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Chu D, Kakazu N, Gorrin-Rivas MJ, Lu HP, Kawata M, Abe T, Ueda K, Adachi Y. Cloning and characterization of LUN, a novel ring finger protein that is highly expressed in lung and specifically binds to a palindromic sequence. J Biol Chem 2001; 276:14004-13. [PMID: 11278651 DOI: 10.1074/jbc.m010262200] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We isolated cDNAs encoding a novel RING finger protein (LUN), the mRNAs of which were expressed at high levels in the lung. In situ hybridization revealed that LUN mRNAs were expressed in the alveolar epithelium of the lung. The LUN gene locus was assigned to chromosome 9p21, which contains candidate tumor suppressor genes associated with loss of heterozygosity in more than 86% of small cell lung cancers. We clarified that LUN is localized to the nucleus and reveals Zn(2+)-dependent DNA binding activity. The region from amino acids 51 to 374 of LUN is responsible for DNA binding. Furthermore, we identified a novel palindromic binding consensus (5'-TCCCAGCACTTTGGGA-3') for the LUN binding. Interestingly, this LUN binding palindromic sequence is found in the upstream transcriptional regulatory region of the E-cadherin gene and two intervening regions of the talin gene. Our results suggested that LUN might be an important trans-acting transcriptional regulator for lung cancer-associated genes including E-cadherin and talin genes.
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MESH Headings
- Amino Acid Sequence
- Base Sequence
- Binding Sites
- Blotting, Northern
- Cadherins/metabolism
- Carrier Proteins
- Cations
- Cell Nucleus/metabolism
- Chromosome Mapping
- Chromosomes, Human, Pair 9
- Cloning, Molecular
- DNA/metabolism
- DNA, Complementary/metabolism
- DNA-Binding Proteins/chemistry
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Epithelium/metabolism
- Forkhead Transcription Factors
- Gene Library
- Glutathione Transferase/metabolism
- HeLa Cells
- Humans
- In Situ Hybridization
- In Situ Hybridization, Fluorescence
- Loss of Heterozygosity
- Lung/metabolism
- Molecular Sequence Data
- Neoplasm Proteins
- Nuclear Proteins
- Protein Binding
- Protein Structure, Tertiary
- Pulmonary Alveoli/metabolism
- RNA, Messenger/metabolism
- Recombinant Fusion Proteins/metabolism
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Tissue Distribution
- Trans-Activators/biosynthesis
- Trans-Activators/chemistry
- Trans-Activators/genetics
- Transcription Factors
- Transcription, Genetic
- Transfection
- Ubiquitin-Protein Ligases
- Zinc/metabolism
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Liu C, Chu D, Wideman RD, Houliston RS, Wong HJ, Meiering EM. Thermodynamics of denaturation of hisactophilin, a beta-trefoil protein. Biochemistry 2001; 40:3817-27. [PMID: 11300762 DOI: 10.1021/bi002609i] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hisactophilin is a histidine-rich pH-dependent actin-binding protein from Dictyostelium discoideum. The structure of hisactophilin is typical of the beta-trefoil fold, a common structure adopted by diverse proteins with unrelated primary sequences and functions. The thermodynamics of denaturation of hisactophilin have been measured using fluorescence- and CD-monitored equilibrium urea denaturation curves, pH-denaturation, and thermal denaturation curves, as well as differential scanning calorimetry. Urea denaturation is reversible from pH 5.7 to pH 9.7; however, thermal denaturation is highly reversible only below pH approximately 6.2. Reversible denaturation by urea and heat is well fit using a two-state transition between the native and the denatured states. Urea denaturation curves are best fit using a quadratic dependence of the Gibbs free energy of unfolding upon urea concentration. Hisactophilin has moderate, roughly constant stability from pH 7.7 to pH 9.7; however, below pH 7.7, stability decreases markedly, most likely due to protonation of histidine residues. Enthalpic effects of histidine ionization upon unfolding also appear to be involved in the occurrence of cold unfolding of hisactophilin under relatively mild solution conditions. The stability data for hisactophilin are compared with data on hisactophilin function, and with data for two other beta-trefoil proteins, human interleukin-1beta, and basic fibroblast growth factor.
