Patient opinion of analgesia during external cephalic version at term in singleton pregnancy.

To assess the opinion and the level of satisfaction of patients concerning analgesia during external cephalic version (ECV), we present the results of a survey of 120 women undergoing ECV at term during a randomised controlled trial (July 2012 to February 2013) comparing remifentanil and nitrous oxide. Overall, 110 (91.7%) women said they would repeat the procedure and 111 (92.5%) that they would recommend it to another pregnant woman, with no significant differences by type of analgesia. The administration and sense of comfort were rated better in the remifentanil group (p < .01). In conclusion, the use of analgesia during ECV is associated with a high rate of willingness among women to repeat the procedure and recommend it to other pregnant women.Impact statementWhat is already known on this subject? ECV is commonly a painful manoeuvre for the woman. This pain triggers maternal reactive abdominal muscle contraction and involuntary abdominal tensing, reducing the likelihood of successful version and causing some women to reject the technique.What do the results of this study add? The use of analgesia during ECV is associated with a high rate of willingness among women to repeat the procedure and recommend it to other pregnant women. The sense of comfort during ECV was also significantly better in the remifentanil group, probably because of its greater analgesic power and greater comfort during its administration.What are the implications of these findings for clinical practice and/or further research? ECV should be carried out under analgesia, when available, not only to decrease pain but also to encourage wider adoption of the technique and enable more women to benefit from it.

Induction of labor in breech presentation at term: a retrospective cohort study.

OBJECTIVE: To compare the outcome of two methods of labor induction and spontaneous onset of labor in breech presentation at term. MATERIAL: A retrospective study between 2003 and 2012. We compare obstetric (indication of induction, Bishop score, cesarean rate) and perinatal outcomes (Apgar score, umbilical artery pH, base excess ≤-12 mmol/L, admission to neonatal unit) between prostaglandins and oxytocin. We also compare labor induction versus spontaneous onset of labor. RESULTS: Of the 1684 breech deliveries, we carried out labor induction in 221 cases (76% with prostaglandins, 24% with oxytocin). The prostaglandins group had significantly lower Bishop scores and the time for induction phase was significantly higher. There were no differences in cesarean rate between both methods of induction or spontaneous onset of labor. The prostaglandins group had higher rates of base excess ≤-12 mmol/L. Compared with spontaneous onset of labor in breech presentation, induction had significant lower rates of newborn weight and higher rates of admission to the neonatal unit. CONCLUSIONS: Induction of labor in breech presentation at term is a reasonable and effective option after a careful selection of cases. It was not associated with an increase of perinatal morbidity or cesarean rate compared with spontaneous onset of labor.

Increased pain relief with remifentanil does not improve the success rate of external cephalic version: a randomized controlled trial.

INTRODUCTION: Our objective was to compare the effect of two pain relief methods (remifentanil vs. nitrous oxide) on the success rate of external cephalic version. MATERIAL AND METHODS: We conducted a randomized open label parallel-group controlled single-center clinical trial with sequential design, at Cruces University Hospital, Spain. Singleton pregnancies in noncephalic presentation at term that were referred for external cephalic version were assigned according to a balanced (1:1) restricted randomization scheme to analgesic treatment with remifentanil or nitrous oxide during the procedure. The primary endpoint was external cephalic version success rate. Secondary endpoints were adverse event rate, degree of pain, cesarean rate and perinatal outcomes. RESULTS: The trial was stopped early after the second interim analysis due to a very low likelihood of finding substantial differences in efficacy (futility). The external cephalic version success rate was the same in the two arms (31/60, 51.7%) with 120 women recruited, 60 in each arm. The mean pain score was significantly lower in the remifentanil group (3.2 ± 2.4 vs. 6.0 ± 2.3; p < 0.01). No differences were found in external cephalic version-related complications. There was a trend toward a higher frequency of adverse effects in the remifentanil group (18.3% vs. 6.7%, p = 0.10), with a significantly higher incidence rate (21.7 events/100 women vs. 6.7 events/100 women with nitrous oxide, p = 0.03). All reported adverse events were mild and reversible. CONCLUSIONS: Remifentanil for analgesia decreased external cephalic version-related pain but did not increase the success rate of external cephalic version at term and appeared to be associated with an increased frequency of mild adverse effects.

