Belief Tracking for Planning with Sensing: Width, Complexity and Approximations

We consider the problem of belief tracking in a planning setting where states are valuations over a set of variables that are partially observable, and beliefs stand for the sets of states that are possible. While the problem is intractable in the worst case, it has been recently shown that in deterministic conformant and contingent problems, belief tracking is exponential in a width parameter that is often bounded and small. In this work, we extend these results in two ways. First, we introduce a width notion that applies to non-deterministic problems as well, develop a factored belief tracking algorithm that is exponential in the problem width, and show how it applies to existing benchmarks. Second, we introduce a meaningful, powerful, and sound approximation scheme, beam tracking, that is exponential in a smaller parameter, the problem causal width, and has much broader applicability. We illustrate the value of this algorithm over large instances of problems such as Battleship, Minesweeper, and Wumpus, where it yields state-of-the-art performance in real-time.

9 Years after the first laparoscopic adjusted gastric banding (LAGB) in adolescents: the Portuguese experience

INTRODUCTION

Children all over the world are increasingly becoming overweight and obese. The experience with adults has demonstrated that surgery is the only effective way of achieving sustained weight loss in obese patients. Simultaneously, it has been proposed that bariatric surgery in the adolescent period would be a more effective treatment for childhood-onset extreme obesity rather than delaying surgery for extremely obese youth until adulthood. Nevertheless, the optimal surgical option for both adults and adolescents has yet to be established. The aim of our study was to evaluate the results of 9 years of laparoscopic adjusted gastric banding (LAGB) performed in our hospital for obesity-associated comorbidities (OAC), weight loss and surgical morbidity.

METHODS

A prospective study of all patients who underwent LAGB at our hospital between July 2001 and May 2010 was carried out. Patient selection was by a multidisciplinary team and based on the "IPEG Guideline for the Surgical Treatment of Extremely Obese Adolescents". Data were reviewed retrospectively.

RESULTS

14 patients underwent LAGB (10♀; 4♂; average age: 16 years). Preoperative BMI ranged between 41.4 and 54.6 kg/m (2). Prior to surgery, 8 different OACs were identified. 6 months later, 4 types of OAC had resolved completely and the other 4 had improved, and the improvement was maintained over time. The average excess weight (EW) loss increased from 25.7 to 48.2% at 6 and 36 months of follow-up, respectively (10 patients). At 60 and 106 months of follow-up it was 41.5% (5 patients) and 31.8% (1 patient), respectively. There were no complications arising from the surgery itself. Long-term complications were few and easily managed.

CONCLUSIONS

LAGB seems to be a good option to treat obese adolescents, as it is a minimally invasive procedure that does not radically change the patient's anatomy and is associated with minimal morbidity. It leads to a sustained improvement/resolution of OAC, and although weight loss is not continuous, it is maintained over time.

Effects of aldehydes on CD36 expression

INTRODUCTION

During the oil frying process lipid peroxidation compounds are formed. These products can modulate gene expression and alter cellular behaviour. The cellular uptake of oxidized LDL, a key step in the development of atherosclerosis, is mediated by the CD36 scavenger receptor, whose expression is down-regulated by alpha-tocopherol.

OBJECTIVE

To determine the effects of water-soluble aldehydes, obtained from thermally oxidized sunflower oil on the expression of CD36 scavenger receptor in human monocytes (THP-1 cells). We also wanted to study the effects of alpha-tocopherol on CD36 expression in the presence of water-soluble aldehydes.

MATERIALS AND METHODS

Sunflower oil was heated in a frying pan, at 180--200 degrees C for 40 min, water-soluble aldehydes were isolated, and the content of thiobarbituric acid reacting substances (TBARS) was determined. THP-1 monocytes were cultured in RPMI medium during 24 h and incubated with increasing concentrations of the water-soluble aldehydes (ranging from 0.05 to 1 microM) and with or without 50 microM of alpha-tocopherol. In parallel, THP-1 cells were cultured with the same volume of an extract obtained from non-oxidized oil or distilled water. The CD36 expression at the cell surface was studied with fluorescence-activated cell sorting (FACS).

RESULTS

Monocytes incubated in a medium containing water-soluble aldehydes, showed a dose dependent increase in the expression of the CD36 protein on the cell surface, compared to with the control groups. When the cells were treated simultaneously with 50 microM of alpha-tocopherol a significant reduction in the expression of the CD36 protein was observed.

CONCLUSION

Water-soluble aldehydes, extracted from thermally oxidized culinary oil, increase the expression of CD36. This effect is partially decreased by the presence of alpha-tocopherol.

Adipose tissue and liver lipid metabolism in obese children: role of the body mass index and the presence of acanthosis nigricans

AIMS

The aims of our study were to determine if insulin resistance is associated with increased plasma levels of non-esterified fatty acids (NEFA), glycerol, 3-hydroxybutyrate and triglycerides in obese children. We also studied whether the presence of acanthosis nigricans (AN) led to further alterations in the above parameters.

METHODS

A total of 101 children were studied on their first visit to the paediatric endocrine clinic. Seventy-four were obese, 30 of them with AN. The remaining 27 were non-obese healthy children (control group). NEFAs, glycerol, triglycerides, 3-hydroxybutyrate, insulin, leptin, adiponectin and glucose were determined in blood samples obtained after overnight fasting. The insulin resistance index (IRI) was calculated following the homeostasis model assessment (HOMA). Data from the three groups were compared using appropriate statistical tests.

RESULTS

No differences in age, sex ratio and pubertal stage were observed among the three groups. The group of children with the highest body mass index (BMI) showed higher plasma levels of insulin and leptin, higher IRI and lower plasma levels of adiponectin. As insulin and IRI increased, NEFA and 3-hydroxybutyrate decreased and triglycerides increased. When obese children were categorized by BMI, the presence of AN further exacerbated these differences.

CONCLUSIONS

In obese children, insulin resistance is associated with plasma lipid alterations suggestive of both decreased adipose tissue lipolysis and hepatic beta-oxidation and increased hepatic synthesis of triglycerides. Such a metabolic condition may facilitate fat storage and hinder weight loss.

