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R Pineda

Publications and source records attributed to R Pineda.

At least 19 recordsLinked to original sources
PubMed2006

Neuromedin s as novel putative regulator of luteinizing hormone secretion.

Neuromedin S (NMS), a 36 amino acid peptide structurally related to neuromedin U, was recently identified in rat brain as ligand for the G protein-coupled receptor FM4/TGR-1, also termed neuromedin U receptor type-2 (NMU2R). Central expression of NMS appears restricted to the suprachiasmatic nucleus, and NMS has been involved in the regulation of dark-light rhythms and suppression of food intake. Reproduction is known to be tightly regulated by metabolic and photoperiodic cues. Yet the potential contribution of NMS to the control of reproductive axis remains unexplored. We report herein analyses of hypothalamic expression of NMS and NMU2R genes, as well as LH responses to NMS, in different developmental and functional states of the female rat. Expression of NMS and NMU2R genes was detected at the hypothalamus along postnatal development, with significant fluctuations of their relative levels (maximum at prepubertal stage and adulthood). In adult females, hypothalamic expression of NMS (which was confined to suprachiasmatic nucleus) and NMU2R significantly varied during the estrous cycle (maximum at proestrus) and was lowered after ovariectomy and enhanced after progesterone supplementation. Central administration of NMS evoked modest LH secretory responses in pubertal and cyclic females at diestrus, whereas exaggerated LH secretory bursts were elicited by NMS at estrus and after short-term fasting. Conversely, NMS significantly decreased elevated LH concentrations of ovariectomized rats. In summary, we provide herein novel evidence for the ability of NMS to modulate LH secretion in the female rat. Moreover, hypothalamic expression of NMS and NMU2R genes appeared dependent on the functional state of the female reproductive axis. Our data are the first to disclose the potential implication of NMS in the regulation of gonadotropic axis, a function that may contribute to the integration of circadian rhythms, energy balance, and reproduction.

Aging↗
PubMed2006

Effects of galanin-like peptide on luteinizing hormone secretion in the rat: sexually dimorphic responses and enhanced sensitivity at male puberty.

Reproductive function is exquisitely sensitive to adequacy of nutrition and fuel reserves, through mechanisms that are yet to be completely elucidated. Galanin-like peptide (GALP) has recently emerged as another neuropeptide link that couples reproduction and metabolism. However, although the effects of GALP on luteinizing hormone (LH) secretion have been studied, no systematic investigation on how these responses might differ along sexual maturation and between sexes has been reported. Moreover, the influence of metabolic status and potential interplay with other relevant neurotransmitters controlling LH secretion remain ill defined. These facets of GALP physiology were addressed herein. Intracerebral injection of GALP to male rats induced a dose-dependent increase in serum LH levels, the magnitude of which was significantly greater in pubertal than in adult males. In contrast, negligible LH responses to GALP were detected in pubertal or adult female rats at diestrus. Neonatal androgen treatment to females failed to "masculinize" the pattern of LH response to GALP. In addition, metabolic stress by short-term fasting did not prevent but rather amplified LH responses to GALP in pubertal males, whereas these responses were abrogated by pharmacological inhibition of nitric oxide synthesis. We conclude that the ability of GALP to evoke LH secretion is sexually differentiated, with maximal responses at male puberty, a phenomenon which was not reverted by manipulation of sex steroid milieu during the critical neonatal period and was sensitive to metabolic stress. This state of LH hyperresponsiveness may prove relevant for the mechanisms relaying metabolic status to the reproductive axis in male puberty.

Androgens↗
PubMed2006

Stimulatory effect of PYY-(3-36) on gonadotropin secretion is potentiated in fasted rats.

