Oral glucose tolerance testing at 1 h and 2 h: relationship with glucose and cardiometabolic parameters and agreement for pre-diabetes diagnosis in patients with morbid obesity

BACKGROUND

One hour plasma glucose concentration (1hPG) during an oral glucose tolerance test (OGTT) may be an alternative to 2-h plasma glucose concentration (2hPG) in the identification of individuals at increased risk of hyperglycaemia, although its role is not fully understood.

AIM

We aim to investigate the relationship of these measures with other glucose parameters, as well as their relationship with cardiometabolic risk markers and the level of agreement for prediabetes mellitus diagnosis, in a sample of patients with morbid obesity.

METHODS

We retrospectively evaluated 656 patients with morbid obesity without diagnosed diabetes. To define prediabetes with 2hPG, 2022 American Diabetes Association guidelines criteria were used, while for 1hPG, glucose ≥ 155 mg/dL was considered. Cohen's Kappa coefficient was used to assess the agreement between both measures of prediabetes mellitus diagnosis.

RESULTS

A Cohen's Kappa coefficient of 0.405 (p < 0.001) was obtained. The 1hPG were positively correlated with homeostatic model assessment for insulin resistance (HOMA-IR) (ρ = 0.281, p < 0.001), fasting plasma glucose (FPG) (ρ = 0.581, p < 0.001), glycated haemoglobin (Hb1AC) (ρ = 0.347, p < 0.001) and were negatively correlated with homeostatic model assessment for cell-β function (HOMA-β) (ρ = -0.092, p = 0.018). 2hPG were also correlated with the same parameters, except for HOMA-β.

CONCLUSION

A fair agreement between 1 and 2hPG was verified. 1hPG criteria may be a useful indicator of β-cell dysfunction and insulin resistance in patients with morbid obesity without diabetes diagnosis.

Leg stiffness and muscle power vs manometer in sportswomen with symptoms of stress urinary incontinence

BACKGROUND

Pelvic floor muscle training can cure or alleviate stress urinary incontinence. This study aimed to evaluate maximum voluntary contractions of the pelvic floor muscle in sportswomen and verify the association with leg stiffness and muscle power, both maximal and submaximal.

METHODS

The sample consisted of 41 sportswomen between 18 and 42 years of age. Pelvic floor muscle strength was measured by the manometer. The sportswomen were instructed to perform 3 maximum voluntary contractions of the perineum, held for 3 seconds. Maximal and submaximal leg stiffness and muscle power were measured with a force platform, in two conditions: 1st condition was the sub-maximal, double leg hop test, which was performed allowing sportswomen to self-select their preferred frequency and 2nd condition was the maximal double leg hop test, which was performed asking athletes to maximize hop height and minimize contact time on the top of the force platform for 6 consecutive hops.

FINDINGS

Maximal and submaximal leg stiffness values increase with increasing age, weight, height, and body mass index, showing positive and significant (p <0.05) or close correlations. There are strong positive correlations between maximal and submaximal leg stiffness (r = 0.759) and between maximal and submaximal muscle power. Maximum voluntary contractions values decrease with increasing leg stiffness: the correlation is significant with maximal leg stiffness.

INTERPRETATION

Maximum voluntary contractions values decrease with increasing leg stiffness and increase with increasing muscle power values. If the training program aims to increase muscle power, it may also increase maximum voluntary contractions.

Adequate magnesium level as an associated factor of pre-diabetes and diabetes mellitus remission in patients with obesity submitted to bariatric surgery

Bariatric surgery (BS) can lead to remission of type 2 diabetes mellitus (T2DM), however, the evidence on the influence of preoperative serum magnesium levels on this reversal is scarce. To study the influence of preoperative serum magnesium levels on the pre-T2DM and T2DM remission one year after BS. Retrospective study carried out among 1656 patients with obesity who underwent BS in the Centro Hospitalar Universitário São João. T2DM and pre-T2DM remission were defined as being normal glycaemic measures of at least one year's after BS and without pharmacological therapy. To assess the association between preoperative serum magnesium levels and pre- and T2DM remission, logistic regression models, crude and adjusted for sex, age and body mass index were computed. Patients with normoglycaemia presented hypomagnesaemia less often than those patients with pre-T2DM and T2DM (17.0% vs. 21.3% vs. 39.9%) (p < 0.001). One year after BS, 62.9% of patients with pre-T2DM or T2DM before BS showed remission. Adequate magnesium levels were positively associated with T2DM and pre-T2DM remission, one year after BS (OR 1.79; 95% CI 1.34-2.38), independently of sex, age, and body mass index. Adequate preoperative serum magnesium levels showed to be an important clinical parameter for pre-T2DM and T2DM remission.