Effect of maternal intravenous fluid therapy on external cephalic version at term: a prospective cohort study.

OBJECTIVE: We sought to analyze whether maternal intravenous fluid therapy prior to external cephalic version (ECV) increases the amount of amniotic fluid and the success rate of the procedure. STUDY DESIGN: This was a prospective single-center cohort study of 200 women with a consecutive cohort of 100 pregnant women with a breech presentation at term who were administered intravenous fluid therapy with 2 L of hypotonic saline before the version attempt, compared to a control cohort of 100 pregnant women not given hydration treatment. RESULTS: The mean increase in the amniotic fluid index (AFI) after intravenous maternal hydration was 3.75 ± 2.71 cm. The amount of fluid before hydration was the only variable found to be associated with increases in amniotic fluid levels, both in absolute and relative terms (odds ratio, -0.21; 95% confidence interval, -0.37 to -0.05 and odds ratio, -4.62; 95% confidence interval, -6.17 to -3.06; P < .01, respectively). We did not observe any severe complications secondary to the intravenous fluid therapy. The ECV success rate was 43% in the study group compared to 47% in the control group (P = .67). The success rate was significantly lower the larger the relative increase in the AFI, although no correlation was found in absolute terms (χ(2) for linear trend = 0.03 and 0.34, respectively). CONCLUSION: Maternal intravenous fluid therapy with 2 L of hypotonic saline prior to ECV is an effective and safe technique for increasing the AFI. However, its use in ECV does not increase the success rate of the procedure.

Nitrous oxide for analgesia in external cephalic version at term: prospective comparative study.

OBJECTIVE: The objective of this study was to analyze the effect of using inhaled nitrous oxide (N2O) for analgesia in external cephalic version (ECV) at term on the success rate of the procedure, on pain, and on obstetric and perinatal outcomes. METHODS: A prospective comparative cohort study among 300 women with singleton pregnancy in breech presentation at term undergoing an ECV with inhaled N2O in a 50:50 mix with oxygen for analgesia and 150 ECVs with no analgesia. RESULTS: The success rate was 52.3% in the N2O cohort and 52.7% in the controls (P=0.94), whereas the median level of pain was statistically lower in women given N2O (median, 6; range, 4-7, vs. median, 7; range, 5-8; P<0.01). This improvement is mainly from a 49% decrease in severe pain. There were no significant differences in the rate of complications associated with the ECV, in the rate of cesarean sections, or in perinatal outcomes. Furthermore, there were no severe complications secondary to N2O inhalation. CONCLUSIONS: N2O inhalation at a concentration of 50% for analgesia during ECV decreases the level of severe pain experienced by women, appears to be safe both for mother and child, and has no influence on the success rate of ECV or the perinatal outcomes.

The membrane adaptor LAT is proteolytically cleaved following Fas engagement in a tyrosine phosphorylation-dependent fashion.

Engagement of the TCR (T-cell receptor) induces tyrosine phosphorylation of the LAT (linker for the activation of T-cells) adaptor, and thereby it recruits several cytosolic mediators for downstream signalling pathways. The Fas protein is essential for T-lymphocyte apoptosis, and following Fas engagement, many proteins are proteolytically cleaved, including several molecules that are important for the transduction of TCR intracellular signals. In the present study, we demonstrate that the adaptor LAT is also subject to a proteolytic cleavage in mature T-lymphocytes and thymocytes in response to Fas engagement, and also on TCR stimulation, and we identify three aspartic acid residues at which LAT is cleaved. Interestingly, these aspartic acid residues are located in proximity to several functionally important tyrosine residues of LAT, raising the possibility that their phosphorylation could modulate LAT cleavage. Consistent with that hypothesis, we show that induction of phosphorylation by pervanadate or H2O2 in Jurkat cells and thymocytes inhibits Fas-mediated cleavage of LAT. Moreover, we show that LAT proteolysis is also enhanced during anergy induction of primary human T-cells, suggesting that LAT cleavage may act as a regulator of TCR-mediated activation of T-cells and not only as a transducer of cell death promoting stimuli.

