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1.
J Physiol Pharmacol ; 75(2): 173-183, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38736264

ABSTRACT

Quercetin is widely distributed in plants as a flavonol compound with multiple biological activities. It has been found that quercetin can regulate bone homeostasis through multiple pathways and targets. This study investigated the role and specific molecular mechanisms of quercetin in regulating osteoblast viability, proliferation, migration and osteogenic differentiation. A mouse model of traumatic fracture was established and then 100 mg/kg quercetin corn oil suspension was gavaged at the same time every day for 28 days. miR-6089 and E2F transcription factor 2 (E2F2) expression levels in mice were measured. Fracture healing in mice was observed. MC3T3-E1 cells were transfected with plasmids targeting miR-6089 and E2F2, and cell viability, proliferation, migration, apoptosis, and osteogenic differentiation were determined. The targeting relationship between miR-6089 and E2F2 was verified. In vivo experiments showed that quercetin significantly increased osteocalcin (OCN) expression (P<0.05) and promoted fracture healing in traumatic fracture (TF) mice. miR-6089 expression was down-regulated (P<0.05) and E2F2 expression was up-regulated (P<0.05) in TF mice. Quercetin promoted miR-6089 expression and inhibited E2F2 expression (both P<0.05). In vitro results showed that quercetin promoted miR-6089 expression and inhibited E2F2 expression in a dose-dependent manner (both P<0.05). Quercetin dose-dependently promoted MC3T3-E1 cell viability, proliferation, migration, and osteogenic differentiation, and inhibited MC3T3-E1 cell apoptosis (all P<0.05). Up-regulating miR-6089 further promoted MC3T3-E1 cell viability, proliferation, migration and osteogenic differentiation, and inhibited MC3T3-E1 cell apoptosis (all P<0.05). miR-6089 targeted and regulated E2F2 expression. Up-regulating E2F2 attenuated the promoting effect of up-regulated miR-6089 on MC3T3-E1 cell viability, proliferation, migration, osteogenic differentiation, and inhibition of apoptosis (all P<0.05). We conclude that quercetin enhances osteoblast viability, proliferation, migration, and osteogenic differentiation by modulating the miR-6089/E2F2 axis, thereby promoting fracture healing.


Subject(s)
E2F2 Transcription Factor , Fracture Healing , MicroRNAs , Osteoblasts , Osteogenesis , Quercetin , Animals , Male , Mice , Apoptosis/drug effects , Cell Differentiation/drug effects , Cell Line , Cell Movement/drug effects , Cell Proliferation/drug effects , Cell Survival/drug effects , E2F2 Transcription Factor/metabolism , E2F2 Transcription Factor/genetics , Fracture Healing/drug effects , MicroRNAs/genetics , MicroRNAs/metabolism , Osteoblasts/drug effects , Osteoblasts/metabolism , Osteogenesis/drug effects , Quercetin/pharmacology
2.
J Vet Intern Med ; 27(1): 126-33, 2013.
Article in English | MEDLINE | ID: mdl-23205923

ABSTRACT

BACKGROUND: Cisplatin combined with a nonselective cyclooxygenase (cox) inhibitor has potent antitumor activity against transitional cell carcinoma (TCC) in dogs, but this treatment is limited by renal toxicosis. Cox-2 is expressed in TCC, but only in limited sites within the kidney. A cox-2 inhibitor could enhance the antitumor activity of cisplatin with potentially fewer adverse effects on the kidney. HYPOTHESIS: Cisplatin/cox-2 inhibitor treatment will have greater antitumor activity but no more renal toxicosis than cisplatin alone in dogs with TCC. ANIMALS: Forty-four dogs with naturally occurring urinary bladder TCC. METHODS: Dogs were randomized to receive cisplatin (60 mg/m(2) IV q21d), firocoxib (5 mg/kg PO q24h), or the combination. Tumor measurements were determined before and at 6-week intervals during treatment. Renal function was monitored by serum creatinine concentration, iohexol clearance, and urine specific gravity. Toxicoses were graded according to Veterinary Co-Operative Oncology Group (VCOG) criteria. RESULTS: The remission rate with cisplatin/firocoxib (57%) was significantly (P = .021) higher than that with cisplatin alone (13%). Renal and gastrointestinal toxicoses were common in dogs receiving cisplatin, but there were no significant differences between dogs receiving cisplatin or cisplatin/firocoxib. Firocoxib alone induced partial remission or stable disease in 20 and 33% of dogs, respectively. CONCLUSIONS: Firocoxib significantly enhanced the antitumor activity of cisplatin resulting in partial remission in more than half of the cases. The toxicoses inherent to cisplatin, however, were noted in dogs receiving this combination. Firocoxib had antitumor effects as a single agent and can be considered a palliative treatment for dogs with TCC.


