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An aqueous system based on a TiO2 layer photosensitized by natural pigment(s) from pomegranate, shows relatively high stability under illumination with a quantum yield of 0.74 and a photovoltage of 0.46 V.
The synthetic conditions for the isolation of the iron-molybdenum nanocluster FeMoC [HxPMo12O40 [subset]H4Mo72Fe30(O2CMe)15O254(H2O)98], along with its application as a catalyst precursor for VLS growth of SWNTs have been studied. As-prepared FeMoC is contaminated with the Keplerate cage [H4Mo72Fe30(O2CMe)15O254(H2O)98] without the Keggin [HxPMo12O40]n- template, however, isolation of pure FeMoC may be accomplished by Soxhlet extraction with EtOH. The resulting EtOH solvate is consistent with the replacement of the water ligands coordinated to Fe being substituted by EtOH. FeMoC-EtOH has been characterized by IR, UV-vis spectroscopy, MS, XPS and 31P NMR. The solid-state 31P NMR spectrum for FeMoC-EtOH (delta-5.3 ppm) suggests little effect of the paramagnetic Fe3+ centers in the Keplerate cage on the Keggin ion's phosphorous. The high chemical shift anisotropy, and calculated T1 (35 ms) and T2 (8 ms) values are consistent with a weak magnetic interaction between the Keggin ion's phosphorus symmetrically located within the Keplerate cage. Increasing the FeCl2 concentration and decreasing the pH of the reaction mixture optimizes the yield of FeMoC. The solubility and stability of FeMoC in H2O and MeOH-H2O is investigated. The TGA of FeMoC-EtOH under air, Ar and H2 (in combination with XPS) shows that upon thermolysis the resulting Fe : Mo ratio is highly dependent on the reaction atmosphere: thermolysis in air results in significant loss of volatile molybdenum components. Pure FeMoC-EtOH is found to be essentially inactive as a pre-catalyst for the VLS growth of single-walled carbon nanotubes (SWNTs) irrespective of the substrate or reaction conditions. However, reaction of FeMoC with pyrazine (pyz) results in the formation of aggregates that are found to be active catalysts for the growth of SWNTs. Activation of FeMoC may also be accomplished by the addition of excess iron. The observation of prior work's reported growth of SWNTs from FeMoC is discussed with respect to these results.
Conditions have been developed for the solubilization of hepatic microsomal carnitine acyltransferase activity in good yield, with excellent long-term stability and with retention of malonyl-CoA sensitivity. Solubilized microsomal carnitine acyltransferase activity can be separated into malonyl-CoA-sensitive and -insensitive activities either by gel filtration on Superdex 200 or by anion-exchange chromatography on Resource Q. On gel filtration the apparent molecular masses of the malonyl-CoA-sensitive and -insensitive activities are approx. 300 kDa and 60 kDa respectively. The malonyl-CoA-sensitive and -insensitive activities have different fatty-acyl-chain-length specificities and different stabilities in the detergent octyl glucoside. Together these findings indicate that the malonyl-CoA-sensitive and -insensitive activities are due to different enzymes. The malonyl-CoA sensitivity of the inhibitable enzyme is markedly increased on reconstitution into soybean L-alpha-lecithin liposomes, demonstrating that phospholipids play a crucial role in the inhibition by this metabolite. Evidence is also provided that the malonyl-CoA-sensitive microsomal carnitine acyltransferase is a different enzyme from the malonyl-CoA-sensitive carnitine palmitoyltransferase found in the mitochondrial outer membrane. The possible physiological role of the two microsomal acyltransferases is discussed.
Fundamental knowledge of pain in the oral mucosa is lacking. We determined the validity and reliability of the pressure-pain threshold (PPT) measurement in the oral mucosa using a newly developed hand-held pressure algometer. Ten dentulous subjects were recruited, and the PPT was measured at the bilateral buccal (on the attached gingiva apical to the midline of the upper first premolars, 3 mm from the mucogingival junction) and the palatal sites (mid-point between the bilateral upper first molars). The PPT linearly increased with an increase in load-rate (P < 0.0001). The PPT yielded a high intra-individual stability both for the same-day consecutive trials and weekly sessions. The palatal site revealed a 4- to 4.65-fold greater PPT than the buccal sites (Bonferroni, P < 0.0001), whereas no difference was found between the bilateral buccal sites (P=0.663). Despite a great interindividual variation in the PPT, significant intra-individual correlations were found among the measurement sites. This suggested differences in individual sensitivity to pain in the oral mucosa, which may determine overall pain sensation specific to an individual. A pressure algometer described herein reliably assessed the PPT in the oral mucosa and sensitively discriminated PPT differences at different sites and at different load-rates, suggesting the reliability and validity of PPT measurements in the oral mucosa for clinical and research investigations.
