Effects of the GingivalStat approach on early gingival margin remodeling following esthetic clinical crown lengthening: A case series.

OBJECTIVES: The aim of this case series is to present the potential applications of the GingivalStat approach, that is, the use of temporary gingival stabilizers, to favor early gingival margin remodeling and prevent the occurrence of gingival rebound following esthetic clinical crown lengthening. CLINICAL CONSIDERATIONS: Four patients requiring clinical crown lengthening were treated for esthetical and functional reasons. The surgical approach included: (a) gingival margin recontouring; (b) full-thickness flap elevation; (c) osteotomy (to achieve an adequate dimension between the alveolar bone crest and the CEJ) and osteoplasty (to reduce the bone thickness and improve the buccal bone anatomic profile, where indicated); (d) temporary gingival stabilizer placement using a block-out resin or a composite (the GingivalStat approach); and (e) flap repositioning, adaptation, and suture. One- to five-year follow-ups, reported in the different case scenarios, show evidence of clinically stable gingival margins around the treated teeth. CONCLUSIONS: Within the limits of this case series, it can be concluded that the GingivalStat approach appears as a further maneuver to cope with clinical crown lengthening procedures at esthetic sites. GingivalStat seems to favor gingival margin contour remodeling during the early phase of healing as well as prevent the occurrence of gingival rebound. CLINICAL SIGNIFICANCE: GingivalStat approach may guide gingival margin remodeling and prevent gingival rebound after wound healing of sites submitted to esthetic clinical crown lengthening.

Active alcohol consumption is associated with acute-on-chronic liver failure in Hispanic patients.

BACKGROUND: Acute-on-chronic liver failure (ACLF) is a severe clinical entity associated with elevated short-term mortality. We aimed to characterize patients with decompensated cirrhosis according to presence of ACLF, their association with active alcohol intake, and long-term survival in Latin America. METHODS: Retrospective cohort study of decompensated cirrhotic in three Chilean university centers (2017-2019). ACLF was diagnosed according EASL-CLIF criteria. We assessed survival using competing-risk and time-to-event analyses. We evaluated the time to death using accelerated failure time (AFT) models. RESULTS: We included 320 patients, median age of 65.3±11.7 years old, and 48.4% were women. 92 (28.7%) patients met ACLF criteria (ACLF-1: 29.3%, ACLF-2: 27.1%, and ACLF-3: 43.4%). The most common precipitants were infections (39.1%), and the leading organ failure was kidney (59.8%). Active alcohol consumption was frequent (27.7%), even in patients with a prior diagnosis of non-alcoholic fatty liver disease (NAFLD) (16.2%). Ninety-two (28.7%) patients had ACLF (ACLF-1: 8.4%, ACLF-2: 7.8%, and ACLF-3: 12.5%). ACLF patients had a higher MELD-Na score at admission (27 [22-31] versus 16 [12-21], p<0.0001), a higher frequency of alcohol-associated liver disease (36.7% versus 24.9%, p=0.039), and a more frequent active alcohol intake (37.2% versus 23.8%, p=0.019). In a multivariate model, ACLF was associated with higher mortality (subdistribution hazard ratio 1.735, 95%CI: 1.153-2.609; p<0.008). In the AFT models, the presence of ACLF during hospitalization correlated with a shorter time to death: ACLF-1 shortens the time to death by 4.7 times (time ratio [TR] 0.214, 95%CI: 0.075-0.615; p<0.004), ACLF-2 by 4.4 times (TR 0.224, 95%CI: 0.070-0.713; p<0.011), and ACLF-3 by 37 times (TR 0.027, 95%CI: 0.006-0.129; p<0.001). CONCLUSIONS: Patients with decompensated cirrhosis and ACLF exhibited a high frequency ofactive alcohol consumption. Patients with ACLF showed higher mortality and shorter time todeath than those without ACLF.

