bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving minority blood donation: anthropologic approach in a migrant community
Authors: Grassineau Dominique , Papa Kassim , Ducourneau Axel , Duboz Priscillia , Boëtsch Gilles , Chiaroni Jacques
Published: February 2007

BACKGROUND:As a result of blood group polymorphism, distinctive blood types have evolved in populations around the world. In countries with large migrant populations, finding rare blood types for transfusion can be challenging. This is especially true for sub‐Saharan African immigrants living in countries with predominantly European populations. This problem is further compounded by hereditary disorders such as sickle cell disease and by traditional cultural values that discourage routine donation.

STUDY DESIGN AND METHODS:The purpose of this report is to describe the drive to recruit more safe rare blood type donors in a Comorian immigrant community living in Marseilles, France. With a culturally adapted message developed on an anthropologic approach and working in close collaboration with scientific and medical members of the Comorian community, it is proposed that this population be sensitized with the gift of blood.

RESULTS:Targeted collection of specific sub‐Saharan African blood types was achieved. Taking into account the high rate of infectious markers among products collected in this targeted collection, however, it was decided to promote blood donation in this minority by addressing people directly toward our principal blood center site. Since setup of this adapted communication, regular donors present themselves spontaneously without community pressure. Infectious markers rate is then equal to general blood donor population's rate.

CONCLUSION:The results of this drive demonstrate the utility of an anthropologic approach and cultural mediation in identifying donors with specific blood types in migrant communities and recruiting second‐generation donors. The techniques described in this study could also be applied to collection of other tissues including organs and peripheral blood progenitor cells in minorities.
Herbicide resistance and the adoption of integrated weed management by Western Australian grain growers
Authors: Llewellyn Rick S. , Lindner Robert K. , Pannell David J. , Powles Stephen B.
Published: February 2007

Extension programs to encourage farmers to reduce reliance on herbicides by adopting integrated weed management (IWM) practices have met with limited success. Studies aiming to understand the factors that influence farmers' choices of integrated control practices have faced difficulties in variable specification, and have not achieved high explanatory power. Using data from grain growers in Western Australia, where herbicide resistance in major crop weeds is common, this study tests the applicability of a framework for the IWM adoption decision in which herbicide efficacy is assumed to be a potentially exhaustible resource. Farmers' perceptions of multiple techniques and other variables are aggregated using principal components, and used in logistic regressions to explain the intensity of use of IWM practices. Eighty‐six percent of growers were correctly classified according to use of multiple IWM practices. Herbicide resistance and expectations of the future availability of effective new herbicides were significant in explaining IWM adoption. IWM adoption and herbicide‐resistance management are shown to be information‐intensive and involving an intertemporal resource management decision.
Absence of Nocturnal Plasma Melatonin Surge Under Long and Short Artificial Photoperiods in the Domestic Sow
Authors: McConnell S.J. , Ellendorff F.
Published: February 2007

The circadian plasma melatonin profile of German Landrace sows was determined at 1‐h intervals for 31 h after exposure to each of four different artificial photoperiods. Under 12L:12D, melatonin concentrations in four sows during the light phase ranged from 22 ± 5.9 to 96 ± 25.1 pg/ml (mean ± SEM). During the dark phase (total dark) the individual concentrations increased two‐to fivefold over the peak individual light phase values in three sows. This nocturnal surge was of 3.8 h duration and peaked at 190, 294, and 546 pg/ml at 0100 h, which was 5.5 h after the onset of dark. The surge was abolished in these animals after exposure to 16L:8D and could not be reinstated by the subsequent exposure to 8L:16D. During the latter two photoperiods the mean concentrations were consistently less than the maximum mean value of 30.8 ± 10 pg/ml during the dark phase and 55 ± 21.9 pg/ml during the light phase. All the sows displayed regular estrous cycles during the study, and the day of the estrous cycle on which the samples were obtained under each photoperiod was not significantly correlated with the presence or absence of the nocturnal surge. A separate experiment using different animals confirmed the nocturnal surge under 12L:12D. In two out of four cycling sows the peak concentrations during the dark phase (122 and 110 pg/ml at 0400 and 0500 h) were two‐to sixfold higher than those of the light phase. Absence of the nocturnal surge under long and short daylengths may be a factor contributing to the decline in reproductive performance during the summer and winter months.
The Pineal Gland in Sudden Infant Death Syndrome: Preliminary Observations
Authors: Sparks D. Larry , Hunsaker John C.
Published: February 2007

Sudden infant death syndrome (SIDS) affects infants between 1 month and 1 yr of age, has no known cause, and is diagnosed by exclusion of all other causes of death. The primary mechanism of death in SIDS is considered to be irreversible respiratory cessation during sleep. In a small sampling at necropsy we have observed a statistically significant (P < .005; determined morphometrically) reduction in the anatomic size of the pineal gland in SIDS infants, as compared to age‐matched controls. Whether correspondingly altered pineal glandular function is present in SIDS is as yet unanswered.
Cytodifferentiation of the Chick Pineal Gland, With Special Reference to the Photosensory and Secretory Elements
Authors: Ohshima Koji , Matsuo Shinichi
Published: February 2007

