A multi-scale method for automatic correction of intensity non-uniformity in MR images

In this paper, a novel multi-scale method for coil sensitivity profile correction is presented based on wavelet transform. A magnetic resonance (MR) image can be decomposed into two spaces by the wavelet transform: approximate space and residual space. The approximate templates in approximate space can be thought of as multi-scale sensitivity profiles of the surface coil for coil correction. When we choose a suitable filter for decomposition, one of the sensitivity profiles should be optimal among the multi-scale sensitivity profiles. The optimal sensitivity profile can be chosen automatically by an analysis of the contents of the two spaces. The multi-scale method does not rely on any data other than the image generated by the MR scanner. The experiment showed promising results based on one-dimensional simulation and images of phantom and human images.

[Identification of a confused species of Euphorbia hirta L. E. indica Lam]

The article reported the morphological and histological identification for Euporbia hirta L. and its confused species E. indica Lam.. It provided evidences for identifying Euphorbia hirta L..

[Identification of traditional Chinese medicine Baizhi with near-infrared spectrum]

In this paper, 8 kinds of traditional Chinese medicines Baizhi were identified by near-infrared spectrum, coping with pattern recognition. The results showed that near-infrared spectrum method in identifying traditional Chinese medicines Baizhi was not only simple, rapid, but also using few examples, noninvasion. This method provided referential information for identifying these traditional Chinese medicines.

Qian-Kun-Nin, a Chinese herbal medicine formulation, attenuates mitochondrial oxidant stress in cardiomyocytes

Qian-Kun-Nin is a Chinese herbal medicine formulation used for several indications, including the treatment of cardiovascular diseases. This formulation contains herbs which possess antioxidant properties. In this study, Qian-Kun-Nin's ability to confer protection to cardiomyocytes against reactive oxygen species (ROS) generated during mitochondrial electron transport inhibition was tested. The intracellular fluorescent probe 2',7'-dichlorofluorescin diacetate (DCFH-DA, sensitive to H(2)O(2) and hydroxyl radicals) was used to assess intracellular ROS, and propidium iodide (PI) was used to assess viability in cultured chick embryonic cardiomyocytes. Qian-Kun-Nin significantly attenuated oxidation of DCFH in cells exposed to the mitochondrial site III inhibitor, antimycin A, consistent with a decrease in oxidative stress. These attenuated oxidant levels were associated with improved cell survival. After antimycin A exposure, Qian-Kun-Nin decreased cell death from 51. 6+/-3.3% in untreated cells to 27.3+/-3.8% in treated cells at 2 h. We conclude that Qian-Kun-Nin attenuates oxidant stress and protects cells from lethal oxidant damage during mitochondrial electron transport inhibition, and thus its therapeutic potential in treating cardiovascular diseases may relate to its antioxidant properties.

Photocatalytic degradation of azo dye in TiO2 suspended solution

The photocatalysis of azo dye, Orange G, by P-25 anatase TiO2 was investigated in this research. The experiments were conducted in a batch reactor with TiO2 powder suspension. Four near-UV lamps were used as the light source. The experimental variables included solution pH level, amount of TiO2, illumination light intensity, and reaction time. A pseudo-first order reaction kinetic was proposed to simulate the photocatalytic degradation of Orange G in the batch reactor. More than 80% of 10 mg/L Orange G decomposition in 60-minute reaction time was observed in this study and fast decomposition of Orange G only occurred in the presence of both TiO2 and suitable light energy. Faster degradation of Orange G was achieved under acid conditions. The degradation rates of Orange G at pH = 3.0 were about two times faster than those at pH = 7.0. Faster degradation of azo dye was observed for greater irradiated light intensity and more TiO2 present during the reaction. The reaction rates were proportional to TiO2 concentration and light intensity with the power order of 0.726 and 0.734, respectively.