Unraveling the hepatoprotective effects of blueberries in a hypercaloric diet-induced rat model of prediabetes by metabolomic and transcriptomic approaches

Background

We previously described protective effects of blueberry juice (BJ) against hepatic steatosis evolution in a hypercaloric diet-induced rat model of prediabetes; however, the underlying mechanisms, are still scarcely explored. Herein, we aim to elucidate the molecular pathways underpinning BJ hepatoprotection on the dysmetabolism evolution in a rat model of prediabetes.

Methods

A rat model of evolutive prediabetes [Male Wistar rats, 8 weeks old] was developed by ingestion of a high-sucrose (HSu, 35%) diet for 9 weeks (W9), supplemented with a high-fat diet (HF, 60%) for further 14 weeks (HSuHF, W23), vs control with standard diet. Half of the animals (n = 10/group) daily received BJ (25g/Kg BW, orally) between W9 and W23. Along with metabolic characterization, BJ effects on serum and hepatic metabolic surrogates were elucidated using a 1H NMR based metabolomic approach. Moreover, the liver expression of genes (RT-PCR) involved in insulin signaling, lipid metabolism, inflammatory response and mitochondrial respiration was also explored. Values are means ± S.E.M (ANOVA followed by post-hoc tests).

Results

HSuHF+BJ rats restored hepatic levels of betaine and tend to recover the depletion of glutathione content found in HSuHF animals’ livers. Moreover, BJ positively affected the hepatic mRNA expression of key enzymes and mediators involved in fatty acid oxidation, insulin signalling, inflammatory response, as well as mitochondrial respiratory chain-related genes, which were all downregulated (P &lt; 0.05) in HSuHF animals’ livers.

Conclusions

Altogether, these molecular findings contribute to explain the mechanisms by which BJ elicits protection against hepatic steatosis and mitochondrial dysfunction induced by hypercaloric diets in the frame of prediabetes evolution.

Secondary Hyperparathyroidism Among Bariatric Patients: Unraveling the Prevalence of an Overlooked Foe

INTRODUCTION

Bariatric surgery (BS) is the most effective therapeutic approach to obesity. It is associated with great gastrointestinal anatomic changes, predisposing the patients to altered nutrient absorption that impacts phosphocalcium metabolism. This study aimed to clarify the prevalence of secondary hyperparathyroidism (SHPT) and its predictors in patients submitted to BS.

METHODS

Retrospective study of 1431 patients who underwent metabolic surgery between January 2010 and June 2017 and who were followed for at least 1 year. We compared the clinical and biochemical characteristics of patients with and without secondary hyperparathyroidism (considering SHPT a PTH ˃ 69 pg/mL). Two different analyses were performed: (1) paired analysis of participants before and 1 year after surgery (N = 441); (2) Cross sectional analysis of participants submitted to bariatric surgery before (N = 441), 1 year after (N = 1431) and 4 years after surgery (N = 333). Multiple logistic regression models were used to evaluate possible predictors of SHPT after BS.

RESULTS

The overall prevalence of SHPT was 24.9% before surgery, 11.2% 1 year after surgery and 21.3% 4 years after surgery. Patients submitted to LAGB had the highest prevalence of SHPT 1 year after surgery (19.4%; vs RYGB, 12.8%, vs SG, 5.3%). Four years after surgery, RYGB had the highest prevalence of SHPT (27.0%), followed by LAGB (13.2%) and SG (6.9%). Higher body mass index and age, decreased levels of vitamin D and RYGB seem to be independent predictors of SHPT 1 year after surgery. The only independent predictor of SHPT 4 years after surgery was RYGB.