Subject(s)
4-Butyrolactone/analogs & derivatives , Antineoplastic Agents/therapeutic use , Carcinoma, Transitional Cell/veterinary , Cisplatin/therapeutic use , Dog Diseases/drug therapy , Sulfones/therapeutic use , Urinary Bladder Neoplasms/veterinary , 4-Butyrolactone/administration & dosage , 4-Butyrolactone/adverse effects , 4-Butyrolactone/therapeutic use , Animals , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/adverse effects , Carcinoma, Transitional Cell/drug therapy , Cisplatin/administration & dosage , Cisplatin/adverse effects , Dog Diseases/chemically induced , Dogs , Drug Therapy, Combination , Female , Gastrointestinal Diseases/chemically induced , Gastrointestinal Diseases/veterinary , Male , Quality of Life , Sulfones/administration & dosage , Sulfones/adverse effects , Urinary Bladder Neoplasms/drug therapy
3.
Ir Med J ; 105(8): 271-4, 2012 Sep.
Article in English | MEDLINE | ID: mdl-23155914

ABSTRACT

Studies suggest older adults attending emergency departments(ED) benefit from specialist geriatric medicine evaluation. Findings from a pilot ED Geriatric Medicine(GM) liaison service in our 480-bed university hospital are presented. This is not a randomized controlled trial. Service comprised consultant geriatrician and senior trainee-led sessions during daytime working hours. Senior ED personnel selected appropriate patients. GM service also took over ED medical admissions aged 80, 1 in 9 days from General Internal Medicine(GIM). 49% of 284 patients (83.5 +/- 6.8 years) referred, were discharged from ED with appropriate follow-up. Inpatient analysis comprised 51% admitted to GIM, GM and specialist services as per on-call rota and 268 patients taken over from GIM. Patients under GM had shorter length of stay (p < 0.001). The findings suggest specialty specific geriatric medicine management of the older adult presenting to ED can improve service and patient outcomes.


Subject(s)
Emergency Service, Hospital/organization & administration , Geriatrics , Patient Admission , Aged , Aged, 80 and over , Female , Geriatric Assessment , Humans , Internal Medicine , Male
4.
Biomed Opt Express ; 3(8): 1947-54, 2012 Aug 01.
Article in English | MEDLINE | ID: mdl-22876357

ABSTRACT

Transbronchial needle aspiration (TBNA) is a procedure routinely performed to diagnose peripheral pulmonary lesions. However, TBNA is associated with a low diagnostic yield due to inappropriate needle placement. We have developed a flexible transbronchial optical frequency domain imaging (TB-OFDI) catheter that functions as a "smart needle" to confirm the needle placement within the target lesion prior to biopsy. The TB-OFDI smart needle consists of a flexible and removable OFDI catheter (430 µm dia.) that operates within a standard 21-gauge TBNA needle. The OFDI imaging core is based on an angle polished ball lens design with a working distance of 160 µm from the catheter sheath and a spot size of 25 µm. To demonstrate the potential of the TB-OFDI smart needle for transbronchial imaging, an inflated excised swine lung was imaged through a standard bronchoscope. Cross-sectional and longitudinal OFDI results reveal the detailed network of alveoli in the lung parenchyma suggesting that the TB-OFDI smart needle may be a useful tool for guiding biopsy acquisition to increase the diagnostic yield.

