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Fleming MF, Manwell LB, Kraus M, Isaacson JH, Kahn R, Stauffacher EA. Who teaches residents about the prevention and treatment of substance use disorders? A national survey. THE JOURNAL OF FAMILY PRACTICE 1999; 48:725-729. [PMID: 10498080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
BACKGROUND Studies indicate that physicians are poorly prepared to identify and treat tobacco, alcohol, and drug use disorders. Several faculty development programs have been created to increase the number of residency teaching faculty with expertise in this area. There is limited information, however, on those who currently teach residents about these problems and whether there is a need for additional faculty development programs. METHODS We conducted a 2-stage national survey of faculty who teach residents about substance use problems. First, residency directors from 7 specialties (family medicine, psychiatry, internal medicine, pediatrics, obstetrics and gynecology, emergency medicine, and osteopathy) responded to a mailed questionnaire asking them to identify faculty who teach residents about substance use disorders. Second, those identified were contacted and asked to participate in a telephone interview. RESULTS Of 1293 faculty identified by the residency directors, 769 participated in a research interview. Most of these teachers were full-time physician faculty, men, white, and based in departments of family medicine or psychiatry. Teaching was primarily conducted in hospitals, general outpatient clinics, and classrooms rather than alcohol and drug treatment programs. Less than 10% of the faculty performed clinical work in alcohol and drug treatment programs, and only 19% were certified addiction specialists. The respondents reported a definite need for additional development programs for themselves and other residency teaching faculty. CONCLUSIONS We suggest a modest increase in the number of faculty who teach residents about substance abuse disorders, and the creation of additional faculty development programs.
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Bowen JL, Alguire P, Tran LK, Ferenchick GS, Esham R, Boulware DW, Branch WT, Kahn R, Horwitz RI. Meeting the challenges of teaching in ambulatory settings: a national, collaborative approach for internal medicine. Am J Med 1999; 107:193-7. [PMID: 10492310 DOI: 10.1016/s0002-9343(99)00227-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Sainz G, Vicat J, Kahn R, Tricot C, Stalon V, Dideberg O. Purification, crystallization and preliminary X-ray analysis of catabolic ornithine carbamoyltransferase from Pseudomonas aeruginosa. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 1999; 55:1591-3. [PMID: 10489456 DOI: 10.1107/s0907444999007970] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The catabolic ornithine carbamoyltransferase (OTCase) from Pseudomonas aeruginosa exhibits allosteric behaviour, with two conformational states of the molecule: an active R form and an inactive T form. The enzyme is a dodecamer with a molecular mass of 455700 Da. Three crystal forms have been obtained. Crystals of allosteric state T are rhombohedral, belonging to the R3 space group, with hexagonal unit-cell parameters a = b = 180.6, c = 122.0 A. They diffract to a resolution of 4.5 A. Two crystal forms for allosteric state R have been obtained, with hexagonal and cubic symmetries. Hexagonal crystals, which diffract to a resolution of 3. 4 A, belong to the space group P6(3) with unit-cell parameters a = b = 140.8, c = 145.6 A. The cubic crystals belong to space group I23, with unit-cell parameter a = 134.32 A and diffract to a resolution better than 2.5 A. In all crystal forms, the dodecamer exhibits a 23 point-group symmetry.
