Evidence-based care and the case for intuition and tacit knowledge in clinical assessment and decision making in mental health nursing practice: an empirical contribution to the debate.

This paper provides empirical evidence that challenges the view that methods of clinical assessment and decision making should not rely solely on logical positivist approaches. Whilst the National Health Service (NHS) Executive currently takes a hard positivist line on what constitutes evidence-based practice, data reveal that it is not always appropriate to disregard the tacit knowledge and intuition of experienced practitioners when making assessment decisions in mental health nursing practice. Data support the case for a holistic approach which may draw on intuition and tacit knowledge, as well as traditional approaches, to meet the requirements of clients with complex mental health problems. A model based on Schon's notion of reflection in and reflection on practice is proposed which demonstrates the value of intuition and tacit knowledge. This model allows the generation of insights which may ultimately be demonstrated to be acceptable and empirically testable. It is accepted that an element of risk taking is inevitable, but the inclusion of a formal analytical process into the model reduces the likelihood of inappropriate care interventions. The cognitive processes which experienced nurses use to make clinical decisions and their implications for practice will be explored.

Effect of polymer foam morphology and density on kinetics of in vitro controlled release of isoniazid from compressed foam matrices.

The purpose of this study was to compare the effect of polymer foam morphology and density prior to compaction on the kinetics of isoniazid (INH) release from the final high-density extruded matrices. The feasibility of preparing low density foams of several biopolymers, including poly(L-lactide) (PLLA), poly(glycolide) (PGA), poly(DL-lactide-co-glycolide) (PLGA), poly(gamma-benzyl-L-glutamate) (PBLG), and poly(propylene fumarate) (PPF), via a lyophilization technique was investigated. Low-density foams of PLGA, PBLG, and a mixture of PLGA and PPF were successfully fabricated by lyophilization of the frozen polymer solutions either in glacial acetic acid or in benzene. The morphology of these foams depends on the polymer as well as the solvent used in the fabrication process. Thus, PLGA produces a capillary structure when lyophilized from benzene solution and a leaflet structure from glacial acetic acid, but PBLG yields a leaflet structure from benzene. Matrices were prepared by impregnating these foams with aqueous solutions of INH, removing the water by a second lyophilization, and then compressing the low-density INH containing foams by compaction and high-pressure extrusion. The resulting nonporous matrices had densities of approximately 1.30 g/cm3. In vitro kinetics were in accord with the Roseman-Higuchi diffusion model and demonstrate that release rates depend on the initial foam density, while foam structure has little influence on the release kinetics.

Mechanisms of isoniazid release from poly(d,l-lactide-co-glycolide) matrices prepared by dry-mixing and low density polymeric foam methods.

The release mechanisms of a small molecular drug from biodegradable poly(d,l-lactide-co-glycolide) (PLGA) cylindrical matrices were investigated. Isoniazid (INH), one of the most effective drugs against tuberculosis (TB), was selected as the model drug. Controlled-release matrices consisting of the drug and polymer were fabricated by two methods. The first of these, the dry-mixing method, involved the extrusion of a mixture of micronized drug and polymer particles as rods. In the second technique, the low density polymeric foam method, drug particles were enclosed in the cells of porous polymeric foams prior to extrusion. In vitro, the dry-mixed matrices released INH more rapidly than the polymeric foam matrices. The Roseman-Higuchi diffusion model, which had previously been found to be effective in analyzing the release kinetics of INH from the dry-mixed matrices, also fit the kinetics of INH released from matrices prepared from polymeric foams. This indicated that the release was still diffusion-controlled rather than degradation-controlled. The release mechanisms were further investigated, and two diffusion mechanisms, pore diffusion and lattice diffusion, were proposed for the INH controlled-release matrices according to the way in which they were prepared. Matrices prepared by the dry-mixing method appear to segregate drug particles along polymer grain boundaries and thus have a pore diffusion mechanism, while matrices prepared by the foam method entrap drug within the porous structure of foams and thus display a lattice diffusion mechanism. Theoretically, these two diffusion mechanisms can be identified by their activation energies for diffusion. With varying in vitro temperature, the activation energies were calculated from plots of ln (DIT) vs T-1 and in D vs T-1, where D is the diffusivity and T is the in vitro temperature in K. According to the results, we concluded that the INH from the dry-mixed matrices diffused through the drug channels filled with the medium, while the INH from the foam matrices diffused through the polymer lattice.

