bluuebunny/crossref_metadata_2025 huggingface dataset:
Thrombus Aspiration with Export Catheter in ST Elevation Myocardial Infarction
Authors: MARGHERI MASSIMO , VITTORI GUIDO , CHECHI TANIA , FALCHETTI ELENA , COSGRAVE JOHN , SPAZIANI GAIA , RICCERI ILARIA , GIGLIOLI CHRISTINA , VALENTE SERAFINA , GENSINI GIAN FRANCO
Published: February 2007

Background: Many thrombectomy devices have failed to confirm initial promising results during primary angioplasty. This may be due to device complexity and operator experience. The objective of this study was to assess the safety and efficacy of the EXPORT catheter for thrombus aspiration in patients with ST elevation myocardial infarction (STEMI).

Methods: EXPORT catheter was used in patients with STEMI and angiographic evidence of thrombus in vessels with a reference diameter ≥1.5 mm. Direct stenting and glycoprotein IIb/IIIa inhibitors were liberally employed to optimize angiographic and clinical results. Epicardial and myocardial angiographic parameters, in‐hospital major adverse cardiac events (MACE, i.e., cardiac death, myocardial infarction, target vessel revascularization) were assessed.

Results: EXPORT catheter was used in 129 patients without any device‐related complications. Angiographic analysis following thrombus aspiration revealed a significant improvement in TIMI frame count (P = 0.0001), myocardial perfusion (P = 0.0001), TIMI thrombus grade (P = 0.0001), and TIMI flow (P = 0.0001). Stent implantation did not significantly improve myocardial perfusion, TIMI thrombus grade, or TIMI flow, but improved TIMI frame count, minimal lumen, and reference vessel diameter. When compared to a historical STEMI control group not undergoing thrombus aspiration, our EXPORT population showed significant improvements in reperfusion parameters. In‐hospital MACE were uncommon (4.5%) despite high‐risk patient characteristics.

Conclusions: Our study demonstrates that routine use of EXPORT catheter in patients with STEMI and coronary thrombosis is feasible, safe, and associated with significant improvements in flow‐related angiographic parameters. The relative simplicity of this approach makes it an attractive option in this challenging situation.
Efficiency, subsidies, and environmental adaptation of animal farming under CAP
Authors: Kleinhanß Werner , Murillo Carmen , San Juan Carlos , Sperlich Stefan
Published: February 2007

The purpose of this article is to model the interaction between the targets of the current Comman Agriculture Politic (CAP): environmental adaptation, subsidies, and efficiency of animal farming. To this end we first have to identify the production frontier and relative efficiency level for each animal‐oriented farm in the sample. The production frontier and efficiency index for each type of farm (assuming no specific production functions) are identified using Data Envelope Analysis (DEA) techniques. We then address the relationship between relative efficiency, farm size, and environmentally friendly behavior by carrying out a nonparametric regression of efficiency, on economic size, a proxy for the degree of environmental appropriateness, and regional dummies. Calculations of the efficiency of the farms including direct subsidies are compared with the counterfactual exercise in the case in which direct subsidies are not considered. Finally, we look for relations between subsidies and factors such as farm size, efficiency, and environmentally friendly behavior. One key result shows that, on average direct payments generally tend to increase efficiency. However, in most of the cases the mean efficiency decreases as the percentage of direct payments rises. Direct payments are found to be positively related to environmentally friendly production, at least in Germany. However, in general, the direct payment system is not sufficient to offset the fact that the less environmentally friendly farms as well as the larger farms are more efficient.
Cytochemical Analysis of Calcium Distribution in the Superficial Pineal Gland of the Mongolian Gerbil
Authors: Welsh Marcia G.
Published: February 2007

The potassium pyroantimonate‐osmium method was employed to determine the distribution of cations in the superficial pineal gland of the Mongolian gerbil. The reaction product in the glands was presumed to be calcium following the use of both the chelator EGTA and x‐ray microanalysis. A gradient of reaction product was found in the pineal with the highest concentrations occurring in and around the pineal concretions (PC). The periphery of mature PC demonstrated a heavy precipitate as did the surrounding pinealocytes. PC‐associated pinealoeytes contained reaction product in many organelles, including small vesicles that appeared to be opening in the direction of the concretions. The vacuoles of the pinealocytes contained various concentrations of precipitate. The results obtained in the present investigation have led to a hypothesis on the formation of pineal concretions: (1) a pinealocyte vacuole is formed, (2) calcium is transported to the vacuole, (3) the cation content of the vacuole increases, and (4) the cations precipitate into an immature concretion. Fibrillar material and an amorphous substance located within the pinealocyte vacuole appear to form cation containing vesicles that contribute to the periphery of the developing PC, resulting in the continued growth of the concretion.
Ultracytochemical Localization of Calcium in the Superficial Pineal Gland of the Mongolian Gerbil
Authors: Krstić Radivoj
Published: February 2007

In order to demonstrate fine localization of Ca2+ in the superficial pineal gland of Meriones unguiculatus, the pyroantimonate technique was employed. Control experiments were performed with EGTA and analysis of obtained reaction product using an energy‐dispersive x‐ray microanalysis.

