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1.
Transpl Immunol ; 75: 101714, 2022 12.
Article in English | MEDLINE | ID: mdl-36108808

ABSTRACT

Acute cellular rejection (ACR) occurs in 10% of renal allograft recipients and is characterized by leukocyte infiltration as observed in needle biopsies. ACR onset is subject to several risk factors, including delayed graft function (DGF). As the impact of DGF on the etiology of ACR remains unclear, this study analyzed the association between presence of leukocyte subsets and ACR onset, in DCD kidney biopsies with extensive DGF following transplantation. Immunohistochemical analysis of protocol biopsies taken 10 days after kidney transplantation revealed that patients with high levels of renal CD163+ macrophages have a decreased risk (OR = 0.021, P = 0.008) for ACR in the first 6 months after transplantation. In pre-transplant biopsies of a comparable DCD cohort, with >80% DGF, presence of donor CD163+ macrophages showed no effect on ACR risk. Therefore, leukocyte infiltrate present during the inflammatory response at the time of DGF may contain anti-inflammatory macrophages that exert a protective effect against ACR development.


Subject(s)
Kidney Transplantation , Humans , Kidney Transplantation/adverse effects , Delayed Graft Function , Graft Survival , Graft Rejection/etiology , Tissue Donors , Kidney , Risk Factors , Macrophages , Retrospective Studies
2.
Am J Transplant ; 19(1): 110-122, 2019 01.
Article in English | MEDLINE | ID: mdl-29786954

ABSTRACT

Extending kidney donor criteria, including donation after circulatory death (DCD), has resulted in increased rates of delayed graft function (DGF) and primary nonfunction. Here, we used Nuclear Magnetic Resonance (NMR) spectroscopy to analyze the urinary metabolome of DCD transplant recipients at multiple time points (days 10, 42, 180, and 360 after transplantation). The aim was to identify markers that predict prolonged duration of functional DGF (fDGF). Forty-seven metabolites were quantified and their levels were evaluated in relation to fDGF. Samples obtained at day 10 had a different profile than samples obtained at the other time points. Furthermore, at day 10 there was a statistically significant increase in eight metabolites and a decrease in six metabolites in the group with fDGF (N = 53) vis-à-vis the group without fDGF (N = 22). In those with prolonged fDGF (≥21 days) (N = 17) urine lactate was significantly higher and pyroglutamate lower than in those with limited fDGF (<21 days) (N = 36). In order to further distinguish prolonged fDGF from limited fDGF, the ratios of all metabolites were analyzed. In a logistic regression analysis, the sum of branched-chain amino acids (BCAAs) over pyroglutamate and lactate over fumarate, predicted prolonged fDGF with an AUC of 0.85. In conclusion, kidney transplant recipients with fDGF can be identified based on their altered urinary metabolome. Furthermore, two ratios of urinary metabolites, lactate/fumarate and BCAAs/pyroglutamate, adequately predict prolonged duration of fDGF.


Subject(s)
Delayed Graft Function/urine , Kidney Failure, Chronic/surgery , Kidney Transplantation , Adult , Aged , Amino Acids, Branched-Chain/urine , Area Under Curve , Biomarkers/urine , Female , Fumarates/urine , Glomerular Filtration Rate , Graft Survival , Humans , Kidney Failure, Chronic/urine , Lactic Acid/urine , Magnetic Resonance Spectroscopy , Male , Middle Aged , Pyrrolidonecarboxylic Acid/metabolism , Pyrrolidonecarboxylic Acid/urine , ROC Curve , Time Factors
3.
J Neuroendocrinol ; 29(7)2017 07.
Article in English | MEDLINE | ID: mdl-28514514

