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Owens DR, Bothner B, Phung Q, Harris K, Siuzdak G. Aspects of oligonucleotide and peptide sequencing with MALDI and electrospray mass spectrometry. Bioorg Med Chem 1998; 6:1547-54. [PMID: 9801826 DOI: 10.1016/s0968-0896(98)00098-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Biopolymer sequencing with mass spectrometry has become increasingly important and accessible with the development of matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI). Here we examine the use of sequential digestion for the rapid identification of proteolytic fragments, in turn highlighting the general utility of enzymatic MALDI ladder sequencing and ESI tandem mass spectrometry. Analyses were performed on oligonucleotides ranging in size from 2 to 50 residues, on peptides ranging in size from 7 to 44 residues and on viral coat proteins. MALDI ladder sequencing using exonuclease digestion generated a uniform distribution of ions and provided complete sequence information on the oligonucleotides 2-30 nucleic acid residues long. Only partial sequence information was obtained on the longer oligonucleotides. C-terminal peptide ladder sequencing typically provided information from 4 to 7 amino acids into the peptide. Sequential digestion, or endoprotease followed by exoprotease exposure, was also successfully applied to a trypsin digest of viral proteins. Analysis of ladder sequenced peptides by LCMS generated less information than in the MALDI-MS analysis and ESI-MS2 normally provided partial sequence information on both the small oligonucleotides and peptides. In general, MALDI ladder sequencing offered information on a broader mass range of biopolymers than ESI-MS2 and was relatively straightforward to interpret, especially for oligonucleotides.
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Ellison MD, Hung RT, Harris K, Campbell BH. Report of the first case of invasive fungal sinusitis caused by Scopulariopsis acremonium: review of scopulariopsis infections. ARCHIVES OF OTOLARYNGOLOGY--HEAD & NECK SURGERY 1998; 124:1014-6. [PMID: 9738812 DOI: 10.1001/archotol.124.9.1014] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Scopulariopsis acremonium is a species of saprophytic fungus not previously reported to cause invasive disease in humans, although invasive infections from other species of Scopulariopsis have been reported and are reviewed. Deep infection with this fungus is associated with a high mortality rate. Invasive fungal sinusitis, in general, is a potentially fatal disease that typically affects immunocompromised patients, such as those receiving intensive chemotherapy or undergoing bone marrow transplantation. We report a case of invasive fungal sinusitis caused by Scopulariopsis acremonium in a patient with leukemia, who was successfully treated with amphotericin B, itraconazole, endoscopic sinus surgery, and granulocyte colony-stimulating factor.
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Sorra KE, Fiala JC, Harris KM. Critical assessment of the involvement of perforations, spinules, and spine branching in hippocampal synapse formation. J Comp Neurol 1998; 398:225-40. [PMID: 9700568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Several studies propose that long-term enhancement of synaptic transmission between neurons results from the enlargement, perforation, and splitting of synapses and dendritic spines. Unbiased analyses through serial electron microscopy were used to assess the morphological basis for synapse spilitting in hippocampal area CA1. Few perforated synapses and almost no split (i.e., branched) spines occurred at postnatal day 15, an age of high synaptogenesis; thus, synapse splitting is unlikely to be important during development. The synapse splitting hypothesis predicts an intermediate stage of branched spines with both heads sharing the same presynaptic bouton. Ninety-one branched dendritic spines were traced through serial sections, and the different branches never synapsed with the same presynaptic bouton. Projections from spines, called "spinules," have been thought to extend from perforations in the postsynaptic density (PSD), thereby dividing the presynaptic bouton. Forty-six spinules were traced, and only 13% emerged from perforations in the PSD. Most spinules emerged from the edges of nonperforated PSDs, or from spine necks, where they extended into boutons that were not presynaptic to the spine. In summary, these morphological characteristics are inconsistent with synapse and spine splitting. An alternative is discussed whereby perforated synapses and spinules are transient components of synaptic activation, and branched spines appear from synapses forming in close proximity to one another.