Association and activation of fructose 1,6-bisphosphase during unfolding and refolding: spectroscopic and enzymatic studies

Fructose 1,6-biphosphase is a well-characterized oligomer enzyme, and many effectors allosterically control its activity. In this report, we compared the activity, allosteric properties, and conformational changes in its denaturant-induced unfolding processes. In addition, a trpytophan residue has been introduced into the interface between the C1 and C2 subunits to investigate conformational changes during unfolding. Results show that the denaturation curves of WT FruP2ase detected by various methods do not agree, and the dissociation occurs first with a monomeric form existing around 0.4 M GdmCl as shown by gel filtration. The dissociation of all mutants is accompanied by changes in fluorescence intensity. The results suggest that the unfolding of FruP2ase is a complicated, multiphase process. The activation of FruP2ase by GdmCl at low concentrations can be interpreted as a consequence of the effect of monovalent cation. In the refolding experiments, it is found that Mg2+ is not only essential for enzyme activity, but also can assist the enzyme in refolding and association by preventing the formation of aggregates.

Comparison of auscultatory and oscillometric blood pressures

OBJECTIVE

To study the differences in blood pressure readings between the auscultatory and oscillometric (Dinamap model 8100; Critikon, Tampa, Fla) methods.

DESIGN

Survey of 2 blood pressure instruments.

SETTING

Public schools.

PARTICIPANTS

Seven thousand two hundred eight schoolchildren aged 5 through 17 years.

MAIN OUTCOME MEASURE

Blood pressure levels.

RESULTS

For all children combined, Dinamap systolic pressure readings were 10 mm Hg higher (95% confidence interval, -4 to 24 mm Hg) than the auscultatory systolic pressure readings. Dinamap diastolic pressure readings were 5 mm Hg higher (95% confidence interval, -14 to 23 mm Hg) than the auscultatory Korotkoff phase V diastolic pressure readings.

CONCLUSION

These findings preclude the interchange of readings by the 2 methods. Caution must be exercised in the diagnosis of hypertension when an automated device is used.

Structure of the FHA1 domain of yeast Rad53 and identification of binding sites for both FHA1 and its target protein Rad9

Forkhead-associated (FHA) domains have been shown to recognize both pThr and pTyr-peptides. The solution structures of the FHA2 domain of Rad53 from Saccharomyces cerevisiae, and its complex with a pTyr peptide, have been reported recently. We now report the solution structure of the other FHA domain of Rad53, FHA1 (residues 14-164), and identification of binding sites of FHA1 and its target protein Rad9. The FHA1 structure consists of 11 beta-strands, which form two large twisted anti-parallel beta-sheets folding into a beta-sandwich. Three short alpha-helices were also identified. The beta-strands are linked by several loops and turns. These structural features of free FHA1 are similar to those of free FHA2, but there are significant differences in the loops. Screening of a peptide library [XXX(pT)XXX] against FHA1 revealed an absolute requirement for Asp at the +3 position and a preference for Ala at the +2 position. These two criteria are met by a pThr motif (192)TEAD(195) in Rad9. Surface plasmon resonance analysis showed that a pThr peptide containing this motif, (188)SLEV(pT)EADATFVQ(200) from Rad9, binds to FHA1 with a K(d) value of 0.36 microM. Other peptides containing pTXXD sequences also bound to FHA1, but less tightly (K(d)=4-70 microM). These results suggest that Thr192 of Rad9 is the likely phosphorylation site recognized by the FHA1 domain of Rad53. The tight-binding peptide was then used to identify residues of FHA1 involved in the interaction with the pThr peptide. The results are compared with the interactions between the FHA2 domain and a pTyr peptide derived from Rad9 reported previously.

Analysis of the measurement precision of arterial lumen and wall areas using high-resolution MRI

High-resolution MRI may be used to monitor the progression of human carotid atherosclerosis by measuring the lumen and wall area changes over time. The purpose of this study was to analyze the precision of quantitative measurements of lumen and wall areas. Two independent MR scans near the carotid bifurcation were conducted on eight patients within 2 weeks. The error of lumen area measurement was 6. 2%, 9.2%, and 9.7% for T(1), proton density, and T(2)-weighted images, respectively, and the error of wall area measurement was 10. 8%, 10.9%, and 12.0%. The precision of area measurement correlates strongly with image quality.

Detection of dissection and remodeling of atherosclerotic lesions in rabbits after balloon angioplasty by magnetic-resonance imaging

OBJECTIVE

To assess the usefulness of magnetic-resonance imaging (MRI) for monitoring acute changes after angioplasty of preexisting lesions in rabbits with basal lesions similar to those observed in humans.

