TWO NEW SINGLE-EXPOSURE, MULTI-DETECTOR NEUTRON SPECTROMETERS FOR RADIATION PROTECTION APPLICATIONS IN WORKPLACE MONITORING

This communication describes two new instruments, based on multiple active thermal neutron detectors arranged within a single moderator, that permit to unfold the neutron spectrum (from thermal to hundreds of MeV) and to determine the corresponding integral quantities with only one exposure. This makes them especially advantageous for neutron field characterisation and workplace monitoring in neutron-producing facilities. One of the devices has spherical geometry and nearly isotropic response, the other one has cylindrical symmetry and it is only sensitive to neutrons incident along the cylinder axis. In both cases, active detectors have been specifically developed looking for the criteria of miniaturisation, high sensitivity, linear response and good photon rejection. The calculated response matrix has been validated by experimental irradiations in neutron reference fields with a global uncertainty of 3%. The measurements performed in realistic neutron fields permitted to determine the neutron spectra and the integral quantities, in particular H*(10).

Transmission of Grapevine virus A and Grapevine leafroll-associated virus 1 and 3 by Heliococcus bohemicus (Hemiptera: Pseudococcidae) Nymphs From Plants With Mixed Infections

Mealybugs (Hemiptera: Pseudococcidae) represent a serious threat for viticulture as vectors of phloem-restricted viruses associated with the grapevine rugose wood and leafroll diseases. Heliococcus bohemicus (Šulc) is known to be involved in the spread of these two viral diseases, being a vector of the Grapevine virus A (GVA) and the Grapevine leafroll-associated virus 1 and 3 (GLRaV-1 and GLRaV-3). This study investigated the acquisition and transmission efficiency of H. bohemicus fed on mixed-infected plants. Nymphs were field-collected onto GVA, GLRaV-1, and GLRaV-3 multiple-infected grapevines in two vineyards in North-Western Italy, and were used in transmission experiments under controlled conditions. Even if most of the collected nymphs were positive to at least one virus, transmission occurred only to a low number of test grapevines. The transmission frequency of GLRaV-3 was the highest, whereas GVA was transmitted to few test plants. The transmission of multiple viruses occurred at low rates, and nymphs that acquired all the three viruses then failed to transmit them together. Statistical analyses showed that the three viruses were independently acquired and transmitted by H. bohemicus and neither synergistic nor antagonistic interactions occurred among them. GVA and GLRaVs transmission efficiencies by H. bohemicus were lower than those reported for other mealybug vectors. This finding is consistent with the slow spread of leafroll and rugose wood diseases observed in Northern Italy, where H. bohemicus is the predominant vector species.

Electronic nose and isotope ratio mass spectrometry in combination with chemometrics for the characterization of the geographical origin of Italian sweet cherries

Sweet cherries from two Italian regions, Apulia and Emilia Romagna, were analysed using electronic nose (EN) and isotope ratio mass spectrometry (IRMS), with the aim of distinguishing them according to their geographic origin. The data were elaborated by statistical techniques, examining the EN and IRMS datasets both separately and in combination. Preliminary exploratory overviews were performed and then linear discriminant analyses (LDA) were used for classification. Regarding EN, different approaches for variable selection were tested, and the most suitable strategies were highlighted. The LDA classification results were expressed in terms of recognition and prediction abilities and it was found that both EN and IRMS performed well, with IRMS showing better cross-validated prediction ability (91.0%); the EN-IRMS combination gave slightly better results (92.3%). In order to validate the final results, the models were tested using an external set of samples with excellent results.

Instrumental and multivariate statistical analyses for the characterisation of the geographical origin of Apulian virgin olive oils

In this paper, virgin olive oils (VOOs) coming from three different geographic origins of Apulia, were analysed for free acidity, peroxide value, spectrophotometric indexes, chlorophyll content, sterol, fatty acid, and triacylglycerol compositions. In order to predict the geographical origin of VOOs, different multivariate approaches were applied. By performing principal component analysis (PCA) a modest natural grouping of the VOOs was observed on the basis of their origin, and consequently three supervised techniques, i.e., general discriminant analysis (GDA), partial least squares-discriminant analysis (PLS-DA) and soft independent modelling of class analogy (SIMCA) were used and the results were compared. In particular, the best prediction ability was produced by applying GDA (average prediction ability of 82.5%), even if interesting results were obtained also by applying the other two classification techniques, i.e., 77.2% and 75.5% for PLS-DA and SIMCA, respectively.

