ABSTRACT
In Asian rice systems, Cyrtorhinus lividipennis Reuter is an important predator that preys on rice planthopper eggs and young nymphs, as a primary food source. Alanine aminotransferase (ALT) acts in many physiological and biochemical processes in insects. We cloned the full-length complementary DNA of C. lividipennis ClALT. Expression analysis showed higher expression in the fat body and midgut compared to other tissues. It is expressed in all C. lividipennis developmental stages and at least four organs. Silencing of ClALT by RNA interference significantly decreased the ClALT enzyme activity and ClALT expression compared to dsGFP-treated controls at 2 days after emergence (DAE). Silencing of ClALT influenced free hemolymph amino acid compositions, resulting in a reduction of Aspartic acid (Asp) and Alanine (Ala) proportions, and increased Cysteine (Cys) and Valine (Val) proportions in females at 2 DAE. dsClALT treatments led to decreased soluble total protein concentrations in ovary and fat body, and to lower reduced vitellogenin (Vg) expression, body weight, and the numbers of laid eggs. The double-stranded RNA viruse treatments also led to prolonged preoviposition periods and hindered ovarian development. Western blot analysis indicated that silencing ClALT also led to reduced fat body Vg protein abundance at 2 DAE. These data support our hypothesis that ClALT influences amino acid metabolism and fecundity in C. lividipennis.
Subject(s)
Alanine Transaminase , Amino Acids/metabolism , Fertility , Heteroptera , Alanine Transaminase/genetics , Alanine Transaminase/metabolism , Amino Acids/genetics , Animals , Hemolymph/metabolism , Heteroptera/genetics , Heteroptera/metabolism , Heteroptera/physiology , Insect Proteins/metabolism , RNA Interference , Vitellogenins/metabolismABSTRACT
The rising prevalence of antibiotic resistance underscores the urgent need for novel antimicrobial agents. Antimicrobial peptides (AMPs) are potentially effective therapeutics that disrupt bacterial membranes regardless of resistance to traditional antibiotics. We have developed engineered cationic AMPs (eCAPs) with broad activity against multidrug-resistant (MDR) bacteria, but stability remains an important concern. Therefore, we sought to enhance the clinical utility of eCAP WLBU2 in biological matrices relevant to respiratory infection. A designed substitution of d-Val for l-Val resulted in increased resistance to protease enzymatic degradation. We observed multiple gains of functions such as higher activity against bacteria in biofilm mode of growth, significantly lower toxicity to erythrocytes and white blood cells compared to WLBU2, with increased safety in mice. Direct airway delivery revealed a therapeutic index of >140 for the selected enantiomer compared to that of <35 for WLBU2. The data warrant clinical exploration by aerosolized delivery to mitigate MDR-related respiratory infection.
Subject(s)
Anti-Bacterial Agents , Antimicrobial Cationic Peptides , Bacteria , Respiratory Tract Infections , Animals , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Antimicrobial Cationic Peptides/pharmacology , Antimicrobial Cationic Peptides/therapeutic use , Bacteria/drug effects , Bacteria/metabolism , Drug Resistance, Multiple, Bacterial , Mice , Microbial Sensitivity Tests , Protein Engineering , Therapeutic IndexABSTRACT
Objective: To investigate the effects of Yiqi Huatan Quyu prescription on oxidative stress and pathological changes in chronic intermittent hypoxia rats liver. Methods: A total of 24 male SD rats aged eight weeks were randomly divided into 3 groups by the random number table: normal control group (NC), chronic intermittent hypoxia group (CIH) and chronic intermittent hypoxia plus Yiqi Huatan Quyu prescription supplement group (Chinese medicine group, CM)(n=8 each). The CIH group and CIHN group were exposed to intermittent hypoxia every day for 8 consecutive weeks. In addition, the CIHN group