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PubMed2003

Quantifying the lumbar flexion-relaxation phenomenon: theory, normative data, and clinical applications.

STUDY DESIGN: A two-part investigation was conducted: 1) a prospective study of asymptomatic subjects quantitatively comparing trunk mobility to surface electromyographic (sEMG) signals from the erector spinae during trunk flexion; and 2) a prospective repeated-measures cohort study of patients with chronic disabled work-related spinal disorder tested for the flexion-relaxation (FR) phenomenon while measured simultaneously for lumbar spine inclinometric range of motion (ROM). OBJECTIVES: To describe a theoretical model for the potential use of FR unloaded in assessing patients with chronic low back pain patients before and after rehabilitation, and to establish a normative database (Part 1) for subsequent use in comparison to patients with chronic low back pain (Part 2). The second part of the study assessed the clinical utility of combined sEMG and ROM measurements for assessing the FR phenomenon as a test to assist potentially in planning rehabilitation programs, guiding patients' individual rehabilitation progress, and identifying early posttreatment outcome failures. SUMMARY OF BACKGROUND DATA: The FR phenomenon has been recognized since 1951, and it can be reproducibly assessed in normal subjects with FR unloaded. It can be found intermittently in patients with chronic low back pain. Recent studies have moved toward deriving formulas to identify FR, but only a few have examined a potential relation between inclinometric lumbar motion measures and the sEMG signal. No previous studies have developed normative data potentially useful for objectively assessing nonoperative treatment progress, effort, or the validity of permanent impairment rating measures. METHODS: In Part 1, 12 asymptomatic subjects were evaluated in an intra- and interrater repeated-measures protocol to examine reliability of sEMG signal readings in FR, as well as ROM measures at FR and maximum voluntary flexion. The mean sEMG signal averaging right-left electrode recordings, as well as the gross, true, and sacral lumbar ROM measurements, were recorded as normative data. In Part 2, 54 patients with chronic disabled work-related spinal disorder referred as candidates for tertiary functional restoration rehabilitation participated in a standardized assessment protocol for sEMG and ROM measurement before rehabilitation. Those who completed the program were retested with the identical methodology after rehabilitation (n = 34) using the empirically derived cutoff scores for sEMG readings at FR and ROM from Part 1 and prior scientific literature. Pain disability self-reported scores were correlated with sEMG and ROM. Sensitivity and specificity of the sEMG for identifying abnormal motion were assessed. RESULTS: In Part 1, the ability of the experienced testers to measure ROM and sEMG reliably at FR was high (r >or= 0.92; P < 0.001). All asymptomatic subjects achieved FR at a tightly clustered range of mean sEMG signals from 1 to 2.3 microV. Most of the variation between motion at FR and maximum voluntary flexion occurred through the hip (sacral) motion component of the gross (or total) motion measured at T12. In Part 2, posttreatment reliability for ROM, sEMG, and the ability to detect the FR point was high (r >or= 0.82; P < 0.001). More than 30% of the 54 patients tested before treatment demonstrated ability to achieve FR, with FR usually associated with higher ROM than in the non-FR patients. After treatment, 94% of those who completed the program achieved FR, including all those who achieved FR before treatment. Flexion-relaxation was associated with major improvement in ROM and pain disability self-report. CONCLUSIONS: Flexion-relaxation measures a point at which true lumbar flexion ROM approaches its maximum in asymptomatic subjects. This also is the point at which lumbar extensor muscle contraction relaxes, allowing the lumbar spine to hang on its posterior ligaments. The gluteal and hamstring muscles then lower the flexed trunk even further by allowing the pelvis to rotate around the hips. This phenomenon was subsequently found in Part 2 to offer a potentially promising method for individualizing rehabilitation treatment, decreasing unnecessary utilization, identifying potential postrehabilitation treatment failures, and assessing permanent impairment rating validity. Moreover, this is the first study to demonstrate systematically that an absence of FR in patients with chronic low back pain can be corrected with treatment.

Abdomen↗
PubMed1995

Coupling of phytochrome B to the control of hypocotyl growth in Arabidopsis.

