Early Levothyroxine Treatment for Subclinical Hypothyroidism or Hypothyroxinemia in Pregnancy: The St Carlos Gestational and Thyroid Protocol

The optimal maternal levels of thyroid hormones (TH) during the first trimester of gestation have not been established, nor has the ideal moment to initiate levothyroxine treatment (LT) to improve the evolution of gestation and fetal development. Cut-off points for Thyroid-stimulating hormone (TSH) <2.5 µIU/mL and free thyroxine (FT4)>7.5 pg/mL have been recommended. There are no data on whether initiation of LT <9th Gestational Week (GW) can have a favourable impact.

OBJECTIVE

To define the TSH/FT4 percentiles corresponding with 2.5 µIU/mL and 7.5 pg/mL levels, respectively, at GW8 (Study 1), and evaluate the effects of protocol-based LT before GW9 on gestation evolution, in women with TSH ≥2.5 µIU/mL and/or FT4≤ 7.5 pg/mL (study 2).

SUBJECTS

2768 consecutive pregnant women attending the first gestational visit from 2013-2014 and 3026 from 2015-2016 were eligible for Study I and 2 respectively. A final 2043 (study 1) and 2069 (study 2) women were assessed in these studies.

RESULTS

Study 1: The FT4 level of 7.5 pg/mL corresponds with the 17.9th percentile, a TSH level of 2.5 µIU/mL with the 75.8^th. Women with TSH ≥2.5 µIU/mL had a history of fetal losses more frequently than those <2.5 (OR 2.33 (95%CI): 1.58-3.12), as did those with FT4 ≤7.5 pg/ml compared to those >7.5 (OR 4.81; 3.25-8.89). Study 2: A total of 1259 women had optimal TSH/FT4 levels (Group 1), 672 (32.4%, Group 2) had suboptimal TSH or T4l, and 138 (6.7%, Group 3) had suboptimal values of both. 393 (58.5%) in Group 2 and 88 (63.8%) in Group 3 started LT before GW9. Mean (SD) GW24 levels were TSH: 1.96 ± 1.22 µIU/mL and FT4: 7.07 ± 1.25 pg/mL. The highest FT4 value was 12.84 pg/mL. The adjusted risk for an adverse event if LT was started early was 0.71 (0.43-0.91) for Group 2 and 0.80 (0.66-0.94) for Group 3.

CONCLUSIONS

Early LT in women with suboptimum levels of TSH/FT4 (≥2.5µIU/mL/≤7.5 pg/ml) at or before GW9 is safe and improves gestation progression. These data support the recommendation to adopt these cut-off points for LT initiation, which should be started as early as possible.

Benefits of Adhering to a Mediterranean Diet Supplemented with Extra Virgin Olive Oil and Pistachios in Pregnancy on the Health of Offspring at 2 Years of Age. Results of the San Carlos Gestational Diabetes Mellitus Prevention Study

The intrauterine environment may be related to the future development of chronic diseases in the offspring. The St. Carlos gestational diabetes mellitus (GDM) prevention study, is a randomized controlled trial that evaluated the influence of the early (before 12th gestational week) Mediterranean diet (MedDiet) on the onset of GDM and adverse gestational outcomes. Out of 874 women assessed after delivery (440 control group (CG)/434 intervention group (IG)), 703 children were followed (365/338; CG/IG), with the aim to assess whether the adherence to a MedDiet during pregnancy induces health benefits for the offspring during the first two years of life. Logistic regression analysis showed that the IG in children of mothers with pre-gestational body mass index (BMI) < 25 kg/m² and normal glucose tolerance (NGT), was associated with a lower risk (RR(95% CI)) of suffering from severe events requiring hospitalization due to bronchiolitis/asthma (0.75(0.58–0.98) and 0.77(0.59–0.99), respectively) or other diseases that required either antibiotic (0.80(0.65–0.98) and 0.80(0.65–0.99), respectively), corticosteroid treatment (0.73(0.59–0.90) and 0.79(0.62–1.00) respectively) or both (all p < 0.05). A nutritional intervention based on the MedDiet during pregnancy is associated with a reduction in offspring’s hospital admissions, especially in women with pre-gestational BMI < 25 kg/m² and NGT.

An Early, Universal Mediterranean Diet-Based Intervention in Pregnancy Reduces Cardiovascular Risk Factors in the "Fourth Trimester"

An early antenatal dietary intervention could play an important role in the prevention of metabolic diseases postpartum. The aim of this study is to evaluate whether an early, specific dietary intervention reduces women’s cardiovascular risk in the “fourth trimester”. This prospective cohort study compares 1675 women from the standard-care group (ScG/n = 676), who received standard-care dietary guidelines, with the intervention group (IG/n = 999), who received Mediterranean diet (MedDiet)-based dietary guidelines, supplemented with extra-virgin olive oil and nuts. Cardiovascular risk was determined by the presence of metabolic syndrome (MetS) and insulin resistance syndrome (IrS) (HOMA-IR 3.5) at 12–14 weeks postpartum. MetS was less frequent in the IG (11.3 vs. 19.3%, p < 0.05). The intervention was associated with a reduction in the relative risk of having MetS: 0.74 (95% CI, 0.60–0.90), but not in the risk of IrS. When analyzing the presence of having one or more components of the MetS, the IG had significantly higher rates of having 0 components and lower rates of having ≥1 (p-trend = 0.029). An early MedDiet-based nutritional intervention in pregnancy is associated with reductions in postpartum rates of MetS.