ABSTRACT

Djungarian hamsters are able to reduce their body weight by more than 30% in anticipation of the winter season. This particular adaptation to extreme environmental conditions is primarily driven by a natural reduction in day length and conserved under laboratory conditions. We used this animal model to investigate hypothalamic gene expression linked to body weight regulation behind this physiological phenomenon. After an initial collective short photoperiod (SP) adaptation for 14 weeks from a preceding long photoperiod (LP), hamsters were re-exposed to LP for either 6 or 14 weeks, followed by a second re-exposure to SP for 8 weeks. Our data showed that re-exposure to LP led to an increase in body weight. In the hypothalamus Dio2, Vimentin, Crbp1 and Grp50 expression increased, whereas expression of Dio3, Mct8 and Srif decreased. The changes in body weight and gene expression were reversible in most hamsters after a further re-exposure to SP following 6 or 14 weeks in LP. Interestingly, after 14 weeks in LP, body weight loss was pronounced in six hamsters re-exposed to SP, but five hamsters did not respond. In nonresponding hamsters, a different gene expression pattern was manifested, with the exception of Dio2, which was reduced not only in SP re-exposed hamsters, but also in hamsters maintained in LP. Taken together, these data suggest that body weight regulation appears to be tightly linked to a co-ordinated regulation of several genes in the hypothalamus, including those involved in thyroid hormone metabolism.


Subject(s)
Body Weight/physiology , Gene Expression Regulation , Hypothalamus/metabolism , Phodopus/physiology , Photoperiod , Seasons , Animals , Cricetinae , Female , Iodide Peroxidase/genetics , Iodide Peroxidase/metabolism , Male , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Receptors, G-Protein-Coupled/genetics , Receptors, G-Protein-Coupled/metabolism , Vimentin/genetics , Vimentin/metabolism , Iodothyronine Deiodinase Type II
4.
J Immunol Res ; 2015: 391797, 2015.
Article in English | MEDLINE | ID: mdl-26258149

ABSTRACT

Despite excellent short-term graft survival after renal transplantation, the long-term graft outcome remains compromised. It has become evident that a combination of sustained alloreactivity and calcineurin-inhibitor- (CNI-) related nephrotoxicity results in fibrosis and consequently dysfunction of the graft. New immunosuppressive regimens that can minimize or eliminate side effects, while maintaining efficacy, are required to improve long-term graft survival. In this perspective mesenchymal stromal cells (MSCs) are an interesting candidate, since MSCs have immunosuppressive and regenerative properties. The first clinical trials with MSCs in renal transplantation showed safety and feasibility and displayed promising results. Recently, the first phase II studies have been started. One of the most difficult and challenging aspects in those early phase trials is to define accurate endpoints that can measure safety and efficacy of MSC treatment. Since both graft losses and acute rejection rates declined, alternative surrogate markers such as renal function, histological findings, and immunological markers are used to measure efficacy and to provide mechanistic insight. In this review, we will discuss the current status of MSCs in renal transplantation with a focus on the endpoints used in the different experimental and clinical studies.


Subject(s)
Cell- and Tissue-Based Therapy , Kidney Transplantation , Mesenchymal Stem Cell Transplantation , Mesenchymal Stem Cells/cytology , Animals , Clinical Trials as Topic , Graft Rejection/prevention & control , Graft Survival , Humans , Immunomodulation , Mesenchymal Stem Cell Transplantation/adverse effects , Mesenchymal Stem Cells/immunology , Transplantation, Homologous , Treatment Outcome
5.
Eur J Nucl Med Mol Imaging ; 29(2): 216-20, 2002 Feb.
Article in English | MEDLINE | ID: mdl-11926383