5.
J Vet Intern Med ; 25(6): 1385-90, 2011.
Article in English | MEDLINE | ID: mdl-22092632

ABSTRACT

BACKGROUND: Transitional cell carcinoma (TCC) of the urinary bladder of dogs can be a difficult cancer to treat, and effective therapies are limited. Vinblastine has been used in humans with TCC and has potent anti-proliferative effects against canine TCC cells in vitro. OBJECTIVES: To determine the antitumor activity and toxicoses of vinblastine in dogs with urinary bladder TCC. ANIMALS: Animals selected were 28 privately owned dogs that presented to the Purdue University Veterinary Teaching Hospital (PUVTH) with measurable, histologically confirmed TCC. METHODS: Prospective clinical trial: The starting vinblastine dosage was 3.0 mg/m(2) i.v. every 2 weeks. Treatment continued until cancer progression or unacceptable toxicoses occurred. Complete evaluations (physical exam, complete blood count [CBC], serum biochemical profile, urinalysis, thoracic radiography, abdominal ultrasound [US]) were performed at 8-week intervals. Urinary tract US with bladder tumor mapping was performed monthly. Toxicoses were graded according to Veterinary Co-Operative Oncology Group (VCOG) criteria. RESULTS: Tumor responses included 10 (36%) partial remission, 14 (50%) stable disease, and 4 (14%) progressive disease. The median progression free interval was 122 days (range, 28-399 days). The median survival time was 147 days (range, 28-476 days) from 1st vinblastine treatment to death and 299 days (range, 43-921 days) from diagnosis to death. The majority of dogs (27 of 28) did not have clinically relevant adverse effects. Seventeen of 28 (61%) dogs required dosage reductions because of neutropenia. CONCLUSION AND CLINICAL IMPORTANCE: Vinblastine has antitumor activity against TCC in dogs and can be considered another treatment option for this cancer.


Subject(s)
Antineoplastic Agents, Phytogenic/therapeutic use , Carcinoma, Transitional Cell/veterinary , Dog Diseases/drug therapy , Urinary Bladder Neoplasms/veterinary , Vinblastine/therapeutic use , Animals , Carcinoma, Transitional Cell/drug therapy , Cell Line, Tumor , Dogs , Dose-Response Relationship, Drug , Female , Male , Urinary Bladder Neoplasms/drug therapy
6.
Ir J Med Sci ; 180(1): 41-5, 2011 Mar.
Article in English | MEDLINE | ID: mdl-20665122

ABSTRACT

BACKGROUND: Stroke can affect a person's ability to drive, an important means of transportation in the developed world. AIMS: To determine percentage of patients and factors associated with return to driving post-stroke in a service with emphasis on driver assessment. METHODS: Retrospective study of patients discharged from the Stroke Service of our 470-bed teaching hospital from 1998 to 2002. RESULTS: Of 72 drivers pre-stroke, 54% recalled a driving assessment and 68% returned to driving. Younger patients (58.6 ± 12.0 vs. 66.5 ± 10.5, p = 0.008) with lower Modified Rankin Score (median 1 vs. 2, p = 0.0001) and normal cognition (55 vs. 43%, p = 0.45) were more likely to resume driving. More patients who were assessed returned to driving than those who were not (74 vs. 61%, p = 0.31). CONCLUSIONS: A relatively high level of return to driving can be achieved post-stroke with a pro-active approach to driver assessment and rehabilitation. A structured assessment and referral programme should be offered where appropriate.


