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Smith JJ, Garratt AM, Guest M, Greenhalgh RM, Davies AH. Evaluating and improving health-related quality of life in patients with varicose veins. J Vasc Surg 1999; 30:710-9. [PMID: 10514210 DOI: 10.1016/s0741-5214(99)70110-2] [Citation(s) in RCA: 191] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
PURPOSE We set out to assess the new Aberdeen Varicose Veins Questionnaire (Aberdeen Questionnaire) for the properties necessary for a valid measure of health outcome, to determine quality of life of patients with varicose veins, and to determine the effect of surgery on quality of life. METHODS A prospective consecutive cohort of 137 patients undergoing varicose vein surgery completed the self-administered SF-36 and Aberdeen Questionnaire and 25 questions relating to the symptoms and concerns of patients with varicose veins. Follow-up was done by repeated questionnaires 6 weeks after surgery. The Aberdeen Questionnaire was assessed for reliability, validity, responsiveness, and practicality. Quality of life of patients with varicose veins was compared with an age- and sex-matched sample of the general population. RESULTS Reliability estimates for the 8 scales short-form health survey (SF-36) and the Aberdeen Questionnaire were all above 0.7 (Cronbach's alpha). The Aberdeen Questionnaire had a highly significant correlation (r = 0. 74, P <.0001) with the patients' symptoms and concerns questionnaire, which is evidence of its validity. Patients with varicose veins score lower than United Kingdom norms (P <.001) in the physical domains of the SF-36, indicating worse health. After surgery, the SF-36 scores improved in all 8 domains of health, reaching significance in "Mental Health" (P <.05) and approaching significance in "General Health" (P =.066). The Health Transition Item of the SF-36 and the Aberdeen Questionnaire both showed a highly significant improvement in health (P <.001). CONCLUSION The Aberdeen Questionnaire is a valid measure of quality of life for patients with varicose veins. Persons with varicose veins have a reduced quality of life compared with the general population, and this discrepancy is significantly improved at 6 weeks by operating on them.
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Abstract
Ureterosciatic herniation is a rare benign event that can mimic diverticulosis or irritable bowel syndrome. This entity has been managed by a number of open surgical techniques. Laparoscopic repair of this entity enabled us to identify the defect, interpose mesh, and obliterate the hernia defect with minimal morbidity. This represents the first report of laparoscopic repair of a ureterosciatic hernia.
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Taylor AL, Schwiebert LM, Smith JJ, King C, Jones JR, Sorscher EJ, Schwiebert EM. Epithelial P2X purinergic receptor channel expression and function. J Clin Invest 1999; 104:875-84. [PMID: 10510328 PMCID: PMC408558 DOI: 10.1172/jci7270] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
P2X purinergic receptor (P2XR) channels bind ATP and mediate Ca(2+) influx--2 signals that stimulate secretory Cl(-) transport across epithelia. We tested the hypotheses that P2XR channels are expressed by epithelia and that P2XRs transduce extracellular ATP signals into stimulation of Cl(-) transport across epithelia. Electrophysiological data and mRNA analysis of human and mouse pulmonary epithelia and other epithelial cells indicate that multiple P2XRs are broadly expressed in these tissues and that they are active on both apical and basolateral surfaces. Because P2X-selective agonists bind multiple P2XR subtypes, and because P2X agonists stimulate Cl(-) transport across nasal mucosa of cystic fibrosis (CF) patients as well as across non-CF nasal mucosa, P2XRs may provide novel targets for extracellular nucleotide therapy of CF.