ABSTRACT

Dynamic imaging of the inflow of technetium-99m hexamethylpropylene amine oxime (HMPAO) to the brain has been proved to allow estimation of the hemispherical cerebral blood flow (CBF) using the Patlak plot. In this study, we compared the hemispherical CBF (in ml/min/100 g) of different patient groups. A total of 25 patients (comprising 13 with migraine and 12 scheduled for endarterectomy owing to angiographically confirmed severe stenosis of the internal carotid artery on at least one side) underwent baseline and acetazolamide 99mTc-HMPAO brain perfusion studies. In addition, acetazolamide 99mTc-HMPAO studies were performed in 12 healthy subjects (no baseline study was performed for ethical reasons.) Dynamic studies were acquired by means of a dual-detector gamma camera with a large field of view (HELIX, Elscint). Special difference images were created to make definition of the aortic arch and hemispherical brain regions easier and more reproducible. A semi-automatic method was developed to determine the transit time from the aorta to the brain, making the generation of the Patlak plot even more robust. The baseline CBF values did not significantly depend on the disease (P>0.1), whereas the CBF values obtained after acetazolamide provocation did do so (ANOVA, P<0.001). Patients suffering from migraine showed a significant increase in global CBF values after acetazolamide provocation (paired t test, P<0.05), but we could not find any effect of the provocation in patients awaiting carotid endarterectomy, indicating a lack of cerebrovascular reserve capacity. Comparison of the results of the acetazolamide study in patients and the control group revealed the CBF values to be significantly lower in patients with carotid stenosis (two-sample t-test, P<0.001), but not in those with migraine (P>0.1). In summary, using quantitative analysis of 99mTc-HMPAO brain studies we could objectively compare the CBF of patients suffering from different diseases. Especially the CBF values obtained after acetazolamide provocation permitted effective differentiation of disease states. The quantitative results may be of assistance in therapy planning, e.g. in selection of the correct operative technique.


Subject(s)
Carotid Stenosis/diagnostic imaging , Radiopharmaceuticals , Technetium Tc 99m Exametazime , Acetazolamide , Adult , Aged , Carotid Stenosis/physiopathology , Case-Control Studies , Cerebrovascular Circulation/drug effects , Female , Humans , Male , Middle Aged , Migraine Disorders/diagnostic imaging , Regional Blood Flow , Tomography, Emission-Computed, Single-Photon
6.
Headache ; 41(1): 84-7, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11168608

ABSTRACT

As a nitric oxide donor, nitroglycerin can trigger migraine in migraineurs. The headache is not characteristically accompanied by an aura. A patient with no personal or family history of migraine reported the development of a typical visual aura and a throbbing headache while using nitroglycerin for angina pectoris. The possible mechanisms are discussed.


Subject(s)
Migraine with Aura/chemically induced , Nitroglycerin/adverse effects , Vasodilator Agents/adverse effects , Administration, Sublingual , Angina Pectoris/drug therapy , Animals , Humans , Male , Middle Aged , Migraine with Aura/physiopathology , Nitroglycerin/therapeutic use , Vasodilator Agents/therapeutic use
7.
Cell Commun Adhes ; 8(3): 113-23, 2001.
Article in English | MEDLINE | ID: mdl-11936186

ABSTRACT

The alpha1 beta1 integrin, an inserted (1) domain containing collagen receptor, is expressed in the cell surface membrane of normal and malignant cells, and may play a role in their migration through tissues or in metastatic spread. Here we report that a functional anti-human alpha1beta1 integrin monoclonal antibody (mAb) (1B3.1) directly and specifically binds plastic bound recombinant human alpha1 I-domain protein containing the collagen binding site. Detection was diminished by acidification of the I-domain protein but was enhanced by increasing concentrations of Mg2+ cation. Furthermore, we detected binding of the mAb to proteins from the ocular fluids of 6 patients, with the highest concentration, corresponding to 22.1 ng/ml of I-domain, found in a sample from the eye of a patient with metastatic lung adenocarcinoma. Interestingly, we found that both SKNSH neuroblastoma cells and virally transformed human T cells adhered specifically to plastic wells coated with either immobilized collagen IV or alpha1 I-domain. MAb I B3.1 inhibited adhesion to collagen IV but not to immobilized I-domain. These results suggest a novel function for cell free alpha1 I-domain as a substrate for cellular adhesion, which may have relevance in tumor spread in vivo.