Etiolated seedlings of the wild-type (WT) and of the phyB-1 mutant of Arabidopsis thaliana (L.) Heynh. were exposed to red-light (R) and far-red light (FR) treatments to characterize the action of phytochrome B on hypocotyl extension growth. A single R or FR pulse had no detectable effects on hypocotyl growth. After 24-h pre-treatment with continuous FR (FRc) a single R, compared to FR pulse inhibited (more than 70%) subsequent hypocotyl growth in the WT but not in the phyB-1 mutant. This effect of FRc was fluence-rate dependent and more efficient than continuous R (Rc) or hourly FR pulses of equal total fluence. Hypocotyl growth inhibition by Rc was larger in WT than phyB-1 seedlings when chlorophyll screening was reduced either by using broad-band Rc (maximum emission 610 nm) or by using narrow-band Rc (658 nm) over short periods (24 h) or with seedlings bleached with Norflurazon. Hourly R or R+FR pulses had similar effects in WT and phyB-1 mutant etiolated seedlings. It is concluded that phytochrome B is not the only photoreceptor of Rc and that the action of phytochrome B is enhanced by a FRc high-irradiance reaction. Complementary experiments with the phyA-201 mutant indicate that this promotion of a phytochrome B-mediated response occurs via co-action with phytochrome A.

Arabidopsis↗
PubMed2002

Two independent, light-sensing two-component systems in a filamentous cyanobacterium.

Two ORFs, cphA and cphB, encoding proteins CphA and CphB with strong similarities to plant phytochromes and to the cyanobacterial phytochrome Cph1 of Synechocystis sp. PCC 6803 have been identified in the filamentous cyanobacterium Calothrix sp. PCC7601. While CphA carries a cysteine within a highly conserved amino-acid sequence motif, to which the chromophore phytochromobilin is covalently bound in plant phytochromes, in CphB this position is changed into a leucine. Both ORFs are followed by rcpA and rcpB genes encoding response regulator proteins similar to those known from the bacterial two-component signal transduction. In Calothrix, all four genes are expressed under white light irradiation conditions, albeit in low amounts. For heterologous expression and convenient purification, the cloned genes were furnished with His-tag encoding sequences at their 3' end and expressed in Escherichia coli. The two recombinant apoproteins CphA and CphB bound the chromophore phycocyanobilin (PCB) in a covalent and a noncovalent manner, respectively, and underwent photochromic absorption changes reminiscent of the P(r) and P(fr) forms (red and far-red absorbing forms, respectively) of the plant phytochromes and Cph1. A red shift in the absorption maxima of the CphB/PCB complex (lambda(max) = 685 and 735 nm for P(r) and P(fr), respectively) is indicative for a noncovalent incorporation of the chromophore (lambda(max) of P(r), P(fr) of CphA: 663, 700 nm). A CphB mutant generated at the chromophore-binding position (Leu246-->Cys) bound the chromophore covalently and showed absorption spectra very similar to its paralog CphA, indicating the noncovalent binding to be the only cause for the unexpected absorption properties of CphB. The kinetics of the light-induced P(fr) formation of the CphA-PCB chromoprotein, though similar to that of its ortholog from Synechocystis, showed differences in the kinetics of the P(fr) formation. The kinetics were not influenced by ATP (probing for autophosphorylation) or by the response regulator. In contrast, the light-induced kinetics of the CphB-PCB complex was markedly different, clearly due to the noncovalently bound chromophore.

Amino Acid Sequence↗
PubMed2006

The USDA Automated Multiple-Pass Method accurately estimates group total energy and nutrient intake.

