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Results for “modularity”

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PubMed1995

Total knee replacement including a modular distal femoral component in elderly patients with acute fracture or nonunion.

Distal femoral fracture or nonunion in elderly patients with osteopenic bone and coexisting gonarthrosis poses a difficult treatment challenge. Open reduction and internal fixation with or without the use of bone cement may not provide sufficient stabilization, requires a prolonged period of weightbearing restrictions, and does not address preexisting knee arthrosis. We report five patients, three with distal femoral nonunion, two with acute distal femoral fracture, and all with concomitant gonarthrosis treated with total knee replacement including a modular distal femoral component [distal femoral replacement (DFR)]. In this group of patients, modular DFR provided immediate pain relief and allowed early weightbearing and aggressive rehabilitation. We recommend this treatment modality in selected osteopenic elderly patients with difficult distal femoral reconstructive problems and coexisting gonarthrosis.

Aged↗

PubMed1995

Modular unipolar versus bipolar prosthesis: a prospective evaluation of functional outcome after femoral neck fracture.

Between January 1, 1987, and December 31, 1992, 140 community-dwelling geriatric patients > or = 65 years of age with a displaced femoral neck fracture (Garden III-IV) underwent primary prosthetic replacement and were followed prospectively for a minimum of 1 year. Overall, 92 patients received a cemented bipolar prosthesis and 48 patients received a cemented modular unipolar prosthesis. There were no statistically significant differences between the two groups with respect to preinjury characteristics (age, sex, and number and severity of medical comorbidities) and functional ability. There were no statistically significant differences between the two groups with regard to the number of postoperative complications, length of stay, and 1 year mortality rate. An in-depth functional evaluation was obtained as follows: level of ambulation, independence in basic activities of daily living (feeding, bathing, dressing, toileting), and independence in instrumental activities of daily living (food shopping, food preparation, banking, laundry, housework, and use of public transportation). At 1 year follow-up, no statistically significant differences in functional ability were identified between the unipolar and bipolar groups. Furthermore, at a minimum of 1 year follow-up, there were no statistically significant differences between the two groups with regard to the need for revision surgery or the incidence hip pain. Based on the results of this study, there does not appear to be any advantage to the use of bipolar endoprosthesis for the treatment of femoral neck fractures in the elderly patient. The lower cost of modular unipolar prostheses compared with bipolar prostheses provides additional support for their use.

Aged↗

PubMed1990

Construction of modular circuits in the mammalian brain.

Comparison of seemingly different modular units in the mammalian brain raises the possibility of a common mechanism for their formation: the growth of neuropil mediated by trophic interactions. The ongoing postnatal construction of modular circuits according to trophic interplay may in turn account for the remarkable plasticity of the juvenile brain. By the same token, the normal waning of circuit construction during postnatal development may explain the end of critical periods, the diminished ability to recover from injury in older animals, and the decline with increasing age in the ability of mammals to learn complex skills.

Animals↗

PubMed1996

Modular nature of abscisic acid (ABA) response complexes: composite promoter units that are necessary and sufficient for ABA induction of gene expression in barley.

The modular nature of the abscisic acid response complex (ABRC), the promoter unit necessary and sufficient for abscisic acid (ABA) induction of gene expression in barley, is defined in this study. We investigated ABA induction of a barley late embrogenesis abundant (Lea) gene, HVA1, and found that the ABRC of this gene consists of a 10-bp box with an ACGT core (ACGT-box) and the 11 bp directly upstream, named coupling element 3 (CE3). Only one copy of this ABRC is sufficient to confer ABA induction when linked to a minimal promoter. Because we previously reported another ABRC in the barley HVA22 gene, which consists of an ACGT-box with a distal coupling element (CE1), exchange experiments were conducted to study the interaction among modular elements in these ABRCs. We show that ACGT-boxes in these ABRCs are interchangeable, indicating that an ACGT-box can interact with either a distal or a proximal coupling element to confer ABA response. However, the two coupling elements are not fully exchangeable. Although CE3 can function either proximal or distal to the ACGT-box, CE1 is only functional at the distal position. The presence of both the distal and the proximal coupling elements has a synergistic effect on the absolute level of expression as well as on ABA induction. These ABRCs function in both seed and vegetative tissues. In seeds, ABA induction of the ABRC containing the proximal CE3, but not the ABRC with the distal CE1, is enhanced in the presence of the transcription regulator Viviparous1, indicating that these two ABRCs are mediated by different ABA signal transduction pathways.