In this study, we investigated how thyroid hormone (3,5',5-triiodo-l-thyronine, T3) inhibits binding of thyroid hormone receptor (TR) homodimers, but not TR-retinoid X receptor heterodimers, to thyroid hormone response elements. Specifically we asked why a small subset of TRbeta mutations that arise in resistance to thyroid hormone syndrome inhibit both T3 binding and formation of TRbeta homodimers on thyroid hormone response elements. We reasoned that these mutations may affect structural elements involved in the coupling of T3 binding to inhibition of TR DNA binding activity. Analysis of TR x-ray structures revealed that each of these resistance to thyroid hormone syndrome mutations affects a cluster of charged amino acids with potential for ionic bond formation between oppositely charged partners. Two clusters (1 and 2) are adjacent to the dimer surface at the junction of helices 10 and 11. Targeted mutagenesis of residues in Cluster 1 (Arg338, Lys342, Asp351, and Asp355) and Cluster 2 (Arg429, Arg383, and Glu311) confirmed that the clusters are required for stable T3 binding and for optimal TR homodimer formation on DNA but also revealed that different arrangements of charged residues are needed for these effects. We propose that the charge clusters are homodimer-specific extensions of the dimer surface and further that T3 binding promotes specific rearrangements of these surfaces that simultaneously block homodimer formation on DNA and stabilize the bound hormone. Our data yield insight into the way that T3 regulates TR DNA binding activity and also highlight hitherto unsuspected T3-dependent conformational changes in the receptor ligand binding domain.
OBJECTIVE: Leukocyte function-associated antigen-1 (LFA-1) is constitutively expressed on leukocytes, including overexpression on lymphomas and leukemias. We have developed a derivative of BIRT 377, an allosteric inhibitor of LFA-1, which may be chemically tagged without affecting binding. In this study, we modified this derivative, (R)-1-(4-aminobutyl)-5-(4-bromobenzyl)-3-(3,5-dichlorophenyl)-5-methylimidazolidine- 2,4-dione (butylamino-NorBIRT), and demonstrated its potential as a noninvasive imaging agent. METHODS: Specific binding of fluorescein-labeled butylamino-NorBIRT to both human and murine cells was demonstrated using equilibrium binding and dissociation techniques. A radiometal, lutetium-177 (Lu-177), was incorporated into the butylamino-NorBIRT through 1,4,7,10-tetraazacyclododecane-N,N',N",N'''- tetraacetic acid (DOTA) as a chelator. RESULTS: Equilibrium-binding experiments demonstrated that fluorescein- labeled butylamino-NorBIRT specifically binds human and murine LFA-1 with affinity constants of 135 and 186 nM, respectively. Dissociation kinetic experiments demonstrated an off-rate of 0.168/second(1) on murine cells, consistent with the observed affinity constant. Lutetium-177 was used for labeling, with > or =99.99% radiochemical purity and incorporation yield. This radiolabeled derivative exhibited high stability in fetal bovine serum (FBS) at 37 degrees C over 72 hours. (177)Lu-DOTA-butylamino-NorBIRT showed a binding affinity of 235 nM to human LFA-1 for equilibrium binding and competitive binding experiments. CONCLUSIONS: The radiolabeled DOTA-butylamino-NorBIRT may have potential as a noninvasive imaging or therapeutic agent in both human and mouse models.