A Mediterranean Diet with an Enhanced Consumption of Extra Virgin Olive Oil and Pistachios Improves Pregnancy Outcomes in Women Without Gestational Diabetes Mellitus: A Sub-Analysis of the St. Carlos Gestational Diabetes Mellitus Prevention Study

AIMS

The aim of the study was to evaluate the effect of a Mediterranean diet (MedDiet), enhanced with extra virgin olive oil (EVOO) and nuts, on a composite of adverse maternofoetal outcomes of women with normoglycemia during pregnancy.

METHODS

This was a sub-analysis of the St Carlos gestational diabetes mellitus Prevention Study. Only normoglycemic women were analysed (697). They were randomized (at 8-12th gestational weeks) to: standard-care control group (337), where fat consumption was limited to 30% of total caloric intake; or intervention group (360), where a MedDiet, enhanced with EVOO and pistachios (40-42% fats of total caloric intake) was recommended. The primary outcome was a composite of maternofoetal outcomes (CMFOs): at least having 1 event of emergency C-section, perineal trauma, pregnancy-induced hypertension and preeclampsia, prematurity, large-for-gestational-age and small-for gestational-age.

RESULTS

Crude relative risk showed that the intervention was associated with a significant reduction in the risk of CMFOs (0.48 [0.37-0.63]; p = 0.0001), with a number-needed-to-treat = 5. Risk of urinary tract infections, emergency C-sections, perineal trauma, large-for-gestational-age and small-for gestational age new-borns were also significantly reduced.

CONCLUSION

A MedDiet, enhanced with EVOO and nuts, was associated with a risk reduction of CMFOs in over 50% in normoglycemic pregnant women. Therefore, it might be a potentially adequate diet for pregnant women.

TRIAL REGISTRATION

Identifier ISRCTN84389045. The study was registered on September 27, 2013. Last edited on September 26, 2018.

A Mediterranean diet with additional extra virgin olive oil and pistachios reduces the incidence of gestational diabetes mellitus (GDM): A randomized controlled trial: The St. Carlos GDM prevention study

BACKGROUND

Gestational diabetes mellitus (GDM) prevalence is increasing and becoming a major public health concern. Whether a Mediterranean diet can help prevent GDM in unselected pregnant women has yet to be studied.

METHODS

We conducted a prospective, randomized controlled trial to evaluate the incidence of GDM with two different dietary models. All consecutive normoglycemic (<92 mg/dL) pregnant women at 8-12 gestational weeks (GW) were assigned to Intervention Group (IG, n = 500): MedDiet supplemented with extra virgin olive oil (EVOO) and pistachios; or Control Group (CG, n = 500): standard diet with limited fat intake. Primary outcome was to assess the effect of the intervention on GDM incidence at 24-28 GW. Gestational weight gain (GWG), pregnancy-induced hypertension, caesarean section (CS), preterm delivery, perineal trauma, small and large for gestational age (SGA and LGA) and admissions to neonatal intensive care unit were also assessed. Analysis was by intention-to-treat.

RESULTS

A total of 874 women completed the study (440/434, CG/IG). According to nutritional questionnaires and biomarker analysis, women in the IG had a good adherence to the intervention. 177/874 women were diagnosed with GDM, 103/440 (23.4%) in CG and 74/434(17.1%) in IG, p = 0.012. The crude relative risk (RR) for GDM was 0.73 (95% CI: 0.56-0.95; p = 0.020) IG vs CG and persisted after adjusted multivariable analysis, 0.75(95% CI: 0.57-0.98; p = 0.039). IG had also significantly reduced rates of insulin-treated GDM, prematurity, GWG at 24-28 and 36-38 GW, emergency CS, perineal trauma, and SGA and LGA newborns (all p<0.05).

CONCLUSIONS

An early nutritional intervention with a supplemented MedDiet reduces the incidence of GDM and improves several maternal and neonatal outcomes.

The impact of switching to the one-step method for GDM diagnosis on the rates of postpartum screening attendance and glucose disorder in women with prior GDM. The San Carlos Gestational Study

AIMS

To compare rates of FPG-HbA1C-based postpartum-glucose disorder (PGD) of women with prior gestational diabetes mellitus (GDM) by Carpenter-Coustan criteria (CCc) versus International Association of Diabetes and Pregnancy Study Groups criteria (IADPSGc).

METHODS

1620 women with GDM were divided into CCc group (2007-March 2012, n=915), and IADPSGc group (April 2012-2013, n=705). Pregravid (PG) body weight (BW) and body mass index (BMI) and postdelivery (PD) BW, BMI, waist circumference (WC), HOMA-insulin resistance (HOMA-IR), HbA1c, glucose and lipid profile were analysed. PGD definition: HbA1c ≥5.7% and/or FPG ≥5.6mmol/l.

