Acute toxicity of 33 herbicides to the green alga Chlorella pyrenoidosa.
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Chlorella↗
Biomedical subjects
J Lu
Publications and source records attributed to J Lu.
Effects of extrinsic imidazole ligation on the molecular and electronic structure of cytochrome c.
Although imidazole ligand binding to cytochrome c is not directly related to its physiological function, it has the potential to provide valuable information on the molecular and electronic structure of the protein. The solution structure of the imidazole adduct of oxidized horse heart cytochrome c (Im-cyt c) has been determined through 2D NMR spectroscopy. The Im-cyt c, 8 mM in 1.2 M imidazole solution at pH 5.7 and 313 K, provided altogether 2,542 NOEs (1,901 meaningful NOEs) and 194 pseudocontact shifts. The 35 conformers of the family show the RMSD values to the average structure of 0.063+/-0.007 nm for the backbone and 0.107+/-0.007 nm for all heavy atoms, respectively. The characterization of Im-cyt c is discussed in detail both in terms of structure and electronic properties. The replacement of the axial ligand Met80 with the exogenous imidazole ligand induces significant conformation changes in both backbone and side chains of the residues located in the distal axial ligand regions. The imidazole ligand binds essentially parallel to the imidazole of the proximal histidine, the two planes forming an angle of 8+/-7 degrees. The electron delocalization on the heme moiety and the magnetic susceptibility tensor are consistent with these structural features.
Amino Acid Sequence↗
Effect of five flavonoid compounds isolated from Quercus dentata Thunb on superoxide generation in human neutrophils and phosphorylation of neutrophil proteins.
Effect of five yellow compounds isolated from Quercus dentata on superoxide generation and protein phosphorylation in human neutrophils was investigated. The five yellow compounds examined were Kaempferol 3-O-beta-D-glucopyranoside (B), quercetin 3-O-beta-D-glucopyranoside (DA), Kaempferol 3-O-(6"-trans-p-coumaroyl)-beta-D-glucopyranoside (D1), Kaempferol 3-O-(2"-6"-di-trans-p-coumaroyl)-beta-D-glucopyranoside (D7) and Kaempferol 3-O-(2",4"-di-acetyl-3"-cis-p-coumaroyl-6"-trans-p-coumaroyl)-beta-D-glucopyranoside (A). D7 suppressed significantly the superoxide generation induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP). D1 and DA suppressed significantly the superoxide generation induced by arachidonic acid (AA). However, the superoxide generation induced by phorbol 12-myristate 13-acetate (PMA) was suppressed by all yellow compounds. When the cells were incubated with fMLP and D7, the tyrosyl phosphorylation of 67, 60, 58 and 38 kDa proteins of the cells was markedly decreased in a concentration-dependent manner.
Flavonoids↗
Is there evidence for preferential delivery of ovarian estradiol to the endometrium?
OBJECTIVE: To determine the direction of delivery of E(2) in the female pelvis by assessing the ratio of endometrial to serum E(2) in women whose ovaries were stimulated to produce E(2) with women who received exogenous E(2). DESIGN: Prospective comparative study. SETTING: University-based ART program. PATIENT(S): Oocyte donors and recipients of donor oocytes. INTERVENTION(S): Micronized E(2) administered by the oral or vaginal route and oocyte donation. MAIN OUTCOME MEASURE(S): Serum and endometrial levels of E(2). RESULT(S): Serum E(2) levels were significantly higher in women who underwent controlled ovarian hyperstimulation (COH) and women receiving exogenous E(2) by the vaginal route than in those who received oral E(2). Levels of E(2) in endometrial tissue were similar in women who underwent COH and those receiving oral E(2). Endometrial E(2) levels in women who underwent vaginal administration were significantly higher than those in the oral E(2) or COH groups. The ratio of endometrial to serum E(2) was highest in women who underwent vaginal E(2) and lowest in those undergoing COH. CONCLUSION(S): Vaginal administration of micronized E(2) results in preferential absorption of E(2) into the endometrium, consistent with a "uterine first pass" effect. Since endogenous E(2) produced the smallest ratio of E(2) between the endometrium and serum, E(2) produced by the ovaries is not preferentially delivered to the uterus.
Administration, Oral↗
Variation of ER status between primary and metastatic breast cancer and relationship to p53 expression*.