Sintomatología depresiva y trastornos neurocognitivos en pacientes con VIH adherentes y no adherentes a TARAA: estudio transversal analítico / Depressive symptomatology and neurocognitive disorders in haart-adherent and non-adherent hiv patients: a cross-sectional analytical study

Introducción: Las personas portadoras del virus de inmunodeficiencia humana (VIH) presentan mayor comorbilidad de trastornos neurocognitivos y del ánimo que la población general. La introducción de los antirretrovirales ha disminuido significativamente la demencia asociada a VIH, relacionado a la adherencia a la terapia antirretroviral altamente activa (TARAA). Diversos estudios han demostrado la coexistencia de otros factores para explicar dicho trastorno cognitivo, tales como enfermedad neurológica previa, enfermedad psiquiátrica, consumo de drogas, nivel educativo, reserva cognitiva, entre otras. Objetivo: Determinar el grado de sintomatología depresiva, deterioro cognitivo y su relación con la adherencia a TARAA y otros factores de curso clínico en pacientes portadores de VIH en control ambulatorio. Métodos: Estudio transversal. Se incluyeron pacientes que viven con VIH adscritos al programa de infectología del Hospital Dr. Gustavo Fricke, Viña del mar, Chile. Se utilizaron datos sociodemográficos, clínicos y se aplicaron las escalas Depression in the Medicaly III Questionary, Montreal Cognitive Assesment y Morysky Green Levin Test. Resultados: Se incluyeron 29 participantes, en su mayoría hombres (86,2%) y con escolaridad técnica o profesional (86.2%). No hubo diferencias entre variables biodemográficas, depresivas ni subdimensiones cognitivos. Entre pacientes adherentes y no adherentes se encontró diferencias significativas respecto a la presencia de algún deterioro cognitivo. Conclusiones: Los resultados deben ser interpretados con cautela, dado su alcance limitado. Futuros estudios traslacionales debieran incorporar mediciones más certeras del nivel de adherencia al TARAA.

Introduction: Human immunodeficiency virus (HIV) carriers present more neurocognitive and mood disorders than the general population. The introduction of antiretrovirals has significantly lowered the incidence of HIV associated dementia, and this is related to adherence to highly active antiretroviral therapy (HAART). Several studies have shown the coexistence of other factors that could explain the cognitive disorder, such as a pre-existing neurological disease, psychiatric disease, drug consumption, level of education, cognitive reserve, and others. Objective: To determine the degree of depressive symptomatology and cognitive impairment and their relation to adherence to HAART and other factors of the clinical course of HIV carriers in outpatient supervision. Methods: Cross-sectional study. We included HIV patients in the infectious diseases program, Dr Gustavo Fricke Hospital, Viña del Mar, Chile. We used sociodemographic and clinical data and we applied the Depression in the Medically Ill questionnaire, Montreal Cognitive Assessment, and the Morysky Green Levin Test. Results: 29 patients participated, mainly men (86.2%) with technical or professional education (86.2%). There were no significant differences in sociodemographic, depressive, or cognitive subdomain variables. There were significant differences in cognitive impairment between adherents and non-adherents. Conclusions: Care should be taken with interpreting the results, given their limited scope. Future cross-sectional studies should incorporate more accurate measurements of HAART adherence.

Optimized Production of a Redox Metabolite (pyocyanin) by Pseudomonas aeruginosa NEJ01R Using a Maize By-Product.

Pseudomonas aeruginosa metabolizes pyocyanin, a redox molecule related to diverse biological activities. Culture conditions for the production of pyocyanin in a defined medium were optimized using a statistical design and response surface methodology. The obtained conditions were replicated using as substrate an alkaline residual liquid of cooked maize and its by-products. The untreated effluent (raw nejayote, RN) was processed to obtain a fraction without insoluble solids (clarified fraction, CL), then separated by a 30 kDa membrane where two fractions, namely, retentate (RE) and filtered (FI), were obtained. Optimal conditions in the defined medium were 29.6 °C, 223.7 rpm and pH = 6.92, which produced 2.21 µg mL-1 of pyocyanin, and by using the wastewater, it was possible to obtain 3.25 µg mL-1 of pyocyanin in the retentate fraction at 40 h. The retentate fraction presented the highest concentration of total solids related to the maximum concentration of pyocyanin (PYO) obtained. The pyocyanin redox behavior was analyzed using electrochemical techniques. In this way, valorization of lime-cooked maize wastewater (nejayote) used as a substrate was demonstrated in the production of a value-added compound, such as pyocyanin, a redox metabolite of Pseudomonas aeruginosa NEJ01R.