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Cabello-Hurtado F, Taton M, Forthoffer N, Kahn R, Bak S, Rahier A, Werck-Reichhart D. Optimized expression and catalytic properties of a wheat obtusifoliol 14alpha-demethylase (CYP51) expressed in yeast. Complementation of erg11Delta yeast mutants by plant CYP51. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 262:435-46. [PMID: 10336628 DOI: 10.1046/j.1432-1327.1999.00376.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
CYP51s form the only family of P450 proteins conserved in evolution from prokaryotes to fungi, plants and mammals. In all eukaryotes, CYP51s catalyse 14alpha-demethylation of sterols. We have recently isolated two CYP51 cDNAs from sorghum [Bak, S., Kahn, R.A., Olsen, C. E. & Halkier, B.A. (1997) Plant J. 11, 191-201] and wheat [Cabello-Hurtado, F., Zimmerlin, A., Rahier, A., Taton, M., DeRose, R., Nedelkina, S., Batard, Y., Durst, F., Pallett, K.E. & Werck-Reichhart, D. (1997) Biophys. Biochem. Res. Commun. 230, 381-385]. Wheat and sorghum CYP51 proteins show a high identity (92%) compared with their identity with their fungal and mammalian orthologues (32-39%). Data obtained with plant microsomes have previously suggested that differences in primary sequences reflect differences in sterol pathways and CYP51 substrate specificities between animals, fungi and plants. To investigate more thoroughly the properties of the plant CYP51, the wheat enzyme was expressed in yeast strains overexpressing different P450 reductases as a fusion with either yeast or plant (sorghum) membrane targeting sequences. The endogenous sterol demethylase gene (ERG11) was then disrupted. A sorghum-wheat fusion protein expressed with the Arabidopsis thaliana reductase ATR1 showed the highest level of expression and activity. The expression induced a marked proliferation of microsomal membranes so as to obtain 70 nmol P450.(L culture)-1, with CYP51 representing 1.5% of microsomal protein. Without disruption of the ERG11 gene, the expression level was fivefold reduced. CYP51 from wheat complemented the ERG11 disruption, as the modified yeasts did not need supplementation with exogenous ergosterol and grew normally under aerobic conditions. The fusion plant enzyme catalysed 14alpha-demethylation of obtusifoliol very actively (Km,app = 197 microm, kcat = 1.2 min-1) and with very strict substrate specificity. No metabolism of lanosterol and eburicol, the substrates of the fungal and mammalian CYP51s, nor metabolism of herbicides and fatty acids was detected in the recombinant yeast microsomes. Surprisingly lanosterol (Ks = 2.2 microM) and eburicol (Ks = 2.5 microm) were found to bind the active site of the plant enzyme with affinities higher than that for obtusifoliol (Ks = 289 microM), giving typical type-I spectra. The amplitudes of these spectra, however, suggested that lanosterol and eburicol were less favourably positioned to be metabolized than obtusifoliol. The recombinant enzyme was also used to test the relative binding constants of two azole compounds, LAB170250F and gamma-ketotriazole, which were previously reported to be potent inhibitors of the plant enzyme. The Ks of plant CYP51 for LAB170250F (0.29 microM) and gamma-ketotriazole (0.40 microM) calculated from the type-II sp2 nitrogen-binding spectra were in better agreement with their reported effects as plant CYP51 inhibitors than values previously determined with plant microsomes. This optimized expression system thus provides an excellent tool for detailed enzymological and mechanistic studies, and for improving the selectivity of inhibitory molecules.
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Elbahnasy A, Clayman R, Shalhav A, Hoenig D, Chandhoke P, Lingeman J, Denstedt J, Kahn R, Assimos D, Nakada S. Lower-Pole Caliceal Stone Clearance After Shockwave Lithotripsy, Percutaneous Nephrolithotomy, and Flexible Ureteroscopy: Impact of Radiographic Spatial Anatomy. J Urol 1999. [DOI: 10.1016/s0022-5347(05)69043-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Sokolov AP, Grimm H, Kahn R. Glassy dynamics in DNA: Ruled by water of hydration? J Chem Phys 1999. [DOI: 10.1063/1.478610] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
Our film Dreams and Dilemmas: Parents and the Practice of Neonatal Care is on its way to meeting its goal of furthering the "Principles for Family Centered Neonatal Care" (Harrison H. Pediatrics 1993;92:643-50) through cinéma vérité depiction of parental involvement in decision-making. Reality-based filmmaking can provide valuable and successful educational material that advances care and understanding. However, there are real practical and ethical concerns such as privacy, consent, and uncertain or unknown future impact on participants. Successful reality-based filmmaking in a complex medical environment such as a neonatal intensive care unit requires careful attention to ways of ensuring full communication between all those involved and efforts to allay participants' anxiety about being portrayed unfavorably. The most important ingredient, however, is the skill and ability of the filmmaker to engender trust.