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Khattak FH, Morris IM, Harris K. Kelley-Seegmiller syndrome: a case report and review of the literature. BRITISH JOURNAL OF RHEUMATOLOGY 1998; 37:580-1. [PMID: 9651092 DOI: 10.1093/rheumatology/37.5.580c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Baker RE, Harris K, Zhang K. Mutations synthetically lethal with cep1 target S. cerevisiae kinetochore components. Genetics 1998; 149:73-85. [PMID: 9584087 PMCID: PMC1460145 DOI: 10.1093/genetics/149.1.73] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
CP1 (encoded by CEP1) is a Saccharomyces cerevisiae chromatin protein that binds a DNA element conserved in centromeres and in the 5'-flanking DNA of methionine biosynthetic (MET) genes. Strains lacking CP1 are defective in chromosome segregation and MET gene transcription, leading to the hypothesis that CP1 plays a general role in assembling higher order chromatin structures at genomic sites where it is bound. A screen for mutations synthetically lethal with a cep1 null allele yielded five recessive csl (cep1 synthetic lethal) mutations, each defining a unique complementation group. Four of the five mutations synergistically increased the loss rate of marker chromosomes carrying a centromere lacking the CP1 binding site, suggesting that the cep1 synthetic lethality was due to chromosome segregation defects. Three of these four CSL genes were subsequently found to be known or imputed kinetochore genes: CEP3, NDC10, and CSE4. The fourth, CSL4, corresponded to ORF YNL232w on chromosome XIV, and was found to be essential. A human cDNA was identified that encoded a protein homologous to Csl4 and that complemented the csl4-1 mutation. The results are consistent with the view that the major cellular role of CP1 is to safeguard the biochemical integrity of the kinetochore.
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Harris KM, Furstenberg FF, Marmer JK. Paternal involvement with adolescents in intact families: the influence of fathers over the life course. Demography 1998; 35:201-16. [PMID: 9622782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We measure the quality and quantity of fathers' involvement with adolescent children in intact families over time using longitudinal data from The National Survey of Children. We examine differentials in fathers' involvement by children's and family characteristics and model the long-term effects of fathers' involvement on children's outcomes in the transition to adulthood. Fathers are more involved with sons than with daughters and they disengage from adolescents with increasing marital conflict. We find beneficial effects for children of father's involvement in three domains: educational and economic attainment, delinquent behavior, and psychological well-being. The course of affective relations throughout adolescence also has a beneficial effect on delinquent behavior and psychological well-being.
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Lee R, Nitta T, Schmid RA, Schuessler RB, Harris KM, Gay WA. Retrograde infusion of lidocaine or L-arginine before reperfusion reduces myocardial infarct size. Ann Thorac Surg 1998; 65:1353-9. [PMID: 9594866 DOI: 10.1016/s0003-4975(98)00186-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Retrograde perfusion preserves ischemic myocardium when initiated shortly after coronary artery occlusion. However, benefits diminish as the delay increases. In this study, we used this technique to deliver agents known to reduce the injury associated with the reperfusion of ischemic myocardium. We proposed that the local delivery of lidocaine or L-arginine before reperfusion would reduce the damage caused during reperfusion, even after a delay between onset of ischemia and intervention designed to approximate clinical reality. METHODS In a porcine model of myocardial ischemia, the left anterior descending coronary artery was snared immediately distal to its second diagonal branch. After 1 hour of occlusion, 34 animals were randomized into six groups: no intervention (control) (n = 6); administration of normal saline solution into the great cardiac vein (Retro-NS) (n = 6); administration of lidocaine either intravenously (i.v.-LID) (n = 6) or retrograde (Retro-LID) (n = 6); and administration of L-arginine either intravenously (i.v.