OBJECTIVE: Estrogen-dependent growth of breast cancer can be blocked by anti-estrogens. Estrogen receptor (ER) presence in breast cancer implies responsiveness to endocrine therapy. However, for those patients who ultimately develop resistance to endocrine therapy, the mechanisms remain unclear. The present study attempted to compare the expression status of ER mRNA in a series of primary breast tumors with matched metastases and explored the relation between ER and mutant p53 expression. METHODS: In situ hybridization using a digoxigenin-labeled estrogen receptor cDNA probe was employed to determine the expression of ER mRNA in 52 cases of primary tumors and their matched axillary lymph node metastases. Immunohistochemical staining using a monoclonal antibody against ER was also performed. RESULTS: ER expression was observed in 53.8% (28/52) of primary tumors and 48% (25/52) of metastases, while 57.7% (30/52) of primary tumors and 53.8% (28/52) of metastases showed ER mRNA positivity. There were variations in ER status between in situ hybridization and immunohistochemistry measurements and between primary tumors and metastases. Mutant p53 expression was inversely associated with ER-negative, high-grade tumors. CONCLUSIONS: In situ hybridization may be a more specific and sensitive method for determination of ER status than immunohistochemistry. It is possible that the biologic properties of ER change, and these changes may influence tumor response to endocrine therapy. In view of the ER variation, it was suggested that the ER status of metastatic tumors in addition to primary tumors should be taken into consideration in order to better determine the benefit of clinical endocrine therapy.
Breast Neoplasms↗
Small primary sensory neurons innervating epidermis and viscera display differential phenotype in the adult rat.
Target tissues contribute to the phenotype and function of sensory neurons. Due to lack of appropriate markers for trkA expressing sensory axons and terminals, the detailed peripheral projection of these neurons is unclear. In this study, the peripheral projections of trkA immunoreactive neurons are characterized using the combined techniques of immunohistochemistry and retrograde tracing. We found approximately 65% of all neurons projecting to the adrenal gland and kidney are trkA immunoreactive, whereas 6, 14 and 37% of neurons innervating whisker follicle, epidermis and footpad, respectively, are immunoreactive for trkA. A low proportion of trkA immunoreactive neurons innervating epidermis indicates that the majority of sensory neurons innervating epidermis are independent of trkA signalling for their normal function. We further investigated whether these epidermal projecting neurons can bind isolectin IB4. We found approximately 70% of all neurons innervating epidermis are IB4 binding neurons, but they did not express trkA. Thus, NGF sensitive neurons primarily project to viscera but not epidermis or other skin structures, whereas IB-4 positive neurons primarily project to epidermis in the adult rat.
Adrenal Glands↗
Localization of the K(+)-Cl(-) cotransporter, KCC3, in the central and peripheral nervous systems: expression in the choroid plexus, large neurons and white matter tracts.
Na(+)-independent K(+)-Cl(-) cotransporters function in the regulation of cell volume, control of CNS excitability and epithelial ion transport. Several K(+)-Cl(-) cotransporter isoforms are expressed in the nervous system, and KCC3 in particular is expressed at significant levels in both the brain and spinal cord. The cellular localization of this transporter has, however, not been determined. In this study, we generated a polyclonal antibody against the KCC3 cotransporter in order to characterize and localize this protein in the brain. Western blot analysis of mouse kidney and brain demonstrated KCC3 proteins of different size, 150 and 170kDa, respectively; this disparity remained after deglycosylation. Northern blot confirmed the presence of two distinct forms of KCC3, KCC3a and KCC3b, generated by the inclusion of different first coding exons. KCC3a predominates in the brain, whereas KCC3b is more abundant in the kidney. Western blots with membrane protein from dissected mouse brain revealed abundant expression in all brain regions examined: the cerebral cortex, hippocampus, diencephalon, brainstem and cerebellum. The spinal cord showed the highest levels of KCC3 expression, whereas peripheral nerves did not contain immunoreactive KCC3 protein. Western blot analysis of whole brain from rats of various ages indicated increasing expression in the postnatal period, concurrent with CNS maturation and myelination. Immunofluorescence studies demonstrated strong signal in myelinated tracts of the spinal cord, consistent with individual myelin sheaths. Brain sections also showed white matter enhancement, but also cellular signal consistent with pyramidal neurons and Purkinje cells. The base of the choroid plexus epithelium was also strongly labeled. These data demonstrate the specificity and diversity of KCC3 expression in the mouse CNS.