Cytodifferentiation of the chick pineal gland throughout the embryonic development was investigated with light and electron microscopy. The chick pineal anlage appears first as a small evagination in the diencephalic roof at 60 h of incubation (27–30 somites). Until day 5 of incubation, pineal anlage cells are undifferentiated and appear similar to ventricular ependymal cells. Subsequently, pinealocytes and supporting cells are first distinguishable at 7–8 days, and parafollicular cells are distinguishable at 12 days of incubation. Pigment‐containing cells after 6 days and nerve cells after 17 days of incubation gradually increase, especially in the posterior wall of the pineal recess. During embryonic development, the chick pineal gland has both photosen‐sory and secretory elements: viz. the former, mitochondria‐laden apical protrusions, synaptic ribbons, lamellar whorl‐like cilia of the pinealocytes, and adjacent appearance of the pigment‐containing cells and the nerve cells; and the latter, dense‐cored vesicles of the pinealocytes and dense bodies of the supporting cells. Moreover, nuclear invaginations having a large lipid droplet nearby and some aggregations of glycogen are found in the pinealocytes and are transitory changes in structure restricted to certain days of incubation.
Preliminary Evidence for Pineal‐Mediated Extraretinal Photoreception in Relation to Tail Regeneration in the Gekkonid Lizard, Hemidactylus flaviviridis
Authors: Ramachandran A.V. , Ndukuba Patrick I.
Published: February 2007

The tail of the Gekkonid lizard Hemidactylus flaviviridis was autotomized and the animals were subjected to eight different photoperiodic schedules during the process of tail regeneration. Our previous observation had shown that long‐day photoperiods stimulate the regeneration process, whereas short‐day photoperiods depress it. Furthermore, it has also been demonstrated that the lateral eyes, or retinae, do not participate in photoperiodically significant photoreception in H, flaviviridis, as blinded Hemidactylus regenerated their autotomized tails like their sighted counterparts exposed to similar experimental photoregimes. In a further attempt to localize the site(s) of photoreception in these animals, one group of lizards had their heads painted with a mixture of Indian ink and Nile blue sulphate (II‐NBS) [NL (HP)] in order to prevent light from penetrating to the pineal gland, and another group had their pineal glands surgically removed (pinealectomy, Px); the regenerative potentials were compared with their normal (NL) counterparts. Our results showed that the initiation and onset of regeneration, the daily growth rate, the total new growth (regenerate) produced at the end of regeneration and the total percentage replacement of the lost (autotomized) tails were significandy retarded in Px and NL (HP) animals, compared with the NL (unoperated and nonpainted) ones. Since pinealectomy as well as light deprivation to the pineal abolished the stimulatory influence of long‐length photoperiods, the pineal gland is discussed here as a major transmitter of photic stimulus in lacertilian tail regeneration. It is presumed that in the lizard, as in mammals and some birds, the pineal gland acts by way of the neuroendocrine complex and/or the hypothalamohypophyseal axis.
Seasonal Effects of Pinealectomy on the Ovary of the Catfish Heteropneustes fossilis (Bloch) Under Normal Photothermal Conditions
Authors: Joy K. P. , Agha A. K.
Published: February 2007

Pinealectomy of Heteropneustes fossilis held under normal photoperiod and ambient temperature produced season‐dependent effects on ovarian activity. When the fish were pinealectomized in the preparatory phase (early light‐responsive period) and maintained until the early prespawning phase, there was an accelerated growth of the ovary, as adjudged from increased gonado‐somatic index (GSI), ovarian histology, elevated ovarian total protein and ascorbic acid levels, and an increased level of serum alkali‐labile protein phosphorus (vitellogenin). Pinealectomy was ineffective in the prespawning and spawning (late light‐responsive phase) and postspawning (light refractory) phases. The results suggest that the pineal exerts an inhibitory effect on the hypothalamo‐hypophysial‐ovarian axis and synchronizes temporally ovarian activity in response to increasing photothermal conditions such that spawning takes place at a time most suitable for the survival of the young.
Pineal Gland Free Amino Acids and Indoles During Postnatal Development of the Rat: Correlations in Individual Glands
Authors: McNulty J. A. , McReynolds H. D. , Bowman D. C.
Published: February 2007

Free amino acids and indoles were measured by HPLC in single pineal glands of 5‐, 10‐and 20‐day‐old rats sacrificed during mid‐light and mid‐dark at each age. Melatonin was detectable in neonates (5‐day‐old), but day vs night differences in indole constituents did not occur until 10 days of age. Free amino acid steady state levels were high in neonates and there was a tendency for reversal of day vs night differences coinciding with the onset of circadian rhythmicity in indole biosynthesis. High correlations (r > 0.85) existed for taurine vs. glutamate in individual glands regardless of age and time of sacrifice. These findings suggest that taurine and glutamate are biochemically interrelated and that developmental changes in amino acid metabolic pools reflect functional innervation of the gland.
Melatonin Effects on the Cytoskeletal Organization of MDCK and Neuroblastoma N1E‐115 Cells
Authors: Benítez‐King Gloria , Huerto‐Delgadillo Lourdes , Antón‐Tay Fernando
Published: February 2007

Despite the fact that many physiological and pharmacological actions of melatonin (MEL) have been described, its mechanism of action at the subcellular level remains unclear. It has been suggested that MEL has effects on cellular processes that involve microfilaments and microtubules. In the present study MEL effects on the cytoskel‐eton were evaluated in MDCK and N1E‐115 cells in which the microfilaments have been shown to participate in cell morphology and dome formation (MDCK) and the microtubules in neurite outgrowths.

