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1.
J Affect Disord ; 242: 68-79, 2019 01 01.
Article in English | MEDLINE | ID: mdl-30172227

ABSTRACT

BACKGROUND: Non-response to repetitive transcranial magnetic stimulation (rTMS) treatment for depression is costly for both patients and clinics. Simple and cheap methods to predict response would reduce this burden. Resting EEG measures differentiate responders from non-responders, so may have utility for response prediction. METHODS: Fifty patients with treatment resistant depression and 21 controls had resting electroencephalography (EEG) recorded at baseline (BL). Patients underwent 5-8 weeks of rTMS treatment, with EEG recordings repeated at week 1 (W1). Forty-two participants had valid BL and W1 EEG data, and 12 were responders. Responders and non-responders were compared at BL and W1 in measures of theta (4-8 Hz) and alpha (8-13 Hz) power and connectivity, frontal theta cordance and alpha peak frequency. Control group comparisons were made for measures that differed between responders and non-responders. A machine learning algorithm assessed the potential to differentiate responders from non-responders using EEG measures in combination with change in depression scores from BL to W1. RESULTS: Responders showed elevated theta connectivity across BL and W1. No other EEG measures differed between groups. Responders could be distinguished from non-responders with a mean sensitivity of 0.84 (p = 0.001) and specificity of 0.89 (p = 0.002) using cross-validated machine learning classification on the combination of all EEG and mood measures. LIMITATIONS: The low response rate limited our sample size to only 12 responders. CONCLUSION: Resting theta connectivity at BL and W1 differ between responders and non-responders, and show potential for predicting response to rTMS treatment for depression.


Subject(s)
Depressive Disorder, Major/therapy , Depressive Disorder, Treatment-Resistant/diagnosis , Transcranial Magnetic Stimulation/methods , Adult , Aged , Algorithms , Depressive Disorder, Major/physiopathology , Electroencephalography/methods , Female , Humans , Male , Middle Aged , Sensitivity and Specificity , Young Adult
2.
Eur J Pain ; 22(7): 1255-1267, 2018 08.
Article in English | MEDLINE | ID: mdl-29542208

ABSTRACT

BACKGROUND: Fibromyalgia is a complex chronic disorder with few effective treatments currently available. One promising treatment option is repetitive transcranial magnetic stimulation (rTMS), a non-invasive brain stimulation technique that has shown promise in disorders effecting the central nervous system. METHODS: We assessed the efficacy of a course of high-frequency (10 Hz) left-hemisphere dorsolateral prefrontal cortex (DLPFC) rTMS in 26 patients (14 active; 12 sham) with a diagnosis of fibromyalgia. Participants underwent a double-blind stimulation protocol of daily (Monday-Friday) rTMS sessions over four consecutive weeks (total of 20 sessions; 75 × 4-s 10 Hz trains at 120% resting motor threshold). Assessments were conducted at baseline, 4 weeks and at 1-month follow-up. RESULTS: Using mixed-model analysis we did not identify a group difference for our primary outcome measures. However, we found that patients in the active group compared to sham treatment group had significantly greater improvement in the Physical Fatigue (p = 0.045) and General Fatigue (p = 0.023) scales of the Multidimensional Fatigue Inventory-20 at the 1 month follow-up. In a responder analysis, we also found the active group was significantly more likely (2.84 times) to achieve a minimum 30% improvement in pain intensity ratings. (p = 0.024). CONCLUSIONS: High-frequency rTMS applied daily for 4 weeks to the left DLPFC induces significant relief from fatigue and a greater chance of clinically meaningful improvement in pain intensity in patients with fibromyalgia. These results suggest DLPFC rTMS may be a relevant therapy for fibromyalgia. SIGNIFICANCE: This study provides evidence that 4-weeks of daily rTMS to the left DLPFC is able to improve fatigue in fibromyalgia. This novel finding provides impetus for the further investigation of the utility of TMS approaches for the relief of fatigue, an otherwise difficult-to-treat symptom, in fibromyalgia and related disorders.


