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PubMed2006

The cochlear-carotid interval: anatomic variation and potential clinical implications.

BACKGROUND AND PURPOSE: A temporal bone CT study in a patient with episodic mid-tone sensorineural hearing loss and tinnitus demonstrated absence of bone between the petrous internal carotid artery and the basal turn of the cochlea. The potential implications with respect to increasingly popular cochlear implant surgery compelled us to retrospectively analyze a series of temporal bone CT scans to establish typical measurements for this region, which we termed the "cochlear-carotid interval" (CCI). METHODS: After IRB exemption, 2 observers independently measured the bony interval between the cochlea and the petrous internal carotid artery canal on coronal images from 30 consecutive temporal bone CT studies. The 1-mm thick coronal images were either acquired directly or were reconstructed from an axial dataset acquired at 0.75 or 0.6 mm section thickness. All measurements were performed by using electronic calipers on a Sienet MagicView VE 42 Siemens PACS station. Mixed model analysis of variance was used to evaluate differences between readers and sides with respect to the mean CCI but adjusted for age and accommodating the correlation among observations generated for the same subject. RESULTS: The patient in our case report had a right CCI of 0.2 mm and left CCI of 0.0 mm. In the other 30 patients, the right CCI ranged from 0.2 to 3.8 mm (mean, 1.2 +/- 0.8 mm; median, 0.9) and the left CCI from 0.2 to 5.0 mm (mean, 1.1 +/- 0.9 mm; median, 0.8). The CCI did not exhibit a significant association with subject age (P = .1336), and there were no significant differences between readers (P = .824) or sides (P = .350) in terms of mean CCI. CONCLUSION: The CCI varies widely between patients and may be as small as zero. Analysis of anatomic relationships suggests a potential relationship between small CCI and mid-tone sensorineural hearing loss, as in our reported patient. Preoperative knowledge of thin or absent bone between the cochlea and petrous carotid canal may help prevent inadvertent penetration of the carotid canal during cochlear implant surgery.

Adolescent↗

PubMed1994

Force delivery properties of colored elastomeric modules.

Elastomeric chains have been used by clinicians for some time to accomplish various treatment objectives. Recently, a number of manufacturers have added colored elastomeric chains to their inventories. The present study was designed to investigate the force delivery capabilities and dimensional stability of these new colored chains. Four different colors of short filament configuration produced by three manufacturers were examined. The force delivery capabilities of each chain were tested at 0 hours and, after storage at 37 degrees C in air, distilled water, and artificial saliva, at 1 hour, 4 hours, 24 hours, 1 week, 2 weeks, and 3 weeks. A universal testing machine was used to determine the amount of distraction necessary to generate 150 and 300 gf. Dimensional measurements were assessed initially and, after exposure to a simulated oral environment, at 1, 2, and 3 weeks. The data from the force delivery portion of the study were analyzed with a 4-factor factorial analysis of variance. The data compiled from the dimensional stability portion were subjected to a 3-factor factorial analysis of variance. Follow-up Bonferroni simultaneous t tests (family-wise a priori alpha p < 0.05) was used to determine statistical significance of the differences among sets of means. All colored elastomeric chains in the study appeared capable of initially generating force levels compatible with tooth movement. After 24 hours of storage in liquid, the amount of distraction needed to produce 150 and 300 gf substantially increased. The amount of increased need varied among manufacturers. All chains showed an increase in dimensional measurements after 1 week, with little change thereafter.

Analysis of Variance↗

PubMed2006

Global model analysis by parameter space partitioning.

To model behavior, scientists need to know how models behave. This means learning what other behaviors a model can produce besides the one generated by participants in an experiment. This is a difficult problem because of the complexity of psychological models (e.g., their many parameters) and because the behavioral precision of models (e.g., interval-scale performance) often mismatches their testable precision in experiments, where qualitative, ordinal predictions are the norm. Parameter space partitioning is a solution that evaluates model performance at a qualitative level. There exists a partition on the model's parameter space that divides it into regions that correspond to each data pattern. Three application examples demonstrate its potential and versatility for studying the global behavior of psychological models.

