Connectivity and hydrological efficiency dynamics at active volcanoes, Mexico.

Connectivity is an emergent property that describes how complex topography favors or impedes sediment transfer processes. In active volcanic areas, high connectivity may lead to extremely efficient processes, such as lahars. The aim of the present study is to examine the behavior (activation-deactivation) of sub-basins affected by volcanic and anthropogenic processes by studying the changes in connectivity and hydrological efficiency. Two volcanic zones in Mexico were selected: Volcán de Colima and Popocatépetl volcano, the two most active and dangerous volcanoes in the country. The joint index of connectivity (ICJ) and lateral hydrological efficiency index (LHEI) were calculated for both volcanic areas in basins recently affected by eruptive activity (Volcán de Colima) and co-seismic landslides (Popocatépetl). The analyses enabled the identification of eleven recently activated sub-basins (3.82 km2) at the Volcán de Colima and fifteen (3.77 km2) at the Popocatepetl volcano, as a consequence of natural processes and economic activities. Critical thresholds indicating the percentage area of land cover/use at which a sub-basin reaches high or very high LHEI values and the percentage of land cover/use change required for a sub-basin to modify its behavior (activation-deactivation) were identified using classification trees. The holistic capacity of the concepts of connectivity and hydrological efficiency permits analyzing the spatiotemporal variations of sediment transport based on the interactions between the hydrogeomorphological dynamics of volcanic processes and the territorial impact of socio-economical activities. Through this approach, new active areas have been identified in both volcanoes; the knowledge of the processes that occurred in these areas represents a key factor for hazard and risk assessment for the population in the near future.

Investigations on chemical composition and natural radioactivity levels from salt water and peloid used in pelotherapy from the Techirghiol Lake, Romania.

The work presents the historical evolution, objectives, goals, concepts, chemical and radiometric methods, results and conclusions for salt waters and natural peloids used in pelotherapy. This study assesses chemical composition, natural radioactivity concentrations and the radiological hazard in peloid and salt water samples, from ten places in the Techirghiol Lake from Romania. Pelotherapy is a very important procedure, and thus, the materials used for this purpose must be well characterized to guaranty safety use. Concentrations of elements such as Sr, Ba, Mn, Fe, Sb, Zn, Cu, Pb, Ti, Ni, Cr, As have been measured using ICP-OES analytical technique. The natural radionuclides such as 238U, 226Ra, 232Th and 40K have been determined by gamma-ray spectrometry. The average activity concentrations were of 0.48 ± 0.10 Bq/kg for 238U, 0.60 ± 0.10 Bq/kg for 226Ra, 0.30 ± 0.08 Bq/kg for 232Th and 17.5 ± 1.3 Bq/kg for 40K for salt water samples. Also, the mean activity concentrations for peloids were: 5.70 ± 1.00 Bq/kg for 238U, 6.85 ± 1.60 Bq/kg for 232Th, 15.3 ± 3.7 Bq/kg for 226Ra and 95.8 ± 5.5 Bq/kg for 40K. The results from this study contribute to the identification of possible contaminants in the salt water and peloid, and their association with the potential ecological and human health risk. In this context, of using salt water and peloid in a relatively long treatment period, several radiological indices have been calculated, to determine if the radionuclide's content can be also harmful to human health. The assessment indicates that humans are not exposed to concentrations of metal contaminants higher than the international recommended values.

Ash clouds temperature estimation. Implication on dilute and concentrated PDCs coupling and topography confinement.

