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PubMed1998

The Weyl character formula, the half-spin representations, and equal rank subgroups.

Let B be a reductive Lie subalgebra of a semi-simple Lie algebra F of the same rank both over the complex numbers. To each finite dimensional irreducible representation Vlambda of F we assign a multiplet of irreducible representations of B with m elements in each multiplet, where m is the index of the Weyl group of B in the Weyl group of F. We obtain a generalization of the Weyl character formula; our formula gives the character of Vlambda as a quotient whose numerator is an alternating sum of the characters in the multiplet associated to Vlambda and whose denominator is an alternating sum of the characters of the multiplet associated to the trivial representation of F.

Journal Article↗

PubMed2004

Relationship between cognitive function and regional cerebral blood flow in different types of dementia.

PURPOSE: We assessed relationships between cognitive impairment and regional cerebral blood flow (rCBF) in the different types of dementia. SUBJECTS AND METHODS: Subjects, who included 27 with Alzheimer's disease (AD), seven with frontotemporal dementia (FTD), six with vascular dementia (VaD), and 12 normal controls, were evaluated using the Mini-mental State (MMS), Kana-hiroi Test, an auditory verbal learning test (AVLT), a word fluency test (WFT) and Raven's Coloured Progressive Matrices (RCPM). The rCBF was measured using a three-dimensional stereotaxic ROI template method (3DSRT). RESULTS: In all dementia types, left superior frontal hypoperfusion was demonstrated. In AD and VaD significant CBF reduction also was seen in both angular, temporal, occipital, and precentral, both hippocampi, thalami, and pericallosal regions, and the left lenticular nucleus. MMS, Kana-hiroi Test, and AVLT scores correlated with CBF in all regions. WFT scores were correlated highly with CBF in the left side in frontal, temporal, and angular regions and right and left lenticular nuclei, thalami, and pericallosal regions. RCPM scores correlated with CBF in posterior regions. CONCLUSION: Close coupling was evident between reduced rCBF and cognitive dysfunction in patients with dementia. Use of neuropsychologic tests and rCBF determinations in combination should enhance diagnostic accuracy.

Aged↗

PubMed1977

Morbid obesity: problems associated with operative management.

A review of the problems associated with extensive jejunoileal bypass for morbid obesity in a series of 175 carefully selected patients is presented. Five postoperative deaths occurred (3%). Nonfatal complications occurred in 21%, with wound infections (14 patients) being the most common. Good results marked by weight reduction to the range of ideal weight without significant electrolyte or metabolic aberrations was observed in 82% of the patients receiving the current dimensional modificatiom of end-to-end jejunoileal bypass (30 cm to 20cm). An additional 13% had fair results and only 5% had poor results. There were six deaths during follow-up: liver failure in four patients (secondary to alcohol abuse in two), myocardial infarction in one, and one from unknown causes. Bypass reversal was necessary for refractory liver failure in three patients (two from alcohol abuse), and for persistent diarrhea with secondary electrolyte depletion in two patients. One of these patients was complicated by severe emotional instability. This experience suggests that the majority of carefully selected patients will have a good response to jejunoileal bypass.

Adolescent↗

PubMed1979

Analyses of oligosaccharides by tagging the reducing end with a fluorescent compound. I. Application to glycoproteins.

The reducing end sugar of an oligosaccharide and 2-aminopyridine were linked by means of reductive amination with sodium cyanoborohydride. The fluorescent derivative of the oligosaccharide thus obtained, which had a positive charge, was subjected to two-dimensional paper electrophoresis. In the first direction, the sugar derivative moved according to its degree of polymerization, and in the second direction, it moved according to the structure of the borate complex. In this way fluorescent derivatives of saccharides were mapped on a sheet of paper. The method was applied to some known mono- and oligosaccharides and to the saccharides obtained by nitrous deamination of the oligosaccharide portions of glycoproteins (fetuin, Take-amylase A, and ovalbumin). The fingerprints thus obtained were characteristic of the chemical structures of the original oligosaccharides.

Aminopyridines↗

PubMed1989

Insulin and insulinlike growth factor 1 (IGF-1) receptors during central nervous system development: expression of two immunologically distinct IGF-1 receptor beta subunits.