After one day of culture with 10‐11 ‐10‐7 M MEL MDCK cells showed an increase in the number of elongated cells. After four days with the hormone, an increase in the incidence of MDCK cells contacting neighboring cells through long cytoplasmic elongations was observed. Actin antibody stain showed the appearance of thicker fluorescent fibres beneath the cell membrane and over the nucleus in the MEL treated cells. An increase in dome formation in confluent cells was also observed. In N1E‐115 cells MEL (10‐3‐10‐5 M) induced an increase in cell with neurite processes. Neurite outgrowth is clearly seen at 24 h after plating. MEL‐treated cells grow in clusters with neurites forming intricate networks. Antitubulin antibody stain showed long fluorescent neurites in the N1E‐115 MEL‐treated cells. A decrease in N1E‐115 neurite formation was observed with either serotonin or 6‐hydroxymelatonin (6OH‐MEL). However, the number of MDCK cells with cytoplasmic elongations was decreased only after 6OH‐MEL. We conclude that MEL action at the cellular level involves a modification of the cytoskeletal organization.
Development of an Organ Culture Technique Capable of Monitoring Most Pineal Gland Indole Metabolites
Authors: Morton D. J.
Published: February 2007

An intact pineal gland organ culture technique was developed which utilised radiolabelled tryptophan as the indolic precursor and two‐dimensional thin‐layer chromatography to separate the various indole metabolites produced. The method was capable of reproducibly separating and quantitating all tryptophan metabolites except 5‐methoxytryptophan which co‐chromatographed with tryptophan in all the solvent systems evaluated. Noradrenergic stimulation of cultured pineals led to a predictable increase in N‐acetyl‐serotonin and melatonin production, suggesting that the method was useful for biochemical and pharmacological studies on the pineal gland. Similarly evaluation of the results revealed that a strong linearity existed between N‐acetylserotonin and melatonin production and between actual and theoretical methylation as previously reported, again verifying the usefulness of the method developed.
Effects of Melatonin Agonists and Antagonists on Reproduction and Body Weight in the Siberian Hamster
Authors: Duncan Marilyn J. , Fang Jun‐Ming , Dubocovich Margarita L.
Published: February 2007

This study examined whether melatonin‐induced inhibition of testicular weight and body weight in vivo could be antagonized by luzindole, a competitive melatonin receptor antagonist, or methysergide, a competitive serotonin receptor antagonist. Adult male Siberian hamsters were exposed to a long photoperiod (16L:8D) and given daily injections of drugs 3 h before lights off for 7 weeks. Hamsters treated with melatonin (0.375 mg/kg) exhibited testicular regression and loss of body weight. These effects were also marked in hamsters treated concommitantly with melatonin (0.375 mg/kg) and luzindole (10 mg/kg). In other studies, chronic injections of luzindole (30 mg/kg) to juvenile hamster failed to antagonize testicular regression induced by either melatonin injections or exposure to a short day photoperiod (12L: 12D). In contrast, concommitant injections of methysergide (6.25 mg/kg) and melatonin attenuated testicular regression and loss of body weight. When administered alone, neither luzindole nor methysergide affected testicular weight or body weight, whereas chronic injections of 5‐methyoxyluzindole (10 mg/kg) mimicked the inhibitory effects of melatonin. 5‐Methoxyluzindole inhibits 2‐[125I]‐iodomelatonin binding to median eminence/pars tuberalis membranes with an affinity similar to that of melatonin. Luzindole shows lower affinity for the inhibition of 2‐[125I]‐iodomelatonin binding than melatonin, which may explain why luzindole is not an effective melatonin receptor antagonist when administered in vivo. Methysergide, which has a very low affinity for inhibition of 2‐[125I]‐iodomelatonin binding, probably inhibits the effects of melatonin by blocking serotonergic neurotransmission.
Pinealocyte subsurface cisterns I: Cytologieal aspects including three‐dimensional structure
Authors: Lutter Ilse , Heinzeller Thomas , Aschauer Beate
Published: February 2007

Tutter I, Heinzeller T, Aschauer B. Pinealocyte subsurface cisterns I: Cytological aspects including three‐dimensional structure. J Pineal Res 199 1 : 10:7&83.

Subsurface cisterns (ssc) in the pineal gland of Meriones unguiculatus have been characterized with transmission electron microscopy, freeze‐fracture, morphometry, and three‐dimensional reconstruction. Subsurface cisterns (which are observed only in pinealocytes and never in gliocytes) are cisterns of the endoplasmic reticulum (ER) approaching the plasmalemma at a distance of 15–20 nm. Freeze‐fracture preparations show that except for some ribosomes at the cytoplasmic face, the cistern membranes as well as the related portions of the plasmalemma are free of special or specifically arranged particles or pores. All ssc have a lumen of 15–20 nm width and underlie 5.6% of the plasmalemma in a single layer; neither collapsed types nor stacks of ssc could be observed. As seen from reconstructions, large ssc are fenestrated and are situated preferentially in regions where the neighboring pinealocyte also bears large ssc. As a consequence, double‐sided ssc, which can be observed in sections of (mostly large) ssc, are not a random phenomenon. In regions of the large ssc, adhering junctions are also concentrated. Tubules of 20‐nm diameter link ssc with deeper parts of the ER, particularly with the perinuclear cistern and with the tubulo‐cisternal network at the trans‐side of the Golgi apparatus. Besides ssc proper, a lot of small endplates of ER‐tubules are seen close to the plasmalemma. It is suggested that ssc form by the widening and fusing of such ER‐tubules and decrease by retraction of ER‐tubules from the cell surface.
Attenuated nocturnal rise in pineal and serum melatonin in a genetically cardiomyopathic Syrian hamster with a deficient calcium pump
Authors: Reiter Russel J. , White Ted , Lerchl Alexander , Stokkan Karl‐Arne , Rodriguez Carmen
Published: February 2007