Amino Acid Sequence↗
A pyridone analogue of traditional cannabinoids. A new class of selective ligands for the CB(2) receptor.
A pyridone analogue (5) of the potent bicyclic cannabinoid CP 47,497 (6) has been synthesized as a model for one conformational isomer of anandamide and to test the hypothesis that an amide carbonyl may serve as a hydrogen bond acceptor in interactions with the CB(1) cannabinoid receptor. Pyridone 5 was synthesized from 6-bromo-2-methoxypyridine (10) by palladium catalyzed coupling with 1-pentyne to provide 11. Catalytic hydrogenation of 11 and hydrolysis to pyridone 13 followed by N-alkylation gave 1-propyl-6-pentyl-2-pyridone (15). Bromination of 15 gave dibromide 18, which underwent Heck coupling with cyclohex-2-en-1-one to give enone 19. Catalytic hydrogenation of 19 gave ketone 20 which was reduced using NaBH(4) to alcohol 5. Reduction of 20 with K-Selectride gave the axial epimer of 5 (21). Neither alcohol 5 nor 21 have significant affinity for the CB(1) receptor (K(i) > 970 nM), but both have moderately high affinity for the CB(2) receptor (K(i) < 60 nM).
Analgesics↗
Preventing of chylothorax after oesophagectomy by routine pre-operative administration of oral cream.
The anatomy of the thoracic duct varies considerably. This can make it difficult to locate during oesophageal surgery, especially in the fasted patient. We describe the technique of administering cream orally before primary oesophageal surgery, to aid in the identification of the thoracic duct. The duct along with other lymphatic channels can then be ligated as appropriate, helping to reduce the incidence of post-operative chylothorax.
Administration, Oral↗
Ontogenetic changes in enzyme activities associated with energy production in the spiny lobster, Jasus edwardsii.
The larval life of the spiny lobster Jasus edwardsii is one of the longest and most complex of any marine organism and is poorly understood due to the difficulty of studying cryptic, pelagic organisms. Hence, the capacity for active swimming in the phyllosoma, puerulus and juvenile stages and the use of possible metabolic fuel reserves was inferred from a number of enzyme activities, including citrate synthase, lactate dehydrogenase, and HOAD. High activities of CS and LDH in abdominal tissues of Stage 11 phyllosoma and pueruli are consistent with a capacity to commence active on-shore movement. The activities of LDH and HOAD showed positive allometry while CS was independent of body mass. The body mass dependence of LDH activity may reflect the developing ability of the lobster to initiate brief escape manoeuvres, and the scaling of HOAD reflects an increased use of lipid fuel reserves. Aerobic enzyme activities were higher in abdominal tissues than in cephalic tissues of pelagic pueruli, but high activities appear in the cephalic tissues of juveniles. These changes mirror a developmental shift in activity from pelagic oceanic swimming to a benthic existence on the seabed of the near shore. The low LDH activity in pueruli confirmed previous findings that they have limited feeding capacity, with carbohydrate contributing little towards the major energy reserves. The highest LDH activities occur in the abdominal muscles of juveniles and correlate with rapid tail-flicking escape behaviour. The activities of HOAD increased throughout development, and in the abdominal tissues of juveniles, may reflect lipid transformation and accumulation as an energy reserve. Enzyme activities, therefore, provide useful information concerning migratory behaviour that is presently unavailable from ecological studies.
Animals↗
Ion solvation and association in LiClO4/sulfolane solution: a vibrational spectroscopic and molecular orbital study.
Solvation interaction and ion association in solutions of lithium perchlorate/sulfolane have been studied by using infrared and Raman spectra as a function of concentration of lithium perchlorate. The band changes of antisymmetric OSO stretch, antisymmetric CSC stretch, -SO2 wag and twist suggest that there is an interaction between Li+ and sulfolane molecules, and the site of solvation is the oxygen atom of -SO2 group. The molecular orbital calculation supports this suggestion. On the other hand, the apparent solvation number was calculated, and the band fitting for the ClO4- band reveals the presence of contact ion pair, solvent separated ion pair and free ClO4- anion in the concentrated solutions.
Electrolytes↗
A quantitative assay of telomerase activity.