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Rosenberg D, Moseley K, Kahn R, Kissinger P, Rice J, Kendall C, Coughlin S, Farley TA. Networks of persons with syphilis and at risk for syphilis in Louisiana: evidence of core transmitters. Sex Transm Dis 1999; 26:108-14. [PMID: 10029986 DOI: 10.1097/00007435-199902000-00009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND AND OBJECTIVES Differences in sociodemographic attributes and healthcare access may explain differences in regional sexually transmitted disease rates but don't fully explain why syphilis persists disproportionately in certain populations. GOAL OF THIS STUDY To understand the behavioral epidemiology of syphilis, we conducted a social network analysis of persons with syphilis and their contacts and developed and applied a definition of core transmitters. STUDY DESIGN We interviewed 10 index persons with primary or secondary untreated syphilis and 80 of their named sexual and social contacts. RESULTS Fourteen (16%) of 90 interviewed persons met the definition of core transmitters, 9 of whom had past or current syphilis. The other interviewed persons had only moderately risky behaviors. Seventy-eight (42%) of the network sexual contacts were connected directly or indirectly to a core transmitter. CONCLUSION This analysis suggests that syphilis transmission is maintained by a community with a small percentage of high-risk persons centrally placed amidst a larger group with moderately risky behavior.
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Andersen AB, Ravn P, Kahn R, Rosted A, Philipsen EK. Hepatic actinomycosis. A case report. APMIS 1999; 107:225-30. [PMID: 10225321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
A case of hepatic actinomycosis contracted one year after removal of an intrauterine device during ongoing Actinomyces cervicitis is reported. During active disease, lymphocytes from the apparently fully immunocompetent patient were able to proliferate but not to produce the proinflammatory lymphokine gamma-interferon in response to Actinomyces antigen. This ability was only partly restored during antibiotic therapy.
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Ramin M, Shepard W, Fourme R, Kahn R. Multiwavelength anomalous solvent contrast (MASC): derivation of envelope structure-factor amplitudes and comparison with model values. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 1999; 55:157-67. [PMID: 10089406 DOI: 10.1107/s090744499800626x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/1998] [Accepted: 04/30/1998] [Indexed: 11/10/2022]
Abstract
A previous article [Fourme et al. (1995). J. Synchrotron Rad. 2, 36-48] presented the theoretical foundations of MASC, a new contrast-variation method using multiwavelength anomalous scattering, and reported the first experimental results. New experiments have been conducted both at the ESRF (Grenoble, France) and at LURE-DCI (Orsay, France), using cryocooled crystals of three proteins of known structures and very different molecular weights. Amplitudes of {GammaT(h)}, the 'normal' structure factors of the anomalously scattering part of the crystal including the solvent zone and the ordered anomalous scattering sites (if any), have been extracted from multiwavelength data. In the very low resolution range (d >/= 20 A), the agreement between experimental {GammaT(h)} and model values calculated from the bulk solvent is all the more satisfactory since the molecular weight of the protein is high. For spacings between 10 and 20 A, the agreement between experimental {GammaT(h)} and model values is also satisfactory if one takes into account ordered anomalous scatterer sites. Such sites have been found in the three cases.