-L-ARG) (n = 5) or retrograde (Retro-L-ARG) (n = 5). After 90 minutes of ischemia, the snare was released, and the myocardium was reperfused for 3 hours. Two-dimensional echocardiograms were made prior to occlusion and 60, 150, 210, and 270 minutes after occlusion. The infarct size and the area at risk were determined by lissamine green and triphenyltetrazolium chloride staining with computer planimetric quantification. Regional wall motion was assessed by a wall motion score: normal = 1; mild hypokinesia = 2.0; severe hypokinesia = 2.5; and akinesia = 3. RESULTS The area of the left ventricle at risk for infarction was similar in all groups and represented 25.4% (5.2% [standard deviation]) of the left ventricular mass (p = 0.63). The percent area of infarction in the area at risk after 3 hours of reperfusion was 76.7% (7.1% for the control group, 73.9% (5.7%) for the Retro-NS group, 72.1% (8.7%) for the i.v.-LID group, 54.5% (10.2%) for the Retro-LID group, 58.8% (4.0%) for the i.v.-L-ARG group, and 54.3% (4.0%) for the Retro-L-ARG group p < 0.005, Retro-LID and Retro-L-ARG versus Control, Retro-NS, and i.v.-LID; p < 0.03, i.v.-L-ARG versus control and Retro-NS). No significant difference in wall motion scores between groups was detected by echocardiography (p = 0.578). CONCLUSIONS Retrograde delivery of lidocaine or L-arginine before reperfusion reduces infarct size without acutely affecting wall motion after 90 minutes of ischemia and 3 hours of reperfusion. Lidocaine must be present before reperfusion to have an effect, whereas L-arginine is beneficial if it is delivered at the time of reperfusion.
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Spacek J, Harris KM. Three-dimensional organization of cell adhesion junctions at synapses and dendritic spines in area CA1 of the rat hippocampus. J Comp Neurol 1998; 393:58-68. [PMID: 9520101 DOI: 10.1002/(sici)1096-9861(19980330)393:1<58::aid-cne6>3.0.co;2-p] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Recent work has emphasized the role of adhesion molecules in synaptic plasticity, including long-term potentiation in the hippocampus. Such adhesion molecules are concentrated in junctions that are characterized by dense thickenings on both sides of the junction and are called puncta adhaerentia (PA). Reconstruction from serial electron microscopy was used to determine the location and size of PA in the stratum radiatum of hippocampal area CA1, where many of the previous functional studies have been performed. PAs were found at the edges of synapses on 33% of dendritic spines. The areas occupied by PA were variable across different types of synapses, occupying 0.010+/-0.005 microm2 at macular synapses and 0.034+/-0.031 microm2 at perforated synapses. Another zone, called a vesicle-free transition zone (VFTZ), was identified. Like the PA, this zone also had no presynaptic vesicles and was located at the edges of synapses; however, unlike the PA, the presynaptic thickening was less than the postsynaptic thickening. Together, 45% of spine synapses had PA and/or VFTZ occupying 23+/-11% of the total junctional area between axons and spines. PA also occurred at nonsynaptic sites involving neuronal as well as glial elements. Most (64%) of these PAs occurred between nonsynaptic portions of dendritic spines and neighboring astrocytic processes. Smooth endoplasmic reticulum was often apposed to one or both sides of the synaptic and the nonsynaptic PA. These findings provide further data as a structural basis for understanding the roles of cell adhesion junctions in hippocampal synaptic function and plasticity.
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Lopez H, Harris KM. Ultrasound interactions with free silicone in a tissue-mimicking phantom. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 1998; 17:163-170. [PMID: 9514168 DOI: 10.7863/jum.1998.17.3.163] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This study attempts to explain the physical basis for the sonographic appearance of different stages of free silicone in breast tissue by laboratory simulations. A tissue-mimicking breast phantom was constructed, into which silicone inclusions were introduced, to simulate various forms of silicone leakage within the body. These simulations suggest that silicone leakage into surrounding body tissues can cause three primary physical interactions with an ultrasound beam: (1) distortions due to changes in speed of sound; (2) refraction, causing a "lens" effect; and (3) multiple scattering, producing the "snowstorm" effect described previously as a signature pattern for detection of silicone migration in breast tissue.