Subject(s)
Fatigue/therapy , Fibromyalgia/therapy , Prefrontal Cortex , Transcranial Magnetic Stimulation/methods , Adult , Chronic Disease , Double-Blind Method , Fatigue/complications , Fatigue/etiology , Female , Humans , Male , Middle Aged , Pain Measurement , Treatment Outcome
3.
Brain Stimul ; 11(1): 190-203, 2018.
Article in English | MEDLINE | ID: mdl-29128490

ABSTRACT

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for depression, but only some individuals respond. Predicting response could reduce patient and clinical burden. Neural activity related to working memory (WM) has been related to mood improvements, so may represent a biomarker for response prediction. PRIMARY HYPOTHESES: We expected higher theta and alpha activity in responders compared to non-responders to rTMS. METHODS: Fifty patients with treatment resistant depression and twenty controls performed a WM task while electroencephalography (EEG) was recorded. Patients underwent 5-8 weeks of rTMS treatment, repeating the EEG at week 1 (W1). Of the 39 participants with valid WM-related EEG data from baseline and W1, 10 were responders. Comparisons between responders and non-responders were made at baseline and W1 for measures of theta (4-8 Hz), upper alpha (10-12.5 Hz), and gamma (30-45 Hz) power, connectivity, and theta-gamma coupling. The control group's measures were compared to the depression group's baseline measures separately. RESULTS: Responders showed higher levels of WM-related fronto-midline theta power and theta connectivity compared to non-responders at baseline and W1. Responder's fronto-midline theta power and connectivity was similar to controls. Responders also showed an increase in gamma connectivity from baseline to W1, with a concurrent improvement in mood and WM reaction times. An unbiased combination of all measures provided mean sensitivity of 0.90 at predicting responders and specificity of 0.92 in a predictive machine learning algorithm. CONCLUSION: Baseline and W1 fronto-midline theta power and theta connectivity show good potential for predicting response to rTMS treatment for depression.


Subject(s)
Depression/physiopathology , Depression/therapy , Theta Rhythm/physiology , Transcranial Magnetic Stimulation , Adolescent , Adult , Affect , Aged , Case-Control Studies , Depression/psychology , Depressive Disorder/physiopathology , Depressive Disorder/psychology , Depressive Disorder/therapy , Electroencephalography , Female , Humans , Male , Memory, Short-Term , Middle Aged , Reaction Time , Treatment Outcome , Young Adult
4.
Bone Joint J ; 98-B(10): 1320-1325, 2016 Oct.
Article in English | MEDLINE | ID: mdl-27694584

ABSTRACT

As residency training programmes around the globe move towards competency-based medical education (CBME), there is a need to review current teaching and assessment practices as they relate to education in orthopaedic trauma. Assessment is the cornerstone of CBME, as it not only helps to determine when a trainee is fit to practice independently, but it also provides feedback on performance and guides the development of competence. Although a standardised core knowledge base for trauma care has been developed by the leading national accreditation bodies and international agencies that teach and perform research in orthopaedic trauma, educators have not yet established optimal methods for assessing trainees' performance in managing orthopaedic trauma patients. This review describes the existing knowledge from the literature on assessment in orthopaedic trauma and highlights initiatives that have recently been undertaken towards CBME in the United Kingdom, Canada and the United States. In order to support a CBME approach, programmes need to improve the frequency and quality of assessments and improve on current formative and summative feedback techniques in order to enhance resident education in orthopaedic trauma. Cite this article: Bone Joint J 2016;98-B:1320-5.


Subject(s)
Clinical Competence/standards , Competency-Based Education/methods , Education, Medical, Graduate/methods , Internship and Residency , Orthopedics/education , Physicians/standards , Wounds and Injuries , Canada , Humans , United Kingdom , United States
5.
Bone Joint J ; 95-B(11): 1445-9, 2013 Nov.
Article in English | MEDLINE | ID: mdl-24151260

ABSTRACT

Valid and reliable techniques for assessing performance are essential to surgical education, especially with the emergence of competency-based frameworks. Despite this, there is a paucity of adequate tools for the evaluation of skills required during joint replacement surgery. In this scoping review, we examine current methods for assessing surgeons' competency in joint replacement procedures in both simulated and clinical environments. The ability of many of the tools currently in use to make valid, reliable and comprehensive assessments of performance is unclear. Furthermore, many simulation-based assessments have been criticised for a lack of transferability to the clinical setting. It is imperative that more effective methods of assessment are developed and implemented in order to improve our ability to evaluate the performance of skills relating to total joint replacement. This will enable educators to provide formative feedback to learners throughout the training process to ensure that they have attained core competencies upon completion of their training. This should help ensure positive patient outcomes as the surgical trainees enter independent practice.