Abstract: Day and nighttime melatonin production in the pineal gland was compared in normal and cardiomyopathic (polydystrophic) adult male Syrian hamsters. These strains of hamsters were selected for comparison because the cardiomyopathetic hamster displays a deficient transmembrane Ca2+‐pump in a number of tissues, and intracellular Ca2+ concentrations ([Ca2+]i) play a central role in the nocturnal increase in pineal melatonin synthesis. Daytime levels of all constituents measured, i.e., pineal N‐acetyltransferase (NAT) activity, pineal and serum melatonin levels, and pineal 5‐hydroxytryptophan (5‐HTP), serotonin, and 5‐hydroxyindole acetic acid (5‐HIAA) contents, were comparable in control and dystrophic hamsters. In contrast, the nighttime rises in pineal NAT activity and pineal and serum melatonin levels were significantly attenuated in the dystrophic hamsters. By comparison, the pineal contents of 5‐HTP, serotonin, and 5‐HIAA were essentially the same in both groups of hamsters with both pineal serotonin and 5‐HIAA values exhibiting the usual nighttime drop. It is presumed that the alterations in nocturnal melatonin production in the pineal gland of the cardiomyopathic hamster may relate to a generalized deficiency in the Ca2+‐pump in pinealocyte plasma membranes, which leads to unusually high [Ca2+]i, causing a depression of NAT activity; this leads to the commensurate decline in pineal and serum melatonin levels. Harderian gland NAT activity and melatonin levels were essentially similar in the two groups of animals, although NAT activity was slightly depressed in the dystrophic hamsters killed during the day. The reduced amounts of intrascapular brown fat in the cardiomyopathic hamster is speculated to be a result of the diminished amount of melatonin produced in these animals.
Melatonin administration during pregnancy retards sexual maturation of female offspring in the rat
Authors: Colmenero M.D. , Diaz B. , Miguel J.L. , González M.L.I. , Esquifino A. , Marin B.
Published: February 2007

Abstract: The influence of pineal gland function and of melatonin during pregnancy upon sexual maturation of female offspring in rats was examined. The following groups of Wistar rats were studied: (A) control, (B) melatonin treated (250 μg/100 g.b.w. per day) throughout pregnancy, and (c) pinealectomized (pin‐x). Melatonin was injected subcutaneously 2 hr before lights off. All groups were housed in 12‐hr L:12‐hr D. The female offspring were observed until the onset of puberty, and blood samples were collected 5.5 hr after lights off under red light for melatonin and LH determinations by RIA. Ovary, pineal, and pituitary gland as well as body weights were recorded. The offspring of melatonin‐treated rats showed later vaginal opening than did those of the other two groups (P < 0.05 vs. control and P < 0.01 vs. pin‐x offspring), which was accompanied by a lower LH concentration, 0.42 + 0.05 ng LH/ml, showing statistically significant differences with the control levels [1.00 + 0.22 ng LH/ml (P < 0.05)] and with the pin‐x group [1.16 + 0.22 ng LH/ml (P < 0.05)]. The percentage of rats in proestrus was higher in the offspring of pin‐x rats (78.6%; P < 0.01) compared to control offspring (30%) and offspring of melatonin‐treated rats (11.8%). The concentrations of melatonin, 5.5 hr after darkness, were not significantly different among groups. No differences were observed in the body, ovarian, and pineal weights of the studied offspring. The pituitary weight was significantly lower (P < 0.05) in the offspring of pin‐x rats than in the other two groups. Our results seem to conform with the fact that exogenous melatonin crosses the placental barrier. In sum, the results show an inhibitory influence of melatonin during fetal life on the development of the neuroendocrine reproductive axis of the rat.
Pineal gland “magnetosensitivity” to static magnetic fields is a consequence of induced electric currents (eddy currents)
Authors: Lerchl Alexander , Nonaka Keico O. , Reiter Russel J.
Published: February 2007

Abstract: During the past decade, a number of reports indicated that the mammalian pineal gland is magnetosensitive in terms of spatial orientation. This indication is based on observations that artificial alterations of the direction of the earth's magnetic field (MF) markedly decreased the gland's capability to synthesize melatonin. These findings, however, seem paradoxical since animals as well as humans experience such alterations whenever they turn their heads. Therefore, the potential of the pineal for sensing magnetic fields was re‐investigated. During the dark phase, rats were exposed to repeatedly inverted MFs, generated by two identical pairs of Helmholtz coils; one pair connected to a power supply automatically, the other pair manually using an integrated potentiometer. Only the pineals of animals exposed to the automatically activated field responded with a reduced activity of the rate‐limiting enzyme serotonin‐N‐acetyltransferase, lower melatonin levels and increases in serotonin and 5‐hydroxyindole acetic acid. Hence, MF exposure itself did not affect the pineal. Rather, induced eddy currents in the animals, resulting from rapid On/Off transients of the artificially applied MF, are most likely the explanation.
Pattern of pineal melatonin concentrations during prolonged exposure to short photoperiods in photosensitive and photoinsensitive Djungarian hamsters
Authors: Niklowitz Petra , De Geyter Maria , Schlatt Stephan , Hoffmann Klaus , Nieschlag Eberhard
Published: February 2007

