The origins of the fight against rabies: a journey between the history of neuroscience and university museum collections.

Although rabies, or hydrophobia, is one of the so-called forgotten tropical diseases, it still kills thousands of people each year, especially children living in rural areas of Asia and Africa. This terrible disease was once a much-feared threat throughout Europe, whose terrifying symptoms were described in a vast body of literature that was based on both science and popular beliefs. One notable individual whose name is linked to the fight against this disease is Adelchi Negri, a brilliant but unfortunate pupil of Camillo Golgi. At the beginning of the 20th century, Negri observed peculiar formations in the brains of infected animals: known as Negri's bodies, these formations became an important diagnostic tool used in anti-rabies institutes all over the world.

Extensive study on physicochemical properties of polychlorinated biphenyls in a commercial ion trap mass spectrometer, relevance in analytical and environmental chemistry.

Polychlorinated biphenyls (PCBs) exist as 209 congeners, consisting of biphenyl molecules, where the number and substitution positions of halogen atoms are known to affect industrial uses, environmental transport mechanisms, distribution, fate, and toxicity. The complexity of the problem requires accurate physicochemical studies of an increasing number of congeners in order to understand the environmental and biological processes at play. This work presents a systematic study on the thermodynamic and kinetic properties of PCBs by quadrupole ion trap mass spectrometry. A clear relationship between structure and behavior of PCBs in mass spectrometry experiments has been observed. Overall data demonstrate that di-ortho congeners show lower thermodynamic stability and higher fragmentation rate than non/mono-ortho. Congeners follow different fragmentation mechanisms according to the number of chlorine atoms in ortho position of the biphenyl system. Experimental kinetic curves of mono/non-ortho and di-ortho congeners show a strong similarity with classical first-order kinetics curves; in particular, di-ortho congeners follow a first-order consecutive reaction, while mono/non-ortho follow a first-order parallel reaction. For each studied congener, the kinetic constant of reaction (fragmentation) has been determined. Data support environmental levels and biochemical transformations described in literature. The general picture of the PCB behavior inside a quadrupole ion trap provides the basis for the development of reliable and cost-effective analytical methods to the determination of ultra-low level trace of PCB congeners.

A comprehensive approach to actual polychlorinated biphenyls environmental contamination.

Worldwide polychlorinated biphenyls (PCBs) pollution is due to complex mixtures with high number of congeners, making the determination of total PCBs in the environment an open challenge. Because the bulk of PCBs production was made of Aroclor mixtures, this analysis is usually faced by the empirical mixture identification via visual inspection of the chromatogram. However, the identification reliability is questionable, as patterns in real samples are strongly affected by the frequent occurrence of more than one mixture. Our approach is based on the determination of a limited number of congeners chosen to enable objective criteria for Aroclor identification, summing up the advantages of congener-specific analysis with the ones of total PCBs determination. A quantitative relationship is established between congeners and any single mixture, or mixtures combination, leading to the identification of the actual contamination composition. The approach, due to its generality, allows the use of different sets of congeners and any technical mixture, including the non-Aroclor ones. The results confirm that PCB environmental pollution in northern Italy is based on Aroclor. Our methodology represents an important tool to understand the source and fate of the PCBs contamination.

Short communication: staff dose reduction during coronary angiography using low framing speed.

Radiation exposure of cardiac catheterization laboratory staff is a known occupational hazard, and efforts are made to obtain dose levels which are "as low as reasonably achievable". This study assessed the reduction in staff radiation exposure using cine framing at 12.5 f s-1 during coronary cineangiography, instead of 25 f s-1. Thermoluminescent dosemeters were used to measure equivalent dose at several sites for the operator, nurse assistant, and X-ray technician during 15 procedures at both frame rates. Patient-related and procedure-related variables were similar in the two groups of examinations. Mean equivalent dose absorbed (microSv) at the left side of the forehead was reduced by 61%, 60% and 36%, for the operator, nurse assistant and X-ray technician, respectively. With use of the lower frame rate similar reductions by 42%, 62% and 62% were measured at the thyroid level, and by 51%, 40% and 61% at the mid-thorax level. Cinefilming at low frame rates during coronary arteriography allows a substantial X-ray dose reduction at all body sites for all staff. Use of lower frame rates wherever possible is of special interest since it may also reduce patient radiation exposure.

[Radiologic practice and radioprotection in Italian hemodynamic laboratories]. / Pratica radiologica e radioprotezione nei laboratori di emodinamica italiani.