Subject(s)
Arthroplasty, Replacement/education , Clinical Competence , Education, Medical, Graduate/methods , Physicians/standards , Humans , Reproducibility of Results
6.
Gen Comp Endocrinol ; 114(1): 11-8, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10094854

ABSTRACT

Plasma levels of sex steroids (progesterone, 17alpha-hydroxyprogesterone, total androgens, and estradiol) were measured at six stages from courtship to late incubation in Adélie penguins. The pattern of change detected in the levels of plasma total androgens (males) and estradiol (females) was consistent with that found in many birds, with elevated levels during courtship (total androgens, 4 ng/ml; estradiol, 0.5 ng/ml) declining to low, stable levels during incubation. Progesterone levels declined moderately from 1.3 to 0.75-1.0 ng/ml in females following egg laying, but levels of 0.8-1.2 ng/ml persisted in males throughout the study period. 17alpha-Hydroxyprogesterone levels were consistently low (approximately 0.2 ng/ml) in females but progressively declined in males from 0.75 during courtship to <0.3 ng/ml at egg laying and during foraging. Plasma corticosterone levels were measured over the same period and were elevated in both males and females at courtship (16-18 ng/ml) and while fasting on the nest (11-15 ng/ml), but had declined in birds returning from foraging at sea, suggesting that elevated levels are related to the metabolic demands of fasting.


Subject(s)
Birds/blood , Corticosterone/blood , Gonadal Steroid Hormones/blood , Sexual Behavior, Animal , 17-alpha-Hydroxyprogesterone/blood , Androgens/blood , Animals , Courtship , Estradiol/blood , Progesterone/blood
7.
Environ Mol Mutagen ; 32(2): 173-8, 1998.
Article in English | MEDLINE | ID: mdl-9776180

ABSTRACT

Previously, we determined that elimination of deoxycytidylate (dCMP) deaminase (DCD1) in the yeast Saccharomyces cerevisiae increases the intracellular dCTP:dTTP ratio and reduces the induction of G x C --> A x T transitions in the SUP4-o gene by ethyl methanesulfonate (EMS) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Simultaneously, the G x C --> C x G transversion frequency rises substantially. We attributed the first response to dCTP outcompeting dTTP for incorporation opposite O6-alkylguanine, and the second outcome to the increased dCTP pool causing error-prone repair of apurinic (AP) sites resulting from the removal or lability of N7-alkylguanine. To test the latter hypothesis, we used isogenic dcd1 strains deleted for either of two genes (MAG1: 3-methyladenine glycosylase; APN1: apurinic endonuclease) involved in the repair of N7-alkylguanine. In these backgrounds, EMS or MNNG induction of total SUP4-o mutations, G x C --> A x T transitions and G x C --> C x G transversions were reduced by >98%, >97%, and >80%, respectively. Mutation frequencies in the dcd1 apn1 strain were close to those for spontaneous mutagenesis in the wild-type parent. These findings argue that misincorporation of dCTP during repair of alkylation-induced AP sites is responsible for the increased G x C --> C x G transversion frequency in the dcd1 strain treated with EMS or MNNG. The data also demonstrate that defective repair of AP sites coupled with an elevated dCTP:dTTP ratio eliminates most EMS and MNNG mutagenesis. In addition, the results point to a role for AP sites in the production of some EMS- and MNNG-induced G x C --> A x T transitions as well as other substitutions in the dcd1 strain.


Subject(s)
Alkylating Agents/toxicity , Carbon-Oxygen Lyases/physiology , DNA Glycosylases , DNA Ligases/physiology , DNA Repair , DNA, Fungal/drug effects , Deoxycytosine Nucleotides/pharmacology , Ethyl Methanesulfonate/antagonists & inhibitors , Fungal Proteins/physiology , Methylnitronitrosoguanidine/toxicity , Mutagenesis/drug effects , N-Glycosyl Hydrolases/physiology , Saccharomyces cerevisiae/drug effects , Alkylation , Carbon-Oxygen Lyases/deficiency , Carbon-Oxygen Lyases/genetics , DNA Adducts/metabolism , DNA Damage , DNA Ligases/deficiency , DNA Ligases/genetics , DNA Repair/drug effects , DNA Repair/genetics , DNA, Fungal/genetics , DNA, Fungal/metabolism , DNA-(Apurinic or Apyrimidinic Site) Lyase , Deoxyribonuclease IV (Phage T4-Induced) , Ethyl Methanesulfonate/toxicity , Fungal Proteins/genetics , Genes, Suppressor/drug effects , Intracellular Fluid , N-Glycosyl Hydrolases/deficiency , N-Glycosyl Hydrolases/genetics
8.
Lab Invest ; 77(5): 533-9, 1997 Nov.
Article in English | MEDLINE | ID: mdl-9389796