CONCLUSION

The prevalence of SHPT is higher before and 4 years after BS than 1 year after surgery. This fact raises some questions about the efficacy of the implemented follow-up plans of vitamin D supplementation on the long term, mainly among patients submitted to RYGB.

Secondary Hyperparathyroidism Among Bariatric Patients: Unraveling the Prevalence of an Overlooked Foe

Introduction: Bariatric surgery (BS) is an effective therapeutic approach for obese patients. It is associated with important gastrointestinal anatomic changes, predisposing these subjects to altered nutrient absorption that impact phosphocalcium metabolism. This study aims to clarify the prevalence of secondary hyperparathyroidism (SHPT) and its predictors in patients submitted to BS. Methods: Retrospective unicentric study of 1431 obese patients who underwent metabolic surgery between January/2010 and June/2017 and who were followed for, at least, a year. In this group, 185 subjects were submitted to laparoscopic adjustable gastric banding (LAGB), 830 underwent Roux-en-Y gastric bypass (RYGB) and 416 sleeve gastrectomy (SG). Data comprising 4 years of follow-up were available for 333 patients. We compared the clinical and analytical characteristics of patients with and without secondary hyperparathyroidism (considering SHPT a PTH˃69pg/mL), taking also into account the type of surgery. A multiple logistic regression was performed to study the predictors of SHPT after BS. Results: The overall prevalence of SHPT before surgery was 24.9%, 11.2% one year after surgery and 21.3% four years after surgery. At 12 months after surgery, LAGB had the highest prevalence of patients with SHPT (19.4%, N=36), RYGB had 12.8% (N=274) and SG 5.3% (N=131). At 48 months after surgery, RYGB had the highest prevalence of SHPT (27.0%, N=222), LAGB had 13.2% (N=53) and SG 6.9% (N=58). Multi-variate logistic analysis showed that increased body mass index and age, decreased levels of vitamin D and RYGB were independent predictors of SHPT one year after surgery. The only independent predictor of SHPT four years after surgery was RYGB. Conclusion: The prevalence of SHPT is considerably higher before and four years after BS than 1 year after surgery. This fact raises some questions about the efficacy of the implemented follow-up plans of vitamin D supplementation on the long term, mainly among patients submitted to RYGB.

Bariatric Surgery Impact on Cardiovascular Risk Factors: Is Age a Factor to Consider?

INTRODUCTION

Despite the abundance of data addressing the influence of patient's age on surgery-related complications, its impact on cardiometabolic outcomes following bariatric surgery has been overlooked.

METHODS

Retrospective unicentric study of 1,728 obese patients who underwent bariatric surgery between January 2010 and June 2015. Patients were divided in 3 age groups, according to their age at surgery: ˂40 (n = 751), 40-59 (n = 879), and ≥60 years (n = 98). Parameters with cardiometabolic impact, such as body anthropometric measures, lipid profile, and glycemic status, before and 24 months after surgery, were compared between these groups. A multiple linear regression was performed, adjusting differences between groups for sex, surgery type, and body mass index variation.

RESULTS

The group ˂40 years presented more weight loss (-35.4 ± 9.0 kg, p ˂ 0.001), greater BMI reduction (-15.8 ± 6.1 kg/m2, p ˂ 0.001), and larger changes in waist (-34 ± 13.8 cm, p ˂ 0.001) and hip circumferences (-28.7 ± 11.9 cm, p ˂ 0.05). The group of ≥60 years presented the heaviest reduction in fasting glucose (-17.7 ± 32.8 mg/dL, p ˂ 0.001) and HbA1c (0.7 ± 1.0, p ˂ 0.001), and also had a tendency to have the biggest changes in systolic blood pressure (-14.7 ± 18.7 mm Hg, p = 0.071).

CONCLUSION

Patients with ≥60 years benefit the most from bariatric surgery regarding cardiometabolic parameters, presenting heavier reductions in fasting glucose, as well as HbA1c and a tendency towards a higher decrease in systolic blood pressure. No clinically significant differences in lipid profile were observed between groups.