Precipitates of calcium antimonate were formed almost exclusively in swollen clear pinealocytes, in and along their cell membranes, over their nuclei, in mitochondria, the Golgi apparatus, endoplasmic and integrade reticulums. acervuli, in vesicles surrounding synaptic bars, cytoplasmic matrix, and flocculent extracellular material. It has been concluded that the swollen pinealocytes represent a degenerative cell form probably occurring by impairment of plasmalemmal Ca2+‐ATPase's ability to eliminate Ca2+ ion from the cell, with consecutive increase of calcium in the cytoplasmic matrix, followed by increase of intramitochondrial Ca2+ concentration, gradual arrest of mitochondrial function, depolymerization of cytoskeletal microtubuli, loss of the cell form, and cell death. Decrease of function of pinealocyte plasmalemma seems to be related to aging.
The Effects of Spectral Power Distribution and Illuminance Levels on Key Parameters in the Male Golden Hamster and Rat With Preliminary Observations on the Effects of Pinealectomy
Authors: Hoffman Roger A. , Johnson Lucinda B. , Corth Richard
Published: February 2007

Three different light sources were used to determine the effects of spectral power distribution (SPD) and illuminance levels on growth and organ weights of male golden hamsters and rats. SPD had little effect on organ weights or measurements of either rats or hamsters. However, responses to illuminance levels were quite apparent, provided they were equalized for the scotopic eye sensitivity curve characteristic of nocturnal animals. Under seven illuminance levels from 0 to 3.9 scotopic fc, hamsters demonstrated graded responses in gonadal weights and presumed function from 0 to 0.02 scotopic fc. Above this level, photopic saturation was apparent. The neuroendocrine system of pinealectomized animals failed to show sensitivity to illuminance levels. The suggestion is made that the pineal gland acts to monitor illuminance levels (below about 0.02 scotopic fc) as well as photic duration. While the latter appears to be an “all or none” effect, the former appears to be graded.
Effects of Pineal Indoles and Arginine Vasotocin on Lipolysis and Lipogenesis in Isolated Adipocytes
Authors: Ng T. B. , Wong C. M.
Published: February 2007

The effects of arginine vasotocin and the pineal indoles melatonin, serotonin, Nacetylserotonin, hydroxytryptophol, methoxytryptophol, hydroxyindoleacetic acid, methoxyindoleacetic acid, and methoxytryptamine on lipolysis and lipogenesis in isolated adipocytes were studied. Basal lipolysis was inhibited by all the indoles tested at a dose of I μmole except hydroxytryptophol. Methoxytryptamine and serotonin inhibited hormone‐induced lipolysis in a dosedependent manner and exhibited the highest antilipolytic activity in isolated rat, rabbit, and hamster adipocytes. However, their antilipolytic activity could not be overcome by increasing the dose of the lipolytic hormone. Dibutyryl cyclic AMP‐induced lipolysis was also inhibited. All the pineal indoles tested were capable of suppressing basal and insulin‐stimulated lipogenesis in the dose range 0.33–3 nmole. At lower doses there was no effect. Arginine vasotocin at a dose of 25 nmole significantly augmented basal lipogenesis.
Effects of Timed Melatonin Infusion on Prolactin Secretion in Pineal Denervated Goat
Authors: Mori Yuji , Okamura Hiroaki
Published: February 2007

The effects of timed melatonin infusion on prolactin secretion were examined in the pineal denervated goat. Ovariectomized Shiba goats (n = 5) were subjected to bilateral superior cervical ganglionectomy (SCGX); this procedure resulted in complete abolition of endogenous melatonin release during the dark phase. SCGX goats failed to coordinate their prolactin secretion with the prevailing photoperiod. Melatonin was infused (20 μg/h, s. c.) daily into these goats either for 8 h (the long‐day‐type infusion) or for 16 h (the short‐day‐type infusion) to mimic the nocturnal profile of plasma melatonin under long days or short days, respectively. The long‐day‐type melatonin infusion for 9 days, in comparison with control saline infusion, accelerated prolactin secretion, inducing a nocturnal rise in plasma prolactin; this was comparable to that seen in the pineal intact goats under long photoperiods. On the other hand, the short‐day‐type melatonin infusion suppressed prolactin secretion throughout the day as the short‐day treatment did in intact goats. The prevailing photoperiod appeared to have no distinct effect on these prolactin responses to exogenous melatonin, which were indistinguishable under 16L8D and 8L16D conditions. The results indicate that the information about external light‐dark cycles is converted by the pineal gland into the endocrine signal as a daily pattern of melatonin secretion, which eventually regulates prolactin secretion from the pituitary gland of the goat.
Identification of a Cl−/Ca2+‐Dependent Glutamate (Quisqualate) Binding Site in Bovine Pineal Organ
Authors: Govitrapong Piyarat , Ebadi Manuchair , Murrin L. Charles
Published: February 2007

The presence of a high concentration of glutamic acid, a transmitter shown to have excitatory action in the pineal organ, prompted us to search for and to characterize glutamate receptor site in the bovine pineal organ. By using 10 nM‐100 μM of labeled and unlabeled L‐glutamate and by employing the LIGAND computer program, we found a glutamate binding site with a dissociation equilibrium constant (KD) of 0.534 μM and a receptor density (Bmax) of 4.84 pmol/mg protein. This pH‐ and temperature‐dependent binding site showed stereospecificity, was activated by Ca2+, and displayed affinity for both glutamate agonists and antagonists. The IC50 values for L‐glutamate, L‐asparate, L‐cysteate, L‐cysteine sulfinate, quisqualate, and (±) ibotenate were 0.5, 2, 12, 16, 25, and 30 μM, respectively, whereas those for D‐aspartate, L‐α‐aminoadipate, L‐homocysteate, and DL(±) 2‐amino‐4‐phosphonobutyrate were greater than 100 μM. Kainate, N‐methyl‐D‐aspartate, and L‐glutamic acid diethyl ester were inactive. Based on these results, the presence of a quisqualate‐type, Cl−/Ca2+‐dependent glutamate binding site in the pineal organ is suggested, and a possible neuroexcitatory role for glutamic acid, aspartic acid, and certain sulfur‐containing amino acids is also implied. The precise nature of this excitatory effect in modulating the function(s) of the pineal organ and the synthesis of its hormone(s) remains to be be elucidated.
Ontogeny of Circadian Rhythmicity for Melatonin, Serotonin, and N‐Acetylserotonin in Humans
Authors: Attanasio Andrea , Rager Klaus , Gupta Derek
Published: February 2007