Portación de Staphylococcus aureus enterotoxigénico tipo A, en frotis nasofaríngeos en manipuladores de alimentos / Carriage of Staphylococcus aureus among food service workers

Background Staphylococcus aureus produces 11 serotypes of endotoxins that may cause food poisoning. Aim To determine the prevalence of type A enterotoxigenic Staphylococcus aureus carriage among food service workers in Chillan, Chile. Material and Methods Pharyngeal swabs were obtained from 100 food service workers and were cultured in Agar plates. After identifying the presence of Staphylococcus aureus, DNA was extracted to identify type A toxin by conventional PCR. Results Thirty eight percent of samples were colonized with Staphylococcus aureus. Among these, 26% were toxin A producers. Conclusions Half of the sampled workers carried Staphylococcus aureus and a quarter of these produced type A enterotoxin.

Deciphering the Function of the Blunt Circadian Rhythm of Melatonin in the Newborn Lamb: Impact on Adrenal and Heart.

Neonatal lambs, as with human and other neonates, have low arrhythmic endogenous levels of melatonin for several weeks until they start their own pineal rhythm of melatonin production at approximately 2 weeks of life. During pregnancy, daily rhythmic transfer of maternal melatonin to the fetus has important physiological roles in sheep, nonhuman primates, and rats. This melatonin rhythm provides a circadian signal and also participates in adjusting the physiology of several organs in preparation for extrauterine life. We propose that the ensuing absence of a melatonin rhythm plays a role in neonatal adaptation. To test this hypothesis, we studied the effects of imposing a high-amplitude melatonin rhythm in the newborn lamb on (1) clock time-related changes in cortisol and plasma variables and (2) clock time-related changes of gene expression of clock genes and selected functional genes in the adrenal gland and heart. We treated newborn lambs with a daily oral dose of melatonin (0.25 mg/kg) from birth to 5 days of age, recreating a high-amplitude melatonin rhythm. This treatment suppressed clock time-related changes of plasma adrenocorticotropic hormone, cortisol, clock gene expression, and functional genes in the newborn adrenal gland. In the heart, it decreased heart/body weight ratio, increased expression of Anp and Bnp, and resulted in different heart gene expression from control newborns. The interference of this postnatal melatonin treatment with the normal postnatal pattern of adrenocortical function and heart development support a physiological role for the window of flat postnatal melatonin levels during the neonatal transition.

[Carriage of Staphylococcus aureus among food service workers]. / Portación de Staphylococcus aureus enterotoxigénico tipo A, en frotis nasofaríngeos en manipuladores de alimentos.

Background Staphylococcus aureus produces 11 serotypes of endotoxins that may cause food poisoning. Aim To determine the prevalence of type A enterotoxigenic Staphylococcus aureus carriage among food service workers in Chillan, Chile. Material and Methods Pharyngeal swabs were obtained from 100 food service workers and were cultured in Agar plates. After identifying the presence of Staphylococcus aureus, DNA was extracted to identify type A toxin by conventional PCR. Results Thirty eight percent of samples were colonized with Staphylococcus aureus. Among these, 26% were toxin A producers. Conclusions Half of the sampled workers carried Staphylococcus aureus and a quarter of these produced type A enterotoxin.

Synthesis of nanostructured porous silica coatings on titanium and their cell adhesive and osteogenic differentiation properties.

Nanostructured porous silica coatings were synthesized on titanium by the combined sol-gel and evaporation-induced self-assembly process. The silica-coating structures were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and nitrogen sorptometry. The effect of the nanoporous surface on apatite formation in simulated body fluid, protein adsorption, osteoblast cell adhesion behavior, and osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) is reported. Silica coatings with highly ordered sub-10 nm porosity accelerate early osteoblast adhesive response, a favorable cell response that is attributed to an indirect effect due to the high protein adsorption observed on the large-specific surface area of the nanoporous coating but is also probably due to direct mechanical stimulus from the nanostructured topography. The nanoporous silica coatings, particularly those doped with calcium and phosphate, also promote the osteogenic differentiation of hBMSCs with spontaneous mineral nodule formation in basal conditions. The bioactive surface properties exhibited by the nanostructured porous silica coatings make these materials a promising alternative to improve the osseointegration properties of titanium dental implants and could have future impact on the nanoscale design of implant surfaces.

Impact of Maternal Melatonin Suppression on Amount and Functionality of Brown Adipose Tissue (BAT) in the Newborn Sheep.

