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1.
J Endocrinol Invest ; 43(10): 1493-1498, 2020 Oct.
Article in English | MEDLINE | ID: mdl-32253728

ABSTRACT

PURPOSE: The true association between primary hyperparathyroidism (PHPT) and pancreatitis continues to be controversial. In this study, we present clinical data, investigative profile, management and follow-up of PHPT patients with pancreatitis and compare this group with PHPT patients without pancreatitis. METHODS: Records of 242 patients with PHPT managed at our center over 24 years were retrospectively analyzed for demographic and laboratory data. The diagnosis of pancreatitis was entertained in the presence of at least two of the three following features: abdominal pain, levels of serum amylase greater than three times the normal or characteristic features at imaging. RESULTS: Fifteen (6.19%) of the 242 consecutive patients with PHPT had had pancreatitis. Fourteen patients (93.3%) had acute pancreatitis (AP), while one patient had chronic calcific pancreatitis. Over half (8 of 14) of the patients with AP had at least two episodes of pancreatitis. Pancreatitis was the presenting symptom in 14 (93.3%) patients. None of the pancreatitis cases had additional risk factors for pancreatitis. PHPT patients with pancreatitis had significantly higher serum calcium and ALP than PHPT patients without pancreatitis. After successful parathyroidectomy, 14 patients had no further attacks of pancreatitis during a median follow-up of 16 months (range 2-41 months), while recurrence of pancreatitis was seen in one patient. CONCLUSIONS: We conclude that pancreatitis can be the only presenting complaint of PHPT. Our study highlights the importance of fully investigating for PHPT in any pancreatitis patient with high normal or raised serum calcium level, especially in the absence of other common causes of pancreatitis.


Subject(s)
Hyperparathyroidism, Primary/complications , Pancreatitis/complications , Adult , Aged , Calcium/blood , Case-Control Studies , Child , Diagnosis, Differential , Female , Humans , Hyperparathyroidism, Primary/diagnosis , Hyperparathyroidism, Primary/epidemiology , Hyperparathyroidism, Primary/therapy , Male , Middle Aged , Pancreatitis/diagnosis , Pancreatitis/epidemiology , Pancreatitis/therapy , Parathyroid Hormone/blood , Parathyroidectomy , Retrospective Studies , Young Adult
2.
Indian J Cancer ; 51(2): 133-7, 2014.
Article in English | MEDLINE | ID: mdl-25104194

ABSTRACT

BACKGROUND: An assessment of cancer incidence in population is required for prevention, early diagnosis, treatment and resource allocation. This will also guide in the formation of facilities for diagnosis, treatment, rehabilitation and follow-up for these patients. The demographic trend of cancer will help to identify common types and etiological factors. Efforts at clinical, research and administrative levels are needed to overcome this problem. SETTINGS AND DESIGN: Present retro prospective study was conducted in regional cancer center of a tertiary care hospital. MATERIALS AND METHODS: After permission from ethics committee, a retro prospective study of 1 year duration was undertaken to study the profile of cancer patients and to compare it with other cancer registries in India. STATISTICAL ANALYSIS: Pearson's Chi-square test and simple linear regression were used. Statistical Package for the Social Sciences version-16 (University of Bristol information services (www.bristol.ac.uk/is/learning/resources) was used. RESULTS: The overall incidence of cancer in Kashmir is on the increase and common sites of cancer are esophagus and gastroesophageal (GE) junction, lung, stomach, colorectal, lymphomas, skin, laryngopharynx, acute leukemias, prostate and brain in males.In females common sites are breast, esophagus and GE junction, ovary, colorectal, stomach, lung, gallbladder, lymphomas, acute leukemias and brain. CONCLUSION: Cancers of esophagus, stomach and lungs have a high incidence both in men and women in Kashmir. Future studies on sources and types of environmental pollution and exposures in relation to these cancers may improve our understanding of risk factors held responsible for causation of these malignancies in this region. This will help in the allocation of available resources for prevention and treatment strategies.