Clastogenic and cytotoxic effects of lipid peroxidation products generated in culinary oils submitted to thermal stress

In rats, the administration of oil submitted to high temperatures is teratogenic. To understand the mechanisms involved, the clastogenic and cytotoxic effects were studied respectively in lymphocytes, hepatocytes (HepG2) and in human umbilical vein endothelial cells (HUVEC) cultured with a water extract obtained from heated oil (HO). In lymphocytes incubated with HO containing 0.075 or 0.15 microM of thiobarbituric reacting substances, the rate of chromosomal breakage was 18.4% and 23.1%, compared to 8.7% and 6.6%, or 8.1% and 9.2%, respectively in lymphocytes incubated with the same volume of a water extract from non-heated oil (NHO) or distilled water (DW). In HepG2 or HUVEC cells, the cytotoxic properties of the HO were dose dependent, the cytotoxicity beginning at concentrations as low as 0.25 microM. In contrast, the same volume of NHO or DW was non-toxic for these cells. The results obtained show that a water extract obtained from heated oil is clastogenic and, in higher doses, cytotoxic.

Long-term reversal of hypocholesterolaemia in patients with chronic hepatitis C is related to sustained viral response and viral genotype

BACKGROUND

Genotype-3 of hepatitis C virus (HCV) has been associated with serum lipid changes (reversible with sustained viral response) and liver steatosis.

AIM

To characterize the relationships among hepatic steatosis, cholesterol and sustained viral response in these patients.

METHODS

Patients (n = 215) with chronic hepatitis C (157 with genotype-1 of HCV) had age, body mass index, gender, alcohol intake, glycaemia, serum lipids, transaminases, grade and stage (METAVIR and Scheuer), degree of liver steatosis, sustained viral response, insulinaemia, leptinaemia, beta-hydroxybutyrate and glycerol measured, and were compared with 32 hepatitis B virus (HBV)-infected subjects.

RESULTS

Genotype-3 of HCV patients had age-adjusted hypocholesterolaemia and more frequent hepatic steatosis (P < 0.001). Steatosis was inversely correlated with serum cholesterol (P < 0.01) and directly with viral load (P < 0.03). In patients with genotype-3 of HCV and sustained viral response, serum cholesterol increased from 138 (95% CI: 120-151) to 180 mg/dL (95% CI: 171-199) 12 months after treatment conclusion (P < 0.0001). By contrast, cholesterol values were unchanged in genotype-3 of HCV non-responders and in patients with genotype-1 of HCV regardless of response. Rising cholesterol in sustained viral response did not parallel the changes in beta-hydroxybutyrate.

CONCLUSIONS

Besides causing hepatic steatosis, genotype-3 specifically decreases serum cholesterol. This interference with the metabolic lipid pathway is related to viral load, is reversed with sustained viral response, and seems unrelated to mitochondrial dysfunction.

[Nonpalpable testes: experience from the Hospital Central Especializado de Crianças Maria Pia]

The incidence of cryptorchidism in children at age of 1 year is 1%, and 20% of these cases represent nonpalpable testes. The aim was to evaluate the use of minimal invasive surgery for the diagnosis and therapy of these patients. The authors made a prospective, analytical and longitudinal study from January 2001 through December 2004 in 89 consecutive boys undergoing laparoscopy for 98 impalpable testes. The following details were analyzed: examination under general anesthesia, ultrasound examination, age at surgery, findings at laparoscopy, operative procedure, results of the histology and follow up.

[Reconstruction of velopharyngeal sphincter in secondary Cleft Palate: surgical alternative]

There are numerous surgical procedures for the repair of Cleft Palate (CP). Since 1998, in children with CP we use a modified Wardill-Kilner technique, with a large section of the nasal mucous layer at the level of the muscular insertion on the hard palate and lateral nasopharingeal wall, obtaining a push-back and reorientation of the muscular fibres without dissection, diminishing this way the risks of haemorrhages and fibrosis, simplifying the intervention. It allows a lower operative time and a short internment. The aim of our study was to evaluate the results of this operative procedure specially in the development of the speech in 73 children operated on from 1998 until 2000 in our hospital. We verify a competence of the velopharingeal sphincter with ideal results in speech in 88,8% of the cases.

[Minimal invasive surgical of intersex abnormalities: our experience]

The term intersex makes reference to either newborn infants who show ambiguous external genitals or those who, having a normal phenotype, show growth alterations in the puberty. The etiologic diagnostic is oriented by the physical examination, biochemical studies, radiologic, surgical techniques and histological discoveries; that enables us to decide one more accurate sex assignment; the laparoscopy plays an important role, for the direct visualisation of the intra-abdominal gonads, internal genital identification, gonadal biopsy, as well as therapeutic interventions as gonadectomy, orchidopexy and resection of Müllerian remants, replacing totally the laparotomy. The purpose of our job was evaluate the role of the minimal invasive surgical as diagnostic and treatment of the intersex, in nine intersex children treated in our hospital over the last three years.

mGPT: A Probabilistic Planner Based on Heuristic Search

We describe the version of the GPT planner used in the probabilistic track of the 4th International Planning Competition (IPC-4). This version, called mGPT, solves Markov Decision Processes specified in the PPDDL language by extracting and using different classes of lower bounds along with various heuristic-search algorithms. The lower bounds are extracted from deterministic relaxations where the alternative probabilistic effects of an action are mapped into different, independent, deterministic actions. The heuristic-search algorithms use these lower bounds for focusing the updates and delivering a consistent value function over all states reachable from the initial state and the greedy policy.

Neuroprotective effect of L-arginine in a newborn rat model of acute severe asphyxia

The left common carotid artery was ligated in anaesthetized 7-day-old Wistar rats (P7), prior to asphyxia by inhaling 100% nitrogen for 9 min. Pups recovered from asphyxia received i.p. saline (n = 16), or L-Arg 300 mg/kg (n = 14). Pups undergoing sham operation remained as controls (n = 12). At day 14, the amount of surviving or degenerating neurons was quantified under optical microscopy by Nissl technique or by Fluoro-Jade B (FJB) in CA1 area of hippocampus and in parietal cortex. In these areas, asphyxia reduced the neuronal density by 23.6 and 30%, and increased the proportion of degenerating neurons two and four times, respectively. L-Arg administration to asphyxiated pups reduced the neuronal loss and the proportion of degenerating neurons by 50% (p < 0.05). We conclude that L-Arg administration after acute severe asphyxia in newborn rats is neuroprotective, reducing early and delayed neuronal loss.