Insulin and insulinlike growth factor 1 (IGF-1) receptors are present in brain, yet their function remains obscure. Expression of these tyrosine kinase-bearing growth factor receptors during rat brain development was examined by using three antipeptide antibodies directed against epitopes in the beta subunits (AbP2, AbP4, and AbP5). All three antibodies recognized both insulin and IGF-1 receptors. Membranes were prepared from fetal brains (14 to 21 days of gestation), neonatal brain (postnatal day 1), and adult brain. Immunoblot analyses using AbP4 and AbP5 revealed a 92-kilodalton (kDa) protein that corresponded to the beta subunit of the insulin and IGF-1 receptors. Densitometric scanning of immunoblots indicated that receptor proteins were 4- to 10-fold more abundant in fetal brain membranes than in membranes from adult brain. Expression was highest during 16 to 18 days of gestation and declined thereafter to the relatively low level found in adult brain. Immunoblot analyses with AbP2 as well as ligand-activated receptor autophosphorylation revealed an additional protein of 97 kDa. This protein was phosphorylated in response to IGF-1 and was not directly recognized by AbP4 or AbP5. The covalent association of the 97-kDa protein with the 92-kDa beta subunit was indicated by the ability of AbP4 and AbP5 to immunoprecipitate both proteins under nonreducing conditions but only the 92-kDa protein after reduction. In contrast, AbP2 immunoprecipitated both proteins regardless of their association. This immunospecificity remained unchanged after deglycosylation of the isolated proteins. Two-dimensional tryptic phosphopeptide analysis showed that the 92- and 97-kDa subunits of the IGF-1 receptor are related but distinct proteins. Taken together, the data suggest that the 92- and 97-kDa subunits differ in primary amino acid sequence. Thus, two distinct beta subunits may be present in a single IGF-1 receptor in brain. These subunits have in common an epitope recognized by an antibody to the tyrosine kinase domain (AbP2) but differ in regions thought to be important in receptor kinase regulation and signal transduction.

Animals↗

PubMed1997

Differential patterns of osteoblast dysfunction in trabecular bone in patients with established osteoporosis.

AIMS: To analyse osteoblast function in 153 cases of established osteoporosis as previous work has indicated that osteoporosis is a heterogeneous condition characterised by different patterns of osteoclast and osteoblast dysfunction. METHODS: Histomorphometric data from 153 cases with established osteoporosis was used to analyse osteoblast function, using the following parameters: osteoblast number was assessed using the ratio of osteoblast surface to bone surface (ObS:BS); the percentage of active osteoblasts was assessed by using mineralising surface as a proportion of osteoid surface (sLS + dLS/OS); and the efficiency of active osteoblasts was assessed using the ratio of double to total labelled surface (dLS:tLS). The values of each parameter were standardised using age and sex matched control data and a three dimensional matrix was used to identify groups of patients with similar patterns of altered function. RESULTS: The largest group (60 cases) showed a reduction in all three parameters, while a small group (9 cases) had normal osteoblast function. However, one group showed reduction in osteoblast number only (23 cases), while another group showed a normal number of osteoblasts but both reduced percentage and efficiency of activity (14 cases). The results also suggest that efficiency of activity falls first and that this eventually leads to exit from the active pool. CONCLUSIONS: These results demonstrate the presence of heterogeneity of osteoblast dysfunction in osteoporosis, indicating that the disease is caused by interference at a variety of target sites along the pathway of osteoblast proliferation, differentiation, and activation. Greater understanding of this pathway and of the variety of alterations in the pathway that can occur in osteoporosis may allow more focused therapy for different patient groups identified on the basis of histomorphometric analysis.

Cell Count↗

PubMed1995

Ventilation distribution and regional lung impedance during partial unilateral bronchial obstruction.

Significant degrees of main-stem bronchial obstruction may not have a detectable effect on ventilation distribution at normal breathing frequencies. We determined the effect of graded left main-stem bronchial obstruction (area reduction of 50 and 70%) on the distribution of tidal volume (VT) and mean lung volume (VL) using radioactive 13NN and two-dimensional planar positron imaging in six supine anesthetized tracheotomized dogs. Measurements were made during eucapnic high-frequency oscillatory ventilation at frequencies (f) of 0.2, 1, 5, and 10 Hz. Right and left lung respiratory system complex impedance (Z) values were assessed by simultaneous measurements of dynamic regional lung volume by positron imaging and carinal pressure. The results show a progressive shift of VT away from the obstruction at f > 1 Hz, with VT left-to-right (L/R) ratios of 0.9, 0.9, 0.58, and 0.46 at f of 0.2, 1, 5, and 10 Hz, respectively, for 70% obstruction. VT shifts with f for 50% obstruction were similar but of lesser magnitude. VL L/R ratio was 0.88 and did not change with f or obstruction. The real part of Z was frequency dependent and increased at low f independent of obstruction. The real part of Z L/R ratio increased with obstruction at 5 and 10 Hz. At low f there was a difference between left and right imaginary parts of Z due to the difference in VL. There was no significant change in the imaginary part of Z as a result of obstruction. We conclude that up to a 70% unilateral bronchial obstruction is not detectable by distribution of ventilation at f < or = 1 Hz.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Obstruction↗

PubMed1988

Disappearing false aneurysm of the ventricular septum without rupture: a complication of acute inferior myocardial infarction--a case report.