Geographical origin and breed discrimination of Apulian lamb meat samples by means of analytical and spectroscopic determinations

With the aim of finding parameters capable of characterizing meat according to geographical origin, twenty-five lamb meat samples from three areas located in Apulia (Southern Italy) were analysed for moisture, ash, fat and protein content, stable isotope ratios ((15)N/(14)N and (13)C/(12)C), major elements (Ca, Mg, Na, K) and trace metals (Zn, Cu, Fe, Cr). (1)H high resolution magic angle spinning (HR-MAS) NMR spectra were also obtained for all the samples. The advantages of the (1)H HR-MAS NMR technique are that sample preparation is easy, since the spectrum is obtained directly on the minced solid sample, and that information is acquired for a large number of metabolites (amino acids, fatty acids, sugars, etc.). The application of multivariate statistical analysis to two data sets containing tissue composition results together with the metals contents and (1)H HR-MAS NMR spectral data together with isotope ratios, respectively, provided in both cases a satisfactory origin differentiation of lamb meat samples.

Interpretation of a complex picture and its sensitivity to frontal damage: a reappraisal

A. R. Luria introduced the interpretation of a meaningful picture as a tool for assessing pre-frontal impairment. We gave this test to 196 normal adults, who were asked to communicate what was happening in the portrayed scene (a boy chases a mouse hidden under a cupboard, while three frightened girls assist). The same subjects were given two other frontal tests (verbal fluency on phonemic cue and Trail Making Test (TMT)) and Raven's Matrices. Twenty-three normal subjects (12%) failed to correctly interpret the picture. We also examined 20 patients whose brain lesion encroached upon pre-frontal areas, in order to check if this version of the test could be easily administered to this type of patient, and if its difficulty level was appropriate for avoiding ceiling and floor effects. Twelve patients were unable to interpret the picture (60%). A similar failure rate was observed with the same subjects on verbal fluency and TMT, while Raven's Matrices were less impaired (35%). Some dissociation was found between Picture Interpretation and the TMT. The Italian version of the Picture Interpretation Test is suitable for the examination of pre-frontal patients.

SNOM and AFM microscopy techniques to study the effect of non-ionizing radiation on the morphological and biochemical properties of human keratinocytes cell line (HaCaT)

In this study we have employed atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM) techniques to study the effect of the interaction between human keratinocytes (HaCaT) and electromagnetic fields at low frequency. HaCaT cells were exposed to a sinusoidal magnetic field at a density of 50 Hz, 1 mT. AFM analysis revealed modification in shape and morphology in exposed cells with an increase in the areas of adhesion between cells. This latter finding was confirmed by SNOM indirect immunofluorescence analysis performed with a fluorescent antibody against the adhesion marker beta4 integrin, which revealed an increase of beta4 integrin segregation in the cell membrane of 50-Hz exposed cells, suggesting that a higher percentage of these cells shows a modified pattern of this adhesion marker.

Effectiveness of treatments for major depression in primary medical care practice: a post hoc analysis of outcomes for African American and white patients

OBJECTIVE

To retrospectively determine whether race differentially influences treatment adherence and clinical outcomes among 68 African Americans and 92 whites treated for major depression in four urban, primary care settings.

METHOD

Study participants were randomly assigned to standardized interpersonal psychotherapy or pharmacotherapy with nortriptyline, and were assessed at baseline, and successive time points up to 8 months for severity of depression, and mental and physical health-related functioning.

RESULTS

Intent-to-treat analyses revealed no treatment or race-specific differences in symptomatic recovery when both groups were provided standardized psychotherapy or pharmacotherapy. However, African Americans had poorer functional outcomes than whites.

CONCLUSIONS

African American and white primary medical care patients are effectively treated with standardized psychotherapy and pharmacotherapy. Future research should assess the impact of cultural context on symptom presentation, psychosocial functioning, and treatment adherence and response.

[Tension-free hernioplasty. Our experience]

BACKGROUND

In recent years the "tension-free" techniques have been progressively replacing conventional hernioplasty by Bassini and Shouldice. Personal experience in the application of various techniques using a prosthesis to make the back wall of the inguinal canal stronger is described.