The serum concentration of melatonin, serotonin, and N‐acetylserotonin were measured by RIA procedures in 28 infants aged 1 week to 9 months. Blood specimens were obtained at 1200 hr and 2400 hr. A day‐night difference in serum serotonin was present immediately after birth. A significant (P < 0.001) decrease in serum serotonin concentrations at 1200 hr and 2400 hr was observed from the first month of age to the third to ninth month of age. A significant (P < 0.05) difference in day‐night N‐acteylserotonin concentration is first seen at age 1–3 months. Serum melatonin concentrations, though detectable, did not show any day‐night difference at birth. Melatonin concentrations progressively increased up to the third month of age, and a significant (P < 0.01) day‐night difference appeared thereafter. The results indicate that in humans the circadian organizatijon for serotonin already exists at birth, and the circadian melatonin rhythm develops after birth.
Effects of Melatonin, Serotonin, and Naloxone on Aggression in Isolated Cichlid Fish (Aequidens pulcher)
Authors: Munro A. D.
Published: February 2007

Intracranial injections of 10 μg melatonin, with or without 4 μg naloxone, result in reduced aggressive responsiveness by the cichlid fish Aequidens pulcher to a mirror presented 20 min later. Naloxone, when administered on its own, had no behavioral effect. Intracranial injections of 25 μg serotonin‐creatinine sulphate complex (5HT‐CS) also reduced aggression. 5HT‐CS's action was abolished if the injection included 10 μg S‐adenosyl homocysteine (SAH), which inhibits the conversion of serotonin to melatonin. This suggests that the behavioral action of 5HT‐CS may be mediated by its conversion to melatonin. There is inconclusive evidence to suggest that 37.5 μg 5HT‐CS, administered in conjunction with 10 μg SAH, may reduce aggressiveness; injection of 50 μg 5HT‐CS, with or without 10 μg SAH, induced a pronounced escape behavior which precluded any measurement of aggressiveness in the fish.
A Light and Electron Microscopic Study of the Pineal Gland of the Viscacha (Lagostomus maximus maximus)
Authors: Domínguez Susana , Piezzi Ramón S. , Scardapane Luis , Guzmán Jorge A.
Published: February 2007

The pineal of viscacha (Lagostomus maximus maximus) is formed by two main cellular populations of pinealocytes and interstitial cells. A connective capsule surrounds the gland sending numerous septa containing blood vessels and nerves. In the specimens collected during summer the pinealocyte displays a defined contour and a clear cytoplasm with abundant ribosomes and numerous cisternae of endoplasmic reticulum. The pinealocytes observed during winter have cytological characteristics of active cells with dense and elongated mitocondria, dense bodies, and a developed Golgi complex. These seasonal glandular changes could be related to the environmental condition and mainly to the summer photoperiod. The presence of abundant nerve terminals in the perivascular spaces suggests a neural control on the blood vessels.
Pineal, Retinal, Serum Melatonin, and N‐Acetylserotonin Rhythms in Chicks on Reversing Light Regimen Eye Covering
Authors: Nir Isaac , Allen Andrée E. , Pang Shiu F.
Published: February 2007

After reversing a 12:12‐h light‐dark regimen of environmental lighting, pineal retinal melatonin levels of white leghorn chicks recorded at the first mid‐darkness were greatly enhanced reached maximum levels after three more days; those recorded during the light periods indicate gradual decline but were far from the nadir of the original light period, even at the end of the experiment.

The first mid‐darkness serum melatonin levels recorded after photoperiod reversal were not much different from their original mid‐light values. However, on continuing with the reversed regimen, the next mid‐darkness levels were sharply increased, maximum levels were reached after a further 2 days. Under the same experimental conditions light had much more drastic effects, 6 h on the reversed regimen were sufficient to bring down completely the high value of the original mid‐darkness period to the level of the starting mid‐light nadir.

Retinal N‐acetylserotonin (NAS) measured simultaneously had a pattern similar to that of melatonin, but the pineal NAS rhythm did invert completely, albeit gradually.

Eye covering did not prevent inversion of pineal serum melatonin rhythms, which were identical in eye‐covered sighted control chicks on the reversed regimen of light. However, retinal melatonin values of the light periods were significantly less depressed in eye‐covered than in sighted control chicks. Moreover, eye covering completely prevented the retinal NAS depression under light but did not affect pineal NAS. During darkness retinal pineal NAS elevation was sluggish in the eye‐covered chicks.
Positive Relationship Between the Nocturnal Concentrations of Melatonin and Prolactin, and a Stimulation of Prolactin After Melatonin Administration in Young Men
Authors: Webley G. E. , Böhle A. , Leidenberger F. A.
Published: February 2007

