Showing papers by "Sapienza University of Rome published in 1990"
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TL;DR: In this article, the authors give a brief overview of the impact of fractal geometry on physical sciences and the recent developments in the direction of the formulation of an analytical theory that allows to understand why natural phenomena often give rise to fractal structures.
Abstract: We give a brief overview of the impact of fractal geometry on physical sciences. In particular we will describe the prototype of fractal growth models and the recent developments in the direction of the formulation of an analytical theory that allows to understand why natural phenomena often give rise to fractal structures. Finally we will show that the large scale properties of the matter distribution in the universe need a radical revision on the of light of these new concepts.
668 citations
01 Jan 1990
TL;DR: The functional architecture of auditory-verbal (Phonological) Short-Term Memory and its Neural Correlates has been discussed in this paper, with a focus on the role of lexical information sources in immediate recall.
Abstract: List of contributors Acknowledgements General introduction Part I. The Functional Architecture of Auditory-Verbal (Phonological) Short-Term Memory and its Neural Correlates: 1. The impairment of auditory-verbal short-term storage Tim Shallice and Giuseppe Vallar 2. The development of the concept of working memory: implications and contributions of neuropsychology Alan D. Baddeley 3. Multiple phonological representations and verbal short-term memory Frances J. Friedrich 4. Electrophysiological measures of short-term memory Arnold Starr, Geoffrey Barrett, Hillel Pratt, Henry J. Michalewski and Julie V. Patterson Part II. Phonological Short-Term Memory and Other Levels of Information Processing: Studies in Brain-Damaged Patients with Defective Phonological Memory: 5. Auditory and lexical information sources in immediate recall: evidence from a patient with deficit to the phonological short-term store Rita Sloan Berndt and Charlotte C. Mitchum 6. Neuropsychological evidence for lexical involvement in short-term memory Eleanor M. Saffran and Nadine Martin 7. Auditory-verbal span of apprehension: a phenomenon in search of a function? Rosaleen A. McCarthy and Elizabeth K. Warrington 8. Short-term retention without short-term memory Brian Butterworth, Tim Shallice and Frances L. Watson Part III. Short-Term Memory Studies in Different Populations (Children, Elderly, Amnesics) and of Different Short-Term Memory Systems: 9. Developmental fractionation of working memory Graham J. Hitch 10. Adult age differences in working memory Fergus I. M. Craik, Robin G. Morris and Mary L. Gick 11. Lipreading, neuropsychology and immediate memory Ruth Campbell 12. Memory without rehearsal David Howard and Sue Franklin 13. The extended present: evidence from time estimation by amnesics and normals Marcel Kinsbourne and Robert E. Hicks Part IV. Phonological Short-Term Memory and Sentence Comprehension: 14. Short-term memory and language comprehension: a critical review of the neuropsychological literature David Caplan and Gloria S. Waters 15. Neuropsychological evidence on the role of short-term memory in sentence processing Randi C. Martin 16. Short-term memory impairment and sentence processing: a case study Eleanor M. Saffran and Nadine Martin 17. Phonological processing and sentence comprehension: a neuropsychological case study Giuseppe Vallar, Anna Basso and Gabriela Bottini 18. Working memory and comprehension of spoken sentences: investigation of children with reading disorder Stephen Crain, Donald Shankweiler, Paul Macaruso and Eva Bar-Shalom Name index Subject index.
565 citations
TL;DR: Results indicate that motor cortical cells can code direction of movement in a way which is dependent on the position of the arm in space, and movement population vectors computed from cell activity proved to be good predictors of movement direction regardless of where in space the movements were performed.
Abstract: The activity of 176 individual cells in the arm area of motor cortex (areas 4 and 6) was studied while monkeys made arm movements of similar direction within different parts of extrapersonal space The behavioral paradigm used was a 3-dimensional reaction-time task aimed at dissociating the direction of movement, which remained similar across the work space, from the patterns of muscular activity and the angular joint excursions necessary to perform these movements In agreement with other studies (Georgopoulos et al, 1982; Schwartz et al, 1988), we found that, within a given part of space, the activity of 169 (960%) cells studied increased most for a given preferred direction and less for other directions of movement This change was graded in an orderly fashion We further analyzed the orientation in space of the cells' preferred directions under the differing conditions of the task We found that, as movements with similar trajectories were made within different parts of space, the cells' preferred directions changed spatial orientation This change was of different magnitudes for different cells, but at the level of the population, it followed closely the changes in orientation of the arm necessary to perform the movements required by the task Movement population vectors (Georgopoulos et al, 1983, 1986, 1988) computed from cell activity proved to be good predictors of movement direction regardless of where in space the movements were performed These results indicate that motor cortical cells can code direction of movement in a way which is dependent on the position of the arm in space The data are discussed in relation to the existence of mechanisms which facilitate the transformation between extrinsic and intrinsic coordinates These transformations are necessary to perform arm movements to visual targets in space
543 citations
01 Apr 1990-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: The L3 experiment as discussed by the authors is one of the six large detectors designed for the new generation of electron-positron accelerators, which is the only detector that concentrates its efforts on limited goals of measuring electrons, muons and photons.
