Testing machine learning algorithms for the prediction of depositional fluxes of the radionuclides 7Be, 210Pb and 40K

The monthly depositional fluxes of ⁷Be, ²¹⁰Pb and ⁴⁰K were measured at Malaga, (Southern Spain) from 2005 to 2018. In this work, the depositional fluxes of these radionuclides are investigated and their relations with several atmospheric variables have been studied by applying two popular machine learning methods: Random Forest and Neural Network algorithms. We extensively test different configurations of these algorithms and demonstrate their predictive ability for reproducing depositional fluxes. The models derived with Neural Networks achieve slightly better results, in average, although similar, having into account the uncertainties. The mean Pearson-R coefficients, evaluated with a k-fold cross-validation method, are around 0.85 for the three radionuclides using Neural Network models, while they go down to 0.83, 0.79 and 0.8 for ⁷Be, ²¹⁰Pb and ⁴⁰K, respectively, for the Random Forest models. Additionally, applying the Recursive Feature Elimination technique we determine the variables more correlated with the depositional fluxes of these radionuclides, which elucidates the main dependences of their temporal variability.

Phenotype and natural history of elderly onset inflammatory bowel disease: a multicentre, case-control study

BACKGROUND

Onset during old age has been reported in upto 10% of total cases of inflammatory bowel disease (IBD).

AIM

To evaluate phenotypic characteristics and the use of therapeutic resources in patients with elderly onset IBD.

METHODS

Case-control study including all those patients diagnosed with IBD over the age of 60 years since 2000 who were followed-up for >12 months, identified from the IBD databases. Elderly onset cases were compared with IBD patients aged 18 to 40 years at diagnosis, matched by year of diagnosis, gender and type of IBD (adult-onset).

RESULTS

One thousand three hundred and seventy-four elderly onset and 1374 adult-onset cases were included (62% ulcerative colitis (UC), 38% Crohn's disease (CD)). Among UC patients, elderly onset cases had a lower proportion of extensive disease (33% vs 39%; P < 0.0001). In CD, elderly onset cases showed an increased rate of stenosing pattern (24% vs 13%; P < 0.0001) and exclusive colonic location (28% vs 16%; P < 0.0001), whereas penetrating pattern (12% vs 19%; P < 0.0001) was significantly less frequent. Regarding the use of therapeutic resources, there was a significantly lower use of corticosteroids (P < 0.0001), immunosuppressants (P < 0.0001) and anti-TNFs agents (P < 0.0001) in elderly onset cases. Regarding surgery, we found a significantly higher surgery rate among elderly onset UC cases (8.3% vs 5.1%; P < 0.009). Finally, elderly onset cases were characterised by a higher rate of hospitalisations (66% vs 49%; P < 0.0001) and neoplasms (14% vs 0.5%; P < 0.0001).

CONCLUSIONS

Elderly onset IBD shows specific characteristics and they are managed differently, with a lower use of immunosuppressants and a higher rate of surgery in UC.

7Be, 210Pb and 40K depositions over 11 years in Málaga

The monthly bulk depositional fluxes of three natural radionuclides (⁷Be, ²¹⁰Pb and ⁴⁰K) were measured at a Mediterranean coastal station (Málaga) over an 11-year period from 2005 to 2015. The mean annual depositional fluxes of ⁷Be, ²¹⁰Pb and ⁴⁰K were 1215, 144 and 67 Bq m^-2 year^-1 respectively, showing a clear seasonal trend with minimum values recorded during summer and maximum values in winter. The rainfall regime with dry summers allows estimating the dry deposition. Assuming constant dry deposition through each year, ⁷Be, ²¹⁰Pb and ⁴⁰K would account for 12.5, 26.5 and 33% of the bulk fallout respectively which indicates that deposition for ²¹⁰Pb and ⁴⁰K are significantly higher than ⁷Be. The precipitation-normalized enrichment factor alpha used to explain seasonal variations in the depositional fluxes of radionuclides with respect the rainfall, indicates higher depositional fluxes during spring and summer than expected from the amount of rainfall. Despite their different origin, ²¹⁰Pb and ⁷Be monthly depositional fluxes have strong correlation. The atmospheric deposition fluxes of ⁷Be, ²¹⁰Pb and ⁴⁰K were controlled mainly by the amount of rainfall (r = 0.89, 0.91 and 0.66 respectively). Moreover, principal component analysis was applied to the datasets and deposition of radionuclides and rainfall in the same component highlighting the importance of the washout mechanism. The mean depositional velocity of aerosols evaluated using ⁷Be and ²¹⁰Pb are similar and are compared to other published values.