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Shaw CC, Wang T, King JL, Breitenstein DS, Chang TS, Harris KM, Baratz AB, Ganott MA, Reginella R, Sumkin JH, Gur D. Computed radiography versus screen-film mammography in detection of simulated microcalcifications: a receiver operating characteristic study based on phantom images. Acad Radiol 1998; 5:173-80. [PMID: 9522883 DOI: 10.1016/s1076-6332(98)80281-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
RATIONALE AND OBJECTIVES The authors compare a 43-micron computed radiographic system with a mammographic screen-film system for detection of simulated microcalcifications in an observer-performance study. MATERIALS AND METHODS The task of detecting microcalcifications was simulated by imaging aluminum wire segments (200-500 microns in length; 100, 125, or 150 microns in diameter) that overlapped with tissue background structures produced by beef brisket. A total of 288 such simulations were generated and examined with both computed radiography and conventional screen-film mammography techniques. Computed radiography was performed with high-resolution plates, a 43-micron image reader, and a 43-micron laser film printer. Computed radiographic images were printed with simple contrast enhancement and compared with screen-film images in a receiver operating characteristic study in which experienced readers detected and scored the simulated microcalcifications. Observer performance was quantitated and compared by computing the area under the receiver operating characteristic curve. RESULTS Although the resolution of the computed radiography system was better than that of commercial systems, it fell short of that of screen-film systems. For the 100-micron microcalcifications, the difference in the average area under the curve was not statistically significant, but it was significant for the larger simulated microcalcifications: the average area under the curve was 0.58 for computed radiography versus 0.76 for screen-film imaging for the 125-micron microcalcifications and 0.83 versus 1.00, respectively, for the 150-micron microcalcifications. CONCLUSION Observer performance in the detection of small simulated microcalcifications (100-150 microns in diameter) is better with screen-film images than with high-resolution computed radiographic images.
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Sorra KE, Harris KM. Stability in synapse number and size at 2 hr after long-term potentiation in hippocampal area CA1. J Neurosci 1998; 18:658-71. [PMID: 9425008 PMCID: PMC6792539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Long-term potentiation (LTP) is an important model for examining synaptic mechanisms of learning and memory. A key question is whether the enhanced synaptic transmission occurring with LTP involves the addition of new synapses, the enlargement of existing synapses, or a redistribution in synaptic weight among synapses. Two experimental designs were used to address this question. In the first experimental design three conditions were evaluated across hippocampal slices maintained in vitro, including slices with LTP analyzed at 2 hr post-tetanus, slices tetanized in the presence of APV, and control slices receiving test stimulation only. In the second experimental design independent LTP and control (low-frequency stimulation) sites were examined. Synapse density was estimated by an unbiased volume sampling procedure. Synapse size was computed by three-dimensional reconstruction from serial electron microscopy (EM). Serial EM also was used to compute synapse number per unit length of dendrite. In both experimental designs there were no significant effects of LTP on total synapse number, on the distribution of different types of synapses (thin, mushroom, stubby, or branched dendritic spines and macular, perforated, or segmented postsynaptic densities), on the frequency of shaft synapses, nor on the relative proportion of single or multiple synapse axonal boutons. There was also no increase in synapse size. These results suggest that LTP does not cause an overall formation of new synapses nor an enlargement of synapses at 2 hr post-tetanus in hippocampal area CA1, and these results support the hypothesis that LTP could involve a redistribution of synaptic weights among existing synapses.