received Yiqi Huatan Quyu prescription via gavage 30 min before the CIH. Eight weeks later, serums were collected to test alanine aminotransferase (ALT) and aspartate aminotransferase (AST) level. Meanwhile, rat livers were extracted to evaluate malondialdehyde (MDA), total superoxide dismutase (T-SOD), glutathione (GSH) and Nuclear factor κB (NF-κB) and observe the pathological changes of liver. Results: The levels of serum ALT and AST in the CIH group were significantly higher than those of NC group[(112.1±31.7) vs (41.3±6.6) U/L, (295.4±39.8) vs (104.5±12.3) U/L], the contents of the MDA and NF-κB in the CIH group were notably higher than those of NC group[(7.9±1.1) vs (3.6±0.7) nmol/mgprot, (16.2±3.3) vs (5.7±2.2) ng/L], the activities of T-SOD and GSH in the CIH group were significantly lower than those of control group[(181.6±28.6) vs (304.3±42.9) U/mgprot, (5.5±1.3) vs (14.9±2.4) mg/gprot](all P<0.001). The levels of the serum ALT and AST in CM group were significantly lower than those of CIH group[(52.2±8.6) vs (112.1±31.7) U/L, (148.1±20.4) vs (295.4±39.8) U/L], the contents of liver MDA in CM group was notably lower than those of CIH group[(4.5±0.7) vs (7.9±1.1) nmol/mgprot], the activities of liver T-SOD and GSH in CM group were significantly higher than those of CIH group[(226.9±38.9) vs (181.6±28.6) U/mgprot, (10.3±1.7) vs (5.5±1.3) mg/gprot](all P<0.05). Compared with CIH group, declining tendency was observed from contents of NF-κB in CM group, but there was no statistical difference[(15.8±2.1) vs (16.2±3.3) ng/L, P>0.05]. Pathology observation showed the CIH group had abundant inflammatory cells infiltration in the liver portal area and the inflammatory cells infiltration decreased following Chinese medicine treatments. Conclusion: Yiqi Huatan Quyu prescription has some protection to CIH rat liver, which might mediate by the reduction of oxidative stress and inflammatory mediator.
Subject(s)
Drugs, Chinese Herbal , Hypoxia , Oxidative Stress , Alanine Transaminase , Animals , Aspartate Aminotransferases , Glutathione , Liver , Male , Malondialdehyde , NF-kappa B , Oxidation-Reduction , Rats , Rats, Sprague-Dawley , Superoxide DismutaseSubject(s)
Cyclooxygenase 2/metabolism , Drugs, Chinese Herbal/therapeutic use , Epidermis/radiation effects , Glucosides/therapeutic use , Radiation Injuries, Experimental/drug therapy , Reactive Oxygen Species/metabolism , Stilbenes/therapeutic use , Animals , Humans , Mice , Mice, Inbred BALB C , Radiation Injuries, Experimental/enzymology , Sunscreening Agents/therapeutic use , Ultraviolet Rays/adverse effectsABSTRACT
AIMS: To increase the fruit body production of Cordyceps guangdongensis, selected cultivation conditions, especially nutritional parameters were optimized. METHODS AND RESULTS: Cordyceps guangdongensis was inoculated on potato dextrose agar slants with pH values from 4.5 to 9.0 and cultivated in artificial media with different carbon and nitrogen supplements. Primordium formation in C. guangdongensis was favoured by slightly acidic conditions. Fruit body yields and biological efficiency (BE) recorded were all highest in cultures of C. guangdongensis supplemented with sucrose and KNO3 as carbon and nitrogen supplements, respectively. Highest fruit body yields and BE values were recorded with C : N ratio of 12 : 1. The optimal medium consisted of (g l(-1)) 20.0 sucrose, 4.0 soya bean powder, 5.0 beef extract and 10.0 KNO3. Cultivation experiments using this medium confirmed its reliability; 18.35% of BE was obtained, compared with a calculated maximum BE of 18.65% based on orthogonal test data. CONCLUSIONS: Cordyceps guangdongensis preferred sucrose and potassium nitrate as best carbon and nitrogen supplements. It produced satisfying yield of fruit body with optimized medium. SIGNIFICANCE AND IMPACT OF THE STUDY: Optimized artificial cultivation conditions could promote the yield of C. guangdongensis and decreased the cost of production.
