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PubMed1987

Polypeptide composition of the mammalian tectorial membrane.

The effects of the enzymes collagenase, pepsin, chondroitinase ABC and keratanase on the polypeptide composition of the mammalian tectorial membrane have been analysed using one dimensional SDS-polyacrylamide gel electrophoresis (SDS-PAGE). After reduction at least ten polypeptides can be consistently and clearly recognized in SDS gels with molecular weights relative to globular protein standards of 245, 235, 190, 165, 155, 145, 100, 93, 60-73 and 35-49 kDa. With the exception of the 60-73 and 35-49 kDa bands all these polypeptides are sensitive to digestion with bacterial collagenase. The 235, 165, 155, 145 and 93 kDa bands also resist degradation by cold, acidic pepsin. Amino acid analysis of whole tectorial membranes demonstrates that glycine accounts for nearly 25% of the total amino acid content, that proline, hydroxyproline and hydroxylysine are present and that amine sugars can be detected in fairly high concentrations. Estimates based on hydroxyproline content suggest that collagens account for 25-50% of the total tectorial membrane protein. Immunoblotting techniques demonstrate the presence of polypeptides cross reacting with antisera to Type II collagen, Type IX collagen and Type V collagen. Results from immunohistochemical studies confirm that these polypeptides are present in the tectorial membrane and are not contaminants of the isolation procedure. Collagenase treatment of tectorial membranes reveals the presence of an additional non-collagenous polypeptide with an apparent molecular weight of 173 kDa on 7.5% polyacrylamide gels, and polydisperse high molecular weight material spreading over a broad range at the top of the gels. This high molecular weight material and the 173, 60-73 and 35-49 kDa non-collagenous polypeptides are pepsin sensitive and all bind wheat germ agglutinin (WGA) suggesting that they contain N-acetyl glucosamine. The 173 kDa band also binds soybean agglutinin (SBA) suggesting the presence of N-acetyl galactosamine. In the absence of reducing agent the 173 and 60-73 kDa bands are no longer observed and high molecular weight material forming a broad band at the top of the separating gel is seen. The electrophoretic behaviour of this non-collagenous, glycosylated, disulphide bonded, high molecular weight material is altered by treatment with keratanase but not by chondroitinase ABC. The results of this study indicate the tectorial membrane contains at least three different collagen types and, in addition to these collagenous proteins, several non-collagenous, glycosylated polypeptides that may account for as much as 50% of the total tectorial membrane protein.

Acetylgalactosamine↗
PubMed2006

Conjoined twins in a trichorionic quadruplet pregnancy after intracytoplasmic sperm injection and quarter laser-assisted zona thinning.

OBJECTIVE: To describe the occurrence and management of conjoined twins (CTs) in a trichorionic quadruplet pregnancy after the transfer of three embryos obtained by intracytoplasmic sperm injection (ICSI) that had undergone assisted zona hatching (AZH) using a noncontact laser. DESIGN: Case report. SETTING: Private and public IVF centers. PATIENT(S): A 38-year-old nulliparous woman. INTERVENTION(S): IVF, diagnosis by two-dimensional, three-dimensional, and four-dimensional ultrasound, selective termination at 12 weeks gestation. MAIN OUTCOME MEASURE(S): Clinical follow-up and delivery. RESULT(S): After diagnosis, counselling, and selective termination, the subsequent prenatal course was uneventful, and two healthy boys were delivered by elective cesarean section at 38 weeks gestation. CONCLUSION(S): Monozygotic twinning (MZT) and CTs could complicate multifetal pregnancies obtained by assisted reproduction techniques. The relationship between CTs, IVF, and AZH should be better studied to fully understand the mechanisms that lead to MZT (with the possible role of AZH) and CTs in MZT, in particular. Three-dimensional and four-dimensional ultrasound improve prenatal assessment of the condition. Selective embryo reduction is a safe procedure for the management of these pregnancies.

Adult↗
PubMed2001

Structure of the O-specific polysaccharide of Vibrio cholerae O9 containing 2-acetamido-2-deoxy-D-galacturonic acid.

The O-specific polysaccharide (OPS) was isolated by mild-acid degradation of the lipopolysaccharide of Vibrio cholerae O9 and studied by carboxyl reduction, sugar and methylation analyses, Smith degradation, and two-dimensional NMR spectroscopy, including COSY, TOCSY, NOESY, and H-detected 1H,(13)C HMQC experiments. The following structure of the pentasaccharide-repeating unit of the OPS was established:

Carbohydrate Conformation↗
PubMedDate not supplied

Patterns of covariation of DSM-IV personality disorders in a mixed psychiatric sample.