Effects of ergothioneine on diabetic embryopathy in pregnant rats

The natural antioxidant ergothioneine (2-mercaptohistidine trimethylbetaine) is a fungal metabolite and found in most plant and animal tissues. The effect of ergothioneine on diabetic embryopathy in rats was assessed. Supplementation of diabetic pregnant rats with L-ergothioneine (1.147 mg/kg body weight) daily for the first 11.5 days of pregnancy reduced the rate of embryo malformations, to values similar to the non-diabetic animals. The ergothioneine had no effect on the plasma glucose levels, both in diabetic and control animals. We conclude that the inhibition of the glucose-mediated free radical dependent embryo malformation by ergothioneine is an important antioxidant prophylactic mechanism, which when combined with vitamin E could benefit the management of diabetic embryopathy.

Effect of acipimox on plasma lipids and glucose/insulin in pregnant rats

To determine how a reduction in maternal hypertriglyceridemia during late pregnancy may affect glucose/insulin relationships, pregnant and virgin rats were orally treated with acipimox, a potent antilipolytic agent. In 20-day pregnant rats receiving 80 mg of acipimox, plasma triglycerides (TG), free fatty acids (FFA), and glycerol decreased more than in virgin rats shortly after the drug (up to 7 hours), when compared with animals treated with distilled water, whereas plasma glucose level was unaffected by the treatment in either group of rats. When acipimox was given every 12 hours from day 17 to day 20 of pregnancy, plasma TG, FFA, and glycerol levels progressively increased, whereas they either decreased or did not change in virgin rats receiving the same treatment, with no effect in plasma glucose levels in either group. Fetal body weight was lower than in controls in 20-day pregnant rats that received acipimox for 3 days. On day 20 of pregnancy, 3 hours after receiving acipimox or distilled water, rats received a 2 g glucose/kg oral load and it was found that the change in plasma glucose was similar in both groups, whereas the increase in plasma insulin was greater in pregnant rats treated with acipimox. However, no difference was found in either variable after the oral glucose load in virgin rats receiving acipimox or distilled water. No differences in plasma glucose levels were found after intravenous (i.v.) administration of insulin in pregnant rats treated or not treated with acipimox. In conclusion, present results show that administration of acipimox during the last days of gestation inhibited lipolysis and decreased fetal weight. Over a short period of time, in pregnant rats, reductions of plasma FFA and TG after acipimox treatment improved the glucose-induced insulin release, but did not seem to have any effect in peripheral insulin resistance.

Oxidative damage in pregnant diabetic rats and their embryos

Free radical mechanisms may be involved in the teratogenesis of diabetes. The contribution of oxidative stress in diabetic complications was investigated from the standpoint of oxidative damage to DNA, lipids, and proteins in the livers and embryos of pregnant diabetic rats. Diabetes was induced prior to pregnancy by the administration of streptozotocin (45 mg/kg). Two groups of diabetic rats were studied, one without any supplementation (D) and another treated during pregnancy with vitamin E (150 mg/d by gavage) (D + E). A control group was also included (C). The percentage of malformations in D rats were 44%, higher than the values observed in C (7%) and D + E (12%) animals. D Group rats showed a higher concentration of thiobarbituric acid reactive substances in the mother's liver, however, treatment with vitamin E decreased this by 58%. The levels of protein carbonyls in the liver of C, D, and D + E groups were similar. The "total levels" of the DNA adducts measured, both in liver and embryos C groups were similar to the D groups. Treatment of D groups with vitamin E reduced the levels by 17% in the liver and by 25% in the embryos. In terms of the "total levels" of DNA adducts, the embryos in diabetic pregnancy appear to be under less oxidative stress when compared with the livers of their mothers. Graziewicz et al. (Free Radical Biology & Medicine, 28:75-83, 1999) suggested "that Fapyadenine is a toxic lesion that moderately arrests DNA synthesis depending on the neighboring nucleotide sequence and interactions with the active site of DNA polymerase." Thus the increased levels of Fapyadenine in the diabetic livers and embryos may similarly arrest DNA polymerase, and in the case of this occurring in the embryos, contribute to the congenital malformations. It is now critical to probe the molecular mechanisms of the oxidative stress-associated development of diabetic congenital malformations.

[Pseudotumor cerebri associated with maxillary sinusitis: clinico-pathological study]

INTRODUCTION

The pseudotumor cerebri is characterized by increased intracranial pressure in the absence of a space occupying lesions or obstruction to the circulation of cerebrospinal fluid (CSF). Increased pressure but normal composition of the CSF is the diagnostic criterion. Ear infections and other infections such as sinusitis have been cited as possible, but rare, causes.

CLINICAL CASE

A 12 year old girl presented with diplopia 10 days after starting treatment for sinusitis. On examination there was paresia of the VI cranial nerve to the left eye and marked bilateral papilledema. She had normal visual acuity with visual field measurements showing increased blind spot field in both eyes. Resonance studies only showed maxillary sinusitis. CSF pressure was 35 cm H2O, with 40 lymphomonocytes and normal biochemical findings. After 15 cm of CSF had been removed treatment was started with acetazolamide, dexamethasone and cefotaxime. A week later the diplopia had disappeared and the CSF pressure was 25, with no cells present. Two months later the visual fields and fundus oculi were normal. After follow-up for one year there was no recurrence.

CONCLUSIONS

We describe a case of pseudotumor cerebri associated with maxillary sinusitis. We do not know whether this is a chance association or whether there was a pathophysiological basis. The possibility should be considered so as to treat the cause or predisposing factor. The initial CSF pleocytosis would support the possibility of a relationship of the pseudotumor with an infectious condition (meningeal irritation or para-infectious pleocytosis meningeal irritation or para-infections pleocytosis in the context of an ENT infection), which might have precipitated the problem by interfering with the reabsorption of CSF.