Subject(s)
Automobile Driving , Stroke Rehabilitation , Adult , Aged , Aged, 80 and over , Automobile Driving/statistics & numerical data , Female , Humans , Ireland , Male , Middle Aged , Retrospective Studies
7.
Opt Express ; 18(8): 7642-9, 2010 Apr 12.
Article in English | MEDLINE | ID: mdl-20588604

ABSTRACT

We report a novel fiber probe based Raman detection system on a microfluidic platform where a split Raman probe is directly embedded into a polydimethylsiloxane (PDMS) chip. In contrast to previous Raman detection schemes in microfluidics, probe based detection offers reduced background and portability. Compared to conventional backscattering probe designs, the split fiber probe we used in this system, results in a reduced size and offers flexibility to modify the collection geometry to minimize the background generated by the fibers. Also our microfluidic chip design enables us to obtain an alignment free system. As a proof of concept we demonstrate the sensitivity of the device for urea detection at relevant human physiological levels with a low acquisition time. The development of this system on a microfluidic platform means portable, lab on a chip devices for biological analyte detection and environmental sensing using Raman spectroscopy are now within reach.


Subject(s)
Microfluidics/instrumentation , Microfluidics/methods , Optical Fibers , Spectrum Analysis, Raman/instrumentation , Spectrum Analysis, Raman/methods , Ethanol/analysis , Limit of Detection , Rheology , Time Factors , Urea/analysis
8.
Case Rep Med ; 2010: 549258, 2010.
Article in English | MEDLINE | ID: mdl-21209814

ABSTRACT

WE DESCRIBE AN UNUSUAL COMPLICATION OF A COMMON DISEASE: stroke presenting in a man recently diagnosed with polymyalgia rheumatica. Initial inflammatory markers were misleading. We discuss pitfalls in diagnosis, and approach to management.

9.
Opt Express ; 17(4): 2375-84, 2009 Feb 16.
Article in English | MEDLINE | ID: mdl-19219141

ABSTRACT

Common-path optical coherence tomography (CPOCT) is known to reduce group velocity dispersion and polarization mismatch between the reference and the sample arm as both arms share the same physical path. Existing implementations of CPOCT typically require one to incorporate an additional cover glass within the beam path of the sample arm to provide a reference signal. In this paper, we aim to further reduce this step by directly making use of the back-reflected signal, arising from a conical lens-tip fiber, as a reference signal. The conical lens, which is directly manufactured onto the optical fiber tip via a simple selective-chemical etching process, fulfils two functions acting as both the imaging lens and the self-aligning reference plane. We use a Fourier-domain OCT system to demonstrate the feasibility of this technique upon biological tissue. An in-fiber CPOCT technique may prove potentially useful in endoscopic OCT imaging.


Subject(s)
Endoscopy , Fiber Optic Technology/instrumentation , Image Enhancement/instrumentation , Tomography, Optical Coherence/instrumentation , Transducers , Computer-Aided Design , Equipment Design , Equipment Failure Analysis , Reproducibility of Results , Sensitivity and Specificity
10.
Neurology ; 70(20): 1883-90, 2008 May 13.
Article in English | MEDLINE | ID: mdl-18474843

ABSTRACT

OBJECTIVE: To document neurologic, oncologic, and serologic associations of patients in whom voltage-gated potassium channel (VGKC) autoantibodies were detected in the course of serologic evaluation for neuronal, glial, and muscle autoantibodies. METHODS: Indirect immunofluorescence screening of sera from 130,000 patients performed on a service basis for markers of paraneoplastic neurologic autoimmunity identified 80 patients whose IgG bound to the synapse-rich molecular layer of mouse cerebellar cortex in a pattern consistent with VGKC immunoreactivity. Antibody specificity was confirmed in all cases by immunoprecipitation of detergent-solubilized brain synaptic proteins complexed with (125)I-alpha-dendrotoxin. RESULTS: Clinical information was available for 72 patients: 51% women, median age at symptom onset 65 years, and median follow-up period 14 months. Neurologic manifestations were acute to subacute in onset in 71% and multifocal in 46%; 71% had cognitive impairment, 58% seizures, 33% dysautonomia, 29% myoclonus, 26% dyssomnia, 25% peripheral nerve dysfunction, 21% extrapyramidal dysfunction, and 19% brainstem/cranial nerve dysfunction. Creutzfeldt-Jakob disease was a common misdiagnosis (14%). Neoplasms encountered (confirmed histologically in 33%) included 18 carcinomas, 5 adenomas, 1 thymoma, and 3 hematologic malignancies. Hyponatremia was documented in 36%, other organ-specific autoantibodies in 49%, and a co-existing autoimmune disorder in 33% (including thyroiditis 21%, type 1 diabetes mellitus 11%). Benefit was reported for 34 of 38 patients (89%) receiving immunotherapy and was marked in 50%. CONCLUSIONS: The spectrum of neurologic manifestations and neoplasms associated with voltage-gated potassium channel (VGKC) autoimmunity is broader than previously recognized. Evaluation for VGKC antibodies is recommended in the comprehensive autoimmune serologic testing of subacute idiopathic neurologic disorders.