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Zhou Q, Chu D, Gao X. [A matched case-control study on direct economic costs of four kinds of nosocomial infections]. ZHONGHUA LIU XING BING XUE ZA ZHI = ZHONGHUA LIUXINGBINGXUE ZAZHI 2001; 22:133-6. [PMID: 11860864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To evaluate the direct economic costs of four major kinds of nosocomial infections such as nosocomial pneumonia, urinary tract infection, deep surgical wound infection and intracranial infection. METHODS A matched case-control study was conducted among 95 pairs of hospitalized patients to investigate the direct economic costs of nosocomial infections. RESULTS The average medical cost for patients in the case group was 38 741 RMB Yuan, 20 365 Yuan more than that in the control group patients (P < 0.0001). The largest part of extra costs was found in drug expenses, taking up 62.07%, while other extra costs such as non-drug therapies, blood transmission and laboratory examinations, accounted for 10.32%, 7.40% and 5.72% respectively. Extra economic burden caused by nosocomial infections varied in different degrees with different departments, with the heaviest found in the department of tumourology and hematology at an average extra cost of 34 944 Yuan. The average extra charges in case group caused by nosocomial pneumonia, urinary tract infection, deep surgical wound infection and intracranial infection were 31 940 Yuan, 7 436 Yuan, 17 332 Yuan and 17 349 Yuan respectively. The average length of hospital stay was 50.57 days in case group and 25.22 days in control group, showing a 25.53 extra days (P < 0.0001) of hospitalization due to nosocomial infections. CONCLUSION Nosocomial infections had significantly added to the economic burden of managing the underlying diseases, led to prolonged hospitalization of the patients and lowered the turnover rate of hospital bed. There is a need to call for better infection control program, which would bring tremendous social and economic profits.
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Bo S, Ju J, Chu D. [Clinical study on Shenning Mixture in treating IgA nephropathy]. ZHONGGUO ZHONG XI YI JIE HE ZA ZHI ZHONGGUO ZHONGXIYI JIEHE ZAZHI = CHINESE JOURNAL OF INTEGRATED TRADITIONAL AND WESTERN MEDICINE 2000; 20:729-30. [PMID: 11938804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
OBJECTIVE To study the clinical therapeutic effect of Shenning Mixture (SNM) in treating IgA nephropathy. METHODS Patients were treated separately with SNM or prednisone by randomized grouping. The criteria, including clinical symptoms, signs, hematuria, albuminuria and immune globulin were observed. RESULTS The total effective rate and the complete remission rate in the SNM group were 97.1% and 45.7% respectively, while in the control group, they were 37.1% and 8.6% respectively. Comparison of the two groups showed that the therapeutic effect in the former was better than that in the latter significantly, P < 0.01. The hematuria and albuminuria extenuated and serum IgA lowered more significantly in the SNM group than those in the control group (P < 0.05, P < 0.01). CONCLUSION SNM has obvious therapeutic effect on the hematuria and albuminuria in treating IgA nephropathy.
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Uftring SJ, Chu D, Alperin N, Levin DN. The mechanical state of intracranial tissues in elderly subjects studied by imaging CSF and brain pulsations. Magn Reson Imaging 2000; 18:991-6. [PMID: 11121703 DOI: 10.1016/s0730-725x(00)00195-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The biomechanical properties of intracranial tissues influence the mechanical coupling of brain and CSF oscillations to the driving vascular pulsations. Dynamic phase contrast MRI was used to measure the transfer functions that characterize these couplings in normal elderly subjects and patients with Alzheimer's disease. The transfer functions of both groups were significantly different from the previously reported transfer functions of normal young subjects. The data show that vascular pulsations tend to cause greater spinal cord movements and smaller CSF oscillations in the older subjects than in the younger ones. These results are likely to be due to age-related changes in the mechanical state of intracranial tissues.