Subject(s)
Cordyceps/cytology , Cordyceps/isolation & purification , Mycology/methods , Carbon/metabolism , Cordyceps/growth & development , Culture Media/chemistry , Hydrogen-Ion Concentration , Nitrogen/metabolismABSTRACT
Chronic myeloid leukaemia (CML) is characterized by t(9;22)(q34;q11) and the aberrant expression of the fusion protein Bcr-Abl that leads to constitutive activation of c-Abl kinase. Bcr-Abl plays a major role in the development and progression of CML through chronic, accelerated, and blast phases. The interaction between Bcr-Abl and other oncogenic molecules has been extensively documented. Nonetheless, negative regulatory mechanisms of Bcr-Abl are not completely defined. One major inhibitory pathway is mediated via the SH2 domain-containing protein tyrosine phosphatase Shp1. In the present study, we demonstrate that Shp1 levels are markedly decreased in advanced stage CML patients compared with those in chronic phase. This process was independent of DNA methylation. Furthermore, we did not detect mutations in the Shp1 gene in CML cell lines or patient samples. These data suggest that the decrease in Shp1 in advanced stage CML patients is due to post-transcriptional modifications. Our findings suggest that the decrease in Shp1 expression levels plays a role in the progression of CML. Also, the decrease in Shp1 and subsequently its inhibitory effect on Bcr-Abl could provide an explanation for imatinib resistance seen in advanced stage CML patients.
Subject(s)
Leukemia, Myelogenous, Chronic, BCR-ABL Positive/enzymology , Neoplasm Proteins/metabolism , Protein Tyrosine Phosphatase, Non-Receptor Type 6/metabolism , Adult , Aged , DNA Methylation , DNA Mutational Analysis/methods , DNA, Complementary/genetics , DNA, Neoplasm/genetics , Disease Progression , Female , Humans , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Male , Middle Aged , Neoplasm Proteins/genetics , Protein Phosphatase 1 , Protein Tyrosine Phosphatase, Non-Receptor Type 6/genetics , RNA, Messenger/genetics , RNA, Neoplasm/genetics , Reverse Transcriptase Polymerase Chain Reaction/methodsABSTRACT
Groundwater contamination due to releases of petroleum products is a major environmental concern in many urban districts and industrial zones. Over the past years, a few studies were undertaken to address in situ bioremediation processes coupled with contaminant transport in two- or three-dimensional domains. However, they were concentrated on natural attenuation processes for petroleum contaminants or enhanced in situ bioremediation processes in laboratory columns. In this study, an integrated numerical and physical modeling system is developed for simulating an enhanced in situ biodegradation (EISB) process coupled with three-dimensional multiphase multicomponent flow and transport simulation in a multi-dimensional pilot-scale physical model. The designed pilot-scale physical model is effective in tackling natural attenuation and EISB processes for site remediation. The simulation results demonstrate that the developed system is effective in modeling the EISB process, and can thus be used for investigating the effects of various uncertainties.
Subject(s)
Computer Simulation , Environmental Monitoring , Environmental Pollution , Models, Theoretical , Petroleum , Water Pollutants, Chemical , Biodegradation, Environmental , Petroleum/toxicity , Risk Assessment , Water Movements , Water Pollutants, Chemical/toxicityABSTRACT
Oridonin, an extract from the Chinese herb Rabdosia rubescens, is currently one of the most important traditional Chinese herbal medicines. Recently oridonin has been reported to have anti- tumor effects in a large variety of malignant diseases. In this study, we investigated the apoptotic inducing effect of oridonin in leukemia K562 cells and its mechanism. Cell growth inhibition was measured using a microculture tetrazolium assay, apoptosis was measured by flow cytometry and electron microscopy as well as by DNA fragmentation analysis. Telomerase activity was measured by TRAP-enzyme- linked immunosorbent assay, and the expression of Bcl-2 and Bax proteins was detected by western blot analysis. The results showed that oridonin could inhibit the proliferation and induce apoptosis on leukemia K562 cells remarkably. Telomerase activity as well as Bcl-2 expression was down- regulated, while Bax expression was up-regulated concurrently, when apoptosis ocurred. We therefore conclude that oridonin demonstrated anti-proliferative and apoptosis-inducing effects on K562 cells in vitro, and that changes in bcl-2 and bax protein levels as well as telomerase activity may play an important role in its mechanism of action.