The covariation patterns of DSM-IV personality disorders (PDs) were studied in 431 consecutively admitted psychiatric patients. The co-occurrence rate was greater than 50% for all DSM-IV PDs. Both bivariate association tests and loglinear models showed distinct significant covariation patterns among PDs which were stable across confounder strata. DSM-IV PD clusters were not replicated, with the exception of cluster A. Principal-component analysis (PCA) showed the presence of 3 latent dimensions, thus explaining the DSM-IV PD covariation patterns. These results seem to stress the inadequacy of the DSM-IV categorical model of PD assessment. The need for a reduction of axis II categories and the inclusion of a dimensional model in the diagnostic assessment of DSM-IV PDs are discussed.

Adult↗
PubMedDate not supplied

A biochemical logic gate using an enzyme and its inhibitor. 1. The inhibitor as switching element.

Molecular-scale logic systems will allow for further miniaturization of information processing assemblies and contribute to a better understanding of brain function. Of much interest are the pertinent biological systems, some of the basic components of which are biomolecular switching elements and enzyme-based logic gates. In this series of accounts, results of investigations are presented on the implementation of an enzyme/inhibitor logic gate operating under the rules of Boolean algebra. In this report (part 1 of the series), consideration is given to the experimental conditions-particularly the irradiation mode-that affect the performance of proflavine as inhibitor of alpha-chymotrypsin. Also, assessments are made on the reversibility of the process involved and the long-term stability of the system. Moreover, using a theoretical conformational analysis of proflavine and its reduction products, detailed features were established regarding their three-dimensional structure, partial charge distribution, and hydrophobicity. Accordingly, an understanding was reached as to the factors affecting the interaction between these compounds and the enzyme. In part 2 of this series, the actual implementation of an AND logic gate will be presented. This gate involves proflavine and a chemically derivatized alpha-chymotrypsin, and its operation relies on the conclusions reached in this report regarding the optimal mode for controlling the inhibitory activity of proflavine.

Animals↗
PubMed2003

Evolution of green coffee protein profiles with maturation and relationship to coffee cup quality.

Coffee flavor is the product of a complex chain of chemical transformations. The green bean has only a faint odor that is not at all reminiscent of coffee aroma. It contains, however, all of the necessary precursors to generate the unmistakable coffee flavor during roasting. The levels and biochemical status of these precursors may vary in relation to genetic traits, environmental factors, maturation level, postharvest treatment, and storage. To improve our understanding of coffee flavor generation, the sensory and biochemical impact of maturation was assessed. Maturation clearly favored the development of high-quality flavor in the coffee brew. A specific subclass of green coffee beans, however, generated high-quality coffee flavor irrespective of maturation. Biochemical aspects were examined using a dynamic system: immature and mature green coffee suspensions were incubated under air or argon. On the analytical side, a specific pool of flavor precursors was monitored: chlorogenic acids, green coffee proteins, and free amino acids. A link between maturation, the redox behavior of green coffee suspensions, and their sensory scores was identified. Compared to ripe beans, unripe beans were found to be more sensitive to oxidation of chlorogenic acids. Aerobic incubation also triggered the fragmentation or digestion of the 11S seed storage protein and the release of free amino acids.

Amino Acids↗
PubMed2005

Catalyst-assisted vapor-liquid-solid growth of single-crystal Ga2O3 nanobelts.

Mass production of quasi-one-dimensional gallium oxide nanobelts is accomplished through graphite-thermal reduction of a mixture of gallium oxide powders and SnO2 nanopowders under controlled experimental conditions. Sn nanoparticles are located at or close to the tips of the nanobelts and served as the catalyst for the nanobelt growth by a vapor-liquid-solid mechanism. The morphology and microstructure of the nanobelts were characterized by scanning electron microscopy and high-resolution transmission electron microscopy. The Ga2O3 nanobelts grow along the [104] direction, the widths ranged from several tens to several hundreds of nanometers, and the lengths ranged from several tens to several hundreds of micrometers. The growth of Ga2O3 nanobelts is initiated by Sn nanoparticles via a catalyst-assisted vapor-liquid-solid process, which makes it possible to control the sizes of Ga2O3 nanobelts.