Abscisic Acid↗

PubMed1975

The Denver universal microspectroradiometer (DUM). II. Computer configuration and modular programming for radiometry.

This paper describes and discusses for microscopists and spectroscopists the choice of computer equipment and the design of programs used in the Denver Universal Microspectroradiometer (DUM). This instrument is an accurate computerized photon-counting microspectrophotometer, microspectrofluorimeter and microrefractometer. The computer is used to control the operation of the system, to acquire radiometric data of various kinds, and to reduce, analyse and output the data in a readily usable form. Since the radiometer was designed to carry out many kinds of measurements in a variety of micro- and macroscopic specimens, and since different methods of microscopy or spectroscopy have to be combined in various ways fro the study of any one specimen, no single master-program could fulfill efficiently all foreseeable requirements. Therefore, the programming developed is interactive, modular, hierarchical and hybrid. Modular interactive programming makes it possible for almost any kind of main program, applicable to almost any kind of measurement, to be assembled quickly from a collection of hierarchical subroutines. Main programs are short and composed mainly of Fortran statements calling subroutines; subroutines, in turn, automatically call other subroutines over many levels. The subroutines are independently written and optimized for maximum operational efficiency in the computer system used, or for maximum ease of transfer to other systems. This approach to programming enables someone unfamiliar with computer languages to operate the radiometric system from the console of the CRT terminal. The writing of new main programs, by linking groups of existing subroutines, requires only a minimum acquaintance with Fortran; only the writing and revision of subroutines requires programming experience. Differences and similarities in the method of computer operation between the present system and other computerized radiometers are briefly discussed.

Computers↗

PubMed1996

A secreted protein tyrosine phosphatase with modular effector domains in the bacterial pathogen Salmonella typhimurium.

A number of bacterial pathogens have evolved sophisticated strategies to subvert host-cell signal-transduction pathways for their own benefit. These bacteria produce and export proteins capable of specific interactions with key mammalian cell regulatory molecules in order to derail the normal functions of the cells. In this study, we describe the identification of a modular effector protein secreted by the bacterial pathogen Salmonella typhimurium that is required for its full display of virulence. Sequence analysis revealed that a carboxy-terminal region of this protein, which we have termed SptP, is homologous to the catalytic domains of protein tyrosine phosphatases. Purified SptP protein efficiently dephosphorylated peptide substrates phosphorylated on tyrosine. An engineered mutant of SptP in which a critical Cys residue in the catalytic domain was changed to Ser was devoid of phosphatase activity, indicating a catalytic mechanism similar to that of other tyrosine phosphatases. In addition, an amino-terminal region of SptP exhibited sequence similarity to the ribosyltransferase exoenzyme S from Pseudomonas aeruginosa and the cytotoxin YopE from Yersinia spp. The modular nature of this effector protein may allow multiple interactions with host-cell signalling functions.

Amino Acid Sequence↗

PubMed1993

Management of chondrosarcoma including modular ceramic and alumina prosthetic replacement.

Forty-one cases of chondrosarcoma from varying sites throughout the body, and treated exclusively by one of the authors (R.L.H.) from 1972 to 1990 were reviewed. The symptoms, signs, location of tumours, treatment and progress are presented. Particular attention was paid to modular bone replacement techniques. Excision and reconstruction of the bone or joint were carried out in 17 femora, five tibia and six humeri. Comparison between this method of management and other techniques is discussed. Titanium and alumina prostheses for the hip, femur, tibia, shoulder and humerus have been designed by the senior author. These are both inert and modular, and have been found to be superior to other methods of treatment in both function and cosmesis. They do not possess the same potential donor infection risks and other disadvantages of allograft replacement. Immediate postoperative weight bearing and mobilization are possible with these systems. The Huckstep prostheses allow for bony ingrowth into their porous coated alumina sleeves, spacers and stems. In addition, the titanium alloy locking component for the femoral stems has an elasticity half that of other metal alloys and this was found to minimize stress shielding.