Increasing numbers of diagnostic and therapeutic cardiac catheterization procedures are performed in Italy each year. Radiation exposure of the cardiac catheterization laboratory staff is a known hazard, and there is growing public and professional concern over the risks of low-energy medical ionizing radiation for the patients. The aim of this study was to outline the range of current radiological and radiation protection practice in large-volume cardiac catheterization laboratories in Italy. In August 1994 a questionnaire was submitted to the chief invasive cardiologist of the 32 cardiac catheterization laboratories nation-wide having performed at least 1000 procedures in 1993. All laboratories responded. There were variations in both the radiologic technique (cine framing speed, mean film lengths and fluoroscopy times) and the radiation protection practice (use of shields, leaded collars and glasses, and sites where dosimeters are worn). In 22 of 32 laboratories the cardiologists were not aware of radiation exposure data, and only 6 laboratories could quote the exposure provided by their X-ray system or estimates of the dose absorbed by patients during diagnostic or therapeutic procedures. The results of this survey indicate that radiological practice, and techniques for measuring and reducing exposure of the personnel vary widely in cardiac catheterization laboratories in Italy. These data suggest also that reducing patients' radiation exposure is not, in general, considered to be a quality assurance priority by interventional cardiologists.

Dental trauma in children and adolescents in Valparaiso, Chile.

This study analyzed traumatic injuries in the primary and permanent dentition in children treated from 1990 to 1992 at the Children's Dental Traumatology Service in Valparaiso, Chile. A total of 227 records from patients 2 to 21 years old was studied with regard to the cause of injury, location of injury, time elapsed before treatment, history of previous trauma, type of injury, number of injured teeth, and how patients seek treatment. A total of 73 patients had injuries to the primary dentition (pD) and 154 to the permanent dentition (PD) with a total of 357 injured teeth (115 primary, 242 permanent). Ten to 12-year-old children had the highest number of injuries (33%). Falling was the most common cause of injury in both groups (82% pD, 58% PD), followed by striking against objects (13% pD, 19% PD) and bicycle accidents (9% PD). Most injuries in children with primary dentition (68%) occurred at home, while children with permanent dentition had most accidents at school (38%). Most children (61%) sought treatment after 24 h (52% pD, 65% PD), 61 children had suffered previous trauma (36% pD, 23% PD). The most common injuries in primary teeth were luxation (26%), intrusion (21%) and subluxation (18%). Uncomplicated crown fracture (34%), followed by complicated crown fracture (21%), were the main injuries in permanent teeth. There was no difference in the number of teeth involved for either dentition. A single tooth injury was found in 54%. Two teeth were involved in 35%, and three or more teeth in 11%.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of adenylate cyclase-coupled beta-adrenergic receptors in the developing mammalian palate.

A direct radioligand binding technique utilizing a beta-adrenergic antagonist [3H]Dihydroalprenolol [( 3H]DHA) was employed in the identification and characterization of fetal palatal beta-adrenergic receptors. [3H]DHA binding was saturable (Bmax 16 fmol/mg protein) with high affinity and an apparent equilibrium dissociation constant (KD) of 1.5 nM. Binding of [3H]DHA was displaced by the competitive beta-adrenergic antagonist propranolol in a concentration-dependent manner. Dissociation kinetic studies demonstrated almost complete reversibility of radioligand binding within 60 min. The functionality of these beta-adrenergic receptors was demonstrated by showing that fetal palatal mesenchymal cells responded to catecholamine agonists with dose-dependent accumulations of intracellular cAMP. This effect could be entirely blocked by the beta-antagonist, propranolol. The relative potency order of catecholamines in eliciting an elevation of cellular cAMP was characteristic of a beta 2-adrenergic receptor-mediated response: (-) isoproterenol greater than (-) epinephrine greater than (-) norepinephrine. In addition, this response was found to be stereospecific with (-) isoproterenol being significantly more potent than (+) isoproterenol. Both the [3H]DHA binding characteristics and the catecholamine sensitivity of fetal palatal tissue support the presence of adenylate cyclase-coupled beta-adrenergic receptors in the developing mammalian secondary palate.

Role of cyclic AMP, prostaglandins, and catecholamines during normal palate development.

The biochemical regulatory mechanisms controlling palatal differentiation are largely unknown. Published data suggest that hormonally regulated levels of cyclic AMP may be important in normal, as well as abnormal, development of the secondary palate. Palatal cAMP, prostaglandins, and catecholamines appear to be integrally involved in cellular differentiation during normal palatal development. Studies such as those outlined in this chapter are fundamental to meaningful investigations probing the etiology of abnormal development. Questions dealing with biochemical mechanisms of action of potential cleft palate teratogens, or with genetically based orofacial malformations, must be grounded on a thorough understanding of biochemical events and regulation of these events during normal craniofacial development. Evidence suggests that cyclic AMP levels, possibly regulated by prostaglandin and/or catecholamine receptor occupancy, may play an important role in normal growth and differentiation of the developing orofacial region and may serve as metabolic foci for teratogenic perturbation resulting in palatal clefting.