ABSTRACT

Basement membranes form a boundary between intravascular and extravascular compartments that is remodeled by matrix metalloproteinases (MMP) expressed by endothelial cells. These cells are at risk of exposure to reactive oxygen intermediates generated as a consequence of interactions with drugs, x-radiation, activated neutrophils, or cancer cells. Herein we have investigated the hypothesis that endothelial cells alter their expression of MMP after sublethel exposure to H2O2 and that this leads to degradation of adjacent basement membranes. Cultured human umbilical vein endothelial cells were treated with concentrations of H2O2 ranging from 1.5 to 32 microM or with 2 x 10(-6)M phorbol myristate acetate (PMA). After 24 hours, the cells were placed into serum-free medium for an additional 24 hours. This conditioned medium or cell lysates were studied by matrix degradation assays, gelatin zymography, immunoblots, and Northern analysis. H2O2-treated or PMA-treated cells, or their serum-free conditioned medium, caused a 2-fold increase in degradation of [3H]-proline-labeled endothelial basement membranes or purified type IV collagen compared to untreated cells. Endothelial cells constitutively expressed gelatinases at Mr 96,000 and 72,000, consistent with MMP-9 and inactive MMP-2. H2O2 exposure caused increased expression of these MMP and appearance of Mr 64,000 to 66,000 gelatinases corresponding to activated MMP-2. In cell lysates, H2O2 or PMA treatment led to increased expression of membrane-type MMP-1, an activator of latent MMP-2. The results suggest that oxidants such as H2O2 may stimulate MMP expression and influence the remodeling of vascular basement membranes by endothelial cells.


Subject(s)
Endothelium, Vascular/drug effects , Endothelium, Vascular/enzymology , Gelatinases/biosynthesis , Gelatinases/drug effects , Hydrogen Peroxide/toxicity , Metalloendopeptidases/biosynthesis , Metalloendopeptidases/drug effects , Basement Membrane/drug effects , Basement Membrane/enzymology , Blotting, Northern , Blotting, Western , Cells, Cultured , Culture Media, Conditioned/pharmacology , Electrophoresis, Polyacrylamide Gel , Endothelium, Vascular/cytology , Enzyme Activation/drug effects , Gelatinases/metabolism , Humans , Matrix Metalloproteinase 2 , Metalloendopeptidases/metabolism , Umbilical Veins
9.
J Clin Pathol ; 46(4): 352-6, 1993 Apr.
Article in English | MEDLINE | ID: mdl-7684404

ABSTRACT

AIMS: To assess keratin profiles from smears of malignant and contralateral normal oral mucosa as part of the development of a screening procedure for oral cancer based on exfoliative cytology. METHODS: Smears were taken from oral cancers (confirmed by biopsy) and from the contralateral site of 20 patients. Using a panel of antikeratin antibodies, the keratins expressed by these cells were identified using a standard immunocytochemical technique (Vectastain) and assessed on a 3 point scale. RESULTS: Using chi 2 analysis, noticeable differences between the keratin profiles for malignant mucosal smears compared with the contralateral mucosal smears were found. This was particularly evident for the simple epithelial keratins. CONCLUSION: Individual keratins can be identified in smears from oral cancers. The identification of simple epithelial keratins seem to be the best keratin markers associated with malignancy. Their detection within smears from oral lesions could be valuable in the early diagnosis of oral cancer.


