The phytoremediation of an organic and inorganic polluted soil: A real scale experience.

A phytoremediation process with horse manure, plants (Populus alba, Cytisus scoparius, Paulownia tomentosa) and naturally growing vegetation was carried out at a real-scale in order to phytoremediate and functionally recover a soil contaminated by metals (Zn, Pb, Cd, Ni, Cu, Cr), hydrocarbons (TPH) and polychlorobiphenyls (PCB). All the plants were effective in two years in the reclamation of the polluted soil, showing an average reduction of about 35%, 40%, and 70% in metals, TPH and PCB content, respectively. As regards the plants, the poplar contributed the most to organic removal. In fact, its ability to take up and detoxify organic pollutants is well known. Paulownia tomentosa, instead, showed high metal removal. The Cytisus scoparius was the least effective plant in soil decontamination. The recovery of soil functionality was followed by enzyme activities, expressing the biochemical processes underway, and nutrient content useful for plant growth and development. Throughout the area, an enhancement of metabolic processes and soil chemical quality was observed. All the enzymatic activities showed a general increase over time (until 3-4 fold than the initial value for urease and ß-glucosidase). Moreover, Cytisus scoparius, even though it showed a lower decontamination capability, was the most effective in soil metabolic stimulation.

Soil physical changes and plant availability of Zn and Pb in a treatability test of phytostabilization.

A treatability test of phytostabilization was carried out on two soils sampled downstream a mining Italian area with Lolium italicum and Festuca arundinacea. Beside chemical content of Pb and Zn in aerial parts and in roots, also some physical parameters were determined at the end of the growth cycle of plants. Particle size distribution was analysed with a laser granulometer while cracking patterns and porosity were determined by means of image analysis. Compost, used at two rates (10%, and 30% v/v) in order to improve soil physical characteristics, always raised biomass with similar effects for both doses. The concentration of Pb and Zn in aerial parts and in roots of L. italicum and F. arundinacea decreased more than five times in presence of compost. A general lack of clear effects of both plants on soil physical parameters was noticed. Formation of more water stable aggregates, a rise of the area occupied by cracks, and new porosity formed by elongated and irregular pores were found in soil samples treated with compost.

Neural substrates of memory, affective functions, and conscious experience.

This review presents an account of the areas and circuits of the brain that are thought to be involved in such cognitive functions as memory, affect and consciousness. Considerable progress has been made in the past two decades in the identification of the cerebral areas and in our understanding of the brain mechanisms involved in these functions, thanks in large parts to a number of imaging observations (PET and fMRI), together with many clinical neurological and experimental studies. Thus, there is now convincing evidence that these high level functions are represented in a complex organization of interconnected cortical and subcortical areas that operate as spatially distributed systems, specialized for the different cognitive activities. Despite the progress that has been made, it is still not known how genetic and environmental factors interact during early development and throughout life to create the necessary conditions out of which these cognitive capacities emerge, nor is it evident to what extent they are shaped by adaptive changes in synaptic organization and other forms of neuronal plasticity.

RT-nested PCR for the detection of enterovirus in biological samples from patients with suspected enteroviral infections

In this study, we have tested a reverse transcription (RT) nested polymerase chain reaction (nPCR) for detection of enterovirus (EV) RNA in cerebrospinal fluid (CSF), serum samples, and conjunctival swabs (CS) from patients with suspected enterovirus infections. A specific 113-bp fragment was amplified using primers designed based on 5' non coding region of the enterovirus genome. The enterovirus RT-nPCR was able to detect 0.001 plaque forming unit (pfu)/ml. Since no PCR product was detected in each of the CSF, CS and serum samples from patients with proven-non-enterovirus viral infections, this method was found to be specific. EV RNA was detected in all 30 culture-confirmed CSF samples and yielded positive results in 5 out of 7 additional cases of culture-negative CSF samples with other evidences of enterovirus infection. Overall, EV RNA was detected in 95 of the patients with clinical diagnosis of viral central nervous system (CNS) disease and confirmed enterovirus infection. Furthermore, we were able to detect EV RNA in 24 (47) out of 51 CSF samples from patients with clinical diagnosis of viral CNS disease and negative laboratory evidence of viral infection. The percentage of positive EV RNA detection in paired CSF and serum samples from 11 patients with an enterovirus isolate in CSF was 100 (11 of 11) and 73 (8 of 11), respectively. In addition, EV-specific IgM was detected in 64 (7 of 11) of the sera tested. The method was also tested against 136 samples of CS from patients with clinical diagnosis of acute hemorrhagic conjunctivitis. Ninety nine of them resulted positive (73), while only 27 (20) had been positive for viral culture. In summary, our study shows the importance of enterovirus RT-nPCR for the diagnosis of enterovirus associated disease in different kind of biological samples and different types of diseases.