Adult↗

PubMed1994

The functional evaluation of patients with primary malignant tumours about the knee treated by modular endoprosthetic replacement.

Between 1985 and 1992, 39 patients with primary malignant neoplasms about the knee presented to the musculoskeletal oncology service at the Royal Prince Alfred Hospital, Sydney. Twenty-eight patients met the criteria for limb salvage surgery and underwent reconstruction using a modular endoprosthetic replacement. Twenty surviving patients and the modular prosthesis were evaluated using the rating system adopted by the Musculoskeletal Tumour Society. Eighteen patients had resection of the distal femur and two had resection of the proximal tibia. The average follow up was 36.5 months (range 6-93). Overall the results were excellent in two patients, good in 16 and fair in two. The prosthesis was rated as excellent in 13, good in four, fair in two and poor in one. The complications encountered are discussed. The authors conclude that this prosthesis provides a satisfactory form of reconstruction following limb salvage surgery for tumours about the knee.

Adolescent↗

PubMed1980

A theory of modular evolution for bacteriophages.

The modular theory of virus evolution has clear experimental support among the temperate bacteriophages of the enteric bacteria. However, there is also similar genetic and DNA heteroduplex evidence for such evolution among other families of bacteriophages: the virulent bacteriophages of the enterics comprise several families: the T-even group, the T3-T7 group (which has many members among different species of bacteria, including bacteria as widely divergent as E. coli and Caulobacter crescentus. It nicely explains the diffusion of very similar homologous bacteriophages into hosts whose own DNAs have diverged very greatly from each other in nucleotide sequence. It also accounts for the rigorous maintenance of regulatory schemes while units of function (including regions coding for proteins) diverge more rapidly. It should also be noted that the considerations that make modular evolution seem advantageous for bacteriophages apply equally well to viruses of higher organisms. Furthermore, the kinds of heteroduplex similarity observed among animal viruses are reminiscent of what is found for bacteriophages. Viruses found in widely divergent hosts show much greater similarity than would be expected; quite possibly animal viruses also evolve as a population of interchangeable modules.

Bacteriophage lambda↗

PubMed1998

Plasposons: modular self-cloning minitransposon derivatives for rapid genetic analysis of gram-negative bacterial genomes.

A series of modular mini-transposon derivatives which permit the rapid cloning and mapping of the DNA flanking the minitransposon's site of insertion has been developed. The basic plasposon, named TnMod, consists of the Tn5 inverted repeats, a conditional origin of replication, rare restriction endonuclease multiple cloning sites, and exchangeable antibiotic resistance cassettes. The broad host range and low target DNA sequence specificity of the Tn5 transposase, in combination with the flexibility afforded by the modular arrangement of TnMod, result in a versatile tool for the mapping of insertional mutations and the rapid recovery of clones from gram-negative bacteria.

DNA Transposable Elements↗

PubMed1993

Efficient transcriptional activation of many simple modular promoters by simian virus 40 large T antigen.

Simian virus 40 (SV40) large T antigen is a multifunctional protein which plays central roles during both lytic and transforming infections by SV40. It is a potent transcriptional activator and increases expression from the SV40 late promoter and from several cellular promoters. To understand better the transcriptional activation activity of large T antigen, we examined its ability to transactivate a set of simple modular promoters containing one of four upstream activation sequences coupled with one of three different TATA box sequences originally constructed and studied by Taylor and Kingston (Mol. Cell. Biol. 10:165-175, 1990). Large T antigen activated transcription from all of these simple promoters. The identity of the TATA box was a more important determinant of the final level of gene expression than was the identity of the upstream activating sequence element. We also determined the ability of a set of mutant SV40 large T antigens to activate a subset of these promoters. Several mutant SV40 large T antigens which had reduced ability to activate the complex SV40 late and Rous sarcoma virus long terminal repeat promoters showed reduced transcriptional activation activity on all of the modular promoters tested. We used a set of promoter derivatives of the human U6 small nuclear RNA promoter containing different TATA boxes and found that wild-type large T antigen could activate transcription from all of them, although to widely different levels of expression.