Humans↗

PubMed1995

Structure-function analysis of the vitamin B12 receptor of Escherichia coli by means of informational suppression.

We describe a genetic analysis of the vitamin B12 receptor of Escherichia coli. Through the use of informational suppression, we have been able to generate a family of receptor variants, each identical save for a single, known substitution (Ser, Gln, Lys, Tyr, Leu, Cys, Phe) at a known site. We have studied 22 different mutants, 14 in detail, distributed throughout the length of the btuB gene. Most amino acid substitutions have a pleiotropic effect with respect to all ligands tested, the two colicins E1 and E3, the T5-like bacteriophage BF23, and vitamin B12. (The dramatic effect of a single amino acid substitution is also well exemplified by the G142A missense change which renders the receptor completely non-functional.) In some instances, however, we have been able to modify a subset of receptor functions (viz. Q62, Q150 and Q299 and the response to phage BF23). These data are summarized on a two-dimensional folding model for the BtuB protein in the outer membrane (devised using both amphipathic beta-strand analysis and sequence conservation amongst the TonB-dependent receptors). In addition, we report that the extreme C-terminus of BtuB is vital for receptor localization and provide evidence for it being a membrane-spanning beta-sheet with residue L588 situated on its hydrophobic surface. Two of the C-terminal btuB mutations are located within the region of overlap with the recently identified dga (murl) gene.

Amino Acid Sequence↗

PubMed2001

A propensity analysis of cigarette smoking and mortality with consideration of the effects of alcohol.

Although it is well established that cigarette smoking causes excess mortality, the extent of the increased risk has been challenged because self-selection biases and confounding factors may not have been adequately accounted for in prior studies. We therefore performed a propensity analysis on a population-based cohort. A logistic regression model was used to generate a propensity score for current smoking in 6,099 adults (mean age 46 years, 54% men, 36% current smokers) participating in the National Heart Lung and Blood Institute's (NHLBI) Lipid Research Clinic Prevalence Study. During 12 years of follow-up, 513 subjects (8%) died. After adjusting for age, current smoking was strongly associated with death (compared with never and former smokers, relative risk [RR] 2.69, 95% confidence interval [CI] 1.98 to 0.64, p <0.0001 and RR 1.79, 95% CI 1.26 to 2.55, p = 0.001, respectively). After adjusting for a propensity score based on 27 covariates and the covariates themselves, current smoking remained strongly and independently predictive of excessive death risk in smokers compared with never and former smokers (adjusted RR 2.96, 95% CI 2.16 to 4.05, p <0.0001 and adjusted RR 1.87, 95% CI 1.31 to 2.67, p = 0.0006, respectively). Although smokers were more likely to also drink alcohol, an interaction was noted, whereby, after adjustment for propensity score and other covariates, current smoking was associated with a moderately strong increase in mortality among drinkers (adjusted RR 2.00, 95% CI 1.42 to 2.82, p <0.0001), but was also associated with a markedly increased death risk among nondrinkers (adjusted RR 4.74, 95% CI 3.24 to 6.92, p <0.0001). The independent association of smoking with death even after a rigorous propensity analysis argues that it is highly unlikely that the link between smoking and mortality is materially biased or confounded.

Adult↗

PubMed2004

Numerical analysis of the anaerobic co-digestion of the organic fraction from municipal solid waste and wastewater: prediction of the possible performances at Olmeto plant in Perugia (Italy).