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MESH Headings
- 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid/pharmacology
- Amiloride/pharmacology
- Animals
- Base Sequence
- Bumetanide/pharmacology
- Cell Line
- Cells, Cultured
- DNA Probes
- DNA, Complementary
- Epithelial Cells/drug effects
- Epithelial Cells/physiology
- Humans
- Intestinal Mucosa/physiology
- Liver/physiology
- Lung/physiology
- Mice
- Models, Biological
- Molecular Sequence Data
- Pancreas/physiology
- Patch-Clamp Techniques
- Protein Isoforms/genetics
- Protein Isoforms/physiology
- RNA, Messenger/metabolism
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2/physiology
- Respiratory Mucosa/physiology
- Sequence Alignment
- Sequence Homology, Nucleic Acid
- Transcription, Genetic
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104
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Smith JJ, Berlin L. Informed consent when using medical devices for indications not approved by the Food and Drug Administration. AJR Am J Roentgenol 1999; 173:879-82. [PMID: 10511140 DOI: 10.2214/ajr.173.4.10511140] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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106
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Abstract
In the past few years, it has become widely appreciated that apoptotic cell death generally involves activation of a family of proteases, the caspases, which undermine the integrity of the cell by cleavage of critical intracellular substrates. Caspases, which are synthesized as inactive zymogens, are themselves caspase substrates and this cleavage leads to their activation. Hence, the potential exists for cascades of caspases leading to cell death. However, it has been recently recognized that another, perhaps more prominent route to caspase activation, involves the mitochondria. Upon receipt of apoptotic stimuli, either externally or internally generated, cells initiate signaling pathways which converge upon the mitochondria to promote release of cytochrome C to the cytoplasm; cytochrome c, thus released, acts as a potent cofactor in caspase activation. Even cell surface "death receptors" such as Fas, which can trigger direct caspase activation (and potentially a caspase cascade), appear to utilize mitochondria as part of an amplification mechanism; it has been recently demonstrated that activated caspases can cleave key substrates to trigger mitochondrial release of cytochrome c, thereby inducing further caspase activation and amplifying the apoptotic signal. Therefore, mitochondria play a central role in apoptotic cell death, serving as a repository for cytochrome c.
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107
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Lester DR, Ross JJ, Smith JJ, Elliott RC, Reid JB. Gibberellin 2-oxidation and the SLN gene of Pisum sativum. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 1999; 19:65-73. [PMID: 10417727 DOI: 10.1046/j.1365-313x.1999.00501.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Two cDNAs encoding gibberellin 2-oxidases were isolated from maturing pea seeds. The first, PsGA2ox1, was isolated by activity screening of a Lambda-ZAP cDNA library excised into phagemid form and expressed in Escherichia coli. The second, PsGA2ox2, was obtained initially as a PCR product using degenerate primers designed according to conserved regions of plant 2-oxoglutarate-dependent dioxygenases. E. coli heterologous expression products of PsGA2ox1 and PsGA2ox2 converted GA1 to GA8, as shown by HPLC-radiocounting, and gas chromatography-MS. PsGA2ox1 converted GA20 to GA29, but GA20 was a poor substrate for the PsGA2ox2 expression product. Furthermore, PsGA2ox1 converted GA29 to GA29-catabolite at a low level of efficiency while PsGA2ox2 did not catalyse this step. A cDNA of PsGA2ox1 isolated from plants of genotype sln contained a single base deletion which was predicted to produce a truncated protein and gibberellin 2-oxidase activity could not be demonstrated from this cDNA. A 10 bp size difference between the introns of the SLN and sln PsGA2ox1 genes was used to show co-segregation between the SLN and sln phenotypes and the size of the PCR products. PsGA2ox1 transcripts were more abundant in cotyledons than in shoots, while the reverse was the case for PsGA2ox2. The expression patterns of the genes, together with the effects of the sln mutation, indicate that PsGA2ox1 plays a major role in GA20 deactivation in both shoots and maturing seeds, while the PsGA2ox2 gene might be important for GA1 deactivation in the shoot.