Subject(s)
Neoplasms/epidemiology , Age Distribution , Female , Humans , Incidence , India/epidemiology , Male , Registries , Sex Distribution
3.
Indian J Pediatr ; 78(3): 287-90, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21046287

ABSTRACT

OBJECTIVE: Appendicitis is the most common abdominal emergency usually requiring surgery in the pediatric age group. Diagnosis of acute appendicitis can at times be difficult, especially in children. A failure to diagnose can lead to a progression of disease with its associated morbidity and mortality. The authors used a modification of Alvarado scoring system which consists of eight variables and would provide an accurate guide to the preoperative diagnosis of acute appendicitis leading to proper and timely management. METHODS: This was a prospective study conducted from Jan 2005 through Dec 2006 and included 90 consecutive patients with suspected acute appendicitis. They were given specific scores according to variables of scoring system and divided into 3 groups. Group III patients (score 7 or more) underwent surgery, group II (score 5-6) were admitted for close observation and group I (score 4 or less) were discharged home. Patients from group II with increased symptom intensity (score 7 or more) on re-evaluation underwent surgery. Diagnosis was confirmed by operative findings and histopathological examination. Reliability of scoring system was assessed by calculating negative appendicectomy rate and positive predictive value. RESULTS: Out of total 90 patients, 73 patients underwent surgery and appendicitis was confirmed in 68 cases. The negative appendicectomy rate was 6.84%, perforation rate was 36.9%. Positive predictive value was 93.1%. CONCLUSIONS: Our scoring system is useful as a first line, rapid, reliable and economic way of early preoperative diagnosis of acute appendicitis in children and in reducing the incidence of negative appendicectomy rate.


Subject(s)
Appendicitis/diagnosis , Severity of Illness Index , Adolescent , Appendectomy , Appendicitis/surgery , Child , Child, Preschool , Early Diagnosis , Female , Humans , Male , Predictive Value of Tests , Prospective Studies , Sensitivity and Specificity
4.
Pediatr Neurosurg ; 46(1): 25-8, 2010.
Article in English | MEDLINE | ID: mdl-20453560

ABSTRACT

OBJECTIVES: The aim of this study was to assess the head injury in children caused by an unusual projectile, a tear gas cartridge. The study is the only one on this subject which has been done in a teenage population. METHOD: This was a prospective study conducted over a period of 4 years in which all the patients aged less than or equal to 18 years and who had a head injury due to a tear gas cartridge were included. RESULTS: We had 5 patients in our study group. All the patients were males. Commonest CT scan finding was brain contusion with skull fracture. One of our patients died. One patient continues to be in vegetative state whereas 3 had a good outcome. CONCLUSION: Tear gas cartridge, though considered as one of the benign modalities of controlling agitated crowds, is not really benign. It can cause serious injuries and mortality. The personnel using them might be trained in a better way so that the people do not receive direct hits. In addition some changes in the design of tear gas cartridge can be done to decrease the impact to the skull.


Subject(s)
Skull Fracture, Depressed/etiology , Skull Fracture, Depressed/mortality , Subarachnoid Hemorrhage, Traumatic/etiology , Subarachnoid Hemorrhage, Traumatic/mortality , Tear Gases/adverse effects , Adolescent , Glasgow Coma Scale , Hematoma, Epidural, Cranial/diagnostic imaging , Hematoma, Epidural, Cranial/etiology , Hematoma, Epidural, Cranial/mortality , Humans , India/epidemiology , Male , Morbidity , Prospective Studies , Skull Fracture, Depressed/diagnostic imaging , Subarachnoid Hemorrhage, Traumatic/diagnostic imaging , Tomography, X-Ray Computed
5.
Indian J Med Microbiol ; 28(2): 169-71, 2010.
Article in English | MEDLINE | ID: mdl-20404469

ABSTRACT

Invasive listeriosis predominantly affects pregnant women, neonates, elderly and people with a compromised immune function. For more than 80 years since the discovery of Listeria in 1924, only a few reports of invasive listeriosis in humans have emerged from India, with all of them in patients having an underlying predisposition. We, however, report Listeria monocytogenes meningoencephalitis in an immunocompetent, previously healthy, 20-month-old female child with no underlying predisposition. The patient showed poor response to empirical treatment with vancomycin and ceftriaxone but improved dramatically after substitution with ampicillin and amikacin. She had a complete recovery other than left lateral rectus palsy that persisted.