Induction at 41 weeks increases the risk of caesarean section in a hospital with a low rate of caesarean sections.

OBJECTIVE: To analyse the impact of a change in the management of prolonged pregnancies from inducing labour at 42(+0) to induction at 41(0-6). DESIGN: Retrospective cohort study. METHODS: Analysis of 3563 single pregnancies with cephalic presentation of ≥ 41 weeks of gestation delivered in Cruces University Hospital (Spain). Two cohorts were compared corresponding to before and after the change in the policy on induction. MAIN OUTCOME MEASURES: Induction rate, vaginal delivery rate, newborn morbidity and mortality. RESULTS: The overall rate of caesarean sections in the patients included in the study was 12.8% (19.5% among those induced and 8.4% among those in whom the onset of labour has been spontaneous). The caesarean section rate in cohorts 41(0-6) and 42(+0) were 14.1% and 11.4%, respectively (p=0.01). Though there were more newborns with umbilical cord blood ph<7.10 in cohort 41(0-6) than in the other group (8.7% versus 4.5%; p<0.01), no significant differences were found between cohorts in 5-min Apgar score < 7, number of admissions to the neonatal care unit or perinatal mortality. CONCLUSION: The induction of labour during week 41 in prolonged pregnancies may increase the rate of caesarean sections in hospitals with low rates of caesarean sections.

Oxytocin versus dinoprostone vaginal insert for induction of labor after previous cesarean section: a retrospective comparative study.

OBJECTIVE: To compare the efficacy and safety of two methods for induction of labor after previous cesarean section. METHODS: To compare 247 women with a previous cesarean section who were induced with a dinoprostone vaginal insert and 279 women with a previous cesarean section induced with oxytocin, between 2001 and 2008. We evaluated vaginal delivery rate, maternal morbidity and newborn morbidity and mortality. RESULTS: The overall rate of vaginal delivery was 65.2%. We did not find significant differences between induction with dinoprostone vaginal insert and oxytocin in the rate of cesarean section performed (35.6% vs. 34.1%, P=0.71). There were nine cases of uterine rupture (rate of 1.7%), of which four occurred with dinoprostone vaginal insert and five when using oxytocin (P=0.89). We found no significant differences in neonatal outcomes. CONCLUSIONS: Both tested methods appear to be equally safe and effective for induction of labor in women with a previous cesarean section.

Recombinant FSH versus highly purified FSH in intrauterine insemination: systematic review and metaanalysis.

OBJECTIVE: To compare the pregnancy rates (PRs) in intrauterine insemination (IUI) using recombinant FSH (rec-FSH) or highly purified urinary FSH (HP-FSH). DESIGN: Systematic review and metaanalysis. SETTING: University hospital. PATIENT(S): None. INTERVENTION(S): Electronic and manual searches. MAIN OUTCOME MEASURE(S): PR, per first cycle PR and per woman PR. RESULT(S): Six randomized trials (713 women, 1,581 cycles) were identified. In three the same doses of rec-FSH and HP-FSH were used ("equal dose" group), whereas in the other three the ratio HP-FSH:rec-FSH dose was 1.5. The global metaanalysis showed no differences in PRs. The PR per cycle was similar across the 1.5 ratio group (14.51% vs. 14.93%; relative risk [RR], 0.970; 95% confidence interval [CI], 0.687-1.369). However, the metaanalysis of the equal dose group, showed differences in the PR in favor of rec-FSH (16.36% vs. 12.31%; RR, 1.394; 95% CI, 1.004-1.936). Per woman PR analysis showed similar results (41.44% vs. 31.55%; RR, 1.273; 95% CI, 0.987-1.643). Per first cycle PR analysis showed a similar trend, although the difference did not reach significance (RR, 1.434; 95% CI, 0.934-2.203). CONCLUSION(S): Rec-FSH was associated with higher per cycle PR than HP-FSH, when used at the same dose, whereas the PR were similar when the dose of rec-FSH was 50% lower.