RESULTS

Postpartum screening attendance rates (PSAr) were similar in both groups, CCc: 791 (86.5%) and IADPSGc: 570 (81%) as in PGD rates (PGDr), CCc: 233 (29.5%) and IADPSGc: 184 (32.3%). Both cohorts had similar PG-BMI, WC and PD-BMI. Both CCc and IADPSGc women had a significantly higher probability of having PGD when PG-BMI ≥25Kg/m(2) (CCc: OR: 1.55; IC 95% 1.06-2.26; p=0.016), (IADPSGc: OR: 1.42; IC 95% 1.03-2.38; p=0.046) as well as when WC ≥89.5cm, and age ≥34years, and in CCc women when PD-WG >0Kg, all adjusted by ethnicity and parity.

CONCLUSIONS

Changing GDM diagnostic methodology did not affect PSAr and PGDr, in spite of screening more women. Thus, using IADPSGc allowed the identification of a larger number of women with PGD.

Gestational diabetes mellitus treatment reduces obesity-induced adverse pregnancy and neonatal outcomes: the St. Carlos gestational study

BACKGROUND

Obesity and gestational diabetes mellitus (GDM) increase the morbidity of the mother and newborn, which could increase further should they coexist. We aimed to determine the risk of adverse pregnancy and neonatal outcomes associated with excess weight (EW), and within this group identify potential differences between those with and without GDM.

METHODS

We carried out a post-hoc analysis of the St. Carlos Gestational Study which included 3312 pregnant women, arranged in 3 groups: normal-weight women (NWw) (2398/72.4%), overweight women (OWw) (649/19.6%) and obese women (OBw) (265/8%). OWw and OBw were grouped as EW women (EWw). We analyzed variables related to adverse pregnancy and neonatal outcomes.

RESULTS

The relative risk (95% CI) for GDM was 1.82 (1.47 to 2.25; p<0.0001) for OWw, and 3.26 (2.45 to 4.35; p<0.0001) in OBw. Univariate analysis showed associations of EW to higher rates of prematurity, birth weight >90th centile, newborns admitted to neonatal intensive care unit (NICU), instrumental delivery and cesarean delivery (all p<0.005). Multivariate analysis, adjusted for parity and ethnicity, showed that EW increased the risk of prematurity, admission to NICU, cesarean and instrumental delivery, especially in EWw without GDM. NWw with GDM had a significantly lower risk of admission to NICU and cesarean delivery, compared with NWw without GDM.

CONCLUSIONS

EW is detrimental for pregnancy and neonatal outcomes, and treatment of GDM contributes to lowering the risk in EWw and NWw. Applying the same lifestyle changes to all pregnant women, independent of their weight or GDM condition, could improve these outcomes.

Lifestyle patterns in early pregnancy linked to gestational diabetes mellitus diagnoses when using IADPSG criteria. The St Carlos gestational study

Early-pregnancy lifestyle (EPL) could influence the development of gestational diabetes mellitus(GDM), depending on the diagnostic criteria used.

OBJECTIVE

We studied EPL in 1750 pregnant women using Carpenter-Coustan criteria(CCc), and in 1526 with the International Association of Diabetes and Pregnancy Study Groups criteria(IADPSGc).

METHODS

GDM risk factors were assessed in women between 24 and 28 weeks of gestational age during two consecutive years. A semiquantitative frequent-food-consumption questionnaire was used to evaluate lifestyle during pregnancy. Multiple logistic regression analysis was conducted to assess GDM risk with different lifestyle patterns.

RESULTS

Using IADPSGc, the GDM ORs (95%CI) for intake/week were: nuts >3 times: 0.59 (0.39-0.91; p < 0.015), refined cereals ≤1 serving: 0.72(0.58-0.89; p < 0.003), juices <4 servings: 0.77 (0.62-0.95; p < 0.017), cookies and pastries <4 servings: 0.71(0.57-0.89; p < 0.003) as compared to opposite habits. No significant nutritional patterns were found to be significant using CCc. The OR (95%CI) for GDM with none of the four risk patterns as compared to having three-four risk factors was 0.21(0.07-0.62; p < 0.005), remaining significant after stratification by BMI, age, obstetric events, parity and family history. The multiple logistic regression model including nutritional categories and pregestational BMI, age, obstetric history, parity, personal/family history, had an area under the curve(AUC) of the receiver operating curve(ROC) for the probability to predict GDM of 0.66 (CI 95%: 0.63-0.69; p < 0.001).

CONCLUSION

Our study is the first to identify four early-pregnancy nutritional patterns associated with the GDM when using IADPSGc. Adherence to a low-risk nutritional pattern from early pregnancy on could be an effective strategy for GDM prevention.

Introduction of IADPSG criteria for the screening and diagnosis of gestational diabetes mellitus results in improved pregnancy outcomes at a lower cost in a large cohort of pregnant women: the St. Carlos Gestational Diabetes Study

OBJECTIVE

The use of the new International Association of the Diabetes and Pregnancy Study Groups criteria (IADPSGC) for the diagnosis of gestational diabetes mellitus (GDM) results in an increased prevalence of GDM. Whether their introduction improves pregnancy outcomes has yet to be established. We sought to evaluate the cost-effectiveness of one-step IADPSGC for screening and diagnosis of GDM compared with traditional two-step Carpenter-Coustan (CC) criteria.