Anaerobic digestion is mainly used for sewage sludge stabilization and for treatment of waste that has a high organic content. It also represents a powerful method for obtaining energy by means of natural gas production. Co-digestion particularly combines different organic substrates to generate a homogeneous mixture as input to the anaerobic reactor in order to increase process performance. Reactions kinetics and knowledge of process analysis represent the keys for good planning and correct management. In this paper a model to simulate the main reactions involved in anaerobic co-digestion is presented. The model was created to analyse the possible performance of the treatment plant in Olmeto, Marsciano (Perugia) in Italy. The plant is still in an experimental phase with regard to the co-digestion process and numerical simulations represent a useful tool during development of the correct management procedures for the operational phase and a good methodoly for addressing further pilot plant experiments.

Bacteria, Anaerobic↗

PubMed1995

Localisation of ventricular tachycardia substrates by analysis of the surface QRS recorded during ventricular tachycardia.

BACKGROUND: Analysis of the surface ECG can predict the locations of pacing foci but is of limited value for locating arrhythmogenic substrates causing ventricular tachycardia because of the effects of myocardial infarction, ischaemia, and bundle branch block on ventricular activation. AIM: To determine whether analysis of the initial 60 ms segment of the surface QRS improves the accuracy of the ECG for predicting ventricular tachycardia origin we correlated the locations of 37 arrhythmogenic areas present in 20 patients with the 3D vectors of the ventricular tachycardias generated by each respective area. METHODS: The 3D vector of each ventricular tachycardia morphology was calculated from the integrals of the initial 60 ms of the surface vectorcardiogram and from the entire QRS recorded in each lead of the Frank orthogonal lead vectorcardiogram. Sixty eight-morphologies of ventricular tachycardia were mapped using simultaneous recordings from 60 catheter electrodes. RESULTS: Ventricular tachycardias with 3D vectors directed inferiorly and posteriorly or superiorly and anteriorly were more likely to originate from the septum, P = 0.04, whereas tachycardias directed superiorly and to the right were more likely to originate from the inferior wall and the cardiac apex, P = 0.001. However, the same arrhythmogenic area could generate multiple ventricular tachycardias with different 3D vectors. In addition, ventricular tachycardias with similar 3D vectors were generated by arrhythmogenic areas in the septal, apical and inferior walls. The variances of the mean 3D vectors of ventricular tachycardias originating from each of 12 different cardiac regions were no different when based on the initial 60 ms of the surface QRS than on the entire surface QRS. CONCLUSION: Analysis of the surface ECG provides only an approximate guide to the locations of arrhythmogenic areas generating ventricular tachycardia even when analysis is restricted to the initial forces in the surface QRS. Therefore, detailed mapping is needed to accurately determine the number and location of arrhythmogenic areas.

Bundle-Branch Block↗

PubMed2006

Incidence, time course, and characteristics of microbubble formation during radiofrequency ablation of pulmonary veins with an 8-mm ablation catheter.