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109
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Guest M, Smith JJ, Davies AH. Quality of life in patients with benign anorectal disorders. Br J Surg 1999; 86:843. [PMID: 10419332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
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110
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Shinopulos NM, Dann JA, Smith JJ. Patient selection and education for use of the CapSure (Re/Stor) continence shield. UROLOGIC NURSING 1999; 19:135-40. [PMID: 10633764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Stress urinary incontinence affects millions of women. Many treatment options are available, ranging from behavioral or nonsurgical therapies to surgical intervention. The clinical findings of a multicenter trial using the CapSure (Re/Stor) continence shield to evaluate the safety and efficacy of this device for treating women with stress urinary incontinence are reported here. Additionally, the role of patient education and selection is discussed.
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111
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Smith JJ, Rücknagel KP, Schierhorn A, Tang J, Nemeth A, Linder M, Herschman HR, Wahle E. Unusual sites of arginine methylation in Poly(A)-binding protein II and in vitro methylation by protein arginine methyltransferases PRMT1 and PRMT3. J Biol Chem 1999; 274:13229-34. [PMID: 10224081 DOI: 10.1074/jbc.274.19.13229] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Arginine methylation is a post-translational modification found mostly in RNA-binding proteins. Poly(A)-binding protein II from calf thymus was shown by mass spectrometry and sequencing to contain NG, NG-dimethylarginine at 13 positions in its amino acid sequence. Two additional arginine residues were partially methylated. Almost all of the modified residues were found in Arg-Xaa-Arg clusters in the C terminus of the protein. These motifs are distinct from Arg-Gly-Gly motifs that have been previously described as sites and specificity determinants for asymmetric arginine dimethylation. Poly(A)-binding protein II and deletion mutants expressed in Escherichia coli were in vitro substrates for two mammalian protein arginine methyltransferases, PRMT1 and PRMT3, with S-adenosyl-L-methionine as the methyl group donor. Both PRMT1 and PRMT3 specifically methylated arginines in the C-terminal domain corresponding to the naturally modified sites.
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112
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Spiegelberg BD, Xiong JP, Smith JJ, Gu RF, York JD. Cloning and characterization of a mammalian lithium-sensitive bisphosphate 3'-nucleotidase inhibited by inositol 1,4-bisphosphate. J Biol Chem 1999; 274:13619-28. [PMID: 10224133 DOI: 10.1074/jbc.274.19.13619] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Discovery of a structurally conserved metal-dependent lithium-inhibited phosphomonoesterase protein family has identified several potential cellular targets of lithium as used to treat manic depression. Here we describe identification of a novel family member using a "computer cloning" strategy. Human and murine cDNA clones encoded proteins sharing 92% identity and were highly expressed in kidney. Native and recombinant protein harbored intrinsic magnesium-dependent bisphosphate nucleotidase activity (BPntase), which removed the 3'-phosphate from 3'-5' bisphosphate nucleosides and 3'-phosphoadenosine 5'-phosphosulfate with Km and Vmax values of 0.5 microM and 40 micromol/min/mg. Lithium uncompetitively inhibited activity with a Ki of 157 microM. Interestingly, BPntase was competitively inhibited by inositol 1,4-bisphosphate with a Ki of 15 microM. Expression of mammalian BPntase complemented defects in hal2/met22 mutant yeast. These data suggest that BPntase's physiologic role in nucleotide metabolism may be regulated by inositol signaling pathways. The presence of high levels of BPntase in the kidney are provocative in light of the roles of bisphosphorylated nucleotides in regulating salt tolerance, sulfur assimilation, detoxification, and lithium toxicity. We propose that inhibition of human BPntase may account for lithium-induced nephrotoxicity, which may be overcome by supplementation of current therapeutic regimes with inhibitors of nucleotide biosynthesis, such as methionine.