Estradiol 17beta inhibition of LDL oxidation and endothelial cell cytotoxicity is opposed by progestins to different degrees

Progestins oppose the effects of estrogens in many biological systems, but it is not known if progestins oppose the antioxidant effects of estrogen and to differing degrees. To test these questions, the effects of various sex steroids on LDL oxidation and cytotoxicity were studied in the absence or presence of endothelial cells. Freshly isolated LDL was incubated in the presence of Cu(++) in the absence or presence of cultured bovine aortic endothelial cells in phenol red-free medium and without or with hormones in 0.5% ethanol. The hormones included 17beta-estradiol (E(2)), progesterone (Pg), norgestimate (NGM), levonorgestrel (LNG), and medroxyprogesterone acetate (MPA). LDL oxidation was measured as formation of conjugated dienes, lipid peroxides, and TBARS, and cyotoxicity by tetrazolium salt reduction (MTT reduction). Progestins diminished conjugated diene lag phase, accelerated lipid peroxide and TBARS production in the absence and presence of cells and accelerated cytotoxicity. When E(2) and progestin were incubated with cells at a molar ratio of 1:5, lipid peroxides were reduced from baseline by E(2) alone 31%, E(2)/Pg 29%, E(2)/NGM 16%, E(2)/LNG 9% (all P<0.05 or more) and E(2)/MPA 8% (ns) (E(2) or E(2)E(2)/NGM, E(2)/LNG and E(2)/MPA [P<0.001]; E(2)E(2)/LNG or E(2)/MPA [P<0.05]). MTT reduction followed a similar gradient, greatest with E(2) alone, least with E(2)/MPA.

CONCLUSIONS

Progestins promote LDL oxidation and, conjointly, endothelial cell cytotoxicity. Progestins oppose the antioxidant and cytoprotective effects of estrogen when given in combination. MPA and LNG have the strongest prooxidant and cytotoxic effects, which may limit the cardiovascular benefit of estrogen during combined administration in vivo.

Opposing effects of estrogen and progestins on LDL oxidation and vascular wall cytotoxicity: implications for atherogenesis

Estrogens are widely regarded as beneficial to arterial wall health. Among the mechanisms of this benefit are antioxidant effects on LDL and the arterial wall. Because progestins oppose the effect of estrogen in several systems, we asked if progestins oppose the antioxidant effect of estrogen. To study this question, LDL and various female sex hormones were incubated alone and combined in the absence or presence of bovine aortic endothelial cells, placental trophoblast, or macrophages, and LDL oxidation and cytotoxicity were quantitated. In the absence of cells, LDL incubated with copper in phosphate-buffered saline enhanced the oxidation of LDL. When 17beta-estradiol was added to this system, an antioxidant effect was observed. Progestins inhibited this protective estrogenic effect. In endothelial cell culture, progestins also opposed the antioxidant effect of estrogen, with the strongest antiestrogenic effect seen with the synthetic progestins, levonorgestrel and medroxyprogesterone acetate (MPA). Endothelial cell cytotoxicity was proportional to the enhanced lipid peroxide formation observed with progestins or estrogen. Similar opposing effects were seen when estrogen and progesterone were added to primary cultures of placental trophoblast or macrophages. Thus, three cell culture systems modeling circulating arterial blood contact with cell surfaces demonstrated opposing effects of estrogens and progestins on LDL oxidation and cell cytotoxicity. These studies are in keeping with published reports that female sex steroids influence LDL oxidation in vivo and consequent arterial wall injury.

Alpha-tocopherol concentration in fetal and maternal tissues of pregnant rats supplemented with alpha-tocopherol

We wanted to determine whether alpha-tocopherol supplementation to pregnant rats could increase the concentration of alpha-tocopherol in maternal and fetal plasma and tissues. Pregnant rats were treated with alpha-tocopherol on days 18 and 19 gestation and studied at day 20. A control group was studied in parallel. Treatment of pregnant rats with alpha-tocopherol increased its concentration in maternal and fetal plasma, in all maternal plasma lipoprotein fractions, in maternal and fetal liver and in the placenta. The fetal and maternal concentration of alpha-tocopherol were positively correlated.

LDL oxidation and human placental trophoblast and macrophage cytotoxicity

We have previously shown that LDL is oxidized by placental cells in primary tissue culture and that this process causes cytotoxicity proportional to LDL oxidation in the presence of sex steroid hormones. Here we describe further experiments linking LDL oxidation to placental cell cytotoxicity. Trophoblast and macrophages were isolated from healthy elective caesarean section placentas by enzymatic digestion and separated by centrifugation on a 40% Percoll gradient and maintained in primary culture for up to 5 days. LDL was oxidized by exposure to 5 microM CuCl2, cells were incubated in the absence of albumen to favor oxidation, and cytotoxicity was measured by 51Cr release from prelabelled cells and cell protein content. Native LDL was oxidized by both cell types with a 10%-50% increase in lipid peroxides and an approximately 4-fold increase in TBARS formation. Increasing concentrations of native LDL and oxidized-LDL increased 51Cr release and diminished protein content in cells incubated in HAM's F-10 medium. Addition of 5 microM Cu2+ augmented cytotoxicity of LDL in macrophage and trophoblast culture, but more in macrophages than trophoblast. Cytotoxicity was diminished by adding 0.001-0.1 mM EDTA to the system, diminishing 51Cr release from 91 +/- 0.5 to 40.8 +/- 1.0% in macrophages and 54.2 +/- 1.2 to 33.1 +/- 1.3% in trophoblast (P < 0.001 in both instances). Similarly, the absence of transition metal ion in culture (MEM medium) blocked an increase in 51Cr release compared to its presence (HAM's F-10 medium). An antioxidant, butylated hydroxytoluene, diminished 51Cr release and LDL electrophoretic mobility in HAM's F-10 medium in placental macrophage culture. LDL oxidation injures placental macrophages and trophoblast, the former more than the latter. The process is LDL- and transition metal ion-dependent and is inhibited by antioxidant. This model of LDL oxidation and placental cell damage in vitro provides a basis for studying mechanisms of placental dysfunction and senescence in human pregnancy.