Subject(s)
Antibodies, Monoclonal/immunology , Aqueous Humor/chemistry , Cell Adhesion Molecules/immunology , Enzyme-Linked Immunosorbent Assay/methods , Integrin alpha1/immunology , Adenocarcinoma/diagnosis , Adenocarcinoma/secondary , Cataract/diagnosis , Cations/chemistry , Cell-Free System , Eye Neoplasms/secondary , Humans , Integrin alpha1/chemistry , Integrin alpha1/physiology , Integrin alpha1beta1/immunology , Lung Neoplasms/diagnosis , Lung Neoplasms/pathology , Protein Structure, Tertiary
8.
Headache ; 40(2): 164-9, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10759917

ABSTRACT

OBJECTIVE: A population-based epidemiological survey of migraine without aura and migraine with aura completed by mailed questionnaire in Hungary. The diagnosis and classification of migraine was according to the criteria of the International Headache Society. METHODS: The validity of the self-administered headache questionnaire was evaluated by a neurologist using clinical interviews. The study population was a random sample of 2000 men and women aged between 15 and 80 years. The questionnaire was completed by 813 of 1910 people (392 men and 421 women), providing a 42.6% participation rate. RESULTS: Sixty-seven percent of these people experienced some kind of headache during their lives. The 1-year prevalence of migraine without aura was 7.6% (the female/male ratio was 3:1), while the 1-year prevalence of migraine with aura was 2% (female/male ratio was 2:1). Most migraineurs experienced headache attacks 1 to 4 times monthly, which lasted 24 hours. The most characteristic accompanying signs were nausea and phonophobia. Stress, sleep deprivation, hot weather, and fasting were the most common precipitating factors of a migraine attack. In the migraine with aura group, the most common aura was a visual disturbance. Only 43% of migraineurs had ever consulted a physician for headache, and only 15% of patients had missed work or school because of a migraine attack in the previous year. Most of the patients suffering from migraine without aura were between 20 and 40 years old, while migraineurs with aura were over 40 years old. According to this investigation, the prevalence of migraine was not lower than in Western countries.


Subject(s)
Migraine Disorders/epidemiology , Migraine with Aura/epidemiology , Adolescent , Adult , Aged , Aged, 80 and over , Cohort Studies , Female , Humans , Hungary/epidemiology , Male , Middle Aged , Migraine Disorders/etiology , Prevalence , Random Allocation , Socioeconomic Factors , Urban Population/statistics & numerical data
11.
Headache ; 34(8): 476-8, 1994 Sep.
Article in English | MEDLINE | ID: mdl-7960733

ABSTRACT

Current treatment of migraine either abortive or prophylactic is often unsatisfactory. Prophylactic treatment of severe migraine may reduce attack frequency, and current therapy centers on beta-blockers, serotonin (5-HT) reuptake blockers and 5-HT2 receptor antagonists. The author compared the efficacy and safety of amitriptyline and fluvoxamine among migraine patients (24F, 8M vs. 23F, 9M) in a double blind study. The efficacy of amitriptyline has already been established by earlier clinical studies. The other investigated drug, fluvoxamine, has a more selective 5-HT reuptake blocking property than amitriptyline. In this study, amitriptyline significantly reduced the number of headache attacks, but it caused severe drowsiness in many migraineurs. The fluvoxamine also favorably influenced on the number of headache attacks and caused only slight side effects. These findings suggest, that fluvoxamine may be an alternative drug in migraine prophylaxis, however, further studies should be performed with more subjects.


Subject(s)
Amitriptyline/therapeutic use , Fluvoxamine/therapeutic use , Migraine Disorders/prevention & control , Adult , Female , Humans , Male , Middle Aged
12.
Cephalalgia ; 12(5): 289-92, 1992 Oct.
Article in English | MEDLINE | ID: mdl-1423559

ABSTRACT

The blink reflex is an objective and useful method to study the trigeminal system. It was recorded in 43 migraine patients and the findings compared with those of 31 healthy controls. The latencies of the R1 component were in the normal range in both groups. The R2 latencies ranged between 30 and 32 ms in the control group. In contrast, more than half of the patients with migraine had R2 latencies between 32 and 35 ms in the migraine group. Some migraine patients had latencies above 35 ms. The R2 latency was statistically significantly different between controls and migraineurs (p < 0.0001). Our findings indicate that trigeminal afferents and/or polysynaptic pathway in brainstem may be altered in migraine.