Evidence-based guides in tracheostomy use in critical patients

OBJECTIVES

Provide evidence based guidelines for tracheostomy in critically ill adult patients and identify areas needing further research.

METHODS

A task force composed of representatives of 10 member countries of the Pan-American and Iberic Federation of Societies of Critical and Intensive Therapy Medicine and of the Latin American Critical Care Trial Investigators Network developed recommendations based on the Grading of Recommendations Assessment, Development and Evaluation system.

RESULTS

The group identified 23 relevant questions among 87 issues that were initially identified. In the initial search, 333 relevant publications were identified of which 226 publications were chosen. The task force generated a total of 19 recommendations: 10 positive (1B=3, 2C=3, 2D=4) and 9 negative (1B=8, 2C=1). A recommendation was not possible in six questions.

CONCLUSION

Percutaneous techniques are associated with a lower risk of infections compared to surgical tracheostomy. Early tracheostomy only seems to reduce the duration of ventilator use but not the incidence of pneumonia, the length of stay, or the long-term mortality rate. The evidence does not support the use of routine bronchoscopy guidance or laryngeal masks during the procedure. Finally, proper prior training is as important or even a more significant factor in reducing complications than the technique used.

Time trends in the aetiology of prosthetic joint infections: a multicentre cohort study

It is important to know the spectrum of the microbial aetiology of prosthetic joint infections (PJIs) to guide empiric treatment and establish antimicrobial prophylaxis in joint replacements. There are no available data based on large contemporary patient cohorts. We sought to characterize the causative pathogens of PJIs and to evaluate trends in the microbial aetiology. We hypothesized that the frequency of antimicrobial-resistant organisms in PJIs has increased in the recent years. We performed a cohort study in 19 hospitals in Spain, from 2003 to 2012. For each 2-year period (2003-2004 to 2011-2012), the incidence of microorganisms causing PJIs and multidrug-resistant bacteria was assessed. Temporal trends over the study period were evaluated. We included 2524 consecutive adult patients with a diagnosis of PJI. A microbiological diagnosis was obtained for 2288 cases (90.6%). Staphylococci were the most common cause of infection (1492, 65.2%). However, a statistically significant rising linear trend was observed for the proportion of infections caused by Gram-negative bacilli, mainly due to the increase in the last 2-year period (25% in 2003-2004, 33.3% in 2011-2012; p 0.024 for trend). No particular species contributed disproportionally to this overall increase. The percentage of multidrug-resistant bacteria PJIs increased from 9.3% in 2003-2004 to 15.8% in 2011-2012 (p 0.008), mainly because of the significant rise in multidrug-resistant Gram-negative bacilli (from 5.3% in 2003-2004 to 8.2% in 2011-2012; p 0.032). The observed trends have important implications for the management of PJIs and prophylaxis in joint replacements.

Study of ⁷Be and ²¹⁰Pb as radiotracers of African intrusions in Malaga (Spain)

The relationship between the particulate matter in the atmosphere of Malaga and the origin of air masses with special attention to African intrusions was analyzed. The concentrations of PM10 and the activities of some radionuclides ((7)Be and (210)Pb) as tracers of these intrusions are discussed. The origin of these radiotracers is completely different. (210)Pb is a good tracer of air masses traveling close to the ground and come from inland areas. On the other hand, the production of (7)Be is very low in the vicinity of the Earth's surface, and increases with altitude, making it a great tracer of stratospheric air masses in the troposphere. Studies of radionuclide activities in aerosol particles provide a means for evaluating the integrated effects of transport and meteorology on the atmospheric loadings of substances with different sources. Measurements of aerosol mass concentration and specific activities of (7)Be and (210)Pb in aerosols at Malaga (36° 43' 40″ N; 4° 28' 8″ W) for the period 2009-2011 were used to obtain the relationships between radionuclide activities and airflow patterns by comparing the data grouped by air mass trajectory. The average concentration values of (7)Be and (210)Pb over the 3-year period have been found to be 5.05 and 0.55 mBq m(-3), respectively, with mean aerosol mass concentration of 53.6 μg m(-3). Taking into account the outbreaks of the daily values limits of PM10 in the study period (2009-2011), the origin of air masses is studied to explain three different situations of both radionuclides (7)Be and (210)Pb: 1) high concentrations of (7)Be and low concentrations of (210)Pb; 2) high concentrations of (210)Pb and low concentrations of (7)Be and 3) high concentrations of (7)Be and (210)Pb.