Development and normal function of the reproductive axis requires a precise degree of body energy stores. Polypeptide YY-(3-36) [PYY-(3-36)] is a gastrointestinal secreted molecule recently shown to be involved in the control of food intake with agonistic activity on neuropeptide Y (NPY) receptor subtypes Y2 and Y5. Notably, PYY-(3-36) has been recently demonstrated as putative regulator of gonadotropin secretion in the rat. However, the "reproductive" facet of this factor remains to be fully elucidated. In this context, we report herein our analyses of the influence of the nutritional status on the effects of PYY-(3-36) upon GnRH and gonadotropin secretion. The major findings of our study are 1) the stimulatory effect of central administration of PYY-(3-36) on LH secretion was significantly enhanced after fasting and blocked by a GnRH antagonist; 2) besides central effects, PYY-(3-36) elicited LH and FSH secretion directly at the pituitary level, a response that is also augmented by fasting; 3) PYY-(3-36) inhibited GnRH secretion by hypothalamic fragments from male rats fed ad libitum, whereas a significant stimulatory effect was observed after fasting; and 4) the increase in the gonadotropin responsiveness to PYY-(3-36) in fasting was not associated with changes in the expression of Y2 and Y5 receptor genes at hypothalamus and/or pituitary. In conclusion, our study extends our previous observations suggesting a relevant, mostly stimulatory, role of PYY-(3-36) in the control of gonadotropin secretion. Strikingly, such an effect was significantly enhanced by fasting. Considering the proposed decrease in PYY-(3-36) levels after fasting, the possibility that reduced PYY-(3-36) secretion might contribute to defective function of the gonadotropic axis after food deprivation merits further investigation.

Animals↗
PubMed2005

Pattern of orexin expression and direct biological actions of orexin-a in rat testis.

Orexins, hypothalamic neuropeptides initially involved in the control of food intake and sleep-wake cycle, have recently emerged as pleiotropic regulators of different biological systems, including the reproductive axis. Besides central actions, peripheral expression and functions of orexins have been reported, and prepro-orexin and orexin type-1 receptor mRNAs have been detected in the testis. However, the pattern of expression and biological actions of orexin in the male gonad remain mostly unexplored. In this study, we report analyses on testicular prepro-orexin mRNA expression and orexin-A immunoreactivity in different experimental settings, and on direct effects of orexin-A on seminiferous tubule functions. Expression of prepro-orexin mRNA was demonstrated in the rat testis at different stages of postnatal development, with negligible levels at early juvenile period and maximum values in adulthood. Likewise, orexin-A immunoreactivity was demonstrated along postnatal maturation, with strong peptide signal in Leydig cells and spermatocytes at specific stages of meiosis. Testicular expression of prepro-orexin mRNA appeared hormonally regulated; its levels decreased after hypophysectomy and increased after gonadotropin replacement and ghrelin stimulation. Finally, orexin-A suppressed the expression of key Sertoli cell genes, such as Müllerian-inhibiting substance and stem cell factor, and inhibited DNA synthesis in specific stages of the seminiferous epithelium. In conclusion, we provide evidence for the regulated expression of orexin in the rat testis and its potential involvement in the control of seminiferous tubule functions. Together with our recent results on the expression of orexin type-1 receptor in the rat testis, our data further document a novel testicular site of action of orexins in the control of male reproductive axis.

Aging↗
PubMed2004

Orexin 1 receptor messenger ribonucleic acid expression and stimulation of testosterone secretion by orexin-A in rat testis.

Orexins are hypothalamic neuropeptides primarily involved in the regulation of food intake and arousal states. In addition, a role for orexins as central neuroendocrine modulators of reproductive function has recently emerged. Prepro-orexin and orexin type-1 receptor mRNAs have been detected in the rat testis. This raises the possibility of additional peripheral actions of orexins in the control of reproductive axis, which remains so far unexplored. To analyze the biological effects and mechanisms of action of orexins in the male gonad, we evaluated testicular expression of orexin receptor 1 (OX(1)R) and orexin receptor 2 (OX(2)R) mRNAs in different experimental settings and the effect of orexin-A on testicular testosterone (T) secretion. Persistent expression of OX(1)R mRNA was demonstrated in the rat testis throughout postnatal development. In contrast, OX(2)R transcript was not detected at any developmental stage. Expression of OX(1)R mRNA persisted after selective elimination of mature Leydig cells and was detected in isolated seminiferous tubules at defined stages of the seminiferous epithelial cycle. In addition, testicular OX(1)R mRNA expression appeared to be under hormonal regulation; it was reduced by long-term hypophysectomy and partially restored by FSH replacement, whereas down-regulation was observed after exposure to increasing doses of the ligand in vitro. Moreover, OX(1)R mRNA expression was sensitive to neonatal imprinting by estrogen. Finally, orexin-A, in a dose-dependent manner, significantly increased basal, but not human choriogonadotropin-stimulated, T secretion in vitro. A similar stimulatory effect was observed in vivo after intratesticular administration of orexin-A. In conclusion, our present results provide the first evidence for the regulated expression of OX(1)R mRNA and functional role of orexin-A in the rat testis. Overall, our data are suggestive of a novel site of action of orexins in the control of male reproductive axis.

