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PubMed2000

Quality of life in psychiatry: a systematic contribution to construct validation and the development of the integrative assessment tool "modular system for quality of life".

The aim of the present study is to contribute to an ongoing validation process of the Quality of Life (QoL) construct in the clinical field by investigating its internal structure. Eight (inter)nationally validated questionnaires have been analyzed by an integrative approach in a multicenter study. Data has been collected in a mentally healthy (n = 479), a depressed (n = 171) and a schizophrenic (n = 139) sample. Apart from conventional psychometric criteria a similarity structure analysis (SSA) within a facet analytic methodology has been applied. A dimensional structure of the resulting integrative questionnaire "Modular System for Quality of Life" (MSQoL) could be generated that consists of one "G-factor" (life in general) and six specific dimensions (physical health, vitality, psychosocial relationships, material resources, affect, leisure time). This basic structure represents a core module measured by 47 items which is sufficiently valid for all three samples. The empirical structures of healthy, depressed and schizophrenic samples fulfill the first law of attitude and share a common variance of 95%. In addition, there are four specific modules (demography, family, partnership, profession). No specific modules could be identified for the psychopathological subgroups. The conclusion can be drawn that QoL is construed very similar by all three investigated populations which is the base for searching for quantitative differences and profiles. The MSQoL integrates the non-redundant components of eight QoL-instruments, is psychometrically able to assess the basic structure and can be completed within a cumulative research design by items specific for a particular setting.

Adolescent↗
PubMed1999

Emergence of symmetric, modular, and reciprocal connections in recurrent networks with Hebbian learning.

While learning and development are well characterized in feedforward networks, these features are more difficult to analyze in recurrent networks due to the increased complexity of dual dynamics - the rapid dynamics arising from activation states and the slow dynamics arising from learning or developmental plasticity. We present analytical and numerical results that consider dual dynamics in a recurrent network undergoing Hebbian learning with either constant weight decay or weight normalization. Starting from initially random connections, the recurrent network develops symmetric or near-symmetric connections through Hebbian learning. Reciprocity and modularity arise naturally through correlations in the activation states. Additionally, weight normalization may be better than constant weight decay for the development of multiple attractor states that allow a diverse representation of the inputs. These results suggest a natural mechanism by which synaptic plasticity in recurrent networks such as cortical and brainstem premotor circuits could enhance neural computation and the generation of motor programs.

Animals↗
PubMed1999

Artificial disc replacement with the modular type SB Charité III: 2-year results in 50 prospectively studied patients.

The Modular Type SB Charite disc prosthesis has been developed as a device for artificial disc replacement (ADR) in patients with symptomatic discopathies. Here, we report on our first series of 50 (out of 350) patients, who had a satisfactory clinical result in 70% of cases (2 years' follow-up). Subgroup analysis revealed that patients with an isolated discopathy without previous spinal operations or other pathology at the same or other spinal level benefitted more from the surgery. However, this technique was associated with some problems: a 13% rate of permanent side-effects and/or complications was observed caused by the anterior approach. Four percent were related to poor implantation technique. There were no problems related to the material of the prosthesis. Twelve patients needed re-operation, but this was beneficial in only three of them. In one patient we had to convert to an interbody fusion. We conclude that in patients with severe isolated symptomatic discopathies that are resistant to conservative treatment, a mobile disc prosthesis is worth considering as a real alternative to a spondylodesis. However, accurate patient selection is imperative. With these criteria we were encouraged by our results to continue the implantation of this artificial disc.

Adult↗
PubMed2000

Modular organization and identification of a mononuclear iron-binding site within the NifU protein.

The NifS and NifU nitrogen fixation-specific gene products are required for the full activation of both the Fe-protein and MoFe-protein of nitrogenase from Azotobacter vinelandii. Because the two nitrogenase component proteins both require the assembly of [Fe-S]-containing clusters for their activation, it has been suggested that NifS and NifU could have complementary functions in the mobilization of sulfur and iron necessary for nitrogenase-specific [Fe-S] cluster assembly. The NifS protein has been shown to have cysteine desulfurase activity and can be used to supply sulfide for the in vitro catalytic formation of [Fe-S] clusters. The NifU protein was previously purified and shown to be a homodimer with a [2Fe-2S] cluster in each subunit. In the present work, primary sequence comparisons, amino acid substitution experiments, and optical and resonance Raman spectroscopic characterization of recombinantly produced NifU and NifU fragments are used to show that NifU has a modular structure. One module is contained in approximately the N-terminal third of NifU and is shown to provide a labile rubredoxin-like ferric-binding site. Cysteine residues Cys35, Cys62, and Cys106 are necessary for binding iron in the rubredoxin-like mode and visible extinction coefficients indicate that up to one ferric ion can be bound per NifU monomer. The second module is contained in approximately the C-terminal half of NifU and provides the [2Fe-2S] cluster-binding site. Cysteine residues Cys137, Cys139, Cys172, and Cys175 provide ligands to the [2Fe-2S] cluster. The cysteines involved in ligating the mononuclear Fe in the rubredoxin-like site and those that provide the [2Fe-2S] cluster ligands are all required for the full physiological function of NifU. The only two other cysteines contained within NifU, Cys272 and Cys275, are not necessary for iron binding at either site, nor are they required for the full physiological function of NifU. The results provide the basis for a model where iron bound in labile rubredoxin-like sites within NifU is used for [Fe-S] cluster formation. The [2Fe-2S] clusters contained within NifU are proposed to have a redox function involving the release of Fe from bacterioferritin and/or the release of Fe or an [Fe-S] cluster precursor from the rubredoxin-like binding site.