The imperative to address the national obesity epidemic has stimulated efforts to develop accurate dietary assessment methods suitable for large-scale applications. This study evaluated the performance of the USDA Automated Multiple-Pass Method (AMPM), the computerized dietary recall designed for the National Health and Nutrition Examination Survey dietary survey, and 2 epidemiological methods [the Block food-frequency questionnaire (Block) and National Cancer Institute's Diet History Questionnaire (DHQ)] using doubly labeled water (DLW) total energy expenditure (TEE) and 14-d estimated food record (FR) absolute nutrient intake as criterion measures. Twenty highly motivated, normal-weight-stable, premenopausal women participated in a free-living study that included 2 unannounced AMPM recalls and completion of the Block and DHQ. AMPM and FR total energy intake (TEI) did not differ significantly from DLW TEE [AMPM: 8982 +/- 2625 kJ; FR: 8416 +/- 2217; DLW: 8905 +/- 1881 (mean +/- SD)]. Conversely, the questionnaires underestimated TEI by approximately 28% (Block: 6365 +/- 2193; DHQ: 6215 +/- 1976; P < 0.0001 vs. DLW). Pearson correlation coefficients for DLW TEE with each dietary method TEI showed a stronger linear relation for AMPM (r = 0.53; P = 0.02) and FR (r = 0.41; P = 0.07) than for the Block (r = 0.25; P = 0.29) and DHQ (r = 0.15; P = 0.53). Most mean absolute FR nutrient intakes were closely approximated by the AMPM but were significantly underestimated by the questionnaires. In highly motivated premenopausal women, the AMPM provides valid measures of group total energy and nutrient intake whereas the Block and DHQ yield underestimations.

Adult↗
PubMed1985

Spectral Characterization and Proteolytic Mapping of Native 120-Kilodalton Phytochrome from Cucurbita pepo L.

A spectral, immunochemical, and proteolytic characterization of native 120-kilodalton (kD) phytochrome from Cucurbita pepo L. is presented and compared with that previously reported for native 124-kD phytochrome from Avena sativa. The molecule was partially purified ( approximately 200-fold) in the phytochrome-far red-absorbing form (Pfr) in the presence of the protease inhibitor, phenylmethylsulfonyl fluoride, using a modification of the procedure initially developed to purify 124-kD Avena phytochrome. The spectral properties of the preparations obtained are indistinguishable from those described for 124-kD Avena phytochrome, including a Pfr lambda(max) at 730 nanometers, a spectral change ratio (DeltaA(r)/DeltaA(fr)) of 1.05, and negligible dark reversion of Pfr to the red-absorbing form (Pr) in the presence or absence of sodium dithionite. This lack of dark reversion in vitro contrasts with observations that Cucurbita phytochrome, like phytochrome from most other dicotyledons, exhibits substantial dark reversion in vivo. Ouchterlony double immunodiffusion analysis with polyclonal antibodies indicates that 120-kD Cucurbita phytochrome is immunologically dissimilar to 124-kD Avena phytochrome. However, despite this dissimilarity, immunoblot analyses of proteolytic digests have identified at least three spatially separate epitopes that are common to both phytochromes. Using endogeneous protease(s), a peptide map for Cucurbita phytochrome has been constructed and the role that specific domains play in the overall structure of the photoreceptor has been examined. One domain near the NH(2) terminus is critical to the spectral integrity of the molecule indicating that this domain plays a structural role analogous to that of a domain near the NH(2) terminus of Avena phytochrome. Proteolytic removal of this domain occurs preferentially in Pr and its removal shifts the Pfr lambda(max) to 722 nm, increases the spectral change ratio to 1.3, and substantially enhances the dark reversion rate. The apparent conservation of this domain among evolutionarily divergent plant species and its involvement in a conformational change upon photoconversion makes it potentially relevant to the mechanism(s) of phytochrome action. Preliminary evidence from gel filtration studies suggests that the 55-kD chromophoreless COOH-terminal region of the polypeptide contains a domain responsible for dimerization of phytochrome monomers.

Journal Article↗
PubMed1985

Light quality effects on corn chloroplast development.

Corn was grown under greenhouse and controlled light quality conditions incluing full spectrum, red (R), and far-red (FR) sources. Young leaf samples were analyzed for pigments, pigment-proteins, membrane polypeptides, and ultrastructure. Chloroplast development in full spectrum white light was similar to that found in R but different from that found in FR plus low R. Compared to greenhouse and R, FR plus low R (670-760) repressed the formation of photosystem I reaction center protein (CP1 + CP1a) and enhanced those of photosystem II (CPa) in both bundle sheath and mesophyll cells. Photosystem II polypeptides were present in both cell types, with the 46 and 34 kilodalton proteins predominant in mesophyll cells. Bundle sheath cells contained relatively more of the 51 kilodalton and less of the 46 kilodalton proteins. However, they also contained measurable amounts of ribulose bisphosphate carboxylase which may interfere with estimates of the 51 kilodalton protein.