Subject(s)
Blinking , Migraine Disorders/physiopathology , Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , Reaction Time , Reference Values
13.
Biochemistry ; 31(5): 1331-9, 1992 Feb 11.
Article in English | MEDLINE | ID: mdl-1310609

ABSTRACT

This work broadens the scope and improves the time resolution of spin-probe oximetry, a technique in which small nitroxide spin probes detect oxygen consumption via change in their relaxation properties [Froncisz, W., Lai, C.-S., & Hyde, J. S. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 411-415]. For rapid oxygen kinetic studies we combined the methodology of spin-probe oximetry with a recently developed loop-gap resonator, stopped-flow EPR system [Hubbell, W. L., Froncisz, W., & Hyde, J. S. (1987) Rev. Sci. Instrum. 58, 1879-1886]. The technique used microliter volumes of reactant solutions. Enzymatic consumption of oxygen by cytochrome c oxidase in the presence of ferrocytochrome c substrate was followed continuously in time under limited-turnover conditions, where the concentration of oxygen consumed often was comparable to or less than the amount of enzyme present. In detecting less than micromolar oxygen concentration changes, we have achieved a time resolution of the order 30 ms when flow is stopped. Oxygen consumption was followed under two different limited-turnover conditions: In the first, the amount of oxygen consumed was limited by available ferrocytochrome c, and the time course of oxygen consumption and its pH dependence were compared with the optically detected ferrocytochrome c consumption. In the second, the oxygen consumed was ultimately limited by the availability of oxygen itself while ferrocytochrome c was regenerated and remained in excess.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Electron Spin Resonance Spectroscopy , Electron Transport Complex IV/chemistry , Oxygen Consumption , Animals , Cattle , Cyclic N-Oxides , Cytochrome c Group/chemistry , Electron Spin Resonance Spectroscopy/methods , Kinetics , Oximetry , Spin Labels
14.
Cephalalgia ; 11(6): 277-9, 1991 Dec.
Article in English | MEDLINE | ID: mdl-1790573

ABSTRACT

Brainstem auditory evoked potentials were recorded in 34 migraine patients (21 F and 13 M, mean age 37.4 +/- 8.1 years) after Rausedyl (2.5 mg reserpine) provocation. Intramuscular injection of reserpine induces a typical headache in migrainous controls. The findings were compared with those of 40 healthy controls (25 F and 15 M with a mean age of 40 +/- 8.9 years). We evaluated I, III, V and I-III, III-V, I-V peak and interpeak latencies. We did not find significant differences after provocation in the control group. In the migraine group, V waves were delayed significantly and consecutively I-V interpeak latencies were increased. Our results indicate an impairment of the rostral brainstem function after reserpine provocation in migraine patients.


Subject(s)
Evoked Potentials, Auditory, Brain Stem/physiology , Migraine Disorders/physiopathology , Reserpine , Adult , Electromyography , Evoked Potentials, Auditory, Brain Stem/drug effects , Female , Humans , Male , Middle Aged , Migraine Disorders/chemically induced , Reaction Time
15.
Cancer ; 66(8): 1748-54, 1990 Oct 15.
Article in English | MEDLINE | ID: mdl-2208030

ABSTRACT

The purpose of this study was to determine whether the presence of more than 5% blasts in a differential count of cytocentrifuged cerebrospinal fluid (CSF) with less than 6 leukocytes/microliter was predictive of central nervous system (CNS) relapse in children with acute lymphoblastic leukemia (ALL). A double concentrate method of cytocentrifuge preparation was used to analyze 4543 consecutive CSF specimens from 349 children with ALL between January 1, 1982, and September 30, 1988. One hundred nine CSF specimens from 58 evaluable children had less than 6 leukocytes/microliter and more than 5% blasts on cytocentrifuge differential count (low-cell-count specimen with blasts [LCB]). During the study period, 25 of 332 evaluable children (7.5%) had CNS leukemic recurrence. In 22 of 25 (88%), the CNS relapse was preceded by at least one abnormal low-cell-count CSF specimen. One of 34 patients with a single LCB at diagnosis (3%) had subsequent CNS relapse compared with five of eight patients (62.5%) with a single LCB during remission (P = 0.0002). Of 16 children with two or more LCB during remission, nine (56%) had CNS relapse defined by standard criteria, whereas six additional patients in this group were declared to be in CNS relapse on the basis of their repetitive LCB. Whether diagnosing CNS recurrence earlier in its course based on a modification of the definition of CNS leukemia will change the frequency of subsequent adverse events or make possible decreased intensity of CNS retreatment remains to be determined.