The Impact of Vitamin D in Non-Alcoholic Fatty Liver Disease: A Cross-Sectional Study in Patients with Morbid Obesity

PURPOSE

We aimed to evaluate the association between vitamin D status and hepatic function parameters and scores: Fatty Liver Index (FLI, predictor of hepatic steatosis) and BARD (BMI, AST/ALT ratio and DM, predictor of hepatic fibrosis) in patients with morbid obesity.

PATIENTS AND METHODS

Cross-sectional study including patients with morbid obesity followed in our centre between January 2010 and July 2018. Patients with missing vitamin D levels or hepatic profile parameters were excluded. We divided the population according to two cut-offs of vitamin D levels (12ng/mL and 20ng/mL).

RESULTS

The included population (n=1124) had an average age of 43.3±10.7 years and 84.3% were female. Seventy-point eight percent of the population had vitamin D levels lower than 20ng/mL and 34.8% lower than 12ng/dL. Patients with lower vitamin D levels (<12ng/mL) had higher BMI, hip and waist circumferences and higher prevalence of hypertension. Higher FLI scores [OR= 0.77 (0.07), p<0.01] and ALP levels [β= -0.03 (-0.06, -0.01), p<0.01] associated to lower vitamin D levels.

CONCLUSION

Vitamin D deficiency is associated with a higher risk of hepatic steatosis in individuals with morbid obesity. Correction of vitamin D deficiency may have a beneficial role in the management of NAFLD in patients with morbid obesity.

Blueberries effects in experimental diet-induced prediabetes: a focus on renal impairment

Introduction Benefits arising from blueberry (BB) consumption are well-described in type 2 diabetes evolution and inherent complications. Lending further support to this thesis, previous work from our group unequivocally demonstrates BB supplementation efficacy to manage prediabetic hepatic liver steatosis. Whether a similar effect also holds truth in early renal impairment is an unsolved issue.

Objectives To address blueberry juice (BJ) ability to exert renoprotective effects in experimental prediabetes.

Methodology Diet-induced prediabetes [high-sucrose (35% Hsu) and high-fat (60% HF)] was developed in adult male Wistar rats through the ingestion of HSu for 9 weeks supplemented by HF for another 14 weeks (HSuHF, n = 16). On W9, half of the former animals orally received BJ (25g/kg BW, HSuHF+BJ). Control animals (n = 8) received standard diet during the entire protocol. Functional [serum and urinary creatinine, uric acid, glucose; glomerular filtration rate (GFR)], structural [H&E and Oil Red O staining] and molecular [triglycerides content and inflammation (RT-qPCR, WB)] markers of renal injury were assessed along with metabolic profile.

Results Even though diet-induced glucose intolerance, insulin insensitivity and plasmatic hypertriglyceridemia were significantly ameliorated upon BJ treatment, this nutraceutical intervention was unable to halt or slow down renal lipidosis and glomerular crescent-like lesions apart from a slight amelioration of both GFR and IL-6 levels in HSuHF-treated rats.

Conclusion Unlike previous results clearly demonstrating the ability of BJ nutraceutical intervention to afford protection against metabolic impairment and hepatic steatosis evolution in experimentally diet-induced prediabetes, only a modest renoprotective effect was observed in functional and morphological renal endpoints. Future studies are warranted to dissect the divergent effects of BJ on early liver and kidney impairment.

MON-584 Albuminuria and Obesity - Which Are the Associated Factors?

Introduction

The association between obesity and renal dysfunction has been widely studied. Albuminuria is a cardiovascular risk factor and the most prevalent marker of kidney injury in people with obesity. Despite the higher prevalence of hypertension and diabetes in those patients, other contributing factors are still unknown.

We aimed to explore the factors related to albuminuria in obesity, analyzing its variation after bariatric surgery.

Methods

We evaluated 2518 patients undergoing bariatric surgery, of those, 1243 with preoperative albuminuria measurement were included in this study. Albuminuria was determined by the albumin-creatinine ratio (RAC) in an occasional urine sample (mg/g) or by the 24-hour urine albumin excretion rate (TEA) (mg/24h). Means and medians were compared using Student’s T-test or Mann-Whitney tests, respectively. Spearman correlation was used.

