Morphology of synthetic DOPA-eumelanin deposited on glass and mica substrates: an atomic force microscopy investigation.

Bright field microscopy and atomic force microscopy techniques are used to investigate morphological properties of synthetic eumelanin, obtained by oxidation of L-DOPA solution, deposited on glass and mica substrates. Deposits of eumelanin are characterized by aggregates with different shape and size. On a micrometric scale, filamentous as well as granular structures are present on glass and mica substrates, with a larger density on the former than on the latter. On a nanometric scale, filamentous aggregates, several microns long and about 100 nm wide and high, and granular aggregates, ∼50 nm high and 100 nm wide, are found on both substrates, whereas point-like deposits less than 10nm high and less than 50 nm wide are found on mica substrate. Dynamic light scattering measurements and atomic force microscopy images support the evidence that eumelanin presents only nanometric point-like aggregates in aqueous solution, whereas such nanoaggregates organize themselves according to granular and filamentous structures when deposition occurs, as a consequence of interactions with the substrate surface.

[Using atomic force microscopy to analyze morphological changes and mechanical properties caused by cellular exposure to low doses of pesticides]. / Utilizzo della microscopia a forza atomica per l'analisi di alterazioni morfologiche e meccaniche cellulari causate da esposizione a basse dosi di pesticidi.

A commercial pesticide is usually composed of active ingredients and formulants. Among the active ingredients, Deltamethrin is a pyrethroid chemical widely used for synthesizing pesticides products which are very effective in damaging the central nervous system of pests. In this work, we analyze, by means of atomic force microscopy (AFM), cellular morphological changes induced by exposure to a Deltamethrin-based commercial pesticide (Decaflow). AFM microscopy, in addition to the well-known characterization of the cellular topography, has the ability to monitor interesting biomechanical parameters of the surface as roughness and elastic modulus. In particular, we exposed normal human keratinocytes for 24 hours at different solutions of Decaflow, well below the threshold of cytotoxicity. The AFM images of exposed cells show alterations of surface cell shape. Moreover exposed cells are characterized by an increase of the value of membrane roughness. The mechanical properties of cells are also modified after Decaflow exposure, as confirmed by a decrease of the elasticity modulus with increasing the concentration of pesticide.

Founding friends: families and institution building in early 19th century Philadelphia.

BACKGROUND: Nurses have always had an interest in the relationships among families, clinicians, and healthcare institutions. This case study of the Friends Asylum for the Insane in early 19th century Philadelphia examines the historical roots of these relationships. METHODS: Data sources are archival documents about the male founders of the Friends Asylum, its constituent families, and the committees responsible for the creation and the maintenance of the institution. RESULTS: Families seeking a temporary respite from day-to-day turmoil created The Friends Asylum in Philadelphia. The Friends Asylum allowed them to continue to explore the processes that ultimately gained them an enduring identity as members of the newly emerging middle-class. DISCUSSION: These data suggest that the Asylum served individuals limited in their capacity for the self-control needed for a new kind of middle-class identity and those families vulnerable to the demands made by the roots of this new identity. For individuals, it provided a place that replicated the intimate domestic ideal. And for families, it allowed the sharing of care-taking responsibilities with kin who wanted the insane out of the home, but not out of the family. CONCLUSION: In the early 19th century, families presented clinicians not just with dilemmas, but with solutions that carried substantial cultural weight. This study suggests that theoretical innovations in healthcare might draw from the transformations in normative rules about domestic, work, and social roles. It suggests that nurses remain aware of the possibility that it may not be nurses who empower patients; it may be patients who empower nurses.

Enzyme conjugation to the polysaccharide chitosan: smart biocatalysts and biocatalytic hydrogels.