In human and sheep newborns, brown adipose tissue (BAT) accrued during fetal development is used for newborn thermogenesis. Here, we explored the role of maternal melatonin during gestation on the amount and functionality of BAT in the neonate. We studied BAT from six lambs gestated by ewes exposed to constant light from 63% gestation until delivery to suppress melatonin (LL), six lambs gestated by ewes exposed to LL but receiving daily oral melatonin (12 mg at 1700 h, LL + Mel) and another six control lambs gestated by ewes maintained in 12 h light:12 h dark (LD). Lambs were instrumented at 2 days of age. At 4-6 days of age, they were exposed to 24°C (thermal neutrality conditions) for 1 h, 4°C for 1 h, and 24°C for 1 h. Afterward, lambs were euthanized and BAT was dissected for mRNA measurement, histology, and ex vivo experiments. LL newborns had lower central BAT and skin temperature under thermal neutrality and at 4°C, and higher plasma norepinephrine concentration than LD newborns. In response to 4°C, they had a pronounced decrease in skin temperature and did not increase plasma glycerol. BAT weight in LL newborns was about half of that of LD newborns. Ex vivo, BAT from LL newborns showed increased basal lipolysis and did not respond to NE. In addition, expression of adipogenic/thermogenic genes (UCP1, ADBR3, PPARγ, PPARα, PGC1α, C/EBPß, and perilipin) and of the clock genes Bmal1, Clock, and Per2 was increased. Remarkably, the effects observed in LL newborns were absent in LL + Mel newborns. Thus, our results support that maternal melatonin during gestation is important in determining amount and normal functionality of BAT in the neonate.

Impact of chronodisruption during primate pregnancy on the maternal and newborn temperature rhythms.

Disruption of the maternal environment during pregnancy is a key contributor to offspring diseases that develop in adult life. To explore the impact of chronodisruption during pregnancy in primates, we exposed pregnant capuchin monkeys to constant light (eliminating the maternal melatonin rhythm) from the last third of gestation to term. Maternal temperature and activity circadian rhythms were assessed as well as the newborn temperature rhythm. Additionally we studied the effect of daily maternal melatonin replacement during pregnancy on these rhythms. Ten pregnant capuchin monkeys were exposed to constant light from 60% of gestation to term. Five received a daily oral dose of melatonin (250 µg kg/body weight) at 1800 h (LL+Mel) and the other five a placebo (LL). Six additional pregnant females were maintained in a 14∶10 light:dark cycles and their newborns were used as controls (LD). Rhythms were recorded 96 h before delivery in the mother and at 4-6 days of age in the newborn. Exposure to constant light had no effect on the maternal body temperature rhythm however it delayed the acrophase of the activity rhythm. Neither rhythm was affected by melatonin replacement. In contrast, maternal exposure to constant light affected the newborn body temperature rhythm. This rhythm was entrained in control newborns whereas LL newborns showed a random distribution of the acrophases over 24-h. In addition, mean temperature was decreased (34.0±0.6 vs 36.1±0.2°C, in LL and control, respectively P<0.05). Maternal melatonin replacement during pregnancy re-synchronized the acrophases and restored mean temperature to the values in control newborns. Our findings demonstrate that prenatal melatonin is a Zeitgeber for the newborn temperature rhythm and supports normal body temperature maintenance. Altogether these prenatal melatonin effects highlight the physiological importance of the maternal melatonin rhythm during pregnancy for the newborn primate.

Use of pyrogallol red and pyranine as probes to evaluate antioxidant capacities towards hypochlorite.

Hypochlorite is a strong oxidant able to induce deleterious effects in biological systems. The goal of this work was to investigate the use of PGR and PYR as probes in assays aimed at evaluating antioxidant activities towards hypochorite and apply it to plant extracts employed in Chilean folk medicine. The consumption of PGR and PYR was evaluated from the decrease in the visible absorbance and fluorescence intensity, respectively. Total phenolic content was determined by the Folin Ciocalteau assay. PGR and PYR react with hypochlorite with different kinetics, being considerably faster the consumption of PGR. Different stoichiometric values were also determined: 0.7 molecules of PGR and 0.33 molecules of PYR were bleached per each molecule of added hypochlorite. Both probes were protected by antioxidants, but the rate of PGR bleaching was too fast to perform a kinetic analysis. For PYR, the protection took place without changes in its initial consumption rate, suggesting a competition between the dye and the antioxidant for hypochlorite. Plant extracts protected PYR giving a PYR-HOCl index that follows the order: Fuchsia magellanica ≈ Marrubium vulgare ≈ Tagetes minuta > Chenopodium ambrosoides ≈ Satureja montana > Thymus praecox. Based on both the kinetic data and the protection afforded by pure antioxidants, we selected PYR as the best probe. The proposed methodology allows evaluating an antioxidant capacity index of plant extracts related to the reactivity of the samples towards hypochlorite.