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Marin ML, Parsons RE, Hollier LH, Mitty HA, Ahn J, Parsons RE, Temudom T, D'Ayala M, McLaughlin M, DePalo L, Kahn R. Impact of transrenal aortic endograft placement on endovascular graft repair of abdominal aortic aneurysms. J Vasc Surg 1998; 28:638-46. [PMID: 9786258 DOI: 10.1016/s0741-5214(98)70088-6] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
PURPOSE Successful endovascular repair of an abdominal aortic aneurysm (AAA) requires the creation of a hemostatic seal between the endograft and the underlying aortic wall. A short infrarenal aortic neck may be responsible for incomplete aneurysm exclusion and procedural failure. Sixteen patients who had an endograft positioned completely below the lowest renal artery and 37 patients in whom a porous portion of an endograft attachment system was deliberately placed across the renal arteries were studied to identify if endograft positioning could impact on the occurrence of incomplete aneurysm exclusion. METHODS Fifty-three patients underwent aortic grafting constructed from a Palmaz balloon expandable stent and an expandable polytetrafluoroethylene (ePTFE) graft implanted in an aorto-ilio-femoral, femoral-femoral configuration. Arteriography, duplex ultrasonography and spiral CT scans were performed in each patient before and after endografting to evaluate for technical success, the presence of endoleaks, and renal artery perfusion. RESULTS There was no statistically significant difference in patient demography, AAA size, or aortic neck length or diameter between patients who had their endografts placed below or across the renal arteries. However, significantly more proximal aortic endoleaks occurred in those patients with infrarenal endografts (P < or = .05). Median serum creatinine level before and after endografting was not significantly different between the 2 patient subgroups, with the exception of 2 patients who had inadvertent coverage of a single renal orifice by the endograft. Median blood pressure and the requirement for antihypertensive therapy remained the same after transrenal aortic stent grafting. Significant renal artery compromise did not occur after appropriately positioned transrenal stents as shown by means of angiography, CT scanning, and duplex ultrasound scan. Mean follow-up time was 10.3 months (range, 3 to 18 months). Patients who had significant renal artery stenosis (> or =50%) before aortic endografting did not show progression of renal artery stenosis after trans-renal endografting. Two patients with transrenal aortic stent grafts had inadvertent coverage of 1 renal artery by the endograft because of device malpositioning, which resulted in nondialysis dependent renal insufficiency. In addition, evidence of segmental renal artery infarction (<20% of the kidney), which did not result in an apparent change in renal function, was shown by means of follow-up CT scans in 2 patients with transrenal endografts. CONCLUSION Transrenal aortic endograft fixation using a balloon expandable device in patients with AAAs can result in a significant reduction in the risk of proximal endoleaks. Absolute attention to precise device positioning, coupled with the use of detailed imaging techniques, should reduce the risk of inadvertent renal artery occlusion from malpositioning. Long-term follow-up is essential to determine if there will be late sequelae of transrenal fixation of endografts, which could adversely effect renal perfusion.
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Elbahnasy AM, Clayman RV, Shalhav AL, Hoenig DM, Chandhoke P, Lingeman JE, Denstedt JD, Kahn R, Assimos DG, Nakada SY. Lower-pole caliceal stone clearance after shockwave lithotripsy, percutaneous nephrolithotomy, and flexible ureteroscopy: impact of radiographic spatial anatomy. J Endourol 1998. [PMID: 9607435 DOI: 10.1016/s0022-5347(01)63699-1] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Spatial anatomy of the lower renal pole, as defined by the infundibulopelvic angle (LIP angle), infundibular length (IL), and infundibular width (IW), plays a significant role in the stone-free rate after shockwave lithotripsy. A wide LIP angle, a short IL, and a broad IW, individually or in combination, favor stone clearance, whereas a LIP <70 degrees, an IL >3 cm, or an IW < or =5 mm are individually unfavorable. When all three unfavorable factors or an unfavorable LIP and IL coexist, the post-SWL stone-free rate falls to 50% or less. Using these criteria, more than one fourth of our patients with a lower-pole calculus might have been better served by an initial percutaneous or perhaps ureteroscopic procedure, neither of which is significantly affected by the lower-pole spatial anatomy.