METHODS

From January 1995 to February 1996, 119 non-selected patients were examined; they were operated by Trabucco's (100 cases), Lichtenstein's (16 cases), Gilbert's (13 cases) and Rives's (1 case) techniques, using polypropylene prostheses. Patients were followed for ten months (range 4-18) after surgery with Day-hospital checks at 1 month, 4 months, 1 year and 18 months.

RESULTS

Mortality was not observed. Morbility presented in 12 cases: 2 suppurating wounds, 3 seromas, 2 hematomas, 2 temporary neuralgias of the genito-femoral nerve and 2 scrotal edemas. There was a recurrence (0.8%).

CONCLUSIONS

The cases presented confirm the validity of the "tension-free" techniques, both for reduced incidence of complications and recurrences, and for a better compliance of the patient, compared with conventional techniques.

[Laparoscopic cholecystectomy. Personal experience]

The authors present their experience (136 cases) in the treatment of cholelithiasis with coelioscopic cholecystecomy. After a comparison of this modern technique with the traditional laparotomic approach, they underline the several advantages of coelioscopy (short hospitalization and early return to patient's work, reduced post-operative abdominal pain, avoidance of laparocele, better aesthetic results). Then the authors describe the present treatment of combined cholecysto-choledochic lithiasis with the help fo ERCP (their hope is for further improvement in surgical instruments to allow a single laparoscopic solutions.

[Gastric leiomyosarcoma. Three clinical cases in emergency]

The authors describe three cases of gastric leiomyosarcoma that required surgical treatment in emergency. Myogenic gastric tumors are extremely rare (1-3% of primitive gastric neoplasias) and little is known about their biological evolution, even if they seem to have scarce power of spreading and of local invasion. Echoendoscopy appears to be the best screening method for the evaluation of staging and DT (doubling time). In the authors' opinion, when neoplasms have a diameter less than 5 cm, subtotal or total gastrectomies don't offer better results in the follow-up than simple minimal excision of the gastric tumor.

[Acute abdomen caused by eosinophilic gastritis]

The authors describe a case of acute abdomen operated in emergency for obstruction in a patient with eosinophilic gastritis. This is very unusual pathology characterized by eosinophilic infiltration of the gastric antral wall combined with peripheric eosinophilia. This particular case was operated for a small bowel obstruction but in those rare cases, when we can reach a diagnosis with endoscopic biopsy, a prudential attitude becomes inevitable as this pathology is very responsive to medical treatment with corticosteroids.

Effect of covalent labeling of dextran-benzenehexacarboxylate on hemoglobin

The covalent fixation of benzenehexacarboxylate (BHC) onto dextran was carried out according to several reaction schemes. The polyanionic polymers thus synthesized were capable of decreasing the oxygen affinity of hemoglobin by specifically interacting with the 2,3-diphosphoglycerate (2,3-DPG) binding site of the protein. The intensity of this effect was correlated to both the chemical structure of the polyanionic polymers and the BHC content in polymer. The polyanionic polymer, containing 0.035 mol BHC/g and presenting no cross-linking between its polymer chains, possessed the best effector properties. These properties were used to direct the covalent fixation of the dextran-benzenehexacarboxylate onto the phosphate binding site of the protein. The resulting hemoglobin was mainly substituted at the same time by one or more linked BHC onto both alpha beta dimers in the vicinity of the 2,3-DPG site. Thus, the modification of hemoglobin led to an increase in the hydrodynamic volume of each dimer sufficient to limit the diffusion of the conjugates through the kidney membrane, even if the conjugates had dissociated into alpha beta dimers. Compared to that of free hemoglobin, the oxygen affinity of the conjugates was significantly decreased. This type of covalent conjugate exhibited general properties quite suitable for use as blood substitutes.

Effects of intensive lipid-lowering therapy on the coronary arteries of asymptomatic subjects with elevated apolipoprotein B

BACKGROUND

Do the benefits of intensive lipid-lowering therapy seen in symptomatic patients extend to high-risk subjects who have never had symptoms?