Abstract: In the Djungarian hamster (Phodopus sungorus) there is strong evidence that the nightly decompression or lengthening, respectively, of the pineal melatonin pattern is involved in conveying the inhibitory influence of short photoperiods. Some hamsters, however, are insensitive to photoinhibitory influences; other late‐responding hamsters show a delayed reaction of several months. The daily pattern of pineal melatonin proves that the mechanisms determining long‐ or short‐day patterns become effective in the morning and evening hours when melatonin concentrations of photoinhibited hamsters are clearly elevated, while those of long‐day hamsters are reduced to negligible low values. At two decisive time points in the morning and evening, male and female early‐responding photosensitive hamsters were killed after 5, 10, 15, and 20 weeks in short photoperiods, nonresponding hamsters after 10 and 20 weeks, and late‐responding after 20 weeks. In all early‐responding hamsters changes in gonadal stage, body weight, and pelage color corresponded to the decompression of the nightly melatonin pattern. During prolonged exposure to short photoperiods a decrease of mean melatonin concentrations in the morning and an increase of evening concentrations was observed in both sexes. The lengthening of nightly elevated melatonin concentrations was missing in photoinsensitive hamsters. In late‐responding hamsters this decompression seems to be delayed, as melatonin concentrations of female late responders indicate. In conclusion, the lengthening of the melatonin pattern seems to predict a photoperiodic reaction of the effector system. The lengthened pattern of photosensitive hamsters may not be unchangeable, as it may be subjected to modifications during prolonged exposure to short photoperiods.
Normalization of the light/dark rhythm of melatonin after prolonged subcutaneous administration of interleukin‐2 in advanced small cell lung cancer patients
Authors: Viviani S. , Bidoli P. , Spinazzé S. , Rovelli F. , Lissoni P.
Published: February 2007

Abstract: It has been demonstrated that antitumor immune response is an IL‐2‐dependent phenomenon. Moreover, experimental results suggest the existence of interactions between IL‐2 and the pineal gland, which also plays a role in the control of immunity and cancer growth.

Alterations of both IL‐2 and melatonin secretion have been reported in cancer patients. To further investigate pineal/IL‐2 relationships in humans with cancer, we evaluated the melatonin rhythm in seven advanced small cell lung cancer patients, before and at weekly intervals during immunotherapy with IL‐2, given subcutaneously at a daily dose of 3 × 106 IU/m2 twice daily for 5 days/week for 4 weeks. Before IL‐2, no patient showed a light/dark rhythm of melatonin. IL‐2 administration induced a normalization of the melatonin circadian rhythm, with the appearance of a night time peak in 4/7 patients. This effect, however, disappeared with IL‐2 interruption in 3/4 patients. This preliminary study, by showing that IL‐2 may restore a normal melatonin rhythm, suggests that the anomalous pineal function in cancer may depend at least in part on the altered endogenous IL‐2 production.
Identification of luteinizing hormone‐like proteins in the ovine pineal gland
Authors: Noteborn H.P.J.M. , De Honing J. , De Jong F.H. , Ebels I. , Salemink C.A.
Published: February 2007

Abstract: A chemical analysis was instigated to investigate the identity of the luteinizing hormone (LH)‐like immunoactivity present in ovine pineal protein homogenates. Isolation of pineal LH‐like material was accomplished using a 0.1 M ammonium sulphate (pH 4.0) extraction followed by anion‐exchange chromatography. The resulting 3.0 M ammonium sulphate precipitate containing 70% of the LH‐like immunoactivity was refractionated by cation‐exchange and Sephadex G‐100 chromatography. Analysis of the pattern of recovered LH‐like immunoactivity in the Sephadex G‐100 eluate indicated the presence of molecular weight (MW) < 60,000 besides MW 21,000 species of LH‐like proteins. Bioactivity was tested in the rat Leydig cell steroidogenesis assay. In terms of steroid production, the activity was associated with the MW 21,000 LH‐like proteins only. Further purification by CM‐Sephadex chromatography and gel permeation HPLC was conducted in order to determine whether the physicochemi‐cal properties of pineal LH‐like material represented endogenous LH, synthesized and released by the ovine pituitary. It is concluded by a variety of means, including polyacrylamide gel electrophoresis, and amino acid and carbohydrate analyses, that at least two molecular forms of immunoactive LH‐like proteins occur in ovine pineal tissue. The M W 21,000 forms showed much similarity with ovine adenohypophyseal LH or with a complex mixture of its subunits. These observations contribute to the understanding of endocrine‐endocrine transducing events that may occur in this organ.
The pineal gland of the trumpet‐tailed rat (Octodon degus)
Authors: Uría H. , Antolín I. , Tolivia D. , Rodríguez‐Colunga M.J. , Menéndez‐Peláez A.
Published: February 2007

Abstract: The structure and ultrastructure of the pineal gland of the degu or trumpet‐tailed rat (Octodon degus), a rodent inhabiting tropical‐equatorial areas, was examined under light and electron microscopy. On the basis of its form, size, and location, the pineal gland of the degu is classified as a proximal or “A” type. The connective tissue appeared poorly developed and the gland contained non‐fenestrated capillaries. A single population of typical pinealocytes was found. In addition, a small number of glial cells and cells with electron dense bodies appeared scattered throughout the gland. Cells with dense granules were found isolated or forming small groups always in close proximity to blood vessels. Numerous sympathetic nerve fibers with small dense‐core vesicles were found. Also, some myelinated nerve fibers were observed. The physiological significance of the presence of large electron‐dense granules in some pineal cells and their particular location around the blood vessels in discussed.
Melatonin binding sites in the Harderian gland of Syrian hamsters: Sexual differences and effect of castration
Authors: Menendez‐Pelaez Armando , Lopez‐Gonzalez Miguel A. , Guerrero Juan M.
Published: February 2007