An interseptal false aneurysm of the left ventricle due to the dissection of the septum in a patient with acute inferior myocardial infarction is described. The aneurysm was demonstrated as a cystic bulge of the left ventricular cavity into the inferoposterior interventricular septum with a small orifice from the left ventricle without any protrusion or rupture into the right ventricular cavity. Two-dimensional echocardiography, magnetic resonance imaging, and dynamic computed tomography were the most useful and reliable noninvasive diagnostic modalities. Repeated examinations demonstrated a significant reduction of the aneurysm in six months.

Aged↗

PubMed2003

Independent spectral representations of images for recognition.

In recent years, studies have shown that independent components of local windows of natural images resemble the receptive fields of cells in the early stages of the mammalian visual pathway. However, the role of the independence in visual recognition is not well understood. We argue that the independence resolves the curse of dimensionality by reducing the complexity of probability models to the linear order of the dimension. In addition, we show empirically that the complexity reduction does not degrade the recognition performance on all the data sets that we have used with an independent spectral representation. In this representation, an input image is first decomposed into independent channels given by the estimated independent components from training images, and each channel's response is then summarised by using its histogram as an estimate of the underlying probability model along that dimension. We demonstrate the sufficiency of the proposed representation for image characterization by synthesizing textures and objects through sampling and for recognition by applying it to large data sets. Our comparisons show that the independent spectral representation often gives improved recognition performance.

Journal Article↗

PubMed2000

Layered expression scanning: rapid molecular profiling of tumor samples.

Layered expression scanning is a new approach to comprehensive molecular analysis of tumor samples that uses a layered array of capture membranes coupled to antibodies or DNA sequences to perform multiplex protein or mRNA analysis. Cell or tissue samples are transferred through a series of individual capture layers, each linked to a separate antibody or DNA sequence. As the biomolecules traverse the membrane set, each targeted protein or mRNA is specifically captured by the layer containing its antibody or cDNA sequence. The two-dimensional relationship of the cell populations is maintained during the transfer process, thereby producing a molecular profile of each cell type present. Reduction-to-practice of the technique is demonstrated by analysis of prostate-specific antigen (PSA) protein, gelatinase A protein, and POV1 (PB39) cDNA. As layered expression scanning technology progresses, we envision a laboratory method that will have multiple applications for high-throughput molecular profiling of normal and tumor samples.

Amino Acid Transport System y+L↗

PubMed1991

[Acetabular roof reconstruction with femoral head bone-graft for severe acetabular deficiency in total hip replacement].

From July 1984 to September 1989 at Taichung Veterans General Hospital, 14 patients (15 hips) received femoral head bone-grafting by modified Harris method as a part of their total hip replacement for acetabular bony deficiencies. They were followed up for an average of 31.7 months (range from 7 to 66 months). The clinical results were classified as excellent (58.3%) and good (41.7%) by Harris hip scoring system. All the grafts presented as "solid incorporation" with the pelvic wall and only one of the grafts was assessed to be "definite resorption" (volume reduction greater than 50%) by radiologic study. The "biologic viability" of these grafts were proved to be positive by scintigraphy in three-dimensional technique (SPECT). According to our limited experience and primary follow-up studies, we found that good clinical results depend on ideal positioning of the acetabular component in the true acetabulum and femoral head bone-grafting is an ideal procedure for the reconstruction of severe acetabular dysplasia in total hip arthroplasty.

Acetabulum↗

PubMed1989

Effects of galactose depletion from oligosaccharide chains on immunological activities of human IgG.

We previously reported a decrease in the content of galactose residues in oligosaccharide chains of serum IgG from patients with rheumatoid arthritis, which was presumed to affect the 3 dimensional structure of CH2 domain. In the present study, we prepared the galactose depleted IgG (agalacto IgG) and characterized its immunological activities. Significant reduction in Clq binding and Fc receptor binding was observed in agalacto IgG. However, IgM rheumatoid factor binding and protein A binding were the same as with intact IgG. Our results implied the biological function of the carbohydrate moiety of human IgG.