Pyroclastic density currents (PDCs) are among the most hazardous of all volcanic processes in terms of high speeds and unpredictable extent. While concentrated PDCs are usually topographically confined, the dilute counterpart (ash cloud) is able to overrun topographic barriers, with unexpected trajectories posing a high risk for human settlements around the volcano. Here, for the first time, the temperature of an ash could, for a PDC originated during the 11 July, 2015 Volcán de Colima eruption, is determined, without pre-installed instruments, based on the degree of charcoaling of trees affected by the ash cloud. Temperature estimations were performed using Reflectance analysis and microtomography images processing of pine wood charred fragments. The combination of these two independent and well-established methods to organic matter charred in a volcanic environment constitutes a pioneering attempt for the indirect temperature estimation of dilute pyroclastic density currents (PDCs). Charcoal fragments were sampled at different heights along tree trunks outstanding from the PDC deposit. Both the temperatures obtained from charcoal analyses (reflectance and microtomography) and observation of damages to the tree trunks allowed to distinguish: (i) a lower Zone A, which extends 150-180 cm above the top of the PDC deposit, where trunks show peeled bark and multiple lithic impacts; temperature values are equal or slightly higher than the underlying deposit for the entire length of the valley; (ii) an upper Zone B, developed above 150-180 cm from the top of the PDC deposit, where trees are only burned without any block impact marks; temperature estimations for Zone B are comparable with the PDC deposit temperature range from proximal to distal areas. The temperature data indicate that the 11 July, 2015 Colima PDC event, the ash cloud was always thermally coupled with the under-running concentrated flow for the entire length of the ravine, explaining the observed strong vertical uplift of the ash cloud and the substantial absence of ash cloud detachments along flow. A corollary of our study is that, should a detachment have occurred, the ash cloud surge would have had initial temperatures as high as the one carried by the high concentration part of the PDC. A major outcome of our study is that the temperature estimation of ash clouds bears important implication in terms of hazard assessment for pyroclastic density currents along narrow valleys that usually cut the steep slopes of stratovolcanoes.

Infant botulism due to C. butyricum type E toxin: a novel environmental association with pet terrapins.

We describe two cases of infant botulism due to Clostridium butyricum producing botulinum type E neurotoxin (BoNT/E) and a previously unreported environmental source. The infants presented at age 11 days with poor feeding and lethargy, hypotonia, dilated pupils and absent reflexes. Faecal samples were positive for C. butyricum BoNT/E. The infants recovered after treatment including botulism immune globulin intravenous (BIG-IV). C. butyricum BoNT/E was isolated from water from tanks housing pet 'yellow-bellied' terrapins (Trachemys scripta scripta): in case A the terrapins were in the infant's home; in case B a relative fed the terrapin prior to holding and feeding the infant when both visited another relative. C. butyricum isolates from the infants and the respective terrapin tank waters were indistinguishable by molecular typing. Review of a case of C. butyricum BoNT/E botulism in the UK found that there was a pet terrapin where the infant was living. It is concluded that the C. butyricum-producing BoNT type E in these cases of infant botulism most likely originated from pet terrapins. These findings reinforce public health advice that reptiles, including terrapins, are not suitable pets for children aged <5 years, and highlight the importance of hand washing after handling these pets.

[Insufficient correction of blood bicarbonate levels in biguanide lactic acidosis treated with CVVH and bicarbonate replacement fluids]. / Insufficiente correzione della bicarbonatemia nella acidosi lattica da biguanidi trattata con CVVH e liquido di reinfusione con bicarbonato.

BACKGROUND: In the course of Continuous Veno-Venous Hemofiltration (CVVH), bicarbonate buffer instead of lactate is suitable for the treatment of combined renal and hepatic failure and for patients suffering from lactic acidosis, type A or B, joined with acute renal failure (ARF). METHODS: We applied the CVVH buffered with bicarbonate for the treatment of two patients affected by ARF and severe lactic acidosis type B (due to biguanide intoxication) and we evaluated its ability to correct the acid-base balance. RESULTS: Clinical and laboratory data show that this technique, performed in standard conditions (plasma flow: 70 ml/min, ultrafiltration: 25 ml/min, bicarbonate concentration in the infusion fluid: 30 mEq/L), was inadequate to compensate for the high requirement of bicarbonate (approximately 280 mEq/hr during the first 6 hours of observation) and the severe metabolic acidosis, thus additional bicarbonate infusion was needed. CONCLUSIONS: In particular, from ascertained data and theoretical considerations, in the course of lactic acidosis caused by biguanide, in order to correct acidosis a positive balance of bicarbonate could be obtained only by means of a bicarbonate-based replacement fluid and of a continuous high flow hemofiltration, such as to assure an ultrafiltrate volume exceeding 150 ml/min.