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Wakatsuki S, Belrhali H, Mitchell EP, Burmeister WP, McSweeney SM, Kahn R, Bourgeois D, Yao M, Tomizaki T, Theveneau P. ID14 'Quadriga', a Beamline for Protein Crystallography at the ESRF. JOURNAL OF SYNCHROTRON RADIATION 1998; 5:215-221. [PMID: 15263481 DOI: 10.1107/s0909049597018785] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/1997] [Accepted: 12/05/1997] [Indexed: 05/24/2023]
Abstract
The ESRF undulator beamline ID14 'Quadriga' is dedicated to monochromatic macromolecular crystallography. Using two undulators with 23 mm and 42 mm periods and a minimum gap of 16 mm installed on a high-beta section, it will provide high-brilliance X-ray beams at around 13.5 keV, as well as a wide tuneability between 6.8 and 40 keV. Based on the Troika concept, this beamline has four simultaneously operating experimental stations: three side stations, EH1, EH2 and EH3, using thin diamond crystals, and an end station, EH4, with a fast-scan double-crystal monochromator. Station EH3 has a kappa-diffractometer, and an off-line Weissenberg camera with a large 80 x 80 cm active area combined with a 2048 x 2048 CCD detector. During data collection the image plates are placed and removed by a robot located inside the hutch using a cassette system. After data collection the image plates are scanned with an off-line drum scanner. Station EH4 is designed for MAD applications, including Xe K-edge anomalous experiments, and is equipped with a 2048 x 2048 CCD detector on a pseudo 2theta arm. A common graphical user interface and a database will be available to cover all aspects of data collection, including strategy optimization. First results on the performance of the optics elements and initial crystallographic results are presented.
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Besenböck W, Gähler R, Hank P, Kahn R, Köppe M, De Novion CH, Petry W, Wuttke J. First scattering experiment on MIEZE: A fourier transform time-of-flight spectrometer using resonance coils. JOURNAL OF NEUTRON RESEARCH 1998. [DOI: 10.1080/10238169808200231] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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115
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Elbahnasy AM, Clayman RV, Shalhav AL, Hoenig DM, Chandhoke P, Lingeman JE, Denstedt JD, Kahn R, Assimos DG, Nakada SY. Lower-pole caliceal stone clearance after shockwave lithotripsy, percutaneous nephrolithotomy, and flexible ureteroscopy: impact of radiographic spatial anatomy. J Endourol 1998; 12:113-9. [PMID: 9607435 DOI: 10.1089/end.1998.12.113] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Spatial anatomy of the lower renal pole, as defined by the infundibulopelvic angle (LIP angle), infundibular length (IL), and infundibular width (IW), plays a significant role in the stone-free rate after shockwave lithotripsy. A wide LIP angle, a short IL, and a broad IW, individually or in combination, favor stone clearance, whereas a LIP <70 degrees, an IL >3 cm, or an IW < or =5 mm are individually unfavorable. When all three unfavorable factors or an unfavorable LIP and IL coexist, the post-SWL stone-free rate falls to 50% or less. Using these criteria, more than one fourth of our patients with a lower-pole calculus might have been better served by an initial percutaneous or perhaps ureteroscopic procedure, neither of which is significantly affected by the lower-pole spatial anatomy.
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116
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Selten JP, Slaets J, Kahn R. Prenatal exposure to influenza and schizophrenia in Surinamese and Dutch Antillean immigrants to The Netherlands. Schizophr Res 1998; 30:101-3. [PMID: 9542793 DOI: 10.1016/s0920-9964(97)00105-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
There is evidence of an increased incidence of schizophrenia in Afro-Caribbean immigrants to the UK and in Surinamese- and Dutch Antillean immigrants to The Netherlands. We tested the hypothesis that second-trimester exposure to the 1957 A2 influenza pandemic, which swept through the Caribbean in the same period as it affected Western Europe, contributes to this phenomenon. The dates of birth of immigrants, discharged from a Dutch psychiatric institute with a diagnosis of schizophrenia, were examined for any effect of the pandemic. Individuals who were in their second-trimester of fetal life at the peak of the pandemic were at no greater risk of developing schizophrenia than controls.