A glycosidase enzyme with both beta-glucosidase and beta-fucosidase activities has been purified from the seeds of Dalbergia cochinchinensis Pierre (Thai Rosewood) by ammonium sulfate fractionation, preparative isoelectric focusing, and Sephadex G-150 chromatography. The enzyme has molecular weights of 330,000 in the native state and 66,000 in the denatured state. Hydrolysis of p-NP-beta-D-glucoside and p-NP-beta-D -fucoside showed pH optimum at pH 5.0 and was inhibited by delta-gluconolactone, HgCl2, and p-chloromercuribenzoate. The Km and kcat values of the purified enzyme were 5.4 mM and 307 s-1 for p-NP-beta-D-glucoside and 0.54 mM and 151 s-1 for p-NP-beta-D-fucoside, so that the latter had by far the higher kcat/Km ratio. p-NP-beta-D-galactoside, p-NP-beta-D-xyloside, and p-NP-alpha-L-arabinoside were hydrolyzed more slowly. Hydrolysis of sophorose, laminaribiose, and gentiobiose were also rather slow, and hydrolysis of cellobiose was even slower. No hydrolysis of the cyanogenic glucosides linamarin or prunasin, but some hydrolysis of amygdalin and salicin was found. Further studies are required to identify the natural substrates of the enzyme. However, high yields, ease of purification, and storage stability of the enzyme make it a useful candidate for various applications, such as study of oligosaccharide synthesis by reversal of hydrolysis.
BACKGROUND: Epidural morphine yields postoperative pain relief and hemodynamic stability. However, the effects of epidural morphine on sympathetic tone are unclear. This study was designed to elucidate the effects of epidural morphine on cardiac (CSNA) and renal (RSNA) sympathetic nerve activity by direct measurement in anesthetized cats. METHODS: Thirty mongrel cats anesthetized with alpha-chloralose were randomly assigned to one of the following five groups: control (0.2 ml/kg thoracic epidural normal saline; n=5); thoracic epidural morphine (n=9); lumbar epidural morphine (n=6); vagotomized, sinoaortic denervated, thoracic epidural morphine (n=5); or intravenous morphine (n=5). Mean arterial pressure (MAP), heart rate (HR), CSNA, and RSNA were measured 0, 15, 30, 60, 90, and 120 min after saline or morphine (200 microg/kg) administration and 15 min after reversal with 200 microg naloxone given intravenously. RESULTS: In the control group, no changes in measured variables were found after either thoracic epidural saline or intravenous naloxone. Thoracic and lumbar epidural morphine both significantly reduced MAP, HR, CSNA, and RSNA 30 through 120 min after morphine administration (P < 0.05). These changes were reversed by intravenous naloxone. Changes after thoracic epidural morphine administration in vagotomized, baroreceptor-denervated cats were similar to those in intact cats. Intravenous morphine produced no significant changes except for a decrease in MAP, which was reversed by intravenous naloxone. CONCLUSION: In contrast to intravenous morphine, thoracic and lumbar epidural morphine both inhibited cardiac and renal sympathetic nerve activity and consequently reduced MAP and HR in alpha-chloralose anesthetized cats.
STUDY DESIGN: A case of vertebral osteomyelitis secondary to epidural catheter use is reported. OBJECTIVE: To investigate the occurrence of vertebral osteomyelitis after the use of an epidural catheter. SUMMARY OF BACKGROUND DATA: Vertebral osteomyelitis is a rare but serious complication of epidural catheter use that apparently has not been reported previously in orthopedic literature. METHODS: A patient underwent abdominal surgery, and an epidural catheter was used for postoperative pain relief. He presented 3 months later with severe midlumbar pain. Magnetic resonance imaging and microbiologic examination of a specimen obtained at open biopsy were used in the investigation. RESULTS: Magnetic resonance imaging suggested vertebral osteomyelitis involving L1-L3. The patient underwent open debridement and posterior instrument stabilization. Biopsies taken from L3 pedicles yielded Pseudomonas aeruginosa, which had been recovered earlier from the epidural catheter tip. CONCLUSION: Vertebral osteomyelitis is a rare but serious complication of epidural catheter use.
The alterations in chloroplast phospholipid acyl chain composition and phospholipid molecular species composition of Dunaliella salina (UTEX 1644) were monitored during acclimation to low temperature. Chlorophyll fluorescence yield, an indicator of chloroplast membrane stability, was used as a physical means of following the acclimation process.Minor alterations in phospholipid acyl chain composition were evident within 36 hours of shifting the cells from 30 to 12 degrees C. Between 36 and 60 hours, pronounced changes in the acyl chain composition of phosphatidylglycerol (PG) were observed. Changes in the acyl chain composition of phosphatidylcholine (PC) did not occur until sometime after 60 hours.Alterations in the phospholipid molecular species during acclimation were also examined. The pattern of change observed in PC molecular species, namely a decrease in species having one saturated chain (16:0) paired with a C(18) acyl chain and a concomitant increase in species having two unsaturated C(18) acyl chains, suggests that molecular species changes augment fatty acid compositional changes as a mean of adapting to low temperature. The molecular species of PG were found to change abruptly between 36 and 60 hours following a shift to low temperature. During this time, a dramatic alteration in the threshold temperature of thermal denaturation of the photosynthetic apparatus, as measured by chlorophyll fluorescence, also occurred. Lipid compositional changes other than those associated with PG were negligible during this time. This strongly suggests that a correlation exists between the molecular species composition of PG and the thermal stability of the photosynthetic membrane.