Results Age (ρ = 0.073; p = 0.010), body mass index (BMI) (ρ = 0.139; p <0.001), waist circumference (WC) (ρ = 0.220; p <0.001), glycated hemoglobin (HbA1C) (ρ = 0.221; p <0.001), systolic blood pressure (SBP) (ρ = 0.203; p <0.001), diastolic blood pressure (DBP) (ρ = 0.134; p <0.001), uricemia (ρ = 0.141; p <0.001) and C-reactive protein (CRP) levels (ρ = 0.090; p = 0.017) were positively correlated with albuminuria.Patients with albuminuria (TEA / RAC≥30) had higher BMI (45.0 ± 6.0 vs.43.2 ± 5.6kg / m2; p <0.001), WC (129.3 ± 13.1 vs. 122.0 ± 12.9cm; p <0.001), SBP (142.7 ± 18.0 vs.134.1 ± 16.5mmHg; p <0.001), DBP (88.0 ± 12.6 vs.83, 2 ± 10.3mmHg; p <0.001), uricemia (6.1 ± 1.5 vs.5.4 ± 1.4mg / dL; p <0.001) and CRP (11.3 (16.4) vs.8, 3 (9.6) mg / L; p <0.001).Excluding patients with diabetes and hypertension, BMI and WC remained statistically positively correlated with urinary albumin excretion. After surgery, the decrease of albuminuria was correlated with the reduction of HbA1C (ρ = 0.144; p <0.001) and CRP (ρ = 0.113; p = 0.037).

Conclusion Anthropometric, inflammatory and metabolic factors, namely WC, CRP and uricemia, may be involved in the etiopathogenesis of albuminuria in obese patients. Bariatric surgery is the most effective method to reverse obesity and it has been shown to be a promising therapy on the treatment of associated renal dysfunction.

MON-592 The Impact of Bariatric Surgery on the Risk of Non-Alcoholic Fatty Liver Disease in Morbidly Obese Patients

Introduction: Non-alcoholic fatty liver disease (NAFLD) is strongly associated with obesity, and the prevalence of both diseases is increasing notably. The lack of effective treatment options for NAFLD is leading to a great consideration towards the identification of new approaches.

Aim: We aimed to evaluate the change one year after bariatric surgery of parameters of hepatic function and in the hepatic scores, Fatty Liver Index (FLI, predictor of hepatic steatosis), and BARD, BMI, AST/ALT ratio and DM, (predictor of hepatic fibrosis).

Methods: Observational retrospective cohort study in morbidly obese patients that underwent bariatric surgery between January 2010 and July 2018. We excluded patients missing hepatic function parameters before or one year after the surgical procedure. We used two linear regression models: 1) unadjusted; 2) adjusted for surgery type (gastric sleeve, gastric band and gastric bypass), sex, age, body mass index, diabetes and dyslipidaemia.

Results: The included population (n=1955) had an average age of 43.1±10 years and 85.8% were female. We observed a relevant decrease in transaminases (pre-operative AST and ALT, 24.8±12.4 and 29.5±19.5U/L, vs 22.4 ± 11.1 and 22.2±14.7 post-operatively, respectively, p&lt;0.01) and gamma-glutamyltransferase (36.9±35.4 vs 21.4±22.0U/L, p&lt;0.01), and an increase in alkaline phosphatase (77.8±23.5 vs 80.8±25.4U/L, p&lt;0.01) and total bilirubin (0.56±0.23 vs 0.68±0.24mg/dL, p&lt;0.01). Both FLI and BARD markedly decrease one year after surgery (p&lt;0.01). Comparing the surgical procedures, gastric sleeve was associated with a greater reduction of hepatic enzymes and of both FLI and BARD comparing with gastric band. Comparing with gastric bypass, sleeve was associated with a greater reduction of transaminases and alkaline phosphatase, but a smaller reduction of FLI and BARD.

Conclusion: Bariatric surgery is associated with a reduction of the hepatic enzymes and an improvement of FLI and BARD. Bariatric surgery may represent an effective therapeutic approach to NAFLD.