Subject(s)
Cerebrospinal Fluid/cytology , Leukocytes/pathology , Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology , Adolescent , Child , Child, Preschool , Female , Humans , Infant , Leukocyte Count , Male , Precursor Cell Lymphoblastic Leukemia-Lymphoma/diagnosis , Prognosis , Recurrence
16.
J Behav Med ; 13(5): 467-80, 1990 Oct.
Article in English | MEDLINE | ID: mdl-2273524

ABSTRACT

The purpose of this study was to examine the cephalic blood flow patterns of subjects with frequent headaches during a headache induction procedure. Thirty-six subjects with muscle-contraction, migraine, or mixed headache symptoms were exposed to a 1-hr stressor designed to induce a headache while multiple cephalic blood volume pulse amplitude (BVPA) was measured. Thirty subjects reported a headache during the procedure, and the procedure was associated with significant changes in several cephalic BVPA measures. Between-group differences were found for several cephalic BVPA sites and there were significant correlations between induced headache activity and cephalic BVPA measures for most subjects. The results support causal roles for psychosocial stressors and cephalic blood flow in muscle-contraction and migraine headache.


Subject(s)
Arousal/physiology , Head/blood supply , Headache/physiopathology , Migraine Disorders/physiopathology , Muscle Contraction/physiology , Vasomotor System/physiopathology , Adult , Blood Flow Velocity/physiology , Female , Humans , Male , Vasoconstriction/physiology
17.
Neoplasma ; 37(2): 173-8, 1990.
Article in English | MEDLINE | ID: mdl-2188164

ABSTRACT

In the screening examinations of 150 ore miners the positive humoral immune response against lung tumor antigen was measured in 30 serum samples. Repeated testing of positive sera (after 1-3 years) was possible only in 15 cases. Among them, the reaction of 12 serum samples was again positive, and 2 persons died of lung cancer. The results obtained in these follow-up investigations are discussed.


Subject(s)
Immunologic Techniques , Leukocyte Adherence Inhibition Test , Lung Neoplasms/diagnosis , Adult , Antigens, Neoplasm/immunology , Humans , Lung Neoplasms/immunology , Male , Middle Aged , Mining , Occupational Diseases/diagnosis , Risk Factors
18.
Biochemistry ; 28(10): 4450-5, 1989 May 16.
Article in English | MEDLINE | ID: mdl-2548577

ABSTRACT

Elemental analyses, Mössbauer, and EPR data are reported to show that endonuclease III of Escherichia coli is an iron-sulfur protein. Mössbauer spectra of protein freshly prepared from E. coli grown on 57Fe-enriched medium demonstrate that the native enzyme contains a single 4Fe-4S cluster in the 2+ oxidation state, with a net spin of zero. Upon treatment with ferricyanide, a fraction (less than 25%) of the clusters is oxidized into a state which yields an EPR spectrum near g = 2.01 typical of a 3Fe-4S cluster. The magnetic field dependence of the linear electric field effect verifies this assignment. Electron spin echo modulation on the g = 2.01 form of the protein in deuterated solvent indicates the presence of exchangeable protons in the vicinity of the 3Fe-4S cluster. The data obtained show that the [4Fe-4S]2+ cluster of the native enzyme is resistant to either oxidation or reduction, although photoreduction elicited a g = 1.94 type EPR signal characteristic of a [4Fe-4S]1+ cluster. These studies show that endonuclease III is unique in being both a DNA repair enzyme and an iron-sulfur protein. The function of the 4Fe-4S cluster remains to be established.