RESEARCH DESIGN AND METHODS

GDM risk factors and pregnancy and newborn outcomes were prospectively assessed in 1,750 pregnant women from April 2011 to March 2012 using CC and in 1,526 pregnant women from April 2012 to March 2013 using IADPSGC between 24 and 28 weeks of gestation. Both groups received the same treatment and follow-up regimes.

RESULTS

The use of IADPSGC resulted in an important increase in GDM rate (35.5% vs. 10.6%) and an improvement in pregnancy outcomes, with a decrease in the rate of gestational hypertension (4.1 to 3.5%: -14.6%, P < 0.021), prematurity (6.4 to 5.7%: -10.9%, P < 0.039), cesarean section (25.4 to 19.7%: -23.9%, P < 0.002), small for gestational age (7.7 to 7.1%: -6.5%, P < 0.042), large for gestational age (4.6 to 3.7%: -20%, P < 0.004), Apgar 1-min score <7 (3.8 to 3.5%: -9%, P < 0.015), and admission to neonatal intensive care unit (8.2 to 6.2%: -24.4%, P < 0.001). Estimated cost savings was of €14,358.06 per 100 women evaluated using IADPSGC versus the group diagnosed using CC.

CONCLUSIONS

The application of the new IADPSGC was associated with a 3.5-fold increase in GDM prevalence in our study population, as well as significant improvements in pregnancy outcomes, and was cost-effective. Our results support their adoption.

Early management of type 2 diabetes based on a SMBG strategy: the way to diabetes regression--the St Carlos study : a 3-year, prospective, randomized, clinic-based, interventional study with parallel groups

The aims are to define the regression rate in newly diagnosed type 2 diabetes after lifestyle intervention and pharmacological therapy based on a SMBG (self-monitoring of blood glucose) strategy in routine practice as compared to standard HbA1c-based treatment and to assess whether a supervised exercise program has additional effects. St Carlos study is a 3-year, prospective, randomized, clinic-based, interventional study with three parallel groups. Hundred and ninety-five patients were randomized to the SMBG intervention group [I group; n = 130; Ia: SMBG (n = 65) and Ib: SMBG + supervised exercise (n = 65)] and to the HbA1c control group (C group) (n = 65). The primary outcome was to estimate the regression rate of type 2 diabetes (HbA1c <6 % on metformin treatment). After 3 years of follow-up, diabetes regression was achieved by 56 patients, 6 (9.2 %) from the C group, 21 (32.3 %) from the Ia group and 29 (44.6 %) from the Ib group. RR (95 % CI) for diabetes regression in the intervention group (Ia + Ib) was 4.5 (2.1-9); p < 0.001 and remained after stratification by gender, age and BMI. This difference was associated with healthier changes in lifestyle and greater weight loss. RR for a weight loss >4 kg was 3.6 (1.8-7); p < 0.001. This study shows that the use of SMBG in an educational program effectively increases the regression rate in newly diagnosed type 2 diabetic patients after 3 years of follow-up. These data suggest that SMBG-based programs should be extended to primary care settings where diabetic patients are usually attended.

Prevalence of the metabolic syndrome in Spain using regional cutoff points for waist circumference: the di@bet.es study

The aim of the study is to assess the prevalence of metabolic syndrome (MetS) in Spain using specific cutoff points for waist circumference (WC) (>94.5 cm for men and >89.5 cm for women) and evaluating the influence of several socio-demographic and economic factors. Data on MetS were obtained from a national study of 4,727 subjects from 18 to 90 years of age, conducted in Spain between 2009 and 2010 (The di@bet.es study). MetS was defined applying the new Harmonized definition (evaluating the use of abdominal obesity (AO) as a obligatory criterion for MetS or not) as well as with other widely used criteria. Results were then compared with data from previous studies. Multiple logistic regression models were used to evaluate the influence of different social factors. The age-standardized MetS prevalence was 38.37 % (CI 35.74-40.99) in men and 29.62 % (CI 27.56-31.69) in women, when AO was required as a diagnostic criterion; 42.13 % (CI 39.37-44.89) and 32.31 % (CI 30.15-34.47) in men and women, respectively, if AO was not considered mandatory. Prevalence of MetS increased with age (p < 0.001 for trend). Women with a lower educational level were more likely to have MetS (OR 4.4; 95 % CI: 2.84-6.7) as compared with those with a higher educational level. Subjects with MetS had a worse physical quality of life. The combination of AO, hypertension and carbohydrate alterations was the most common MetS' pattern. A high prevalence of MetS was detected in the Spanish population especially in men, the elderly and women with a low educational level.

Association of low serum 25-hydroxyvitamin D levels in pregnancy with glucose homeostasis and obstetric and newborn outcomes

OBJECTIVE

To evaluate the association of maternal serum 25-hydroxyvitamin D (25[OH]D) status with glucose homeostasis and obstetric and newborn outcomes in women screened for gestational diabetes mellitus (GDM).

METHODS

Consecutive women were screened for GDM at 24 to 28 weeks' gestation during the months of maximal sunlight exposure in Spain (June through September). Serum 25(OH)D levels and parameters of glucose homeostasis were measured. Outcomes of the delivery and newborn were collected.