Subject(s)
Antineoplastic Agents/pharmacology , Apoptosis , Diterpenes/pharmacology , K562 Cells/drug effects , Cell Proliferation/drug effects , DNA Fragmentation , Diterpenes/chemistry , Diterpenes, Kaurane , Humans , K562 Cells/ultrastructure , Microscopy, Electron , Proto-Oncogene Proteins c-bcl-2/antagonists & inhibitors , Proto-Oncogene Proteins c-bcl-2/biosynthesis , Telomerase/antagonists & inhibitors , Telomerase/metabolism , bcl-2-Associated X ProteinABSTRACT
Oridonin, an extract from the Chinese herb Rabdosia rubescens, is currently one of the most important traditional Chinese herbal medicines. We investigated the anti-proliferative effect of oridonin on the lung cancer cell line SPC-A-1 and its mechanism of action. Growth inhibition was measured using a microculture tetrazolium assay and apoptosis was measured by several standard methods. Western blot analysis measured the expression of bcl-2 and bax proteins. Oridonin (> 28 micromol/l) inhibited the growth of SPC-A-1 cells and induced apoptosis. Marked morphological changes indicative of apoptosis were observed, especially in cells treated with oridonin for 48 - 60 h. Western blot analysis revealed downregulation of bcl-2 and upregulation of bax proteins following treatment with oridonin for 48 h. We conclude that oridonin demonstrated anti-proliferative and apoptosis-inducing effects on SPC-A-1 cells in vitro, and that changes in bcl-2 and bax protein levels may play an important role in its mechanism of action.
Subject(s)
Diterpenes/pharmacology , Isodon/metabolism , Plant Extracts/pharmacology , Apoptosis , Bisbenzimidazole/pharmacology , Blotting, Western , Cell Line, Tumor , Coloring Agents/pharmacology , DNA Fragmentation , Diterpenes, Kaurane , Dose-Response Relationship, Drug , Down-Regulation , Electrophoresis, Agar Gel , Flow Cytometry , Humans , Microscopy, Electron , Proto-Oncogene Proteins c-bcl-2/metabolism , Tetrazolium Salts/pharmacology , Thiazoles/pharmacology , Time Factors , Up-Regulation , bcl-2-Associated X ProteinABSTRACT
The functional enhancement of NMDA receptors after peripheral tissue injury is proposed to contribute to the sensitization of spinothalamic tract (STT) cells and hyperalgesia. Protein phosphorylation is a major mechanism for the regulation of NMDA receptor function. In this study, Western blots, immunofluorescence double labeling, and the retrograde tracing method were used to examine whether phosphorylation of NMDA receptor 1 (NR1) subunits increases in spinal cord tissue and spinal dorsal horn neurons, especially in STT cells, after injection of capsaicin (CAP) into the glabrous skin of one hindpaw of anesthetized rats. Western blots showed that phosphorylated NR1 protein in spinal cord tissue was increased 30 min after CAP injection. Immunofluorescence double-labeling staining showed no significant difference in the number of the NR1-like immunoreactive neurons in laminae I-VII in the lumbosacral segments (L(4)-S(1)) on the ipsilateral and the contralateral sides 30 min after CAP or vehicle injection. However, the numbers of phospho-NR1-like immunoreactive neurons were significantly increased on the ipsilateral side compared with the vehicle injection group. STT cells were labeled by bilateral microinjections of the retrograde tracer fluorogold into the lateral thalamus, including the ventral-posterior lateral nucleus. Immunofluorescence staining was performed at 30, 60, and 120 min after CAP injection or at 30 min after vehicle injection. There was a significant increase in the proportion of STT cells with phosphorylated NR1 subunits compared either with the contralateral side 30 and 60 min after CAP injection or either side of animals after intradermal injection of vehicle. These results provide direct evidence that NMDA receptors in STT cells are phosphorylated after CAP injection.