Subject(s)
Biomarkers, Tumor/analysis , Keratins/analysis , Mouth Mucosa/chemistry , Mouth Neoplasms/chemistry , Antibodies, Monoclonal/immunology , Humans , Immunoenzyme Techniques , Keratins/immunology , Mouth Neoplasms/diagnosis
10.
Mol Endocrinol ; 7(1): 23-36, 1993 Jan.
Article in English | MEDLINE | ID: mdl-8446105

ABSTRACT

The location and sequence of androgen responsive elements (AREs) in the 5'-flanking DNA of the androgen-regulated rat probasin (PB) gene were determined. The DNA- and steroid-binding domains of the rat androgen receptor [glutathione-S-transferase (GST)-AR1] and the DNA-binding domain and hinge region alone (GST-AR2) were expressed in Escherichia coli as isopropyl-B-D-thioglactopyranoside-induced fusion proteins with GST and purified using glutathione affinity chromatography. Band shift assays indicated that the AR1 peptide was at least five times more effective than AR2 in binding to PB 5'-flanking DNA (-426 to +28), although both gave qualitatively similar patterns and were displaced by anti-AR antibodies. DNase I footprinting experiments revealed two putative AREs: one between positions -236 and -223 (ARE-1) and the other between -140 and -117 (ARE-2). Hormonal regulation of PB was determined by cotransfecting reporter constructions containing the PB 5'-flanking region (-426 to +28) linked to the bacterial chloramphenicol acetyl transferase (CAT) gene with androgen, glucocorticoid, or progesterone receptor expression vectors into human prostatic carcinoma cells (PC-3). PB-CAT gene expression was more effectively induced by androgens than by glucocorticoids or progestins. Both 5'- and 3'-deletion mapping of the PB 5'-flanking DNA revealed that ARE-1 and ARE-2 were required for androgen regulation. A single base mutation in either ARE resulted in a more than 95% loss of androgen induction of CAT. In comparable transfection experiments, the PB hormone-responsive elements showed a greater induction by androgens than did mouse mammary tumor virus or tyrosine aminotransferase elements. Thus, the preferential androgen regulation of the PB gene involves the participation of two different cis-acting DNA elements that bind AR.


Subject(s)
Androgen-Binding Protein/genetics , Androgens/pharmacology , DNA-Binding Proteins/metabolism , Receptors, Androgen/metabolism , Recombinant Fusion Proteins/metabolism , Regulatory Sequences, Nucleic Acid , Transcription Factors/metabolism , Transcription, Genetic/drug effects , Amino Acid Sequence , Androgen-Binding Protein/biosynthesis , Animals , Base Sequence , Cell Line , Consensus Sequence , DNA-Binding Proteins/genetics , Gene Expression Regulation/drug effects , Genes , Genes, Synthetic , HeLa Cells , Humans , Isopropyl Thiogalactoside/pharmacology , Molecular Sequence Data , Rats , Receptors, Androgen/genetics , Receptors, Glucocorticoid/genetics , Receptors, Glucocorticoid/metabolism , Receptors, Progesterone/genetics , Receptors, Progesterone/metabolism , Sequence Homology, Nucleic Acid , Transcription Factors/genetics
11.
Gene ; 122(2): 271-9, 1992 Dec 15.
Article in English | MEDLINE | ID: mdl-1336755

ABSTRACT

The combination of transcriptional and translational control elements in an inducible expression vector suitable for use in stably transformed cell lines was explored. To this end, ferritin translational control elements have been inserted downstream from a mouse metallothionein (mMT-I) transcriptional promoter (PmMT-I), and upstream from various reporter protein-encoding open reading frames (ORFs), all carried on a bovine papillomavirus shuttle vector. Protocols which stimulate transcription (with zinc) and translation (with iron) were developed to optimize the induction of reporter protein synthesis. It was found that insertion of an iron regulatory element between the PmMT-I and a reporter ORF bestowed a sixfold inducibility of reporter protein synthesis with iron and a 90-fold inducibility with iron plus zinc in a classical superinduction protocol. Surprisingly, inclusion of other rabbit ferritin light chain sequences (rFL), including the ORF, enhanced reporter inducibilities to over 15- and 500-fold, respectively. These additional rFL sequences not only increased inducibility but also (i) increased the half-life of the mRNA and (ii) strongly inhibited translation of an ORF located downstream from the 5' proximal ORF. The maximum levels of reporter proteins attained in transformed cells after prolonged induction represented from 1% to 7% of total cellular protein. These inducible expression vectors should prove useful for the production and study of cytotoxic proteins.