Treatment with testosterone or estradiol in melatonin treated females and males MRL/MpJ-Faslpr mice induces negative effects in developing systemic lupus erythematosus.

MRL/MpJ-Fas(lpr) mice is widely accepted as a valuable model of systemic lupus erythematosus. As described in a previous work, the incidence of lupus in this strain is determined by sex hormones, i.e., estrogens and androgens. Moreover, we reported that the immunomodulatory action of melatonin in these mice was gender-dependent probably through modulation and inhibition of sex hormones. Herein, we performed an experiment using hormone therapy, by treating female MRL-lpr mice with testosterone and males with estradiol and with melatonin. A decrease in total serum immunoglobulin (Ig)G and IgM immunoglobulin titers, anti-double-stranded DNA, and anti-CII autoantibodies in female mice treated with both melatonin and testosterone was revealed, along with an increase in pro-inflammatory cytokines [interleukin (IL)-2, IL-6, interferon-gamma, tumor necrosis factor-alpha, and IL-1beta), nitrite/nitrate and a decrease in anti-inflammatory cytokines (IL-10). Melatonin and estradiol treatment exhibited a similar effect in male mice. Autoantibody titer elevation and pro-inflammatory versus anti-inflammatory cytokine prevalence degraded all immunological parameters. Similar results were obtained when spleen and lymph node lymphocytes were cultured. Again, melatonin and testosterone treatment stimulated pro-inflammatory and reduced anti-inflammatory cytokines produced by lymphocytes in females. The effect was similar in males treated with melatonin and estradiol. In summary, we observed that although melatonin alone prevents lupus development in females, adding testosterone, increased pro-inflammatory cytokine pattern. In contrary, estradiol-treated males did not show any decrease in pro-inflammatory cytokines but showed an increase in regard to melatonin controls. These findings confirm that melatonin action in MRL/MpJ-Fas(lpr) mice could be gender-dependent through modulation of sex hormones.

Evidence for melatonin synthesis in the rat brain during development.

Melatonin production is not restricted to the pineal gland. Several extrapineal sources of this indole such as retina, Harderian gland, and immune system are well documented. Melatonin of pineal origin is not present in the rat at early stages of development. To assess the potential capacity of local melatonin synthesis by the immature brain and to gain insight into the relationship between melatonin production by the brain (without the pineal gland) and pineal gland during rat development, the melatonin content as well as the expression and activity of the melatonin-synthesizing enzymes, N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT), were studied at fetal and postnatal stages. Moreover, melatonin-membrane receptor (MT(1)) expression was also analyzed. Both, the expression and activity of NAT and HIOMT were found in the brain with significant day/night differences in enzymes activities. Additionally, melatonin content was detected in all stages showing day/night differences depending on the stage of development. The brain nocturnal melatonin content was higher than diurnal content on postnatal day 16 and in adult rats which is in accordance with the pineal melatonin synthesis. To investigate the origin of this brain melatonin, pinealectomized rats were used and we found that the developing brain produced its own melatonin. Also, MT(1) expression was detected in brain during development. These results demonstrate that, when the pineal is not yet producing melatonin, there is melatonin synthesis by the brain that could be used as protection from free radical damage and/or could exert some actions through MT(1) receptors.

Sex-dependent effect of melatonin on systemic erythematosus lupus developed in Mrl/Mpj-Faslpr mice: it ameliorates the disease course in females, whereas it exacerbates it in males.