Subject(s)
Listeria monocytogenes/isolation & purification , Meningitis, Listeria/diagnosis , Anti-Bacterial Agents/therapeutic use , Female , Humans , India , Infant , Meningitis, Listeria/complications , Meningitis, Listeria/drug therapy , Meningitis, Listeria/microbiology , Paralysis , Treatment Outcome
7.
Postgrad Med J ; 80(945): 415-9, 2004 Jul.
Article in English | MEDLINE | ID: mdl-15254307

ABSTRACT

BACKGROUND: The introduction of intranet services in a district general hospital provided an opportunity to put evidence based national guidelines online to facilitate access and promote application of best practice in acute medical care. This study evaluated the effectiveness of this approach. METHOD: Local guidelines were made available online at ward terminals after they had been distributed in paper form. An interrupted time series design was used to evaluate the impact on compliance with three preselected guidelines, which addressed the management of suspected deep vein thrombosis, upper gastrointestinal bleeding, and stroke. This was supplemented by a qualitative assessment of the views of medical staff. RESULTS: There was a significant increase in the adherence to the guidelines for stroke when they were made available online, but this was not demonstrable for deep vein thrombosis or upper gastrointestinal bleeding. Qualitative interviews with junior medical staff and consultants after the study was completed revealed that there was confusion regarding the application of the guidelines for deep vein thrombosis and little active support from the gastroenterologists for the guidelines for upper gastrointestinal bleeding. The stroke guidelines were actively promoted by their author and widely supported. CONCLUSION: Making guidelines available online will not be effective unless they are actively promoted and represent a consensus view.


Subject(s)
Guideline Adherence/standards , Internet , Practice Guidelines as Topic/standards , Professional Practice/standards , Venous Thrombosis/therapy , Algorithms , Attitude of Health Personnel , Evidence-Based Medicine , Guideline Adherence/statistics & numerical data , Hospitals, District , Humans , Medical Staff, Hospital , Wales
8.
Neurol India ; 50(2): 217-9, 2002 Jun.
Article in English | MEDLINE | ID: mdl-12134196

ABSTRACT

The occurrence of bilateral extradural hematomas is an uncommon consequence of craniocerebral trauma and its incidence is variable in various studies ranging from 2-25%.1 We studied all cases of head injury brought to our institute over a period of 6 months and found the incidence of bilateral extradural hematomas to be 13.3%.


Subject(s)
Craniocerebral Trauma/complications , Hematoma, Epidural, Cranial/epidemiology , Hematoma, Epidural, Cranial/etiology , Adult , Child , Hematoma, Epidural, Cranial/diagnostic imaging , Humans , Incidence , India , Retrospective Studies , Tomography, X-Ray Computed
9.
Pediatr Surg Int ; 18(2-3): 171-2, 2002 Mar.
Article in English | MEDLINE | ID: mdl-11956789

ABSTRACT

Protrusion of a ventriculoperitoneal (VP) shunt through the umblicus is one of the rare complications of shunt insertion reported in the medical literature. One such case is presented here in a child in whom a VP shunt had been placed for congenital hydrocephalus.


Subject(s)
Foreign-Body Migration , Umbilicus , Ventriculoperitoneal Shunt/adverse effects , Abdominal Pain/etiology , Female , Foreign-Body Migration/surgery , Humans , Hydrocephalus/surgery , Infant
10.
Neurol India ; 49(2): 185-7, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11447443

ABSTRACT

Paraneoplastic limbic encephalitis is a rare clinical entity, associated most often with the oat cell carcinoma of the lung. Clinically, it presents with affective changes in personality, memory loss, confusional state, hallucinations, and seizures; with dementia being the common feature as the disorder progresses. Response to treatment is disappointingly poor.