Animals↗

PubMed1982

Construction of a modular dihydrofolate reductase cDNA gene: analysis of signals utilized for efficient expression.

Dihydrofolate reductase (DHFR) modular genes have been constructed with segments containing the adenovirus major late promoter, a 3' splice site from a variable region immunoglobulin gene, a DHFR cDNA, and portions of the simian virus 40 (SV40) genome. DNA-mediated transfer of these genes transformed Chinese hamster ovary DHFR- cells to the DHFR+ phenotype. Transformants contained one to several copies of the transfected DNA integrated into the host genome. Clones subjected to growth in increasing concentrations of methotrexate eventually gave rise to lines containing several hundred copies of the transforming DNA. Analysis of the DHFR mRNA produced in amplified lines indicated the following. (i) All clones utilize the adenovirus major late promoter for transcription initiation. (ii) A hybrid intron formed by the 5' splice site of the adenovirus major late leader and a 3' splice site from a variable-region immunoglobulin gene is properly excised. (iii) The mRNA is not efficiently polyadenylated at sequences in the 3' end of the DHFR cDNA but rather uses polyadenylation signals downstream from the DHFR cDNA. Three independent clones produce a DHFR mRNA containing SV40 or pBR322 and SV40 sequences, and the RNA is polyadenylated at the SV40 late polyadenylation site. Another clone has recombined into cellular DNA and apparently uses a cellular sequence for polyadenylation. Introduction of a segment containing the SV40 early polyadenylation signal into the 3' end of the DHFR cDNA gene generated a recombinant capable of transforming cells to the DHFR+ phenotype with at least a 10-fold increase in efficiency, demonstrating the necessity for an efficient polyadenylation signal. Attachment of a DNA segment containing the transcription enhancer (72-base pair repeat) of SV40 further increased the biological activity of the modular DHFR gene 50- to 100-fold.

Adenoviridae↗

PubMed1985

TU elements: a heterogeneous family of modularly structured eucaryotic transposons.

We describe here a family of foldback transposons found in the genome of the higher eucaryote, the sea urchin Strongylocentrotus purpuratus. Two major classes of TU elements have been identified by analysis of genomic DNA and TU element clones. One class consists of largely similar elements with long terminal inverted repeats (IVRs) containing outer and inner domains and sharing a common middle segment that can undergo deletions. Some of these elements contain insertions. The second class is highly heterogeneous, with many different middle segments nonhomologous to those of the first-class and variable-sized inverted repeats that contain only an outer domain. The middle and insertion segments of both classes carry sequences that also are found unassociated from the inverted repeats at many other genomic locations. We conclude that the TU elements are modular structures composed of inverted repeats plus other sequence domains that are themselves members of different families of dispersed repetitive sequences. Such modular elements may have a role in the dispersion and rearrangement of genomic DNA segments.

Animals↗

PubMed1988

A modular arrangement of neuronal processes in human cortex: disruption with aging and in Alzheimer's disease.

Studies were undertaken to assess whether or not neuron-specific immunostaining of the human brain can reveal unique cytoarchitectural features that may be affected by healthy aging and Alzheimer's disease (AD). Human prefrontal cortex (PFC) and anterior cingulate cortex (ACC) were stained with an antibody raised against the neurofilament protein 200,000 molecular weight subunit (NFP-200) using an avidin-biotin immunolocalization procedure. Immunostaining of cortex was neuron-specific and highlighted axons in particular. This staining has revealed an orderly arrangement of horizontal and vertical axon bundles which form latticelike compartments or modules throughout most of the matrix of the two cortical areas studied. The ACC shows this pattern to be intact in individuals through the ninth decade, while the PFC there was blurring of the modularity beyond the fifth decade. Irrespective of the age-related blurring of the latticelike arrangement of axons in PFC, neurologically normal elderly individuals nevertheless showed a highly organized appearance to the cortical matrix. By contrast, patients with AD showed a marked disruption of the modular arrangement of fibers in PFC, but not ACC. Differences between PFC fibers in controls and AD patients were also demonstrated with an axon-specific monoclonal antibody that reacted with phosphorylated epitopes of the NFP-200. The chaotic appearance of fiber staining in PFC seen in patients with AD was noted to be present in one subject who died in an early stage of the disease. The possible significance of this previously unknown aspect of cortical cytoarchitecture for normal cognitive functioning in humans is discussed.