Subject(s)
Capsaicin/administration & dosage , Posterior Horn Cells/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , Spinothalamic Tracts/metabolism , Stilbamidines , Animals , Blotting, Western , Cell Count/drug effects , Fluorescent Antibody Technique , Fluorescent Dyes/administration & dosage , Hindlimb , Injections, Intradermal , Lumbosacral Region , Male , Microinjections , Phosphorylation/drug effects , Posterior Horn Cells/cytology , Posterior Horn Cells/drug effects , Rats , Rats, Sprague-Dawley , Spinothalamic Tracts/cytology , Spinothalamic Tracts/drug effects , Thalamus/metabolismABSTRACT
OBJECTIVE: To investigate the risk factors of cerebral arteriosclerosis (CAS) in the special population--the old cadre in organizations affiliated directly under Fujian Province. METHODS: The investigation was carried out according to the case control method of epidemiology and conditional logistic regression model was used. RESULTS: Multivariate analysis showed that CAS was closely related with the clinostatic systolic blood pressure (CSBP, OR: 2.13), triglyceride (TG, OR: 2.08), diabetes mellitus (OR: 1.31), glycosylated hemoglobin (OR: 1.16), recall of portrait characteristic (OR: 0.89), Kidney-Deficiency Syndrome (OR: 1.54) and Yin-Deficiency with Yang-Excess Syndrome (OR: 1.59). And there was a quantity-effect relationship between CSBP, TG and CAS. CONCLUSION: CSBP is the most important risk factor of CAS in the special population of the old cadre, and the TCM Syndromes of Kidney-Deficiency and Yin-Deficiency with Yang-Excess are also independent risk factors of CAS.
Subject(s)
Intracranial Arteriosclerosis/epidemiology , Aged , Case-Control Studies , China/epidemiology , Female , Humans , Hypertension/complications , Intracranial Arteriosclerosis/etiology , Logistic Models , Male , Middle Aged , Multivariate Analysis , Risk FactorsABSTRACT
OBJECTIVE: To explore the hemorrheologic changes of gastric cancer in various stages, and the relationship between different phases and Syndrome-types. METHODS: Sixty-three gastric cancer patients and 30 healthy controls matching in sex and age were studied. According to the phases of tumor and the differentiation standards of deficiency and excess syndrome in TCM, the patients were divided into 6 groups: Non-metastasis (NM), lymphnode metastasis (LM), distant metastasis (DM) groups, and Deficiency (D), Excess (E), mixed deficiency and excess (DE) groups. The hemorrheology criteria including whole blood viscosity (BV), plasma viscosity (PV), hematocrit (HCT), fibrinogen (Fib), platelet count (PC), platelet aggregation rate (PAR) were measured. RESULTS: The value of BV, PV, Fib, PC and PAR in gastric cancer groups were higher significantly (P < 0.05, P < 0.01) than those in the healthy control group, but BV, PV in the LM and DM groups were higher than those in the healthy control group significantly (P < 0.05), while difference between NM group and the healthy control group was insignificant (P > 0.05). Hypercoagulability state presented in all the three Syndrome Type groups of gastric cancer patients, but the difference in some criteria between D and E group were significant (P < 0.05, P < 0.01); and DE groups was greatly higher than D and E groups in high-shear BV, Fib and PC (P < 0.05, P < 0.01). CONCLUSION: The value of BV, PV Fib, PC and PAR could be regarded as good referential parameters in reflecting the condition of evil excess.