METHODS

A combination of Fogarty balloon injury (1 week after initiation of diet) and a mildly hypercholesterolemic diet (0.2% cholesterol and 5% peanut oil) was used to promote the rapid formation of atherosclerotic lesions in 16 New Zealand white rabbits. After 5 months of the diet, angioplasty was performed on these lesions with a Grüntzig catheter in both iliac arteries and the abdominal aorta. MRI was used to monitor the initial formation of lesions after 3 and 5 months of the diet, and 2 days, 2 weeks, and 1 and 2 months after angioplasty.

RESULTS

The combination of early Fogarty injury and mildly hypercholesterolemic diet induced fibroproliferative lesions similar to type Vb atherosclerotic lesions seen in humans. Angioplasty induced deep dissections at the shoulders of lesions in the majority of animals. These dissections often extended into the media. The cellular, proliferative response after angioplasty was localized and limited to sites of dissection. A significant increase in area of arterial wall was observed after angioplasty at sites of dissection without any loss of lumen. In contrast, proximal and distal to the sites of injury, there was no change in wall area but a transient reduction in lumen area.

CONCLUSIONS

Comparison of MRI results with histology confirmed that changes in the wall and lumen, including small linear dissections in the lesions and arterial remodeling, are detectable by MRI.

Distribution of ganglioside GM1 in L-alpha-dipalmitoylphosphatidylcholine/cholesterol monolayers: a model for lipid rafts

The distribution of low concentrations of ganglioside GM1 in L-alpha-dipalmitoylphosphatidylcholine (DPPC) and DPPC/cholesterol monolayers supported on mica has been studied using atomic force microscopy (AFM). The monolayers studied correspond to a pure gel phase and a mixture of liquid-expanded (LE) and liquid-condensed (LC) phases for DPPC and to a single homogeneous liquid-ordered phase for 2:1 DPPC/cholesterol. The addition of 2.5-5% GM1 to phase-separated DPPC monolayers resulted in small round ganglioside-rich microdomains in the center and at the edges of the LC domains. Higher amounts of GM1 (10%) give numerous filaments in the center of the LC domains and larger patches at the edges. A gel phase DPPC monolayer containing GM1 showed large domains containing a network of GM1-rich filaments. The addition of GM1 to a liquid-ordered 2:1 DPPC/cholesterol monolayer gives small, round domains that vary in size from 50 to 150 nm for a range of surface pressures. Larger amounts of GM1 lead to coalescence of the small, round domains to give longer filaments that cover 30-40% of the monolayer surface for 10 mol % GM1. The results indicate that biologically relevant GM1 concentrations lead to submicron-sized domains in a cholesterol-rich liquid-ordered phase that is analogous to that found in detergent-insoluble membrane fractions, and are thought to be important in membrane microdomains or rafts. This demonstrates that AFM studies of model monolayers and bilayers provide a powerful method for the direct detection of microdomains that are too small for study with most other techniques.

Visualization of fibrous cap thickness and rupture in human atherosclerotic carotid plaque in vivo with high-resolution magnetic resonance imaging

BACKGROUND

The results of studies of advanced lesions of atherosclerosis suggest that the thickness of the fibrous cap that overlies the necrotic core distinguishes the stable lesion from one that is at high risk for rupture and thromboembolic events. We have developed a high-resolution MRI technique that can identify the fine structure of the lesion, including the fibrous cap, in vivo. The aim of the present study was to determine the agreement between in vivo MRI and lesion architecture as seen on histology and gross tissue examination to identify fibrous cap thickness and rupture.

METHODS AND RESULTS

Twenty-two subjects who were scheduled for carotid endarterectomy underwent MRI with a 3-dimensional multiple overlapping thin slab angiography protocol. The appearance of the fibrous cap was categorized as (1) an intact, thick, (2) an intact, thin, or (3) a ruptured fibrous cap on MRI, gross, and histological sections. Thirty-six sites were available for comparison between MRI and histology. There was a high level of agreement between MRI and histological findings: 89% agreement, kappa (95% CI)=0.83 (0.67 to 1. 0), weighted kappa=0.87. Spearman's correlation coefficient was 0.88 (significant to the 0.01 level).