Subject(s)
Endodeoxyribonucleases/metabolism , Escherichia coli Proteins , Iron-Sulfur Proteins/metabolism , Metalloproteins/metabolism , Deoxyribonuclease (Pyrimidine Dimer) , Electron Spin Resonance Spectroscopy , Escherichia coli/metabolism , Spectroscopy, Mossbauer
19.
Biochemistry ; 28(10): 4444-9, 1989 May 16.
Article in English | MEDLINE | ID: mdl-2669955

ABSTRACT

The gene which codes for endonuclease III of Escherichia coli has been sequenced. The nth gene was previously subcloned and defined as the gene which led to overproduction of endonuclease III when present on a multicopy plasmid and which created a deficiency in endonuclease III activity when mutated. The nth gene was sequenced and translated into a predicted polypeptide. The molecular weight (23,546), the amino-terminal amino acid sequence, and the amino acid composition of the polypeptide predicted from the nucleotide sequence are excellent agreement with those same properties determined for the purified protein. Thus, the nth gene is the structural gene for endonuclease III. Inspection of the nucleotide sequence reveals that there is an open reading frame immediately upstream of the nth gene, suggesting that it might be part of an operon. There is a region of dyad symmetry which could form a hairpin stem and loop structure if transcribed into RNA characteristic of a rho-dependent terminator downstream from the nth gene. The nth gene of Escherichia coli has been cloned onto a lambda PL expression vector which yields approximately 300-fold overproduction of endonuclease III. We have purified the enzyme to apparent homogeneity using two chromatographic steps. Our purification scheme allowed the preparation of 117 mg of protein from 190 g of E. coli with a 70% yield. The purified protein has both AP endonuclease activity and DNA N-glycosylase activity. The protein has a Stokes radius of 2.25 nm, a sedimentation coefficient of 2.65 S, a molecular weight of 26,300 in the native state and 27,300 in the denatured state, and a frictional ratio of 1.13.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Endodeoxyribonucleases/genetics , Escherichia coli Proteins , Escherichia coli/genetics , Genes, Bacterial , Amino Acid Sequence , Base Sequence , Cloning, Molecular , DNA, Bacterial/genetics , Deoxyribonuclease (Pyrimidine Dimer) , Endodeoxyribonucleases/isolation & purification , Escherichia coli/enzymology , Genes , Genetic Vectors , Molecular Sequence Data
20.
J Biol Chem ; 263(8): 3588-91, 1988 Mar 15.
Article in English | MEDLINE | ID: mdl-2831193

ABSTRACT

We measured an electronic change at cysteine ligand(s) of the CuA2+ center brought on by reduction of other metal centers within cytochrome c oxidase, notably cytochrome a. This change specifically manifested itself as a modification in magnetic hyperfine coupling to the beta-protons of the beta-carbons adjacent to the cysteine sulfur in the CuA2+ coordination sphere. The electron nuclear double resonance ENDOR signals of these beta-protons had previously been assigned through study of selectively deuterated yeast oxidase. In the present study the ENDOR signals of the CuA2+ center were compared from the following forms of oxidase: resting (a3+.CuA2+.a3+3.CuB2+); mixed valence, 2-electron-reduced CO-ligated oxidase (a3+.CuA2+.a2+3CO.CuB+), and a more completely reduced mixed-valence CO-ligated oxidase. In agreement with previous studies on 3-electron-reduced oxidase, the latter more completely reduced oxidase showed cytochrome a preferentially reduced with respect to CuA, implying that the majority of paramagnetic CuA2+ centers had reduced cytochrome a partners. The ENDOR-resolved splitting of the beta-proton hyperfine features substantially decreased in going from the first two more oxidized forms to the more fully reduced latter form. Thus, the electronic structure of the CuA2+ center specifically monitored by hyperfine couplings to cysteine protons changed in response to a reductive event elsewhere in the protein. This structural change may correlate with the anticooperative redox interaction recently reported between cytochrome a and CuA.


Subject(s)
Copper/metabolism , Electron Transport Complex IV/metabolism , Animals , Binding Sites , Carbon Dioxide/metabolism , Cattle , Cysteine , Electron Spin Resonance Spectroscopy/methods , Magnetic Resonance Spectroscopy/methods , Myocardium/enzymology , Protein Binding , Protein Conformation
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