The relationship between the concentrations of melatonin and prolactin over the 24‐h cycle has been investigated in a group of young men at three times in the year. Melatonin and prolactin showed a significant positive correlation (P < 0.001) for all times during the 24‐h period but with a greater contribution from concentrations during the nocturnal period, when both hormones were elevated. The positive correlation for nocturnal concentrations was evident in February and March (P < 0.01) but was of greatest significance in June (P < 0.001). In blood samples taken at 15‐min intervals during the morning (0800–1200) and evening (2000–2400), melatonin and prolactin concentrations were not significantly correlated. Melatonin concentrations increased before prolactin during the evening and decreased before prolactin in the morning. Oral administration of 6 mg melatonin significantly stimulated prolactin release above concentrations measured after placebo administration, in both the morning (P < 0.05) and evening (P < 0.01) time periods; the prolactin response being greater in the evening. These results provide evidence for melatonin controlling the nocturnal increase of prolactin via its ability to stimulate prolactin release.
Constant Pineal Output and Increasing Body Mass Account for Declining Melatonin Levels During Human Growth and Sexual Maturation
Authors: Young Ian M. , Francis Peter L. , Leone Anna M. , Stovell Paul , Silman Robert E.
Published: February 2007

Twenty‐four‐h urine samples, divided into two fractions representing night‐ and daytime melatonin production, were collected from 115 healthy individuals between the ages of 3 and 80, of known height and weight, and assayed for 6‐hydroxy melatonin sulphate (SaMT), a major urinary metabolite of melatonin, by gas chromatography mass spectrometry. The population was divided for analytical purposes into children (boys aged 3–10.99, girls aged 3–9.59), adolescents (males aged 11–17.99, females aged 9.60–17.99), and adults (men and women over 18). The results showed approximately the same excretion over 24 h in all 3 groups but that the night/day ratio was considerably greater in children and adolescents compared to adults (P < 0.001). However, when the results were expressed as a function of body weight (BW), body surface area (BSA), or creatinine excretion (CE), nocturnal SaMT was higher in children than in adults (P < 0.001 for all 3 parameters) or adolescents (BW, P < 0.001; BSA, P < 0.002; CE, P < 0.001) and was higher in adolescents than in adults (BW and BSA, P < 0.001). Children also excreted more during the day than adults (BW, P < 0.01; CE, P < 0.001) or adolescents (BWαCE, P < 0.02). Our results show that pineal output barely changes during childhood and adolescence. However, there is an age related decrease in SaMT excretion/unit body mass which correlates with an age‐related increase in body mass. We therefore conclude that the decrease in circulating levels of melatonin during growth and sexual maturation is brought about by an increase in body mass.
Ultrastructure of the Pineal Gland in the Adult Dog
Authors: Calvo J. , Boya J. , Garcia‐Mauriño E.
Published: February 2007

The adult dog pineal gland was studied with the electron microscope. Pineal connective tissue spaces were poorly developed and showed capillaries with nonfenestrated endothelial cells. Two cell types, pinealocytes and astrocytes, could be identified in pineal parenchyma. Dog pinealocytes showed microtubules, centrioles, occasional cilia, and well‐developed Golgi complexes. These cells showed thin processes with bulbous endings packed with vesicles. Astrocytes were characterized by the presence of numerous filaments. Their processes finished forming a glial layer bordering connective tissue spaces. The presence of myelinated and unmyelinated nerve fibers was also described.
Hypothalamic and Neurohypophysial Vasopressin and Oxytocin in Melatonin‐Treated Pinealectomized Male Rats
Authors: Juszczak Marlena , Guzek Jan W.
Published: February 2007

The effect of melatonin on hypothalamic and neurohypophysial vasopressin and oxytocin was investigated in normal and pinealectomized rats. Pinealectomy was followed by a decrease of both vasopressin and oxytocin content in the hypothalamus and neurohypophysis. In unpinealectomized rats, melatonin decreased vasopressin and oxytocin storage in the hypothalamo‐neurohypophysial system. Following pineal removal, melatonin did not augment the pinealectomy‐induced decrease of vasopressin and oxytocin in the neurohypophysis; the hypothalamic storage of both neurohormones was even higher when compared with vehicle‐treated animals.
Age, Photoperiodic Responses, and Pineal Function in Meadow Voles, Microtus pennsylvanicus
Authors: Donham R. S. , Horton T. H. , Rollag M. D. , Stetson M. H.
Published: February 2007

We tested whether juvenile males of Microtus pennsylvanicus were more sensitive than adults to the suppressive effects of short photoperiods. Voles were transferred to short photoperiods (10L:14D) at 20 or 80 d of age, and 60 d later (i.e., at 80 or 140 d) the animals were killed at intervals throughout the day and night. Pineal glands were collected for measurement of melatonin, and the testes were weighed. There were no differences in paired testicular weights of 80 and 140 d old animals held on long days (median testicular weights: 1,953 and 1,843 mg). In contrast, median testicular weights of voles held on short days were 504 and 1,112 mg, respectively, at 80 and 140 d of age; the testicular weights of both groups were significantly different from their age‐matched controls (P .001, two‐sample t‐tests on log transformed data). The responses of the two age groups were compared by normalizing the individual values by the mean and variance of the respective long‐day controls. This comparison suggests that the responsiveness to photoperiod decreases as the animals age (t‐test, P= .01). Duration and amplitude of the nocturnal rise in pineal melatonin content were similar in differently aged animals. In two experiments, voles were injected daily with melatonin from 20 to 80 or 80 to 140 d of age. Melatonin‐injected animals had smaller testes than did saline‐injected controls (ANOVA: P= .01), and injections were more effective in the afternoon than in the morning (P= .01). Comparison of the effectiveness of short day and melatonin injections in juvenile and adult voles suggests that while short days inhibited testicular development of young animals more than it induced regression of adults, this decrease in responsiveness may involve factors other than alterations in the nocturnal pattern of melatonin production.
Melatonin Content of the Pineal Gland in Different Mouse Strains
Authors: Goto Maki , Oshima Itsuki , Tomita Takeshi , Ebihara Shizufumi
Published: February 2007