RESULTS

Two hundred sixty-six women were screened. Vitamin D deficiency (25[OH]D <20 ng/mL) was observed in 157 women (59%). We observed an inverse correlation between 25(OH)D levels and hemoglobin A1c, homeostasis model assessment of insulin resistance, serum insulin, and fasting and 1-hour oral glucose tolerance test glucose levels (P<.001). With a 25(OH)D concentration less than 20 ng/mL, the odds ratios were 3.31 for premature birth (95% confidence interval, 1.52-7.19; P<.002) and 3.93 for cesarean delivery (95% confidence interval, 2.00-7.73; P<.001). A 25(OH)D concentration of 20 ng/mL had 79% sensitivity and 51% specificity for cesarean delivery and 80% sensitivity and 45% specificity for premature birth. The cutoffs with the best combination of sensitivity and specificity were 16 ng/mL for cesarean delivery (62.9% sensitivity and 61.2% specificity) and 14 ng/mL for premature birth (66.7% sensitivity and 71.0% specificity).

CONCLUSIONS

In the population we sampled, vitamin D deficiency is very common during pregnancy. Lower 25(OH)D levels are associated with disorders of glucose homeostasis and adverse obstetric and newborn outcomes.

Effect of lifestyle on the risk of gestational diabetes and obstetric outcomes in immigrant Hispanic women living in Spain

BACKGROUND

Data about the immigrant population living in Spain, their lifestyle habits, and risk factors for gestational diabetes mellitus (GDM) are limited. Thus, the aim of the present study was to describe risk factors for the onset of GDM, the evolution of gestation and delivery, and newborns of Hispanic women living in Spain compared with those of Spanish women.

METHODS

A semiquantitative questionnaire regarding lifestyle habits was administered to 459 pregnant women (115 Hispanic) with a positive O'Sullivan test (24-28 weeks gestation) between 1 April 2007 and 31 March 2008. Information was collected regarding gestation, delivery, and the newborn.

RESULTS

The prevalence of GDM increased with mother's age, pregestational overweight/obesity, and multiparity. In addition, GDM was associated with lower pregestational fiber and a lower intake of low glycaemic index foods in Hispanic women. The odds ratios (OR) for the total population were 2.53 (95% confidence interval [CI] 1.28-5.01) for overweight, 3.68 (95% CI 1.72-7.90) for obesity, 3.83 (95% 2.03-7.23) for age ≥35 years, and 1.64 (95% CI 1.02-3.01) for multiparity. Newborns from the Hispanic population were significantly heavier than newborns from Spanish women and the rate of Caesarean delivery was significantly higher in the Hispanic population with GDM compared with those without GDM.

CONCLUSIONS

The immigrant Hispanic population living in Spain trends to acquire the same risk factors associated with lifestyle to the indigenous population. Preventive strategies must stress increased physical activity and fiber intake, decreased intake of sweetened beverages, and an effective reduction in body weight before pregnancy.

Dp71ab/DAPs complex composition changes during the differentiation process in PC12 cells

PC12 cells express different Dp71 isoforms originated from alternative splicing; one of them, Dp71ab lacks exons 71 and 78. To gain insight into the function of Dp71 isoforms we identified dystrophin associated proteins (DAPs) that associate in vivo with Dp71ab during nerve growth factor (NGF) induced differentiation of PC12 cells. DAPs expression was analyzed by RT-PCR, Western blot and indirect immunofluorescence, showing the presence of each mRNA and protein corresponding to alpha-, beta-, gamma-, delta-, and epsilon-sarcoglycans as well as zeta-sarcoglycan mRNA. Western blot analysis also revealed the expression of beta-dystroglycan, alpha1-syntrophin, alpha1-, and beta-dystrobrevins. We have established that Dp71ab forms a complex with beta-dystroglycan, alpha1-syntrophin, beta-dystrobrevin, and alpha-, beta- and gamma-sarcoglycans in undifferentiated PC12 cells. In differentiated PC12 cells, the complex composition changes since Dp71ab associates only with beta-dystroglycan, alpha1-syntrophin, beta-dystrobrevin, and delta-sarcoglycan. Interestingly, neuronal nitric oxide synthase associates with the Dp71ab/DAPs complex during NGF treatment, raising the possibility that Dp71ab may be involved in signal transduction events during neuronal differentiation.

Differential expression and subcellular distribution of dystrophin Dp71 isoforms during differentiation process

Dp71 is the major product of the Duchenne muscular dystrophy gene in the brain. In order to study the function of Dp71 in the nervous system we examined the expression of Dp71 isoforms in PC12 rat pheochromocytoma cell line, a well-established system to study neuronal differentiation. We show by reverse transcriptase-polymerase chain reaction and Western blot assays that PC12 cells express two Dp71 isoforms. One isoform lacks exon 71 and the other isoform lacks exons 71 and 78 (Dp71d and Dp71f isoforms respectively). Nerve growth factor-induced neuronal differentiation of PC12 cells results in differential regulation of the expression and subcellular localization of Dp71 isoforms: a) the amount of Dp71f protein increases nine-fold in total extracts while Dp71d increases up to seven-fold in nuclear extracts; b) Dp71f relocates from the cytoplasm to neuritic processes, being prominent at varicosities and the growth cone; c) Dp71d relocates almost entirely to the nucleus and is detected to a lower extent in the cytoplasm and neuritic processes. Dp71f co-localizes with beta-dystroglycan and synaptophysin while Dp71d co-localizes with beta-dystroglycan in the nucleus. Dp71d accumulates at cell-cell contacts where Dp71f is absent. These results suggest that Dp71d and Dp71f associate with different subcellular complexes and therefore may have distinct functions in PC12 cells.