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Stanton TK, Chu D, Wiebe PH, Eastwood RL, Warren JD. Acoustic scattering by benthic and planktonic shelled animals. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2000; 108:535-550. [PMID: 10955618 DOI: 10.1121/1.429584] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Acoustic backscattering measurements and associated scattering modeling were recently conducted on a type of benthic shelled animal that has a spiral form of shell (Littorina littorea). Benthic and planktonic shelled animals with this shape occur on the seafloor and in the water column, respectively, and can be a significant source of acoustic scattering in the ocean. Modeling of the scattering properties allows reverberation predictions to be made for sonar performance predictions as well as for detection and classification of animals for biological and ecological applications. The studies involved measurements over the frequency range 24 kHz to 1 MHz and all angles of orientation in as small as 1 degree increments. This substantial data set is quite revealing of the physics of the acoustic scattering by these complex shelled bodies and served as a basis for the modeling. Specifically, the resonance structure of the scattering was strongly dependent upon angle of orientation and could be traced to various types of rays (e.g., subsonic Lamb waves and rays entering the opercular opening). The data are analyzed in both the frequency and time domain (compressed pulse processing) so that dominant scattering mechanisms could be identified. Given the complexity of the animal body (irregular elastic shell with discontinuities), approximate scattering models are used with only the dominant scattering properties retained. Two models are applied to the data, both approximating the body as a deformed sphere: (1) an averaged form of the exact modal-series-based solution for the spherical shell, which is used to estimate the backscattering by a deformed shell averaged over all angles of orientation, and produces reasonably accurate predictions over all k1a(esr) (k1 is the acoustic wave number of the surrounding water and a(esr) is the equivalent spherical radius of the body), and (2) a ray-based formula which is used to estimate the scattering at fixed angle of orientation, but only for high k1a(esr). The ray-based model is an extension of a model recently developed for the shelled zooplankton Limacina retroversa that has a shape similar to that of the Littorina littorea but swims through the water [Stanton et al., J. Acoust. Soc. Am. 103, 236-253 (1998b)]. Applications of remote detection and classification of the seafloor and water column in the presence of shelled animals are discussed.
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107
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Chu D, Huttenlocher PR, Levin DN, Towle VL. Reorganization of the hand somatosensory cortex following perinatal unilateral brain injury. Neuropediatrics 2000; 31:63-9. [PMID: 10832579 DOI: 10.1055/s-2000-7475] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Functional magnetic resonance imaging was used to map the hand somatosensory cortices of nine hemiparetic young adult patients with perinatal unilateral brain injury in the sensorimotor area and five normal subjects. Stimulation of the paretic hand by periodic manual squeezing produced activation in the contralateral hemisphere of three patients and in the ipsilateral hemisphere of three other patients. Paretic hand stimulation produced no activation in either hemisphere of the remaining three patients. Therefore, one-third of the patients demonstrated functional "plasticity" of the brain in the form of inter-hemispheric relocation of the hand somatosensory function. The volume and pattern of activation for both hands was altered for those patients that showed evidence of cortical reorganization to the opposite hemisphere. This differs from the hand motor system, which exhibited inter-hemispheric reorganization in a higher proportion of a related group of hemiparetic subjects.
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109
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Abstract
BACKGROUND Several studies report coexistent or subsequent primary tumors (SPT) among patients with malignant melanoma (MM), with the rate of incidence ranging from 1.5-20% depending on the sample size and the length and completeness of follow-up. METHODS The authors followed a cohort of patients with cutaneous MM who were diagnosed and treated at the City of Hope National Medical Center to determine the incidence rate of SPT and associated risk factors. Five hundred eighty-five patients (median age at diagnosis, 43 years) were diagnosed and treated for MM between 1952 and 1996 and followed for a median of 6.5 years (range, 0.0-37.0 years). Ninety-six percent of the cohort had been treated by surgery alone. RESULTS Thirty-seven patients developed an SPT. These included skin cancers (n = 23), carcinoma of the urinary bladder, breast carcinoma, and lymphoma (n = 3 each), lung carcinoma and prostate carcinoma (n = 2 each), and cervical carcinoma (n = 1). The estimated cumulative rate of incidence after MM was 5% at 5 years for any SPT, 3.7% for a second skin cancer, and 1.1% for a second solid tumor. Overall, the current cohort of MM patients was found to be at an increased risk for developing a subsequent melanoma (standardized incidence ratio [SIR], 4.5; 95% confidence interval [95% CI], 1.2-10.0) when compared with the general population. Older men (age > 50 years at the time of diagnosis of MM) were at an increased risk of developing subsequent bladder carcinoma (SIR, 6.4; 95% CI, 1.2-15.7). CONCLUSIONS Patients diagnosed with MM are at an increased risk of developing subsequent MM and bladder carcinoma. Issues to be addressed in future studies include interactions between environmental exposures and genetic susceptibility and the identification of individuals at increased risk.