Aging↗
PubMed2004

Microbial characterization of organic carrier colonization during a model biofiltration experiment.

AIMS: Dynamic microbial characterization of the colonization of organic carrier during a model biofiltration experiment using methanol as air pollutant. METHODS AND RESULTS: A model biofilter was used in order to characterize the micro-organisms involved in the colonization of a model organic carrier. The model system consisted of closed vial as biofilter, peanut shells as lignocellulosic carrier and methanol as air pollutant. The micro-organisms involved in biofiltration were identified and characterized for their lignocellulolytic and methylotrophic activities. Fungi presented a higher lignocellulolytic activity than bacteria. A steady-state was reached after 15 to 20 days. CONCLUSIONS: The consortium naturally associated to peanut shells is limited to few aerobic bacteria and lignocellulolytic fungi. This consortium was able to degrade methanol without external nutrient supply. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first paper that focuses on carrier degradation processes and the micro-organisms involved during the start-up period of a biofiltration process.

Air Pollutants↗
PubMed2001

Diffuse lamellar keratitis: incidence, associations, outcomes, and a new classification system.

PURPOSE: To evaluate the incidence, associations, and visual outcomes in patients with diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK). SETTING: University-based refractive surgery center, Boston, Massachusetts, USA. METHODS: This retrospective review comprised 2711 eyes that had LASIK between September 1996 and September 1999. All eyes that developed DLK after LASIK were included. They were divided into type I DLK (center sparing) or type II DLK (center involved) and then subdivided into A (sporadic-DLK not diagnosed in other patients treated on the same day) or B (cluster-other patients identified with DLK). Type IA corresponded to center sparing, sporadic; type IB, center sparing, cluster; type IIA, center involved, sporadic; and type IIB, center involved, cluster. The main outcome measures were incidence of DLK after LASIK, time to diagnosis, time to resolution, and changes in best spectacle-corrected visual acuity (BSCVA). Unpaired t tests were used for statistical analyses. RESULTS: Thirty-six eyes (1.3%) developed DLK. Type I occurred in 58.3% of cases (type IA, n = 18; type IB, n = 3) and type II, in 41.7% (type IIA, n = 10; type IIB, n = 5). The mean time to diagnosis was not statistically significantly different between type I (1.8 days) and type II (1.1 days). Fourteen eyes (38.9%) developed DLK after an epithelial defect, representing an odds ratio of 13 times. The association with an epithelial defect was statistically significantly greater with type I (11/21 eyes, 52.4%) than with type II (3/15 eyes, 20.0%; P =.05). The mean time to resolution was 3.5 days in type I (type IA = 3.6 days; type IB = 2.7 days). This was significantly shorter than in type II, which had a mean time to resolution of 12.1 days (type IIA = 9.3 days; type IIB = 10.2 days) (P =.001). Loss of 2 or more lines of BSCVA occurred in 2 of 5 patients with type IIB and in no patients with types IA, IB, or IIA. CONCLUSIONS: Epithelial defects after LASIK increased the risk of DLK occurrence, especially type I. Type II DLK was associated with a prolonged time to resolution and carried a significantly higher risk of BSCVA loss than type I.

Administration, Topical↗
PubMed2000

Anticholinergic bronchodilators in combination.

Chronic obstructive pulmonary disease (COPD), which affects approximately 14 million Americans, is the fourth leading cause of death in the United States and is responsible for an estimated US$6.5 billion in direct and indirect costs per year [1,2]. Its usual course is a slow deterioration of lung function and progressive breathlessness with activities. The age-adjusted death rate for COPD rose 71% from 1967 to 1987, and the 10 year mortality rate is about 50%. Bronchodilators form one of the mainstays of therapy in COPD patients. The judicious use of these agents increases airflow and reduces dyspnea in patients with COPD. Patients often experience a reduction in symptoms and improvement in their quality of life. There are several classes of bronchodilators available for the treatment of COPD, each with specific clinical benefits: anticholinergics, short-acting beta 2 agonists, combination anticholinergic and short-acting beta 2 agonist, long-acting beta 2 agonists and methylxanthines. This chapter reviews the use of an anticholinergic (ipratropium bromide) concomitantly with other bronchodilators, focusing on patients with COPD.

Bronchodilator Agents↗
PubMed2000

[Fatty acids composition and proximate of 7 fish species of Isla de Pascua].