Amino Acid Sequence↗
PubMed1983

A modular program for analysis of electrophysiological data on a laboratory minicomputer.

In the study of electrophysiological phenomena, the signals to be investigated are often reduced to sampled time series or point processes. Nowadays, the measuring equipment frequently includes one or more micro- and/or minicomputers which perform the data acquisition (including, e.g., A-D conversion and interval measurements) and the subsequent data processing and analysis. This paper describes the structured organization of data measurement and analysis of electrophysiological data performed by a modular software program implemented on a laboratory minicomputer. The program is used in our clinical laboratory by a number of research teams with different experimental objectives. The input data structure for the program has a standardized format, comprising multiplexed data channels preceded by a 256 entry parameter block containing general processing information and specific information concerning the analyses performed. The tasks carried out by the program are the calculation of distributions and correlations, digital filtering and estimation of spectra. The program can easily be extended by writing new software modules.

Computers↗
PubMed1992

The modular architecture of vertebrate collagens.

Collagens are typical mosaic proteins containing a number of shuffled domains. These domains have been classified by sequence similarity in order to characterize their structural and functional relationships to other proteins. This analysis provides an overview of homologies of collagen domains. It also reveals two new relationships: (i) a module common to type V, IX, XI, and XII collagens was found to be homologous to the heparin binding domain of thrombospondin; (ii) the modular architecture of a human type VII collagen fragment was identified. Its N-terminal globular domain contains fibronectin type III repeats located adjacent to a Von Willebrand factor type A module. The proposed structural similarities point to analogous subfunctions of the respective domains in otherwise distinct proteins.

Amino Acid Sequence↗
PubMed1995

Divergent sequence motifs correlated with the substrate specificity of (methyl)malonyl-CoA:acyl carrier protein transacylase domains in modular polyketide synthases.

The amino acid sequences of a large number of polyketide synthase domains that catalyse the transacylation of either methylmalonyl-CoA or malonyl-CoA onto acyl carrier protein (ACP) have been compared. Regions were identified in which the acyltransferase sequences diverged according to whether they were specific for malonyl-CoA or methylmalonyl-CoA. These differences are sufficiently clear to allow unambiguous assignment of newly-sequenced acyltransferase domains in modular polyketide synthases. Comparison with the recently-determined structure of the malonyltransferase from Escherichia coli fatty acid synthase showed that the divergent region thus identified lies near the acyltransferase active site, though not close enough to make direct contact with bound substrate.

Acyl Carrier Protein↗
PubMed1995

In vitro production of monoclonal antibodies in high concentration in a new and easy to handle modular minifermenter.

This paper describes a new and easy to handle reusable minifermenter for high-density culture of hybridoma and other cells. The culture apparatus is composed of two modules: a 40 ml disposable cell culture and antibody production chamber (the 'production module') and a 550 ml medium reservoir (the 'supply module'). The two modules are separated from each other by a dialysis membrane allowing passage of low molecular mass nutrients and metabolites. The monoclonal antibodies are produced and enriched in the production module. The outer part of this module is made from a thin gas-permeable silicone rubber membrane allowing exchange of gases (oxygen and carbon dioxide). To start the culture, the cells are injected into the production module through ports in the silicone rubber which are equipped with Luer Lock connectors. Samples can be removed in the same way. For culturing, the minifermenter is rolled on a roller apparatus in a carbon dioxide-supplied incubator. Depending on the individual properties of the hybridoma cells cultured, cell densities of more than 10 x 10(6) (in some cases up to 35 x 10(6)) cells per ml and monoclonal antibody concentrations of several mg per ml can be obtained in the new minifermenter. On average, 61 mg (range: 9-159 mg) could be produced within 1-4 weeks. In terms of their properties the monoclonal antibodies produced in the new modular minifermenter were indistinguishable from antibodies prepared from ascitic fluid or from the supernatant of conventional stationary culture. The culture method is a useful alternative to the in vivo production method in mice. In addition, it represents a completely new, inexpensive and easy to handle general solution to the problem of culturing cells in high density and obtaining cellular products in high concentrations.