Subject(s)
Bovine papillomavirus 1/genetics , Ferritins/genetics , Genetic Vectors , Protein Biosynthesis , Animals , Cell Line , DNA , Electrophoresis, Polyacrylamide Gel , Encephalomyocarditis virus/genetics , Gene Expression Regulation, Viral , Mice , Open Reading Frames , Promoter Regions, Genetic , RNA, Messenger/metabolism , Regulatory Sequences, Nucleic Acid , Transcription, Genetic
12.
Science ; 256(5057): 670-3, 1992 May 01.
Article in English | MEDLINE | ID: mdl-1316633

ABSTRACT

Induction of ferritin synthesis in cultured cells by heme or iron is accompanied by degradation of the ferritin repressor protein (FRP). Intermediates in the degradative pathway apparently include FRP covalently linked in larger aggregates. The effect of iron on FRP degradation is enhanced by porphyrin precursors but is decreased by inhibitors of porphyrin synthesis, which implies that heme is an active agent. These results suggest that translational induction in this system may be caused by enhanced repressor degradation. While unique among translational regulatory systems, this process is common to a variety of other biosynthetic control mechanisms.


Subject(s)
Ferritins/genetics , Protein Biosynthesis , RNA, Messenger/genetics , RNA-Binding Proteins/metabolism , 5-Aminolevulinate Synthetase/genetics , Aminolevulinic Acid/pharmacology , Animals , Cell Line , Cell Line, Transformed , Ferritins/biosynthesis , Fibroblasts/metabolism , Iron/pharmacology , Iron Regulatory Protein 1 , Iron-Regulatory Proteins , Mice , Papillomaviridae , Porphobilinogen/pharmacology , Rabbits
13.
Histochem J ; 24(3): 176-9, 1992 Mar.
Article in English | MEDLINE | ID: mdl-1374749

ABSTRACT

The identification of keratin expression within oral cytology may be useful in the diagnosis of clinically suspicious oral mucosal lesions. There may be wide variation in the temperature at which such smears are stored, prior to processing. Conventionally, rapid fixation or storage at low temperatures is recommended to preserve kertin expression within tissue biopsies. No previous study has assessed whether this is true for oral cytology. Smears were taken from clinically normal buccal mucosa. For each temperature assessed (-70, -40, -22, +5, +20 and +26 degrees C), one smear was spray-fixed (Vale Smear Fix) and one air-dried, prior to storage for 4 days, and then staining with the pan-epithelial antikeratin antibody, LP34. Preservation of keratin expression was assessed as either weak (zero to few positive cells) or strong (most cells positive). The results were analysed using logistic regression with the statistical modelling package, GLIM. Over the range of temperatures studied, spray fixation did not appear to improve the identification of keratin expression. Although the best preservation was obtained at lower temperatures, keratin expression was still adequate after 4 days at 20 degrees C. Hence, a delay in processing of 4 days would still allow detectable expression in oral exfoliative cytology even at room temperature.


Subject(s)
Keratins/analysis , Mouth Mucosa/chemistry , Temperature , Adolescent , Adult , Humans , Tissue Fixation
14.
Biochim Biophys Acta ; 1050(1-3): 146-50, 1990 Aug 27.
Article in English | MEDLINE | ID: mdl-2169889

ABSTRACT

We have previously reported that hemin derepresses ferritin mRNA translation in vitro. As noted earlier, pre-incubation of a 90 kDa ferritin repressor protein (FRP) with hemin prevented subsequent repression of ferritin synthesis in a wheat germ extract. The significance of this observation has been investigated further. Evidence is presented here that this inactivation of FRP is temperature dependent. Neither FeCl3, Fe3+ chelated with EDTA, nor protoporphyrin IX caused significant inactivation of FRP under comparable conditions, whereas Zn2(+)-protoporphyrin IX produced an intermediate degree of inhibition. The presence of a glutathione redox buffer (GSB), which was previously shown to minimize non-specific side-effects of hemin, was not necessary for the derepression reaction. Inclusion of mannitol, a free radical scavenger, did not alter the inactivation caused by hemin. Calculation of the expected ratio of hemin monomers to dimers suggests that the active species is the monomer.