Adolescent↗

PubMed1995

Design of a non-constrained, non-cemented, modular, metacarpophalangeal prosthesis.

A non-constrained, non-cemented, modular prosthesis for replacement of the metacarpophalangeal joints of the fingers has been developed. The prosthesis is of a surface design which is modular in construction and is implanted into the bones with a press fit. The prosthesis is designed to be implanted into patients with traumatic injuries, post-traumatic osteoarthritis and into patients with rheumatoid arthritis at an early stage in the disease where the muscles and ligaments that surround the joint are still functional and can provide joint stability.

Arthritis, Rheumatoid↗

PubMedDate not supplied

The Modular Propad and the Softform mattress.

Constant low-pressure supports such as soft mattresses can feel comfortable because they conform well to the shape of the body. When such mattresses are provided with a highly convoluted surface made up of contiguous foam pillars, their efficacy is improved. The Modular Propad is a highly convoluted, but shallow, foam mattress. It is used as an overlay for an ordinary mattress and seems to be superior to earlier forms of convoluted foam overlay. The Softform is a new mattress which has replaceable sections. The outermost sections of the Softform are convoluted foam sheets similar to the Modular Propad. This article discusses the advantages and disadvantages of these products and some potential problems with their covers. It also suggests that the use of a pressure sore risk assessment tool can facilitate the allocation of patients to these special supports.

Beds↗

PubMed1991

Corrosion of modular hip prostheses.

Nine uncemented hip prostheses of modular design were revised because of late infection (2 cases), femoral stem loosening or fracture (2), loosening of threaded cups (3) and protrusion of bipolar cups (2). At surgery we found tissue discoloration and macroscopic corrosion in four of the nine prostheses, located at the head-neck junction. Histological examination in most cases showed extensive necrosis associated with metal particles, indicating metal toxicity. Metallographic examination of the prosthetic heads revealed structural imperfections and inhomogeneity of the metal. We suggest that the crevice between the head and neck is a potential site of corrosion in modular designs.

Adolescent↗

PubMed2025

Modularization of the type II secretion gene cluster from Xanthomonas euvesicatoria facilitates the identification of a structurally conserved XpsCLM assembly platform complex.

Many bacterial pathogens depend on a type II secretion (T2S) system to secrete virulence factors from the periplasm into the extracellular milieu. T2S systems consist of an outer membrane secretin channel, a periplasmic pseudopilus and an inner membrane-associated assembly platform including a cytoplasmic ATPase. The components of T2S systems are often conserved in different bacterial species, however, the architecture of the assembly platform is largely unknown. Here, we analysed predicted assembly platform components of the Xps-T2S system from the plant-pathogenic bacterium Xanthomonas euvesicatoria. To facilitate these studies, we generated a modular xps-T2S gene cluster by Golden Gate assembly of single promoter and gene fragments. The modular design allowed the efficient deletion and replacement of T2S genes and the insertion of reporter fusions. Mutant approaches as well as interaction and crosslinking studies showed that the predicted assembly platform components XpsC, XpsL and XpsM form a trimeric complex which is essential for T2S and associates with the cytoplasmic ATPase XpsE and the secretin XpsD. Structural modeling revealed a similar trimeric architecture of XpsCLM homologs from Pseudomonas, Vibrio and Klebsiella species, despite overall low amino acid sequence similarities. In X. euvesicatoria, crosslinking and fluorescence microscopy studies showed that the formation of the XpsCLM complex is independent of the secretin and vice versa, suggesting that the assembly of the T2S system is a dynamic process which involves the association of preformed subcomplexes.

Xanthomonas↗