Behavior of ambient concentrations of natural radionuclides (7)Be, (210)Pb, (40)K in the Mediterranean coastal city of Málaga (Spain)

During a 4-year period (January 2009-December 2012), the (7)Be, (210)Pb, and (40)K activity concentrations in airborne particulate matter were weekly determined at the Málaga (Spain) located in the southern Iberian Peninsula. Totally 209 polypropylene filters were analyzed in the mentioned period. In 100% of the filters, (7)Be and (40)K activity concentrations were detected while (210)Pb activity concentration was detected in 96% of the filters. The results from individual measurements of (7)Be, (210)Pb, and (40)K concentrations were analyzed to derive the statistical estimates characterizing the distributions. Principal components analysis (PCA) was applied to the datasets and the results of the study reveal that aerosol behavior is represented by two principal components which explain 73.2% of total variance. Components PC1 and PC2 respectively explain 46.0 and 27.2% of total variance. PC1 was related positively to dust content, (7)Be and (40)K concentrations and negatively to sunspot numbers. In contrast, PC2 was related positively to temperature and (210)Pb activity and negatively to precipitation and relative humidity. The (7)Be levels showed a significant correlation with sunspot numbers due to the cosmogenic origin. (40)K activities showed a good correlation with dust deposition in filters mainly because it was transported to the air as resuspended particle from the soil. An inverse relationship was observed between the (210)Pb concentrations and monthly rainfall, indicating washout of atmospheric aerosols carrying these radionuclides and a pronounced positive correlation with the average monthly temperature of air.

Rational application of adenosine deaminase activity in cerebrospinal fluid for the diagnosis of tuberculous meningitis

PURPOSE

Tuberculous meningitis (TBM) is one of the most serious and difficult to diagnose manifestations of TB. An ADA value >9.5 IU/L has great sensitivity and specificity. However, all available studies have been conducted in areas of high endemicity, so we sought to determine the accuracy of ADA in a low endemicity area.

METHODS

This retrospective study included 190 patients (105 men) who had ADA tested in CSF for some reason. Patients were classified as probable/certain TBM or non-TBM based on clinical and Thwaite's criteria. Optimal ADA cutoff was established by ROC curves and a predictive algorithm based on ADA and other CSF biochemical parameters was generated.

RESULTS

Eleven patients were classified as probable/certain TBM. In a low endemicity area, the best ADA cutoff was 11.5 IU/L with 91 % sensitivity and 77.7 % specificity. We also developed a predictive algorithm based on the combination of ADA (>11.5 IU/L), glucose (<65 mg/dL) and leukocytes (≥13.5 cell/mm(3)) with increased accuracy (Se: 91 % Sp: 88 %).

CONCLUSIONS

Optimal ADA cutoff value in areas of low TB endemicity is higher than previously reported. Our algorithm is more accurate than ADA activity alone with better sensitivity and specificity than previously reported algorithms.

Lack of association between genotypes and haematogenous seeding infections in a large cohort of patients with methicillin-resistant Staphylococcus aureus bacteraemia from 21 Spanish hospitals

There is increasing concern regarding the association between certain methicillin-resistant Staphylococcus aureus (MRSA) genotypes and poor clinical outcome. To assess this issue, a large cohort of 579 subjects with MRSA bacteraemia was prospectively followed from June 2008 to December 2009, in 21 hospitals in Spain. Epidemiology, clinical data, therapy, and outcome were recorded. All MRSA strains were analysed in a central laboratory. Presence of a haematogenous seeding infection was the dependent variable in an adjusted logistic regression model. Of the 579 patients included in the study, 84 (15%) had haematogenous seeding infections. Microdilution vancomycin median MIC (IQR) was 0.73 (0.38-3) mg/L. Most MRSA isolates (n = 371; 67%) belonged to Clonal Complex 5 (CC5) and carried an SCCmec element type IV and agr type 2. Isolates belonging to ST8-agr1-SCCmecIV, ST22-agr1-SCCmecIV and ST228-agr2-SCCmecI--a single locus variant of ST5--accounted for 8%, 9% and 9% of the isolates, respectively. After adjusting by clinical variables, any of the clones was associated with increased risk of haematogenous seeding infections. Higher vancomycin MIC was not identified as an independent risk factor, either. In contrast, persistent bacteraemia (OR 4.2; 2.3-7.8) and non-nosocomial acquisition (3.0; 1.7-5.6) were associated with increased risk.