Subject(s)
Hemorheology , Medicine, Chinese Traditional , Stomach Neoplasms/blood , Adult , Aged , Blood Viscosity , Diagnosis, Differential , Female , Humans , Lymphatic Metastasis , Male , Middle Aged , Stomach Neoplasms/classification , Stomach Neoplasms/pathologyABSTRACT
The data have been sorted and calculated by statistics for personages' life-span according to surname and Yin-Yang type and disease according to the cause of pattern over 793 personage from the biography of emperor families' and official in feudal times and subjects of the feudal ruler in History Book of Song Dynasty. (1) For there are some genetic diseases causing their earlier death in surname Zhao's, the average value of life-span is shorter than the other surname of Wang, Li, Zhang, Liu and Chen's. Because the average value among those five surnames are not different each other, the character of the distribution of every one's tally with neuter alleles. (2) The average value in a population on a type of mild Yin and Yang is higher than the type of Yang only, P < 0.05. (3) Disease and bad environment are the limiting factors for life. Besides, to rise the resistance ability is an important path way for increasing our life-span. The attribute of a genetic system in Yin or Yang is an objective existence. Influence on life by genetics may vary with various disease and environment, but different disease is controlled genetically. A bad environment may affect life, but neuter environment would be affected the life through attribute of a genetic system in Yin or Yang type indirectly.
Subject(s)
Environment , Genetics , Life Expectancy , HumansABSTRACT
OBJECTIVE: To explore the antiendotoxin effect of extracts from Artemisia annua (AA) and qinghaosu (QHS). METHOD: LPO and SOD in chondriosome, ACP in lysosomes, tumor nicrosis factor-alpha(TNF-alpha) and endotoxin in plasma, and P450 concentration in hepatic microsome of rats were determined. Mortality of endotoxemic mice and histomorphology were observed. RESULT: LPO, ACP, endotoxin, TNF-alpha and P450 content were decreased with AA and QHS. SOD activity was increased with AA and QHS. At the same time, mortality was decreased. Histomorphology of lysosomes and chondriosome of rats were protected from endotoxin. CONCLUSION: AA and QHS possess an antiendotoxin effect.
Subject(s)
Artemisia/chemistry , Artemisinins/pharmacology , Drugs, Chinese Herbal/pharmacology , Endotoxins/antagonists & inhibitors , Microsomes, Liver/enzymology , Sesquiterpenes/pharmacology , Animals , Artemisinins/isolation & purification , Cytochrome P-450 Enzyme System/metabolism , Drugs, Chinese Herbal/isolation & purification , Endotoxins/blood , Female , Male , Mice , Random Allocation , Rats , Rats, Wistar , Sesquiterpenes/isolation & purification , Superoxide Dismutase/metabolismABSTRACT
OBJECTIVE: TCM and western geriatric medical principles were used to study the assessment of aging in mankind. METHODS: The authors studied and examined 387 healthy subjects ranging from 45 to 69 years of age. Its indices included 24 TCM senility syndromes, 5 western medical neurophysiological indices. Thereafter, regression analysis was used to deduce a TCM-WM aging formula. RESULTS: Data from all clinical subjects were processed using integrated TCM-WM, physiological age formula to determine the physiological ages (Y) and their corresponding calendar ages (y). The mean values of the age differential of zero, and a standard deviation of 2.29 years were calculated. From statistical view point, a 95 percentage is an acceptable normal value range. Also, as the objective of the aging assessment only used the higher end of the range. I.E., it is considered there is excessive aging when physiological age is higher than calendar age by 3.37 years. In the process of conducting regression analysis, the authors also discovered that LPO can increase TCM senility syndrome score, whereas CuZnSOD decrease it. CONCLUSIONS: The above clinical study showed that the regression analysis and age-related TCM indices can comprehensively reflect the natural process of aging in mankind. It also demonstrated the highly predictive nature of TCM senility syndrome score.