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Correia I, Chu D, Chou YH, Goldman RD, Matsudaira P. Integrating the actin and vimentin cytoskeletons. adhesion-dependent formation of fimbrin-vimentin complexes in macrophages. J Cell Biol 1999; 146:831-42. [PMID: 10459017 PMCID: PMC2156141 DOI: 10.1083/jcb.146.4.831] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Cells adhere to the substratum through specialized structures that are linked to the actin cytoskeleton. Recent studies report that adhesion also involves the intermediate filament (IF) and microtubule cytoskeletons, although their mechanisms of interaction are unknown. Here we report evidence for a novel adhesion-dependent interaction between components of the actin and IF cytoskeletons. In biochemical fractionation experiments, fimbrin and vimentin coprecipitate from detergent extracts of macrophages using vimentin- or fimbrin-specific antisera. Fluorescence microscopy confirms the biochemical association. Both proteins colocalized to podosomes in the earliest stages of cell adhesion and spreading. The complex is also found in filopodia and retraction fibers. After detergent extraction, fimbrin and vimentin staining of podosomes, filopodia, and retraction fibers are lost, confirming that the complex is localized to these structures. A 1:4 stoichiometry of fimbrin binding to vimentin and a low percentage (1%) of the extracted vimentin suggest that fimbrin interacts with a vimentin subunit. A fimbrin-binding site was identified in the NH(2)-terminal domain of vimentin and the vimentin binding site at residues 143-188 in the CH1 domain of fimbrin. Based on these observations, we propose that a fimbrin-vimentin complex may be involved in directing the assembly of the vimentin cytoskeleton at cell adhesion sites.
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111
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Shen J, Chu D, Zhang Q, Zhang W. Developing a census data system in China. Int Stat Rev 1999; 67:173-86. [PMID: 12179589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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112
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Kuperman VY, Chu D, Alley MT. MR imaging of flow with locally high spatial resolution. Magn Reson Imaging 1999; 17:699-704. [PMID: 10372523 DOI: 10.1016/s0730-725x(98)00222-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Locally focused magnetic resonance imaging (LF MRI) allows imaging with variable spatial resolution within the field of view (FOV). Because LF MRI uses a priori information to provide locally high resolution in regions with rapid spatial variations in intensity (e.g., blood/tissue interface), it allows accurate reproduction of intense sharp edges in the specimen without blurring and truncation artifacts. This study employs LF MRI for 3D imaging of stationary and pulsatile flow. In the implemented version of LF MRI analytically defined basis functions are used to determine image intensity in regions depicted with low or high resolution. It is demonstrated that LF MRI of flow allows a significant (i.e. 3-4 times) reduction in scan time as compared to conventional FT MRI. It is also shown that LF images of pulsatile flow have a decreased appearance of ghosting artifacts as compared to the images reconstructed by using the conventional method.
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Chu D, Levin DN, Alperin N. Assessment of the biomechanical state of intracranial tissues by dynamic MRI of cerebrospinal fluid pulsations: a phantom study. Magn Reson Imaging 1998; 16:1043-8. [PMID: 9839988 DOI: 10.1016/s0730-725x(98)00142-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We used a cranial phantom to investigate how intracranial mechanical factors [brain compliance and the resistance to the flow of cerebrospinal fluid (CSF)] affect the way in which CSF pulsations are driven by pulsatile transcranial blood flow. Dynamic phase-contrast magnetic resonance imaging (MRI) was used to measure the transfer function between vascular pulsations and pulsatile response of the CSF below the foramen magnum of the phantom. We found that the coupling between the high frequency components of cervical CSF flow and transcranial blood flow was decreased when the phantom was modified to simulate increased brain compliance and increased resistance to CSF flow.