BACKGROUND: Microbubble formation during pulmonary vein (PV) radiofrequency (RF) ablation of atrial fibrillation (AF) occurs relatively frequently. Prior studies have shown that microbubble formation may be associated with an increased risk of complications. However, the incidence, time course, and temperature characteristics of microbubble formation during AF ablation with an 8-mm catheter have not been prospectively described in humans. METHODS: We studied 46 (30 men, age 56+/-10 years) patients with AF who underwent RF ablation of PVs between January 2005 and December 2005 using an 8F, 8-mm Biosensetrade mark ablation catheter (Biosense-Webster, Diamond Bar, CA, USA). All patients underwent continuous intracardiac echocardiography (ICE). Microbubble patterns were classified as either type 1 (intermittent, scattered microbubble formation) or type 2 (explosive shower of dense microbubbles). Formation of any microbubbles was detected by ICE and the time, PV location, and electrode temperature were recorded. RESULT: A total of 1,479 (32+/-13, range 12-73) RF lesions were delivered to 167 veins. Twenty (2%) lesions were classified as type 2. Since the number of lesions resulting in type 2 bubbles was very small, only type 1 lesions were included in the final analysis. Thirty-nine (85%) patients had at least one lesion associated with bubble formation during ablation (mean: 7+/-7 lesions, range 1-28 lesions). Twenty-three percent (327) of the RF lesions resulted in bubble formation. RF generator power setting during lesions resulting in bubble formation was lower than lesions which did not result in bubble formation (47.9+/-7.4 W vs 49.7+/-7.1 W, P<0.001). Logistic regression analysis revealed a significant negative correlation (P<0.001) between RF generator power settings and a positive correlation between the generator temperature settings and formation of bubbles (both P<0.02). However, the maximum temperature attained was not different between lesions resulting in bubble formation (n=327) and those which did not result in bubble formation (n=1,139). Fifty-three (16%) of the lesions associated with bubble formation occurred within 2-10 seconds after RF was begun. Bubble formation was significantly more frequent in left superior PVs compared to the other PVs (left superior PV 27.3% left inferior PV 18.6%, right superior PV 20.5%, and right inferior PV 18.8%, P=0.005, left superior PV vs other PVs, P<0.001) even after adjustment for the other factors including generator power settings and the temperature setting. CONCLUSION: Bubble formation is common during RF ablation of PV with 8-mm tip catheter and can occur as early as 2 seconds after starting RF. RF generator power is negatively correlated with bubble formation while generator temperature settings are positively correlated with formation of bubbles. Microbubble formation is also more frequent with ablation of the left superior PV probably due to better catheter contact in that area.

Atrial Fibrillation↗

PubMed1989

Automated morphometric study of human peripheral nerves by image analysis.

In this paper we describe a program using the image analyzer SAMBA, which allows an automatic analysis of silver stained semithin nerve sections. The operator can interactively delimit the contour of the fascicle to be analysed by means of a digitizing tablet connected to the system which generates a mask of the region. Segmentation of the fibre images is conducted as a function of brightness threshold defined by the operator. Fibre clusters are automatically separated using morphological procedures like dilatation. Morphometric parameters such as the external and axonal diameters, myelin sheath thickness and circularity are measured. We are now testing this method on normal and pathological human superficial peroneal nerves. Preliminary results are promising and the development of adequate statistical analysis of morphometric data will provide us with a new tool for the diagnosis of peripheral neuropathies.

Humans↗

PubMed2001

Coronary artery bypass surgery: are outcomes influenced by demographics or ability to pay?

OBJECTIVE: To examine the relation of financial status and demographics to the outcomes of coronary artery bypass surgery (CABG) in the public hospital setting. SUMMARY BACKGROUND DATA: Coronary artery bypass surgery is one of the most expensive and frequently performed surgical procedures in the United States. Considerable controversy surrounds the accessibility to quality cardiac care of indigent and minority populations. This study examines the hypothesis that demographics rather than access to care and economics influences outcomes in CABG. METHODS: A retrospective review of 1,556 charts of patients who underwent CABG at Louisiana State University Health Sciences Center-Shreveport, a public hospital, during a 10-year period was performed. The parameters analyzed included sex, age, race, education, ejection fraction, comorbidities, surgical parameters, economics, complications, and cost of care. Comparisons were made between the insured and uninsured groups. Univariate statistical analysis was used to assess differences between groups. Kaplan-Meier survival curves were also generated. RESULTS: Two thirds of the patients were uninsured. The mean age of the uninsured patients was significantly lower than that of the insured patients. Ejection fractions were comparable. Comorbidities were similar, with a greater percentage of tobacco use in the uninsured population. Kaplan-Meier survival curves showed that the uninsured group had better overall survival and that the insured group manifested an increased rate of late death. CONCLUSIONS: The financially challenged population appears to present for treatment earlier in life with coronary artery disease. Risk factors between the two groups were similar, except that tobacco use appears to be a significant problem in the disadvantaged population. The disease severity in both populations appeared to be similar; however, the uninsured patients had equivalent early survival with better late survival. Access to care in both groups was equal. In the public hospital setting for the disease state described, the financially challenged are afforded access to the current treatment technology with quality results.