Myotonic dystrophy protein kinase (DMPK) gene expression in lymphocytes of patients with myotonic dystrophy

BACKGROUND

Myotonic dystrophy (DM) is an autosomal dominant neuromuscular disorder with defects in many tissues, including skeletal muscle myotonia, progressive myopathy, and abnormalities in heart, brain, and endocrine systems. It is associated with a trinucleotide repeat occurring in the 3' (UTR) untranslated region of the myotonic dystrophy protein kinase (DMPK) gene. Several studies have been carried out to determine DMPK gene expression in muscle and non-muscle tissues.

METHODS

DMPK gene expression was determined in lymphocytes of adult-onset patients with DM and normal controls. To quantitate total locus expression as well as allele-specific mRNA levels, semiquantitative RT-PCR assay was used. Allele-specific expression was analyzed using a Bpm1 polymorphism located at exon 10 of the DMPK gene.

RESULTS

In heterozygous patients with DM, we observed a fourfold difference between mRNA levels produced by the Bpm1-undigested allele (187 bp) compared to the Bpm1-digested allele (136 bp). By using (CTG) trinucleotide (with cytosine, thymine, and guanine) expansion polymorphism, it was shown that the down-regulated allele corresponds to the mutant allele. Interestingly, the reduction in the mutant allele-transcript levels is compensated by an increase of the wild-type allele, yielding no significant differences in total locus mRNA amount between patients and normal individuals.

CONCLUSIONS

These results suggest that the expression of the two alleles at the DMPK locus in lymphocytes is coordinated. The reduction in mutant-allele transcript levels is compensated by an increase in wild-type allele mRNA levels.

Alternative splicing regulates the nuclear or cytoplasmic localization of dystrophin Dp71

The subcellular distribution of Dp71 isoforms alternatively spliced for exon 71 and/or 78 was examined. The cDNA sequence of each variant was fused to the C-terminus of the green fluorescent protein and the constructs were transfected transiently in the cell lines HeLa, C2C12 and N1E-115. The subcellular distribution of the fused proteins was determined by confocal microscope analysis. The Dp71 isoform lacking the amino acids encoded by exons 71 and 78 was found exclusively in the cytoplasm whereas the variants containing the amino acids encoded by exon 71 and/or exon 78 show a predominant nuclear localization. The nuclear localization of Dp71 provides a new clue towards the establishment of its cellular function.

Expression and localization of utrophin in differentiating PC12 cells

To ascertain the role of utrophin in cultured neuronal cells, we investigated its expression and distribution along the NGF-induced differentiation of PC12 cells grown on different substrata. Utrophin mRNA was measured by RT-PCR assay and utrophin protein was quantified by immunoblot analysis. The distribution of utrophin and beta-dystroglycan was analyzed by confocal microscopy. We demonstrate that utrophin protein was increased 4-fold during differentiation of cells grown laminin. Concomitant with this up-regulation, utrophin was enriched at the growth cones in differentiating cells, where it co-localizes with beta-dystroglycan. These data suggest the presence of a utrophin-beta-dystroglycan complex in PC12 cells that participates in the formation and/or stabilization of the growth cone-extracellular matrix adhesion.

A 24-kDa cloned zinc metalloprotease from Actinobacillus pleuropneumoniae is common to all serotypes and cleaves actin in vitro

Actinobacillus pleuropneumoniae causes pleuropneumonia in swine. This bacterium secretes proteases that degrade porcine hemoglobin and IgA in vitro. To further characterize A. pleuropneumoniae proteases, we constructed a genomic library expressed in Escherichia coli DH5alpha, and selected a clone that showed proteolytic activity. The recombinant plasmid carries an 800-base pair A. pleuropneumoniae gene sequence that.codes for a 24-kDa polypeptide. A 350-base pair PstI fragment from the sequence hybridized at high stringency with DNA from 12 serotypes of A. pleuropneumoniae, but not with DNA from Actinobacillus suis, Haemophilus parasuis, Pasteurella haemolytica, Pasteurella multocida A or D, or E. coli DH5alpha, thus showing specificity for A. pleuropneumoniae. The expressed polypeptide was recognized as an antigen by convalescent-phase pig sera. Furthermore, a polyclonal antiserum developed against the purified polypeptide recognized an A. pleuropneumoniae oligomeric protein in both crude-extract and cell-free culture media. This recombinant polypeptide cleaved azocoll, gelatin, and actin. Inhibition of the proteolytic activity by diethylpyrocarbonate suggests that this polypeptide is a zinc metalloprotease.