CONCLUSIONS

These findings indicate that high-resolution MRI with a 3-dimensional multiple overlapping thin slab angiography protocol is capable of distinguishing intact, thick fibrous caps from intact thin and disrupted caps in atherosclerotic human carotid arteries in vivo. This noninvasive technique has the potential to permit studies that examine the relationship between fibrous cap changes and clinical outcome and to permit trials that evaluate therapy intended to "stabilize" the fibrous cap.

Energy landscape of streptavidin-biotin complexes measured by atomic force microscopy

The dissociation of ligand and receptor involves multiple transitions between intermediate states formed during the unbinding process. In this paper, we explored the energy landscape of the streptavidin-biotin interaction by using the atomic force microscope (AFM) to measure the unbinding dynamics of individual ligand-receptor complexes. The rupture force of the streptavidin-biotin bond increased more than 2-fold over a range of loading rates between 100 and 5000 pN/s. Moreover, the force measurements showed two regimes of loading in the streptavidin-biotin force spectrum, revealing the presence of two activation barriers in the unbinding process. Parallel experiments carried out with a streptavidin mutant (W120F) were used to investigate the molecular determinants of the activation barriers. From these experiments, we attributed the outer activation barrier in the energy landscape to the molecular interaction of the '3-4' loop of streptavidin that closes behind biotin.

Recurrence and survival analyses of 1,115 cervical cancer patients treated with radical hysterectomy

Many clinicopathological factors of cervical cancer are still controversial in their prognostic significance. The case records of 1,115 patients who received radical hysterectomy at the Veterans General Hospital, Taipei, from 1980 to 1989 were collected to evaluate prognosis-related factors by univariate and multivariate analyses. The pathology was reviewed retrospectively by one pathologist. Ten parameters known to be prognostic in the literature were included for analysis. Univariate analysis showed that patients with all these factors had higher recurrence rates. However, when the effects of parametrial invasion, progressive stage and stromal invasion were weighed against the presence of lymph node metastasis, their influence on recurrence became unimportant. Nevertheless, these factors still influenced prognosis when there was no lymph node metastasis. Multivariate analysis of both recurrence and survival time in the patients with squamous cell carcinoma shared a consensus that pelvic lymph node metastasis and deep stromal invasion were significant risk factors. We conclude that these simplified and consistent results obtained by multivariate analysis provide a basis for subclassification of patients to predict prognosis and change therapy.

[Cloning and analysis of different regions of SRY promoter]

The luciferase systems were used to assay the promoter activity of SRY gene with clones of different parts of the 5' flanking region within 544 bp which has basal promoter activity. The results were that the 179 bp region from nt. -353 to nt. -174 upstream of the first ATG included a silent element; the 49 bp region from nt. -112 to nt. -63 included an enhanced element and the 63 bp region from nt. -174 to nt. -112 included an essential promoter sequency for gene transcription. These results give some important clues to elucidate the expression and regulation mechanisms of SRY gene.

Tumor suppressor INK4: refinement of p16INK4A structure and determination of p15INK4B structure by comparative modeling and NMR data

Within the tumor suppressor protein INK4 (inhibitor of cyclin-dependent kinase 4) family, p15INK4B is the smallest and the only one whose structure has not been determined previously, probably due to the protein's conformational flexibility and instability. In this work, multidimensional NMR studies were performed on this protein. The first tertiary structure was built by comparative modeling with p16INK4A as the template, followed by restrained energy minimization with NMR constraints (NOE and H-bonds). For this purpose, the solution structure of pl6INK4A, whose quality was also limited by similar problems, was refined with additional NMR experiments conducted on an 800 MHz spectrometer and by structure-based iterative NOE assignments. The nonhelical regions showed major improvement with root-mean-square deviation (RMSD) improved from 1.23 to 0.68 A for backbone heavy atoms. The completion of p15INK4B coupled with refinement of p16INK4A made it possible to compare the structures of the four INK4 members in depth, and to compare the structures of p16INK4A in the free form and in the p16INK4A-CDK6 complex. This is an important step toward a comprehensive understanding of the precise functional roles of each INK4 member.

