Polyacrylamides bearing pendant alpha-sialoside groups strongly inhibit agglutination of erythrocytes by influenza A virus: multivalency and steric stabilization of particulate biological systems.

An alpha-sialoside linked to acrylamide by a short connector (5-acetamido-2-O-(N-acryloyl-8-amino-5-oxaoctyl)-2,6-anhydro-3,5-d ideoxy-D-galacto-alpha-nonulopyranosonoic acid, 1) was prepared. Compound 1 formed high molecular weight copolymers with acrylamide, derivatives of acrylamide, and/or vinylpyrrolidone upon photochemically-initiated free radical polymerization. Those copolymers for which the substituents on the acrylamido nitrogen were small inhibited the agglutination of chicken erythrocytes induced by influenza virus (X-31 (H3N2); a recombinant strain of A/Aichi/2/68 (H3N2) and A/Puerto Rico/8/34 grown in chicken eggs). The inhibitory power of the polymers depended strongly on the conditions of polymerization and the sialic acid content of the polymer. The strongest inhibitors were copolymers (poly(1-co-acrylamide)) formed from mixtures of monomer containing [1]/([1] + [acrylamide]) approximately 0.2-0.7; these copolymers inhibited hemagglutination 10(4)-10(5) times more strongly than did similar concentrations of alpha-methyl sialoside (calculated on the basis of the total concentration of individual sialic acid groups in the solution, whether attached to polymer or present as monomers). Samples polymerized in the presence of low concentrations of cross-linking reagents (bis(acrylamido)methane, BIS, and 2,2'-bis(acrylamido)ethyl disulfide, BAC) also showed increased inhibition (10-10(3)-fold relative to monomers), but their use was limited by their poor solubility. Sterically demanding substituents on any position of the acrylamide component (substituents attached to the vinyl group or N-alkyl groups that are larger than hydroxyethyl) reduced the inhibitory power of the polymer. A 1H NMR assay and a fluorescence depolarization assay showed that poly(1-co-acrylamide) bound to a solubilized trimeric form of the viral receptor for sialic acid (bromelain cleaved hemagglutinin, BHA), less tightly than 1, on a per sialic acid basis. A similar result was also obtained with a model system comprising lactic dehydrogenase (a tetramer) and polymeric derivatives of oxamic acid: that is, poly((28, 29, 30, or 31)-co-acrylamide) had a higher inhibition constant for tetrameric lactic dehydrogenase than did the corresponding monomers (28, 29, 30, or 31) on a per oxamate basis. Poly(1-co-acrylamide) is, in principle, capable of inhibiting the agglutination of erythrocytes by several mechanisms: (1) entropically enhanced binding of the polymer (acting as a polyvalent inhibitor) to the surface of the virus; (2) steric interference of the approach of the virus to the surface of the erythrocyte by a water-swollen layer of the polymer on the surface of the virus; (3) aggregation of the virus induced by the polymer.(ABSTRACT TRUNCATED AT 400 WORDS)

Quantitation of human shoulder anatomy for prosthetic arm control--II. Anatomy matrices.

Part I presented mathematically continuous surfaces and origin-to-insertion centroidal trajectory data for the muscles of the human shoulder. Part II presents linear trajectory data for the same muscles, in addition to kinematic descriptions of the joints. 'Anatomy' matrices for musculature, which convert muscle forces (as estimated by cutaneously monitored EMG signals) to moments, within a prosthetic arm controller, are developed for both the linear and non-linear (centroidal) data, and then compared. Graphical analyses of the muscle functions are also presented via computer-generated 'circle diagrams'.

Quantitation of human shoulder anatomy for prosthetic arm control--I. Surface modelling.

Anatomical data and models for the human shoulder musculo-skeletal system are developed with the intent of quantifying physiological subcomponents of a model-based multi-axis prosthetic limb control scheme which has heretofore been implemented empirically. Part I presents the controller formulation, the surface descriptions of the muscles (and bones), and the centroidal trajectory data of the muscles. The data partially quantify the muscle modelling components of the controller, and set the stage for the analysis of the force-to-moment anatomical conversion factors of Part II.

Osteological individuality indicative of migrant citrus laboring.

Particular features of a skeleton discovered near Dade City, Florida, are consistent with the stresses of a life of migrant citrus laboring. In particular, unusual aspects of the right shoulder skeleton are not manifested bilaterally. Ethnographic data, radiographs from a living citrus worker, and the police investigation also support the hypothesis that these remains were derived from an individual who spent significant time as a citrus fruit picker.

Independent instances of "souvenir" Asian skulls from the Tampa Bay area.

In the summer of 1984, police in Pinellas County, Florida, confiscated six identically colored imported Asian skulls (in a shipping case) from a private citizen. In May 1988, in nearby Hillsborough County, police confiscated a very similar skull from another private citizen, who allegedly had found it in an abandoned house. Aside from slight color differences between the six found in Pinellas County and the one found in Hillsborough County, the skulls are virtually identical in their osteological characteristics and condition and in the vital statistics derived from each. Each skull is as clean and dry as those typically sold by commercial scientific supply outlets in the United States. Each is edentulous (primarily premortem), between approximately 20 and 60 years of age at death, and morphologically Asian. Five of the seven are morphologically male, one is morphologically female, and one is a mosaic with respect to gender-related features. Police, medical examiners, coroners, and forensic anthropologists should be aware of such "souvenir" specimens, in the event that they encounter similar skulls. Discriminant function analyses for race and sex yield considerably conflicting results, which underscores the need for using extreme caution when interpreting forensic science estimates based on such techniques.