During the last years the study of fatty acids belonging to omega 3 family in marine foods has been emphasized due to their beneficial effects on cardiovascular diseases, which are the main cause of death in occidental countries, as described by literature. In order to obtain more information about the fatty acid composition of the main marine species fat constituent, usually consumed by Eastern Island population, seven fish species were analyzed: Maito (Acanthurus leucopareius), Matuko (Bodianus vulpinus), Marau (Myripristis tiki), Nanue (Kiphosus bigibus). Moki (Mori and Marari, Anampses caeruleopunctatus), Puia (Girellops nebulosus) and Raea (Cheilodactilus plessisi). Fatty acid profile and proximate analysis were determined for each species. According to its fat content, Nanue and Marari showed the highest lipid percentage, with values of 2.8 and 3.6% respectively. Fatty acid profile expressed as methyl esters percentage indicated that the most important group was that of the saturated fatty acids (SFA 35.1-54%), followed by the polyunsaturated fatty acids group (PUFA, 22-42.5%). Palmitic acid was the most important between saturated fatty acids, while oleic acid was the main fatty acid between the monounsaturated group. In omega-3 family fatty acids, eicosapentaenoic acid (EPA, C20:5w3) and docosahexaenoic acid (DHA, C22:6w3) were the most important, with values in a range between 2.0-12% and 1.8-18.3%, respectively. Omega-6 family showed a higher content in arachidonic acid (AA, C20:4w6) with values between 1.9 and 10%. Considering the fatty acid composition and the fat content, Marari was the highest in w-3 and w-6 fatty acid contribution, with values of 850 and 240 mg per one hundred grams of edible portion respectively.

Animals↗
PubMed1999

Hypertrophic discoid lupus erythematosus of the conjunctiva.

PURPOSE: To report the ophthalmic manifestations of hypertrophic discoid lupus erythematosus of the conjunctiva. METHOD: Case report and review of biopsy results. RESULTS: A 58-year-old woman with a history of chronic blepharoconjunctivitis presented with an unusual raised conjunctival lesion. Previous biopsy slides were reviewed and interpreted as diagnostic of discoid lupus erythematosus, hypertrophic or verrucous type. Both blepharoconjunctivitis and the raised conjunctival lesion resolved with hydroxychloroquine therapy. CONCLUSIONS: A raised conjunctival mass in the context of refractory blepharoconjunctivitis should elicit suspicion for discoid lupus erythematosus. The hypertrophic variant of this disease can affect the conjunctiva.

Biopsy↗
PubMed1998

Establishment of a rabbit model of extrascleral extension of ocular melanoma.

PURPOSE: To establish an animal model of extrascleral extension of choroidal melanoma. METHODS: Pigmented choroidal tumors were established in nine New Zealand albino rabbit eyes using B16F10 melanoma cell line. The sclerotomy site was not closed in the subgroup of six rabbits where extrascleral extension was desired. For the control group, the sclerotomy site was sutured with 8-0 nylon. Animals were treated with daily injections of cyclosporine and followed by serial fundus examinations, color Doppler imaging, and fundus photography. All tumor-bearing eyes were enucleated at the end of the follow-up period and examined for extrascleral extension. RESULTS: Extrascleral extension of choroidal melanoma occurred in all six animals with open sclerotomy sites. No extrascleral extension was observed in the control group. Color Doppler imaging identified extrascleral extension which was confirmed on gross histology. CONCLUSIONS: Our animal model of extrascleral extension of choroidal melanoma requires minimal surgery to establish, and is reproducible and easy to follow with standard diagnostic equipment.

Animals↗
PubMed1998

Posttransplantation lymphoproliferative disorder in the knee.

Lymphoproliferative disorders with primary presentation in a joint are extremely rare. Posttransplantation lymphoproliferative disorders are commonly extranodal at presentation but rarely involve joint structures. The authors describe a fatal case of posttransplantation lymphoproliferative disorder presenting in the knee of a 39-year-old woman who had undergone renal transplantation many years before.

Amyloidosis↗
PubMed1997

Magnetic resonance imaging of cyclodialysis clefts.