Safety of thiopurines and anti-TNF-α drugs during pregnancy in patients with inflammatory bowel disease

OBJECTIVES

The safety of thiopurines and anti-tumor necrosis factor-α (TNF-α) drugs during pregnancy remains controversial, as the experience with these drugs in this situation is limited. Our aim is to assess the safety of thiopurines and anti-TNF-α drugs for the treatment of inflammatory bowel disease (IBD) during pregnancy.

METHODS

Retrospective, multicenter study in IBD patients. Pregnancies were classified according to the therapeutic regimens during pregnancy or during the 3 months before the conception: non-exposed group, pregnancies exposed to thiopurines alone (group A), and pregnancies exposed to anti-TNF-α drugs (group B). An unfavorable Global Pregnancy Outcome (GPO) was considered if pregnancy developed with obstetric complications in the mother and in the newborn.

RESULTS

A total of 187 pregnancies in the group A, 66 pregnancies in the group B, and 318 pregnancies in the non-exposed group were included. The rate of unfavorable GPO was different among the three groups (31.8% in non-exposed group, 21.9% in group A, and 34.8% in group B), being lower in pregnancies under thiopurines than among non-exposed (P = 0.01). The rate of pregnancy complications was similar among the three groups (27.7% in non-exposed, 20.9% in group A, and 30.3% in group B). The rate of neonatal complications was different among the three groups (23.3% in non-exposed group, 13.9% in group A, and 21.2% in group B), being lower in pregnancies under thiopurines than among non-exposed (P = 0.01). In the multivariate analysis, the treatment with thiopurines (odds ratio = 0.6; 95% confidence interval = 0.4-0.9, P = 0.02) was the only predictor of favorable GPO, whereas maternal age >35 years at conception was the only predictor of unfavorable GPO. The treatment with anti-TNF-α drugs was not associated with an unfavorable GPO.

CONCLUSION

The treatment with thiopurines and anti-TNF-α drugs does not seem to increase the risk of complications during pregnancy and does seem to be safe for the newborn.

Effects of collector types in sampling of atmospheric depositional fluxes

The bulk gross alpha, gross beta and (7)Be depositional fluxes were measured in Málaga (36.7 degrees N, 4.5 degrees W), a coastal Mediterranean station in the south of Spain for one whole year. In order to quantify the local variation of deposition rates, we have analysed the monthly results from two deposition collectors: a "pot "collector with a continuous water-covered surface and a "funnel" collector. In general, the alpha and beta depositional fluxes from the funnel collector were approximately two times lower than the pot collector. Whereas for the cosmogenic (7)Be, the depositional flux of (7)Be from funnel collector was also approximately two times lower than the pot collector. A good correlation of the depositional flux of (7)Be has been obtained from both collectors.

Exhalation of (222)Rn from phosphogypsum piles located at the Southwest of Spain

Phosphogypsum (PG) is a waste product of the phosphoric acid production process and contains, generally, high activity concentrations of uranium series radionuclides. It is stored in piles formed over the last 40 years close to the town of Huelva (Southwest of Spain). The very broad expanse of the PG piles (about 1200 ha) produces a local, but unambiguous, radioactive impact to their surroundings. In 1992, the regional government of Andalusia restored an area of 400 ha by covering it with a 25-cm thick layer of natural soil and, currently, there is an additional zone of 400 ha in course of restoration (unrestored) and the same area of active PG stacks. Due to the high activity concentration of (226)Ra in active PG stacks (average 647 Bq kg(-1)), a significant exhalation of (222)Rn could be produced from the surface of the piles. Measurements have been made of (222)Rn exhalation from active PG stacks and from restored and unrestored zones. The (222)Rn exhalation from unrestored zones is half of that of the active PG stacks. Following restoration, the (222)Rn exhalation is approximately eight times lower than the active PG stacks. The activity concentrations of natural radionuclides ((226)Ra, (40)K, (232)Th) in the mentioned zones have been determined. This study was also conducted to determine the effect of (226)Ra activity concentration on the (222)Rn exhalation, and a good correlation was obtained between the (222)Rn exhalation and (226)Ra activity, porosity and density of soil.