Low 2-methoxyestradiol levels at the first trimester of pregnancy are associated with the development of pre-eclampsia.

OBJECTIVE: To determine whether maternal plasma levels of 2-methoxyestradiol (2-ME) are decreased early in pregnancies that subsequently develop pre-eclampsia (PE) and whether this difference could be attributed to the presence of Val158Met catechol-O-methyltransferase (COMT) polymorphism in the placenta. METHODS: Clinical characteristics and plasma samples were collected at 11 to 14 weeks prospectively in a cohort of patients. From them, 13 PE and 72 control pregnant women were chosen. Plasma soluble fms-like tyrosine kinase1 and placental growth factor levels were measured by electrochemiluminescence and 2-ME was measured by high-performance liquid chromatography with mass spectrometry/mass spectrometry detection. At delivery, placental tissue was collected and the Val158Met COMT polymorphism was determined by restriction fragment length polymorphism-PCR. RESULTS: At 11 to 14 weeks, patients who would develop PE have significantly lower plasma levels of 2-ME than controls [1.9 ± 2 standard error of the mean (SEM) vs 61.7 ± 27 pg/mL, P < 0.05]. The Val158Met polymorphism was more frequent in controls than in PE patients and the placental presence of COMT polymorphism was associated with a decreased risk of developing PE [PE: 23.1% vs control: 66.6%; χ(2) = 10.9, p = 0.0041]. CONCLUSIONS: Lower plasma concentrations of 2-ME during early pregnancy in patients who subsequently develop PE were found. Presence of placental Val158Met COMT polymorphism is associated with a decreased risk to develop PE, suggesting a protective role against PE.

Preparation and bioactive properties of novel bone-repair bionanocomposites based on hydroxyapatite and bioactive glass nanoparticles.

Bionanocomposites based on ceramic nanoparticles and a biodegradable porous matrix represent a promising strategy for bone repair applications. The preparation and bioactive properties of bionanocomposites based on hydroxyapatite (nHA) and bioactive glass (nBG) nanoparticles were presented. nHA and nBG were synthesized with nanometric particle size using sol-gel/precipitation methods. Composite scaffolds were prepared by incorporating nHA and nBG into a porous alginate (ALG) matrix at different particle loads. The ability of the bionanocomposites to induce the crystallization of the apatite phase from simulated body fluid (SBF) was systematically evaluated using X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray analysis, and Fourier transform infrared spectroscopy. Both nHA/ALG and nBG/ALG composites were shown to notably accelerate the process of crystallization and growth of the apatite phase on the scaffold surfaces. For short immersion times in SBF, nBG (25%)-based nanocomposites induced a higher degree of apatite crystallization than nHA (25%)-based nanocomposites, probably due to the more reactive nature of the BG particles. Through a reinforcement effect, the nanoparticles also improve the mechanical properties and stability in SBF of the polymer scaffold matrix. In addition, in vitro biocompatibility tests demonstrated that osteoblast cells are viable and adhere well on the surface of the bionanocomposites. These results indicate that nHA- and nBG-based bionanocomposites present potential properties for bone repair applications, particularly oriented to accelerate the bone mineralization process.

Melatonina inhibe la respuesta de cortisol a ACTH: posible mediación a través del gen reloj Per1 / Melatonin inhibition of the cortisol response to ACTH may be exerted through period circadian protein homolog 1 (Per1)

Background: Circadian cortisol production results from the interaction of the circadian production of ACTH, the autonomic nervous system and intrinsic factors within the gland. An additional regulator is the neuro-hormone melatonin. In human adrenal gland cultures, melatonin inhibited ACTH stimulated cortisol production and Per1 mRNA expression. ACTH actions on the adrenal involve early and late responses. Aim: To investigate the effects of melatonin on the time course of ACTH stimulated cortisol production and of Per1 expression in the lamb adrenal gland. Material and Methods: Adrenal glands and plasma of five newborn lambs were obtained. Adrenal glands were cut in 15 mg explants. Three of these explants were stored for RNA extraction. The rest of explants were using in different culture protocols with ACTH and melatonin. Results: Lambs had an in vivo a circadian variation in plasma cortisol and in adrenal Per1 expression. In vitro, ACTH stimulated an early and late increase in cortisol production and an early increase in Per1 expression reaching a maximum at 3 hours of treatment. Melatonin inhibited the early Per1 response to ACTH without affecting the early ACTH stimulated cortisol production. However, melatonin inhibited the late response of cortisol production to ACTH. Conclusions: The inhibitory actions of melatonin on Per1 response to ACTH may contribute to the inhibitory effects of melatonin on adrenal steroidogenic response to ACTH.