Abstract: The presence of specific melatonin binding sites in the Harderian gland of Syrian hamsters was studied using [125I]melatonin. Saturation binding experiments conducted with [125I] melatonin at 37°C using Harderian glands of both male and female Syrian hamsters revealed a single nanomolar‐affinity site. The dissociation constants (Kd) were 6.47 and 6.94 nM for males and females, respectively. The concentration of the binding sites was 7.58 fmol/mg protein for males and 13.50 fmol/mg protein for females. Castration of male hamsters resulted in a significant increase in [125I] melatonin binding sites while chronic melatonin administration did not modify the binding properties. The results confirm the presence of melatonin binding sites in the Harderian glands of rodents. The gender‐associated differences found together with the effects of castration in male hamsters suggest an androgenic control in [125I] melatonin binding sites of the Syrian hamster Harderian gland.
The role of the pineal in the control of the daily patterns of neurohypophysial hormone secretion
Authors: Forsling Mary L. , Stoughton Roger P. , Zhou Van , Kelestimur Haluk , Demaine Cedric
Published: February 2007

Abstract: Plasma concentrations of neurohypophysial hormones show clear rhythms over 24 hr which can be suppressed by exposure to constant light, an observation consistent with pineal involvement. A study has therefore been performed on the changes in the hormone levels in the hypothalamus, posterior pituitary, and plasma over 24 hr in control, pinealectomised, and sham pinealectomised animals to determine if the pineal could play a role. Water intake, urine excretion, packed cell volume, plasma osmolality, and electrolytes were also monitored. Pinealectomy had little effect on fluid balance, but after 8 weeks for oxytocin and 2 weeks for vasopressin the morning values (0700–0800) for the circulating concentrations of the hormones were significantly higher in the pinealectomized group compared with the combined sham operated and unoperated groups (pineal intact). By contrast, the pituitary vasopressin was significantly lower in the pinealectomised group. The increase in plasma oxytocin and vasopressin seen over the hours of daylight and accompanying fall in plasma osmolality seen in the pineal intact group were absent in the pinealectomised group. Similarly, the evening fall in pituitary hormone concentrations and increase in hypothalamic hormone content were absent in the pinealectomised animals. After 10 days of exposure to constant light, the fall in plasma osmolality in the pineal‐intact animals over the day was no longer significant; instead a significant increase in plasma osmolality and sodium was seen in the pinealectomised group. Exposure to constant light, while altering the patterns of neurohypophysial activity in the pineal intact group, had little effect on the pinealectomised animals.
Tissue kallikrein in the rat pineal gland: An immunocytochemical study
Authors: Fujieda Hiroki , Sato Tetsuji , Wake Kenjiro , Takaoka Masanori , Morimoto Shiro
Published: February 2007

Abstract: Tissue kallikrein in the rat pineal gland was immunocytochemically investigated with the aid of specific antiserum against rat urinary kallikrein. We also compared the tissue kallikrein immunoreactivity of the pineal gland with that of the submandibular gland and kidney, which have been well established as tissue kallikrein‐synthesizing organs. The cytoplasm of pinealocytes from both the superficial and the deep portion of the gland exhibited specific immunolabeling for tissue kallikrein, but the immunoreaction was weaker than that observed in exocrine organs. Two types of tissue kallikrein‐immunoreactive pinealocytes were distinguished; the first predominant type displayed moderate immunostaining, whereas a small number of cells, the second type, were so intensely labeled that their cytoplasmic processes were clearly outlined. The results of the present study suggest the existence of different types of pinealocytes and a potential physiological role of tissue kallikrein in the rat pineal gland.
ELF magnetic fields, breast cancer, and melatonin: 60 Hz fields block melatonin's oncostatic action on ER+ breast cancer cell proliferation
Authors: Liburdy R.P. , Sloma T.R. , Sokolic R. , Yaswen P.
Published: February 2007

Abstract: In this study we investigated whether a 60 Hz magnetic field can act at the cellular level to influence the growth of human estrogen‐dependent breast cancer cells. Our experimental design assessed cell proliferation of a human breast cancer cell line, MCF‐7, in the absence or the presence of melatonin which inhibits growth at a physiological concentration of 10‐9 M. In three experiments, continuous exposure to average sinusoidal 60 Hz magnetic fields of 1.90 ± 0.01, 2.40 ± 0.70, and 2.53 ± 0.50 mG, or simultaneous exposure in matched incubators to average 60 Hz magnetic fields of 10.4 ± 2.12, 11.95 ± 2.73, and 11.95 ± 3.28 mG, respectively, had no effect on cell proliferation in the absence of melatonin. When MCF‐7 cells were cultured in the presence of 10‐9 M melatonin, an 18% inhibition of growth was observed for cells in a 2.40 ± 0.70 mG field. This effect was blocked by a 60 Hz magnetic field of 11.95 ± 2.75 mG. In a second experiment, a 27% inhibition of MCF‐7 cell growth was observed for cells in a 2.53 ± 0.50 mG magnetic field, and this was blocked by a 60 Hz magnetic field of 11.95 ± 3.28 mG. These results provide the first evidence that ELF frequency magnetic fields can act at the cellular level to enhance breast cancer cell proliferation by blocking melatonin's natural oncostatic action. In addition, there appears to be a dose threshold between 2 and 12 mG. The mechanism(s) of action is unknown and may involve modulation of signal transduction events associated with melatonin's regulation of cell growth.
Phototransduction‐related circadian changes in indoleamine metabolism in the chick pineal gland in vivo
Authors: Sun Jih‐Hsing , Reiter Russel J. , Hattorl Atsuhiko , Yaga Ken , Herbert Damon C. , Tsin Andrew T.C.
Published: February 2007