In this study, the effect of chronic administration of melatonin on MRL/MpJ-Fas(lpr) mice has been studied. These mice spontaneously develop an autoimmune disease that has many features resembling human systemic lupus erythematosus. In fact, histological studies showed that all female mice and most male mice exhibited glomerular abnormalities, arteritic lesions, and cellular interstitial inflammatory infiltrate ranging from mild to severe patterns. Treatment with melatonin improved the histological pattern in females and worsened it in males. Moreover, female mice treated with melatonin showed a diminution of titers of total serum IgG, IgM, and anti-double-stranded DNA and anti-CII autoantibodies; a decrease in proinflammatory cytokines (IL-2, IL-6, interferon-gamma, TNF-alpha, and IL-1beta), an increase in antiinflammatory cytokines (IL-10), and a decrease in nitrite/nitrate. In male mice, treatment with melatonin exhibited the opposite effect, worsening all the immunological parameters with an elevation of titers of autoantibodies and a prevalence of proinflammatory vs. antiinflammatory cytokines. Similar results were obtained when lymphocytes from spleen and lymph nodes were cultured. Again, melatonin treatment in females decreased proinflammatory cytokines and increased antiinflammatory cytokines produced by lymphocytes; in males, the effect was the opposite. These findings suggest that melatonin action in MRL/MpJ-Fas(lpr) mice is gender dependent, probably through modulation and inhibition of sex hormones.

Mitochondrial damage induced by fetal hyperphenylalaninemia in the rat brain and liver: its prevention by melatonin, Vitamin E, and Vitamin C.

Abnormal oxidative stress was observed in hyperphenylalaninemia and other inborn errors of intermediary metabolism, owing to the accumulation of toxic metabolites, free radical production and increased LPO products. In our model of maternal hyperphenylalaninemia, pregnant rats were injected with 300 mg/kg BW l-phenylalanine (PHE) and 50 mg/kg BW p-chlorophenylalanine (PCPA) dissolved in saline. In this research study, we measured LPO-by-products, i.e., malonaldehyde (MDA) and 4-hydroxynonenal (4-HNE) and we demonstrated that maternal hyperphenylalaninemia increased both markers of oxidative stress in the brain and liver mitochondria of the pups. We also demonstrated that administration of melatonin, Vitamin E, and Vitamin C, in this order of potency, prevented the oxidative damage to the mitochondria, especially in the brain. We therefore conclude that maternal hyperphenylalaninemia induces a clear state of oxidative stress that is somehow directly involved in brain and liver impairment, which can be prevented by melatonin, Vitamin E, and Vitamin C.

Melatonin prevents hyperhomocysteinemia and neural lipid peroxidation induced by methionine intake.

This study was designed to determine the protective effect of melatonin treatment against oxidative damage in rat brain induced by hyperhomocysteinemia (Hhcy). Oral administration of methionine and its degradation product, homocysteine (hcy), causes mild to moderate Hhcy. The major end-point of oxidative damage measured in this report was lipid peroxidation (LPO). The levels of malondialdehyde (MDA) were assayed as index of lipid peroxidation. The increase in lipid peroxidation was inhibited by melatonin. Rats were divided into seven groups: one was used as control and each remaining group was supplemented with methionine dissolved and added to the drinking water daily for 4 weeks (0.5, 1, 1.5, 2, 3 g /kg BW). Additional groups of rats were given both melatonin (30 mg/kg BW) and methionine in drinking water daily. At the conclusion of the study, MDA levels were significantly increased in the brains of methionine-treated rats compared with control rats, whereas melatonin prevented the increases in MDA levels. Plasma hcy levels in animals treated with melatonin were significantly lower than those of controls. Melatonin lowered plasma hcy levels and could potentially be beneficial in prevention of neurodegeneration caused by mild hyperhomocysteinemia.

Melatonin synthesis and melatonin-membrane receptor (MT1) expression during rat thymus development: role of the pineal gland.