Subject(s)
Carcinoma, Bronchogenic/etiology , Limbic Encephalitis/complications , Lung Neoplasms/etiology , Paraneoplastic Syndromes/complications , Carcinoma, Bronchogenic/diagnosis , Fatal Outcome , Humans , Limbic Encephalitis/diagnosis , Limbic Encephalitis/psychology , Lung Neoplasms/diagnosis , Magnetic Resonance Imaging , Male , Memory Disorders/etiology , Middle Aged , Paraneoplastic Syndromes/diagnosis , Paraneoplastic Syndromes/psychology , Personality , Radiography, Thoracic
11.
ANZ J Surg ; 71(7): 423-7, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11450919

ABSTRACT

BACKGROUND: In a prospective study of a patient population of 1,340 with biliary calculus disease, that ran from January 1993 to December 1997, 34 patients (2.53%) were identified as having Mirizzi syndrome. Eight patients were found to have type I (A and B) and 26 patients were found to have type II Mirizzi syndrome. A history of recurrent biliary colic and jaundice was present in the majority of patients. METHODS: Ultrasonography was helpful in five patients and endoscopic retrograde cholangiopancreatography was helpful in 17 patients in the diagnosis of this condition. Because the amount of gall bladder tissue used in choledochoplasty is not yet standardized, a new policy regarding choledochoplasty was adopted. In type IA, retrograde cholecystectomy with simple closure of cystic duct was carried out. In type IB, retrograde cholecystectomy and choledochoplasty with 5 mm cuff of the gall bladder was carried out. In type II lesions the procedure depended on the size of fistula. Patients with fistula sizes of less than one-third of the common bile duct diameter underwent choledochoplasty with 5 mm cuff of the gall bladder, and patients with fistula sizes between one-third and two-thirds of the diameter of the common bile duct underwent choledochoplasty with 10 mm cuff of the gall bladder. Patients with fistula sizes of more than two-thirds of the common bile duct diameter underwent Roux-en-Y hepaticojejunostomy. RESULTS: There was no operative mortality and the complication rate was 17.64%. CONCLUSION: Although, out of 26 choledochoplasties, we encountered only one (3.84%) stump stone in a maximum follow-up period of 59 months, further long-term follow-up studies are required to prove the efficacy of the procedure.


Subject(s)
Cholelithiasis/complications , Common Bile Duct Diseases/surgery , Anastomosis, Surgical , Biliary Fistula/surgery , Cholecystectomy , Common Bile Duct/surgery , Common Bile Duct Diseases/etiology , Female , Humans , Male , Middle Aged , Postoperative Complications/epidemiology , Prospective Studies , Retrospective Studies , Syndrome
12.
J Biol Chem ; 276(32): 29695-701, 2001 Aug 10.
Article in English | MEDLINE | ID: mdl-11340074

ABSTRACT

Turnover of the p53 tumor suppressor protein is mediated by Mdm2 through the ubiquitin proteolysis pathway. p300, a co-activator for p53, also participates in this process by complexing with Mdm2. We now report that the mutant Mdm2, defective in p53 binding, does not promote p53 ubiquitination and degradation in vivo or inhibit p53 transcriptional activation. By contrast, the mutant Mdm2, defective in p300 binding, still retains its activity to promote p53 ubiquitination and to inhibit p53 transcriptional activation but fails in promoting p53 degradation. We also show that both wild-type Mdm2 and the mutant Mdm2, defective in p300 binding, can promote the ubiquitination of cancer-derived p53 mutants, but only wild-type Mdm2 can cause their degradation. Furthermore, adenoviral oncoprotein, 12S.E.1A, but not its deletion mutant that lacks p300 binding, was shown to decrease in vivo ubiquitination of mutant p53. Taken together, these results provide genetic evidence that p300 plays a pivotal role in the regulation of Mdm2-mediated p53 turnover by integrating the cellular ubiquitination and proteolytic processes.


Subject(s)
Mutation , Nuclear Proteins/metabolism , Proto-Oncogene Proteins/genetics , Trans-Activators/metabolism , Tumor Suppressor Protein p53/metabolism , Ubiquitins/metabolism , Adenovirus E1A Proteins/genetics , Adenovirus E1A Proteins/metabolism , Blotting, Western , Cells, Cultured , Fibroblasts/metabolism , Gene Deletion , Genes, Reporter , Humans , Immunoblotting , Models, Biological , Protein Binding , Proto-Oncogene Proteins c-mdm2 , Transcription, Genetic , Transcriptional Activation , Transfection
13.
J Biol Chem ; 276(31): 29299-306, 2001 Aug 03.
Article in English | MEDLINE | ID: mdl-11375995