Arthritis, Rheumatoid↗

PubMed1984

Effect of desmethylimipramine and reserpine on the concentration of specific proteins in the parietal cortex and the hippocampus of rats as analyzed by two-dimensional gel electrophoresis.

The effect of desmethylimipramine (DMI) and reserpine on the concentration of specific proteins in the parietal cortex and the hippocampus of rats was assessed using two-dimensional gel electrophoresis combined with computer-assisted scanning densitometry. Chronic administration of DMI for 3 weeks was found to produce a significant reduction in the concentration of two proteins in both brain regions examined. Both of these proteins have a molecular weight of approximately 57,000 daltons and isoelectric point of 6.2 to 6.3. A third, smaller protein (MW 28,000 daltons, isoelectric point 5.9) was increased in concentration in rats treated repeatedly with DMI. Acute drug treatment was, in all three cases, found to be without effect. In contrast, chronic treatment of rats with reserpine produced effects on these three proteins in the hippocampus which were quantitatively opposite to those obtained after chronic DMI administration. Again, acute drug treatment was without effect. These results demonstrate that chronic, but not acute, administration of agents affecting noradrenergic reactivity can also have an effect on the concentration of specific proteins within the central nervous system and are of interest in view of the known effects of these drugs on neurotransmitter and enzyme systems in the central nervous system.

Animals↗

PubMed1995

Structure and epitope specificity of the O-specific polysaccharide of Proteus penneri strain 12 (ATCC 33519) containing the amide of D-galacturonic acid with L-threonine.

O-specific polysaccharide was isolated from Proteus penneri strain 12 (ATCC 33519) lipopolysaccharide (LPS) and studied using NMR spectroscopy, including selective spin-decoupling, one-dimensional NOE, two-dimensional homonuclear correlation spectroscopy, 13C,1H heteronuclear correlation spectroscopy and chemical methods (O-deacetylation, Smith degradation, partial acid hydrolysis followed by borohydride reduction and methylation). The amide of D-galacturonic acid with L-threonine [D-GalA(L-Thr)] was identified as a constituent of the polysaccharide and the following structure of the tetrasaccharide repeating unit was established: [formula: see text] where the degree of O-acetylation at either position varies over 20-40%. Serological study with LPS, its degradation products and related synthetic glycoconjugates (2-acrylamidoethyl glycosides of amides of alpha-D-GalA with L-amino acids copolymerised with acrylamide) showed that D-GalA(L-Thr) plays an important role in manifesting the serological specificity of the P. penneri 12 O-antigen. Serological cross reactions between LPSs of P. penneri 12 and Proteus mirabilis S1959, R14/S1959 (transient-like form), O23 and O28 are discussed.

Amides↗

PubMed2005

Ultrasound attenuation measurement in the presence of scatterer variation for reduction of shadowing and enhancement.

Pulse-echo ultrasound display relies on many assumptions that are known to be incorrect. Departure from these makes interpretation of conventional ultrasound images difficult, and three-dimensional (3-D) visualizations harder still. For instance, shadowing and enhancement are the result of an incorrect assumption that sound attenuation is a function only of depth. Attempts to reduce such artefacts by estimating attenuation locally have been frustrated by large statistical variations and the influence of scatterer type. We address the latter by examining the influence of scatterer type on two existing attenuation estimation algorithms. This analysis is novel for one of the algorithms, and contains a correction to previously published work for the other. We then propose a novel algorithm that is less sensitive to scatterer variation. We also present a novel technique for handling large statistical variations based on combined assumptions of monotonicity and smoothness. We then assess the performance of each algorithm for correcting shadowing and enhancement in in vitro data, using a real time 3-D radio frequency (RF) ultrasound acquisition system developed for this purpose. The results show visible differences in attenuation estimates from each technique, which are supported by the theoretical analysis. The novel attenuation estimation algorithm does show less sensitivity to scatterer variation, though it results in a more noisy estimate. Nevertheless, the novel technique for reducing statistical variations is sufficient to allow some degree of correction of shadowing and enhancement in each case.

Algorithms↗

PubMed1996

Step length reductions in advanced age: the role of ankle and hip kinetics.