[Radon levels in interiors in Valtellina, on the Angera hills and in the high valley of the Cervo river]. / Livelli di randon nelle abitazioni nella Valtellina, sulle colline di Angera e nell'alta valle del fiume Cervo.

The results are reported of an investigation carried out from 1988 to 1990 in many houses in various sites in Lombardy and Piedmont. Measurements were actually carried out in Valtellina, in Angera--on the Lombard side of lake Maggiore--and in the high valley of the river Cervo, north of Biella. The patterns of radon immission in houses due to buildings materials and also to soil emissions are described. Average values of radon levels were obtained using track-etch detectors, whereas fluctuations were recorded daily with a unit capable of detecting alpha particles in real time. Some of the values obtained in 28 Valtellina towns were quite high--e.g., about 1,000 Bq/m3 in towns along the Insubrica fault. The area around Bormio and the Masino valley did not exhibit high radioactivity levels. A total number of nearly 100 houses were investigated in Angera; the highest radon concentrations were observed in cellars and especially in the areas where fractures are bigger and more diffuse. One particular house was accurately examined with real-time analysis of radon fluctuations. Four small towns in the pluton area were investigated in the valley of the river Cervo. In this instance, values were generally high (mean concentration: 842 Bq/m3); the highest concentrations were found in cellars and in ground-floor rooms.

Assay of anti-cancer drugs in tissue culture: relationship of relapse free interval (RFI) and in vitro chemosensitivity in patients with malignant cerebral glioma.

One hundred and seventeen patients with cerebral glioma (Kernohan grades III and IV) were treated with adjuvant chemotherapy using procarbazine (PCB), CCNU and vincristine (VCR) following whole head irradiation. Cell cultures were prepared from 40 patients in this series and their sensitivity to each cytotoxic drug was assessed in a mictotitration assay with 35 S-methionine incorporation as the end point. Twenty-two of forty (55%) patients responded to PCB and/or CCNU in vitro, and sensitivity to these drugs was linked with increased RFI, whilst sensitivity to VCR was not. The RFI of patients who had responded to PCB or CCNU in vitro was significantly longer than the RFI of patients whose tumours failed to respond in vitro or patients who had not been tested. There was no difference in sex ratio, extent of operation, radiation dose and degree of steroid cover between responders, non-responders and untested groups. Grade III tumours tended to be more sensitive in vitro than grade IV tumours. The age of patients also influenced in vitro chemosensitivity. Patients with chemosensitive tumours in vitro tended to be younger than patients with insensitive tumours in vitro. Further statistical analysis, taking into account these prognostic factors, indicated an association between chemosensitivity in vitro and RFI.

Beta-cell function assessed by plasma C-peptide evaluation in diabetic thalassaemic patients.

In order to investigate the pancreatic function in patients with thalassaemia major, plasma glucose and immunoreactive C-peptide levels were determined in 9 diabetic thalassaemic patients and in 7 controls after arginine infusion. Mean basal and peak values and C-peptide areas in thalassaemic patients did not differ significantly from those of the controls. However, in the thalassaemic group there was a greater variation in values, since pancreatic beta-cell function was found either normal, reduced or increased. These findings could suggest that different factors may lead to diabetes which complicates thalassaemia, i.e. insulin-resistance, probably due to liver damage subsequent to iron deposition and infectious hepatitis, and insulinopenia, probably due to beta-cell lesion following iron storage in the pancreas.