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Oleksijew A, Meulbroek J, Ewing P, Jarvis K, Mitten M, Paige L, Tovcimak A, Nukkula M, Chu D, Alder JD. In vivo efficacy of ABT-255 against drug-sensitive and -resistant Mycobacterium tuberculosis strains. Antimicrob Agents Chemother 1998; 42:2674-7. [PMID: 9756775 PMCID: PMC105917 DOI: 10.1128/aac.42.10.2674] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Current therapy for pulmonary tuberculosis involves 6 months of treatment with isoniazid, pyrazinamide, rifampin, and ethambutol or streptomycin for reliable treatment efficacy. The long treatment period increases the probability of noncompliance, leading to the generation of multidrug-resistant isolates of Mycobacterium tuberculosis. A treatment option that significantly shortened the course of therapy, or a new class of antibacterial effective against drug-resistant M. tuberculosis would be of value. ABT-255 is a novel 2-pyridone antibacterial agent which demonstrates in vitro potency and in vivo efficacy against drug-susceptible and drug-resistant M. tuberculosis strains. By the Alamar blue reduction technique, the MIC of ABT-255 against susceptible strains of M. tuberculosis ranged from 0.016 to 0.031 microg/ml. The MIC of ABT-255 against rifampin- or ethambutol-resistant M. tuberculosis isolates was 0.031 microg/ml. In a murine model of pulmonary tuberculosis, 4 weeks of oral ABT-255 therapy produced a 2- to 5-log10 reduction in viable drug-susceptible M. tuberculosis counts from lung tissue. Against drug-resistant strains of M. tuberculosis, ABT-255 produced a 2- to 3-log10 reduction in viable bacterial counts from lung tissue. ABT-255 is a promising new antibacterial agent with activity against M. tuberculosis.
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Chu D, Grube B, Ellenhom J, Paz B, Wagman L. The dominant sentinel node in breast cancer: A new technique. Eur J Cancer 1998. [DOI: 10.1016/s0959-8049(98)80217-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Houghton A, Coit D, Bloomer W, Buzaid A, Chu D, Eisenburgh B, Guitart J, Johnson T, Miller S, Sener S, Tanabe K, Thompson J, Urist M, Walker M. NCCN melanoma practice guidelines. National Comprehensive Cancer Network. ONCOLOGY (WILLISTON PARK, N.Y.) 1998; 12:153-77. [PMID: 9699216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Wang J, Chu D, Sun Y. [The role of recombinant interferon alpha-2b in the treatment of advanced malignancies]. ZHONGHUA ZHONG LIU ZA ZHI [CHINESE JOURNAL OF ONCOLOGY] 1998; 20:63-4. [PMID: 10921063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
OBJECTIVE To identify the efficacy and toxicity of recombinant interferon alpha-2b in the treatment of advanced malignancis. METHODS Interferon alpha-2b was administered intra-muscularly, the escalating dosage being 3 x 10(6) IU, twice in the first week, 6 x 10(6) IU twice in the second week and thereafter 9 x 10(6) IU twice weekly until the 8th week. RESULTS Among 102 patients, 90 were eva luable. The overall response rate (RR) was 16.7%. The RR in patients with renal cell careinoma was 10.8% (4/37, with 2 complete and 2 partial responses), that in patients with malignant melanoma was 14.3% (4/28, 4 partial responses), it was 50% (4/8, 4 partial responses) in malignant lymphoma and 20% (3/15, 3 partial responses) in breast cancer. The median response duration was 40 months in the patients with complete response, while only 4.8 months in patients with partial response. The major adverse reactions were flu-like syndrome, while gastro-intestinal reactions and bone marrow suppression were mild. CONCLUSION Recombinant interferon alpha-2b has antitumor activity in patients with advanced renal cell carcinoma, malignant melanoma and malignant lymphoma. It could be considered as a second line treatment regimen.