Abstract: The L3 experiment is one of the six large detectors designed for the new generation of electron-positron accelerators. It is the only detector that concentrates its efforts on limited goals of measuring electrons, muons and photons. By not attempting to identify hadrons, L3 has been able to provide an order of magnitude better resolution for electrons, muons and photons. Vertices and hadron jets are also studied. The construction of L3 has involved much state of the art technology in new principles of vertex detection and in new crystals for large scale electromagnetic shower detection and ultraprecise muon detection. This paper presents a summary of the construction of L3.
505 citations
TL;DR: In this paper, the superselection structure in the vacuum sector can be described by a unique compact global gauge group acting on a field algebra generated by field operators which commute or anticommute at spacelike separations.
Abstract: Given the local observables in the vacuum sector fulfilling a few basic principles of local quantum theory, we show that the superselection structure, intrinsically determined a priori, can always be described by a unique compact global gauge group acting on a field algebra generated by field operators which commute or anticommute at spacelike separations. The field algebra and the gauge group are constructed simultaneously from the local observables. There will be sectors obeying parastatistics, an intrinsic notion derived from the observables, if and only if the gauge group is non-Abelian. Topological charges would manifest themselves in field operators associated with spacelike cones but not localizable in bounded regions of Minkowski space. No assumption on the particle spectrum or even on the covariance of the theory is made. However the notion of superselection sector is tailored to theories without massless particles. When translation or Poincare covariance of the vacuum sector is assumed, our construction leads to a covariant field algebra describing all covariant sectors.
451 citations
TL;DR: In this article, the authors conducted a controlled multicenter trial with central randomization and evaluation of events under blind conditions involving 652 patients with unstable angina, where patients were treated either with conventional therapy alone (group C) (n = 338) or with traditional therapy combined with an inhibitor of platelet aggregation, ticlopidine 250 mg b.i.d. (group T + T), and the primary end points, vascular death and nonfatal myocardial infarction, were observed in 13.6% of the patients in group C and
Abstract: We conducted a controlled multicenter trial with central randomization and evaluation of events under blind conditions involving 652 patients with unstable angina. Patients were treated either with conventional therapy alone (group C) (n = 338) or with conventional therapy combined with an inhibitor of platelet aggregation, ticlopidine 250 mg b.i.d. (group C + T) (n = 314). Patients were assigned randomly within 48 hours of admission and followed up for 6 months. With the "intention-to-treat" approach, the primary end points, vascular death and nonfatal myocardial infarction, were observed in 13.6% of the patients in group C and in 7.3% of the patients in group C + T, which is a reduction in risk of 46.3% (p = 0.009). Vascular mortality was 4.7% in patients in group C and 2.5% in patients in group C + T, which is a reduction in risk of 46.8% (p = 0.139). The risk of nonfatal myocardial infarction was reduced by 46.1% (p = 0.039), with a frequency of 8.9% in patients in group C and 4.8% in patients in group C + T. New Q wave myocardial infarction occurred with a frequency of 6.8% in patients in group C and 3.8% in patients in group C + T, which is a reduction in risk of 44.1% (p = 0.091). Fatal and nonfatal myocardial infarction was 10.9% in patients in group C and 5.1% in patients in group C + T, which is a reduction in risk of 53.2% (p = 0.006). These findings confirm the importance of platelets in the pathogenesis of unstable angina and the usefulness of antiplatelet treatment for the prevention of cardiovascular events.
373 citations
TL;DR: It is concluded that maintenance treatment with interferon prolongs response and survival in patients with multiple myeloma who have responded to conventional induction chemotherapy.