Assessment of pelvic floor muscles in sportswomen: Quality of life and related factors

OBJECTIVES

To evaluate Maximum Voluntary Contraction (MVC) of the Pelvic Floor Muscles (PFM) in sportswomen, to observe the urinary symptoms and their impact on the Quality of Life (QoL).

DESIGN

Observational cross-sectional study.

SETTING

Gyms and teams in the North of Portugal.

PARTICIPANTS

Sportswomen (n = 197).

MAIN OUTCOME MEASURES

The measurement was performed using a manometer. The sportswomen were instructed to perform 3 MVC of the perineum, held for 3 s. The Kings Health Questionnaire (KHQ) was used to evaluate urinary symptoms and the QoL of the sportswomen.

RESULTS

Age significantly influenced (p < 0.05) the QoL in all domains. An increase in BMI was also significantly associated with a decrease in the QoL. MVC values had a highly significant effect on the overall QoL and all domains, including a reduction in urinary symptoms. The weekly time of physical activity was associated with a better QoL in symptomatology. The practice of high-impact activities decreased the QoL (compared to low-impact activities). The vaginal resting pressure values ranged from 1.60 to 59.80 (24.34 ± 11.00).

CONCLUSIONS

Age, BMI and high-impact sports appear to be the leading factors that promote the onset of SUI, which in turn decrease the QoL in sportswomen. There was a positive association between MVC and weekly time of physical activity in the QoL.

Impact of Depression on Weight Variation after Bariatric Surgery: A Three-Year Observational Study

INTRODUCTION

The association between obesity and depression has been repeatedly established. However, little is known about the impact that the diagnosis of depression before bariatric surgery (DDBS) may have on weight loss.

OBJECTIVE

To evaluate the impact of DDBS on weight outcomes.

METHODS

Retrospective study of patients submitted to BS. Patients with no weight, no current medication data, or those submitted to revision surgery were excluded. Patients were considered to have DDBS based on taking antidepressants prior to BS or if there was a medical history of past or current depression. Patients with and without a depression history were compared using independent t test. A multivariate logistic regression model was created to evaluate predictors of weight variation (variables included: age, sex, and type of surgery).

RESULTS

A total of 616 patients did not have a history of depression and 230 had DDBS. There was a statistically significant difference in the BMI variation between groups. On average, individuals with DDBS lost 1.4 kg/m2 less than those without DDBS. In the multivariate analysis, the group with DDBS, compared with the group without DDBS, presented on average less -0.9 kg/m2 (95% CI -1.7 to -0.2, p = 0.018) BMI variation.

CONCLUSION

DDBS is a predictor of lower weight loss after the surgical procedure. Even after adjusting for confounding variables such as age, sex, and BS type, this effect remains.

Thyroid Function and the Risk of Non-Alcoholic Fatty Liver Disease in Morbid Obesity

BACKGROUND

An association between hypothyroidism and the risk of Non-alcoholic Fatty Liver Disease (NAFLD) has been suggested. This association remains to be elucidated in patients with morbid obesity.

AIM

To evaluate the association between thyroid function and parameters of liver function and hepatic scores in patients with morbid obesity.

METHODS

Patients with morbid obesity followed in our center between January 2010 and July 2018 were included. The ones without evaluation of liver and thyroid functions were excluded. Fatty Liver Index (FLI) and BARD scores were used as predictors of hepatic steatosis and fibrosis, respectively.

RESULTS

We observed a positive association between TSH and both BARD (OR 1.14; p = 0.035) and FLI (OR 1.19; p = 0.010) in the unadjusted analysis. We found a negative association between free triiodothyronine levels and BARD (OR 0.70; p<0.01) and a positive association between free triiodothyronine levels and FLI (OR 1.48; p = 0.022). Concerning liver function, we found a positive association between total bilirubin and free thyroxine levels (β = 0.18 [0.02 to 0.35]; p = 0.033) and a negative association between total bilirubin and free triiodothyronine levels (β = -0.07 [-0.14 to -0.002]; p = 0.042).