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Stanton TK, Chu D, Wiebe PH, Martin LV, Eastwood RL. Sound scattering by several zooplankton groups. I. Experimental determination of dominant scattering mechanisms. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 1998; 103:225-235. [PMID: 9440325 DOI: 10.1121/1.421469] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The acoustic scattering properties of live individual zooplankton from several gross anatomical groups have been investigated. The groups involve (1) euphausiids (Meganyctiphanes norvegica) whose bodies behave acoustically as a fluid material, (2) gastropods (Limacina retroversa) whose bodies include a hard elastic shell, and (3) siphonophores (Agalma okeni or elegans and Nanomia cara) whose bodies contain a gas inclusion (pneumatophore). The animals were collected from ocean waters off New England (Slope Water, Georges Bank, and the Gulf of Maine). The scattering properties were measured over parts or all of the frequency range 50 kHz to 1 MHz in a laboratory-style pulse-echo setup in a large tank at sea using live fresh specimens. Individual echoes as well as averages and ping-to-ping fluctuations of repeated echoes were studied. The material type of each group is shown to strongly affect both the overall echo level and pattern of the target strength versus frequency plots. In this first article of a two-part series, the dominant scattering mechanisms of the three animal types are determined principally by examining the structure of both the frequency spectra of individual broadband echoes and the compressed pulse (time series) output. Other information is also used involving the effect on overall levels due to (1) animal orientation and (2) tissue in animals having a gas inclusion (siphonophores). The results of this first paper show that (1) the euphausiids behave as weakly scattering fluid bodies and there are major contributions from at least two parts of the body to the echo (the number of contributions depends upon angle of orientation and shape), (2) the gastropods produce echoes from the front interface and possibly from a slow-traveling circumferential (Lamb) wave, and (3) the gas inclusion of the siphonophore dominates the echoes, but the tissue plays a role in the scattering and is especially important when analyzing echoes from individual animals on a ping-by-ping basis. The results of this paper serve as the basis for the development of acoustic scattering models in the companion paper [Stanton et al., J. Acoust. Soc. Am. 103, 236-253 (1998)].
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Stanton TK, Chu D, Wiebe PH. Sound scattering by several zooplankton groups. II. Scattering models. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 1998; 103:236-253. [PMID: 9440326 DOI: 10.1121/1.421110] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Mathematical scattering models are derived and compared with data from zooplankton from several gross anatomical groups--fluidlike, elastic shelled, and gas bearing. The models are based upon the acoustically inferred boundary conditions determined from laboratory backscattering data presented in part I of this series [Stanton et al., J. Acoust. Soc. Am. 103, 225-235 (1998)]. The models use a combination of ray theory, modal-series solution, and distorted wave Born approximation (DWBA). The formulations, which are inherently approximate, are designed to include only the dominant scattering mechanisms as determined from the experiments. The models for the fluidlike animals (euphausiids in this case) ranged from the simplest case involving two rays, which could qualitatively describe the structure of target strength versus frequency for single pings, to the most complex case involving a rough inhomogeneous asymmetrically tapered bent cylinder using the DWBA-based formulation which could predict echo levels over all angles of incidence (including the difficult region of end-on incidence). The model for the elastic shelled body (gastropods in this case) involved development of an analytical model which takes into account irregularities and discontinuities of the shell. The model for gas-bearing animals (siphonophores) is a hybrid model which is composed of the summation of the exact solution to the gas sphere and the approximate DWBA-based formulation for arbitrarily shaped fluidlike bodies. There is also a simplified ray-based model for the siphonophore. The models are applied to data involving single pings, ping-to-ping variability, and echoes averaged over many pings. There is reasonable qualitative agreement between the predictions and single ping data, and reasonable quantitative agreement between the predictions and variability and averages of echo data.