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Sumkin JH, Perrone AM, Harris KM, Nath ME, Amortegui AJ, Weinstein BJ. Lactating adenoma: US features and literature review. Radiology 1998; 206:271-4. [PMID: 9423682 DOI: 10.1148/radiology.206.1.9423682] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PURPOSE To describe the ultrasonographic (US) features of adenoma in a lactating breast. MATERIALS AND METHODS The US scans of 11 lactating adenomas in nine patients aged 25-36 years examined in 1991-1996 were retrospectively reviewed. In all lesions, diagnoses were cytologically or histologically proved after US-guided fine-needle aspiration biopsy (eight lesions) or core biopsy (three lesions). Six patients were lactating, and three patients were in the third trimester of pregnancy. The US features analyzed were shape, orientation to the chest wall, border characteristics, echogenicity, homogeneity, enhancement or shadowing, and depth within the breast. RESULTS Most lesions had benign US features such as ovoid shape with the long axis parallel to the chest wall (10 of 11), well-defined margins (eight of 11), homogeneous echotexture (eight of 11), and posterior acoustic enhancement (10 of 11). Four lesions had US features that resembled malignant lesions, such as irregular margins, heterogeneous echotexture, and posterior acoustic shadowing. CONCLUSION The US features, although generally benign, are not specific. Tissue sampling with fine-needle aspiration biopsy is recommended. Core biopsy is necessary if a diagnosis cannot be made with the aspirate but is not performed initially because of the possibility of milk fistula formation.
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Rauch U, Badimon J, Vorchheimer D, Guzman I, Harris K, Harris P, Sandler D, Fallon J, Fuster V, Chosebro J. Lipid lowering therapy reduces blood thrombogenicity in hypercholesterolemic patients: effect of simvastatin. J Am Coll Cardiol 1998. [DOI: 10.1016/s0735-1097(98)81482-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Harris K. What works. Automated time and payroll system replaces paper time sheets. HEALTH MANAGEMENT TECHNOLOGY 1997; 18:34. [PMID: 10175214] [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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Finkbeiner S, Tavazoie SF, Maloratsky A, Jacobs KM, Harris KM, Greenberg ME. CREB: a major mediator of neuronal neurotrophin responses. Neuron 1997; 19:1031-47. [PMID: 9390517 DOI: 10.1016/s0896-6273(00)80395-5] [Citation(s) in RCA: 733] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Neurotrophins regulate neuronal survival, differentiation, and synaptic function. To understand how neurotrophins elicit such diverse responses, we elucidated signaling pathways by which brain-derived neurotrophic factor (BDNF) activates gene expression in cultured neurons and hippocampal slices. We found, unexpectedly, that the transcription factor cyclic AMP response element-binding protein (CREB) is an important regulator of BDNF-induced gene expression. Exposure of neurons to BDNF stimulates CREB phosphorylation and activation via at least two signaling pathways: by a calcium/calmodulin-dependent kinase IV (CaMKIV)-regulated pathway that is activated by the release of intracellular calcium and by a Ras-dependent pathway. These findings reveal a previously unrecognized, CaMK-dependent mechanism by which neurotrophins activate CREB and suggest that CREB plays a central role in mediating neurotrophin responses in neurons.
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Harris K. If I can do it anyone can. West J Med 1997. [DOI: 10.1136/bmj.315.7115.1100b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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192
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Harris K. Flexible pricing for CCRCs. CONTEMPORARY LONGTERM CARE 1997; 20:49-50. [PMID: 10174853] [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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Harris KM, Braverman AC, Gutierrez FR, Barzilai B, Dávila-Román VG. Transesophageal echocardiographic and clinical features of aortic intramural hematoma. J Thorac Cardiovasc Surg 1997; 114:619-26. [PMID: 9338648 DOI: 10.1016/s0022-5223(97)70052-7] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE This study sought to determine the transesophageal echocardiographic features and natural history of patients with aortic intramural hematoma. METHODS The transesophageal echocardiograms of all patients who had symptoms indicative of aortic dissection over 6 years were reviewed. Measurements were made of the involved aortic segment in the study patients, and follow-up was obtained. RESULTS In patients with aortic intramural hematoma, the wall thickness of the involved segment was significantly greater for descending segments than ascending segments (ascending aorta 7 +/- 2 mm, descending aorta 15 +/- 6 mm, p = 0.0016). In each case, the crescent-shaped intramural hematoma involved one wall predominantly, leading to compression of the aortic lumen. The findings of echolucent areas and displaced intimal calcium were found in the majority of patients. Four of eight patients with intramural hematoma of the ascending aorta were treated medically and four were treated surgically. The 30-day mortality was 50% in the medically treated patients and 0% in the surgically treated group. Four of 11 patients with isolated intramural hematoma of the descending aorta were treated medically and seven were treated surgically. All medically treated and 86% of surgically treated patients were alive at 30 days. CONCLUSIONS Aortic intramural hematoma has distinct and identifiable transesophageal echocardiographic features. These data support those of previous studies documenting high morbidity and mortality in patients with aortic intramural hematoma.