Journal Article↗
PubMed1978

Circular dichroic analysis of protein conformation: inclusion of the beta-turns.

The mean residue ellipticity, [theta], at any wavelength, lambda, of a protein in aqueous solution is expressed as [theta]lambda = fH[theta]H infinity(1-k/n) + f beta[theta]beta + ft[theta]t + fR[theta]R with two constraints: 1 > or = fj > or = 0 and sigma fj = 1. The subscripts H, beta, t, and R refer to the helix, beta-form, beta-turn, and unordered form. The fractions, fj's, of 15 proteins are based on X-ray crystallography, ft refers to the net beta-turn after cancelling those residues having dihedral angles of opposite sign. The [theta]H infinity of an infinite helix and its chain-length dependence factor, k, were computed from the myoglobin data (Chen et al., 1974, Biochemistry 13, 3350). The average number of residues per helical segment, n, for 15 proteins was about 10, which can be used for proteins of unknown structure. The reference spectra of other three structural elements are computed by a least-squares method. Once the reference spectra are chosen, the same equation above can be used to estimate the fractions of the secondary structure of a protein from its CD data points between 190 and 240 nm at 1-nm intervals. The computed helical content is usually good to excellent (concanavalin A is a notable exception). Inclusion of the beta-turn in the analysis improves the correlation for the estimates of the beta-form, but the computed beta t values are not significantly correlated with the X-ray results. Matrix formulation proves the equivalence of the least-squares method and the integral curve-fitting.

Animals↗
PubMed1996

The effect of Phoneutria nigriventer (armed spider) venom on arterial blood pressure of anaesthetised rats.

The changes induced in the mean arterial blood pressure of anaesthetised rats following the administration of armed spider (Phoneutria nigriventer) venom have been investigated. The intravenous injection of Phoneutria nigriventer venom (0.1 mg/kg) evoked a brief and reversible decrease in the mean arterial blood pressure whereas a higher dose of venom (0.3 mg/kg) caused a biphasic response characterized by a short-lasting hypotension followed by a sustained and prolonged hypertension (40-50 min). These changes were accompanied by tachycardia, salivation, fasciculations, defecation and respiratory disturbances. Pretreatment of the animals with atropine (10 mg/kg), propranolol (100 mg/kg), phenoxybenzamine (100 mg/kg) and indomethacin (4 mg/kg) did not significantly affect the mean arterial blood pressure changes induced by Phoneutria nigriventer venom. Similarly, the bradykinin B2 receptor antagonist Hoe 140 (D-Arg-[Hyp3,Thi5,DTic7,Oic8]-bradykinin) (0.6 mg/kg), the PAF receptor antagonist WEB 2086 (3-(4-(2-chlorophenyl)-9-methyl-6H-thieno-(3,2f) (1,2,4)-triazolo-(4,3-a) (1,4)-diazepine-2-yl)-(4-morpholinyl)-1-propanone) (20 mg/kg), the tachykinin NK1 receptor antagonist SR 140333 ((S)1-(2-[3-(3,4-dichlorophenyl)-1-(3-iso-propoxyphenyl acetyl) piperidin-3-yl] ethyl)-4-phenyl-1-azoniabicyclo[2.2.2] octane, chloride) (0.5 mg/kg), the tachykinin NK2 receptor antagonist SR 48968 ((S)-N-methyl-N[4-(4-acetylamino-4-phenylpiperidino)-2-(3,4-dichlorophen yl) butyl]benzamide) (0.5 mg/kg) and the nitric oxide synthase inhibitor N omega-nitro-L-arginine methyl ester (10 mg/kg) had no significant effect on the mean arterial blood pressure changes induced by Phoneutria nigriventer venom. The increase in the blood pressure induced by Phoneutria nigriventer venom was also not significantly affected by either the angiotensin II receptor antagonist losartan (10 mg/kg) or the endothelin ETA receptor antagonist FR 139317 ((R)2-[(R)-2-[[1-(hexahydro-1H-azepinyl]carbonyl]amino-4-methyl- pentanoyl]amino-3-[3-(1-methyl-1H-indoyl)]propionyl] amino-3-(2-pyridyl) propionic acid) (30 mg/kg). The ATP-dependent K+ channel antagonist glibenclamide (50 mg/kg) reduced by 40% the hypotension induced by Phoneutria nigriventer venom without affecting the hypertensive response. Pretreatment of the animals with L-type Ca2+ channel antagonists such as verapamil (10-100 micrograms/kg/min), diltiazem (40-120 micrograms/kg/min) and nifedipine (0.3-10 mg/kg) markedly attenuated the hypertension induced by Phoneutria nigriventer venom. Verapamil (30 micrograms/kg/min) and diltiazem (120 micrograms/kg/min) also promptly reversed the established hypertension induced by Phoneutria nigriventer venom when infused 8 min after venom injection. Our results indicate that the brief decrease of blood pressure induced by Phoneutria nigriventer venom is partially due to ATP-dependent K+ channel activation. The prolonged hypertension seems to result from direct Ca2+ entry into vascular and/or cardiac muscles.