Laccase from Coriolopsis gallica was conjugated to the renewable biopolymer chitosan using carbodiimide chemistry. The laccase-chitosan conjugate was observed to offer three unique properties. First, the laccase-chitosan conjugate displayed pH-responsive behavior such that the conjugate was soluble and active under acidic conditions, but precipitated when the pH was raised toward neutrality. Second, the laccase-chitosan conjugate was more stable than free laccase at extreme pHs. At pH 1, the inactivation rate constant (k(in)) for the soluble laccase-chitosan conjugate was 20-fold less than that for free laccase. At pH 13, k(in) for the insoluble laccase-chitosan conjugate was nearly 3-fold less than that for free laccase. Finally, the laccase-chitosan conjugate could be cross-linked under mild conditions to create biocatalytic hydrogels. Potential benefits for enzyme-chitosan conjugates are discussed.

Surface diffusion coefficients for room acoustics: free-field measures.

A surface diffusion coefficient is needed in room acoustics to enable the quality of diffusing surfaces to be evaluated. It may also facilitate more accurate geometric room acoustic models. This paper concentrates on diffusion coefficients derived from free-field polar responses. An extensive set of two- and three-dimensional measurements and predictions was used to test the worth of different diffusion coefficient definitions. The merits and problems associated with these types of coefficients are discussed, and past parameters reviewed. Two new coefficients are described. The new measure based on the autocorrelation function is forwarded as the best free-field coefficient. The strengths and weaknesses of the coefficient are defined.

Virtual power: gendering the nurse-technology relationship.

To date, studies of the relationship between technology and its consumers have used the constructs of traditional paradigms of production and consumption as the foundation for analysis. These studies have served to reinforce traditional concepts of gender and hierarchy in the nursing-technology dichotomy. To propose a new and more relevant framework for analysing the technology-nursing relationship, the analysis of gender within the methodology of the social history of technology will be used. Healthcare will be viewed as a technologic network, and within that network multiple knowledge domains reside and interact. These domains, in turn, are socially constructed and historically contingent. This paper operationalizes this argument by examining the domain of the early nurse practitioner movement of the 1960s as part of a gendered technologic system. The findings of this study illuminate the agency of nurses in the shaping of traditionally male knowledge domains and as a crucial factor for understanding the evolution of not only the particularities of the nurse-technology relationship, but also the generalities of the gendered ways of knowing within the healthcare-technology relationship. Perhaps most importantly, different sets of questions can be formulated to analyse the history of the nurse practitioner movement from a technologic perspective that will provide new standpoints for the nursing-technology dichotomy in the millennium.

Toward a history of research in nursing.

The disciplinary focus of available overviews of the history of nursing research neglects how such analyses might illuminate the broader questions of what factors in the world of research in general and nursing research in particular frame the intellectual processes of disciplined curiosity, reasoned inquiry, and painstaking experimentation. Because it is precisely these broader questions that are of increasingly vital concern to the history both of nursing and of knowledge development, suggested here are ways in which the history of research in nursing might be positioned as a case study of the interplay between the social and the scientific in the generation of new data, new knowledge, and new considerations. To this end, interconnected examples of social context and gender are used to show how recasting nurses as critical actors in and interpreters of the world of science and research may well prove to be the historian's intellectual contribution to the profession's drive for sustained legitimation and authority.

Dihydroergocryptine in the treatment of Parkinson's disease.

In the last 20 years dopamine agonists have been considered more and more helpful as primary therapy for Parkinson's disease (PD). Recently the neuroprotective activity and the therapeutic efficacy of a new ergot derivative, alpha-dihydroergocryptine (DHEC), has been highlighted. In the present work we resume the experimental and clinical data reported about this drug. The rationale for dopamine (DA) agonists as primary therapy for Parkinson's disease (PD) is based on the possibility to delay the onset of long term I-dopa syndrome (LTS) (King, 1992); moreover DA agonists seem to exert a neuroprotective effect on substantia nigra neurons. In fact, they stimulate DA receptors bypassing the degenerating nigrostriatal neurons and their metabolic machinery (Lieberman, 1992; Olanow, 1992); more recently, some studies have shown that these drugs have a direct protective effect too (Felten et al., 1992; Yoshikawa et al., 1994). In this minireview we resume the data reported about neuroprotective activity and therapeutic efficacy of a new ergot derivative, alpha-dihydroergocryptine (DHEC).