Abstract: The use of interferon for the induction treatment of multiple myeloma has been shown to be effective in about 20 percent of patients. We studied its effects on long-term survival when it was used for maintenance treatment. Between April 1985 and May 1988, 101 patients with symptomatic multiple myeloma who had had a substantial objective response or a lesser objective response with disappearance of symptoms ("disease stabilization") after 12 courses of induction chemotherapy were randomly assigned to receive recombinant interferon alfa-2b as maintenance therapy (n = 50) or to receive no treatment (n = 51). As of December 1989, 66 of the 101 patients have relapsed (25 given interferon and 41 not treated). The median duration of response (from the time of randomization) was 26 months in the patients given interferon and 14 months in the untreated patients (P = 0.0002). A total of 37 patients have died (14 given interferon and 23 not treated). The median duration of survival (from randomization) was ...
367 citations
TL;DR: The biochemical and histological findings suggest that long-term glucocorticoid therapy causes a reduction of bone turnover, that the bone loss occurs predominantly within the first 6 months of treatment and that patients with lower bone mass have a lower rate of bone loss.
335 citations
TL;DR: In this article, the general characteristics of inelastic proton-antiproton collisions at the CERN SPS Collider were studied with the UA1 detector using magnetic and calorimetric analysis.
295 citations
TL;DR: The results indicate that the dopaminergic system, within the caudate and the accumbens nuclei, is under glutamatergic control through kainate and quisqualate receptors, while the NMDA receptors do not appear to be involved.
264 citations
TL;DR: A regulatory role for basic fibroblast growth factor is suggested in early hematopoiesis, which requires not only the stimulatory effect of interleukin-3, granulocyte-macrophage colony-stimulating factor, and erythropoietin, but also the permissive action of basic fibronectin.
Abstract: Methodology has been developed that enables virtually complete purification and abundant recovery of early hematopoietic progenitors from normal human adult peripheral blood. A fraction of the pure progenitors is multipotent (generates mixed colonies) and exhibits self-renewal capacity (gives rise to blast cell colonies). This methodology provides a fundamental tool for basic and clinical studies on hematopoiesis. Optimal in vitro cloning of virtually pure progenitors requires not only the stimulatory effect of interleukin-3, granulocyte-macrophage colony-stimulating factor, and erythropoietin, but also the permissive action of basic fibroblast growth factor. These findings suggest a regulatory role for this growth factor in early hematopoiesis.
TL;DR: Three groups of subjects, normal controls, right brain damaged patients with and without heminattention, were required to bisect a line in presence of a fixed or a moving background: together with the optokinetic nystagmus, a displacement of the subjective midpoint was observed in all three groups of Subjects.
TL;DR: In this paper, the authors present the results of research carried out on the paleogeographic and geodynamic post-collisional evolution of the peri-Tyrrhenian area from the Southern Alps to Sicily.
TL;DR: In this article, the three-point euclidean correlation functions were studied and a theorem relating their asymptotic behaviour in euclidic time and for infinite space volume to the threshold time-like form factor and the scattering length was derived.
TL;DR: It is demonstrated that antigen-specific B cells can efficiently deliver HBenvAg to the class I pathway, presenting its fragments to class I-restricted cytotoxic T lymphocytes (CTLs) which kill the specific B cells, a mechanism of suppression of neutralizing anti-hepatitis B virus (HBV) antibody response.
Abstract: Specific B lymphocytes can act as very efficient antigen-presenting cells. They bind antigen with high affinity via their immunoglobulin receptors, process it through the class II major histocompatibility complex (MHC) pathway, and present its fragments to class II-restricted T lymphocytes. In general, exogenous antigens and noninfectious viral particles enter the class II pathway and are selectively associated with class II MHC molecules. The presentation of an exogenous antigen in association with class I molecules has been reported for only a few antigens, including the hepatitis B envelope antigen (HBenvAg). Here we demonstrate that antigen-specific B cells can efficiently deliver HBenvAg to the class I pathway, presenting its fragments to class I-restricted cytotoxic T lymphocytes (CTLs) which kill the specific B cells. This could represent a mechanism of suppression of neutralizing anti-hepatitis B virus (HBV) antibody response, a phenomenon that accompanies the development of the chronic HBV-carrier state.
TL;DR: It is concluded that carnitine uptake studies in cultured skin fibroblasts are important for diagnosis, screening of siblings and heterozygote parents, understanding pathogenesis, and investigating the molecular basis of this disease.