Acetylcholine↗
PubMed2006

High irradiance responses involving photoreversible multiple photoreceptors as related to photoperiodic induction of cell division in Euglena.

Little is known about the photoreceptors involved in the photoperiodism of unicellular organisms, which we elucidated by deriving their action spectra. The flagellated alga Euglena gracilis exhibits photoperiodism, with a long-day response in cell reproduction. The underlying clock is a circadian rhythm with photoinductive capability, peaking at subjective dusk and occurring at the 26th hour in continuous darkness (DD) when transferred from continuous light (LL); it regulates photoinduction, a high-irradiance response (HIR), of a dark-capability of progressing through cell division. We derived the action spectra by irradiating E. gracilis with monochromatic light for 3h at around the 26th hour; the action maxima occurred at 380, 450-460, 480, 610, 640, 660, 680, and 740nm. Except for the maximum at 450-460nm, which was always a major maximum, the maxima greatly depended on the red (R)/far-red (FR) ratio of the prior LL. The high R/FR ratio resulted in a dominant major peak at 640nm and minor peaks at 480 and 680nm, whereas the low ratio resulted in dominant major peaks at 610 and 740nm and minor peaks at 380 and 660nm; the critical fluence was minimally about 60mmolm(-2). These HIRs resulted from the accumulation of corresponding low-fluence responses (LFRs) because we found that repetition of a 3-min light/dark cycle, with critical fluences of 1mmolm(-2), lasting for 3h resulted in the same photoinduction as the continuous 3-h irradiation. Moreover, these LFRs expressed photoreversibility. Thus, photoperiodic photoinduction involves Euglena-phytochrome (640 and 740nm) and blue photoreceptor (460nm). Although 380, 480, 610, 660, and 680nm may also represent Euglena-phytochrome, a definite conclusion awaits further study.

Animals↗
PubMed1997

Platelets enhance contractility in perfused rat mesenteric arteries: involvement of endothelin-1.

We investigated the effects of platelet supernatant on pressor responses to norepinephrine in isolated perfused rat mesenteric arteries. Perfusion of the arteries with platelet supernatant for 2 h markedly enhanced the pressor responses to norepinephrine (10(-6) and 3 x 10(-6) M). This enhancement was significantly inhibited by phosphoramidon (10(-4) M), an endothelin converting enzyme inhibitor. Both BQ788 [N-cis-2,6-dimethylpiperidinocarbonyl-L-gamma-methylleucyl-D -1-methoxycarbonyltryptophanyl-D-norleucine] (10(-6) M), an endothelin ET(B) receptor antagonist, and bosentan (Ro47-0203, 4-tert-butyl-N-[6-(2-hydroxy-ethoxy)-5-(2-methoxy-phenoxy)-2,2-bipyri midin-4-yl]-benzenesulfonamide) (10(-5) M), a nonselective endothelin receptor antagonist, also prevented the potentiation of responses to norepinephrine evoked by platelet supernatant, but FR 139317 ((R)2-[(R)-2-[(S)-2-[[1-(hexahydro-1H-azepinyl)]carbonyl]amino-4-+ ++methylpentanoyl] amino-3-[3-(1-methyl-1H-indoyl)]propionyl]amino-3-(2-pyridyl) propionic acid) (10-6 M), an endothelin ET(A) receptor antagonist, had little effect. Suppressor doses of endothelin-1 (3 x 10(-10) M) or sarafotoxin S6c (S6c) (3 x 10(-10) M) potentiated significantly the norepinephrine-induced vasoconstriction, in the same preparation. Moreover, supernatant-induced enhancement of pressor responses to norepinephrine was markedly suppressed by TGF-beta1 neutralizing antibody. Transforming growth factor-beta1 (TGF-beta1) (40 pM) also significantly enhanced the pressor responses to norepinephrine (10(-6) M) and this enhancement was significantly inhibited by phosphoramidon. These results suggest that platelet-derived TGF-beta1 stimulates the vascular production of endothelin-1 and thereby enhances vasoconstrictor responses to norepinephrine. Platelet-induced enhancement of vasoconstrictor responses to norepinephrine seems to be mainly mediated by endothelin ET(B) receptor, in rat mesenteric arteries.