CONCLUSION

Higher levels of TSH and free triiodothyronine may be associated with a higher risk of NAFLD, particularly steatosis, in patients with morbid obesity.

Evening transitions of the atmospheric boundary layer: characterization, case studies and WRF simulations

Abstract. Micrometeorological observations from two months (July–August 2009) at the CIBA site (Northern Spanish plateau) have been used to evaluate the evolution of atmospheric stability and turbulence parameters along the evening transition to a Nocturnal Boundary Layer. Turbulent Kinetic Energy thresholds have been established to distinguish between diverse case studies. Three different types of transitions are found, whose distinctive characteristics are shown. Simulations with the Weather Research and Forecasting-Advanced Research WRF (WRF-ARW) mesoscale model of selected transitions, using three different PBL parameterizations, have been carried out for comparison with observed data. Depending on the atmospheric conditions, different PBL schemes appear to be advantageous over others in forecasting the transitions.

Observations and WRF simulations of fog events at the Spanish Northern Plateau

Abstract. The prediction of fogs is one of the processes not well reproduced by the Numerical Weather Prediction (NWP) models. In particular, the role of turbulence in the formation or dissipation of fogs is one of the physical processed not well understood, and therefore, not well parameterized by the NWP models. Observational analysis of three different periods with fogs at the Spanish Northern Plateau has been carried out. These periods have also been simulated with the Weather Research and Forecasting (WRF) numerical model and their results have been compared to observations. The study includes a comparison of the skill of different planetary boundary layer (PBL) parameterizations, surface layer schemes and a test of the gravitational settling of clouds/fogs droplets option. A statistical analysis of this comparison has been evaluated in order to study differences between the periods and between the various parameterizations used. The model results for each PBL parameterization were different, depending on the studied period, due to differences in the features of each fog. This fact made it difficult to obtain generalized conclusions, but allowed us to determine which parameterization performed better for each case. In general, judging from the models results of liquid water content (LWC), none of the PBL schemes were able to correctly simulate the fogs, being Mellor-Yamada Nakanishi and Niino (MYNN) 2.5 level PBL scheme the best one in most of the cases. This conclusion is also supported by the root mean square error (RMSE) calculated for different meteorological variables.

Seroprevalence of hepatitis B and C in the Western Brazilian Amazon region (Rio Branco, Acre): a pilot study carried out during a hepatitis B vaccination program

In 1999, on the occasion of the application of the first vaccine dose during the state vaccination campaign against hepatitis B virus (HBV), 390 individuals from the town of Rio Branco, Acre, aged two or more years were selected for the determination of the seroprevalence of HBV and HCV. HBV markers (HBsAg, anti-HBs, and anti-HBc IgG) were determined on this occasion and anti-HBs antibodies were also assessed 30 days after the third vaccine dose. At the time of vaccination, 39% of the individuals were still susceptible to HBV, while 61% presented serologic evidence of previous HBV contact or previous vaccination. The individuals with previous HBV contact were significantly older (p<0.001) than those without HBV markers. Of the 192 individuals who returned for reexamination, 30 days after the third dose, 158 (82.3%) had received three vaccine doses, and only 60 (31.2%) belonged to the group without HBV markers. In these individuals, the seroconversion rate after the third dose was 92% (55/60). In conclusion, we found considerable HBV in this population, indicating the need for pursuing the immunization programs. We also found high rates of vaccination coverage in the Western Brazilian Amazon region.

High-aspect-ratio line focus and plasma production using a random phase plate

The use of rectangular-element random phase plates to generate a line focus is described. Photographic records of the resultant focus are presented and compared with theoretical calculations made by using an interference code. Good agreement is found. The code is used to investigate possible design modifications to produce a more square-topped line focus. A 12-ps Raman-shifted KrF (lambda = 0.268 microm) laser pulse is used in combination with such plates to produce a laser plasma. The plasma conditions are extensively characterized by using time-resolved extreme UV spectroscopy and a pinhole camera, and their suitability for x-ray laser applications is discussed.

Time resolved imaging at 130 A with submicron resolution

A novel and simple XUV imaging technique using a laser-produced plasma source is described. A spatial resolution of better than 0.8 mum is demonstrated.