ABSTRACT

Lung Krüppel-like factor (LKLF/Krüppel-like factor 2), a member of the Krüppel-like factor family of transcription factors, is expressed predominantly in the lungs, with low levels of expression in other organs such as heart, spleen, skeletal muscle, and testis. LKLF is essential during pulmonary development and single-positive T-cell development and is indispensable during mouse embryogenesis. In this study, we performed a series of experiments to define the activation domain of LKLF as a means to further advance the understanding of the molecular mechanisms underlying transcriptional regulation by this transcription factor. Using deletion analysis, it is shown that LKLF contains a transcriptional activation domain as well as a strong autoinhibitory subdomain. The inhibitory subdomain is able to independently suppress transcriptional activation of other strong activators such as viral protein 16, VP16. This occurs either when the inhibitory domain is fused directly to VP16 or when the inhibitory domain is independently bound to DNA by GAL4 DNA-binding domain independent of the VP16 activator. Overexpression of the LKLF autoinhibitory domain alone potentiates transactivation by wild type LKLF, suggesting that the inhibitory domain binds a cofactor that prevents LKLF from transactivating. A yeast-two hybrid screen identified WWP1, an E3 ubiquitin ligase that binds specifically to the LKLF inhibitory domain but not to other transcription factors. In mammalian cells, WWP1 functions as a cofactor by binding LKLF and suppressing transactivation. These data demonstrate that LKLF contains multiple domains that either potentiate or inhibit the ability of this factor to function as an activator of transcription; moreover, regulation of LKLF transactivation is attenuated by an E3 ubiquitin ligase, WWP1.


Subject(s)
Caenorhabditis elegans Proteins , Ligases/chemistry , Ligases/metabolism , Lung/metabolism , Trans-Activators/chemistry , Trans-Activators/metabolism , Transcriptional Activation , Ubiquitin-Protein Ligases , Animals , Base Sequence , Binding Sites , COS Cells , Chloramphenicol O-Acetyltransferase/genetics , Chlorocebus aethiops , Cloning, Molecular , DNA Primers , Embryonic and Fetal Development , Gene Expression Regulation , Genes, Reporter , Kruppel-Like Transcription Factors , Lung Neoplasms , Male , Mice , Organ Specificity , Polymerase Chain Reaction , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/metabolism , Saccharomyces cerevisiae/genetics , T-Lymphocytes/physiology , Trans-Activators/genetics , Transcription, Genetic , Transfection , Tumor Cells, Cultured , Ubiquitins/chemistry , Ubiquitins/metabolism , Zinc Fingers
14.
Cancer Res ; 61(1): 64-70, 2001 Jan 01.
Article in English | MEDLINE | ID: mdl-11196199

ABSTRACT

The tumor suppressor protein p53 regulates various cellular responses to DNA damage and plays a significant role in DNA repair. The nuclear p300/cyclic AMP-responsive element binding (CREB)-binding protein (CBP) proteins act as coactivators in supporting the transcription function of p53. We examined the role of the human homologue of yeast Rad23 protein A (hHR23A), one of the two human homologues of the Saccharomyces cerevisiae nucleotide excision repair gene product Rad23, in the p300/CBP-associated regulation of p53 activity. Overexpression of wild-type hHR23A inhibits the p53 transcriptional activity and results in a decreased steady-state protein level of cellular p53. The inhibitory effect of hHR23A can be overcome by the concomitant expression of p300, CBP, and p300 segments harboring C/H1 domain and neutralized by the coexpression of HIV accessory protein Vpr, which binds COOH terminus of hHR23A/B. Additionally, hHR23A was shown to interact in vitro and in vivo with p300 segments harboring C/H1 domain. These studies provide evidence for the involvement of hHR23A in the regulation of p53 activity through p300/CBP. Although the precise direct role of hHR23 proteins in regulation of p53 and DNA repair remains to be elucidated, our data suggest that the interaction between hHR23A and p300/CBP has important implications in cross-talk between the p53 pathway and DNA repair.