Coronary Artery Bypass↗

PubMed2005

Nebulization associated with bi-level noninvasive ventilation: analysis of pulmonary radioaerosol deposition.

UNLABELLED: Nebulization associated with noninvasive ventilation is used in emergency services and intensive care units. PURPOSES: To compare pulmonary radioaerosol deposition during jet nebulization associated to noninvasive ventilation versus spontaneous breathing nebulization; to measure the rate of lung depuration and the correlation between lung deposition, inspiratory flow and tidal volume (V(t)) using scintigraphy. SUBJECTS: Thirteen healthy volunteers (with normal spirometry), mean age (23.3+/-1.49) years, body mass index 21.2+/-2.3 kg/m(2). METHODS: Nebulization was performed in spontaneous breathing and associated with bi-level noninvasive ventilation (inspiratory pressure=12 cm H(2)O, expiratory pressure=5 cm H(2)O). The radioaerosol used in the nebulization was technetium (Tc99m) with diethylene triamine penta acetic acid, generated over a period of 9 min in a jet nebulizer. Analysis was performed through scintigraphy. Statistical analysis was performed by analysis of variance (for repeated measures), Bonferroni method, Student's t-test and Person's correlation. RESULTS: There was a decrease in radioaerosol lung deposition with nebulization associated to noninvasive ventilation (mean counts in spontaneous breathing 200,510+11,012 and mean counts in noninvasive ventilation 106,093+2811 (P<0.001). During spontaneous breathing nebulization there was a significant correlation between V(t) and radioaerosol deposition (r=0.565, P<0.05), also between inspiratory flow and radioaerosol deposition in the lungs (r=0.141, P<0.05). However, there was no correlation between V(t) and pulmonary deposition of radioaerosol in bi-level noninvasive ventilation nebulization (r=0.082). CONCLUSION: During nebulization with noninvasive ventilation in healthy volunteers, there was an increase in V(t) associated to a higher inspiratory flow rate, without resulting in a significant increase in pulmonary radioaerosol deposition.

Administration, Inhalation↗

PubMed1982

Age-related effects on the number of human lymphocytes in culture initially responding to an antigenic stimulus.

Lymphocyte transformation responses to the antigen streptokinase-streptodornase were evaluated in a group of 14 healthy elderly subjects by enumeration of antigen-responsive cells, first-generation responding lymphocytes and progeny generated per responding cell. Peak lymphocyte transformation responses to the antigen were diminished in the elderly subjects when compared to a group of young adult subjects. Antigen-responsive cells were found by limiting-dilution analysis to be significantly decreased in the elderly subjects (geometric means of antigen-responsive cells per 10(5) mononuclear cells = 4.35 in the elderly versus 14.79 in the younger group, P less than 0.001). The number of cells recruited into the first-generation lymphocyte response per antigen-responsive cell were equivalent in the two groups. Also, the proliferation into progeny of each first-generation lymphocyte was of the same magnitude for the elderly and young subjects within the six to eight cell divisions required for this response. Therefore, in this system the diminished total lymphocyte transformation responses to the antigen streptokinase-streptodornase of cells from elderly humans can be accounted for by a reduction in the number of lymphocytes initially responsive to the antigen.

Adult↗

PubMed2000

Compound heterozygosity for a disease-causing G1489E [corrected] and disease-modifying G530S substitution in COL5A1 of a patient with the classical type of Ehlers-Danlos syndrome: an explanation of intrafamilial variability?