Sp1 and AP2 transcription factors are required for the human fragile mental retardation promoter activity in SK-N-SH neuronal cells

The promoter of the human fragile mental retardation gene (FMR1) was functionally analyzed in order to identify elements responsible for its regulation. Plasmids carrying the wild type or different deleted-promoter sequences driving the chloramphenicol acetyl transferase gene (CAT) were transiently transfected into the SK-N-SH cells and the CAT activity was assessed. Deletion studies suggested that major regulatory elements are present in a DNA region between positions -123 and -51. Gel mobility shift and footprinting assays using a DNA fragment encompassing that promoter region showed that SP1 and AP2 transcription factors could be involved in the functioning of the FMR1 promoter.

Nus A is involved in transcriptional termination on lambda tI

The transcriptional terminator tI generates the 3'end of the integrase (int) gene transcript that is read from the lambda PI promoter in lambda phage. We have studied the factors that affect transcription termination in vitro and in vivo at the lambda tI terminator. In vitro transcriptional studies showed that tI is about 80% efficient in the presence of purified NusA protein, whereas it is only about 50% efficient in its absence. In vivo studies, where the readthrough transcript of lambda tI was measured by quantitative dot blot analysis, gave about 80% efficiency in wild-type strains, but only 60% in the nusA1 mutant strain at non-permissive temperatures. These results support the idea that termination at lambda tI in vivo involves interaction with the NusA factor.

A novel mutation in the KH domain of polynucleotide phosphorylase affects autoregulation and mRNA decay in Escherichia coli

Polynucleotide phosphorylase (PNPase) is a key 3'-5' exonuclease for mRNA decay in bacteria. Here, we report the isolation of a novel mutant of Escherichia coli PNPase that affects autogenous control and mRNA decay. We show that the inactivation of PNPase by a transposon insertion increases the half-life of galactokinase mRNA encoded by a plasmid. When the bacteriophage lambda int gene retroregulator (sib/tI ) is placed between pgal and galK, it severely diminishes galactokinase expression because of transcription termination. The expression of galK from this construct is increased by a single base mutation, sib1, which causes a partial readthrough of transcription at tI. We have used this plasmid system with sib1 to select E. coli mutants that depress galK expression. Genetic and molecular analysis of one such mutant revealed that it contains a mutation in the pnp gene, which encodes the PNPase catalytic subunit alpha. The mutation responsible (pnp-71 ) has substituted a highly conserved glycine residue in the KH domain of PNPase with aspartate. We show that this G-570D substitution causes a higher accumulation of the alpha-subunit as a result of defective autoregulation, thereby increasing the PNPase activity in the cell. The purified mutant alpha-subunit shows the same electrophoretic mobility in denaturing gels as the wild-type subunit, as expected. However, the mutant protein present in crude extracts displays an altered electrophoretic mobility in non-denaturing gels that is indicative of a novel enzyme complex. We present a model for how the pnp-71 mutation might affect autoregulation and mRNA decay based on the postulated role of the KH domain in RNA-protein and protein-protein interactions.

Pattern of deletions of the dystrophin gene in Mexican Duchenne/Becker muscular dystrophy patients: the use of new designed primers for the analysis of the major deletion "hot spot" region

We have analyzed 59 unrelated Mexican Duchenne/Becker muscular dystrophy patients (DMD/BMD) using PCR analysis of the 2 prone deletion regions in the DMD gene. Thirty one (52%) of the patients had a deletion of one or several of the exons. Most of the alterations (87%) were clustered in exons 44-52, this being the highest percentage reported until now. In order to improve the molecular diagnosis in the Mexican population, we designed a new multiplex assay to PCR amplify exons 44-52. This assay allowed for the identification of a greater number of deletions in this region compared with the 9 and 5-plex assays previously described and to determine most of the deletion end boundaries. This is a reliable alternative for the initial screening of the DMD patients in the Mexican population.

Analysis of the (CAG)n repeat causing Huntington's disease in a Mexican population

We investigated the allele distribution of the polymorphic (CAG)n repeat in the IT15 gene in 96 normal subjects from the Mexican population and 83 unrelated patients with Huntington's disease. Our results show that the size distributions of normal and affected alleles do not overlap. Normal alleles range from 13 to 32 triplets, with 18 being the most frequent allele, while HD alleles contain 37 to 76 repeats with 42 being the most frequent. One allele in the range of intermediate alleles was found (32 repeats) in a normal subject. The juvenile onset cases in this study are associated with an expansion greater than 49 repeats. In the available parent-offspring pairs, paternal alleles show instability with an expansion of 28 repeats in one case.

Point mutations in a transcription terminator, lambda tI, that affect both transcription termination and RNA stability

The terminator tI is located approx. 280 nucleotides beyond the int gene of bacteriophage lambda. Besides its role as a transcription terminator, tI may confer stability to the int message by protecting it from 3' exonucleolytic degradation. In order to study the role of the tI sequence in transcription termination and RNA stability, three different point mutations tI1, tI2, and tI3 were isolated and characterized. All the tI mutations map in the G + C-rich region of dyad symmetry in the terminator and decrease the transcriptional termination of tI in vivo from 99% for the wild type terminator to 81-93% as determined by galactokinase activity and in vitro from 80% for the wild type terminator to 8-12% using the E. coli RNA polymerase. Additionally, the tI mutations cause upstream transcript instability in vivo. This instability defect caused by tI mutations is compensated by the host mutant deficient in polynucleotide phosphorylase resulting in increased steady state levels of these mutant transcripts. The results show that the intact hairpin of tI is essential for efficient transcription termination and for maintaining mRNA stability by blocking the 3' to 5' exonucleolytic activity of polynucleotide phosphorylase.