Subject(s)
Autoantibodies/blood , Paraneoplastic Syndromes/immunology , Peripheral Nervous System Diseases/immunology , Shaker Superfamily of Potassium Channels/immunology , Adenoma/complications , Adolescent , Adult , Aged , Aged, 80 and over , Autonomic Nervous System Diseases/etiology , Autonomic Nervous System Diseases/immunology , Basal Ganglia Diseases/etiology , Basal Ganglia Diseases/immunology , Child , Cranial Nerve Diseases/etiology , Cranial Nerve Diseases/immunology , Female , Fluorescent Antibody Technique, Indirect , Hematologic Neoplasms/complications , Humans , Kv1.1 Potassium Channel/immunology , Kv1.2 Potassium Channel/immunology , Kv1.6 Potassium Channel , Male , Middle Aged , Myoclonus/etiology , Myoclonus/immunology , Paraneoplastic Syndromes/complications , Peripheral Nervous System Diseases/etiology , Thymoma/complications , Thymus Neoplasms/complications
11.
Ir J Med Sci ; 176(2): 75-9, 2007.
Article in English | MEDLINE | ID: mdl-17447105

ABSTRACT

BACKGROUND: In 2002, a survey of stroke management was conducted in our institution benchmarked against the UK National Stroke Audit 2002. The conclusion was that management of stroke patients lacked organised and specialised care. The introduction of a stroke care pathway was recommended. AIMS: This audit assessed the clinical impact of implementation of a stroke care pathway by the general medical teams in an acute teaching hospital. METHODS: A random sample of 48/131 patients were surveyed in 2002 compared to 55 consecutive patients admitted with stroke in 2005. RESULTS: Despite introduction of a stroke care pathway, marked deficits persisted in acute management including delays in brain imaging and aspirin administration, assessment of acute parameters and interdisciplinary care. CONCLUSIONS: Optimal care of stroke patients cannot be achieved by introducing a stroke care pathway alone. We recommend the urgent establishment of a stroke unit with a specialist consultant-led multidisciplinary stroke team.


Subject(s)
Critical Pathways , Hospitals, Teaching/standards , Medical Audit , Patient Care Team/standards , Stroke/therapy , Aged , Benchmarking , Female , Humans , Ireland , Male , Stroke Rehabilitation
12.
Ir J Med Sci ; 174(3): 28-31, 2005.
Article in English | MEDLINE | ID: mdl-16285335

ABSTRACT

BACKGROUND: Patient falls are a common complication of hospitalisation. Use of restraints in patients who are perceived to be at risk for falling may lead to injury and even death. AIMS: To determine the frequency of falls and fall-related injuries and the contribution of restraints in a hospital population. METHODS: We analysed incident reports of falls for a single year from a large teaching hospital. Results The fall rate per 10,000 patient days was 13.2 (95%CI 11.6-14.8). Fall rate increased dramatically with increased age. Eighty-two (30.7%) falls resulted in injury, of which 6 (7.3%) were serious. Injuries occurred in 71/247 (29%) unrestrained falls and in 11/20 (55%) falls in patients who were restrained. Injuries were more severe in falls with restraints in place (p < 0.0001). CONCLUSIONS: Restraint use is associated with increased severity of injury in hospital patients who fall.