Pineal melatonin content at several times during the day and night was measured in 36 inbred strains of mice (Mus musculus) kept under LD 12:12 cycles. The results have indicated that only five inbred strains have pineal melatonin content, with higher levels during the night and lower levels during the day; the other 31 strains do not contain detectable melatonin in their pineal gland at any of times examined. The former group includes two commonly used strains (C3H/He and CBA/Ms) and three wild‐derived strains (Mol‐A, Mol‐Nis, MOM). C3H and CBA mice showed a similar pattern of pineal melatonin rhythm with a peak at 2 hours before lights on. The peak levels were about 150 pg/gland in both strains. The rhythmic patterns of melatonin content in Mol‐A, Mol‐Nis, and MOM were slightly different from those in CBA and C3H. In the wild‐derived strains, the peak of melatonin content did not occur at 2 hours before lights on but tended to occur at midnight. The peak levels were 67–91 pg/gland at the highest point in these strains.
Retention and Metabolic Fate of [3H]‐Melatonin in the Spotted Skunk
Authors: Berria Matthew , Mead Rodney A.
Published: February 2007

Two experiments were designed to determine which tissues accumulate [3H]‐melatonin and the metabolic fate of this hormone in the spotted skunk. Tritiated melatonin was injected into the jugular vein of 10 anesthetized skunks 1‐3 h before the onset of darkness and allowed to circulate for 22 min before the vasculature was flushed with saline to clear radioactivity from the blood. Selected tissues were removed from five skunks and oxidized in a Packard Biological Oxidizer which yielded 95 ± 5% recovery of radioactivity. Relatively high amounts of radioactivity were found in the pineal (367 ± 304 dpm/mg tissue), ovary (69 ± 38 dpm/mg), pituitary (89 ± 56 dpm/mg), liver (107 ± 29 dpm/mg), and kidney (63 ± 15 dpm/mg). Relatively small amounts of [3H] were found in different brain regions (approximately 6‐7 dpm/mg). The uterus, pancreas, and temporalis muscle also accumulated radioactivity (approximately 13 dpm/mg). The lung retained the least amount of radioactivity (4 ± 1.3 dpm/mg). In the second experiment, hypothalami, pituitaries, and ovaries were removed from the remaining five females. Radioactivity from these tissues was extracted and subjected to thin‐layer chromatography. Melatonin accounted for approximately 70% of the radioactivity recovered while 6‐hydroxymelatonin and unidentified more polar compounds made up the majority of the melatonin metabolites. These data indicate that tissues other than the hypothalamus are able to accumulate [3H]‐melatonin.
Photoperiod History, Melatonin, and Reproductive Responses of Male Syrian Hamsters
Authors: Karp Jonathan D. , Dixon Michael E. , Powers J. Bradley
Published: February 2007

The action of melatonin (MEL) in mediating photoperiodic history (PPH) effects among male Syrian hamsters was investigated. In Exp. 1, pineal intact males in LD 14: 10 received daily injections of MEL (15 μg) or ethanol: saline vehicle (SAL) 1 h before lights off for 8 wk to generate two groups experiencing identical photoperiods but distinctly different MEL histories. Following the cessation of injections, males were transferred to either LD 12: 12 or LD 8: 16 for 8 wk to evaluate whether their reproductive response to the new photoperiod would be more influenced by prior PPH or prior MEL history; MEL history was the significant variable. LD 12: 12 caused gradual recrudescence in hamsters that were gonadally regressed following MEL injections. In contrast, LD 12: 12 caused gonadal regression in hamsters that had large testes following SAL injections. Exp. 2 evaluated whether PPH influences might be mediated by aftereffects on the period (tau) of the circadian pacemaker regulating many behavioral and physiological rhythms. Pineal intact hamsters were exposed to long or short T cycles consisting of an 8 h photoperiod, repeated every 24.67 h (long T) or 23.33 h (short T) to mimic the aftereffects generated by short or long photo‐periods. After 5 wk in these T‐cycle conditions, all males were transferred to LD 12: 12 for 11 wk. The reproductive response to LD 12: 12 was modestly influenced by T‐cycle history, even though each T‐cycle generated different patterns of entrainment to LD 12: 12. These findings support the hypothesis that the response of the reproductive system of male hamsters to an intermediate‐duration photoperiod depends upon the duration of nocturnal melatonin secretion associated with hamsters' previous PPH.
Alteration of Plasma Cation Levels in Rats Kept in Constant Light
Authors: Morton D. J.
Published: February 2007

A variety of reports indicate that some kind of interaction may exist between the pineal gland and cations. Of particular interest are the reports that indicate comparatively high levels of copper, manganese, and zinc in the pineal gland and that the pineal gland exhibits a circadian rhythm in calcium, magnesium, potassium, and sodium. There are, unfortunately, no reports suggesting a functional role for these findings. This study investigated circadian rhythms in circulating plasma cations in rats under 12/12 h light‐dark cycle and in rats whose pineal function had been suppressed by exposure to constant light for 1 and 7 days. Neither of the treatments affected circulating potassium levels but had some significant effects on sodium concentration at a number of time points without affecting the total amount of sodium circulating in a 24 h period. Calcium, magnesium, and zinc plasma concentrations were little affected by 1 day of constant light, while 7 days of constant light caused a dramatic and highly significant increase in the circulating levels of the three cations. The plasma levels of copper, on the other hand, while also being unaffected by 1 day were significantly depressed by 7 days of constant light. It is apparent, therefore, that the pineal gland may be involved in regulation of circulating levels of the cations measured. The functional significance of these observations is not clear at this stage but warrants further investigation.
Reproductive Responses of Male Microtus montanus to Photoperiod, Melatonin, and 6‐MBOA
Authors: Gower Barbara A. , Berger Patricia J.
Published: February 2007