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Stanton TK, Wiebe PH, Chu D. Differences between sound scattering by weakly scattering spheres and finite-length cylinders with applications to sound scattering by zooplankton. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 1998; 103:254-264. [PMID: 9440327 DOI: 10.1121/1.421135] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A modeling study was conducted to determine the conditions under which fluidlike zooplankton of the same volume but different shapes (spherical/cylindrical) have similar or dramatically different scattering properties. Models of sound scattering by weakly scattering spheres and cylinders of finite length used in this analysis were either taken from other papers or derived and herein adapted for direct comparison over a range of conditions. The models were examined in the very low- (ka << 1, kL << 1), moderately low- (ka << 1, kL > or = 1), and high-frequency regions (ka >> 1, kL >> 1), where k is the acoustic wave number, a is the radius (spherical or cylindrical) of the body, and L is the length of the cylinders (for an elongated body with L/a = 10, "moderately low" corresponds to the range 0.1 < or = ka < or = 0.5). Straight and bent cylinder models were evaluated for broadside incidence, end-on incidence, and averages over various distributions of angle of orientation. The results show that for very low frequencies and for certain distributions of orientation angles at high frequencies, the averaged scattering by cylinders will be similar, if not identical, to the scattering by spheres of the same volume. Other orientation distributions of the cylinders at high frequencies produce markedly different results. Furthermore, over a wide range of orientation distributions the scattering by spheres is dramatically different from that of the cylinders in the moderately low-frequency region and in the Rayleigh/geometric transition region: (1) the Rayleigh to geometric scattering turning point occurs at different points for the two cases when the bodies are constrained to have the same volume and (2) the functional dependence of the scattering levels upon the volume of the bodies in the moderately low-frequency region is quite often different between the spheres and cylinders because of the fact that the scattering by the cylinders is still directional in this region. The study demonstrates that there are indeed conditions under which different shaped zooplankton of the same volume will yield similar (ensemble average) scattering levels, but generally the shape and orientation distribution of the elongated bodies must be taken into account for accurate predictions.
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Pamidi S, Leo PJ, Saul B, Gelles J, Chu D. Postoperative mitral valve abscess. A case report. Angiology 1997; 48:749-52. [PMID: 9269146 DOI: 10.1177/000331979704800812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The authors report a case of a patient with postoperative perimitral bioprosthetic abscess and probable systemic embolization. The location of the abscess is not common and the use of porcine bioprostheses is supposedly associated with a low rate of embolic complications. Because of the high mortality and morbidity, it is stressed that patients with prosthetic valve endocarditis should be managed aggressively with surgery.
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Retchin SM, Brown RS, Yeh SC, Chu D, Moreno L. Outcomes of stroke patients in Medicare fee for service and managed care. JAMA 1997; 278:119-24. [PMID: 9214526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
CONTEXT Increasing numbers of Medicare beneficiaries have been enrolling in health maintenance organizations (HMOs) because HMO participation reduces out-of-pocket expenses, and the federal government views HMOs as a way to contain Medicare costs. However, results comparing outcomes and quality of care in HMOs vs fee for service (FFS) have been mixed, and outcomes after stroke have not been adequately assessed. OBJECTIVE To compare discharge destinations and survival rates following stroke in Medicare HMOs with similar FFS settings. DESIGN An observational study for 2 groups evaluating stroke patients' discharge destinations and survival times from the date of hospital admission. SETTING A total of 19 HMOs were selected from 12 states. The FFS sample was drawn from the same geographic areas. PATIENTS The sample included 402 HMO patients from 71 hospitals and 408 FFS patients from 60 hospitals. PROCESS AND OUTCOME MEASURES: Data were abstracted from medical records on demographics, clinical characteristics of stroke, comorbid illnesses, and discharge destinations following hospitalization. Data on survival were obtained from Medicare files and included 25 to 37 months of follow-up (median, 30.4 months, HMO; 31.1 months, FFS) from the date of hospital admission. RESULTS There were 109 patients who died during the hospitalization (49 HMO, 12.2%; 60 FFS, 14.7%), and a total of 410 patients had died by the end of follow-up (191 HMO, 47.5%; 219 FFS, 53.7%). Approximately one fourth of both groups had do-not-resuscitate orders (HMO, 25.4%; FFS, 27.9%; P=.68). After controlling for age, marital status, and characteristics of dependency at discharge, HMO patients were more likely than FFS patients to be sent to nursing homes (HMO, 41.8%; FFS, 27.9%; P=.001) and less likely to be discharged to rehabilitation hospitals or units (HMO, 16.2%; FFS, 23.4%; P=.03). At follow-up, no significant differences in relative risk of dying were found between HMO and FFS groups (relative risk, 0.96; 95% confidence interval, 0.73-1.26; P=.77). CONCLUSIONS Patients in Medicare HMOs who experience strokes are more likely to be discharged to nursing homes and less likely to go to rehabilitation facilities following the acute event. However, they have similar survival patterns compared with comparable patients in FFS settings after adjusting for other factors.