Animals↗
PubMed1998

Pericardial mesothelial cells produce endothelin-1 and possess functional endothelin ETB receptors.

We investigated the endothelin production and endothelin receptor activity of pericardial mesothelial cells obtained from spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. The pericardial mesothelial cells were maintained in vitro and the production of endothelin-1 by these cells was evaluated by using a sensitive sandwich-type enzyme immunoassay for endothelin-1 and big endothelin-1. Endothelin receptor subtypes were pharmacologically analyzed by measuring the changes of intracellular Ca2+ concentration ([Ca2+]i) in pericardial mesothelial cells. Mesothelial cells from both strains produced more immunoreactive endothelin-1 than big endothelin-1. The production of immunoreactive endothelin-1 progressively increased in a culture time-dependent manner. The amount of immunoreactive endothelin-1 detected after 72 h in pericardial mesothelial cells of SHR was significantly (P < 0.05) higher than that in the cells of WKY rats (SHR: 196.7 +/- 19.1 pg/10(6) cells; WKY: 122.7 +/- 10.6 pg/10(6) cells). Endothelin-1 and endothelin-3 induced elevation of [Ca2+]i in pericardial mesothelial cells. The selective agonist of the endothelin ETB receptor, sarafotoxin S6c, also induced elevation of [Ca2+]i. The endothelin- and sarafotoxin S6c-induced elevations of [Ca2+]i in pericardial mesothelial cells from SHR were greater than those in mesothelial cells from WKY rats. The endothelin ETB receptor antagonist, IRL 1038 ([Cys11,Cys15]endothelin-1-(11-21)), significantly inhibited the endothelin-1- and endothelin-3-induced changes in [Ca2+]i. The endothelin ETA receptor antagonist, FR 1393171 ((R)2-[(R)-2-[(S)-2-[[1-(hexahydro-1H-azepinyl)]carbonyl]ammino -4-methylpentanoyl]amino-3-[3-(1-methyl-1H-indoyl)]propio nyl]amino-3-(2-pyridyl)propionic acid), did not affect these changes. From these results, pericardial mesothelial cells from both SHR and WKY rats shared the ability to produce endothelin-1 spontaneously in culture, although consistently greater production was detected in cultures of SHR origin. Moreover, pericardial mesothelial cells of SHR origin may have increased numbers of endothelin ETB receptors and/or a more active signal transduction system compared with those of WKY rats. These results suggest that endothelin-1 may play an important role in the pericardium in an autocrine and/or paracrine fashion.

Animals↗
PubMed2003

Bronchial rupture with a left-sided polyvinylchloride double-lumen tube.

Bronchial rupture after intubation with a double-lumen endobronchial tube has been infrequently reported. Overinflation of the bronchial cuff was speculated to be a frequent cause of the bronchial damage. We report the case of a 78-year-old woman with non-small cell carcinoma of the right upper lobe. Her trachea and left main-stem bronchus were intubated with a left-sided polyvinylchloride (PVC) double-lumen endobronchial tube (Broncho-Cath(R) 37 Fr, Mallinckrodth Medical, Athlone, Ireland). She underwent an uneventful right upper lobectomy. At the end of the resection, the surgeons noticed the herniating cuff from the ruptured left main-stem bronchus. Laceration was repaired. Subsequent course of the patient was uneventful: she developed neither bronchial leak nor mediastinitis. Ten days later the patients was discharged home in a satisfactory condition. Factors that seem to increase the risk of injury by a double-lumen tube are discussed.