BACKGROUND: Our purpose was to determine whether cyclodialysis clefts can be imaged with magnetic resonance imaging (MRI). METHODS: Surgical cyclodialysis clefts extending approximately 3 clock hours were created in four New Zealand white rabbits. Eyes were scanned with an ocular MRI coil. Images obtained after intravenous gadolinium, topical godalinium, and gadolinium injected into the cleft were compared to images obtained without contrast. Two human eyes were also scanned for cyclodialysis clefts with MRI. RESULTS: Direct injection of gadolinium into the suprachoroid space yielded definitive localization and delineation of the cyclodialysis cleft. Cyclodialysis clefts could also be imaged following enhancement with topical or intravenous gadolinium. Without contrast medium, the clefts could not be clearly identified in rabbits. In a patient with hypotony and choroidal effusion following cataract surgery, a cyclodialysis cleft and enhancement of the suprachoroidal space were found with intravenous administration of gadolinium. MRI from a patient with a trabeculo-suprachoroidal shunt also demonstrated gadolinium enhancement of the suprachoroidal space. CONCLUSION: Cyclodialysis clefts can be imaged using gadolinium-enhanced MRI in rabbits and humans.

Aged↗
PubMed1997

A study of topical nonsteroidal anti-inflammatory drops and no pressure patching in the treatment of corneal abrasions. Corneal Abrasion Patching Study Group.

OBJECTIVE: To evaluate the effectiveness of an ophthalmic nonsteroidal anti-inflammatory drug (NSAID) in the treatment of noninfected, non-contact lens-related, traumatic corneal abrasions and no pressure patch. DESIGN: A single-center, randomized, double-masked, placebo-controlled study. PARTICIPANTS: One hundred patients with noninfected, non-contact lens-related, traumatic or foreign body removal-related corneal abrasions less than 36 hours in duration. INTERVENTION: All patients received a cycloplegic drop and erythromycin or polymyxin B (Polysporin Ophthalmic Ointment, Burroughs Wellcome, Research Triangle Park, NC). Patients were then randomized to receive either ketorolac tromethamine 0.5% ophthalmic solution or control vehicle drops. MAIN OUTCOME MEASURES: The main outcome measures were six subjective symptoms monitored daily, evaluation of corneal abrasion, and determination of adverse events. Long-term complications were determined 3 to 8 months after randomization. RESULTS: Twelve patients were excluded from the study. One day after randomization, patients receiving ketorolac tromethamine 0.5% ophthalmic solution noted significantly decreased levels of pain (P < 0.002), photophobia (P < 0.009), and foreign body sensation (P < 0.003) as compared with the control vehicle group. In addition, the time to resumption of normal activities was shorter in the group who received ketorolac tromethamine 0.5% ophthalmic solution (P < 0.001). There was no statistical difference in the amount of tearing, healing time, acuity changes, or complication rates between the two groups. CONCLUSIONS: Ketorolac tromethamine 0.5% ophthalmic solution provides increased patient comfort without clinical adverse effects when used as adjunctive therapy in the treatment of noninfected, non-contact lens-related, traumatic corneal abrasions.

Adult↗
PubMed1995

Ciliary body neurilemoma. Unusual clinical findings intimating the diagnosis.

BACKGROUND: Neurilemomas (schwannomas) rarely occur intraocularly. When present, they pose a diagnostic dilemma for the physician and often are mistaken as a malignant lesion, resulting in enucleation. METHODS: The authors report the clinical findings of a 46-year-old man with a slowly progressive growing mass of the anterior chamber, associated with glaucoma and the development of cataract. To further delineate the tumor's features, ancillary techniques, including ultrasonography, computed tomography, and magnetic resonance imaging, were conducted. A definitive anterior chamber biopsy of the tumor was performed with histologic examination and electron microscopy. RESULTS: Ultrasonography, high-resolution computed tomography and magnetic resonance imaging showed a well-delineated mass of the inferior ciliary body involving nearly 5 clock hours of the angle. Two clinical features that suggested a longstanding tumor were brilliant transillumination of the mass (leading to the impression of a "cystic mass," not corroborated by ultrasonography) and retrodisplacement of the involved iris root. The histology, and particularly the electron microscopic features, confirmed the diagnosis of a neurilemoma, a benign tumor of the anterior segment. CONCLUSION: Intraocular neurilemomas are extremely rare tumors. Few are well documented with modern ancillary techniques. Clinical findings in conjunction with radiographic and ultrasonic features may support the diagnosis of a benign tumor. For this patient, confirmation via biopsy permitted combined cataract and glaucoma surgery to rehabilitate the eye, which retains 20/20 visual acuity 3 years after the procedure.

Anterior Chamber↗