Pathogenesis of preeclampsia: the genetic component.

Preeclampsia (PE) is one of the main causes of maternal and fetal morbidity and mortality in the world, causing nearly 40% of births delivered before 35 weeks of gestation. PE begins with inadequate trophoblast invasion early in pregnancy, which produces an increase in oxidative stress contributing to the development of systemic endothelial dysfunction in the later phases of the disease, leading to the characteristic clinical manifestation of PE. Numerous methods have been used to predict the onset of PE with different degrees of efficiency. These methods have used fetal/placental and maternal markers in different stages of pregnancy. From an epidemiological point of view, many studies have shown that PE is a disease with a strong familiar predisposition, which also varies according to geographical, socioeconomic, and racial features, and this information can be used in the prediction process. Large amounts of research have shown a genetic association with a multifactorial polygenic inheritance in the development of this disease. Many biological candidate genes and polymorphisms have been examined in their relation with PE. We will discuss the most important of them, grouped by the different pathogenic mechanisms involved in PE.

Circadian rhythms in the fetus.

Throughout gestation, the close relationship between mothers and their progeny ensures adequate development and a successful transition to postnatal life. By living inside the maternal compartment, the fetus is inevitably exposed to rhythms of the maternal internal milieu such as temperature; rhythms originated by maternal food intake and maternal melatonin, one of the few maternal hormones that cross the placenta unaltered. The fetus, immature by adult standards, is however perfectly fit to accomplish the dual functions of living in the uterine environment and developing the necessary tools to "mature" for the next step, i.e. to be a competent newborn. In the fetal physiological context, organ function differs from the same organ's function in the newborn and adult. This may also extend to the developing circadian system. The information reviewed here suggests that the fetal circadian system is organized differently from that of the adult. Moreover, the fetal circadian rhythm is not just present simply as the initial immature expression of a mechanism that has function in the postnatal animal only. We propose that the fetal suprachiasmatic nucleus (SCN) of the hypothalamus and fetal organs are peripheral maternal circadian oscillators, entrained by different maternal signals. Conceptually, the arrangement produces internal temporal order during fetal life, inside the maternal compartment. Following birth, it will allow for postnatal integration of the scattered fetal circadian clocks into an adult-like circadian system commanded by the SCN.

The effects of time and dose of pregnant mare serum gonadotropin (PMSG) on reproductive efficiency in hair sheep ewes.

The aim of this study was to evaluate the effects of dose and application time of pregnant mare serum gonadotropin (PMSG) on reproductive performance of hair sheep ewes synchronized with fluorogesterone acetate (FGA) under tropical conditions of Northeastern Mexico. Ninety-nine hair ewes (63 Blackbelly and 36 Pelibuey) were treated with intravaginal sponges during 10 days. After insertion of FGA sponges, ewes were divided into four groups, and PMSG was injected intramuscularly at doses of 100, 200, and 400 IU. Relative to FGA sponge removal, PMSG was administrated at -48 h, -24 h, and at sponge removal. PMSG was not administered to the control group. Control ewes had similar (P > 0.05) lambing rate, fertility, and fecundity than those treated with 100 IU of PMSG, but lower (P < 0.05) percentages to these variables than those treated with 200 and 400 IU of PMSG. Time to estrus decreased linearly, and ovulation rate increased quadratically as PMSG dose increased (0 to 400 IU). Administration of PMSG before sponge removal increased (P < 0.01) response to estrus and decreased (P < 0.01) interval to estrus compared with control. Ovulation rate, lambing rate, fertility, and fecundity were not affected (P > 0.05) by administration time of PMSG. Both dose and time of PMSG application did not affect (P > 0.05) pregnancy rate, percentage of single and multiple lambing, and prolificacy. In conclusion, results show that the dose of 400 IU of PMSG administered before sponge withdrawal in an estrus synchronization protocol improved reproductive efficiency of hair sheep ewes.