Aged↗
PubMed2003

Three-dimensional CT evaluation for endovascular abdominal aortic aneurysm repair. Quantitative assessment of the infrarenal aortic neck.

Endovascular grafting of abdominal aortic aneurysms should be offered only to those patients with suitable anatomy. This is especially true at the level of the proximal aortic neck in order to secure long-term proximal fixation. Aortoiliac anatomy is easy to understand conceptually, however, it is difficult to define and measure quantitatively. In this article, we discuss the use of three dimensional computed tomographic angiography to determine aneurysm morphology and select patients for endovascular repair. Specifically, we apply our methods to define and measure angulation of the aorta and iliac arteries. The anatomic definition of the angulation of the proximal aortic neck is emphasized.

Angiography↗
PubMed1979

Maximal work capacity of women during acute hypoxia.

Six healthy women (22--34 yr of age) performed maximal bicycle work in a hypobaric chamber at sea level and at simulated altitudes of 2,130 and 3,050 m (barometric pressures, 758, 586, and 523 Torr). Maximal oxygen uptake (VO2max) decreased 10 and 15% from sea-level values at 2,130 and 3,050 m, respectively. At these altitudes minute ventilation (VEBTPS) increased 17 and 22% respectively, a consequence of increased respiratory rate (fR). Respiratory exchange ratios increased 10 and 14%, and oxygen pulse decreased 9 and 12%, respectively, at 2,130 and 3,050 m. Maximal blood lactates, heart rates, cardiac outputs, and plasma volume shifts were unaffected by these altitudes. Although during maximal work the percentage increases in VEBTPS, fR, and R that resulted from altitude exposure were greater in women than those previously reported for men, the decrements in VO2max were comparable to those in men. The results show that relative to their performance at sea level, men and women have equal ability to perform maximal work at altitudes up to 3,050 m.

Acute Disease↗
PubMed2006

Arachidonate 15-lipoxygenase and ubiquitin as fertility markers in boars.

Accurate semen analysis is an important issue in the swine industry. We evaluated two candidate fertility marker proteins associated with sperm cytoplasmic droplet (CD), including 15-lipoxygenase (15-LOX) and ubiquitin (UBI) in a controlled single-sire artificial insemination (AI) trial. Ejaculates (n=116) were collected from 18 fertile Large White boars monthly for 8 mo, and analyzed by semi-quantitative, densitometry-based Western blotting and flow cytometry with antibodies against 15-LOX and UBI. Data were correlated with farrowing rates (FR) and total numbers of piglets born (TNB) from 1754 AI services by 13 of 18 boars, and compared with a conventional microscopic semen analysis. In semi-quantitative Western blotting, both 15-LOX and UBI were correlated with seasonal changes in the percentage of normal (r=-0.38, P<0.01; r=-0.27, P<0.05, respectively) and CD-bearing spermatozoa (r=0.35, P<0.01; r=0.27, P<0.05, respectively). In flow cytometry, UBI and 15-LOX levels showed seasonal changes coinciding with seasonal changes of FR and TNB, representing 13 boars, 88 ejaculates and 1,232 AI services. There were correlations between flow cytometric values of UBI and FR (r=0.31; P<0.05), adjusted FR (r=0.30; P<0.05), TNB (r=-0.38; P<0.01) and adjusted TNB (r=-0.37; P<0.01). Flow cytometric measurements of 15-LOX correlated negatively with TNB (r=-0.33; P<0.05) and adjusted TNB (r=-0.34; P<0.05). These data suggested that boar fertility estimation could be achieved within a group of fertile boars by the use of objectively measurable fertility markers. Flow cytometry appeared more informative and more practical than semi-quantitative Western blotting. This technology could be further optimized for the selection of the most fertile sires in an artificial insemination program.

Animals↗
PubMed2003

A reevaluation of the role of the heterotrimeric G protein in coupling light responses in Arabidopsis.