Expression of dystrophin Dp71 during PC12 cell differentiation

The expression of dystrophin-protein 71 (Dp71) was investigated during nerve growth factor (NGF) induced differentiation of PC12 cells. A semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay was designed to measure Dp71 mRNA, whereas the Dp71 protein amount was evaluated by immunoblot analysis using an anti-dystrophin monoclonal antibody. Comparison with control cultures showed that Dp71 mRNA and protein levels increased in parallel with NGF treatment peaking with increments of 60% and 1.4 times, respectively. The upregulation of Dp71 expression during PC12 cells differentiation point at PC12 cells as a suitable model for studying the function of Dp71 in neuronal cells.

[Restoration of transcription antitermination of N- bacteriophages in Escherichia coli with a mutant RNA polymerase]

The N protein of bacteriophage lambda modifies Escherichia coli RNA polymerase in such a way that it transcribes through termination signals, in a process called antitermination. In general N-mutants are not able to perform transcription antitermination. In this paper we report the suppression of N7 and Nmar3 mutations by Escherichia coli ron-lon strain. The lon mutation causes the N protein half-life to raise, suggesting that excess of N7 fragment or Nmar3 protein overcome the defect in antitermination. Under these conditions the lambda N-phages produced a titer similar to lambda wild type, although the plaques were smaller. These observations highlight the relevance of N half life in the regulation of transcription antitermination.

Characterization of two DNA populations of Giardia lamblia

Total DNA was isolated from the parasitic protozoan Giardia lamblia and separated into two distinct populations of different densities by centrifugation through CsCl gradients containing Hoechst dye 33258. The two populations obtained were characterized by restriction enzyme analysis and nucleic acid hybridization. The less-dense population contains non-repetitive DNA and may encode mainly structural genes, such as those for alpha- and beta-tubulin. Digestion of the DNA with several restriction endonucleases showed that the denser band was composed of a 5.5 kb unit which contains the G. lamblia ribosomal RNA cistron in tandem repeated organization.

Electron microscopy and biochemical properties of polyamine-compacted DNA

We have obtained polyamine-compacted DNA and analyzed it by electron microscopy employing the method described by Dubochet, suitable for the study of complexes in which the main interactions are of ionic character. In addition, we have developed a simple biochemical method, based on the action of pancreatic DNase I, to demonstrate the condensation of DNA with spermidine. DNA-spermidine complexes are resistant to the action of DNase I, and there is a strong correlation between the presence of condensed DNA forms, both as toroids and as cylinders, and the insensitivity to DNase I activity. We have also shown that pBR322 DNA-spermidine complexes are transcriptionally active in the presence of Escherichia coli RNA polymerase. This supports the data concerning the biological activity of spermidine-condensed DNA.

Mutations of bacteriophage lambda that define independent but overlapping RNA processing and transcription termination sites

Bacteriophage lambda int gene expression is regulated differentially from transcripts originated at the pL and pI promoters. Transcripts initiated at pI terminate at the site tI and express int gene product efficiently. Polymerases starting at pL do not terminate at tI, due to the antiterminating activity of lambda N protein. The pL transcripts are unable to express Int protein efficiently because sib, a control site overlapping tI in the unterminated RNA, is processed by host RNase III. We have isolated lambda sib- mutants by their inability to inhibit int expression from pL transcripts. sib mutations were genetically mapped to the left of the lambda attachment site, and do not structurally alter this site for recombination. Several sib mutations do alter the nucleotide sequence of the overlapping sib and tI sites. The lambda sib- mutants tested prevent RNA processing but do not affect transcription termination in vivo.

Posttranscriptional control of bacteriophage lambda gene expression from a site distal to the gene

The bacteriophage lambda int gene product, integrase, recombines the phage DNA with the host DNA at specific sites on each to accomplish lysogeny. The int gene is transcribed from two promoters, PL and PI, each regulated positively by lambda proteins. The expression of integrase is also controlled from a site, sib, in the b region of the phage genome. This is a unique regulatory site because it is located distal to the structural gene in relation to the promoters. The expression of int from the PL promoter is inhibited when sib is present. This effect appears to be specific for PL because sib does not cause inhibition of PI-dependent int synthesis. lambda mutants that contain alterations in the site have been isolated. Sequence analyses of the mutations reveal single base changes, spanning 37 base pairs (bp) in the b region, some 240 bp beyond the int gene. Another mutant, hef13, which has a phenotype similar to that of sib, introduces a nucleotide change within the same 37-bp region. The sib and hef mutations cluster within a region of dyad symmetry. Regulation of int synthesis by sib occurs after transcription of the int gene. There is no difference in the rate of PL-promoted int mRNA synthesis in either sib+ or sib- phage infections, yet int mRNA is less stable in the sib+ infection. Because RNase III host mutants are defective in sib regulation, processing of the PL mRNA at sib by this endoribonuclease may cause int mRNA decay and decrease int synthesis.