Antioxidant and prooxidant effects of ascorbic acid, dehydroascorbic acid and flavonoids on LDL submitted to different degrees of oxidation

Although a high intake of antioxidants may decrease the risk of developing cardiovascular diseases, under certain circumstances they may promote free radical generation and lipid peroxidation. The objectives of the present study were to determine the antioxidant effects of ascorbic acid (AA), dehydroascorbic acid (DHA) and flavonoids on LDL submitted to different degrees of oxidation. LDL was submitted to oxidation with CuCl2 (2.4 microM). Before or at different times after the propagation of the oxidation process, 28 microM (5 micrograms/ml) of either AA or DHA or 5 micrograms/mL flavonoids extract were added. Alpha-tocopherol, conjugated dienes, thiobarbituric acid reacting substances (TBARS) and LDL electrophoretic mobility were determined as indices of LDL oxidation. The presence of any of the three antioxidants from the onset of the incubation delayed the oxidation process. However, the addition of both DHA and flavonoids to the oxidation process when it was already initiated and alpha-tocopherol consumed, accelerated the oxidation. In contrast, AA delayed the oxidation process even when added after alpha-tocopherol was consumed. Nevertheless, it also accelerated LDL oxidation when added during the propagation phase of the oxidation process.

IN CONCLUSION

although AA, DHA and flavonoids delay LDL oxidation when added before the initiation of the process, they accelerate the process if added to minimally oxidized LDL.

Simultaneous determination of vitamins A and E in rat tissues by high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) method to determine vitamins A, Ap and E simultaneously was developed with direct extraction of vitamins from rat tissues with n-hexane and probe sonicating. The dry residue was redissolved in chloroform-methanol. Vitamins A and Ap were detected by UV-Vis and vitamin E by fluorescence. Vitamin K, used as internal standard, was detected both the UV-Vis and by fluorescence. Standards and samples were checked for linearity giving correlation coefficients that were higher than 0.99 in the concentration range of 3.1-9.4 for vitamin A, 8.2-24.7 for vitamin Ap and 0.6-1.7 nmol/g in the case of liver extracts and 0.5-3.0 nmol/g in the case of placenta. The inta-assay precision (R.S.D) varied between 1.48 and 7.25, whereas inter-assay precision was between 4.99 and 7.03. Recoveries ranged between 94 +/- 8 and 107 +/- 5%. Results from the application of this method to different rat tissues having wide range of vitamin content are presented.

17beta-Estradiol, progesterone, and testosterone inversely modulate low-density lipoprotein oxidation and cytotoxicity in cultured placental trophoblast and macrophages

OBJECTIVES

We have previously shown that low-density lipoprotein oxidation is diminished by 17beta-estradiol and enhanced by progesterone and testosterone. In these experiments we wished to learn whether sex hormone effects on low-density lipoprotein oxidation alter placental cell viability in primary tissue culture.

STUDY DESIGN

Primary tissue culture of human term placental cells was performed.

RESULTS

Addition of 17beta-estradiol decreased low-density lipoprotein oxidation (measured as lipid peroxides, thiobarbituric acid-reacting substances, and low-density lipoprotein electrophoretic mobility) and placental cell toxicity (measured as chromium 51 release) with maximum reductions of 28% (macrophages) (p < 0.05) and 26% (trophoblasts) (p < 0.01). Conversely, progesterone and testosterone increased low-density lipoprotein oxidation and chromium 51 release, the latter a maximum of 28% and 18%, respectively, for progesterone and testosterone in macrophages (p < 0.05 in both instances) and 23% in trophoblasts (p < 0.05, testosterone only). Collectively, cytotoxicity was proportional to low-density lipoprotein oxidation and estradiol, progesterone, and testosterone concentrations.

CONCLUSIONS

Estradiol inhibits placental macrophage- and trophoblast-mediated low-density lipoprotein oxidation and cytotoxicity, whereas progesterone and testosterone promote these effects. Sex steroid hormones may modulate the effects of oxidative stress on placental function in pregnancy.

Teratogenic effects of diabetes mellitus in the rat. Prevention by vitamin E

We wanted to determine whether administration of vitamin E could reduce the production of free radicals which could play a role in the teratogenic effects of diabetes mellitus. Diabetes was induced in Wistar rats by the intravenous administration of streptozotocin. The animals were divided into six groups: one with no supplement (D) and two, supplemented during pregnancy either with oral vitamin E (150 mg/day) (D + E) or with a placebo (safflower oil) (D + O). Three other groups were kept under the same conditions, but were treated with insulin: D + I, D + I + E and D + I + O. There were three groups of matched controls: C, C + E and C + O. All animals were killed on day 11.5 of pregnancy. In C animals the percentages of reabsorptions and malformations were 1.3 and 2%, respectively, compared with 23.6, 24.3, 6.2 and 13.2%, respectively in D and D + I groups. The crown-rump length, number of somites, and protein and DNA content were higher in C animals than in the diabetic rats, independent of insulin treatment. When vitamin E was administered no changes in these parameters were observed in C and D + I animals; however, in the D mothers it reduced the rate of embryo malformations to 4.6% and increased the crown-rump length and the number of somites. However, vitamin E did not modify the protein and DNA content and the percentage of reabsorptions. In conclusion, administration of vitamin E to diabetic animals decreases the rate of embryo malformations and increases their size and maturation, supporting a role for free radicals in the teratogenic effects of diabetes.

In vitro effects of a flavonoid-rich extract on LDL oxidation

Flavonoids are phenolic compounds of vegetable origin with antioxidant effects. The present study aimed to determine their properties as LDL antioxidants. LDL were incubated with increasing concentrations of flavonoids (0-16 micrograms/ml) and LDL oxidation was started by adding CuCl2 (2 microM) to the media. When flavonoids were present in the media, vitamin E consumption, the lag phase of conjugated diene formation, LDL electrophoretic mobility in agarose gels and the appearance of thiobarbituric acid reacting substances (TBARS) were delayed in a concentration-dependent manner. To determine whether flavonoids could terminate LDL oxidation once initiated, two sets of experiments were performed. In the first, LDL oxidation was initiated as described above. At 2 or 4 h of incubation, flavonoids were added (4 micrograms/ml) and their effect compared to samples where butylated hydroxytoluene or EDTA were added. At 5 h, in the LDL samples where flavonoids were added, the electrophoretic mobility and TBARS production were the same as those present in LDL samples incubated for the whole period in the absence of flavonoids. However, when either butylate hydroxytoluene or EDTA was added, as would be expected, the LDL oxidation process was completely arrested as shown by a reduction in the appearance of TBARS and a lower LDL electrophoretic mobility. In the second experiment, LDL oxidation was initiated as described above and at 0, 10 and 20 min, flavonoids were added (4 micrograms/ml). When vitamin E was still present in the LDL solution, the flavonoids were able to both increase the lag phase in the formation of conjugated dienes and to delay the consumption of vitamin E. The present results show that in vitro, flavonoids prevent LDL oxidation in a concentration-dependent manner, delaying the consumption of vitamin E, but they cannot terminate or delay LDL oxidation once vitamin E in LDL is consumed.