Antibodies, Monoclonal↗
PubMed1992

Modularity of the slit protein. Characterization of a conserved carboxy-terminal sequence in secreted proteins and a motif implicated in extracellular protein interactions.

Since our characterization of the slit cDNA sequence, encoding a protein secreted by glial cells and involved in the formation of axonal pathways in Drosophila, we have discovered that the protein contains two additional sequence motifs that are highly conserved in a variety of proteins. A search of the GenPept database with the 73 amino acids at the carboxy terminus of slit revealed that this region contains significant similarity to a carboxy-terminal domain found in six other exported proteins. This observation has allowed us to define a new carboxy-terminal protein motif. In addition, comparisons with a 202 amino acid domain residing between epidermal growth factor (EGF) repeats in slit shows this region to be conserved in laminin, agrin and perlecan and, strikingly, also to lie between EGF repeats in both agrin and perlecan. Our analysis suggests this motif is involved in mediating interactions among extracellular proteins. Consistent with our previous characterization of the slit protein, both new motifs are found only in extracellular proteins. The identification of these two conserved motifs in slit reveals that the entire 1469 amino acids of the protein are made up of modular regions similar to those conserved in other extracellular proteins.

Amino Acid Sequence↗
PubMed1992

Description of a modular, low cost, eater meter for the study of feeding behavior and food preferences in fish.

The eater meter described in this paper is especially designed for fish studies. It consists of three parts: the detector, the feeder, and the interface between the detector and the feeder. The detector is a rod that closed a circuit (by contact or through a magnetic detector) when stuck by a fish, the feeder is electric and can be of any commercial model, and the interface is a simple electronic device, or a computer. Some preliminary results obtained with rainbow trout, Oncorhynchus mykiss, are also presented in order to illustrate the uses of this modular eater meter for fish.

Animals↗
PubMed1993

A modularized infrared light matrix system with high resolution for measuring animal behaviors.

The current study provides a new modularized infrared light matrix system (about $200 cost) which is designed to measure the horizontal gross or fine movements, vertical motion, clockwise or anticlockwise turnings, freezing time, and total distance traveled in rats. The system records the sequences of animal's activity in a computer-aided system with a resolution of 0.2 s in time or 1.6 cm in space, and permanently stores all the resulting data in file. The behavioral apparatus was tested for its sensitivity and usability by amphetamine-injected rats. It was found that intraperitoneal administration of amphetamine (1.25-2.50 mg/kg), but not normal saline, produced a dose-related increase in either the horizontal gross or fine movements, vertical motion, clockwise or anticlockwise turnings, or total distance traveled. However, amphetamine injections produced a dose-related decrease in freezing time. Apparently, most of the amphetamine-induced responses obtained by other detecting apparatus can be reproduced easily by the present apparatus. The current detection system possesses the following advantages: a) high resolution, b) high expansion potential, and c) precise and simplified algorithms for behavioral parameter analysis.

Algorithms↗
PubMed1987

Flexible ureteropyeloscopy with modular, "disposable" endoscope.

A flexible modular ureteropyeloscope has been utilized in 36 patients. The flexible tips of this instrument can be replaced and have been available in sizes 6.0F, 8.5F, and 11.0F. The instrument was passed successfully into the ureter in 37 of 38 patients. The most frequent indications were surveillance for fragments after lithotripsy and for diagnosis of radiographic abnormalities in the upper tracts. The high success rate in these patients supports wider application of these techniques and indicates the potential for therapeutic procedures through flexible ureteroscopes.

Disposable Equipment↗
PubMed1990

The segment polarity gene armadillo encodes a functionally modular protein that is the Drosophila homolog of human plakoglobin.

The Drosophila segment polarity gene armadillo is required for pattern formation within embryonic segments and imaginal discs. We have found that armadillo is highly conserved during evolution; it is 63% identical to human plakoglobin, a protein found in adhesive junctions joining epithelial and other cells. We have examined arm protein localization in a number of larval tissues and found that arm protein accumulation within cells shares many features with the accumulation of plakoglobin. We have compared the phenotype and molecular lesions responsible for the different arm mutations. Surprisingly, severely truncated proteins retain some function; the degree of function is strictly correlated with the length of the truncated protein, suggesting that the internally repetitive arm protein is modular in function. We present a possible model for the cellular role of arm.