Juvenile male Microtus montanus were examined for the effects of photoperiod, melatonin, and the naturally occurring reproductive stimulant 6‐MBOA on growth and sexual maturation. 6‐MBOA, present in sprouting grass, is an important environmental cue used for the initiation of reproduction in natural populations of this species. Long photoperiod (16:8) was stimulatory to body, testes, and seminal vesicle growth, while short photoperiod (8:16) inhibited these parameters. The pineal hormone melatonin, administered via daily afternoon injections (5 μg), was also inhibitory to all of the above parameters as well as to serum testosterone. 6‐MBOA, administered via injection (0.0001–100 μg) or dietary means (0.1 or 1.0 μg/gm unsifted chow), appeared unable to augment the rate of maturation in long‐photoperiod‐stimulated animals. When short‐photoperiod animals were treated with high doses of the compound (100 μg injected or 1.0 μg/gm sifted chow), body and gonadal growth was inhibited to a greater extent than when animals were exposed to short photoperiod alone, and serum LH was reduced. Lower doses of the compound had no effect. Melatonin‐treated animals experienced less maturational inhibition when simultaneously given a low dose of 6‐MBOA‐coated chow (1.0 μg/gm unsifted chow). A higher dose of 6‐MBOA (1.0 μg/gm sifted chow) was ineffective in preventing the response to melatonin. These results indicate that 1) male M. montanus utilize photoperiod, rather than 6‐MBOA, as a primary environmental cue, 2) high doses of 6‐MBOA can be inhibitory under short photoperiod, 3) juvenile male voles are highly sensitive to the inhibitory effects of exogenously administered melatonin, and 4) 6‐MBOA can partially prevent the inhibitory effects of melatonin on growth and sexual maturation.
Photoreceptor cell specific proteins of snake pineal
Authors: Kalsow Carolyn M. , Greenhouse Shelley S. , Gern William , Adamus Grazyna , Margrave Paul A. , Lang Laura S. , Donoso Larry A.
Published: February 2007

Abstract: The pineal body of lower vertebrates is saccular and directly photoreceptive. The pineal gland of mammals is parenchymal and not directly photoreceptive. The parenchymal morphology of snake pineal raises questions of direct photoreceptivity of snake pineal and of correspondence of molecular homology with morphological homology. S‐antigen and rhodopsin are highly conserved photoreceptor cell specific proteins. We used site‐specific monoclonal antibodies (MAb) to study S‐antigen and rhodopsin of snake pineal. Immunohistochemical reactivity of snake retina and pineal was compared to that of trout, guinea pig, and rat. MAb's to S‐antigen reacted with each pineal and retina tested, but reactivity of individual MAb's with snake tissue was more similar to that with trout than with rat or guinea pig tissue. MAb's to rhodopsin did not react with snake pineal, although they did react with the photoreceptive trout pineal body. MAb's to rhodopsin reacted with retina of each species. These results suggest that although snake pineal is morphologically similar to mammalian pineal, and like mammalian pineal is probably not directly photoreceptive, it does have S‐antigen homology with lower vertebrates such as trout.
No difference in day‐night serum melatonin concentration after pineal grafting into the third cerebral ventricle of pinealectomized rats
Authors: Wu Wutian , Scott David E. , Reiter Russel J.
Published: February 2007

Abstract: Serum melatonin concentration and its day‐night difference in pinealectomized, stereotaxically grafted rats with pineal transplants was examined. The nighttime serum melatonin concentration increased significantly only in pinealectomized rats that received two pineal transplants. In neither pinealectomized rats receiving two pineal glands and one cotransplant of superior cervical sympathetic ganglion nor pinealectomized‐ganglionectomized rats receiving two pineal transplants was there a demonstrable increase in serum melatonin concentration. Although some pineal transplanted hosts demonstrated increases in serum melatonin concentration, there was no day‐night variation in serum melatonin concentration. This may be due to a number of mitigating factors. Pineal grafts may not receive the appropriate functional reinnervation from the host brain due to the location of the transplantation in the cerebral ventricle or due to lack of sufficient time for the growth of invading host neurites.
Regulation of melatonin production by catecholamines and adenosine in a photoreceptive pineal organ. An in vitro study in the pike and the trout
Authors: Falcón J. , Thibault C. , Martin C. , Brun‐Marmillon J. , Claustrat B. , Collin J.‐P.
Published: February 2007