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Kelly S, Berry E, Roderick P, Harris KM, Cullingworth J, Gathercole L, Hutton J, Smith MA. The identification of bias in studies of the diagnostic performance of imaging modalities. Br J Radiol 1997; 70:1028-35. [PMID: 9404207 DOI: 10.1259/bjr.70.838.9404207] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The demand for evidence-based healthcare is increasing nationally and internationally and it is equally necessary in both diagnostic and therapeutic practice. Evidence may be collected and combined by means of a systematic literature review of published and unpublished data on a well-defined topic. The output of such reviews is then available to guide health policy, influence good practice or direct research. Published guidelines are available on the performance of systematic reviews, especially those of randomized controlled trials. Although there is an extensive literature base of research data in diagnostic imaging there are few such trials, but it is still possible to perform systematic reviews. With the alternative study designs encountered it is important to be aware of the main threats to study validity. In this paper the biases likely to be encountered in studies of diagnostic performance are reviewed, with particular reference to diagnostic imaging tests. The biases are sub-divided into three categories. The first category is patient selection and covers the validity of generalizing results beyond the study population. The other two, concerning study design and execution and the interpretation of results, affect the likely validity of the results of a study. An understanding of these factors is an essential prerequisite for those undertaking or using a systematic literature review in the field of diagnostic imaging. The definitions form the foundations of a defensible review protocol.
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Harris KM, Malenka DJ, Haney MF, Jayne JE, Hettleman B, Plehn JF, Griffin BP. Improvement in mitral regurgitation after aortic valve replacement. Am J Cardiol 1997; 80:741-5. [PMID: 9315580 DOI: 10.1016/s0002-9149(97)00506-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study sought to determine whether there is a quantitative improvement in mitral regurgitation (MR) after aortic valve replacement (AVR) for aortic stenosis (AS) and, if so, the mechanisms for this change. MR frequently accompanies AS. The addition of mitral valve replacement to AVR significantly increases the risk of surgery. Although previous studies have suggested a qualitative improvement in MR severity after AVR, semiquantitative analysis of this improvement has not been documented nor have the underlying mechanisms been examined. We evaluated 28 patients who had undergone 2-dimensional echo and color flow Doppler imaging an average of 1.5 +/- 2.5 months before and 2.5 +/- 4.2 months after AVR. Maximum MR area, MR percentage (MR area/left atrial area), mitral annular area, left atrial area, aortic gradient, and parameters of left ventricular geometry were measured to evaluate MR severity and to assess functional mechanisms for improvement in MR. There was a significant decrease in MR area (5.5 +/- 2.8 cm2 vs 2.5 +/- 1.9 cm2, p < or =0.0001) and MR percentage (25 +/- 11% vs 12 +/- 10% after operation, p < or =0.0001) between preoperative and postoperative studies. There was a significant reduction in aortic gradient, mitral annular area, left atrial area, and left ventricular length postoperatively. In univariate analysis, MR improvement was related to the lower preoperative left ventricular fractional area change (p = 0.027) and to the changes in fractional area change (p = 0.001) and left ventricular systolic area (p = 0.001). Thus, improvement in MR after AVR is related to changes in left ventricular function postoperatively. These data suggest that reduction in MR is due not only to decreased intraventricular pressure, but also to changes in ventricular morphology.