Merits of random forests emerge in evaluation of chemometric classifiers by external validation.

Real-world applications will inevitably entail divergence between samples on which chemometric classifiers are trained and the unknowns requiring classification. This has long been recognized, but there is a shortage of empirical studies on which classifiers perform best in 'external validation' (EV), where the unknown samples are subject to sources of variation relative to the population used to train the classifier. Survey of 286 classification studies in analytical chemistry found only 6.6% that stated elements of variance between training and test samples. Instead, most tested classifiers using hold-outs or resampling (usually cross-validation) from the same population used in training. The present study evaluated a wide range of classifiers on NMR and mass spectra of plant and food materials, from four projects with different data properties (e.g., different numbers and prevalence of classes) and classification objectives. Use of cross-validation was found to be optimistic relative to EV on samples of different provenance to the training set (e.g., different genotypes, different growth conditions, different seasons of crop harvest). For classifier evaluations across the diverse tasks, we used ranks-based non-parametric comparisons, and permutation-based significance tests. Although latent variable methods (e.g., PLSDA) were used in 64% of the surveyed papers, they were among the less successful classifiers in EV, and orthogonal signal correction was counterproductive. Instead, the best EV performances were obtained with machine learning schemes that coped with the high dimensionality (914-1898 features). Random forests confirmed their resilience to high dimensionality, as best overall performers on the full data, despite being used in only 4.5% of the surveyed papers. Most other machine learning classifiers were improved by a feature selection filter (ReliefF), but still did not out-perform random forests.

Electromyographic patterns suggest changes in motor unit physiology associated with early osteoarthritis of the knee.

OBJECTIVE: To assess characteristics of active motor units (MUs) during volitional vastus medialis (VM) activation in adults with symptomatic knee osteoarthritis (OA) across the spectrum of radiographic severity and age-comparable healthy control volunteers. METHODS: We evaluated 39 participants (age 65+/-3 years) in whom weight-bearing knee X-rays were assigned a Kellgren & Lawrence (KL) grade (18 with KL grade=0; four each with KL grades=1, 2 and 4; nine with grade 3). Electromyography (EMG) signals were simultaneously acquired using surface [surface EMG (S-EMG)] and intramuscular needle electrodes, and analyzed by decomposition-enhanced spike-triggered averaging to obtain estimates of size [surface-represented MU action potentials (S-MUAP) area], number [MU recruitment index (MURI)] and firing rates [MU firing rates (mFR)] of active MUs at 10%, 20%, 30% and 50% effort relative to maximum voluntary force [maximal voluntary isometric contraction (MVIC)] during isometric knee extension. RESULTS: Knee extensor MVIC was lower in OA participants, especially at higher KL grades (P=0.05). Taking the observed force differences into account, OA was also associated with activation of larger MUs (S-MUAP area/MVICx%effort; P<0.0001). In contrast, the estimated number of active units (MURI/MVICx%effort) changed differently as effort increased from 10% to 50% and was higher with advanced OA (KL=3, 4) than controls (P=0.0002). CONCLUSION: VM activation changes at the level of the MU with symptomatic knee OA, and this change is influenced by radiographic severity. Poor muscle quality may explain the pattern observed with higher KL grades, but alternative factors (e.g., nerve or joint injury, physical inactivity or muscle composition changes) should be examined in early OA.

The role of the restorative dentist in the diagnosis and maintenance phases of implant therapy--Part III: The restoration and maintenance of oral health prior to the provision of the implant prosthesis.

Establishing and maintaining the patient's oral health prior to provision of the definitive implant restoration is the responsibility of the restorative dentist and is an important aspect of comprehensive treatment. The additional time and expense required to provide oral hygiene and conventional dental treatment needs to be acknowledged by the implant team and the patient. An anticipated three to five treatment hours are often required to provide maintenance and hygiene care, with additional time needed to provide individualized conventional dental treatment to each patient. The provision of implant therapy is a rewarding experience when all aspects of treatment are properly planned and competently performed. The general practitioner is the logical resource to provide much of the necessary treatment that is directly and indirectly related to the provision of implant restorative dentistry.

Patient classification in home health care: are we ready?

This longitudinal descriptive study retrospectively profiled the acutely ill patient in home health care and explored the utility of using patient record data in predicting agency resource use and patient outcome. The findings suggest that those variables traditionally relied on for reimbursement qualification and as components of patient-classification schemes may not be wholly adequate to explain resource use and patient outcome in the home health setting. Professional nursing judgment of the patient's prognosis was found to be the most sensitive variable predicting outcome. Selected diagnoses and self-care capacity of the patient were the major predictors of resource use. Suggestions are offered for further studies that may move public health nursing more quickly toward the development of consistent and accurate home health care case mix measures.