Neural feature abstraction from judgments of similarity

The common neural network modeling practice of representing the elements of a task domain in terms of a set of features lacks justification if the features are derived through some form of ad hoc preabstraction. By examining a featural similarity model related to established multidimensional scaling techniques, a neural network is developed that generates features from similarity data and attaches weights to these features. The network performs a constrained search of a continuous solution space to determine the features and uses a previously developed regularization technique to minimize the number of features it derives. The network is demonstrated on artificial data, from which it recovers known features and weights, and on two real data sets involving the similarity of a set of geometric shapes and the abstract conceptual similarities of the 10 Arabic numerals. On the basis of these results, the relationship between the multidimensional scaling approach adopted by the network and an alternative additive clustering approach to feature extraction is discussed.     

Prognostic factors and etiology in patients with severe community-acquired pneumonia admitted at the ICU. Spanish multicenter study. Study Group on Severe Community-Acquired Pneumonia in Spain

OBJECTIVE: To determine the techniques used for the etiological diagnosis of community-acquired pneumonia in patients admitted to the intensive care unit (ICU) and to describe the predominant causative organisms as well as prognostic factors of ICU mortality. PATIENTS AND METHODS: A total of 262 patients with community-acquired pneumonia admitted to 26 ICUs between 1 November of 1991 and 31 October of 1992 were included in a prospective, open, multicenter study. RESULTS: The diagnostic techniques most frequently used were blood culture (243 cases) and simple tracheal aspirate (166 cases). Simple tracheal aspirate (58.4%), bronchoalveolar lavage (47.7%), and protected-specimen brush (44.2%) were the techniques that showed the highest diagnostic reliability. In 220 cases, techniques considered of high diagnostic probability were employed. With the use of these procedures, the most frequent causative pathogens were Streptococcus pneumoniae (13.6%) and Legionella pneumophila (9.5%). In 100 cases (45.5%), no pathogen was isolated. A total of 88 patients (33.6%) died during the ICU stay. Predictive variables of poor outcome selected by means of a multivariate analysis were as follows: multisystemic failure (OR = 28.6; 95% CI: 12.8-65.1; p = 0.0001), APACHE II at the time of ICU admission (OR = 5.3; 95% CI: 2.5-11.3; p = 0.0001), progression and/or spread of lung infection (OR = 4.5; 95% CI: 2.4-8.4; p = 0.0001), and shock on admission (OR = 8.48; 95% CI: 4.5-15.9; p = 0.0001). CONCLUSIONS: In 45.5% of patients with community-acquired pneumonia admitted to ICU, no causative pathogen was identified. The prognosis of these patients was influenced by the severity of disease assessed by APACHE II score and presence of multisystemic failure and shock at the time of ICU admission.     

Modifications of U2 snRNA are required for snRNP assembly and pre-mRNA splicing

Among the spliceosomal snRNAs, U2 has the most extensive modifications, including a 5' trimethyl guanosine (TMG) cap, ten 2'-O-methylated residues and 13 pseudouridines. At short times after injection, cellularly derived (modified) U2 but not synthetic (unmodified) U2 rescues splicing in Xenopus oocytes depleted of endogenous U2 by RNase H targeting. After prolonged reconstitution, synthetic U2 regenerates splicing activity; a correlation between the extent of U2 modification and U2 function in splicing is observed. Moreover, 5-fluorouridine-containing U2 RNA, a potent inhibitor of U2 pseudouridylation, specifically abolishes rescue by synthetic U2, while rescue by cellularly derived U2 is not affected. By creating chimeric U2 molecules in which some sequences are from cellularly derived U2 and others are from in vitro transcribed U2, we demonstrate that the functionally important modifications reside within the 27 nucleotides at the 5' end of U2. We further show that 2'-O-methylation and pseudouridylation activities reside in the nucleus and that the 5' TMG cap is not necessary for internal modification but is crucial for splicing activity. Native gel analysis reveals that unmodified U2 is not incorporated into the spliceosome. Examination of the U2 protein profile and glycerol-gradient analysis argue that U2 modifications directly contribute to conversion of the 12S to the 17S U2 snRNP particle, which is essential for spliceosome assembly.     

Adolescent egocentrism and cognitive functioning during late adolescence

The relationship between adolescent egocentrism and post-formal thinking was examined in 163 college undergraduates. Participants were administered the Imaginary Audience Scale and the Social Paradigm Belief Inventory. Results showed that females had higher levels of adolescent egocentrism than did males. A weak negative correlation between egocentrism and cognitive reasoning was found for females during late adolescence. The findings are consistent with Peterson and Roscoe's (1991) study of egocentrism in older adolescent females.     

Hyaluronic acid treatment (viscosupplementation) for OA of the knee

Viscosupplementation may be useful in the treatment of OA of the knee when other medical forms of therapy are contraindicated, toxic, or have failed. It may have a role in managing the patient with moderate to severe OA of the knee before considering total knee arthroplasty (Table 2). Viscosupplementation or medical treatment does not replace the need for thigh muscle strengthening or for overweight patients to lose weight. Whether or not efficacy will demand or warrant earlier or repeated use of hyaluronic acid-like products remains to be seen.     

Release of 5-fluorouracil from poly(acrylamide-co-monopropyl itaconate) hydrogels

The aim of this work was to test the application of copolymeric poly(acrylamide-co-monopropyl itaconate) (A-MPI) hydrogels on the release of 5-fluorouracil (5-FU). The equilibrium degree of swelling in saline solution was 83 +/- 2%. 5-FU, as the sodium salt, was trapped in gels by placing it in the polymerization feed mixture. The diffusion coefficients for both swelling of the gels and the release of 5-FU were determined, in addition to the activation energies for both processes. To determine the applicability of these copolymers, A-MPI (75:25) gel was subcutaneously implanted in rats and the drug plasma concentration was determined by HPLC.     

Fracture biology, biomechanics, and internal fixation

The success of orthopedic surgery in ruminants is directly related to the surgeon's knowledge and understanding of bone physiology and mechanics. The relationship of the macro and micro structure and function of bone as it relates to fracture physiology and repair is discussed. A basic review of the biomechanical principles of bone, bone fracture, and fracture repair are presented. The clinical and biomechanical principles of internal fixation are described for fracture repair in ruminants.     

Valproate reduces intake of alcoholic beverage among rats

SETTING: University of Malaya Medical Centre, Kuala Lumpur, Malaysia. OBJECTIVE: To assess the awareness of the ozone layer and the acceptance of the new non-chlorofluorocarbon (CFC) propellant hydrofluoroalkane 134a salbutamol pressurised metered dose inhaler (MDI) Airomir among asthmatic patients. DESIGN: A total of 113 consecutive asthmatic patients aged 12 years and above from the out- and in-patient services of the hospital were interviewed using a questionnaire. RESULTS: Sixty-five per cent of the patients were aware of the existence of the ozone layer, 23% that CFCs play a role in ozone depletion, and only 10% that current MDIs contained CFCs. All the patients felt that pressurised MDIs should be made CFC-free after they had considered the role of CFCs in the destruction of the ozone layer. Eighty-one per cent of 94 patients who preferred the Airomir inhaler over a multi-dose dry powder inhaler for administering bronchodilator medications were willing to switch to the new inhaler once it became available on the market. CONCLUSION: Awareness of the damaging effect of CFCs on the ozone layer among asthmatic patients would encourage them to change to an ozone-friendly, CFC-free pressurised MDI.