The classical type of Ehlers-Danlos syndrome (EDS) is an autosomal dominant connective tissue disorder characterized by skin hyperelasticity, tissue fragility, and joint hypermobility. We investigated the molecular defect of EDS in a three-generation family. Cultured dermal fibroblasts from the propositus and his daughter produced abnormal alpha1(V) and alpha2(V) collagen molecules. Mutation analysis by means of RNase cleavage and direct sequencing of reverse transcription-polymerase chain reaction products showed in both the presence of a heterozygous G1489E [correction] mutation in the COL5A1 gene, which represents the first report of a glycine substitution in the main triple-helical region of alpha1(V) collagen. In the propositus, his unaffected daughter, and mother we identified a further newly recognized G530S substitution in the NH2-terminal domain, which did not cosegregate with the EDS phenotype and was found in only one of 51 unrelated control individuals. Because the NH2-terminal domain plays a crucial role in modulating fibril formation, the G530S substitution may alter the structure and function of this region and consequently the formation of collagen fibrils. Indeed, indirect evidence supports our hypothesis: (1) the EDS phenotype in the compound heterozygous propositus is more severe than that of his affected daughter with the G1489E [correction] mutation only; (2) his unaffected daughter and mother with the G530S substitution present with thin skin and delayed wound healing; (3) as does the only control individual with the same substitution. Thus, in the compound heterozygous propositus the EDS phenotype is caused by the G1489E [correction] mutation and possibly aggravated by the G530S substitution, which may explain intrafamilial variability.

Adult↗

PubMed1979

Peripheral auditory input to the midbrain limbic area and related structures.

The effect of peripherally applied auditory stimulation on unit activity in midbrain limbic and related regions was investigated in the freely behaving rat. Two pure tones (1 and 10 kHz) and a noise generated by the discharge of a solenoid were used as stimuli presented randomly with 1 min mean interval between presentations. Computer-aided analysis of unit activity indicated that (1) a high proportion of neurons in the limbic midbrain region give excitatory responses to the three stimuli; (2) a majority of the responses have short latencies, especially in the dorsal raphe nucleus; (3) frequency and physical properties of the stimuli seemed not crucial for eliciting responsiveness; (4) habituation to repeated presentation of stimuli was not characteristic of the excitatory responses in the limbic midbrain region. These results are discussed in the light of possible functions of this region.

Acoustic Stimulation↗

PubMed1999

Thromboxane receptors in human kidney tissues.

Thromboxane (TX) A2 effects in the kidneys include contraction of glomerular mesangial cells and intrarenal vascular tissue. A kidney cDNA encoding a TX receptor expressed in rat renal glomeruli and rat renal arterial smooth muscle cells has been reported. However, TXA2 receptors in human kidneys have not been documented. The purpose of this study was to identify and characterize TXA2 receptors in glomeruli and intrarenal arteries isolated from human kidneys. Normal kidneys, not used for transplant because of technical reasons, were kept at -70 degrees C and used for research purposes. The glomeruli and intrarenal arteries were isolated from renal cortical tissue by a mechanical sieving technique. The equilibrium dissociation constant and receptor number were determined by nonlinear analysis of binding inhibition data. The data were generated in radioreceptor assays using [125I]-BOP, a stable analog of TXA2. The dissociation constants (mean +/- SEM) for binding of I-BOP to human glomeruli and intrarenal arterial membranes were 6.6 +/- 1.1 nM (n = 7) and 20 +/- 6 nM (n = 7), respectively (p < 0.05). The receptor number was 311 +/- 91 fmol/mg protein (n = 7) in glomeruli and 74 +/- 16 fmol/mg protein (n = 7) in intrarenal arterial membranes (p < 0.04). The order of specificity of TXA2 analogs for [125I]-BOP binding sites was similar in glomeruli and in arterial membranes and was I-BOP > or = U46619 > or = pinane TXA2 > or = carbocyclic TXA2 > or = PGH2. These findings provide direct evidence for the presence of specific, high-affinity [125I]-BOP binding sites in human renal glomeruli and extraglomerular vascular tissue. These data also indicate that the human binding sites have higher affinity for the TXA2 agonist I-BOP than for PGH2.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

PubMedDate not supplied

Life after a cardiac event: women's experience in healing.