METHODS AND RESULTS

Of 120 men completing the FATS trial, 91 were symptomatic and 29 asymptomatic. All had apolipoprotein B > or = 125 mg/dL, a positive family history, and coronary atherosclerosis. All were counseled in diet and randomized to intensive therapy: colestipol 10 g TID plus either niacin 1 g QID or lovastatin 20 mg BID or to conventional therapy: placebos, or colestipol if low-density lipoprotein cholesterol was elevated. End points included quantitative arteriographic disease change and clinical events over a 2.5-year interval. At baseline, symptomatic and asymptomatic patients had comparable risk profiles, but proximal stenosis severity averaged 36% for symptomatic and 23% for asymptomatic patients (P < .001). Among the 91 symptomatic patients, those in the intensive group experienced definite (> or = 10%S) proximal lesion progression less frequently than conventional (24% of intensive versus 48% of conventional) and definite regression more frequently (36% of intensive versus 15% of conventional) (P = .009). Similarly, among the 29 asymptomatic patients, 19% of intensive versus 38% of conventional had progression and 31% of intensive versus 0% of conventional, regression (P = .04). Ischemia on baseline exercise tolerance testing was associated with significantly greater proximal disease progression among the asymptomatic patients. Clinical cardiovascular events (death, infarction, or revascularization) occurred in 10 of 38 symptomatic patients originally assigned to conventional therapy, compared with 5 of 76 symptomatic patients assigned to intensive (P < .01); no asymptomatic patient had an event.

CONCLUSIONS

Asymptomatic subjects with this high-risk profile have less coronary disease at baseline than comparable symptomatic patients, and they have an excellent short-term clinical prognosis. However, asymptomatic subjects are indistinguishable from symptomatic patients in terms of their arterial disease progression with conventional therapy and their regression with intensive. These findings may justify an active treatment strategy in such subjects, particularly those with provokable ischemia.

[Splenectomy versus splenic salvage. Our experience]

The authors describe their experience in the surgical treatment of splenic lesions, mostly traumatic. In recent years a resolutely conservative attitude has been turned to splenic salvage, thanks to late findings on its immunological and haematological functions. Against 59 splenectomies for III-V degree lesions, the authors report a case of splenic trauma (II degree) without surgical treatment, monitored with clinical, haematological and instrumental (echography) test.

[Intestinal occlusion caused by internal hernia of the retrocaecal recess. Description of a case]

The authors describe an acute intestinal occlusion due to a rare case of strangulated intra-abdominal hernia of the retrocaecal peritoneal recess. They underline the rarity of this pathology which is often treated in emergency without any possibility of preoperative diagnosis. Therefore, in order to carry out surgical therapy with good results, a correct knowledge of the anatomical features of these hernias is necessary.

A maximum confidence approach for measuring progression and regression of coronary artery disease in clinical trials

BACKGROUND

Imaging trials using arteriography have been shown to be effective alternatives to clinical end point studies of atherosclerotic vascular disease progression and the effect of therapy on it. However, lack of consensus on what end point measures constitute meaningful change presents a problem for quantitative coronary arteriographic (QCA) approaches. Furthermore, standardized approaches to QCA studies have yet to be established. To address these issues, two different arteriographic approaches were compared in a clinical trial, and the degree of concordance between disease change measured by these two approaches and clinical outcomes was assessed.

METHODS AND RESULTS

In the Familial Atherosclerosis Treatment Study (FATS) of three different lipid-lowering strategies in 120 patients, disease progression/regression was assessed by two arteriographic approaches: QCA and a semiquantitative visual approach (SQ-VIS). Lesions classified with SQ-VIS as "not," "possibly," or "definitely" changed were measured by QCA to change by 10% stenosis in 0.3%, 11%, and 81% of cases, respectively. The "best" measured value for distinguishing definite from no change was identified as 9.3% stenosis by logistic regression analysis. The primary outcome analysis of the FATS trial, using a continuous variable estimate of percent stenosis change, gave almost the same favorable result whether by QCA or SQ-VIS.

CONCLUSIONS

The excellent agreement between these two fundamentally different methods of disease change assessment and the concordance between disease change and clinical outcomes greatly strengthens confidence both in these measurement techniques and in the overall findings of the study. These observations have important implications for the design of clinical trials with arteriographic end points.