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Chu D, Ogilvy CS. Isovolemic hemodilution with purified and polymerized bovine hemoglobin in a rabbit model of focal cerebral ischemia. CHINESE J PHYSIOL 1997; 40:63-9. [PMID: 9303242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Isovolemic hemodilution with polymerized bovine hemoglobin (PoBH) was tested as a means of preventing infarction in a rabbit model of focal cerebral ischemia. The animals were divided into one control group and one hemodilution group. All animals underwent two hours of ischemia, caused by clipping the left internal carotid artery, the anterior cerebral artery, and the middle cerebral artery, followed by 4 hours of reperfusion. In the control group, the hematocrit was not manipulated (mean +/- SE: 33.8 +/- 1.3%), while in the hemodilution group, the Hct was reduced to 12.5 +/- 1.9% by exchange of blood with PoBH, before clipping the cerebral vessels. Staining with 2,3,5- triphenyltetrazolium chloride (TTC) was used to evaluate the infarct size. The infarct volume was 427 +/- 52 mm3 in the control animal, and 1026 +/- 311 mm3 (p < 0.01 when compared with the control group) in the animal hemodiluted with PoBH. PoBH hemodilution was found to be associated with vasoconstriction. This pathological vasoconstriction probably counteracted any beneficial effects from the lowered viscosity and explains our negative results. Vasoconstriction has to be overcome before hemodilution can have its beneficial effect in reducing the cerebral ischemia.
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Chu D, Shi PK, Wu CM. Transthoracic endoscopic sympathectomy for treatment of hyperhidrosis palmaris. Kaohsiung J Med Sci 1997; 13:162-8. [PMID: 9109303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The objective of this study was to determine the effectiveness of modified transthoracic endoscopic sympathectomy (TES) being used in our institute for treatment of hyperhidrosis palmaris (HP). One hundred and eight cases of HP were treated using TES from June 1991 to June 1992. All underwent TES bilaterally. Palmar temperature was monitored during the operation as an indicator of a successful lesioning of the sympathetic trunk at the T2-level. The ages of the patients ranged from 10 to 61 years. Fifty-one percent of these patients had a positive family history. Seventy-three percent had onset during childhood. Eighty-nine percent had excessive plantar sweating in addition to hyperhidrosis palmaris. The increase in palmar temperature after lesioning the sympathetic trunk was inversely related to the preoperative temperature of the palms (r = 0.81, p < 0.005). Our treatment resulted in improvement of palmar sweating in all of the patients. Decrease of plantar sweating was also noted in 68% of the patients at follow up. No neurological deficits were found. Transient post-operative chest discomfort and compensatory hyperhidrosis (87%) were the most common complications. TES is an effective method for treating patients with HP, with a shorter operation time, fewer hospital days, and a better cosmetic result, as compared with the dorsal approach for thoracic sympathectomy.
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Chu D, Towle V, Syed I, Munson R, Grzeszczuk R, Pelizzari C, Spire JP. A comparison of sensory fMRI signal locations with SEP dipoles and gyral anatomy. Neuroimage 1996. [DOI: 10.1016/s1053-8119(96)80327-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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