Subject(s)
Accidental Falls/statistics & numerical data , Hospitals, Teaching/statistics & numerical data , Restraint, Physical/statistics & numerical data , Accidental Falls/prevention & control , Acute Disease , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , Beds , Equipment Design , Female , Humans , Incidence , Injury Severity Score , Male , Middle Aged , Restraint, Physical/adverse effects , Restraint, Physical/instrumentation , Retrospective Studies , Risk Assessment , Risk Factors
13.
Ir J Med Sci ; 174(1): 49-54, 2005.
Article in English | MEDLINE | ID: mdl-15868890

ABSTRACT

BACKGROUND: When worn external Hip Protectors (EHP) reduce hip fracture but poor compliance results in reduced efficacy. AIMS: We determined the compliance with EHP therapy among a group of elderly people attending a day hospital. METHODS: Forty-five patients or their care-givers were interviewed a mean (sd) 334 (150) days after they had been given EHP. RESULTS: There were 12 men and 33 women with mean age of 80 (7) years. Only ten (22%) were still wearing EHP properly. Those who were compliant were given their EHP more recently than those who were not (277 (118) days vs 403 (159), p = 0.0062) and were more likely to feel safer when wearing them (p = 00.017, chi2= 5.68). Reasons for non-compliance included exclusive outdoor wear, discomfort and inconvenience. CONCLUSIONS: Hip protector compliance was poor in this small study of elderly individuals attending a day hospital. Better patient education may improve compliance though this needs to be determined.


Subject(s)
Day Care, Medical , Hip Fractures/prevention & control , Patient Compliance/statistics & numerical data , Protective Devices/statistics & numerical data , Activities of Daily Living , Aged , Aged, 80 and over , Day Care, Medical/statistics & numerical data , Female , Hospitals/statistics & numerical data , Humans , Interviews as Topic , Male , Patient Compliance/psychology , Prospective Studies , Prosthesis Design , Time Factors
15.
J Clin Neurosci ; 8(5): 404-6, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11535004

ABSTRACT

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leucoencephalopathy (CADASIL) is a recently described cause of stroke or stroke-like episodes. It is caused by mutations in the Notch3 gene on chromosome 19p. We sought to demonstrate mutations of the Notch3 gene in Australian patients suspected of having CADASIL. Patients from several families were referred to the study. A diagnosis was determined clinically and by neuroimaging. Those suspected of having CADASIL had sequencing of exons 3 and 4 of the Notch3 gene. Eight patients, two of whom were siblings, were suspected of having CADASIL. Five patients (including the siblings) had mutations. Because of strong clustering of Notch3 mutations in CADASIL, this has potential as a reliable test for the disease in Australian patients.


Subject(s)
Dementia, Multi-Infarct/genetics , Proto-Oncogene Proteins/genetics , Receptors, Cell Surface , Aged , Australia , Dementia, Multi-Infarct/diagnostic imaging , Exons , Genotype , Humans , Magnetic Resonance Imaging , Middle Aged , Point Mutation , Radiography , Receptor, Notch3 , Receptors, Notch
16.
J Biol Chem ; 276(47): 44193-202, 2001 Nov 23.
Article in English | MEDLINE | ID: mdl-11559703