PURPOSE: Telomerase is a ribonucleoprotein that extends telomeres at the ends of chromosome. Increased telomerase activity is associated with cellular immortality. The currently available assay for telomerase, i.e., telomeric repeat amplification protocol (TRAP), consists of 2 steps: (a) telomerase-mediated extension of an oligonucleotide primer by the enzyme-containing extracts of cells and tissues, and (b) amplification of the telomerase-extended primer products by polymerase chain reaction (PCR) and detection of the PCR products. It is generally accepted that the current TRAP assay lacks quantitative precision. The present study was to develop a quantitative telomerase assay with greater precision and sensitivity. METHODS: This new method used the primer extension method as in TRAP, plus the following modifications: (a) used a lysis buffer that yielded complete lysis of nuclei; (b) removal of PCR inhibitors by phenol/chloroform extraction after primer extension; and (c) used primers for the internal standard that were designed to reduce their competition with the telomerase products for PCR. RESULTS: The modified method showed a good correlation (r2 = 0.99, P < 0.001) between telomerase amount (expressed as total protein in cell lysate) and its activity (expressed as telomerase products). Compared to the conventional TRAP, the new method (a) was more sensitive (average of 5.5-fold in cultured cancer cells and >5.9-fold in patient tumors), (b) had a lower inter- and intra-day variability (>3fold), and (c) showed a 2 to 4-fold broader range of linearity in the standard curve. The higher assay sensitivity further enabled the use of a nonradioactive method, i.e., ethidium bromide staining of DNA, to detect the TRAP products, as opposed to the use of radioactive nucleotide and the more labor-intensive autoradiography mandated by the conventional TRAP. CONCLUSION: We report here a quantitative assay for telomerase activity in cultured human cancer cells and patient tumors.
Biological Assay↗
Selecting reliable pharmacokinetic data for explanatory analyses of clinical trials in the presence of possible noncompliance.
For single-dose concentration-time data collected in clinical trials to be useful for explanatory pharmacokinetic (PK) or pharmacokinetic-pharmacodynamic (PK-PD) analyses, the following two assumptions on the data must hold: (i) the times of the concentration (PK) observations are known, and (ii) the patient's recent past dosing history (times and amounts) is known. If either (or both) of these assumptions does not hold, and data analysis proceeds as if it did, biased estimates may result. Assumption (i) usually does hold as study personnel observe and record PK sampling times. Assumption (ii) is a problem when, as is often the case of outpatient studies, one must rely on patient recall for past dosing history. This paper presents a technique to avoid assumption (ii) by identifying for deletion those PK observation occasions likely exhibiting unreliable preceding dose histories. To so identify occasions, a Bayes objective function (posterior density) for the data is maximized in its parameters for each individual. The likelihood factor of this function is a mixture pharmacostatistical model expressing the likelihood of the observed concentration(s) under three mutually exclusive events: the prescribed dose preceding the occasion was not taken at all (NT), the prescribed dose was taken at the specified time (T), or the prescribed dose was taken at an unspecified time (U). Suspect observations are identified as those whose maximum corresponding likelihood component is other than T. The approach as defined here relies on the following assumptions in addition to (i): (ii) population PK (i.e., the distribution of PK parameters in the population being sampled) is known, at least approximately. (iii) PK samples (at least 1 or 2 per occasion) are available, (iv) doses taken are of the stated magnitude, and (v) the drug has a short half-life. Simulations reveal that especially when more than one PK sample is available per study occasion, the methodology chooses a set of PK observations that should perform better in subsequent explanatory analyses, or as a basis for estimating individual PK parameters, than do other simpler methods.
Clinical Trials as Topic↗
Melanopsin in cells of origin of the retinohypothalamic tract.
All known eukaryotic organisms exhibit physiological and behavioral rhythms termed circadian rhythms that cycle with a near-24-hour period; in mammals, light is the most potent stimulus for entraining endogenous rhythms to the daily light cycle. Photic information is transmitted via the retinohypothalamic tract (RHT) to the suprachiasmatic nucleus (SCN) in the hypothalamus, where circadian rhythms are generated, but the retinal photopigment that mediates circadian entrainment has remained elusive. Here we show that most retinal ganglion cells (RGCs) that project to the SCN express the photopigment melanopsin.
Animals↗
Preparation of microporous aluminium anodic oxide film modified Pt nano array electrode and application in direct measurement of nitric oxide release from myocardial cells.