Subject(s)
Carrier Proteins/metabolism , Ferritins/genetics , Heme/pharmacology , Protein Biosynthesis/drug effects , Reticulocytes/metabolism , Animals , Apolipoprotein A-I , Apolipoproteins A/genetics , Chlorides , DNA Restriction Enzymes/metabolism , Edetic Acid/pharmacology , Ferric Compounds/pharmacology , Ferritins/biosynthesis , Ferrous Compounds/pharmacology , Humans , Iron Regulatory Protein 1 , Iron-Regulatory Proteins , Kinetics , Lipoproteins, HDL/genetics , RNA, Messenger/drug effects , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rabbits , Thermodynamics
15.
Science ; 247(4938): 74-7, 1990 Jan 05.
Article in English | MEDLINE | ID: mdl-2294594

ABSTRACT

Incubation of a 90-kilodalton ferritin repressor protein (FRP), either free or complexed with an L-ferritin transcript, with hemin or Co3+-protoporphyrin IX prevented subsequent repression of ferritin synthesis in a wheat germ extract. Neither FeCl3 in combinations with H2O2, nor Fe3+ or Fe2+ chelated with EDTA, nor Zn2+-protoporphyrin IX, nor protoporphyrin IX caused significant inactivation of FRP. FRP that had been inactivated by hemin remained chemically intact, as revealed by SDS-polyacrylamide gel electrophoresis. Inclusion of chelators of iron or free radical scavengers did not alter the inactivation produced by hemin. These and other results indicate that hemin derepresses ferritin synthesis in vitro.


Subject(s)
Ferritins/genetics , Heme/analogs & derivatives , Hemin/pharmacology , Protein Biosynthesis/drug effects , RNA, Messenger/genetics , Repressor Proteins/genetics , Transcription Factors/genetics , Binding Sites , Binding, Competitive , Electrophoresis, Polyacrylamide Gel , Ferritins/biosynthesis , Free Radicals , Iron Chelating Agents/pharmacology , Protoporphyrins/metabolism , Repressor Proteins/metabolism
16.
J Biol Chem ; 264(23): 13383-6, 1989 Aug 15.
Article in English | MEDLINE | ID: mdl-2760024

ABSTRACT

A specific repressor of ferritin mRNA translation originally detected in rabbit reticulocyte lysates has now been purified to homogeneity from rabbit liver, as described in a companion paper (Walden, W. E., Patino, M. M., and Gaffield, L. (1989) J. Biol. Chem. 264, 13765-13769). This repressor is a 90-kDa protein that binds to a sequence in the 5'-untranslated region of ferritin mRNA. In this communication we describe the molecular features of a ferritin light chain transcript that are required for the repression of its translation by this protein. Addition of small amounts of the 90-kDa ferritin repressor protein (FRP) completely inhibited translation of ferritin transcripts in a wheat germ system. This repression did not require mRNA sequences contained in the 3'-untranslated region or in the majority of the ferritin coding region. In contrast, the first 130 nucleotides of the 5'-untranslated region, which contains the 28-nucleotide "iron responsive element" (IRE), was required for the repressive effect. Moreover, repression of full length transcripts was relieved by addition of a molar excess of a 92-nucleotide transcript of the 5'-untranslated region which also contained the IRE. These results suggest that no sequence information other than a portion of the 5'-untranslated region containing the IRE sequence is required for action of the 90-kDa FRP. In addition, a quantitative comparison of the repression of transcript with that of poly(A+) RNAs indicates that no post-transcriptional modifications of the latter (other than cap addition) are involved in the action of the 90-kDa FRP.


Subject(s)
Ferritins/genetics , Liver/physiology , Plants/metabolism , Protein Biosynthesis/drug effects , Protein Synthesis Inhibitors , Proteins/isolation & purification , Transcription, Genetic , Animals , Base Sequence , Molecular Sequence Data , Molecular Weight , Proteins/pharmacology , RNA, Messenger/genetics , Rabbits , Triticum/metabolism
17.
Proc Natl Acad Sci U S A ; 85(24): 9503-7, 1988 Dec.
Article in English | MEDLINE | ID: mdl-3200835

ABSTRACT

Mouse and rabbit ferritin mRNAs translate very poorly in rabbit reticulocyte lysates relative to most other mRNAs. This translational deficiency is not seen in wheat germ lysates, suggesting the presence of an inhibitor in reticulocyte lysate that is specific for ferritin mRNA. A specific repressor of ferritin mRNA translation has been partially purified from rabbit reticulocytes by differential ultracentrifugation, ammonium sulfate fractionation, and chromatography on phosphocellulose, DEAE-cellulose, and Sephacryl S-300. The elution profile from the latter suggests an aggregate molecular mass of approximately 180 kDa for the repressor. The inhibitory activity of this repressor against native ferritin mRNA can be relieved by adding in vitro transcripts of ferritin light-chain RNAs that contain the first 92 nucleotides of the 5' untranslated region. No other sequences appear to be necessary for this effect.