[Diagnosis of tuberculosis in children in provinces of Argentina]. / Diagnóstico de la tuberculosis infantil en provincias de la Argentina.

Confirming the diagnosis of pediatric tuberculosis is cumbersome, due to the clinical features (generally paucibacillary forms) of the disease. This national study was undertaken in order to establish: the features of childhood tuberculosis at the time of diagnosis, the criteria on which the pediatricians based the diagnosis, the bacteriologic contribution to the diagnosis and the quality of notifications to the National Programme. Medical and laboratory records were reviewed for children under 15 years of age who were diagnosed with tuberculosis disease or primary infection during 1995. The study included children cared for at health centres from Argentinean provinces (capital city excluded) where pediatricians accepted to participate. Four hundred cases (17% of childhood notifications to the National Programme) and 81 primary infections were studied. The percentage of children studied by means of chest radiology, presence of symptoms, Mantoux test, case contact investigation and bacteriology were 95.3%, 79.6%, 90.1%, 92.7% and 35% for pulmonary cases, respectively, and 87.7%, 100%, 87.7%, 85.9% and 78.9% for extra-pulmonary cases, respectively. Of the evaluated pulmonary cases, 99.1% had abnormal x-rays, 79.0% had a tuberculin test > or = 10 mm, 79.8% had symptoms and 80.2% had a history of close contact. All extra-pulmonary patients had symptoms at the time of diagnosis; 63.0% had abnormal chest radiograph at diagnosis. Bacteriologic confirmation was achieved in 10.7% of the cases (20.8% and 40.0% of the investigated pulmonary and extra-pulmonary cases, respectively). This study would indicate that the diagnosis is made at relatively early stages of the disease. In general, recommendations of the Argentine Society of Pediatrics were followed. A low rate of bacteriological proof of diagnosis was observed, probably due to the scarce bacteriologic investigation and the low yield achieved in culturing pulmonary specimens. The study found under-register of cases and lack of precision in the information reaching the National Programme.

Nested PCR for rapid detection of mumps virus in cerebrospinal fluid from patients with neurological diseases.

In this study, we have developed a reverse transcription (RT)-nested polymerase chain reaction (n-PCR) for the detection of mumps virus RNA in cerebrospinal fluid (CSF) from patients with neurological infections. A specific 112-bp fragment was amplified by this method with primers from the nucleoprotein of the mumps virus genome. The mumps virus RT-n-PCR was capable of detecting 0.001 PFU/ml and 0.005 50% tissue culture infective dose/ml. This method was found to be specific, since no PCR product was detected in each of the CSF samples from patients with proven non-mumps virus-related meningitis or encephalitis. Mumps virus RNA was detected in all 18 CSF samples confirmed by culture to be infected with mumps virus. Positive PCR results were obtained for the CSF of 26 of 28 patients that were positive for signs of mumps virus infection (i.e., cultivable virus from urine or oropharyngeal samples or positivity for anti-mumps virus immunoglobulin M) but without cultivable virus in their CSF. Overall, mumps virus RNA was detected in CSF of 96% of the patients with a clinical diagnosis of viral central nervous system (CNS) disease and confirmed mumps virus infection, while mumps virus was isolated in CSF of only 39% of the patients. Furthermore, in a retrospective study, we were able to detect mumps virus RNA in 25 of 55 (46%) CSF samples from patients with a clinical diagnosis of viral CNS disease and negative laboratory evidence of viral infection including mumps virus infection. The 25 patients represent 12% of the 236 patients who had a clinical diagnosis of viral CNS infections and whose CSF was examined at our laboratory for a 2-year period. The findings confirm the importance of mumps virus as a causative agent of CNS infections in countries with low vaccine coverage rates. In summary, our study demonstrates the usefulness of the mumps virus RT-n-PCR for the diagnosis of mumps virus CNS disease and suggests that this assay may soon become the "gold standard" test for the diagnosis of mumps virus CNS infection.

RT-nested PCR for the detection of enterovirus in biological samples from patients with suspected enteroviral infections.