Subject(s)
Aging , Medicine, Chinese Traditional , Superoxide Dismutase/blood , Yang Deficiency , Aged , Aging/blood , Aging/immunology , Female , Humans , Lipid Peroxides/blood , Male , Mass Screening , Middle Aged , Reference Standards , Regression AnalysisABSTRACT
OBJECTIVE: To elevate the efficacy of dialysis in uremia patients treated with maintaining hemodialysis. METHODS: Thirty patients of terminal stage uremia were treated with Tongmai oral liquid and rhubarb capsule combined with hemodialysis were observed and compared with a control group of 30 patients treated with hemodialysis alone. The therapeutic course of both groups was 1 month and the observation lasted for 3 months consecutively. RESULTS: The mean time urea nitrogen concentration, protein catabdic rate and the GS index (KT/V value) of the treated group were all better than those of the control group (P < 0.05). CONCLUSION: Uremia patients treated with Tongmai oral liquid and rhubarb capsule combined with hemodialysis were better in full utilization of hemodialysis and life quality of patients in comparison with patients treated with hemodialysis alone.
Subject(s)
Drugs, Chinese Herbal/therapeutic use , Renal Dialysis , Uremia/therapy , Adult , Aged , Combined Modality Therapy , Female , Humans , Male , Middle Aged , Phytotherapy , Plants, Medicinal , Rheum/therapeutic useABSTRACT
The design, synthesis, and evaluation of a novel series of receptors for protein surface recognition are described. The design of these agents is based around the attachment of four constrained peptide loops onto a central calix[4]arene scaffold. This arrangement mimics the role of the hypervariable loops in antibody combining regions and defines a large surface area for binding to a complementary region of the exterior of a target protein. Using affinity and gel filtration chromatographies we show that one particular receptor binds strongly to the surface of cytochrome c. The site of binding is presumably close to the heme edge region, which contains several charged lysine residues. This is supported by the observation that the receptor inhibits the reduction of Fe(III) cytochrome c to its Fe(II) form. We also show that binding is strongly dependent on the nature of the substituents on the lower rim of the calixarene. The nmr and computational studies suggest that this effect may be due to conformational differences among the differently substituted receptors.
Subject(s)
Cytochrome c Group/metabolism , Protein Binding , Receptors, Cell Surface/chemistry , Animals , Antibodies/chemistry , Ascorbic Acid/metabolism , Binding Sites , Calixarenes , Chromatography, Gel , Horses , Kinetics , Macromolecular Substances , Magnetic Resonance Spectroscopy , Mass Spectrometry , Models, Molecular , Molecular Conformation , Molecular Structure , Oxidation-Reduction , Peptides, Cyclic/chemical synthesis , Protein EngineeringABSTRACT
Elevated concentration of plasma total homocysteine (tHcy) is a common risk factor for arterial occlusive diseases. Folic acid (FA) supplementation usually lowers tHcy levels, but initial tHcy and vitamin levels, multivitamin use, and polymorphisms in the gene for 5, 10-methylenetetrahydrofolate reductase (MTHFR) may contribute to variability in reduction. We tested the effects of a 3-week daily intake of 1 or 2 mg of FA supplements on tHcy levels in patients with and without coronary heart disease (CHD) who were analyzed for the C677T MTHFR mutation. Prior multivitamin intake and baseline vitamin and tHcy levels were also compared with responsiveness to folate supplementation. Both dosages of FA lowered tHcy levels similarly, regardless of sex, age, CHD status, body mass index, smoking, or plasma creatinine concentration. In non-multivitamin users, FA supplements reduced tHcy by 7% in C/C homozygotes and by 13% or 21% in subjects with one or two copies of the T677 allele, respectively; the corresponding reductions were smaller in users of multivitamins. Moreover, T/T homozygotes had elevated tHcy and increased susceptibility to high levels of tHcy at marginally low plasma folate levels, as well as enhanced response to the tHcy-lowering effects of FA. Although other factors are probably involved in the responsiveness of tHcy levels to FA supplementation, about one third of heterogeneity in responsiveness was attributable to baseline tHcy and folate levels and to multivitamin use.