ABSTRACT

In Caenorhabditis elegans, fem-1, fem-2, and fem-3 play pivotal roles in sex determination. Recently, a mammalian homologue of the C. elegans sex-determining protein FEM-1, F1Aalpha, has been described. Although there is little evidence to link F1Aalpha to sex determination, F1Aalpha and FEM-1 both promote apoptosis in mammalian cells. Here we report the identification and characterization of a human homologue of the C. elegans sex-determining protein FEM-2, hFEM-2. Similar to FEM-2, hFEM-2 exhibited PP2C phosphatase activity and associated with FEM-3. hFEM-2 shows striking similarity (79% amino acid identity) to rat Ca(2+)/calmodulin (CaM)-dependent protein kinase phosphatase (rCaMKPase). hFEM-2 and FEM-2, but not PP2Calpha, were demonstrated to dephosphorylate CaM kinase II efficiently in vitro, suggesting that hFEM-2 and FEM-2 are specific phosphatases for CaM kinase. Furthermore, hFEM-2 and FEM-2 associated with F1Aalpha and FEM-1 respectively. Overexpression of hFEM-2, FEM-2, or rCaMKPase all mediated apoptosis in mammalian cells. The catalytically active, but not the inactive, forms of hFEM-2 induced caspase-dependent apoptosis, which was blocked by Bcl-XL or a dominant negative mutant of caspase-9. Taken together, our data suggest that hFEM-2 and rCaMKPase are mammalian homologues of FEM-2 and they are evolutionarily conserved CaM kinase phosphatases that may have a role in apoptosis signaling.


Subject(s)
Apoptosis , Caenorhabditis elegans Proteins , Caenorhabditis elegans/metabolism , Calcium-Calmodulin-Dependent Protein Kinases/metabolism , Helminth Proteins/metabolism , Phosphoprotein Phosphatases , Amino Acid Sequence , Animals , Calcium-Calmodulin-Dependent Protein Kinase Type 2 , Cell Line , Helminth Proteins/chemistry , Humans , Mice , Molecular Sequence Data , Phosphorylation , Sequence Homology, Amino Acid
17.
J Biol Chem ; 276(4): 2802-7, 2001 Jan 26.
Article in English | MEDLINE | ID: mdl-11060313

ABSTRACT

A novel Bax-associating protein, named MAP-1 (Modulator of Apoptosis), has been identified in a yeast two-hybrid screen. MAP-1 contains a BH3-like (BH: Bcl-2 homology) motif and mediates caspase-dependent apoptosis in mammalian cells when overexpressed. MAP-1 homodimerizes and associates with the proapoptotic Bax and the prosurvival Bcl-2 and Bcl-X(L) of the Bcl-2 family in vitro and in vivo in mammalian cells. Mutagenesis analyses revealed that the BH3-like domain in MAP-1 is not required for its association with Bcl-X(L) but is required for association with Bax and for mediating apoptosis. Interestingly, in contrast to other Bax-associating proteins such as Bcl-X(L) and Bid, which require the BH3 and BH1 domains of Bax, respectively, for binding, the binding of MAP-1 to Bax appears to require all three BH domains (BH1, BH2, and BH3) of Bax, because point mutation of the critical amino acid in any one of these domains is sufficient to abolish its binding to MAP-1. These data suggest that MAP-1 mediates apoptosis through a mechanism that involves binding to Bax.


Subject(s)
Adaptor Proteins, Signal Transducing , Apoptosis , Carrier Proteins/metabolism , Proto-Oncogene Proteins c-bcl-2/metabolism , Proto-Oncogene Proteins/metabolism , Amino Acid Motifs , Amino Acid Sequence , Animals , Apoptosis Regulatory Proteins , Binding Sites , Carrier Proteins/genetics , Caspases/metabolism , Conserved Sequence , Dimerization , Humans , Mice , Molecular Sequence Data , Protein Binding , Protein Structure, Tertiary , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins c-bcl-2/genetics , Sequence Homology, Amino Acid , bcl-2-Associated X Protein
18.
J Biol Chem ; 275(24): 17925-8, 2000 Jun 16.
Article in English | MEDLINE | ID: mdl-10764728