Previous studies implicated the involvement of a heterotrimeric G protein in red (R) and far-red (FR) light signal transduction, but these studies utilized pharmacological or gain-of-function approaches and, therefore, are indirect tests. Here, we reexamine the role of the single canonical heterotrimeric G protein in R and FR control of hypocotyl growth using a loss-of-function approach. Single- and double-null mutants for the GPA1, AGB1 genes encoding the alpha and beta subunit of the heterotrimeric G protein, respectively, have wild-type sensitivity to R and FR. Ectopic overexpression of wild type and a constitutive active form of the alpha subunit and of the wild-type beta subunit had no effect that can be unequivocally attributed to altered R and FR responsiveness. These results preclude a direct role for the heterotrimeric G complex in R and FR transduction in Arabidopsis leading to growth control in the hypocotyl.

Arabidopsis↗
PubMed2000

Probing the photoreaction mechanism of phytochrome through analysis of resonance Raman vibrational spectra of recombinant analogues.

Resonance Raman spectra of native and recombinant analogues of oat phytochrome have been obtained and analyzed in conjunction with normal mode calculations. On the basis of frequency shifts observed upon methine bridge deuteration and vinyl and C(15)-methine bridge saturation of the chromophore, intense Raman lines at 805 and 814 cm(-)(1) in P(r) and P(fr), respectively, are assigned as C(15)-hydrogen out-of-plane (HOOP) wags, lines at 665 cm(-)(1) in P(r) and at 672 and 654 cm(-)(1) in P(fr) are assigned as coupled C=C and C-C torsions and in-plane ring twisting modes, and modes at approximately 1300 cm(-)(1) in P(r) are coupled N-H and C-H rocking modes. The empirical assignments and normal mode calculations support proposals that the chromophore structures in P(r) and P(fr) are C(15)-Z,syn and C(15)-E,anti, respectively. The intensities of the C(15)-hydrogen out-of-plane, C=C and C-C torsional, and in-plane ring modes in both P(r) and P(fr) suggest that the initial photochemistry involves simultaneous bond rotations at the C(15)-methine bridge coupled to C(15)-H wagging and D-ring rotation. The strong nonbonded interactions of the C- and D-ring methyl groups in the C(15)-E,anti P(fr) chromophore structure indicated by the intense 814 cm(-1) C(15) HOOP mode suggest that the excited state of P(fr) and its photoproduct states are strongly coupled.

Avena↗
PubMed2006

Bioengineering Functional Copolymers. IX. Poly[(maleic anhydride-co-hexene-1)-g-poly(ethylene oxide)].

Amphiphilic bioengineering copolymers having a combination of hydrophilic/hydrophobic linkages and polyelectrolyte behavior, along with an ability to interact with biomacromolecules, in particular with the invertase enzyme, have been synthesized by (a) complex-radical copolymerization of maleic anhydride (MA, the acceptor) and hexene-1 (H-1, the donor) monomers with benzoyl peroxide as the initiator in 1,4-dioxane at 65 degrees C under high-conversion conditions and (b) subsequent grafting (polyesterification) of synthesized poly(MA-alt-H-1) with alpha-methoxy-omega-hydroxy-poly(ethylene oxide) (PEO). Copolymerizations were also carried out in the steady state, in order to essentially reduce the effect of copolymer composition drift. The values of the monomer reactivity ratios (r(1) and r(2)) determined by using the known terminal models of Fineman-Ross (FR) and Kelen-Tüdös (KT), as well as by nonlinear regression (NLR) analysis, are: r(1) = 0.16 and r(2) = 0.30 (FR), r(1) = 0.14 and r(2) = 0.27 (KT), and r(1) = 0.15 and r(2) = 0.29 (NLR), respectively. All the copolymers and graft copolymers were characterized by FTIR spectroscopy, (1)H{(13)C} NMR spectroscopy, viscometric measurements, and chemical (acid number), thermal (DSC and TGA), and X-ray diffraction analyses. Unlike poly(MA-alt-H-1)s, PEO macrobranched graft copolymers exhibit expressed polyelectrolyte and swelling behavior in diluted and concentrated dioxane solutions, respectively. The copolymer and its PEO hyperbranched derivatives can be used as carriers for enzyme immobilization.

Enzymes, Immobilized↗