To gain insight into the relationship between thymus and pineal gland during rat development, the melatonin content as well as the activity and expression of the two key enzymes for melatonin biosynthesis, i.e. N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT), were studied in the thymus at fetal and postnatal stages. Moreover, melatonin-membrane receptor (MT1) expression was also analyzed. We found both the expression and activity of thymic NAT and HIOMT at 18 days of fetal life. Additionally, there is production of melatonin in the thymus as well as MT1 expression at this fetal age. These results show values higher in day-time than at night-time. The pineal gland begins to produce significant levels of melatonin around postnatal day 16, and this synthesis shows a circadian rhythm with high values during the dark period; therefore the nocturnal serum melatonin may inhibit thymic melatonin production. To document this, we report an increased melatonin content of the thymus in pinealectomized rats compared with sham-pinealectomized. In conclusion, these results show, for the first time, the presence of the biosynthetic machinery of melatonin and melatonin production in developing rat thymus and that the pineal gland may regulate this process.

Dual effect of melatonin as proinflammatory and antioxidant in collagen-induced arthritis in rats.

The aim of this study was to determine the effects of melatonin on proinflammatory status of rats with collagen-induced arthritis (CIA). CIA was induced in male Wistar rats with an emulsion of type II collagen in Freund's Incomplete Adjuvant (C-II/FIA). For 14 days, control and pinealectomized rats received a subcutaneous injection of 100 microL melatonin (30 microg) or vehicle (saline on 1% ethanol). Levels of cytokines interleukin (IL)-1beta and IL-6 were determined in the serum, peripheral blood mononuclear cells, and joints. Levels of anti-type II collagen antibody, nitrite/nitrate, and lipid peroxidation (LPO) were determined in the serum, joints, and brain. Treatment with melatonin significantly increased the levels of IL-1beta, IL-6, nitrite/nitrate and LPO in joints. However, melatonin significantly reduced the levels of nitrite/nitrate and LPO in serum and brain. Moreover, CIA in pinealectomized rats presented significantly reduced levels of IL-1beta and IL-6, titers of anti-type II collagen antibodies, levels of nitrite/nitrate, and LPO in joints but elevated levels in serum and brain. Melatonin has been described as a proinflammatory and antioxidant agent. In a process of inflammation as CIA, melatonin acts with a markedly proinflammatory effect at local and peripheral levels maintaining its antioxidant effect only at peripheral level.

One versus two inseminations per cycle in intrauterine insemination with sperm from patients' husbands: a systematic review of the literature.

OBJECTIVE: To study the efficacy of performing two inseminations per cycle in IUI with husband's sperm compared with one insemination per cycle. DESIGN: Meta-analysis. SETTING: Randomized and prospective trials comparing two inseminations vs. one insemination per cycle in IUI with husband's sperm, retrieved by MEDLINE and Cochrane Library searches (1966-2001) and a manual search of the abstracts of the European Society of Human Reproduction and Embryology and American Society for Reproductive Medicine annual meetings (1990-2001). PATIENT(S): A total of 865 patients underwent 1156 cycles of IUI with husband's sperm. INTERVENTION(S): After different ovarian stimulation protocols, one or two inseminations were performed. MAIN OUTCOME MEASURE(S): Pregnancy rate per cycle. Detected studies were tested for homogeneity. Because heterogeneity was observed, DerSimonian-Laird relative risk with alleatory effects was used. RESULT(S): Six randomized and prospective trials involving 865 patients and 1156 cycles were identified. There was remarkable heterogeneity among the different studies concerning methodology, especially regarding ovarian cycle management and the timing of inseminations. Although the pregnancy rate per cycle was somewhat higher in the two-inseminations-per-cycle group (14.9% vs. 11.4%), there were no statistically significant differences (relative risk = 1.34; 95% confidence interval 0.90-1.99). CONCLUSION(S): No significant differences were observed when two inseminations per cycle were performed, compared with one insemination. There was great heterogeneity concerning ovarian management and insemination timing. This heterogeneity hampered the analysis. We detected a better pregnancy rate with two inseminations vs. one insemination when clomiphene citrate with or without gonadotropins and 5000 IU of hCG were used. More studies are necessary to ascertain whether this is true or merely an artifact from the multiple subgroups analysis.