Mutants of Arabidopsis thaliana deficient in plastid glycerol-3-phosphate acyltransferase activity have altered chloroplast membrane lipid composition. This caused an increase in the number of regions of appressed membrane per chloroplast and a decrease in the average number of thylakoid membranes in the appressed regions. The net effect was a significant decrease in the ratio of appressed to nonappressed membranes. A comparison of 77 K fluorescence emission spectra of thylakoid membranes from the mutant and wild type indicated that the ultrastructural changes were associated with an altered distribution of excitation energy transfer from antenna chlorophyll to photosystem II and photosystem I in the mutant. The changes in leaf lipid composition did not significantly affect growth or development of the mutant under standard conditions. However, at temperatures above 28 degrees C the mutant grew slightly more rapidly than the wild type, and measurements of temperature-induced fluorescence yield enhancement suggested an increased thermal stability of the photosynthetic apparatus of the mutant. These effects are consistent with other evidence suggesting that membrane lipid composition is an important determinant of chloroplast structure but has relatively minor direct effects on the function of the membrane proteins associated with photosynthetic electron transport.
The DNA-stimulated 75000-Mr ATPase described in the preceding paper is shown to be a further catalytic DNA unwinding principle (DNA unwinding enzyme II) made in Escherichia coli cells (the first being the 180000-Mr ATPase of the cells: DNA unwinding enzyme I). Unwinding depends strictly, on the supply of ATP. It occurs only under conditions permitting ATP dephosphorylation and it proceeds as long as enzyme molecules are permitted to enter the enzyme - DNA complex. The enzyme binds specifically to single-stranded DNA yielding a complex of only limited stability. These results are interpreted in terms of a distributive mode of action of the enzyme. It is argued that chain separation starts near a single-stranded DNA region and that, forced by continued adsorption of enzyme molecules to the DNA, it develops along the duplex. This mechanism is different from that deduced previously for DNA unwinding enzyme I. Complicated results were obtained using ATPase prepared from rep3 mutant cells.
Herpes simplex virus strain MPdk(-) multiplies in HEp-2 cells, but not in dog kidney (DK) cells. Strain MPdk(+)sp, a multistep mutant of MPdk(-), multiplies in both HEp-2 and DK cells. Stabilized lysates of productively infected cells yield three macromolecular aggregates of viral deoxyribonucleic acid and protein banding in CsCl gradients at densities of 1.285 g/cm(3) (alpha), 1.325 g/cm(3) (beta), and 1.37 to 1.45 g/cm(3) (gamma). Similar lysates from abortively infected cells yield only the beta and gamma bands. Electron microscopic examination revealed that (i) the alpha band contained enveloped nucleocapsids, whereas the beta band contained naked nucleocapsids and particles tentatively identified as internal components of the nucleocapsids, and that (ii) the enveloped virions and reduplication of cellular membranes observed in thin sections of productively infected cells were absent from abortively infected cells. Studies of the surface antigens of infected cells in a cytolytic system described previously revealed that abortively infected cells contained approximately 10-fold less virus-induced surface antigen than did productively infected cells. From these and other data published previously, we concluded that infectious MPdk(-) virions are not made in DK cells because (i) functional viral products necessary for the envelopment of the nucleocapsid are not made, and (ii) capsid proteins and some nonstructural products specified by the virus malfunction.