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Travis SM, Conway BA, Zabner J, Smith JJ, Anderson NN, Singh PK, Greenberg EP, Welsh MJ. Activity of abundant antimicrobials of the human airway. Am J Respir Cell Mol Biol 1999; 20:872-9. [PMID: 10226057 DOI: 10.1165/ajrcmb.20.5.3572] [Citation(s) in RCA: 161] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Human airways produce several antimicrobial factors; the most abundant are lysozyme and lactoferrin. Despite their likely importance in preventing infection, and their possible key role in the pathogenesis of cystic fibrosis (CF), we know little about their antibacterial activity in the context of the CF airway. We found that abundant airway antimicrobial factors kill common CF pathogens, although Burkholderia was relatively resistant. To study the antibacterial activity, we developed a rapid, sensitive, and quantitative in vitro luminescence assay. Because NaCl concentrations may be elevated in CF airway surface liquid, we tested the effect of salt on antibacterial activity. Activity of individual factors and of airway lavage fluid was inhibited by high ionic strength, and it was particularly sensitive to divalent cations. However, it was not inhibited by nonionic osmolytes and thus did not require hypotonic liquid. The inhibition by ionic strength could be partially compensated by increased concentrations of antibacterial factors, thus there was no one unique salt concentration for inhibition. CF airway secretions also contain abundant mucin and elastase; however, these had no effect on antibacterial activity of lysozyme, lactoferrin, or airway lavage fluids. When studied at low NaCl concentrations, CF and non-CF airway lavage fluids contained similar levels of antibacterial activity. These results suggest approaches toward developing treatments aimed at preventing or reducing airway infections in individuals with CF.
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114
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Smith JJ. The specialty boards and antitrust: a legal perspective. THE JOURNAL OF CONTEMPORARY HEALTH LAW AND POLICY 1999; 10:195-219. [PMID: 10134810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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115
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Smith JJ, Gay SB, Maurer EJ, Matsumoto AH. Effect of Health Care Financing Administration regulation on radiology fellowship training. Acad Radiol 1999; 6:126-31. [PMID: 12680435 DOI: 10.1016/s1076-6332(99)80492-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
RATIONALE AND OBJECTIVES The purpose of this study was to assess the effect of Health Care Financing Administration (HCFA) regulations on radiology fellowship training. MATERIALS AND METHODS Surveys were sent to 157 fellowship program directors in body imaging and vascular/ interventional radiology. Questions addressed program accreditation status, faculty supervision of fellows, and any change in faculty supervision of fellows in response to HCFA's revised plan for Medicare Part B reimbursement. RESULTS Eighty of 157 (51%) surveys were returned. Thirty (37%) respondents indicated supervision of fellows had changed after institution of the new HCFA rules in July 1996. Vascular/interventional program directors (n = 25, 49%) were more likely to have changed their practice than body imaging program directors (n = 5, 17%). Nearly all respondents (29 of 30, 97%) indicating a change stated supervision had increased. Twenty-seven (33%) respondents also indicated faculty supervision was beyond that necessary for patient care and house staff education; most of these respondents (21 of 27, 78%) stated the new HCFA regulations were responsible. Many program directors also expressed concern the HCFA regulations might prevent fellows from obtaining sufficient experience to effectively learn independent clinical decision-making. CONCLUSION HCFA regulations intended to address attending physician billing practices at teaching institutions may have had the unintended effect of substantively altering the training of radiology fellows.
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116
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Smith JJ, Levine HJ. Systolic dysfunction of the ventricle in congestive heart failure: pathophysiology, diagnosis, and therapy. CONGESTIVE HEART FAILURE (GREENWICH, CONN.) 1999; 5:10-26. [PMID: 12189329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
Investigations into the pathophysiology and treatment of the failing left ventricle have yielded impressive results over the past three decades. Patients with systolic dysfunction have abnormalities of the molecular machinery and signaling of contraction which may be in-born or acquired, and result in the characteristic mechanical abnormalities associated with this condition. Correlation of these ultrastructural contractile abnormalities with the mechanical dysfunction observed clinically is complicated by alterations of preload and afterload which accompany systolic failure. The systemic consequences of contractile failure result in a cascade of neuroendocrine and cytokine activation which perpetuates a cycle of further myocardial dysfunction and systemic humoral response. Based on this neuroendocrine paradigm, pharmacologic intervention trials have yielded promising gains in survival and symptom status in patients with systolic dysfunction, particularly with the ACE inhibitors and the beta-adrenergic blockers. For patients with acute systolic failure the inotropic agents continue to be useful in short term support but chronic administration with these agents should be avoided because of enhanced mortality observed in virtually all placebo controlled trials. Finally, long-term mortality rates remain high in patients with systolic dysfunction despite current therapy, thus offering an opportunity for the novel approaches currently under investigation to substantially impact on patient outcomes. (c)1999 by CHF, Inc.