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Wu J, Chatman K, Harris K, Siuzdak G. An automated MALDI mass spectrometry approach for optimizing cyclosporin extraction and quantitation. Anal Chem 1997; 69:3767-71. [PMID: 9302875 DOI: 10.1021/ac970276y] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A combinatorial extraction method and an automated matrix-assisted laser desorption/ionization (MALDI) mass spectrometry procedure were used to improve the clinical analysis of the immunosuppressant drug cyclosporin A. Cyclosporin extracts from whole blood were analyzed by MALDI and electrospray ionization (ESI) mass spectrometry, allowing for their identification and quantification. Due to limitations associated with the current multistep cyclosporin extraction procedure from whole blood, a combinatorial approach was devised to optimize this extraction. Optimization was performed by generating an array of solvent systems to be used for extraction from blood, and an automated analysis was carried out on a MALDI mass spectrometer to identify successful extractions. The first generation of experiments revealed four binary solvent systems to be effective for cyclosporin extraction (hexane/EtOH, ACN/H2O, ACN/MeOH, and hexane/CHCl3). A new array based on these solvent systems was generated, and a second iteration of these experiments was then performed. In the second generation of experiments, hexane/CHCl3 (70:30) was found to provide the most effective single-step extraction of these solvent systems for cyclosporin and its metabolites. The limits of detection were determined to be 15 ng/mL in whole blood for ESI/MS and MALDI-MS and could also be used for identifying major drug metabolites. In addition to applying this combinatorial approach to extraction procedures, this experimental design could easily be extended to examine other approaches, such as optimizing chemical reactions and screening inhibitors in enzymatic reactions.
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Resnick MD, Bearman PS, Blum RW, Bauman KE, Harris KM, Jones J, Tabor J, Beuhring T, Sieving RE, Shew M, Ireland M, Bearinger LH, Udry JR. Protecting adolescents from harm. Findings from the National Longitudinal Study on Adolescent Health. JAMA 1997; 278:823-32. [PMID: 9293990 DOI: 10.1001/jama.278.10.823] [Citation(s) in RCA: 1011] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
CONTEXT The main threats to adolescents' health are the risk behaviors they choose. How their social context shapes their behaviors is poorly understood. OBJECTIVE To identify risk and protective factors at the family, school, and individual levels as they relate to 4 domains of adolescent health and morbidity: emotional health, violence, substance use, and sexuality. DESIGN Cross-sectional analysis of interview data from the National Longitudinal Study of Adolescent Health. PARTICIPANTS A total of 12118 adolescents in grades 7 through 12 drawn from an initial national school survey of 90118 adolescents from 80 high schools plus their feeder middle schools. SETTING The interview was completed in the subject's home. MAIN OUTCOME MEASURES Eight areas were assessed: emotional distress; suicidal thoughts and behaviors; violence; use of 3 substances (cigarettes, alcohol, marijuana); and 2 types of sexual behaviors (age of sexual debut and pregnancy history). Independent variables included measures of family context, school context, and individual characteristics. RESULTS Parent-family connectedness and perceived school connectedness were protective against every health risk behavior measure except history of pregnancy. Conversely, ease of access to guns at home was associated with suicidality (grades 9-12: P<.001) and violence (grades 7-8: P<.001; grades 9-12: P<.001). Access to substances in the home was associated with use of cigarettes (P<.001), alcohol (P<.001), and marijuana (P<.001) among all students. Working 20 or more hours a week was associated with emotional distress of high school students (P<.01), cigarette use (P<.001), alcohol use (P<.001), and marijuana use (P<.001). Appearing "older than most" in class was associated with emotional distress and suicidal thoughts and behaviors among high school students (P<.001); it was also associated with substance use and an earlier age of sexual debut among both junior and senior high students. Repeating a grade in school was associated with emotional distress among students in junior high (P<.001) and high school (P<.01) and with tobacco use among junior high students (P<.001). On the other hand, parental expectations regarding school achievement were associated with lower levels of health risk behaviors; parental disapproval of early sexual debut was associated with a later age of onset of intercourse (P<.001). CONCLUSIONS Family and school contexts as well as individual characteristics are associated with health and risky behaviors in adolescents. The results should assist health and social service providers, educators, and others in taking the first steps to diminish risk factors and enhance protective factors for our young people.