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Bederson JB, Levy AL, Ding WH, Kahn R, DiPerna CA, Jenkins AL, Vallabhajosyula P. Acute vasoconstriction after subarachnoid hemorrhage. Neurosurgery 1998; 42:352-60; discussion 360-2. [PMID: 9482187 DOI: 10.1097/00006123-199802000-00091] [Citation(s) in RCA: 231] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE Decreased cerebral blood flow (CBF) and cerebral ischemia occurring immediately after subarachnoid hemorrhage (SAH) may be caused by acute microvascular constriction. However, CBF can also be influenced by changes in intracranial pressure (ICP) and cerebral perfusion pressure (CPP). The goal of these experiments was to assess the significance of acute vasoconstriction after SAH and its relationship to changes in CBF, ICP, CPP, and extracellular glutamate concentrations. METHODS Three experiments were performed using the endovascular filament technique to produce SAH. In the first experiment, CBF, ICP, and CPP were measured for 60 minutes after SAH (n = 21) and were correlated with the 24-hour mortality rate. In the second experiment, rats undergoing SAH (n = 23) or a sham procedure (n = 7) were perfused 60 minutes after SAH for measurement of the circumference and wall thickness of the internal carotid and anterior cerebral arteries and correlation with CBF, ICP, and CPP. In the third experiment (n = 11), extracellular glutamate concentrations determined by hippocampal and cortical microdialysis and high performance liquid chromatography were correlated with physiological changes. RESULTS CBF reductions to less than 40% of baseline for 60 minutes after SAH predicted 24-hour mortality with 100% accuracy and were used to define "lethal" SAH. In contrast, ICP and CPP 60 minutes after SAH were not correlated with the mortality rate. The vascular circumference was significantly smaller in lethal than in sublethal SAH or sham-operated rats (P < 0.001). Vessel measurements were correlated with both CBF and hemorrhage size (P < 0.01). Extracellular glutamate concentration increased to 600% of baseline after lethal SAH in both hippocampus and cortex and was inversely correlated with CBF (r = 0.9, P < 0.001) but did not increase after sublethal SAH. CONCLUSION Acute vasoconstriction after SAH occurs independently of changes in ICP and CPP and is associated with decreased CBF, larger hemorrhage size, persistent elevations of extracellular glutamate, and poor outcome. Acute vasoconstriction seems to contribute directly to ischemic brain injury after SAH. Further evaluations of pharmacological agents with the potential to reverse acute vasoconstriction may increase CBF and improve outcome.
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Bourgeois D, Nurizzo D, Kahn R, Cambillau C. An Integration Routine Based on Profile Fitting with Optimized Fitting Area for the Evaluation of Weak and/or Overlapped Two-Dimensional Laue or Monochromatic Patterns. J Appl Crystallogr 1998. [DOI: 10.1107/s0021889897006730] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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119
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Kahn R. Nickel should be on the list of toxins introduced to food through cookware. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 1998; 98:16. [PMID: 9434643 DOI: 10.1016/s0002-8223(98)00004-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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120
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Joyner L, McNeeley S, Kahn R. ADA's (American Diabetes Association) provider recognition program. HMO PRACTICE 1997; 11:168-70. [PMID: 10176518] [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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121
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Therbo M, Nielsen JK, Pallesen P, Kahn R. [Cervical extraosseous Ewing sarcoma]. Ugeskr Laeger 1997; 159:6686-7. [PMID: 9411985] [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]
Abstract
A case of extraosseous Ewing's sarcoma is presented. The clinical, morphological and imaging characteristics of this rare neoplasm are briefly discussed.
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Kahn R. Physician responsibility and accountability. Future legislation may clarify issues. MICHIGAN MEDICINE 1997; 96:30. [PMID: 9348744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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123
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Schiltz M, Kvick A, Svensson OS, Shepard W, de La Fortelle E, Prangé T, Kahn R, Bricogne G, Fourme R. Protein Crystallography at Ultra-Short Wavelengths: Feasibility Study of Anomalous-Dispersion Experiments at the Xenon K-edge. JOURNAL OF SYNCHROTRON RADIATION 1997; 4:287-97. [PMID: 16699242 DOI: 10.1107/s0909049597008571] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
A protein crystallography experiment at the xenon K-edge (lambda = 0.358 A) has been successfully carried out at the materials science beamline (BL2/ID11) of the ESRF. The samples used in this methodological study were crystals of porcine pancreatic elastase, a 26 kDa protein of known structure. The diffraction data are of excellent quality. The combination of isomorphous replacement and anomalous dispersion of a single xenon heavy-atom derivative allowed accurate phase determination and the computation of a high-quality electron density map of the protein molecule. This is the first fully documented report on a complete protein crystallography experiment, from data collection up to phase determination and calculation of an electron density map, carried out with data obtained at ultra-short wavelengths. Experimental considerations as well as possible advantages and drawbacks of protein crystallography at very short and ultra-short wavelengths are discussed.