Abstract: The pineal organ of fish contains photoreceptor cells with structural and functional analogies to retinal photoreceptors. In these cells, the light/dark (LD) cycle influences the production of melatonin by controlling the activity of one of its synthetizing enzymes, serotonin N‐acetyltransferase (NAT). The daily rhythm in NAT activity is generated endogenously in the pike but not in the trout pineal. We report here that in addition to the LD information, chemical factors are also involved in the control of melatonin production. Adenosine and two of its analogs stimulated or inhibited NAT activity and melatonin release in cultured pike and trout pineals, depending on the experimental conditions. It is believed that the nucleoside, produced locally, exerts a modulatory role on the neurohormonal output via still enigmatic mechanisms, involving a transmembranous carrier. Nocturnal melatonin production in cultured pike pineals was inhibited by α‐adrenergic agonists and stimulated by a β‐adrenergic agonist. No effect could be induced in trout pineals cultured under similar conditions. Because melatonin production by pineal photoreceptors is apparently regulated by both light and chemical inputs, we propose they might be multieffector cells.
The effect of pinealectomy and autonomic denervation on crypt cell proliferation in the rat small intestine
Authors: Callaghan B.D.
Published: February 2007

Abstract: Previously it has been found that pinealectomy in rats was associated with increased small bowel crypt cell proliferation. The hypothalamus is thought to play a role in the neural control of crypt cell proliferation and the pineal gland is known to be functionally connected with this component of the autonomic nervous system. Consequently, the effect on crypt cell mitotic rate of pinealectomy with autonomic ienervation of the rat small bowel (local sympathectomy and truncal vagotomy) was observed to determine the possible importance of the autonomic nervous system in the mediation of the effects of pinealectomy on the crypts.

It was found that interruption of either the vagal or sympathetic nerve supply to the small intestine both significantly decreased the usual hyperproliferative effect on the crypt cells observed after pinealectomy. It is suggested that the overall effect of the pineal gland is to suppress the crypt cell proliferation rate and that this effect is mediated, at least to some extent, by (1) the direct connections between the pineal gland and the hypothalamus, (2) the connections between the hypothalamus and the vagal and sympathetic innervation of the gut, and (3) the influence of the autonomic innervation on the activity of the enteric plexuses in relationship to the crypts. The pineal may have a role in modulating the local control mechanism of crypt cell proliferation. Its exact role in the control of crypt cell proliferation has not yet been defined.
Adenosine effects on the rat pineal gland in vitro: Cyclic adenosine monophosphate levels, N‐acetyltransferase, and thyroxine type II 5′‐deiodinase activities and melatonin production
Authors: Nonaka K.O. , Reiter R.J. , Withyachumnarnkul B. , Stokkan K‐A. , Lerchl A.
Published: February 2007

Abstract: The presence of adenosine and its receptors in the pineal gland suggests that they could have a regulatory influence on pineal physiology. Rat pineal glands cultured in the presence of the adenosine analog 5′‐N‐ethylcarboxamido adenosine (NECA) promoted a significant increase in pineal adenosine 3′5′‐monophosphate (cAMP) content, similar to that caused by the ß‐adrenergic receptor agonist isoproterenol (ISO). A potentiation of the cAMP response occurred when the glands were simultaneously stimulated with both NECA and ISO. Whereas high cAMP levels induced by ISO were associated with an increased N‐acetyltransferase (NAT) activity and rise in the melatonin production and release, the NECA‐induced rise in cAMP concentration failed to promote an increase in the activity of either NAT or another pineal enzyme thyroxine 5′‐deiodinase type II; likewise, pineal melatonin levels did not rise.
Urinary 6‐sulphatoxymelatonin, an index of pineal function in the rat
Authors: Brown Gregory M. , Bar‐Or Amit , Grossi Doreen , Kashur Suzanne , Johannson Erika , Yie Shang Mian
Published: February 2007

Abstract: The objective of this study was to apply the radioimmunoassay for 6‐sulphatoxymelatonin (aMT6s) to rat urine, and use it to study the source of aMT6s. The radioimmunoassay was found to have acceptable within‐ and between‐assay variation, excellent specificity, and good parallelism between the standard and unknown. Because urine is highly contaminated we assessed whether preliminary purification was required and established that it was unnecessary. Using this assay a 24‐hr rhythm in 6‐sulphatoxymelatonin output was seen in pools of urine harvested at 3‐hr intervals from Wistar rats on LD 12:12. The nocturnal rise in aMT6s was abolished by constant light. In contrast pinealectomy lowered aMT6s output significantly throughout both dark and light. This study confirms previous studies indicating that the pineal is the major source of 6‐sulphatoxymelatonin. It is concluded that urinary 6‐sulphatoxymelatonin as measured by radioimmunoassay is a valid measure of pineal gland activity in the rat.
Melatonin secretion during adrenarche in normal human puberty and in pubertal disorders
Authors: Cavallo Anita
Published: February 2007

Abstract: The relation between human melatonin secretion and adrenarche was investigated in 113 subjects ages 5.5–17 years. Melatonin nocturnal profile was determined obtaining hourly blood samples from 2000 to 0800 and DHEA‐S was measured in pooled plasma of these samples. In 62 normal subjects, melatonin peak by stages of adrenarche was 152.5 ± 65.4, 125.9 ± 59.4, and 115.2 ± 40.7 pg/ml for stages 1, 2, and 3–5, respectively, and the linear trend components were significant; no significant relation remained after partialling the variance associated with age and pubertal stages. In 41 subjects with disorders of pubertal onset, mean melatonin peak by stages of adrenarche was 149.0 ± 54.4, 194.0 ± 34.2, and 129.8 ± 52.2 pg/ml for stages 1, 2, and 3–5, respectively, and the linear trend components were not significant. In seven prepubertal girls with precocious adrenarche, melatonin peak was not significantly different from values in seven normal prepubertal, preadrenarchal girls. The relation between time of melatonin peak and adrenarche was not significant in any of the diagnostic groups. The linear correlation between melatonin peak and DHEA‐S was not significant in either adrenarche stage 1 (r = ‐0.19, n = 41) or stages 3–5 (r = ‐0.13, n = 23). The results do not support a role for adrenarche in the pineal‐puberty relation in humans.
Effect of the pineal gland on circadian rhythmicity of colony forming units for granulocytes and macrophages (CFU‐GM) from rat bone marrow cell cultures
Authors: Haldar Chandana , HäuBler Dietmar , Gupta Derek
Published: February 2007