Observation of growth steps, spiral dislocations and molecular packing on the surface of lysozyme crystals with the atomic force microscope.

The (110) faces of lysozyme crystals in their mother liquor have been investigated using an atomic force microscope (AFM) in height mode. Crystal growth and dissolution steps, as well as simultaneous growth and dissolution in pits, have been observed. Screw dislocations were also observed but the fine structure has not yet been investigated. Images that may possess molecular resolution were obtained and compared with theoretical images based on the crystallographic structure and the effects of arbitrary tip profiles. Crystallographic periodicities of 38 and 112 A were observed. A recurring feature is a centered periodic array of minima that may be associated with one of the two nearly planar sheets of molecules present in the crystal that are parallel to the (110) faces.

Apomorphine test in de novo Parkinson's disease.

We administered apomorphine, a powerful dopaminergic agonist, subcutaneously to 25 untreated patients with parkinsonian features and evaluated motor response with the aim of discriminating idiopathic Parkinson's disease (IPD) from multiple system atrophy and progressive supranuclear palsy. The response to apomorphine was strongly predictive of responsiveness to subsequent levodopa follow-up and of the final diagnosis, made on the basis of both clinical and instrumental evaluation. Our data confirm that the apomorphine test is helpful in the differential diagnosis of IPD.

[Diurnal worsening in Parkinson patients treated with levodopa]. / Peggioramento diurno in parkinsoniani trattati con levodopa.

Parkinson's disease (PD) patients show a good response to levodopa in the morning, and reduced duration or complete failure of response later in the day, but the pathophysiology of this phenomenon remains unclear. We evaluated motor performance hourly over a twelve-hour period in patients treated with levodopa/carbidopa (group A), with bromocriptine (group B), and in "de novo" patients (group C). At 8 am, 12 and 4 pm, group A patients received standard doses of levodopa/carbidopa, whereas patients of group B and C took, respectively, 5 mg bromocriptine and placebo. In "de novo" patients and in patients under bromocriptine we did not observe significant diurnal changes in motor score, whereas in patients under levodopa a progressive daytime worsening, which significantly correlated with progressive increase in 3-O-methyldopa plasma levels, was visible. These data seem to indicate a contributory role of pharmacokinetic or pharmacodynamic factors related to levodopa assumption, rather than to the underlying disease, in the afternoon worsening in PD.

Prognosis of Fallot's tetralogy after palliative operations: 10-25 year follow-up.

The condition of 350 patients with Fallot's tetralogy (FT) who had palliative surgery (aortopulmonary shunt or transventricular valvotomy) was reviewed 10-25 years later: 136 patients (38%) are alive without any further operation, 106 (30%) have recovered completely, and 108 (31%) have died. Actuarial survival at 25 years of the patients who had palliation was 50% compared to 83% for the group who subsequently had complete correction. After the first five years the mortality rates became 5% per year. Of the patients who were not reoperated upon, 33% felt that the quality of their life was normal, 40% were limited, and 27% were severely limited. The older the patient at palliative procedure, the better the clinical course and the longer the interval before another operation, if the latter was needed at all. Of the patients who had a Brock procedure, the survival rate at 25 years was 80% and the clinical condition was good in 72% of the patients who had not been reoperated upon. Comparison with the natural history of unoperated FT reported by others indicates that the palliative procedures prolonged life in our series; mortality continued at a steady rate for a few years after palliative surgery, probably as a function of the severity of the anatomical and functional abnormality, and independently of the age at which the palliative procedure was performed. Among the palliative procedures, the Brock operation was followed by the best results both in relieving symptoms and in prolonging life.