Subject(s)
Cyclic AMP Response Element-Binding Protein/physiology , DNA-Binding Proteins/physiology , Nuclear Proteins/physiology , Trans-Activators/physiology , Transcription, Genetic/physiology , Tumor Suppressor Protein p53/physiology , Animals , Cyclic AMP Response Element-Binding Protein/biosynthesis , Cyclic AMP Response Element-Binding Protein/metabolism , Cyclin-Dependent Kinase Inhibitor p21 , Cyclins/biosynthesis , DNA Repair Enzymes , DNA-Binding Proteins/biosynthesis , DNA-Binding Proteins/metabolism , Down-Regulation/physiology , E1A-Associated p300 Protein , Gene Expression Regulation/physiology , Humans , Mice , Nuclear Proteins/biosynthesis , Nuclear Proteins/metabolism , Protein Binding , Protein Structure, Tertiary , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins/physiology , Proto-Oncogene Proteins c-mdm2 , Trans-Activators/biosynthesis , Trans-Activators/metabolism , Transcriptional Activation/physiology , Tumor Suppressor Protein p53/antagonists & inhibitors , Tumor Suppressor Protein p53/metabolism
15.
Article in English | MEDLINE | ID: mdl-18244829

ABSTRACT

This paper describes a new algorithm for obtaining rules automatically from training examples. The algorithm is applicable to examples involving both objects: with discrete and continuous-valued attributes. The paper explains a new quantization procedure fur continuous-valued attributes and shows how appropriate ranges of values of various attributes are obtained. The algorithm uses a decision-tree-based approach for obtaining rules, but unlike other tree-based algorithms such as ID3, it allows more than one attribute at a node which greatly improves its performance. The ability of the algorithm to obtain a measure of partial match further enhances its generalization characteristic. The algorithm produces the same rules irrespective of the order of presentation of training examples. The algorithm has been demonstrated on classification problems. The results have compared favorably with those obtained by existing inductive learning algorithms.

16.
Mol Carcinog ; 28(4): 215-24, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10972991

ABSTRACT

The increase in the p53 activity in response to DNA damage is thought to be one of the important mechanisms by which p53 contributes to transcriptional activation of p21(wafl), mdm2, and other downstream regulatory genes. To investigate the p53 response to ultraviolet (UV) type of DNA damage, p53 protein level, its transcriptional activity and in vivo ubiquitination were compared in repair-proficient normal human fibroblasts (NHFs) and repair-deficient xeroderma pigmentosum (XP) group A and group C (XP-C) fibroblasts subsequent to irradiation with UV light. Accumulation of p53 protein level was observed with increasing UV doses in all the cell lines; however, discordance between p53 and p21(waf1) and mdm2 levels was observed in NHF and XP-A cells. Induction of p21(waf1) and mdm2 was inhibited by UV irradiation, requiring higher doses in NHF and lower doses in XP-A cells. However, inhibition of p21(waf1) and mdm2 induction was not observed in XP-C cells. Ubiquitin-p53 conjugates could be detected in irradiated or unirradiated NHF and XP-A cells but not in XP-C cells irradiated with 30 and 50 J/m(2) UV light. Using a p53 reporter assay, p53 transcriptional activities were found to be induced by 10 J/m(2) UV exposure and dramatically inhibited with increasing UV doses in NHF cells. Compared with repair-proficient NHF cells, UV inhibition of p53 transcriptional activity was relatively more sensitive in XP-A cells but resistant in XP-C cells. These results indicate that DNA damage by UV, in addition to inducing p53, acts as a trigger for inhibition of p53 transcriptional activity. Overall, recognition of DNA damage links both p53 induction and p53 degradation to DNA repair mechanisms.


Subject(s)
DNA Damage , DNA Repair , Genes, p53/radiation effects , Transcription, Genetic/radiation effects , Tumor Suppressor Protein p53/metabolism , Ultraviolet Rays , Cell Line , Fibroblasts , Genes, Reporter , Humans , Luciferases/genetics , Transfection , Tumor Suppressor Protein p53/genetics , Ubiquitins/metabolism , Xeroderma Pigmentosum/genetics
17.
J Bacteriol ; 182(16): 4545-56, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10913088