Metabolism of modified LDL by cultured human placental cells

All major classes of normal circulating lipoproteins can be metabolized by human placental cells. However, the metabolism of abnormal or modified lipoproteins has been little studied. We therefore investigated whether placental cells metabolize acetylated low density lipoprotein (ac-LDL) or oxidatively-modified LDL (ox-LDL), both of which are metabolized by scavenger receptors, and if so, whether modified LDL stimulates progesterone secretion as does normal LDL. Placental macrophages and trophoblasts were isolated on a 40% Percoll gradient after enzymatic digestion. The cellular uptake and degradation of [125I]-ac-LDL was 20-fold higher than [125I]-LDL in both macrophages and trophoblasts. Both cell types demonstrated high affinity and saturable degradation. Similarly, increased esterification of [14C]-labelled oleic acid to cholesterol was observed when cells were incubated with ac-LDL vs. LDL. Uptake of ac-LDL by trophoblasts also was demonstrated by colocalization of fluorescently labelled ac-LDL and fluorescent antibodies specific for trophoblasts. Similar colocalization of fluorescent ac-LDL and fluorescent anti-macrophage specific epitopes was seen in macrophages. Uptake and degradation of [125I]-ac-LDL by placental cells was inhibited by increasing concentrations of unlabelled ac-LDL or fucoidin but not LDL, indicating uptake by a scavenger receptor. Both unlabelled ac-LDL and ox-LDL inhibited uptake of [125I]-labelled ox-LDL, suggesting uptake by a common mechanism. Although secretion of progesterone by trophoblasts was stimulated by incubation with LDL, progesterone secretion by trophoblasts was not stimulated by ac-LDL and only minimally stimulated by ox-LDL.

CONCLUSIONS

Scavenger receptors are present in human placental trophoblasts as well as macrophages. Scavenger receptor activity greatly exceeds that of LDL receptor activity in both cell types. However, cholesterol assimilated via the scavenger receptor pathway appears to be disconnected from endocrine steroidogenesis in trophoblasts. Thus, we hypothesize that scavenger receptors function in trophoblasts to degrade modified lipoproteins and prevent toxic effects on placental cellular function and fetal growth and development.

Effects of estrogens on lipoprotein metabolism and cardiovascular disease in women

Estrogen use is associated with protection from cardiovascular disease in postmenopausal women. This benefit appears to be magnified among women with pre-existing heart disease. The possible bias of intrinsically better health in women using estrogen has not been ruled out in observational studies. Therefore, two double-blind randomized clinical trials are underway in postmenopausal women. One in women with coronary disease is known as HERS (Heart Estrogen-progestin Replacement Study) and another in predominantly healthy women is the WHI (Women's Health Initiative). Several mechanisms of estrogen mediated protection from cardiovascular disease have been identified including increased HDL, lower LDL, lower VLDL-cholesterol/triglyceride ratio, increased clearance of intermediate density lipoprotein (IDL) and LDL via an upregulated LDL receptor, diminished penetration and degradation of LDL in the arterial wall, an inhibition of LDL oxidation by various estrogens and a reversal of inappropriate acetylcholine (EDRF)-mediated vasoconstriction in arteriosclerotic vessels. The predominating mechanism is not known, but estrogen replacement therapy is both likely to be beneficial to female health, pending randomized trials, as well as a tool to understand mechanisms of prevention of coronary artery disease.

Prediction of infant birth weight by GDM screening tests. Importance of plasma triglyceride

OBJECTIVE

We measured plasma glucose, GHb, GPro, IRI and TG at 24-28-wk gestation to determine the extent of elevations in GDM and relationships to glucose intolerance and infant macrosomia.

RESEARCH DESIGN AND METHODS

Plasma samples were obtained 1 h after ingestion of 50 g glucose after an overnight fast in 521 randomly selected negative screenees, 264 positive screenees with GTT-, and 96 positive screenees with GTT+ (GDM).

RESULTS

Screening test values in GDM subjects exceeded the GTT- group, whose values exceeded those of negative screenees: glucose, 9.6*, 8.7*, 6.3 mM; GHb, 5.2*, 4.9*, 4.7%; GPro, 3.1*, 3.0*, 2.8%; IRI, 791*, 662*, 410 pM; and TG, 2.3*, 1.9, 1.9 mM, (*P < 0.005 vs. negative screenees). TG was the only test elevated in the GDM but not in the GTT- groups. Screening test values correlated with GTT values in the following order (strongest to weakest): glucose* > TG* > GHb* > IRI > GPro (*statistical significance). Plasma TG was the only screening test significantly associated with birth weight corrected for gestational age (birth-weight ratio) (r = 0.09-0.16) (P < 0.05 to < 0.01) and was of the same order as 1- and 2-h GTT associations with birth weight (r = 0.13 and 0.14, respectively) (P < 0.05 to < 0.01). Plots of TG/birth-weight ratio increased linearly to the 80-90th TG percentile in negative screenees and GTT- subjects. GDM subjects followed this trend but with more variation. Above the 90th percentile for TGs, birth-weight ratio trended lower, significantly so when the groups were combined (P < 0.05). In multivariate analysis, TG was associated with birth-weight ratio even when maternal prepregnancy weight and pregnancy weight gain associations with TG and birth-weight ratio were controlled (P < 0.019).