Time-of-flight MR angiography with Gd-DTPA hexamethylene diamine co-polymer blood pool contrast agent: comparison of enhanced MRA and conventional angiography for arterial stenosis induced in rabbits

Vascular stenoses were induced in the external iliac arteries of New Zealand white rabbits by a combination of hypercholesterolemic diet and repeat balloon injury. Two-dimensional (2D) and three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) was performed with a specifically designed phased array coil in a 1.5 T system. Enhancement with gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) hexamethylene diamine co-polymer (Nycomed: NC 22181), a blood pool MR contrast agent, was measured after contrast administration and compared with pre-contrast images at the same levels. Vessel diameter measurements were obtained at multiple levels and compared with comparable levels on conventional angiograms of the same animals. Stable enhancement, averaging 227% above baseline, was observed with the 3D TOF MRA over the 40 minutes of this study. Enhancement was not observed with the 2D TOF technique. Measurement of the smallest vessels in this study with 3D TOF MRA was slightly improved following contrast enhancement, although both pre- and post-contrast diameter measurements tended to underestimate the assumed true vessel diameter. Thus, Gd-DTPA hexamethylene diamine co-polymer (Nycomed: NC 22181), a blood pool MR contrast agent, produces significant, stable enhancement with the 3D TOF technique and may improve MRA measurement of small vessels.

Landau excitation of spiral density waves in an inhomogeneous disk of stars

Drift-resonant Landau excitation of spiral density waves in a stellar disk of flat galaxies is proposed. This excitation of waves is suggested as a mechanism for the formation of structural features such as spiral arms and the slow dynamical relaxation of galaxies in a regime of hydrodynamical Jeans-type stability.

[Simultaneous determination of magnolol and honokiol in serum and urine by high performance liquid chromatography]

A reversed-phase high performance liquid chromatographic method for simultaneous determination of magnolol and honokiol in serum and urine of rat has been established. Two drugs were determined within 15 minutes by the method on the column with spherisorb C18, by using a mobile phase consisted of methanol-water-glacial acetic acid (70:30:1, V/V) at 1 mL/min, monitored at 294 nm and with a sensitivity of 0.005 AUFS. After 0.25, 1 and 8 hour of administration of the drugs, protein in serum and urine of Wistar rat was precipitated by methanol and magnolol and honokiol in acidified body fluid were determined after being extracted by a mixture of ethyl acetate and ether. Good linear relationship between concentration in serum and urine and peak area in the ranges of 0.05-2 mg/L for magnolol and 0.025-1 mg/L for honokiol was obtained. Good precision and reproducibility were found too. The average recoveries of the two drugs were 95.6% (RSD = 3.85%), 93.8% (RSD = 3.95%) in serum and 96.0% (RSD = 3.83%), 94.9% (RSD = 3.54%) for urine respectively. The lower limit of the method was 0.02 mg/L of magnolol and 0.04 mg/L of honokiol respectively. The results showed that this method is suitable for the determination of magnolol and honokiol in body fluids.

Effect of cocaine on mitochondrial electron transport chain evaluated in primary cultures of neonatal rat myocardial cells and in isolated mitochondrial preparations

Cardiotoxicity is commonly associated with cocaine abuse. Previous studies have indicated that cocaine alters myocardial mitochondrial function. This study was undertaken to investigate the effect of cocaine on activity of the mitochondrial electron transport chain in cultures of neonatal rat cardiomyocytes and in isolated myocardial mitochondria. Cocaine concentrations (10(-5) to 10(-3) M) were used, and these concentrations have been reported in human cocaine users and are within a similar range of cocaine concentrations used in studies in vivo. After 24 hr treatment of cocaine, there was a slight increase in lactate dehydrogenase leakage in the cells treated with cocaine (10(-3) M). Reduction of tetrazolium compounds, neotetrazolium chloride (NTC) and triphenyltetrazolium chloride (TTC) was analyzed in intact cells to assess activity of the mitochondrial electron transport chain. Cocaine (10(-3) M) did not significantly change TTC and NTC reduction. In isolated mitochondria, cocaine (10(-3) M) significantly inhibited glutamate/malate-mediated respiration. These data suggest that cocaine at high concentrations may inhibit complex I of the mitochondrial electron transport chain of myocardial cells.