Abstract: The purpose of this study was to examine the day/night levels of pineal melatonin and its rate limiting enzyme N‐acetyltransferase (NAT) in relationship to the ratio of 11‐cis‐to all‐trans‐retinal. Three‐week‐old chicks were placed in 12:12 light: dark (LD 12:12) cycle for one week, pineals were collected during the light phase at 1500 (i.e., after 10 hr light), during the dark phase at 1900 (i.e., 2 hr after dark), at 2100 (i.e., 4 hr after dark), and at 2300 (i.e., 6 hr after dark) and after light extension to 1900. The results show that light‐sensitive 11‐cis‐retinal in the chick pineal has the same diurnal rhythm as NAT and melatonin; all constituents increased within 2 hr of darkness onset (at 1900) and reached their peak after 4 hr of dark. All values were lowest during the light phase at 1500. Low values for 11‐cis‐retinal, NAT, and melatonin were also seen in the group of chicks which experienced light extension to 1900. The data indicate that in vivo light plays a major role in triggering rhodopsin‐bound 11‐cis‐retinal production within 2–4 hr after darkness onset; this change likely serves as the signal for the subsequent formation of the hormonal product of the pineal gland, melatonin.
A non‐invasive simple method for measurement of urinary excretion of melatonin in undisturbed mice
Authors: Perissin Laura , Zorzet Sonia , Rapozzi Valentina , Giraldi Tullio
Published: February 2007

Abstract: Melatonin is a hormone involved in neuroendocrine responses; its plasma concentrations display a circadian pattern which is modified by stress. Studies for determining the effects of stressors on melatonin levels in laboratory animals present the difficulty that the procedures for blood sampling are by themselves potential stressors capable of influencing the levels of the hormone measured. A simple non‐stressful method for measuring urinary excretion of melatonin has been consequently developed. The method is applicable to single undisturbed mice kept in conventional cages, and consists of urine collection on chromatographic paper followed by extraction and melatonin assay by radioimmunoassay. The use of this method with BD2F1 mice indicates nocturnal excretion of melatonin significantly higher than during the day; nighttime melatonin levels were shown to be suppressed by constant illumination. A significant increase in nocturnal melatonin excretion was caused by the application of rotational stress applied as a mild experimental stressor.
Pineal modulation of the rat caudate‐putamen spontaneous neuronal activity: Roles of melatonin and vasotocin
Authors: Castillo‐Romero J.L. , Vives‐Montero F. , Reiter R.J. , Acuña‐Castroviejo D.
Published: February 2007

Abstract: The effects of microiontophoretic application of melatonin and melatonin plus vasotocin on spontaneously active neurons of caudate‐putamen in sham‐operated and pinealectomized rats were studied. Extracellular unit recordings showed that in sham‐pinealectomized rats, melatonin ejection primarily produced inhibition of the responsive neurons (74.1%), whereas only 24.9% of the neurons were excited. Iontophoretic ejection of vasotocin or melatonin + vasotocin produced, in both cases, an inhibition of 100% of the responsive neurons. In pinealectomized rats, iontophoretic melatonin ejection produced a similar percentage of inhibition (46.1%) and excitation (53.8%) of the responsive neurons. The simultaneous ejection of melatonin + vasotocin further increased the percentage of inhibition (88.8%) compared with the melatonin only treated group. Moreover, iontophoretic ejection of vasotocin inhibited 100% of the responsive neurons in pinealectomized rats. The actions of melatonin and vasotocin seem to be specific, because their effects are dependent on the amount of these compounds ejected, i.e., the intensity of the ejection current. These results indicate that the pineal compounds melatonin and vasotocin are neuromodulators of spontaneous neuronal activity of the rat caudate‐putamen.
Mode or inhibition or rat liver tryptophan 2,3‐dioxygenase by melatonin
Authors: Walsh H. A. , Daya S. , Whiteley C. G.
Published: February 2007

Walsh HA, Daya S, Whiteley CG. Mode of inhibition of rat liver tryptophan 2,3‐dioxygenase by melatonin. J. Pineal Res. 1994:16:188–192.

Liver tryptophan 2,3‐dioxygenase is a cytosolic enzyme that plays a crucial role in the regulation of circulating levels of tryptophan. Stimulation of the activity of this enzyme by heme enhances the catabolism of tryptophan, making less tryptophan available for uptake into the brain. Melatonin, the major hormone of the pineal gland, is shown to cause competitive inhibition of this enzyme (Ki = 2. 70 μM). This structural analog of the substrate L‐tryptophan is a negative homotropic cooperative modulator of the enzyme. The enzyme has a Km = 100 μM, and the substrate concentration required for optimum activity was found to be 2. 5 mM with substrate inhibition becoming a feature at higher levels of tryptophan.
Mode of action of inhibin‐like pineal antigonadotropin is different from melatonin during compensatory ovarian hypertrophy
Authors: Bhagat Lakshmi , Duraiswami S. , Muralidhar K.
Published: February 2007

Bhagat L, Duraiswami S, Muralidhar K. Mode of action of inhibin‐like pineal antigonadotropin is different from melatonin during compensatory ovarian hypertrophy. J. Pineal Res. 1994:16:193–197.