In this study, we have tested a reverse transcription (RT) nested polymerase chain reaction (nPCR) for detection of enterovirus (EV) RNA in cerebrospinal fluid (CSF), serum samples, and conjunctival swabs (CS) from patients with suspected enterovirus infections. A specific 113-bp fragment was amplified using primers designed based on 5' non coding region of the enterovirus genome. The enterovirus RT-nPCR was able to detect 0.001 plaque forming unit (pfu)/ml. Since no PCR product was detected in each of the CSF, CS and serum samples from patients with proven-non-enterovirus viral infections, this method was found to be specific. EV RNA was detected in all 30 culture-confirmed CSF samples and yielded positive results in 5 out of 7 additional cases of culture-negative CSF samples with other evidences of enterovirus infection. Overall, EV RNA was detected in 95% of the patients with clinical diagnosis of viral central nervous system (CNS) disease and confirmed enterovirus infection. Furthermore, we were able to detect EV RNA in 24 (47%) out of 51 CSF samples from patients with clinical diagnosis of viral CNS disease and negative laboratory evidence of viral infection. The percentage of positive EV RNA detection in paired CSF and serum samples from 11 patients with an enterovirus isolate in CSF was 100% (11 of 11) and 73% (8 of 11), respectively. In addition, EV-specific IgM was detected in 64% (7 of 11) of the sera tested. The method was also tested against 136 samples of CS from patients with clinical diagnosis of acute hemorrhagic conjunctivitis. Ninety nine of them resulted positive (73%), while only 27 (20%) had been positive for viral culture. In summary, our study shows the importance of enterovirus RT-nPCR for the diagnosis of enterovirus associated disease in different kind of biological samples and different types of diseases.

[Nontuberculous mycobacteria in patients with cystic fibrosis]. / Microbacterias no tuberculosas en pacientes con fibrosis quistica.

The prevalence of nontuberculous mycobacteria (NTM) isolated from the lower airways of adult cystic fibrosis (CF) patients appears to be increasing. Different centers of USA, England, Sweden and Ireland have reported a prevalence ranging from 1.5 to 19.5%. The aim of the present study was to investigate the presence of NTM in patients assisted at these centers. A total of 92 sputum specimens and/or gastric contents from 40 CF patients were studied. Ages of patients ranged from 4 months to 25 years. Samples were obtained during acute exacerbation or in routine check-up. Mycobacterium avium-intracellulare complex strains were isolated from six patients with moderate or severe clinical manifestations. Five of these patients were considered as being colonized by NTM. Active mycobacterial disease was diagnosed in one patient and he underwent treatment. The index of bacterial contamination of cultures was very high early along the study (57%), decreasing to 2.8% later due to a change in the methodology used in the processing of samples. It was concluded that the presence of NTM is relatively frequent in patients with CF, even in children with moderate or severe compromise, a fact which strongly suggests that NTM should be systematically searched for considering the possibility that the patients might develop active disease.

Increased prevalence of genotype F hepatitis B virus isolates in Buenos Aires, Argentina.

The genomic coding region of the hepatitis B surface antigen (HBsAg) was partially sequenced from 12 HBsAg-positive sera of carriers residing in Buenos Aires, Argentina. A phylogenetic analysis groups the 12 isolates into genotypes A (n = 4), B (n = 1), D (n = 2), and F (n = 5). The occurrence of genotypes A and D is not unexpected, considering the mainly European origin of the studied population. The high prevalence of genotype F and its genetic composition support the suggestion that F strains originated in native populations of the New World.

Mechanisms of stereopsis in monkey visual cortex.

A substantial proportion of neurons in the striate and prestriate cortex of monkeys have stereoscopic properties; that is, they respond differentially to binocular stimuli that are known in humans to provide cues for stereoscopic depth perception. Stereoscopic neurons, as these cells may be called, are selective for horizontal positional disparity (i.e., display disparity selectivity) and for the textural correlation between images over their receptive fields (i.e., they show correlation selectivity). Many neurons have tuned disparity response profiles that collectively cover the entire range of physiological disparities. Neurons with peak responses at or about the zero disparity ("tuned zero neurons," excitatory or inhibitory) have narrow and symmetrical profiles. Neurons that are tuned to larger disparities, either crossed ("tuned near neurons") or uncrossed ("tuned far neurons"), have broader excitatory profiles that are asymmetrically wider toward the smaller disparities, and commonly include an inhibitory component about the zero disparity. Other stereoscopic neurons have reciprocal profiles ("near" or "far" neurons, respectively) in the sense that they respond with excitation to crossed or uncrossed disparities, and with suppression to disparities of opposite sign. Stereoscopic neurons can also signal the textural correlation between paired retinal images by giving different responses to random-dot patterns that have, and to those that do not have, the same dot distribution over the neuron's left and right receptive fields. Tuned-zero excitatory neurons characteristically respond to uncorrelation with suppression; tuned-zero inhibitory neurons, with excitation; and both types give the opposite responses to correlated stereopatterns. Neurons selective for nonzero disparities, both tuned and reciprocal, also give excitatory responses to uncorrelated stimuli, but these responses are smaller and more variable than those evoked by correlated patterns at the effective disparities. These findings suggest that stereoscopic neurons in the visual cortex of the macaque comprise three operational systems: (1) a zero-disparity system that is involved in fine depth discrimination with the obligatory singleness of vision, and the maintenance of vergence; and (2) a near-, and (3) a far-disparity system that together signal qualitative estimates of depth with double vision, and vergence responses to large disparities.