Subject(s)
Ferritins/genetics , Protein Biosynthesis , RNA, Messenger/metabolism , Repressor Proteins/isolation & purification , Transcription Factors/isolation & purification , Animals , Chromatography, DEAE-Cellulose , Chromatography, Gel , Mice , Molecular Weight , Rabbits , Reticulocytes/analysis , Ultracentrifugation
19.
Acta Cytol ; 32(1): 91-3, 1988.
Article in English | MEDLINE | ID: mdl-2447727

ABSTRACT

Fine needle aspiration cytology was used to study chest wall nodules in a patient who presented with fever, cough, pleuritic chest pain and cytomegalovirus infection and who had a previous history of abdominal trauma. The finding of splenic red pulp and white pulp in the aspirate, combined with the results of a radionucleotide liver-spleen scan, led to a diagnosis of thoracic splenosis, a relatively rare condition. Splenosis is thought to result from transplantation of splenic tissue after trauma and may provide some added protection against certain infectious conditions, both of which were present in this case.


Subject(s)
Splenic Diseases/pathology , Thoracic Diseases/pathology , Biopsy, Needle , Female , Humans , Middle Aged , Radionuclide Imaging , Spleen/pathology , Splenic Diseases/diagnosis , Splenic Diseases/diagnostic imaging , Staining and Labeling , Thoracic Diseases/diagnosis , Thoracic Diseases/diagnostic imaging
20.
J Biol Chem ; 262(29): 14197-203, 1987 Oct 15.
Article in English | MEDLINE | ID: mdl-3115988

ABSTRACT

The gonadotropins luteinizing hormone, follicle-stimulating hormone, and human chorionic gonadotropin are composed of two noncovalently linked subunits, alpha and beta. The alpha subunit, identical in all three hormones, is produced in excess over the unique beta subunits by pituitary and placenta, and is secreted as uncombined, or free subunit. Free alpha subunit from both tissues has a larger molecular weight than the dimer form. In bovine pituitary an extra O-linked oligosaccharide is added to free alpha subunit, and this modification has recently been detected at an analogous position (threonine 39) on human alpha subunit secreted by choriocarcinoma cells. To assess the contribution of N-linked and O-linked oligosaccharides to the heterogeneity of human free alpha subunit, we have compared free alpha with human chorionic gonadotropin alpha secreted by explants and cultured cytotrophoblasts of human first trimester placenta. We have also examined the free and combined forms of human alpha subunit expressed in transfected C-127 mouse mammary tumor cells. Processing of the alpha subunit in placental and C-127 cells was similar. Tryptic mapping of placental-derived and transfected alpha subunits indicated that O-glycosylation at threonine 39 was not a major modification. In the presence of the oligosaccharide processing inhibitor swainsonine the difference in size between the free and combined forms of alpha was eliminated in both placental and C-127 cells, indicating that the two forms of alpha differed in their N-linked oligosaccharides. Furthermore, the oligosaccharides of free alpha subunits from placental and transfected cells were resistant to endoglycosidase H, but the combined forms of alpha were partially sensitive to the enzyme. Thus, in human first trimester placenta and mouse C-127 cells, combination of alpha with human chorionic gonadotropin beta alters the processing of N-linked oligosaccharides on alpha subunit.


Subject(s)
Chorionic Gonadotropin/genetics , Follicle Stimulating Hormone/genetics , Luteinizing Hormone/genetics , Protein Processing, Post-Translational , Trophoblasts/metabolism , Alkaloids/pharmacology , Animals , Cells, Cultured , Chorionic Gonadotropin/biosynthesis , Female , Follicle Stimulating Hormone/biosynthesis , Genetic Vectors , Humans , Luteinizing Hormone/biosynthesis , Macromolecular Substances , Mice , Organ Culture Techniques , Placenta/metabolism , Pregnancy , Recombination, Genetic , Swainsonine
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