Abstract: Evidence is emerging that primary systemic carnitine deficiency, a potentially lethal but eminently treatable inborn error of fatty acid oxidation, involves a cellular defect in the uptake of carnitine We present four unrelated children with primary carnitine-responsive cardiomyopathy, weakness (with or without hypoketotic hypoglycemic encephalopathy), low serum and/or tissue carnitine concentrations, and severe renal carnitine leak Di-carboxylic acids were absent in the urine of three children who were tested, and all four had a rapid and dramatic improvement in cardiac function, strength, and somatic growth after carnitine therapy We studied carnitine uptake in cultured skin fibroblasts from all four children and seven of the eight healthy nonconsanguinous parents [3H]L-car-nitine uptake was evaluated in vitro under linear time kinetics Substrate concentrations were varied from 01 to 1000 μM Physiologic uptake was determined at carnitine concentrations between 01 and 50 μM Nonspecific uptake was determined at a concentration of 10 mM The four patients had negligible uptake throughout the physiologic range, implying a marked deficiency in the specific high-affinity, low-concentration, carrier-mediated uptake mechanism At a concentration of 5 μmol/L, the mean velocity of uptake in the four patients was 2% of control values Their parents showed intermediate maximal rates of carnitine uptake ranging from 13 to 44% of control Vmax values, but normal Km values, suggesting that the hetero-zygotes had a reduced number of normal functioning carnitine transporters The observed reduction in Vmax values for the parents supports an autosomal recessive inheritance pattern and may be a more sensitive indicator of heterozygosity than serum carnitine concentrations We conclude that carnitine uptake studies in cultured skin fibroblasts are important for diagnosis, screening of siblings and heterozygote parents, understanding pathogenesis, and investigating the molecular basis of this disease Given the frequent history of previously unexplained sibling deaths in these familes, early identification of presymptomatic siblings and oral institution of carnitine prophylaxis may decrease immediate and long-term morbidity and mortality
TL;DR: A system to query databases using diagrams as a standard user interface that makes use of a conceptual data model, a query language on this model, and a graphical user interface is proposed.
Abstract: A system to query databases using diagrams as a standard user interface is proposed. The system, called Query by Diagram* (QBD*), makes use of a conceptual data model, a query language on this model, and a graphical user interface. The conceptual model is the entity-relationship model. The query language, whose expressive power allows recursive queries, supports visual interaction. The main characteristics of the interface are ease of use and the availability of a rich set of primitives for schema selection and query formulation. The expressive power of QBD* and G/sup +/, which are the only languages allowing recursive queries to be expressed graphically are compared. >
TL;DR: In this article, the impact of financial structures on industrial dynamics was investigated and it was argued that specific financial set-ups -such as market-based and credit-based mechanisms of allocation, control and ownership transfer - are likely to exert different influences on the rates and modes of industrial innovation.
Abstract: This paper investigates the impact financial structures upon industrial dynamics whenever the system is permanently characterized by unexploited opportunities for innovation, (highly) ‘bounded’ rationality and trial-and-error search processes. In these circumstances, it is argued, specific financial set-ups - such as ‘market-based’ vs. ‘credit-based’ mechanisms of allocation, control and ownership transfer - are likely to exert different influences on the rates and modes of industrial innovation. Relatedly, one suggests some hypotheses on the links between financial systems and features of industrial evolution, and some tentative taxonomies.
TL;DR: A strict spatial and functional correlation can be inferred between DAO and POD in chick-pea, and probably in other Leguminosae species, in accordance with previous evidence indicating an integrated role for these enzymes in the apoplast.
Abstract: The activities of diamine oxidase (DAO, EC 1.4.3.6) and peroxidase (POD, EC 1.11.1.7) were determined along the stems of light-grown Cicer arietinum L. (chick-pea) seedlings. Enzyme activities were evaluated in the soluble, lightly bound (salt extraction) and tightly bound (Driselase digestion) wall fractions, and in residual fractions obtained from the different internodes. Apparent tissue distributions of both enzymes and lignin depositions were visualised by means of histochemical and immunohistochemical techniques. A close relationship was found between DAO and POD activities in the soluble and wall fractions along the stem. The biochemical activities of both enzymes decreased from the base to the apex of the stem in parallel with the distribution pattern of lignifying tissues in this organ. A similar activity gradient was found for each enzyme along the epidermis of the whole organ. Moreover, deetiolation elicited a rise in the activities of both enzymes in this tissue. Wounding chick-pea stems induced parallel increases in DAO and POD activities in the soluble and wall fractions. In-situ histochemical detection of both enzymes demonstrated the parallel occurrence of the DAO/POD system and lignosuberised depositions in the cell walls adjacent to the wound site. The patterns of POD isoforms resulting from the wound-healing process were determined by means of starch-gel electrophoresis. In addition to changes in relative intensity of enzyme bands in soluble and wall fractions, a new POD isoform, possibly related to the wounding response, appeared in the soluble fraction. This isoform was shown to be lightly bound to cell walls as it could be detected in the extracellular fluids obtained from wound-healed seedlings. On the basis of the above-mentioned results, a strict spatial and functional correlation can be inferred between DAO and POD in chick-pea, and probably in other Leguminosae species, in accordance with previous evidence indicating an integrated role for these enzymes in the apoplast.
