the first sieve of the series was influenced by changes in feed rates and in sifter dynamics.Particle size analysis of individual sieve throughs showed that when the stocks were sifted on a series of sieves having the same aperture opening size, the finest material was sifted out on the first sieve with subsequent sieve throughs becoming progressively coarser.
CONSIDERATIONS IN CALCULATING KINETIC PARAMETERS FROM EXPERIMENTAL DATA
Authors: ARABSHAHI ABOLFAZL , LUND DARYL B. 
Published: February 2007

ABSTRACTEngineers require quantitative models to design and optimize processes. In the food industry, these process models become very complex because of the unique physical/chemical characteristics and variability of the raw material. Furthermore, frequently data describing rates of reactions and/or changes in foods are generated by food scientists who are not thoroughly familiar with reaction models. Analysis of those data to obtain parameters for reaction models thus becomes critical. In this paper, calculating kinetic parameters from experimental data is examined, and suggestions are presented for determining reaction rates and temperature dependence.