Detección y caracterización de mutantes pre-core del virus de la hepatitis B (HBV) en pacientes cronicamente infectados / Detection and characterization of precore mutant of hepatitis B virus (HBV) in chronically infected patients

La infección por el virurs de la Hepatitis B (HBV) es causa importante de morbi-mortalidad en el mundo, hallándose asociada con afecciones hepáticas graves tales como cirrosis y/o carcinoma hepatocelular primario (HCC). Entre los diversos factores que influyen en la severidad del daño hepático pueden señalarse, la emergencia de mutantes pre-core (HBeAg defectuosa), la heterogeneidad genética del virus y del hospedador y la competencia del sistema inmune. En particular la presencia de mutantes pre-core en portadores crónicos se asocia, además, con una baja respuesta a la terapia con interferón alfa. En este trabajo presentamos evidencias de la presencia de dichas mutantes en pacientes cronicamente infectados HBeAg negativos (HB Agi positivo) en la Argentina. Al suero de estos pacientes se les extrajo el ADN viral que fue amplificado por PCR y caracterizado por análisis con enzimas de restricción. Finalmente uno de estos sueros fue secuenciado en la región pre-core evidenciando la presencia de mutaciones en los codones 15 y 28 de dicha región característicos de estas mutantes

[Transient hyperglycemia in acute myocardial infarct: the short- and long-term risk factor for mortality]. / Iperglicemia transitoria nell'infarto miocardico acuto: fattore di rischio per la mortalità a breve e lungo termine.

To evaluate the prevalence and prognostic significance of hyperglycemia in acute myocardial infarction, we studied 700 patients (mean age 63.3 +/- 10.97) subsequently admitted to the UCIC of Tradate Hospital during the period January 1976 to December 1987. Patients were followed up for a median period of four years. On the basis of fasting blood glycaemia values in the first five days of hospitalization, excluding the admission day, patients were divided into groups: 401 patients (57.0%) with constantly normal glycaemia; 84 patients (12.0%) with glycaemia equal or superior to 120 mg/100 ml, and with subsequent normalization; and 215 patients (31.0%) with diabetes mellitus diagnosed before hospitalization and/or with persistent hyperglycaemia. The overall mortality was 284 (40.5%) and cardiovascular deaths were 90.8%. Within the first month of myocardial infarction 98 patients died. The mortality rate was 9.4% in normoglycaemic patients and 20.2% in transient hyperglycaemic patients, similar to the value observed in diabetic patients (20.0%). During the follow-up 186 patients died. Late mortality after the first month is higher in diabetic patients (40%) and patients with transient hyperglycaemia (37%) compared to normoglycaemic patients (25.3%). Multivariate analysis shows that independent predictive variables are: for mortality in the first month, Killip class only; and after the first month, Killip class, metabolic classification, sex and supraventricular arrhythmias. The present study shows that transient hyperglycaemia has a low prevalence in the first days of acute myocardial infarction. Transient hyperglycaemia could be attributed not only to increased sympathetic tone elicited by acute myocardial infarction, but is probably a pathologic condition with an adverse outcome to which multiple factors contribute.

Adaptation of the Reitboeck method of multiple microelectrode recording to the neocortex of the waking monkey.

We adapted to the neocortex of waking monkeys a method for multiple microelectrode recording devised by Reitboeck. A sliding platform allows micropositioning of 7 electrodes independently, in 2 microns steps. Microelectrodes are quartz glass filaments (80 microns o.d.) with central metal cores (30 microns) of tungsten-platinum alloy. Filaments are drawn in a high temperature chamber, and ground to the desired form and tip size. The microdrive is held over the region to be explored, and the microelectrodes passed through 300 microns o.d. guide tubes fixed in implant thimbles of chosen size an and x - y arrangement of tubes, sealed by an O-ring into a small craniotomy opening. A microprocessor controlled recording system provides gain, noise and wave-shape filtering, impedance testing, and differential amplitude discrimination for each channel. Electrode movement is obtained via the microprocessor which displays and updates on the console terminal the electrode depth, impedance, and the channel assignment of each electrode. A second microprocessor based system is used to collect, buffer, and encode in real time all event data, which are transferred whenever convenient to a minicomputer that controls the experiment. Exploratory recordings were made in the posterior parietal, somatic sensory, and motor cortical areas. The system has now been used successfully in a number of investigations.