Abstract: The present study provides evidence that the pineal gland has a physiological role in the proliferation of colony forming units for granulocytes and macrophages (CFU‐GM). A biphasic circadian rhythm of CFU‐GM proliferation in rat bone marrow cell cultures (BMC) from intact animals peaking at 0600 and 1800 was observed. Pinealectomy (Px) at 1600 obliterated the circadian rhythm patterns of CFU‐GM. Afternoon injections of melatonin (1630, 20 (μg/per day for 10 days) to Px animals restored the rhythmicity. When pinealectomy was done at 0800, the morning peak remained unaltered and the colony number at 1800 was higher than that found in the afternoon Px animals. In conclusion, the pineal gland or its main hormone melatonin seems to have a regulatory role in the proliferation of CFU‐GM in rat BMC. Further, the expression of the activity of CFU‐GM in rat BMC depends on the time when pinealectomy is done or melatonin is substituted.
Melatonin inhibits mammary gland development in female mice
Authors: Mediavilla M.D. , San Martín M. , Sánchez‐Barceló E.J.
Published: February 2007

Abstract: The objective of this study was to determine whether melatonin (aMT) influences the postnatal development of the mammary gland parenchyma in female mice from the time of weaning to adulthood. Twenty‐one‐day‐old female BALBc mice were treated with daily subcutaneous injections of aMT (200 (μg) or diluent, 3 hr before the onset of darkness (photoperiod LD 12:12). At 3, 5, 7, 9, 11, and 13 weeks of age, batches of 20 animals (ten controls and ten aMT‐treated) were sacrificed and the second pair of mammary glands were dissected to evaluate their degree of development. Melatonin decreased body weight gain from 2 weeks before until 2 weeks after the onset of puberty. Treatment with aMT also resulted in a lower DNA content and smaller area of the mammary gland from the time of puberty until the end of the study. In aMT‐treated mice the phase of highly positive allometric growth began 2 weeks later, but ended at the same time as in controls (11th week of life). Finally, aMT decreased the development of terminal, lateral, and alveolar buds while it increased the number of terminal ducts per gland. We conclude that pharmacological doses of aMT (1) reduce body weight gain at the peripuberal age; (2) partially inhibit postnatal mammary gland development by reducing the number of epithelial structures representing sites of growth and increasing that of structures representing the final state of ductal growth in virgin animals; (3) delay the onset of and shorten the phase of rapid mammary growth occurring in early postpuberal age.
Seasonal variations in pineal 5‐methoxytryptophol (5‐ML) concentrations and in the daily pattern of pineal 5‐ML and melatonin in the desert rodent Jaculus orientalis: Effect of prolonged illumination during the night
Authors: Lakhdar‐Ghazal N. , Vivien‐Roels B. , Pevet P.
Published: February 2007

Abstract: Seasonal variations in daytime pineal 5‐methoxytryptophol (5‐ML) and in the daily pattern of both pineal 5‐ML and melatonin concentrations were measured by radioimmunoassay in male and female jerboas, Jaculus orientalis. Pineal 5‐ML content was found to be low in winter and spring and showed a short but marked increase in summer. A clear daily rhythm was present in pineal 5‐ML in September, with high concentrations during daytime and low concentrations during nighttime. In May there was a considerable drop in the daytime values and a marked decrease in the amplitude of the rhythm, while in December the daily rhythm completely disappeared. On the contrary, a clear daily rhythm was observed for pineal melatonin in September, December, and May with high values during nighttime and low values during daytime; no differences in the amplitude of the rhythm could be observed. Illumination during early night prevented both the nocturnal decrease of 5‐ML and the increase of melatonin in September; in May illumination had no clear effect on 5‐ML, while it prevented the normal increase of melatonin. These results suggest a possible desynchronization between the regulation of 5‐ML and melatonin synthesis and release, and stress the complexity of the mechanisms involved in the environmental synchronization of seasonal functions.
Melatonin concentration in the umbilical artery and vein in human preterm and term neonates and neonates with acute fetal distress
Authors: Muñoz‐Hoyos Antonio , Rodriguez‐Cabezas Trinidad , Molina‐Carballo Antonio , Martinez‐Sempere Juan Jose , Ruiz‐Cosano Carlos , Acuña‐Castroviejo Darío
Published: February 2007

Abstract: In order to assess the existence of a rhythmic secretion of melatonin (aMT) in newborns and whether this rhythm is affected by neonatal stress, we studied 112 newborns classified in three groups: normal babies delivered at term, preterm infants born before the 38th week, and babies with fetal distress. Melatonin was measured by RIA in the umbilical artery and vein at the time of birth. Melatonin levels in umbilical arterial and venous blood showed a diurnal rhythm in all groups. Melatonin levels in umbilical cord artery and vein were closely related. Nocturnal melatonin levels were increased in newborns with acute fetal distress in comparison with normal term and preterm neonates. These results suggest that (1) a rhythm of aMT secretion exists in newborns, although it cannot be determined whether this rhythm is of maternal or fetal origin and (2) neonatal stress (acute fetal distress) increases aMT production during the night in comparison with normal term and preterm neonates.