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117
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Guest M, Smith JJ, Davies AH. Quality of life in patients undergoing treatment for chronic radiation-induced rectal bleeding. Br J Surg 1999; 86:135-6. [PMID: 10027379 DOI: 10.1046/j.1365-2168.1999.0985c.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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118
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Smith JJ, Toogood GJ, Galland RB. Reconstruction for lower limb occlusive disease in the elderly. CARDIOVASCULAR SURGERY (LONDON, ENGLAND) 1999; 7:58-61. [PMID: 10073762 DOI: 10.1016/s0967-2109(98)00049-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To determine the acceptability of performing distal limb bypass for occlusive vascular disease in the over 75's. METHOD Patients undergoing surgery between January 1988 and December 1996 were included. Data were obtained from a card system, operating ledgers, admission diaries and hospital notes. RESULTS A total of 166 patients were identified. There were 69 women and 97 men, 79 were aged 75-79 years, 81 were 80-89 years and six older than 90 years. A total of 171 procedures were performed: infrainguinal bypass in 131 (77%), aorto-femoral bifurcation grafts in 10 (6%) and extra-anatomic bypass in 30 (17%). This represents 28.1% of all reconstructions for occlusive disease during this time. Nine patients (5.4%) died within 30 days and one (0.6%) required a major amputation. During the follow-up period (median 12 months), 14 major and 10 minor amputations were required. Ten patients underwent a second successful reconstructive procedure. CONCLUSION Reconstruction in this group of older patients can be carried out with acceptable 30-day mortality and limb salvage rates.
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119
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Bremer PJ, Osborne CM, Kemp RA, Smith JJ. Survival of Listeria monocytogenes in sea water and effect of exposure on thermal resistance. J Appl Microbiol 1998; 85:545-53. [PMID: 9750285 DOI: 10.1046/j.1365-2672.1998.853533.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Survival, recoverability and sublethal injury of two strains of Listeria monocytogenes, Scott A and an environmental strain KM, on exposure to sea water at 12.8 or 20.8 degrees C was determined using in situ diffusion chambers. Plate counts were used to assess recoverability and injury while 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) reduction was used to determine respiratory activity. T90 values (times for 10-fold decreases in numbers of recoverable cells) on non-selective medium (trypticase soya agar with 0.6% yeast extract) at 12.8 and 20.8 degrees C were 61.7 and 69.2 h for L. monocytogenes Scott A, and 103.0 and 67.0 h for L. monocytogenes KM, respectively. On selective medium (Oxford agar), T90 values at 12.8 and 20.8 degrees C were 60.6 and 56.9 h for L. monocytogenes Scott A, and 83.0 and 65.9 h for L. monocytogenes KM, respectively. With Scott A, the percentage of sublethally injured cells at 12.8 and 20.8 degrees C was 1.7 and 17.7%, respectively, while for KM the values were 19.0 and 1.6%, respectively. The fraction of cells reducing CTC but which were not recoverable on plating progressively increased on exposure to sea water. Listeria monocytogenes KM challenged at 58 degrees C showed an apparent increase in heat resistance after exposure to sea water at 20.8 degrees C for 7 d (D58 = 2.64 min) compared with before exposure (D58 = 1.24). This increase in thermal resistance was not apparent at temperatures greater than 63 degrees C, and analysis of the best-fit regression lines fitted to the thermal data obtained from the two cell populations indicated that their thermal resistance was not significantly different (P > 0.05) over the temperature range tested (58-62 degrees C).