TL;DR: The slow relaxation phase observed in temperature-jump experiments carried out on equilibrium mixtures of wild-type azurin and cytochrome c551 was definitively shown to be due to a conformational relaxation involving His35.
Abstract: The electron-transfer reactions of site-specific mutants of the blue copper protein azurin from Pseudomonas aeruginosa with its presumed physiological redox partners cytochrome c551 and nitrite reductase were investigated by temperature-jump and stopped-flow experiments. In the hydrophobic patch of azurin Met44 was replaced by Lys, and in the His35 patch His35 was replaced by Phe, Leu and Gln. Both patches were previously thought to be involved in electron transfer. 1H-NMR spectroscopy revealed only minor changes in the three-dimensional structure of the mutants compared to wild-type azurin. Observed changes in midpoint potentials could be attributed to electrostatic effects. The slow relaxation phase observed in temperature-jump experiments carried out on equilibrium mixtures of wild-type azurin and cytochrome c551 was definitively shown to be due to a conformational relaxation involving His35. Analysis of the kinetic data demonstrated the involvement of the hydrophobic but not the His35 patch of azurin in the electron transfer reactions with both cytochrome c551 and nitrite reductase.
TL;DR: The frequency of myocardial infarction and sudden death is increased between 6 AM and noon, and the identification of periods of high risk for vascular events may have important therapeutic implications, such as matching drug effects with vulnerability.
Abstract: The frequency of myocardial infarction and sudden death is increased between 6 AM and noon. To determine whether the same is true for the onset of ischemic stroke, we studied 426 consecutive patients within 12 hours after the onset of their first hemispheric stroke. The frequency of onset of hemispheric stroke was significantly (p = 0.0001) higher from 6:01 AM to noon (56.1%) than from 12:01 PM to 6 PM (20.2%), from 6:01 PM to midnight (8.2%), and from 12:01 AM to 6 AM (15.5%). The identification of periods of high risk for vascular events may have important therapeutic implications, such as matching drug effects with vulnerability.
TL;DR: The authors' analysis of the significant prognostic features of LDGL may help in understanding the heterogeneous nature of this syndrome.
Abstract: Lymphoproliferative disease of granular lymphocytes (LDGL) is a recently recognized, relatively rare atypical lymphocytosis characterized by the presence of over 2000 lymphocytes with cytoplasmic azurophilic granules/mm3 in the peripheral blood. The clinical course is heterogeneous, varying from spontaneous regression to progressive, malignant disease. As a consequence, clinical intervention is not standardized. In a worldwide multicenter study, the authors observed 151 patients with LDGL for a mean follow-up time of 29 months. Forty-three patients were asymptomatic at the time of diagnosis. In the remaining cases, clinical symptoms included fever (41 cases), infections (58), neutropenia (47), anemia (17), and thrombocytopenia (12). In 69 cases, LDGL coexisted with an associated disease. Most patients had a nonprogressive clinical course despite the presence of severe symptoms. In 19 patients, death related to LDGL occurred within 48 months. The authors investigated which features at diagnosis were significantly associated with increased mortality. In the univariate analysis, lymph node and liver enlargement, fever at presentation, skin infiltration, a low (less than or equal to 5000/mm3) or high (greater than 20,000/mm3) peripheral leukocyte count, relatively low (less than or equal to 3000) or high (greater than 7000/mm3) absolute peripheral granular lymphocyte (GL) count, and a low (less than or equal to 15%) percentage of HNK-1-positive cells were found to be predictors of increased mortality. In the multivariate analysis, significant independent predictors were fever at diagnosis, a low (less than or equal to 15%) percentage of HNK-1-positive peripheral blood mononuclear cells (PBMC) and a relatively low (less than or equal to 3000) GL count. These results showed that about 25% of the patients with LDGL were diagnosed after a routine blood count and had no clinical symptoms. The remaining patients were symptomatic, with some experiencing a fatal clinical course. The author's analysis of the significant prognostic features of LDGL may help in understanding the heterogeneous nature of this syndrome.