A novel method for fabricating a nano array electrode (NAE) by using micropores of aluminium anodic film as templates was investigated. To evaluate the NAE, cyclic scanning of NAE in Fe(CN)6(3-) solution was performed and a sigmoidal shaped voltammogram was obtained. The NAE was designed to measure nitric oxide (NO) in vitro and in vivo. Studies showed that it was a sensitive and selective NO electrochemical sensor. NO release from myocardial cells was directly measured with this NAE and the results were satisfactory.
Aluminum Oxide↗
The effect of KSCN on the partition of proteins in polyethylene glycol/(NH4)2SO4 aqueous two-phase system.
The effect of potassium thiocyanate on the partitioning of lysozyme and BSA in polyethylene glycol 2000/ammonium sulfate aqueous two-phase system has been investigated. As a result of the addition of potassium thiocyanate to the PEG/ammonium sulfate system, the PEG/mixed salts aqueous two-phase system was formed. It was found that the potassium thiocyanate could alter the pH difference between the two phases, and, thus, influence the partition coefficients of the differently charged proteins. The relationship between partition coefficient of the proteins and pH difference between two phases has been discussed. It was proposed that the pH difference between two phases could be employed as the measurement of electrostatic driving force for the partitioning of charged proteins in polyethylene 2000/ammonium sulfate aqueous two-phase system.
Ammonium Sulfate↗
A simplified method for large scale quantification of transcriptional activity and its use in studies of steroids and steroid receptors.
Chloramphenicol acetyltransferase (CAT) is widely used as a reporter to determine the transcriptional specificity of promoters and for the quantification of transcriptional activity of transcription factors such as nuclear receptors. However, large-scale quantification of CAT activity in transfected mammalian cells is still heavily labor-intensive, time-consuming and expensive. Here, we describe a simplified method that combined using multiwell tissue culture plates in transfection and sample preparation and a modified single step method for quantitatively assaying CAT activity. By using multiwell plates, the tedious sample preparation procedure was dramatically simplified. The CAT assay is performed by mixing cell lysate, chloramphenicol, 3H-acetyl co-enzyme A and non-aqueous scintillation fluid in scintillation vials, followed by automatically continuously counting samples two or three cycles at fixed time intervals. The catalytic reaction and determination of CAT activity are carried out in the vials simultaneously. This simplified protocol is faster, less expensive and more accurate than other CAT assay procedures and the results can be normalized easily. The utility of the assay is demonstrated by the analysis of the transcriptional activity of the glucocorticoid and androgen receptors cotransfected into cells with a CAT reporter.
Animals↗
Cellular inflammatory response associated with breakdown of the blood-brain barrier after closed head injury in rats.
This study reports a widespread microglial response characterized by an upregulation of surface antigens, such as complement type 3 receptors (CR3) and major histocompatibility complex (MHC) class II antigens on these cells following closed head injury. Increased expression of CR3 (OX-42) and MHC class II antigens (OX-6) was observed in rats killed at 1, 3, and 5 days after injury. Intense OX-42 immunoreactivity was observed in microglial cells throughout the brain with a smaller number of them being OX-6 positive. In addition to microglial reaction, astrocytic activation reflected in cellular hypertrophy and increased immunoreactivity for glial fibrillary acidic protein (GFAP) was observed at 5 days after head injury. Together with the above, a diffuse perivascular and intraneuronal immunostaining for immunoglobulin G (IgG) was observed primarily in the cerebral cortex. This was accompanied by an enhanced expression of both endothelial nitric oxide synthase (eNOS) in blood vessels and inducible nitric oxide synthase (iNOS) in brain macrophages. In rats subjected to closed head injury followed by a single intraperitoneal (i.p.) injection of rhodamine isothiocyanate (RhIc), seepage of the fluorescent dye into the neuropil was observed. This had resulted in the labelling of the cortical neurons clearly demonstrating a breakdown of the blood-brain barrier (BBB). In the latter, it is conceivable that the ensuing leakage of plasma immunoglobulins and other serum-derived materials could induce the expression of MHC class II antigens on microglia. The mechanism causing the BBB dysfunction is not clear, although present results suggest that excessive release of nitric oxide (NO) may be a contributory factor. The widespread activation of microglia in rats after head injury suggests their involvement in increased endocytosis and immunological responses.
Animals↗