Alleles↗
PubMed1992

A modular numerical model of the cardiovascular system for studying and training in the field of cardiovascular physiopathology.

A modular numerical model of the cardiovascular system has been developed to reproduce the most important circulatory phenomena in terms of pressure and volume relationships. It is an easy tool to use, designed to be used with a friendly approach on any IBM or compatible personal computer: it offers a wide selection of graphical and numerical outputs and can be rearranged easily for a particular experiment. A set of subroutines related to different circulatory phenomena has been developed; they can be assembled easily together and communicate with each other by two variables. A full description of the existing subroutines is presented in this paper with three different application examples resulting from the rearrangement of the existing software modules: the first concerns the behaviour of the natural ventricle model itself and can be regarded as a ventricle stand-alone characterization test in terms of preload and afterload sensitivities, the second is related to the use of a pneumatic ventricle instead of the model of the natural ventricle, and the third is a full model of the cardiocirculatory system.

Cardiology↗
PubMed1996

Effect of manufacturing tolerances on the micromotion at the Morse taper interface in modular hip implants using the finite element technique.

This study reports on the examination of the effect of manufacturing tolerances on the micromotion at the Morse taper interface in modular hip implants. The finite element technique was used as a tool of analysis. Special emphasis was placed on the consideration of the transient dynamic conditions under which a prosthesis works inside the human body. In order to simulate approximately the repetitive forces acting on a hip implant during the human walking cycle, a time-variant sinusoidal load was applied on the head of the taper. The locking of the Morse taper joint by the surgeon in the operating room at the time of implantation was simulated by specifying an axial displacement to the female taper component as an initial condition.

Biomechanical Phenomena↗
PubMed1993

Characterization of Xenopus laevis complement factor I structure--conservation of modular structure except for an unusual insert not present in human factor I.

Factor I (C3b/C4b inactivator) is a regulatory protein of the classical and alternative complement pathways. In this paper, we report the sequence of Xenopus factor I cDNA and the deduced protein structure. The basic structure of human preprofactor I, NH2-heavy chain-cleavage peptide-light chain-COOH, is conserved in the frog. However, the frog heavy chain contains a highly charged segment of 29 amino acids, encoded by a poly dA-rich mRNA insert, which is not found in human factor I. The modular structure of the frog heavy chain was analyzed, and found to differ vis-à-vis previously published analyses of human factor I. We also evaluate the timing of factor I transcription during frog embryogenesis.

Amino Acid Sequence↗
PubMedDate not supplied

Modular construction of nervous systems: a basic principle of design for invertebrates and vertebrates.

The modular construction of brain tissue is not solely a feature of vertebrate nervous tissue, but is characteristic of many invertebrate nervous systems as well. Modern vertebrate and invertebrate modules vary over several orders of magnitude in volume but vary less in diameter. Although the physiological and anatomical differences between the modules discussed herein are overpowering, their importance to nervous system functions are similar. Modules are the serial and parallel processing units that have allowed large-brained animals to evolve. Many invertebrate modules are discrete, hemispherical lobes, visible on the surface of the brain or nerve cord, whereas most mammalian modules are columnar or ellipsoidal tissue compartments that can only be visualized with specific anatomical methods. Lobes from the largest invertebrates can be more voluminous than any neocortical compartments, but these large lobes are usually not single modules. Large invertebrate lobes contain internal compartments that are single modules and of similar size to their vertebrate analogs. However, vertebrate cortical modules or columns, are far more numerous than the compartments in invertebrate brains and in several cases are known to be adjoined laterally into slabs of tissue that extend for several millimeters. Physiological data support the idea that neural modules are not just anatomical entities, but are active local circuits. The specific activities within each type of module will depend upon its neuronal components, both intrinsic and extrinsic, its functional roles and phylogenetic history. Many cellular and intercellular phenomena common to vertebrates and invertebrates underlie the development of modules. Neuronal and glial interactions and their interplay with the extracellular environment depend upon families of molecules with broad phyletic occurrences. The commonalities of growth mechanisms may to a large degree account for the widespread incidence of neuronal processing units. The strategy of enlarging a nervous system through the replication of the basic units is thought to be advantageous for several reasons. This plan allows nervous systems to economize on the branch sizes and lengths needed for interconnections, to ensure that appropriate targets are reached during development and to modulate specific circuits within a larger network.

Animals↗
PubMed1988

A simple modular tissue bath developed for 'in vitro' studies of the isolated spinal cord.

A tissue bath for studies of the mammalian spinal cord in vitro is described. The modular construction of the bath permits considerable flexibility for accommodating different tissue preparations. The individual components of the bath are easily constructed and the design permits multiple compartment baths to be simply formed. The design principle on which the bath is based may have much wider application than that described.

Animals↗