Journal Article↗
PubMed2002

Evaluation of pulmonary vein stenosis after catheter ablation of atrial fibrillation.

Pulmonary vein (PV) stenosis has emerged recently as an important issue in patients who received radiofrequency (RF) ablation of atrial fibrillation (AF). Serial pathophysiological responses, including thrombosis, metaplasia, proliferation and neovascularization, may lead to PV stenosis after RF energy application around or inside the PV ostia. The clinical manifestations of PV stenosis consist of chest pain, dyspnea, cough, hemoptysis, recurrent lung infection and pulmonary hypertension. Although PV stenosis can be asymptomatic, its severity may be related to the numbers of stenotic PVs, the degree and chronicity of PV stenosis. The incidence of PV stenosis (defined as luminal diameter reduction >50%) detected by spiral computer tomography scan or three dimensional magnetic resonance angiography was from 0 to 7% per PV after isolation of PVs from left atria. Furthermore, some patients may show late progression of PV stenosis during follow-up. The first choice of treatment for symptomatic PV stenosis is PV angioplasty with stenting; however, restenosis were reported occasionally. Several studies have analyzed the predictors of PV stenosis, and the results are controversial. However, the consensus for prevention of PV stenosis should include less energy application and the ablation site more close to the atrial site.

Angioplasty↗
PubMed1998

Lumping of whole-body physiologically based pharmacokinetic models.

Lumping is a common pragmatic approach aimed at the reduction of whole-body physiologically based pharmacokinetic (PBPK) model dimensionality and complexity. Incorrect lumping is equivalent to model misspecification with all the negative consequences to the subsequent model implementation. Proper lumping should guarantee that no useful information about the kinetics of the underlying processes is lost. To enforce this guarantee, formal standard lumping procedures and techniques need to be defined and implemented. This study examines the lumping process from a system theory point of view, which provides a formal basis for the derivation of principles and standard procedures of lumping. The lumping principle in PBPK modeling is defined as follows: Only tissues with identical model specification, and occupying identical positions in the system structure should be lumped together at each lumping iteration. In order to lump together parallel tissues, they should have similar or close time constants. In order to lump together serial tissues, they should equilibrate very rapidly with one another. The lumping procedure should include the following stages: (i) tissue specification conversion (when tissues with different model specifications are to be lumped together); (ii) classification of the tissues into classes with significantly different kinetics, according to the basic principle of lumping above; (iii) calculation of the parameters of the lumped compartments; (iv) simulation of the lumped system; (v) lumping of the experimental data; and (vi) verification of the lumped model. The use of the lumping principles and procedures to be adopted is illustrated with an example of a commonly implemented whole-body physiologically based pharmacokinetic model structure to characterize the pharmacokinetics of a homologous series of barbiturates in the rat.

Algorithms↗
PubMed2003

Multiple quadrature detection in reduced dimensionality experiments.

A new, simple procedure is proposed which enables acquisition of two or more chemical shifts encoded in a common dimension simultaneously in quadrature. For n chemical shifts projected in a single dimension, the expected effect is obtained by interleaved acquisition and appropriate combination of 2(n) data sets per increment of respective evolution time. The particular chemical shifts can be calculated from sums and differences of signal frequencies obtained by different combination of the acquired data sets. In comparison to the established reduced dimensionality (RD) techniques, the proposed method enhances resolution due to reduction of the number of signals and requires less evolution time increments owing to narrower spectral width in the RD-domain. We show examples of the application of the new approach to the 2D HNCA and HN(CO)CA techniques with two, and 2D HACANH with three frequencies simultaneously encoded in the t(1) evolution period, for (13)C,(15)N-labeled ubiquitin.

Amino Acid Sequence↗
PubMed2001

Head and pelvic movements during a dynamic reaching task in sitting: implications for physical therapists.