OBJECTIVE: To describe the experience of women's recovery after an acute cardiac event. DESIGN: Grounded theory provided the methodologic basis for qualitative data generation and analysis. SAMPLE: Thirteen women who had experienced an acute cardiac event. The participants' ages ranged from 42 to 78 with a mean age of 58 years. Four participants attended the group sessions after experiencing an acute myocardial infarction; five had undergone coronary artery bypass grafting; and two had undergone percutaneous transluminal coronary angioplasty. Two participants had undergone exercise testing that indicated myocardial ischemia. The time after the cardiac event ranged from 8 weeks to 3 years at the initiation of the study, with a mean time after the cardiac event of 8 months. RESULTS: Healing, the basic social process identified from the data, explained women's struggle through the uncertainty surrounding the cardiac event as a way of creating new and positive health patterns. The process of healing consisted of three stages: surviving, originating, and patterning balance. These stages of healing illustrated determinants of individual motivation that guided the initiation and maintenance of risk factor modification efforts in women after the cardiac event. CONCLUSIONS: Results of this study provide a basis for the development and evaluation of comprehensive rehabilitative interventions designed to enhance individual recovery after a cardiac event.

Adaptation, Psychological↗

PubMed2004

Validation of the conceptual anatomical model of the lung airway.

The conceptual anatomical model of the lung airway considers each lung volume divided into ten concentric shells. It specifies the volume of each airway generation in each shell, using Weibel morphometry. This study updates and validates the model and evaluates the errors obtained when using it to estimate inhaled aerosol deposition per generation from spatial imaging data. A comparison of different airway models describing the volume per generation, including data from CT images of a lung cast and a human subject, was performed. A revised version of the conceptual model was created, using the average volume per generation from these data. The new model was applied to derive the aerosol deposition per generation from 24 single photon emission computed tomography (SPECT) studies. Analysis errors were assessed by applying the same calculations but using airway models based on the minimum and maximum volumes per generation. The mean shell position of each generation in the average model was not significantly different from either CT model. However there were differences between the volumes per generation of the different models. The root mean square differences between bronchial airways deposition fraction (generations 2-8) obtained from the maximum and minimum models compared to the new average model was 0.66 percentage points (14%). For the conducting airways deposition fraction (generations 2-15) this was 1.66 percentage points (12%). The conceptual model is consistent with CT measurements of airway geometry. The errors resulting from using a generic airway model to interpret 3D radionuclide image data have been defined.

Humans↗

PubMed1994

Evaluation of a new slide-based laser scanning cytometer for DNA analysis of tumors. Comparison with flow cytometry and image analysis.

DNA measurements generated by a new automated slide-based cytometer, the laser scanning cytometer (LSC), were compared with those produced by commercial flow cytometry (FCM) and image analysis (IA) devices. Laser scanning-cytometric analysis was performed by scanning alcohol-fixed, propidium iodide-stained tumor imprints with a 5-microns spot laser beam. Fifty-three malignant tumors (51 breast carcinomas and 2 lung carcinomas) were studied. Ploidy concordance rates for FCM versus LSC, IA versus LSC, and FCM versus IA were 96%, 91%, and 91%, respectively. Statistically significant agreement between methods was determined by linear regression analysis of DNA indices. Synthesis-phase fractions generated by FCM and LSC also were comparable, as demonstrated by linear regression (r = .83). Mean coefficients of variation for the LSC compared favorably with those for FCM and IA. The few discrepancies in ploidy status between methods could be explained by sampling error, the presence of possible near-diploid aneuploid populations that could not be effectively resolved by one or another modality, and the visual selection bias with IA when small aneuploid cell populations were present. The LSC shares many useful features with FCM, including automation, accuracy of quantitation, rapidity, and generation of reliable information regarding cell proliferation (synthesis-phase fraction). In addition, it has some of the advantages of IA, such as minimal tissue requirement, no need for special preparation, and the potential for visual selection of the cells measured. The LSC holds great promise for use in the clinical laboratory because of these combined characteristics.

Breast Neoplasms↗