Effect of dextran benzene polycarboxylates on the functional properties of human hemoglobin

The present study deals with the fixation of benzene polycarboxylates such as benzene hexacarboxylate (BHC) or benzene tetracarboxylate (BTC) onto dextran, with the aim of obtaining polyanionic polymers capable of decreasing the oxygen affinity of Hb by interacting with its phosphate binding site. The synthesis was carried out according to several reaction schemes. The polyanionic polymers presented the strongest effector properties, when the polyanionic molecule (BHC or BTC) were directly fixed onto the hydroxyl functions of dextran in the presence of a carbodiimide or by means of the benzene tetracarboxylic anhydride. The introduction of a spacer arm between the polymer and the polyanionic molecule led to the formation of crosslinking between chains of dextran. Among the synthesized polymers those which possess effector properties similar to those of 2,3-diphosphoglycerate (2,3-DPG) were bound onto oxyHb. The resulting covalent conjugates exhibited a low oxygen affinity and a molecular size quite fitted to a potential use as blood substitutes.

Covalent fixation of hemoglobin to dextran phosphates decreases its oxygen affinity

The interactions between various dextran phosphates and Hb (hemoglobin) were studied by measuring the oxygen-binding parameters of the mixtures. The effector properties of polymers were found to depend on the concentration of monoalkylmonophosphate groups on the polymers and also on their molecular weights. The covalent fixation of dextran phosphates bearing aldehydic groups to oxyHb and deoxyHb was carried out. The oxygen-binding properties of the conjugates thus obtained depended upon the initial form of the protein. Thus, only the conjugates synthesized from deoxyHb exhibited a low oxygen affinity, which means that, in this case, the linkages between the dextran phosphate and the protein allow a permanent interaction of the phosphate groups with amines of the 2,3-diphosphoglycerate binding site. The Hill coefficient values of these conjugates were smaller than that of free Hb, corresponding to a loss of the cooperativity of the protein upon fixation of polymers. However, as these new conjugates are capable of unloading more O2 than blood when subjected to oxygen pressures corresponding to physiological conditions, they can be regarded as potential erythrocyte substitutes.

Thromboembolic events in patients with malignant superior vena cava syndrome and the role of anticoagulation

In patients with superior vena caval obstruction resulting from malignancy, the importance of vena caval thrombosis and the role of anticoagulation are incompletely understood. The authors discuss this aspect of the management of 25 patients with malignant superior vena cava syndrome. Ten patients were retrospectively reviewed after having been clinically diagnosed without venography, and treated without anticoagulation. Five thromboembolic complications occurred, two of which proved fatal. Fifteen patients were prospectively evaluated by angiography and then treated with anticoagulants. Angiographic evidence of intraluminal subclavian vein or superior vena caval thrombosis was found in five of these patients, and no thromboembolic complications occurred. Of the 20 patients ultimately anticoagulated, two fatal intracranial hemorrhages developed. The authors suggest the need for randomized prospective trials if the role of venography and anticoagulation in this syndrome is to be determined.

Interaction of a macromolecular polyanion, dextran sulfate, with human hemoglobin

Interactions of dextran sulfate with amino groups of oxy- and deoxyhemoglobin were followed by both potentiometric measurements between pH 6 and 7.3 and oxygen-binding studies. The uptake of protons observed upon addition of dextran sulfate to hemoglobin shows that the interaction with the deoxy form is strong and that the main site is probably located in the phosphate-binding beta-cavity, whereas the interaction with the oxy form is more diffuse, probably with a great number of relatively weak binding sites. The influence of dextran sulfate on the oxygen dissociation curve of hemoglobin confirms these findings, as the effect of the polymer is to lower hemoglobin affinity for oxygen to a great extent, which proves that it stabilizes the deoxy form more strongly than the oxy one.

MR imaging of pediatric cerebral abnormalities

One hundred sixteen magnetic resonance (MR) imaging studies from 105 pediatric patients with a variety of cerebral abnormalities were reviewed to determine the diagnostic efficacy of MR in the pediatric population. All subjects tolerated the MR procedure well, although sedation was necessary for younger children. Compared with CT, MR proved to be advantageous in detection and characterization of the pathology in 23 of 105 patients, especially when the abnormality was located along the base of the brain and midline, or when it involved primarily the white matter. Intracranial calcification was the one abnormality not detected with MR although dense calcifications could be seen as areas of low signal intensity. Some characteristics of various pathological entities were compared in an attempt to differentiate among abnormalities in the same anatomical location: craniopharyngioma from optic chiasm and hypothalamic glioma, cystic glioma from arachnoid cyst, and chronic subdural hematoma from subdural hygroma. The lack of ionizing radiation in MR is of particular interest in pediatric neuroradiology since radiation is of special concern in the young age group.