Stochastic model to forecast ground-level ozone concentration at urban and rural areas

Stochastic models that estimate the ground-level ozone concentrations in air at an urban and rural sampling points in South-eastern Spain have been developed. Studies of temporal series of data, spectral analyses of temporal series and ARIMA models have been used. The ARIMA model (1,0,0) x (1,0,1)24 satisfactorily predicts hourly ozone concentrations in the urban area. The ARIMA (2,1,1) x (0,1,1)24 has been developed for the rural area. In both sampling points, predictions of hourly ozone concentrations agree reasonably well with measured values. However, the prediction of hourly ozone concentrations in the rural point appears to be better than that of the urban point. The performance of ARIMA models suggests that this kind of modelling can be suitable for ozone concentrations forecasting.

Analyses of ozone in urban and rural sites in Málaga (Spain)

Ozone concentrations were measured at two (urban and a rural) sites near the city of Málaga (Spain). The aim of this study was to determine the daily, monthly and seasonal variation patterns of ozone concentrations at both sites and to study the possible regional influences. The daily variations mostly have the usual features with the afternoon maximum and the night minimum being more pronounced in the urban area. The average monthly concentrations throughout the year start to increase in March reaching their maximum values in July for the urban site. However, in the rural area, the monthly variations are smaller reaching their maximum value in June. The hourly evolution of the ozone concentrations in both sampling sites is well defined in spring and summer and not so well defined in autumn and winter. Taking into account the four seasons, the rural concentrations are higher than the urban ones. Summer is the season when there are similar concentrations at both sampling sites. Average hourly summer afternoon ozone for the hours 12:00-20:00 LST exceeded the 110 microg m(-3) European Union guidelines for human health for 8 h ozone exposure at the urban and rural sites.

Sediment accumulation rate and radiological characterisation of the sediment of Palmones River estuary (southern of Spain)

Chemical analyses and radioecological methods were combined in order to estimate the sediment accumulation rate in the upper 20 cm depth of the Palmones River estuary. Organic matter, total carbon, C:N and (137)Cs vertical profiles showed changes at 13 cm depth. These changes could be associated with the decrease in river input since 1987 when a dam situated in the upper part of the estuary started to store water. Using 1987 as reference to date the sediment, accumulation rate was 1.2 cm yr(-1). As alternative method, two layer model of (210)Pb(xs) vertical distribution showed a sedimentation rate of 0.7 cm yr(-1) with a surface mixing layer of 7 cm thickness. The high ammonium, potassium and sodium content in pore water and the strong correlation between (137)Cs activities and organic matter in dry sediment suggests that (137)Cs (the only anthropogenic product detected) is mainly accumulated in the estuary associated with the particulate organic material from the catchment area.

Assessment of ozone variations and meteorological effects in an urban area in the Mediterranean Coast

Ozone concentrations are valuable indicators of possible health and environmental impacts. However, they are also used to monitor changes and trends in the sources of both ozone and its precursors. For this purpose, the influence of meteorological variables is a confusing factor. This study presents an analysis of a year of ozone concentrations measured in a coastal Spanish city. Firstly, the aim of this study was to perceive the daily, monthly and seasonal variation patterns of ozone concentrations. Diurnal cycles are presented by season and the fit of the data to a normal distribution is tested. In order to assess ozone behaviour under temperate weather conditions, local meteorological variables (wind direction and speed, temperature, relative humidity, pressure and rainfall) were monitored together with ozone concentrations. The main relationships we could observe in these analyses were then used to obtain a regression equation linking diurnal ozone concentrations in summer with meteorological parameters.

Gross-alpha and gross-beta activities in airborne particulate samples. Analysis and prediction models

Measurements of gross-alpha and gross-beta activities were made every week during the years 1992-1997 for airborne particulate samples collected using air filters at a clear site. The data are sufficiently numerous to allow the examination of variations in time and by these measurements to establish several features that should be important in understanding any trends of atmospheric radioactivity. Two models were used to predict the gross-alpha and gross-beta activities. A good agreement between the results of these models and the measurements was highlighted.