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Zabner J, Smith JJ, Karp PH, Widdicombe JH, Welsh MJ. Loss of CFTR chloride channels alters salt absorption by cystic fibrosis airway epithelia in vitro. Mol Cell 1998; 2:397-403. [PMID: 9774978 DOI: 10.1016/s1097-2765(00)80284-1] [Citation(s) in RCA: 177] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cystic fibrosis (CF) is caused by the loss of functional CFTR Cl- channels. However, it is not understood how this defect disrupts salt and liquid movement in the airway or whether it alters the NaCl concentration in the thin liquid film covering the airway surface. Using a new approach, we found that CF airway surface liquid had a higher NaCl concentration than normal. Both CF and non-CF epithelia absorbed salt and liquid; however, expression of CFTR Cl- channels was required for maximal absorption. Thus, loss of CFTR elevates the salt concentration in CF airway surface liquid and in sweat by related mechanisms; the elevated NaCl concentration is due to a block in transcellular Cl- movement. The high NaCl may predispose CF airways to bacterial infections by inhibiting endogenous antibacterial defenses.
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Titorenko VI, Smith JJ, Szilard RK, Rachubinski RA. Pex20p of the yeast Yarrowia lipolytica is required for the oligomerization of thiolase in the cytosol and for its targeting to the peroxisome. J Biophys Biochem Cytol 1998; 142:403-20. [PMID: 9679140 PMCID: PMC2133052 DOI: 10.1083/jcb.142.2.403] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Pex mutants are defective in peroxisome assembly. In the pex20-1 mutant strain of the yeast Yarrowia lipolytica, the peroxisomal matrix protein thiolase is mislocalized exclusively to the cytosol, whereas the import of other peroxisomal proteins is unaffected. The PEX20 gene was isolated by functional complementation of the pex20-1 strain and encodes a protein, Pex20p, of 424 amino acids (47,274 D). Despite its role in the peroxisomal import of thiolase, which is targeted by an amino-terminal peroxisomal targeting signal-2 (PTS2), Pex20p does not exhibit homology to Pex7p, which acts as the PTS2 receptor. Pex20p is mostly cytosolic, whereas 4-8% is associated with high-speed (200,000 g) pelletable peroxisomes. In the wild-type strain, all newly synthesized thiolase is associated with Pex20p in a heterotetrameric complex composed of two polypeptide chains of each protein. This association is independent of PTS2. Pex20p is required for both the oligomerization of thiolase in the cytosol and its targeting to the peroxisome. Our data suggest that monomeric Pex20p binds newly synthesized monomeric thiolase in the cytosol and promotes the formation of a heterotetrameric complex of these two proteins, which could further bind to the peroxisomal membrane. Translocation of the thiolase homodimer into the peroxisomal matrix would release Pex20p monomers back to the cytosol, thereby permitting a new cycle of binding-oligomerization-targeting-release for Pex20p and thiolase.