OBJECTIVES: To describe the distance reached, speed, and movement of the head and pelvis of healthy volunteers; to describe any influence of age on these variables; and to compare healthy volunteers and subjects with hemiplegia while performing a seated reaching task. DESIGN: Age-matched, case-control study. SETTING: Gait laboratory in a general hospital. PARTICIPANTS: A convenience sample of 53 healthy volunteers (30 women; 23 men; mean age, 57yr; range, 30-79yr) and 5 subjects with hemiplegia (2 women, 3 men; mean age, 65yr; range, 60-78yr) were recruited within 6 weeks poststroke. INTERVENTIONS: Participants sat on a bench with feet supported and reached laterally as far as they could without falling. MAIN OUTCOME MEASURES: The speed, distance reached, and angular movements of the head and pelvis were recorded by using the 3-dimensional movement analysis system. RESULTS: A significant age-related reduction in the distance reached (p < .001), velocity of the movement (p =.000), and pelvic tilt used (p < .01) was found among healthy volunteers. Comparison of data from healthy volunteers and subjects with hemiplegia showed a significant reduction in the angular movements of the heads of subjects with hemiplegia. CONCLUSIONS: The findings suggest conservation of movement with increasing age and stroke. This movement reduction could have negative effects on a subject's ability to make postural changes in response to disturbance and activity. Such information may assist therapists to gain insight into the nature of balance deficits and the adaptive behavior that could result.

Adult↗
PubMed1997

Structure-function relationships of omega-conotoxin GVIA. Synthesis, structure, calcium channel binding, and functional assay of alanine-substituted analogues.

The structure-function relationships of the N-type calcium channel blocker, omega-conotoxin GVIA (GVIA), have been elucidated by structural, binding and in vitro and in vivo functional studies of alanine-substituted analogues of the native molecule. Alanine was substituted at all non-bridging positions in the sequence. In most cases the structure of the analogues in aqueous solution was shown to be native-like by 1H NMR spectroscopy. Minor conformational changes observed in some cases were characterized by two-dimensional NMR. Replacement of Lys2 and Tyr13 with Ala caused reductions in potency of more than 2 orders of magnitude in three functional assays (sympathetic nerve stimulation of rat isolated vas deferens, right atrium and mesenteric artery) and a rat brain membrane binding assay. Replacement of several other residues with Ala (particularly Arg17, Tyr22 and Lys24) resulted in significant reductions in potency (<100-fold) in the functional assays, but not the binding assay. The potencies of the analogues were strongly correlated between the different functional assays but not between the functional assays and the binding assay. Thus, the physiologically relevant assays employed in this study have shown that the high affinity of GVIA for the N-type calcium channel is the result of interactions between the channel binding site and the toxin at more sites than the previously identified Lys2 and Tyr13.

Alanine↗
PubMed1996

Linear dimension reduction of sequences of medical images: III. Factor analysis in signal space.

A method is presented for improving the precision of factor analysis by utilizing physiological information. The first step is an optimal linear dimension reduction, whereby the data are projected onto a low-dimensional signal space. Then principal component analysis is performed in the signal space rather than in the entire data space. This improves the precision of the principal components. Unlike ordinary principal component analysis, the present method is not degraded when the time intervals are subdivided, provided that the signal space is correct. Alternatively, but with identical results, the covariance matrix can be calculated from the whole data space. The covariance matrix is then transformed and principal component analysis is performed in either a low-rank matrix or a low-dimensional submatrix instead of in the whole covariance matrix. Factor analysis using the intersection method with a theory space may be improved by employing the present method. In simulations based on a [11C]flumazenil study with 27 frames, the proposed method required only 58 per cent of the radioactivity to produce the same precision as the intersection method and only 27 per cent when compared to ordinary principal component analysis.

Biophysical Phenomena↗
PubMed1998

High-helical-pitch, cone-beam computed tomography.

The object of a helical, cone-beam computed tomography, HCBCT, system is faster scan times for the volume of interest for a patient. The maximum helical-pitch that still produces good quality images limits the reduction in scan time. Although this is a three-dimensional problem, an extension of the completeness condition for a two-dimensional fan-beam reconstruction method serves as a guide to estimate the maximum helical-pitch. In HCBCT, each pixel in an arbitrary image slice is irradiated over a different range of gantry rotation angles. This leads to the idea of a different, or inconsistent, range of backprojection angles for each pixel in order to increase the helical-pitch while satisfying the completeness condition. Using inconsistent backprojection, the normalized helical-pitch ratio increases from 0.90 to 1.40 (for a source radius of 600 mm and field of view of 500 mm), where the normalized helical-pitch ratio is the linear advance of the patient couch per gantry revolution to the full axial height of the area detector (as projected at the isocentre).