Possible role of caspase-3 inhibition in cadmium-induced blockage of apoptosis

Cadmium (Cd) and chromium (Cr) are human carcinogens. Cr(VI) is taken up into cells and reduced by cellular reductants to the potential DNA damaging species Cr(V), (IV), and (III). Reactive oxygen species and carbon-based radicals may also be produced during Cr reduction. We previously found that Cd blocks Cr-induced apoptosis, which could allow a larger proportion of genetically damaged cells to escape and become transformed. This study helped define the mechanisms of Cd-induced suppression of apoptosis. Chinese hamster ovary (CHO K1-BH4) cells were treated with either Cd (5-20 microM), Cr(VI) (350 microM), or Cd (5-20 microM) plus Cr(VI) (350 microM) for 3 h and then cultured in metal-free media for an additional 48 h at which time DNA was extracted or nuclei were examined to determine apoptosis. Cd markedly reduced Cr-induced DNA fragmentation and reduced the number of Cr-induced apoptotic cell nuclei to control levels. Additional study investigated the biokinetics and cellular metabolism of Cr. Cd did not alter the cellular Cr accumulation and there were no differences in the levels of reduced glutathione, a compound possibly important in Cr reduction and reflective of the cellular reducing environment. The antiapoptotic effect of Cd was not due to diminished cellular reduction of Cr(VI) as assessed by electron-spin resonance determination of the levels of Cr(V). Thus, Cd suppression of Cr-induced apoptosis is not based on altered Cr toxicokinetics or metabolism. In addition to Cr, Cd also inhibited apoptosis induced by hygromycin B and actinomycin D. Cd was a very effective inhibitor of caspase-3 activity, a central mediator of apoptosis, with nontoxic levels of Cd resulting in up to approximately 60% inhibition. These results indicate that Cd may have a generalized inhibitory effect on apoptosis, possibly by inhibiting caspase-3. Inhibition of apoptosis by Cd may allow a greater portion of genetically damaged cells to survive, or give selective growth advantages, and has implications as a potential nongenotoxic mechanism of Cd carcinogenesis.

Mannitolum infusion on cirrhotic patients with tense ascites treated by paracentesis

OBJECTIVE

To investigate whether albumin can be substituted by mannitolum in cirrhotic patients with tense ascites treated by paracentesis.

METHODS

Sixty-eight patients admitted to this therapeutic procedure were randomly assigned to receive intravenous albumin (36 patients) and mannitolum (32 patients) infusion. In repeated large-volume paracentesis (3-6 L/day), intravenous albumin 20 g or intravenous 20% mannitolum 250 ml were added.

RESULTS

In 24 and 48 hours after paracentesis the mean value of electrolytes, liver and renal functions and various indicators of systemic circulation either in Group 1 or in Group 2 cases were found without changes (P > 0.05). As compared with that before paracentesis, the diameter of spleen vein was increased significantly (P < 0.05). The complications occurring after paracentesis were similar in both groups.

CONCLUSIONS

It was suggested that paracentesis with intravenous infusion of mannitolum is an effective and safe method in treating cirrhotic patients with tense ascites.

[Determination of 5-FU in serumand tissues after nebulization in patients with lung cancer.]

BACKGROUND

To observe the distribution of 5-FU in serum and respiratory system after nebulization in patients with lung cancer.

METHODS

Ten patients with lung cancer were given 40 ml of 1. 25 % 5-FU by nebulization twice every day. At the same time , other 10 patients with lung cancer , chosen as control group , were given 0. 75g of 5-FU intravenously once every day. The concentration of 5-FU in serum and respiratory systemwas determined by chromatography.

RESULTS

The highest concentration of serum 5-FU was (4. 59 +/-1. 77)mg/L in nebulization group and (10. 46 +/-1. 46)mg/L in control group respectively ( P < 0. 001) . Compared with the control group , the 5-FU concentration for nebulization group was remarkably higher in main bronchi ( P < 0. 05) . The 5-FU concentration in peripheral lung and hilar lymph nodes and tumor tissue had no significant difference for both groups ( P > 0. 05) .

CONCLUSIONS

The 5-FU concentration was significantly higher in respiratory system and lower in serum by nebulization than by injection. Nebulization can lessen the toxic reaction and offer a safe and effective route for chemotherapy.