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Abstract
OBJECTIVE Switching from two-lung to one-lung ventilation would be expected to have large effects on lung mechanical properties, and these effects may depend on tidal volume and respiratory frequency. These changes in lung mechanics with one-lung ventilation may be similar to pulmonary edema. Deteriorating lung mechanics during pulmonary edema have been attributed to a loss of ventilated lung units. Therefore, changes in lung mechanics caused by one-lung ventilation were measured and compared with those previously seen during pulmonary edema. DESIGN Prospective study. SETTING Research laboratory. INTERVENTIONS After induction of anesthesia, beagle dogs' tracheas were intubated with an endotracheal tube with a bronchial blocker (Univent System Corp, Tokyo, Japan) to apply one-lung ventilation. The proper position of the bronchial blocker during one-lung ventilation was confirmed with a fiberoptic bronchoscope. MEASUREMENTS AND MAIN RESULTS Lung elastance (EL) and resistance (RL) were calculated from measurements of airway pressure, esophageal pressure, and airway flow in five anesthetized, paralyzed dogs during sinusoidal forcing at a constant mean airway pressure of 10 cmH2O in a wide range of breathing frequencies (0.2 to 1.0 Hz in intervals of 0.2) and tidal volumes (50, 100, 200, and to 300 mL). Measurements were made before and after the left mainstem bronchus was occluded with the bronchial blocker. During ventilation of both lungs, EL and RL depended relatively little on frequency, and both EL and RL were independent of tidal volume. During one-lung ventilation, EL doubled and, at most frequencies, RL increased; frequency dependences were not increased, and no dependence on tidal volume was observed. CONCLUSIONS The lack of tidal volume dependence in EL and lack of large-frequency dependence in RL during one-lung ventilation are inconsistent with changes induced by severe pulmonary edema. Although decreases in ventilatable lung volume may contribute to increases in lung elastance, other characteristics of mechanical behavior during one-lung ventilation differ from those of pulmonary edema; therefore, other additional mechanisms must be involved in determining lung mechanical properties during severe pulmonary edema.
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Barnas GM, Delaney PA, Gheorghiu I, Mandava S, Russell RG, Kahn R, Mackenzie CF. Respiratory impedances and acinar gas transfer in a canine model for emphysema. J Appl Physiol (1985) 1997; 83:179-88. [PMID: 9216962 DOI: 10.1152/jappl.1997.83.1.179] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We examined how the changes in the acini caused by emphysema affected gas transfer out of the acinus (Taci) and lung and chest wall mechanical properties. Measurements were taken from five dogs before and 3 mo after induction of severe bilateral emphysema by exposure to papain aerosol (170-350 mg/dose) for 4 consecutive wk. With the dogs anesthetized, paralyzed, and mechanically ventilated at 0.2 Hz and 20 ml/kg, we measured Taci by the rate of washout of 133Xe from an area of the lung with occluded blood flow. Measurements were repeated at positive end-expiratory pressures (PEEP) of 10, 5, 15, 0, and 20 cmH2O. We also measured dynamic elastances and resistances of the lungs (EL and RL, respectively) and chest wall at the different PEEP and during sinusoidal forcing in the normal range of breathing frequency and tidal volume. After final measurements, tissue sections from five randomly selected areas of the lung each showed indications of emphysema. Taci during emphysema was similar to that in control dogs. EL decreased by approximately 50% during emphysema (P < 0.05) but did not change its dependence on frequency or tidal volume. RL did not change (P > 0.05) at the lowest frequency studied (0.2 Hz), but in some dogs it increased compared with control at the higher frequencies. Chest wall properties were not changed by emphysema (P > 0.05). We suggest that although large changes in acinar structure and EL occur during uncomplicated bilateral emphysema, secondary complications must be present to cause several of the characteristic dysfunctions seen in patients with emphysema.
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