Influences of uniform and textured backgrounds on the impulse activity of neurons in area V1 of the alert macaque.

The influences of the visual background on the spontaneous and evoked activity of neurons in the striate cortex (V1) of the awake and behaving macaque were investigated using uniform (dark and bright) and textured (dynamic random-dot) large fields (10 degrees) centered on the receptive field of the cell under study. Rhesus monkeys were trained to fixate a small target while visual patterns were presented on monitor displays and the impulse activity of single cortical neurons recorded extracellularly with metal microelectrodes. The discharge rates of the ongoing, spontaneous activity of the vast majority of V1 neurons, as well as their responses to optimally adjusted bar stimuli, were not significantly influenced by the luminance of a uniform background. On the other hand, the activity of more than 50% of V1 neurons was clearly affected by a textured background. Comparison of the effects of a uniformly dark background and a background of dynamic random dots showed that the neuron's spontaneous discharge rate was typically higher in the presence of the textured background, while the evoked response was often reduced in amplitude or even suppressed. The opposite effects were observed in only a few neurons. These findings indicate that neurons in area V1 are highly sensitive to a textured background of dynamic random dots which exert on them an activating effect, chiefly by stimulation of the neuron's receptive field, with consequent increase in the ongoing discharge and a reduction of the dynamic range of impulse activity, leading to a reduction in the amplitude of the response evoked by a contrast stimulus.

[Dilated cardiomyopathy in infants. Report of a clinical case with particularly favorable outcome]. / Cardiomiopatia dilatativa nel lattante. Descrizione di un caso clinico ad evoluzione particolarmente favorevole.

Dilated cardiomyopathy has a poor prognosis in infants and children. We report the favourable long term outcome of a case of dilated cardiomyopathy discovered at age seven months. The knowledge of natural history of these patients is very important to develop predictive indexes to select patients who might respond to medical management and those who might be suitable candidates for cardiac transplantation.

Dynamic stabilization of receptive fields of cortical neurons (VI) during fixation of gaze in the macaque.

The positions of receptive field borders of striate cortical neurons were measured repeatedly in awake monkeys during attentive fixation of a small target. The border position, as marked by the onset of evoked activity in response to a moving stimulus, did not show the variability expected from previous measures of eye position variability during fixation. Measured variability was smaller than expected. Trial-by-trial comparisons suggest that receptive field borders are not shifted by the small eye movements occurring during attentive fixation. It is our hypothesis that attentive fixation engages a mechanism that gates incoming information to achieve a stabilization of the receptive field relative to the external world. Such a dynamic positional compensation may underlie preliminary evidence showing that the response of stereo-sensitive neurons in striate cortex is consistent with stimulus disparity measures and, within limits, does not reflect the retinal disparities produced by the changes in binocular alignment during fixation.

Stereoscopic mechanisms in monkey visual cortex: binocular correlation and disparity selectivity.

The neural signals in visual cortex associated with positional disparity and contrast texture correlation of binocular images are the subject of this study. We have analyzed the effects of stereoscopically presented luminous bars and of dynamic random-dot patterns on the activity of single neurons in cortical visual areas V1, V2, and V3-V3A of the alert, visually trained rhesus macaque. The interpretation of the results and considerations of possible neural mechanisms led us to recognize 2 functional sets of stereoscopic neurons. (1) A set of neurons, tuned excitatory (T0) or tuned inhibitory (TI), which respond sharply to images of zero or near-zero disparity. Objects at or about the horopter drive the T0 neurons and suppress the TI, while objects nearer and farther have the opposite effects on each type, inhibition of the T0 and excitation of the TI. The activity of these neurons may provide, in a reciprocal way, the definition of the plane of fixation, and the basic reference for binocular single vision and depth discrimination. (2) A second set of neurons includes tuned excitatory at larger crossed or uncrossed disparities (TN/TF) and neurons with reciprocal excitatory and inhibitory disparity sensitivity with cross-over at the horopter (NE/FA). Binocularly uncorrelated image contrast drives these neurons to a maintained level of activity, which shifts, in response to correlated images, toward facilitation or suppression as a function of positional disparity. These neurons may operate in the neural processing leading to stereopsis, both coarse and fine, and also provide signals for the system controlling binocular vergence. These results indicate that cortical visual neurons are binocularly linked to respond to the relative position and contrast of the images over their receptive fields, and also that both these aspects of binocular stimulation may be utilized by the brain as a source of stereoscopic information.