ABSTRACT

In this study, we have cloned the ankB gene, encoding an ankyrin-like protein in Pseudomonas aeruginosa. The ankB gene is composed of 549 bp encoding a protein of 183 amino acids that possesses four 33-amino-acid ankyrin repeats that are a hallmark of erythrocyte and brain ankyrins. The location of ankB is 57 bp downstream of katB, encoding a hydrogen peroxide-inducible catalase, KatB. Monomeric AnkB is a 19.4-kDa protein with a pI of 5.5 that possesses 22 primarily hydrophobic amino acids at residues 3 to 25, predicting an inner-membrane-spanning motif with the N terminus in the cytoplasm and the C terminus in the periplasm. Such an orientation in the cytoplasmic membrane and, ultimately, periplasmic space was confirmed using AnkB-BlaM and AnkB-PhoA protein fusions. Circular dichroism analysis of recombinant AnkB minus its signal peptide revealed a secondary structure that is approximately 65% alpha-helical. RNase protection and KatB- and AnkB-LacZ translational fusion analyses indicated that katB and ankB are part of a small operon whose transcription is induced dramatically by H(2)O(2), and controlled by the global transactivator OxyR. Interestingly, unlike the spherical nature of ankyrin-deficient erythrocytes, the cellular morphology of an ankB mutant was identical to that of wild-type bacteria, yet the mutant produced more membrane vesicles. The mutant also exhibited a fourfold reduction in KatB activity and increased sensitivity to H(2)O(2), phenotypes that could be complemented in trans by a plasmid constitutively expressing ankB. Our results suggest that AnkB may form an antioxidant scaffolding with KatB in the periplasm at the cytoplasmic membrane, thus providing a protective lattice work for optimal H(2)O(2) detoxification.


Subject(s)
Ankyrins/metabolism , Catalase/metabolism , Hydrogen Peroxide/pharmacology , Periplasmic Proteins , Pseudomonas aeruginosa/metabolism , Amino Acid Sequence , Ankyrin Repeat , Ankyrins/chemistry , Ankyrins/genetics , Catalase/genetics , Cell Membrane/metabolism , Cell Membrane/ultrastructure , Chromosome Mapping , Cloning, Molecular , Molecular Sequence Data , Plasmids , Protein Conformation , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/genetics , Pseudomonas aeruginosa/ultrastructure , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/metabolism , Sequence Alignment , Sequence Homology, Amino Acid
18.
Cancer Res ; 60(8): 2273-80, 2000 Apr 15.
Article in English | MEDLINE | ID: mdl-10786695

ABSTRACT

DNA damage from exposure to environmental chemical carcinogens and failure of repair systems to eliminate these lesions from the genome are considered as the crucial initial steps in the development of various human malignancies. Many cellular proteins are known to play vital roles to overcome the effects of DNA damage. Among such proteins, p53 is known to respond to DNA damage by accumulating in the nucleus and inhibiting cell cycle progression to facilitate DNA repair and the maintenance of genomic stability. In this study, we have investigated the role of p53 protein in modulating nucleotide excision repair of anti-benzo-(a)pyrene-diol-epoxide (BPDE)-DNA adducts and related effects using human fibroblasts with normal (p53-WT) and altered p53 protein (p53Mut and p53-Null). Interestingly, irrespective of the presence or absence of p53, the anti-BPDE dose-dependent p21 protein induction response was qualitatively comparable in all of the three cell lines. However, cells with defective p53 function were deficient for the removal of anti-BPDE-DNA adducts from the overall genome compared to cells with wild-type p53 activity. Strand-specific repair analysis within the individual strands of the p53 gene revealed decreased repair of adducts from the nontranscribed strand in p53-Mut and p53-Null cells. However, the repair of the transcribed strand appeared to be identical in all of the three cell lines. Furthermore, p53-Mut and p53-Null cells were more sensitive than p53-WT cells and displayed increased levels of anti-BPDE-induced apoptosis. Thus, wild-type p53 is required for the efficient global genomic repair of anti-BPDE-induced DNA adducts from the overall genome, but not for transcription-coupled repair of actively transcribed genes. These findings indicate that inefficient DNA repair of potentially cytotoxic and mutagenic lesions from the nontranscribed strand due to the loss of p53, but not the loss of p21, function might be responsible for enhanced cytotoxicity and apoptosis in human cells upon DNA damage.