[Viability of colonoscopy without analgesia and conscious sedation]

AIM

To study the need for analgesia and sedation before colonoscopy.

PATIENTS AND STUDY DESIGN

Fifty consecutive outpatients were randomly assigned to receive meperidine (0.7 mg/kg) or midazolam (0-035 mg/kg) intravenously (n = 25) or to receive no medication (n = 25) before colonoscopy. Oxygen saturation (SaO2) and heart rate were monitored. Mean blood pressure (MBP) was recorded before and after endoscopy. Patients in the group receiving no medication who experienced marked abdominal pain received sedation and analgesia similar to the premedicated group. Twenty-four hours after the procedure, the patients evaluated the degree of abdominal pain experienced during colonoscopy on a scale from 0 to 9.

RESULTS

Complete colonoscopy was performed in 92% of the patients. No significant changes in heart rate were registered in either group. However, in the premedicated group mean blood pressure fell significantly (97.6 +/- 2.6 vs. 89.5 +/- 2.7 mmHg) before and after colonoscopy, respectively (p < 0.05). Nine patients experienced clinically relevant oxygen desaturation (SaO2 > 90%). Of these, five were from the premedicated group and four were from the group receiving no medication. In two patients, both from the premedicated group, the decrease in SaO2 was severe (SaO2 < 85%). The degree of abdominal pain was similar in both groups: 3.64_0.47 (premedicated) vs. 3.92 +/- 0.5 (non-medicated). In the non-medicated group, two patients required analgesia and sedation to complete the colonoscopy and 20 (80%) preferred not to receive sedation in future colonoscopies.

CONCLUSIONS

Colonoscopy may be well tolerated without systematic administration of sedation and analgesia, which could be administered selectively.

[Prospective study of gastroesophageal reflux after esophageal variceal band ligation]

In recent years, variceal ligation has been introduced as an alternative treatment to endoscopic sclerotherapy.

AIM

To evaluate the occurrence of excess gastroesophageal reflux in cirrhotic patients with esophageal varices eradicated by band ligation.

PATIENTS AND METHODS

Twenty-six cirrhotic patients with esophageal varices underwent band ligation until variceal eradication. pH monitoring was carried out in all patients before inclusion in the eradication program and again at the end. The results were evaluated according to De Meester's criteria.

RESULTS

Five patients presented excess gastroesophageal reflux before the beginning of treatment. A further six patients developed excess gastroesophageal reflux after endoscopic treatment. The only factor implicated in the development of excess gastroesophageal reflux was the use of sclerosant at the end of treatment to ensure complete eradication: five of the eight who needed sclerosant developed excess gastrophageal reflux, while only two of the 16 treated without sclerosant did so (p < 0.01).

CONCLUSION

Esophageal variceal band ligation does not significantly provoke excess gastroesophageal reflux if sclerosant is not used in the endoscopic technique.

Idiopathic portal hypertension and angiosarcoma associated with arsenical salts therapy

We describe a 60-year-old man with idiopathic portal hypertension and hepatic angiosarcoma. The patient had taken an arsenical preparation for the treatment of psoriasis for 10 years. Five cases of this association have been reported previously; in one only, exposure to arsenical salts was present.

[Chylous ascites in cirrhotic and non-cirrhotic patients]

Chylous ascites is an accumulation of lymph in the abdominal cavity. The diagnosis is established when the concentration of triglycerides in plasma is greater than in ascitic fluid over a level of 200 mg/dl. The clinical and biochemical characteristics of 22 patients with chylous ascites (11 cirrhotics and 11 non cirrhotics) were studied in order to assess differences between patients with and without hepatic cirrhosis. The cirrhotic patients with chylous ascites showed lower protein (1.3 +/- 0.74 mg/dl, p = 0.002) and cholesterol concentration (46.0 +/- 45.2 mg/dl, p = 0.02) in ascitic fluid than non cirrhotic patients (3.1 +/- 1.09 mg/dl, and 100.85 +/- 41.7 mg/dl, respectively). In addition, the cellularity in the ascitic fluid was also lower in cirrhotic patients (209.09 +/- 113.96 cel/mm3) versus (831.8 +/- 945.08 cel/mm3; p < 0.05). Four patients (18.18%) presented high adenosine deaminase levels (ADA) in the ascitic fluid in the absence of tuberculous peritonitis. The authors conclude that the biochemical differences observed in the ascitic fluid of the cirrhotic patients with chylous ascites may be explained by a dilutional mechanism due to the combination of "clear" ascites secondary to portal hypertension and chylous ascites. Furthermore, chylous ascites could be the cause of an elevation in ADA in the absence of tuberculous peritonitis.