Both melatonin and pineal antigonadotropic peptides have the same end effect, i. e., prevention of the hypertrophic response when tested in the conventional compensatory ovarian hypertrophy (COH) model. The present work was undertaken to study the effect of melatonin and a melatonin‐ and steroid‐free inhibin‐like ovine pineal antigonadotropin (PI) on serum follicle stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL) following hemiovariec‐tomy in adult Holtzman rats and also to ascertain if any similarity exists in their mode of action during COH. While melatonin prevented the transient rise in FSH at 12 hr after unilateral ovariectomy (ULO), thus retaining the basal preoperative level, PI depressed basal levels of FSH too. In addition, melatonin suppressed PRL and LH levels at 12 hr and 120 hr after ULO, respectively. PI, on the other hand, had no effect on serum LH and PRL levels. In light of our earlier in vitro results, which showed a direct inhibitory effect of PI and not of melatonin on pituitary FSH synthesis and release, the present results indicate a dichotomy in the mode of action of PI and melatonin. PI acts directly at the level of the pituitary while melatonin may act at the level of the hypothalamus or higher brain centers to suppress the FSH surge and the ensuing compensatory response.
Changes in ovine pineal gland neuron‐specific enolase immunoreactivity following bilateral, but not unilateral, superior cervical ganglionectomy
Authors: Mockett Bruce G. , Lapwood Keith R.
Published: February 2007

Mockett BG, Lapwood KR. Changes in ovine pineal gland neuron‐specific enolase immunoreactivity following bilateral, but not unilateral, superior cervical ganglionectomy's. J. Pineal Res. 1994:16:202–209.

Pineal gland tissue from control and from unilaterally or bilaterally superior cervical ganglionectomized (SCGX) sheep was found to contain neuron‐specific enolase immunoreactive cells and nerve fibers. Morphological characteristics of pineal cells exhibiting immunoreactivity indicated that they were predominantly pinealocytes, while other cell types were nonimmunoreactive. Whereas bilateral SCGX resulted in a reduction in the size, and possibly number, of immunoreactive cells in the pineal, unilateral denervation did not result in any significant effects when compared with control pineals. Concomitant with the reduction in immunoreactivity in bilaterally denervated pineals was a significant increase in the volume of interstitial space, but not the number of nonimmunoreactive cells. These results suggest that sympathetic nerve fibers innervating the pineal of unilaterally sympathectomized sheep exhibited a degree of neural plasticity that resulted in denervated pinealocytes being reinnervated by remaining intact nerve terminals, thus preventing the occurrence of degenerative changes normally associated with complete loss of neural input through bilateral denervation. The fact that in unilaterally denervated sheep neither left nor right SCGX produced any discernible effects in either half of the pineal indicates that nerve fibers from each of the ganglia cross over to innervate the contra lateral as well as the ipsilateral pineal half. In the stalk of the pineal an extensive network of immunoreactive nerve fibers was found in both the caudal and habenular commissars, and occasionally these fibers were observed to enter the body of both intact and sympathetically denervated pineals. This latter result suggests that the sympathetic innervation enters the pineal over its surface and not via the stalk.
The pineal neurohormone melatonin prevents in vivo and in vitro apoptosis in thymocytes
Authors: Sainz Rosa M. , Mayo Juan C. , Uría Higinio , Kotler Mónica , Antolfn Isaac , Rodriguez Carmen , Menendez‐Pelaez† Armando
Published: February 2007

Abstract: Recently, melatonin was found to be the most potent physiological free radical scavenger known to date. In this work, we attempted to define the role this neurohormone plays in the regulation of apoptosis, since the effect of bcl‐2, the main gene implicated in its inhibition, acts via an antioxidant mechanism. We investigated the role of melatonin in cell death of thymus, a well known model for the study of apoptosis. Two sets of experiments were carried out: in vivo experiments, performed with Wistar rats, and in vitro experiments, performed with primary cultures of young Wistar rat thymocytes treated with glucocorticoids in order to induce apoptosis. Morphometrical studies in semithin sections of thymus and analysis of DNA fragmentation by gel electrophoresis show that physiological apoptosis occurring in thymus of 65 days old rats, is prevented by the daily administration of melatonin beginning when the rats were 25 days old. Also, we found that at a concentration of 10−7 M, melatonin decreases by 35% the percentage of apoptotic cells induced by glucocorticoids in cultured thymocytes of 25 day old rats. 10−9 M melatonin decreases cell death by 20%. Finally, melatonin at 10−11 Mdid not have any effect. Several hypothesis are discussed to explain this effect: direct interaction of melatonin with glucocorticoid receptors in the thymus; induction of interleukin‐4 release; direct genomic action modulating the expression of apoptosis‐inhibiting genes; an effect on nitric oxide synthase; and finally, the antioxidant action of melatonin. Since apoptosis is a possible mechanism involved in neuronal death shown in several neurodegenerative diseases such as Parkinson or Alzheimer's diseases, investigative efforts should be directed to the possible role of melatonin in inhibiting cell death in tissues other that the thymus. Melatonin might be a potent therapeutic agent in some of these conditions.
Melatonin reduces nitric oxide synthase activity in rat hypothalamus
Authors: Bettahi Ilham , Pozo David , Osuna Carmen , Reiter Russel J. , Acuña‐Castroviejo Dario , Guerrero Juan M.
Published: February 2007

Abstract: In this report, rat hypothalamic nitric oxide synthase (NOS) activity is shown to be partially inhibited by physiological concentrations of the pineal hormone melatonin. In vitro studies demonstrate that 1 nM melatonin, which approximates the physiological concentration of the hormone at night, significantly inhibited NOS activity. In vivo studies show that administering melatonin or collecting the hypothalamus from animals at night, when endogenous melatonin levels are elevated, results in a significant decrease of NOS activity. Results also show that calmodulin may be involved in this process since its presence in the incubation medium prevents the inhibitory effect of melatonin on NOS activity.