Melatonin prevents focal rat cerebellum injury as assessed by induction of heat shock protein (HO-1) following subarachnoid injections of lysed blood.

The present paper studies a marker of oxidative stress such as heme oxygenase-1 (HO-1), the main heat shock protein. HO-1 expression was induced in the focal region of the cerebellum following experimental subarachnoid hemorrhage (SAH). Lysed blood was injected into the subarachnoid space or cisterna magna region of adult rats. The experimental groups used were: (1) animals injected with lysed blood alone; (2) animals injected with saline alone; (3) lysed blood plus melatonin (10 mg/kg body weight(BW)); (4) lysed blood plus melatonin (10 mg/kg BW injected 1 h before SAH); (5) lysed blood plus melatonin (5 mg/kg BW injected 1 h before SAH); (6) lysed blood plus vitamin E (Trolox; 30 mg/kg BW injected simultaneously); (7) lysed blood plus vitamin E (30 mg/kg BW injected 1 h before SAH); and (8) lysed blood plus vitamin E (15 mg/kg BW injected 1 h before SAH). Animals were sacrificed 24 h later. Injection of lysed blood induced an overexpression of HO-1. Both, melatonin and vitamin E were able to prevent the expression of the heat shock protein. However, in terms of efficiency, the antioxidant capability of melatonin was clearly higher than that exhibited by vitamin E. The results presented in this study show that antioxidants, especially melatonin, prevent focal regions of injury as assessed by heat shock protein expression in a rat model of SAH.

Oxidative stress induced by phenylketonuria in the rat: Prevention by melatonin, vitamin E, and vitamin C.

Phenylketonuria (PKU) is an autosomal recessive disorder caused by a deficiency of the phenylalanine hydroxylation system and is characterized by a block in the conversion of phenylalanine (PHE) to tyrosine. We examined the effects of maternal hyperphenylalaninemia on the morphological and biochemical development of pup rat brain and cerebellum. In our model of PKU we evaluated a number of markers of oxidative stress such as Ehrlich adducts formation, lipid peroxidation, as well as the levels of reduced and oxidized glutathione, and the activities of the enzymes glutathione peroxidase and glutathione reductase. We also studied the expression of heme-oxigenase-1 and mitogen-activated protein kinase 1/2 (MAPK 1/2) as additional markers of oxidative stress. We demonstrate that PKU strongly increased most of the oxidative stress markers studied and induced significant morphological damage. We also showed that daily administration of melatonin (20 mg/kg BW), vitamin E (30 mg/kg BW), and vitamin C (30 mg/kg BW) until delivery prevented the oxidative biomolecular damage in the rat brain and cerebellum. Although no significant differences were observed among the antioxidants studied, it should be noted that the doses of melatonin were less than those for vitamins E and C. We conclude that PKU induces a clear state of oxidative stress that is somehow involved in the brain and body damage occurring in this inborn error. Moreover, melatonin and other antioxidants are capable of preventing completely the damage induced by PKU.

Melatonin prevents the formation of pyrrolized proteins in human plasma induced by hydrogen peroxide.

This report presents a model of oxidative stress, which includes formation of pyrrolized proteins in human plasma. Pyrroles were determined using Ehrlich's reagent under acid conditions. Adduct formation in plasma proteins was induced by hydrogen peroxide (H(2)O(2)) in a dose-dependent manner. The simultaneous addition of melatonin to the incubation medium with 100 mM H(2)O(2) prevented the formation of Ehrlich adducts. This inhibitory effect of melatonin on adduct formation was significant at concentrations higher than 10 nM melatonin. When melatonin was added to the medium 60 min before adding H(2)O(2), no significant difference was observed. The effect of melatonin was also compared with other known antioxidants such as vitamin E (Trolox) and vitamin C; the order of potency of the antioxidants was melatonin>vitamin E>vitamin C. In conclusion, the results presented in this paper add new perspectives to other well known antioxidant properties of melatonin such as prevention of protein pyrrolization.