Analysis of a vinyl pyrrolidone/poly(propylene fumarate) resorbable bone cement.

A resorbable bone cement was formulated from N-vinyl-2-pyrrolidinone (VP), the unsaturated polyester poly(propylene fumarate) (PPF), and the inorganic filler tribasic calcium phosphate (hydroxy apatite). Cure, initiated by benzoyl peroxide and accelerated by N,N-dimethyl-p-toluidine, resulted in the formation of VP crosslinks between polyester chains. During cure the cement hardened from a viscous moldable putty to a rigid structure with a shore D hardness of 50-60. The purpose of this study was to determine the fractions of PPF and VP incorporated into the crosslinked structure. Dissolution of the cured cement in water followed by extraction of the residue in tetrahydrofuran indicated that over 90% of the PPF was crosslinked over the range of PPF/VP ratios explored, but that the fraction of VP used in formation of crosslinks depended linearly on the PPF/VP ratio. Kinetic analysis of these data suggests that k'pp/kpf (the reactivity ratio) was approximately 2.0 where k'pp is the rate constant for the addition of VP radical to VP monomer leading to formation of poly(vinyl pyrrolidone), and kpf is for the addition of VP radical to PPF unsaturation.

Managing the care of patients with mental retardation: a survey of physicians.

A questionnaire regarding the clinical management of patients with mental retardation living in the community was mailed to a 50% random sample of physicians practicing in Maine; the response rate was 56%. Almost 80% of respondents reported that they were currently providing care to patients with mental retardation. Survey results identified the major issues confronting physicians treating such patients and quantitatively assessed their importance from the physicians' perspective. Inadequate medical information was identified as the greatest obstacle to patient care. Physicians' ratings of the utility of specific measures designed to lessen these obstacles were presented. Generally, continuing education was viewed as less useful than practice support measures.

Cloning and expression of the carbon monoxide dehydrogenase genes from Pseudomonas thermocarboxydovorans strain C2.

Carbon monoxide dehydrogenase (CODH) from Pseudomonas thermocarboxydovorans strain C2 is composed of three non-identical subunits. A gene library of C2 DNA in lambda vector L47.1 was generated and screened using anti-CODH serum. Western blotting experiments revealed a protein which co-migrated with and had the same immunological reaction as the large subunit of CODH in some of the clones isolated from the library. The coding region was pinpointed to a 4 kb fragment which was subcloned into plasmid. Western blotting experiments showed that all three subunits of CODH were coded for by the subclone. However, no CODH activity was detected.

Adaptation of body temperature and nociception to cold stress in preweanling rats.

In order to investigate the response of rat pups to stress, 10-day-old rats (N = 10) were exposed to cold water (14 degrees C) for 5 min or to a control treatment (N = 10) for 5 consecutive days. On the sixth day when the rats were 15 days of age, all rat pups were immersed in cold water for 5 min. Body temperature and nociceptive threshold were recorded as functional indexes of the stress response to cold water. Results revealed that the rat pups that had been previously exposed to the cold stressor demonstrated a smaller decline in body temperature and a smaller increase in nociceptive threshold following cold-water immersion than rat pups which had no prior experience with the stressor. Thus, as measured by thermoregulatory and nociceptive function, 15-day-old rat pups are capable of adapting to repeated stressful experiences.

Family interaction and adolescent suicidal behaviour: a preliminary investigation.

While investigators have emphasized the importance of familial relations in the production of suicidal behaviour in adolescence, experimental evaluation of specific family interaction processes has, thus far, been neglected. The aim of the present study was to investigate possible relationships between adolescent suicidal behaviour and total on-going family functioning. Hypotheses were advanced to evaluate the communication, interaction and reinforcement patterns in families. A modified revealed differences technique was employed to elicit standardized segments of interaction which were video-taped and later studied by two independent raters. The sample consisted of twelve individually matched, intact family tetrads, six normal (N) and six containing an adolescent female who had exhibited suicidal behaviour (SM). Results suggest that SM families constitute a malfunctioning system which can be differentiated from that of normal samples. As compared with the N group, SM family interaction evidenced less effective productivity, specificity, and adaptive interaction, and higher rates of conflict and negative reinforcement. Overall findings were discussed in terms of current family theory and their possible relationship to the genesis, maintenance and management of some classes of suicidal behaviour.