ABSTRACT

Sex-specific elimination of cells by apoptosis plays a role in sex determination in Caenorhabditis elegans. Recently, a mammalian pro-apoptotic protein named F1Aalpha has been identified. F1Aalpha shares extensive homology throughout the entire protein with the C. elegans protein, FEM-1, which is essential for achieving all aspects of the male phenotype in the nematode. In this report, the role of FEM-1 in apoptosis was investigated. Overexpression of FEM-1 induces caspase-dependent apoptosis in mammalian cells. FEM-1 is cleaved in vitro by the C. elegans caspase, CED-3, generating an N-terminal cleavage product that corresponds to the minimal effector domain for apoptosis. Furthermore, CED-4 associates with FEM-1 in vitro and in vivo in mammalian cells and potentiates FEM-1-mediated apoptosis. Similarly, Apaf-1, the mammalian homologue of CED-4 was found to associate with F1Aalpha. These data suggest that FEM-1 and F1Aalpha may mediate apoptosis by communicating directly with the core machinery of apoptosis.


Subject(s)
Apoptosis , Caenorhabditis elegans Proteins , Caenorhabditis elegans/metabolism , Calcium-Binding Proteins/metabolism , Caspases , Cell Cycle Proteins/metabolism , Cysteine Endopeptidases/metabolism , Helminth Proteins/metabolism , Animals , Cell Line , Humans , Kinetics , Male , Protein Binding , Sequence Homology, Amino Acid
19.
J Biol Chem ; 274(34): 23687-90, 1999 Aug 20.
Article in English | MEDLINE | ID: mdl-10446124

ABSTRACT

Upon activation of the Fas apoptotic signaling pathway, Bid, a "BH3 domain-only" pro-apoptotic molecule, is cleaved by caspase-8 into a 6.5-kDa N-terminal and a 15-kDa BH3 domain-containing C-terminal fragment, referred to as t(n)-Bid and t(c)-Bid, respectively. t(c)-Bid is a more potent inducer of apoptosis than full-length Bid, suggesting that the N-terminal region of Bid has an inhibitory effect on its pro-apoptotic activity. Here, we report the identification of a novel BH3-like motif (amino acid residues 35-43) in t(n)-Bid. Although Bid does not homodimerize, t(n)-Bid is able to associate avidly with t(c)-Bid. Site-directed mutagenesis revealed that both the novel BH3-like and BH3 domains are necessary for direct binding between t(n)-Bid and t(c)-Bid. While full-length Bid does not associate with t(n)-Bid, substitution of Leu(35), a critical residue in mediating t(n)-Bid/t(c)-Bid interaction, with Ala in full-length Bid is sufficient to establish Bid/t(n)-Bid interaction. Interestingly, the L35A Bid mutant is as effective as t(c)-Bid in inducing apoptosis and binding Bcl-X(L). We propose that the intramolecular interaction involving the BH3-like and BH3 domains serves to regulate the pro-apoptotic potential of Bid.


Subject(s)
Apoptosis , Carrier Proteins/chemistry , Amino Acid Sequence , BH3 Interacting Domain Death Agonist Protein , Carrier Proteins/physiology , Structure-Activity Relationship
20.
Clin Lab Haematol ; 20(4): 239-44, 1998 Aug.
Article in English | MEDLINE | ID: mdl-9777271

ABSTRACT

Carnosine and anserine, the bioactive peptides found in most meats and fish, were tested for their ability to modulate neutrophil and U937 cell function, specifically with respect to respiratory burst, interleukin-1 beta production and apoptosis. Both peptides increased the respiratory burst and interleukin-1 beta production of human neutrophils but not of U937 cells. They suppressed apoptosis of human neutrophils but enhanced apoptosis of U937 cells as assessed by DNA strand breaks. These results suggest that carnosine and anserine have the capacity to modulate the immune response at least in human neutrophils.


Subject(s)
Anserine/pharmacology , Carnosine/pharmacology , Neutrophils/physiology , Apoptosis/drug effects , Humans , Interleukin-1/biosynthesis , Neutrophils/drug effects , Respiratory Burst/drug effects , Superoxides/metabolism , U937 Cells/drug effects
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