Subject(s)
Benzopyrenes/toxicity , Carcinogens/toxicity , DNA Damage/drug effects , DNA Repair/drug effects , Genome, Human , Tumor Suppressor Protein p53/metabolism , 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide/metabolism , Apoptosis/drug effects , Benzopyrenes/metabolism , Carcinogens/metabolism , Cell Line , Cell Survival/drug effects , Cyclin-Dependent Kinase Inhibitor p21 , Cyclins/metabolism , DNA Adducts/metabolism , DNA Damage/genetics , DNA Repair/genetics , DNA, Single-Stranded/drug effects , DNA, Single-Stranded/genetics , Dose-Response Relationship, Drug , Fibroblasts/cytology , Fibroblasts/drug effects , Fibroblasts/metabolism , Genes, p53/genetics , Humans , Mutation/genetics , Transcription, Genetic/drug effects , Transcription, Genetic/genetics , Tumor Suppressor Protein p53/genetics , Up-Regulation/drug effects
19.
Mutat Res ; 459(2): 135-45, 2000 Mar 20.
Article in English | MEDLINE | ID: mdl-10725664

ABSTRACT

Nucleotide excision repair (NER), the most versatile and ubiquitous mechanism for DNA repair, operates to remove many types of DNA base lesions. We have studied the role of p53 function in modulating the repair of DNA damage following UV irradiation in normal and p53-compromised human mammary epithelial cells (HMEC). The effect of UV-induced DNA damage on cellular cytotoxicity and apoptosis was determined in conjunction with global, gene- and strand-specific repair. Cytotoxicity studies, using clonogenic survival and MTT assays, showed that HPV-16 E6-expressing HMEC were more UV sensitive than p53-WT cell lines. High apoptotic index obtained with p53-compromised cells was in conformity to both the low clonogenic survival and the low cellular viability. No discernible differences in the formation of initial UV-induced cyclobutane pyrimidine dimers (CPD) were observed in the cell lines of varying p53 functional status. However, the extent and the rate of damage removal from genome overall were highest for p53-WT cells. Further examination of strand-specific repair in the p53 gene revealed that the removal of CPD in the non-transcribed strand (NTS) was slower in p53-compromised cells compared to the normal p53-WT cell lines. These results suggest that loss of p53 function, in the absence of other genetic alterations, decreased both overall amount of CPD repaired and their removal rate from the genome. Additionally, normal function of p53 is required for the repair of the NTS, but not of the transcribed strand (TS) in genomic DNA in human epithelial cells. Thus, failure of quantitative removal of CPD by global genomic repair (GGR), due to loss of p53 function, causes the enhanced UV sensitivity and increased damage-induced apoptosis via a p53-independent pathway. Nevertheless, recovery of cells from UV damage requires normal p53 function and efficient GGR.


Subject(s)
DNA Repair , Oncogene Proteins, Viral/metabolism , Papillomaviridae/metabolism , Pyrimidine Dimers/metabolism , Repressor Proteins , Tumor Suppressor Protein p53/metabolism , Apoptosis/radiation effects , Breast/cytology , Breast/radiation effects , Cells, Cultured , Epithelial Cells/cytology , Humans , Transcription, Genetic , Ultraviolet Rays
20.
JK Pract ; 7(1): 1-3, 2000.
Article in English | MEDLINE | ID: mdl-12295955

ABSTRACT

PIP: Neural tube defect (NTD) is a group of congenital anomalies, which include anencephaly, encephalocele, iniencephaly, meningocele, myelomeningocele, myeloschisis, lipomeningocele, and rashischisis. Congenital malformations of the central nervous system constitute more than half of all congenital malformations with an incidence of 1-2/1000 births. The condition is thought to arise from multifactorial etiology with a distinct genetic predisposition. This paper discusses the pathogenesis of NTD and explores the use of folic acid for the prevention of this serious congenital malformation. Two studies, which have shown a significant protective effect of folic acid use on NTD prevention in high-risk mothers, are cited. In considering the effectiveness of folic acid supplementation on NTD prevention, obstetricians, pediatricians, neonatologists, and family doctors are called to initiate a collective effort to increase awareness among women in the childbearing age on the need of daily multivitamin intake with folic acid prior to pregnancy.^ieng


Subject(s)
Central Nervous System , Congenital Abnormalities , Developing Countries , Vitamins , Biology , Congenital, Hereditary, and Neonatal Diseases and Abnormalities , Disease , Micronutrients , Physiology
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