TL;DR: In this paper, the explicit form of the probability law and the associated flow function of a random motion governed by the telegraph equation are derived and connections of this law with the transition function of Brownian motion are explored.
TL;DR: In cirrhotic patients, the oxidation of endogenous fat is the main contributor to basal energy production rate, and a significant correlation was present between fat oxidation and plasma free fatty acid levels, which confirms that the prevalent fat use in cirrhosis patients is supported by the greater availability of fat‐derived substrates.
TL;DR: It is suggested that consumption of butter may detrimentally affect coronary risk factors, while polyunsaturated and monounsaturated fats may be associated with a lower coronary risk profile.
Abstract: The cross-sectional association between consumption of various fats (eg, butter, olive oil, and vegetable oil) and risk factors for coronary heart disease was analyzed in a sample of 4903 Italian men and women 20 to 59 years of age. The intake of fats was ascertained by an interviewer-administered questionnaire. Increased consumption of butter was associated with significantly higher blood pressure and serum cholesterol and glucose levels for men; in women only the association with glucose reached statistical significance. In both sexes consumption of olive oil and vegetable oil was inversely associated with serum cholesterol and glucose levels and systolic blood pressure. These findings were adjusted for confounding effects of other risk factors for cardiovascular disease. These cross-sectional findings from a large population sample suggest that consumption of butter may detrimentally affect coronary risk factors, while polyunsaturated and monounsaturated fats may be associated with a lower coronary risk profile. (JAMA. 1990;263:688-692)
TL;DR: The results indicate that the oocyte factor(s) and TGF-beta 1 are not the same and that they operate through different receptors in stimulating HA synthesis.
TL;DR: In this article, the authors retrospectively studied epidemiologic, clinical, pathologic, and microbiologic features of this infection during a 68-month period at the Division of Hematology of the University La Sapienza in Rome.
Abstract: Blastoschizomyces capitatus (formerly named Trichosporon capitatum or Geotrichum capitatum) is a rare cause of invasive fungal disease in immunocompromised hosts. We retrospectively studied epidemiologic, clinical, pathologic, and microbiologic features of this infection during a 68-month period at the Division of Hematology of the University La Sapienza in Rome. Twenty patients with evidence of B. capitatus were identified: 12 were infected, four were possibly infected, and four had evidence of B. capitatus colonization but were not infected by this fungus. Pulmonary infiltrates were seen in seven infected patients; four of these patients eventually developed mycetomalike cavitations. Eight infected patients presented clinical and radiologic features of focal hepatitis compatible with hepatosplenic candidiasis. Of the 12 infected patients, two did not receive any antifungal treatment and died, five did not show any response to systemic antifungal therapy, and five received prolonged amphotericin B plus 5-fluorocytosine therapy. Of the last group, three patients achieved stable remission of their acute leukemia and were cured, and two improved but had an apparent relapse of B. capitatus infection after their acute leukemia recurred.
TL;DR: The crystal structure of the ferric form of myoglobin from the mollusc Aplysia limacina has been refined at 1.6 A resolution, by restrained crystallographic refinement methods, and indicates that a hydroxyl ion is bound to the Fe sixth co-ordination position.
TL;DR: Evidence is provided that early evaluation of cerebral blood flow with single-photon emission computed tomography is useful to detect subgroups of patients with different clinical outcomes during the acute phase of ischemic stroke.
Abstract: We investigated 32 patients with completed ischemic stroke less than or equal to 6 hours after the onset of symptoms by means of computed tomography, cerebral angiography, and technetium-99m-labeled hexamethylpropyleneamine oxime single-photon emission computed tomography to study cerebral blood flow. Follow-up computed tomography and cerebral blood flow studies were performed 1 week and 1 month after admission. Poor outcome at 1 month was evident in 18 (78%) of the 23 patients with severe neurologic deficit on admission and in 11 (92%) of the 12 patients with severe hypoperfusion in the affected hemisphere on admission. All 10 patients with severe impairment of both neurologic status and cerebral blood flow had a poor outcome at 1 month. We detected severe hypoperfusion in patients with large lesions on computed tomograms or cerebral artery occlusions on angiograms. Cerebral blood flow had increased at the 1-week follow-up despite different clinical outcomes. Our data provide evidence that early evaluation of cerebral blood flow with single-photon emission computed tomography is useful to detect subgroups of patients with different clinical outcomes during the acute phase of ischemic stroke.