The central region of the matrix protein p17 of HIV-1 is known to be essential during virus assembly. We substituted alanines for amino acid triplets in this region of p17 (amino acid residues 47 to 55: NPG LLE TSE). Introduction of the respective mutations into the gag-coding sequence of HI-proviruses and subsequent transfection into Cos-7 cells led to particle production and release. Exchange of LLE resulted in the production of non-infectious particles. These residues may be important for correct folding and assembly of the processed matrix protein and the production of infectious HIV. In vitro studies of wild-type and mutated matrix proteins using spectroscopic methods (NMR, fluorescence, CD) yielded detailed data about structure and stability. Two-dimensional NMR spectroscopy showed that wild-type and mutant proteins (p17-NPG and p17-TSE) are well folded. Besides structural changes at the mutated site, chemical shift changes indicate small but significant long range structural rearrangements. The stability against chemically and thermally induced unfolding of the mutants p17-NPG and p17-TSE was slightly decreased, while that of p17-LLE was drastically diminished. The alterations have only a local effect on protein folding for the mutants p17-NPG and p17-TSE, and the globular tertiary structure remains nearly unchanged. For p17-LLE, however, the substitutions seem to trigger significant changes in structural elements.
BACKGROUND: The purpose of this study of distal radial fractures was to compare the radiographic and clinical results after use of a standard four-pin external fixator with those after use of a five-pin fixator with the fifth pin stabilizing the distal radial articular fragment. METHODS: In an open prospective trial, fifty patients with an unstable distal radial fracture were randomized for treatment with closed reduction and either a standard small Association for the Study of Internal Fixation (ASIF) four-pin fixator (twenty-five patients) or a five-pin external fixator (twenty-five patients). The fixators were removed at nine weeks, and all patients were assessed radiographically and clinically at six months. RESULTS: Follow-up radiographs demonstrated significantly less loss of alignment and length with the five-pin external fixator. Pin site infections were more prevalent with the four-pin fixator. The range of motion of the wrist and forearm, the grip strength, and the Lidstrom functional ratings at six months were all significantly better after use of the five-pin fixator. CONCLUSIONS: The use of a five-pin external fixator, with the fifth pin stabilizing the distal radial articular fragment, yields better radiographic and functional results than does a four-pin fixator.
This report describes a 13-year-old boy who had high fever with severe pancytopenia and acute psychosis as initial presentation. Bone marrow examination was compatible with infection-associated hemophagocytic syndrome (IAHS). Blood culture showed no growth of bacteria while the culture of bone marrow yielded Salmonella typhi. The clinical condition stabilized shortly after the use of ceftriaxone. This case illustrates that typhoid fever must be included in the differential diagnosis of IAHS. In cases with IAHS, bacterial culture as well as morphological study of bone marrow is necessary for the evaluation of etiological agent and to avoid injudicious use of chemotherapy.
Fifteen patients who had undergone aortic reconstructions were examined. Hemorheologic studies were performed at the following stagest initial anesthesia, the end of operation, the early postoperative period, and the 2nd-3rd days after operation. A study was made of blood viscosity at a shift rate 5-300 s(-1), of suspension stability, caisson viscosity (CV), and the yield stress (YS). The back light diffusion intensity was recorded on the erythroaggregometer ADE=5 (Russia) to evaluate the time of linear aggregate formation (T(1)), the time of three-dimensional aggregate formation (T(2)), characteristics of the end size of the aggregates (Ampl), total hydrodynamic strength of the aggregates (Beta), strength index of especially large aggregates (Ia((2,5))). The index of erythrocyte aggregation (IEA) and the index of erythrocyte deformation (IED) were also computed. Initially, the normal blood viscosity values were marked. However, in the early postoperative period, their values returned to the preoperative level. In patients with complications, blood viscosity appreciably rose, exceeding the preoperative parameters. At the end of operation there was a decrease in erythrocyte aggregation, especially due to the TT(1) and Ampl rise, while beta dropped. In the postoperative period, patients without complications demonstrated the growth of erythrocyte aggregation but Ampl of cell aggregation diminished. In the postoperative period, patients with complications showed a considerable intensification of erythrocyte aggregation due to the rise of Ampl, Beta and Ia((2,5)). Toward the end of operation a decrease of plasma viscosity was revealed in the presence of GV rise. In the postoperative period, patients with complications demonstrated the growth of plasma viscosity concurrently with CV lowering. Toward the end of operation the YS increased. However, in patients with the uncomplicated postoperative period, the magnitude of this parameter dropped and reached permissible values in the given patient group whereas in patients with complications, the YS remained significantly high.
A giant solitary osteochondroma of the proximal humerus in a 9-year-old boy was widely resected. Reconstruction of the bone defect was achieved with two nonvascularized fibula segments which gave sufficient stability to the proximal humerus and yielded rapid bone remodeling into an almost normal cortical bone after six months.