BACKGROUND: Aging is associated with a reduction in gait velocity, which is due to a shortened step length. This study investigated the relationship between joint kinetics and step length. METHODS: Three-dimensional gait kinematics and kinetics were measured during usual pace gait in 26 older subjects (average age 79) and in 32 young subjects (average age 26). Gait measures were obtained at maximal velocity in five older subjects. Lower extremity strength was measured in the older subjects on an isokinetic dynamometer. RESULTS: Older persons had a 10% shorter step length during usual gait, when corrected for leg length (.65 +/- .07, .74 +/- .04/leg length, respectively, p < .001). Older persons had reduced ankle plantarflexion during late stance (13 +/- 5 degrees, 17 +/- 5 degrees, p = .02) and lower ankle plantarflexor power (2.9 +/- 0.9 W kg-1, 3.5 +/- 0.9 W kg-1, respectively, p = .007). Ankle strength was associated with plantarflexor power developed during late stance (r = .49, p < .001). When gait kinetics were corrected for step length, the older subjects developed 16% greater hip flexor power during late stance than younger subjects (estimate of effect: .15 W kg-1, p = .002). Older subjects were unable to increase ankle plantarflexor power at maximal pace, but increased hip flexor power 72% (1.1 +/- 0.3 W kg-1 to 1.9 +/- 1.0 W kg-1, p = .02). CONCLUSIONS: Older subjects had lower ankle plantarflexor power during the late stance phase of gait and appeared to compensate for reductions in plantarflexor power by increasing hip flexor power. Appropriate training of ankle plantarflexor muscles may be important in maintaining step length in advanced age.

Adolescent↗

PubMed2006

Surgical simulation of instrumented posterior occipitocervical fusion in a child with congenital skeletal anomaly: case report.

STUDY DESIGN: Case report of a child with a congenital skeletal anomaly who underwent instrumented surgery at the craniovertebral junction (CVJ). OBJECTIVES: To describe the utility of surgical simulation using three-dimensional full-scale models for preoperative planning. SUMMARY OF BACKGROUND DATA: Instrumented fusion of cervical spine with pedicle screws has several advantages compared with conventional sublaminar wiring, such as stronger fixation and reduction of malalignment. However, studies have reported a risk of injury to the vertebral artery (VA) from the insertion of screws. Especially in pediatric patients, the safety of pedicle screw insertion has not been fully established. METHODS: A 7-year-old girl with a congenital skeletal anomaly presented with gait disturbance and clumsiness of her right hand. Radiographs showed dysplasia of the C1 posterior arch, leading to compression of the spinal cord posteriorly. Data from three-dimensional computed tomography (CT) angiography showed that the right VA was dominant and was shifted medially at the C2 pedicle. A surgical procedure was scheduled to resect the C1 posterior arch and perform an instrumented occiput-C2 fusion with a system of rod and screws. To evaluate the adaptation of the system to the small and deformed anatomic structure of her CVJ, we produced a three-dimensional full-scale model from CT data and performed a simulation of the scheduled surgery. RESULTS: Simulation of the surgery on the model showed acceptable adaptation of the system. However, the right C2 pedicle screw penetrated the medial wall of the VA foramen. In response to these results, we altered the surgical procedure and performed occiput-C3 fixation with a system of contoured loop and wiring. Although the patient had to use a halo-vest for 2 months, no complication occurred during surgery, and she experienced relief of her myelopathy after surgery. CONCLUSIONS: The three-dimensional full-scale model was useful for determining the safety of instrumented posterior occipitocervical fusion for a pediatric patient with a skeletal anomaly.

Atlanto-Occipital Joint↗

PubMed2001

Three-dimensional analysis of alveolar structure in usual interstitial pneumonia.

The etiology of usual interstitial pneumonia (UIP), a progressive lung disease, remains unclear. We examined alveolar structure in UIP three-dimensionally. Lung biopsy specimens from five patients with idiopathic pulmonary fibrosis were used. Sections 150-microm thick were stained with elastica solution for elastic fibers, with alpha-smooth muscle actin antibody for myofibroblasts, with anti-Thomsen-Friedenreich antibody for type-II pneumocytes and with anti-CD34 antibody for blood vessels. We examined them three-dimensionally using a laser confocal microscope or light microscope. In the fibrotic lesions, the thick elastic fibers forming the alveolar framework were not particularly dense considering the reduction in alveolar volume. Near the fibrotic lesions, some of the thin elastic fibers in the alveolar wall were slightly sinuous and ended with rounded tips. Type-II pneumocytes had proliferated and were distributed uniformly over the alveolar surface. Smooth muscle actin filaments were detected only around the alveolar orifice. These findings show that in UIP destruction of the elastic fiber framework of the alveoli may lead to irreversible focal alveolar collapse after damage to the alveolar epithelial cells, and proliferation of type-II pneumocytes may be involved with this elastolysis.

Biopsy↗