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Brenner RJ, Lucey LL, Smith JJ, Saunders R. Radiology and medical malpractice claims: a report on the practice standards claims survey of the Physician Insurers Association of America and the American College of Radiology. AJR Am J Roentgenol 1998; 171:19-22. [PMID: 9648756 DOI: 10.2214/ajr.171.1.9648756] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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123
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Kuwana T, Smith JJ, Muzio M, Dixit V, Newmeyer DD, Kornbluth S. Apoptosis induction by caspase-8 is amplified through the mitochondrial release of cytochrome c. J Biol Chem 1998; 273:16589-94. [PMID: 9632731 DOI: 10.1074/jbc.273.26.16589] [Citation(s) in RCA: 296] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apoptosis often involves the release of cytochrome c from mitochondria, leading to caspase activation. However, in apoptosis mediated by CD95 (Fas/APO-1), caspase-8 (FLICE/MACH/Mch5) is immediately activated and, in principle, could process other caspases directly. To investigate whether caspase-8 could also act through mitochondria, we added active caspase-8 to a Xenopus cell-free system requiring these organelles. Caspase-8 rapidly promoted the apoptotic program, culminating in fragmentation of chromatin and the nuclear membrane. In extracts devoid of mitochondria, caspase-8 produced DNA degradation, but left nuclear membranes intact. Thus, mitochondria were required for complete engagement of the apoptotic machinery. In the absence of mitochondria, high concentrations of caspase-8 were required to activate downstream caspases. However, when mitochondria were present, the effects of low concentrations of caspase-8 were vastly amplified through cytochrome c-dependent caspase activation. Caspase-8 promoted cytochrome c release indirectly, by cleaving at least one cytosolic substrate. Bcl-2 blocked apoptosis only at the lowest caspase-8 concentrations, potentially explaining why CD95-induced apoptosis can often evade inhibition by Bcl-2.
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Smith JJ. The milled bar overdenture prosthesis. THE IMPLANT SOCIETY : [PERIODICAL] 1998; 5:12-4. [PMID: 9571836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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125
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Taylor K, Patten RD, Smith JJ, Aronovitz MJ, Wight J, Salomon RN, Konstam MA. Divergent effects of angiotensin-converting enzyme inhibition and angiotensin II-receptor antagonism on myocardial cellular proliferation and collagen deposition after myocardial infarction in rats. J Cardiovasc Pharmacol 1998; 31:654-60. [PMID: 9593063 DOI: 10.1097/00005344-199805000-00002] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
There is mechanistic rationale to suggest differential effects of angiotensin-converting enzyme (ACE) inhibition and angiotensin II type 1 (AT1)-receptor antagonism on ventricular remodeling after myocardial infarction (MI). We compared the effects of ACE inhibition, AT1-receptor antagonism, and their combination on post-MI ventricular remodeling in rats. We induced MI in 62 rats, which then received one of four treatments: (a) placebo; (b) the ACE inhibitor, enalapril; (c) the AT1-receptor antagonist, losartan; and (d) enalapril and losartan in combination. Two weeks after MI, we examined: (a) heart weight (HW)/body weight (BW) ratio; (b) nonmyocyte cellular proliferation in the noninfarct zone by using proliferating cell nuclear antigen staining; and (c) collagen content within the noninfarct zone. Placebo-treated, infarcted rats developed significant increases in HW/BW ratio (p < 0.001), left ventricular (LV) volume (p < 0.01), nonmyocyte cellular proliferation (p < 0.04), and collagen content (p < 0.01) compared with noninfarcted controls. Enalapril, losartan, and combination therapy limited the increase in HW/BW ratio (all p values <0.01 vs. placebo). Enalapril inhibited nonmyocyte proliferation (p < 0.01 vs. placebo), whereas losartan had a smaller effect (p = NS vs. placebo; p < 0.03 vs. enalapril); combined treatment also reduced nonmyocyte cellular proliferation but did not reach statistical significance (p = 0.08 vs. placebo). Enalapril and combination treatment significantly diminished collagen content (both p values <0.01 vs. placebo), whereas losartan did not. Thus, ACE inhibition and AT1-receptor antagonism equally limited myocardial hypertrophy after MI in rats, but ACE inhibition more effectively prevented nonmyocyte cellular proliferation and collagen deposition in the noninfarcted myocardium. Combination therapy was no more effective than was ACE inhibition alone. These data suggest that the myocyte hypertrophic response after MI is strongly influenced by activation of the AT1 receptor, whereas nonmyocyte cellular proliferation and collagen deposition result, in part, from mechanisms separate from AT1-receptor activation.
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