Early iron overload in beta-thalassaemia major: when to start chelation therapy?

Twenty-eight children with beta-thalassaemia major aged between 11 and 48 months were given intensive transfusions. Serum iron, transferrin saturation, serum ferritin, non-transferrin iron, and subcutaneous desferrioxamine-induced urinary iron excretion were measured. The results showed that even children with a limited number of transfusions had severe iron overload as indicated, in particular, by the raised serum ferritin levels and the high excretion rates after subcutaneous infusion of desferrioxamine. The desferrioxamine test was useful, even in very young children, in assessing response to chelation therapy thus enabling such treatment to be started early to prevent harm from iron overload.

Haemoglobin levels and blood requirement in thalassaemia.

The relationship between blood requirement and the mean level of maintained haemoglobin was examined in 392 patients with homozygous beta-thalassaemia. Pre- and post-transfusional haemoglobin levels and the amounts of blood transfused were measured during a 1-year period. No significant differences were noted in the blood requirements of patients (splenectomised or not) irrespective of the haemoglobin level. It may be supposed that if the mean haemoglobin level is high the haematopoietic activity is inhibited, and hence the bone marrow mass and total blood volume are reduced. High haemoglobin levels may thus be obtained with no increase in blood intake.

Hypothalamic-pituitary function following successful treatment of intracranial tumours.

Hypothalamic-pituitary function was examined in seventeen patients treated in the past for extrasellar intracranial tumours. All patients had received a course of external cranial irradiation. Biochemical abnormalities of endocrine function were present in almost all of the patients. In particular, the growth hormone response to insulin induced hypoglycaemic stress was impaired in eleven out of fifteen patients. Preliminary data from a group of seven patients with intracranial tumours prior to radiotherapy are also presented. The possibility that cranial irradiation causes hypothalamic-pituitary dysfunction is discussed. The results suggest that endocrine assessment should be considered in patients who have been treated for intracranial tumours, even in the absence of direct pituitary involvement.

Dermatoglyphic studies in patients with Cooley's anemia and Cooley's trait.

The dermatoglyphic analysis of a group of Italiam patients with Cooley's anemia and Cooley's trait shows Cooley's anemia patients to undergo a significant increase of loops on fingers and a corresponding decrease of whorls. The total loops frequency correlates negatively with the ridge distribution per loop and the total ridge count is significantly decreased. The atd angles are larger. Minor changes in the distribution of patterns in the thenar and hypothenar areas are also observed. In the Cooley's trait patients, loops on fingers are more frequent than in controls, but no difference with Cooley's anemia series is observed. The above findings suggest that the gene(s) controlling loops formation in linkage disequilibrium with thalassemia mutant may have been favourably selected on the "thalassemia chromosome" in the malaria environment.

Leucocyte morphology and chromosome morphology.

The banding techniques currently employed in human cytogenetics for the identification of the individual chromosomes have been used to stain PHA lymphocytes and circulating leucocytes. The capacity of these techniques to localize singular chromosomes or chromosomal regions has been investigated. It has been observed that among the four major categories of bands (Q, G, E and R) only the quinacrine staining is informative in interphase nuclei, because of its peculiarity to stain the long arm of the Y chromosome and few other heterochromatic regions. Interphase nuclei treated according to the C-bands show the presence of several heterochromatic masses, corresponding to the centromeric areas of individual chromosomes, but as such they cannot be recognized accurately. More specific and selective techniques, like G-11 and G-Y protocols, appear to be suitable to localize the centromeric regions of chromosome no. 9 and and long arm of Y chromosome. Variation of the incubation time in the alkali-saline solutions and of pH values have proven to be appropriate for the demonstration of other heterochromatic regions in interphase nuclei and in circulating leucocytes. The "nuclear" approach to study of specific heterochromatic regions of human chromosomes may be of practical interest into the investigation of several biological problems and into the detection of individuals carrying chromosome variants.