CONCLUSIONS

Of the five screening tests evaluated, all were elevated in GDM, but TG is the best discriminator of GDM from the GTT- group, and it is the only test significantly related to birth-weight ratio--and to glucose intolerance besides glucose itself. The TG association with birth weight is not explained fully by maternal weight. The results suggest that plasma TG may be a physiological contributor to infant birth weight. Further evaluation of plasma TG in GDM screening is justified, but GHb, GPro, and IRI appear to hold less promise.

Metabolism of very-low-density lipoprotein triglyceride by human placental cells: the role of lipoprotein lipase

Several studies have shown lipoprotein lipase (LPL) activity in human placenta, but the quantitative significance and cellular specificity of LPL in this organ are unknown. The objective of this report is to investigate the metabolism of very-low-density lipoprotein triglycerides (VLDL-TG) by the placenta, the role of LPL in this process, and the types of cells involved. Placental cells were obtained by enzymatic digestion (collagenase, hyaluronidase, and DNA-ase) and separated on a 40% Percoll gradient. The trophoblasts were the predominant cell type (80% to 85% pure) isolated at d = 1.033 to 1.048 and macrophages were predominant at d = 1.077 to 1.100 (greater than 95% pure), as characterized by eight immunocytochemical assays using cell protein-specific monoclonal antibodies. Macrophages represented 50% to 60% of cells isolated, and trophoblasts, 40% to 50%. LPL activity was assessed by VLDL-TG hydrolysis in primary 3- to 4-day tissue culture. In a representative experiment, LPL activity (nmol fatty acids (FA)/mg protein/24 h) was 101.3 +/- 5.3 in macrophages and 29.9 +/- 6.5 in the predominant trophoblast cell types, with approximately 20% of these amounts incorporated and reesterified. VLDL-TG hydrolysis and cell lipid uptake in both placental cell types was essentially abolished by a monoclonal anti-LPL antibody. When compared with a model of hepatocytes (Hep G2 cells), the hydrolysis of VLDL-TG was almost undetectable in these cells. In contrast, free fatty acids (FFA) uptake by Hep G2 cells was fourfold to sixfold greater than that by macrophages and trophoblasts, respectively. In conclusion, macrophages and trophoblasts are the two predominant placental cells isolated by enzymatic digestion.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypocaloric diets and ketogenesis in the management of obese gestational diabetic women

The extent to which given levels of caloric restriction will improve glycemic status but increase plasma ketone bodies in gestational diabetic women has received little attention. After reviewing the underlying physiology, we present data on two feeding studies investigating the question. In the first, a weight-maintaining approximately 2400-kcal/day diet was fed on a metabolic ward to 12 gestational diabetic women for 1 week. In the second week, subjects were randomized to a continuation of the 2400-kcal/day diet or to a 1200-kcal/day diet. Twenty-four-hour mean glucose levels remained unchanged in the control group but declined in the calorie-restricted group (6.7 mM or 121 mg/dl in week 1 vs 5.4 mM or 97.3 mg/dl in week 2) (p less than 0.01). Nine-hour overnight fasting plasma insulin also declined but oral glucose tolerance did not improve with caloric restriction. Fasting plasma beta-hydroxybutyrate rose in the calorie-restricted group, along with an increase in ketonuria, but not in the control group. A second study compared the impact of a 33% calorie-restricted diet or insulin to a full-calorie diet in a similar 2-week experimental design and measured hepatic glucose output and insulin sensitivity with dideuterated glucose before and during an insulin clamp. Diet in three subjects improved fasting and 24-hr mean glucose by 22 and 10%, respectively, whereas prophylactic insulin in three subjects produced 0 and 4% reductions, respectively. On average, ketonuria after a 9-hr fast declined to an equivalent degree with both treatments. Hepatic glucose output and insulin sensitivity were not statistically significantly altered by gestational diabetes or the therapeutic interventions compared to nondiabetic normal weight or obese pregnant controls. In conclusion, 50% caloric restriction improves glycemic status in obese women with gestational diabetes but is associated with an increase in ketonuria, which is of uncertain significance. An intermediate 33% level of caloric restriction (to 1600-1800 kcal daily) may be more appropriate in dietary management of obese woman with gestational diabetes mellitus and more effective than prophylactic insulin. Further studies are required to confirm these findings.

Intermediary metabolism in pregnancy. First theme of the Freinkel era

During the first half of gestation in the rat, maternal net body weight increases rapidly, whereas in the second half of gestation, the mass of maternal structures declines, coincident with the rate of maternal fat accumulation. Enhanced maternal food intake, extrahepatic tissue lipoprotein lipase (LPL) activity, and adipose tissue lipogenesis are responsible for the progressive accumulation of maternal fat. However, during late gestation, decreased fat synthesis in maternal adipose tissue, enhanced lipolytic activity, and decreased LPL activity deplete maternal fat depots. These changes, plus enhanced endogenous production of triglyceride-rich lipoproteins, are also responsible for maternal hypertriglyceridemia. This condition benefits the offspring in two ways: 1) enhanced LPL activity in maternal liver when fasting increases triglyceride consumption for ketone body synthesis, giving the basis for accelerated starvation; and 2) induction of LPL activity in the mammary gland before parturition diverts maternal circulating triglycerides to milk synthesis in preparation for lactation. The magnitude of the maternal-fetal glucose transfer was higher than that of any of the other substrates studied, including alanine, and despite actions to spare glucose, this transfer causes maternal hypoglycemia, which is especially intense in the fasting condition. This increases sympathoadrenal activity in the mother, which may contribute to her active gluconeogenesis. Glycerol was a more efficient glucose precursor than alanine and pyruvate, and whereas glycerol placental transfer is very small, it is proposed that the fetus benefits from this product of adipose tissue lipolysis when it is previously converted into glucose.(ABSTRACT TRUNCATED AT 250 WORDS)

Maternal hypothyroidism during the first half of gestation compromises normal catabolic adaptations of late gestation in the rat