Value of endothelin in cellular rejection after liver transplantation

Endothelin-1 is a vasoconstrictor peptide released by the vascular endothelium by various chemical and mechanical factors. Cellular rejection is one of the most common complications following orthotopic liver transplantation, endotheliitis being its most specific and consistent histological feature. To assess the role of endothelin in cellular hepatic rejection, we studied 21 cirrhotic patients undergoing elective liver transplantation. These patients were divided in two groups: Group I comprised 10 patients without cellular rejection, and Group II comprised 11 patients with cellular rejection. Endothelin was measured on day 7 after transplantation, on the day of liver biopsy, and after treatment for rejection. We found a significant increase in the plasma endothelin levels in the early postoperative period in the patients with moderate or severe cellular rejection compared with the non-rejection group. It remained significantly elevated until the clinical diagnosis of rejection was made. This value returned to baseline with successful treatment. So, the monitorization of this peptide may be of help in the diagnosis of rejection, its severity, and the evaluation of its resolution.

[Recurrence of hepatitis caused by hepatitis c virus in patients receiving a liver transplant]

BACKGROUND

Liver disease due to hepatitis C virus (HCV) is an increasingly frequent indication for liver transplantation. We performed a clinical and virological study of 20 HCV-infected liver transplant recipients to correlate virological markers with histological recurrence of disease.

PATIENTS AND METHODS

In ninety-four patients who were given transplants for end-stage cirrhosis, IgG and IgM antibodies to HCV and IgM to HCV tested by ELISA; all samples were further examined in a four-antigen recombinant immunoblot assay (2-RIBA). HCV viremia was measured by the conventional nested PCR, HCV genotype was determined by PCR amplification using type-specific primers. We have analyzed de novo infection by HCV, HCV recurrence and the influence of genotype in these recurrence.

RESULTS

Nineteen of 20 antibody-positive patients (95%) had HCV RNA before transplantation. All 19 patients who were viremic before transplantation had persistent infection after LT. HCV genotype 1b was the predominant type before and after LT (75%). Ten of the 20 (50%) patients developed histological findings of chronic hepatitis (CH) in liver allografts. HCV recurrent liver disease after LT was not related with HCV genotype. Of 4 deaths after transplant in hepatitis C group, only one was related to recurrent disease. We have not found de novo hepatitis C.

CONCLUSIONS

Our results indicate the general persistence of hepatitis C virus infection and the excellent short-term prognosis after liver transplantation. Chronic hepatitis by HCV in liver transplant was not related with HCV genotype.

[Hepatita B and C virus infections in patients with hepatocellular carcinoma]

BACKGROUND

The prevalence of HBV and HCV infections in patients with hepatocellular carcinoma may be related to variations in the geographic area of study. For this reason, we have analized the relative prevalence of HBV and HCV infections in 94 patients with hepatocellular carcinoma from Cantabria (North of Spain).

PATIENTS AND METHODS

We have studied 94 patients with hepatocellular carcinoma from January 1988 to December 1993. Commercially available radioimmunoassay or ELISA were used for detection of HBsAg, anti-HBs and anti-HBc. The HBV DNA was analized by PCR. The HCV infection was assayed by ELISA-2 and RT-PCR.

RESULTS

The HBV infection was detected in 27 patients: 19 patients were HBsAg positive and 8 patients HBsAg negative, anti-HBc positive, DNA HBV positive by PCR. The HCV infection was found in 57 patients. Forty patients were infected with both viruses. Of the remain twenty-four, forty were alcoholics. We found in 61 patients more than one etiological factor. Hepatoma was the first manifestation of liver disease in 24 cases and these were more frequently in HCV than in those with HBV infection. Moreover, the first group were older and have lower alcohol intake.