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Resnick MD, Bearman PS, Blum RW, Bauman KE, Harris KM, Jones J, Tabor J, Beuhring T, Sieving RE, Shew M, Ireland M, Bearinger LH, Udry JR. Protecting Adolescents From Harm. JAMA 1997. [PMID: 9293990 DOI: 10.1001/jama.1997.03550100049038] [Citation(s) in RCA: 1603] [Impact Index Per Article: 59.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Abstract
Radiographic imaging of the breast began in the early years of the twentieth century. Continuous advances in film quality, energy sources, targets, grids, and filters have all contributed to superior image resolution. Federal quality standards now regulate screening mammography, and mass screening for breast cancer has become widely accepted in the United States. Wider application of screening has resulted in a dramatic apparent increase in incidence rates of breast cancer; a large proportion of this increase is in ductal carcinoma in situ. During the past 30 years, nine prospective, randomized trials to evaluate the ability of screening mammography to reduce mortality from breast cancer have been completed. These trials show a 30% reduction in mortality for women ages 50-69 years, but the benefit to women aged 40-49 years remains uncertain. This uncertainty is largely attributable to the lack of properly designed and conducted studies to evaluate screening efficacy in younger women. Although there is no biological reason to predict poor screening performance in the younger age groups, the sensitivity of screening mammography is lower in younger women. Additional data suggest that screening intervals longer than 12 months are ineffective in women younger than 50 years. With shorter screening intervals, the cost associated with screening mammography is comparable to other life-saving measures widely applied in the population. New breast imaging techniques hold promise for superior image quality, but they remain investigational as tools for mass screening. Until primary prevention of breast cancer is a reality, mass screening remains available to reduce mortality from breast cancer.
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Kanbour-Shakir A, Harris KM, Johnson RR, Kanbour AI. Breast care consultation center: role of the pathologist in a multidisciplinary center. Diagn Cytopathol 1997; 17:191-6. [PMID: 9285190 DOI: 10.1002/(sici)1097-0339(199709)17:3<191::aid-dc4>3.0.co;2-i] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The Breast Care Consultation Center (BCCC) is a multidisciplinary center providing, in a single setting, a complete outpatient facility for women who have been diagnosed with or suspected of having breast cancer. A team of specialists are available to provide comprehensive, diagnostic (radiologist, surgeon, and pathologist), therapeutic (surgeon, radiotherapist, and medical oncologist), and support options. The pathologist, as a member of the diagnostic team, evaluates the material obtained or received at the BCCC. These include fine-needle aspirations (FNAs) obtained on-site as well as previously prepared cytohistological specimens. The pathologist renders the diagnosis following examination of the material and consultation with the multidisciplinary team. Thus, this approach is conducive for appropriate and accurate diagnosis where all data are available. In addition, the pathologist discusses the findings of each patient in the multidisciplinary conference. One thousand four hundred eighteen patients were evaluated at Magee-Womens Hospital BCCC from February 1992 through December 1994, during which time 366 FNAs were performed. The accuracy for positive diagnosis was 100%. Six negative cases had cancer on histology; these were due to sampling error (the lesion was missed). A multidisciplinary team is ideal for the evaluation of breast lesions that are suspicious for malignancy as it provides one-stop shopping and same-day diagnosis and therapeutic decisions.
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