Algorithms↗
PubMed2004

Erectile function following external beam radiotherapy for clinically organ-confined or locally advanced prostate cancer.

BACKGROUND: External beam radiotherapy (XRT) has been a standard treatment for clinically localized prostate cancer. However, preservation of erectile function following XRT is controversial. In this study, the influence of XRT on erectile function of patients with clinically organ-confined or locally advanced prostate cancer was retrospectively evaluated. METHODS: The study included 34 of 84 patients with organ-confined or locally advanced prostate cancer who underwent XRT between 1995 and 2002. Erectile function following radiotherapy was assessed by a simple mailed questionnaire that was constructed for the study. To determine the predictive factors for erectile dysfunction following radiotherapy, data were analyzed by multivariate analysis with the Cox proportional hazards model. RESULTS: The modality of XRT was the only factor to independently predict erectile dysfunction following XRT. The maintenance rates of erectile function were 47.6% at 1 year and 19% at 3 years in patients who received the 3-dimensional conformal radiotherapy, which were significantly higher than in those who received conventional radiotherapy (P = 0.026). CONCLUSIONS: XRT significantly reduced the maintenance rate of erectile function during the follow-up period, with the rate being 19% at 3 years in patients who received 3-dimensional conformal radiation. The XRT modality was involved in the reduction of erectile function. These results suggest that erectile dysfunction is a possible adverse event following XRT.

Aged↗
PubMed2005

Synergy among phytochemicals within crucifers: does it translate into chemoprotection?

The association between cruciferous vegetables and cancer prevention has been linked to glucosinolate derivatives. These phytochemicals enhance endogenous detoxification, leading to inactivation of potential carcinogens before initiation occurs. Two derivatives, indole-3-carbinol (I3C) and 1-cyano-2-hydroxy-3-butene (crambene) were shown in rats to induce a synergistic enhancement of detoxification enzyme activity. To follow up on these findings, a short-term carcinogenicity study using aflatoxin B1 (AFB(1)) was performed in which male F344 rats were fed diets supplemented with these 2 compounds alone or in combination. Groups included a negative control group (no AFB(1), crambene, or I3C), a crambene group (diet 0.150% crambene), an I3C group (diet 0.165% I3C), a high-dose group (diet 0.150% crambene, 0.165% I3C) a low-dose group (diet 0.030% crambene, 0.033% I3C), and a positive control group (AFB(1) treatment only). AFB(1) was administered after 2 wk of dietary pretreatment. Liver sections were scored for lesions including karyomegaly, apoptosis, and biliary hyperplasia and evaluated for expression of the preneoplastic marker glutathione S-transferase-pi (GSTP). I3C and crambene groups were protected against AFB(1) toxicity whereas the low-dose group was not. The high-dose group had scores close to those of the negative controls. For log(10) transformed 2- and 3-dimensional GSTP data, the high-dose group demonstrated synergistic reduction in GSTP-positive area and an additive reduction in GSTP-positive volume compared with the crambene and I3C groups. The low-dose group had no effect. In conclusion, high combination dietary doses of I3C and crambene demonstrated enhanced protection from AFB(1). Low combination doses, as might be realistically in the diet, were not effective.

Aflatoxin B1↗
PubMed2002

Effects of a splitter plate in the near wake of a divergent trailing edge.

This paper discusses experimental research aimed at defining a base drag reduction device based on splitter plates. The unsteady three-dimensional nature of the flow is studied by Schlieren photography, particle image velocimetry, and measurement of the total unsteady lift and drag loads.

Image Processing, Computer-Assisted↗
PubMed2000

Effects of intracoronary tissue-type plasminogen activator treatment in kawasaki disease and acute myocardial infarction.

We retrospectively studied 3 patients with Kawasaki disease (KD) and acute myocardial infarction (AMI) who were treated with intracoronary administration of tissue-type plasminogen activator (t-PA). Two-dimensional echocardiogram on the next day of the treatment revealed reduction of thrombus and improvement of the cardiac function in all 3 patients. However, a 12-month-old patient treated with 200,000 U/kg of t-PA at 48 h after the onset of AMI died of recurrent myocardial infarction. The other 2 patients treated with 400,000 and 800,000 U/kg, respectively, showed clear, though not prompt, improvement in clinical symptoms and laboratory data. The intracoronary thrombolytic therapy using high-dose t-PA appears effective in treating AMI associated with KD.

Coronary Angiography↗