Female rats were mated and thyroidectomized on the same day. Some animals were kept without treatment and killed on day 12 or 21 of gestation (T). Others were subsequently treated daily with 1.8 micrograms L-T4/100 g BW for either the first 12 days and then not treated from that time until day 21 [T+T4(I+0)] or else not treated for the first 12 days and then treated from days 12-21 [T+T4(0+II)]. A final group received treatment during the entire 21-day study [T+T4(I+II)] and was used as the control. The net maternal body weight increased until day 12 of gestation in T+T4(I+II) rats, but not in T animals. On day 21 net maternal body weight was significantly lower in T and T+T4(0+II) than in T+T4(I+II) rats. Lipoprotein lipase activity in the lumbar fat pads increased from days 0 to 12 of gestation and decreased on day 21, whereas in the heart the change was in the opposite direction, and these changes were greater in T+T4(I+II) rats than in T rats. Incorporation of [U-14C]glucose administered in vivo into liver [14C]fatty acids or [14C]glycogen was significantly lower in T rats than in T+T4(I+II) on either the 12th or 21st day of gestation. The response of plasma triglyceride, glycerol, or beta-hydroxybutyrate levels to 24 h of starvation was similar in 12-day pregnant rats regardless of whether they were treated with T4, whereas on day 21 the change was greater in T+T4(I+II) or T+T4(I+0) animals than in T or T+T4(0+II) animals. Results show that maternal hypothyroidism during the first half of gestation impaired the anabolic events occurring during this phase and compromised the normal catabolic response during late gestation even when T4 treatment was restored. However, once maternal metabolic stores were built up normally during the first half of gestation, maternal hypothyroidism during late gestation did not affect the mother's normal metabolic adaptation, including the accelerated response to starvation.

Mechanism of the HDL2 stimulation of progesterone secretion in cultured placental trophoblast

Lipoprotein cholesterol (C) supports the high rate of progesterone production by the human placenta as endogenous cholesterol synthesis is low. To study underlying mechanisms whereby lipoproteins, including high density lipoprotein-2 (HDL2), stimulate progesterone secretion, trophoblast cells were isolated from human term placentas and maintained in primary tissue culture. Lipoproteins were added at several concentrations and medium progesterone secretion was determined. HDL2 (d 1.063-1.125 g/ml) as well as low density lipoproteins (LDL) (d 1.019-1.063 g/ml) but not HDL3 (d 1.125-1.21 g/ml) stimulated progesterone secretion in a dose-dependent manner, with HDL2 cholesterol entering the cell and serving as substrate for progesterone synthesis. Conversely, LDL and HDL2 produced a significant decrease in [2-14C]acetate incorporation into cell cholesterol. Cholesterol-depleted lipoproteins did not stimulate progesterone secretion. The stimulating effect of LDL was abolished by apolipoprotein modification by cyclohexanedione or reductive methylation and by the addition of anti-LDL receptor antibody or 10 microM chloroquine to the medium. [14C]acetate conversion into cholesterol was accelerated by these procedures. However, HDL2 stimulation of progesterone secretion and reduction of [14C]acetate incorporation into cholesterol was not blocked by chemical modification of apolipoproteins, anti-LDL receptor antibody, or chloroquine. Treatment of HDL2 with tetranitromethane or dimethylsuberimidate also did not block the stimulation of progesterone. To determine whether the capacity of HDL2 to deliver cholesterol to the trophoblast cells was restricted to subfractions differing in apoE content, HDL2 was chromatographed on heparin-Sepharose and three fractions (A, B, and C) were obtained. Fraction A was poorest in apoE and free cholesterol, fraction B contained the majority of cholesterol, and fraction C was the richest in apoE and free cholesterol. When added to trophoblast cells, fraction A stimulated little progesterone secretion, fraction B stimulated moderately, and fraction C did so greatly. Modification of these subfractions with cyclohexanedione or reductive methylation did not inhibit these effects. In conclusion, HDL2 stimulated progesterone secretion in human trophoblast cell culture. Contrary to LDL, the HDL effect was not mediated by apolipoproteins or the LDL receptor pathway. The ability of HDL2 to stimulate progesterone secretion is consistent with the passive transfer of free cholesterol to the cell membrane from a physicochemically specific subfraction of HDL. This mechanism may be an auxiliary source of cholesterol for human steroidogenic cells.

Different response to maternal hypothyroidism during the first and second half of gestation in the rat

Female rats were mated and thyroidectomized (T) on the same day and divided into four groups. Three groups were subsequently treated daily with 1.8 micrograms L-T4/100 g body wt: 1) for the first 12 days [T + T4 (I)]; 2) from the 12th day until death [T + T4 (II)]; or 3) for the entire 21-day study [T + T4 (I + II)]. The other T animals were maintained without treatment. (T), and another group of mated rats were sham operated (C). Maternal body weight increase during gestation did not differ between T + T4 (I + II) and C dams, whereas it was smaller in T dams from the 7th gestational day onward. Neither interruption of T4 treatment in the T + T4 (I) rats after the 12th day nor treatment initiated at that time in the T + T4 (II) group modified their body weights. At day 21, the weights of the maternal conceptus-free body and liver, the placenta, and the fetuses were lower in the T and T + T4 (II) animals than in either the C and the T + T4 (I + II) animals. Maternal plasma T4 and pituitary GH content were reduced, and plasma TSH was enhanced in both T and T + T4 (I) dams. In fetuses, plasma TSH concentration was augmented in T and T + T4 (I) rats and unchanged in T + T4 (II) animals when compared with those of T + T4 (I + II). Pituitary GH content was reduced in T and T + T4 (II) fetuses and unchanged in the T + T4 (I) group. We propose that maternal thyroidectomy greatly decreases the thyroid hormone levels in embryonic structures during the first half of gestation and inhibits normal maternal metabolic changes during this period. In addition to interfering with normal fetal development, these effects reduce the quantity of maternal substrates available to fetuses during the last phase of gestation. In contrast, when maternal hypothyroidism occurs during the second half of gestation, the effects are not as detrimental because fetal thyroid gland activity is adequate, and maternal catabolic adaptations are not impaired.

Postnatal development of brain TRH, serum TSH and thyroid hormones in the male and female rat

The postnatal development of immunoreactive TRH in the central nervous system (CNS), serum TSH and thyroid hormones was studied in both male and female normal rats. While in most structures of the CNS, TRH increased until day 20-30, serum TSH values peaked at day 15 as did T4. Significant differences were also obtained between both sexes in these parameters. These data further support the fact that pituitary-thyroid axis maturation is independent of brain TRH.