CONCLUSIONS

1) In Cantabria, Spain, the majority of cases of hepatocellular carcinoma are related to HBV, HCV and alcohol. 2) Analysis of DNA HBV and RNA HCV by PCR allows the diagnosis of cryptic infections by both viruses, especially in the cases of HBV and HCV coinfection. 3) Hepatoma is the first manifestation of liver disease in a high percentage of cases.

[Analysis of the DNA of the hepatitis B virus (HBV) in the serum and mononuclear cells of the peripheral blood in subjects with chronic infection by the HBV]

BACKGROUND

Viral replication is one of the determining factors of the natural history of infection by the hepatitis B virus (HBV). The clinical significance of the viremia and the DNA-HBV findings in mononuclear cells was therefore analyzed.

METHODS

The epidemiologic history, liver function tests and the Knodell index were analyzed in 117 patients with chronic hepatitis B (CHB) and 33 healthy HBV carriers. The DNA-HBV was studied in serum and mononuclear cells by dot-blot and polymerase chain reaction (PCR).

RESULTS

The DNA-HBV was detected by dot-blot in 62/117 subjects with and in CHB 3/33 healthy carriers. Viremis was determined by PCR in 107/117 patients with CHB and in 22/23 healthy carriers. Both aspartate aminotransferase (AST) as well as alanine aminotransferase (ALT) and the Knodell index were greater in the patients with positive DNA-HBV dot-blot. No significant differences were observed in the liver function tests and Knodell index with regard to the viremia detectable exclusively by PCR. In the mononuclear cells of peripheral blood, DNA-HBV was observed in 62% by dot-blot and in 95% by PCR. The presence of DNA-HBV by dot-blot in these cells was associated to greater disease activity.

CONCLUSIONS

The activity of chronic hepatitis B was correlated with the presence of high viremic levels with no direct relation being observed between low grade viremia and disease aggressivity. The finding of DNA-HBV by dot-blot in mononuclear cells was associated with a greater activity of chronic hepatitis B, with these results being in agreement with the serologic data reported.

[Duodenal diverticula associated with acute pancreatitis]

The purpose of this study was to assess the role of duodenal diverticula as an etiologic factor in acute pancreatitis.

METHODS AND PATIENTS

We have reviewed the records of patients with diverticulum of the second portion of the duodenum diagnosed by gastroduodenal radiology or endoscopy during the period 1991-1992 in our hospital. As a control group we studied patients without duodenal diverticulum. All subjects underwent biliary-pancreatic ultrasonography. Thirty-eight patients had a duodenal diverticulum and gallstones 36 had a duodenal diverticulum but no gallstones; 21 had gallstones alone; and, finally, 42 patients were free of duodenal diverticulum and gallstones.

RESULTS

Patients with duodenal diverticula had a greater prevalence of gallstones than those without (51.3% VS 33.3%, p < 0.005). Of the thirty-eight patients with duodenal diverticula and gallstones 23.7% had acute pancreatitis. None of the 21 patients without duodenal diverticulum and with gallstones had acute pancreatitis, p < 0.05. The median age of patients with duodenal diverticulum without gallstones was 64.25 years, range 34-85, and the age of those with duodenal diverticulum and gallstones was 70.4 years, range 37-87, p < 0.05.

CONCLUSIONS

1) Gallstones may cause acute pancreatitis in patients with D2 duodenal diverticula. 2) Patients with a D2 duodenal diverticulum frequently have gallstones. 3) The fact that the age of patients with duodenal diverticulum was lower than that of patients with both duodenal diverticulum and gallstones suggests that duodenal diverticula may play a role in the pathogenesis of gallstones.

Consumption of methane by soils

Measurements of the methane flux and methane concentration profiles in soil air are presented. The flux of methane from the soil is calculated by two methods: a) Direct by placing a static open chamber at the soil surface. b) Indirect, using the (222)Rn concentrations profile and the (222)Rn flux in the soil surface in parallel with the methane concentration ((222)Rn calibrated fluxes). The methane flux has been determined in two kinds of soils (sandy and loamy) in the surroundings of Málaga (SPAIN). The directly measured methane fluxes at all investigated sites is higher than methane fluxes derived from "Rn calibrated fluxes". Atmospheric methane is consumed by soils, mean direct flux to the atmosphere were - 0.33 g m(-2)yr-1. The direct methane flux is the same within the measuring error in sandy and loamy soils. The influence of the soil parameters on the methane flux indicates that microbial decomposition of methane is primarily controlled by the transport of methane.