Apperceptive agnosia and face recognition

Abstract

Are faces and objects recognized by separate visual recognition systems or might a single system subserve the recognition of both classes of input? Recognition of faces and objects by a single system predicts that prosopagnosics, who selectively lose the ability to recognize faces due to brain damage, should also lose the ability to recognize objects. Contrary to this prediction, case studies of prosopagnosia have reported intact object recognition. Further support for separate visual recognition systems comes from the case of HH reported here. Following a stroke involving the left posterior cortex, HH has a severe apperceptive visual agnosia for visually presented objects and an alexia for words. Yet, he shows relatively spared visual face processing. Such a performance pattern completes a double dissociation between face and object processing when coupled with prosopaganosia. More importantly, HH is the first apperceptive visual object agnosic to demonstrate spared face processing. The severity of his object-processing deficit is such that from the earliest levels in the visual processing hierarchy, distinct neural substrates must be responsible for processing some objects and faces. These results are discussed as support for Farah's model (Visual agnosia: disorders of object recognition and what they tell us about normal vision. Cambridge, MA: MIT Press, 1990) of object, face and word recognition.     

The Pneumonia Etiology Research for Child Health Project: a 21st century childhood pneumonia etiology study

The Pneumonia Etiology Research for Child Health (PERCH) project is a 7-country, standardized, comprehensive evaluation of the etiologic agents causing severe pneumonia in children from developing countries. During previous etiology studies, between one-quarter and one-third of patients failed to yield an obvious etiology; PERCH will employ and evaluate previously unavailable innovative, more sensitive diagnostic techniques. Innovative and rigorous epidemiologic and analytic methods will be used to establish the causal association between presence of potential pathogens and pneumonia. By strategic selection of study sites that are broadly representative of regions with the greatest burden of childhood pneumonia, PERCH aims to provide data that reflect the epidemiologic situation in developing countries in 2015, using pneumococcal and Haemophilus influenzae type b vaccines. PERCH will also address differences in host, environmental, and/or geographic factors that might determine pneumonia etiology and, by preserving specimens, will generate a resource for future research and pathogen discovery.     

Turnover of circulating hematopoietic stem cells

Short-term parabiosis of male and female CBA/CaJ mice was used to investigate the turnover of circulating hematopoietic stem cells. The exchange and subsequent disappearance of donor stem cells were monitored by spleen colony assay and chromosome analysis of individual colonies. The results revealed an exponential disappearance of pluripotent stem cells from blood with a characteristic half time of 1.7 h. Blood-borne stem cells were shown to be equilibrated with a subpopulation of marrow stem cells exhibiting a disappearance half time of 9.5 h. Splenectomy did not change the apparent rate of stem cell removal from the blood.     

Plasma levels of plasminogen activator inhibitor type 1, beta- thromboglobulin, and fibrinopeptide A before, during, and after treatment of acute myocardial infarction with alteplase

Plasma levels of plasminogen activator inhibitor type-1 (PAI-1), beta- thromboglobulin (beta TG), and fibrinopeptide A (FPA) were followed over 24 hours in 30 patients treated with alteplase for acute myocardial infarction. Samples were taken at baseline (T Oh), after 90 minutes (under alteplase, no heparin, T 1.5h), after 120 minutes (under alteplase and heparin, T 2h), 30 minutes after thrombolytic therapy (T 3.5h), as well as 12 hours (T 12h) and 24 hours (T 24h) after baseline. PAI-1 antigen levels (55 +/- 9 ng/mL at T Oh, mean +/- SEM) decreased to 35 +/- 5 (T 1.5h) and 40 +/- 6 (T 2h) ng/mL under alteplase, before increasing to 84 +/- 22 (T 3.5h), 130 +/- 30 (T 12h), and 64 +/- 7 (T 24h) ng/mL after therapy, P less than .001. A high baseline PAI-1 activity (18 +/- 3 ng/mL) decreased to 2.0 +/- 0.4 (T 1.5h) and 1.7 +/- 0.2 (T 2h) under alteplase and increased to 32 +/- 5 (T 12h) and 19 +/- 3 (T 24h) ng/mL after therapy (P less than .0001). beta TG levels (339 +/- 105 ng/mL at T Oh) decreased to 203 +/- 48 (T 2h), 154 +/- 51 (T 3.5h), 187 +/- 40 (T 12h), and 142 +/- 32 (T 24h) ng/mL under heparin (P less than .01). FPA levels (34 +/- 9 ng/mL at T Oh) increased to 85 +/- 15 ng/mL under alteplase alone (T 1.5h) and normalized under heparin (11 +/- 4, 6 +/- 2, 4 +/- 2, and 3 +/- 1 ng/mL at T 2h, T 3.5h, T 12h, and T 24h, respectively). A high level of FPA at T 3.5h correlated with reocclusion (33 +/- 12 ng/mL, n = 4 v 2.9 +/- 0.5 ng/mL, n = 21, P less than .005). We conclude that plasma levels of PAI- 1 antigen as well as activity markedly increase after alteplase therapy of acute myocardial infarction. The high activity of PAI-1 and decreasing beta TG levels suggest that platelets do not contribute significantly to this phenomenon. The marked increase of FPA levels under recombinant tissue-type plasminogen activator alone and its normalization under heparin emphasize the important role of concomitant anticoagulation in controlling further intravasal fibrin generation under alteplase.     

Effect of atrioventricular synchrony on stroke volume during ventricular tachycardia in man.

The hemodynamic consequences of atrioventricular (AV) synchrony during ventricular tachycardia were evaluated during cardiac electrophysiologic testing. The relationship between stroke volume and the AV interval was investigated on a beat-by-beat basis in six patients during induced monomorphic ventricular tachycardia. Stroke volume was calculated either (1) in the right ventricle using impedance catheter method (four patients) or (2) in the left ventricle using Doppler measurement of aortic blood velocity (two patients). The impedance catheter method underestimated stroke volume by a factor of 4.2 +/- 2.4 compared with the thermodilution cardiac output method. However, there was a highly linear relationship between both methods for computing stroke volume (r greater than 0.9). Five patients had complete AV dissociation during ventricular tachycardia, and different AV intervals spanned the entire tachycardia cycle lengths. Largest stroke volumes were associated with optimal AV intervals within 120 and 230 msec, resulting in a 97 +/- 59% increase in stroke volume over ventricular tachycardia cycles not associated with atrial activity. Customized atrial pacing during ventricular tachycardia may provide a valuable means for artificially establishing the hemodynamically optimal AV interval and eliminating the ventricular tachycardia cycles not preceded by atrial activity.     

Long-term endocardial atrial pacing in children with postoperative bradycardia-tachycardia syndrome and limited ventricular access

Permanent pacing in children, including those with postoperative bradycardia-tachycardia syndrome, has been compromised by the availability of pulse generators, electrode leads and implantation techniques designed for the adult patient. Recent technologic improvements and simplified implantation techniques have reduced many of these barriers and have made endocardial as well as epicardial ventricular pacing more feasible. However, in some children, ventricular pacing may be impeded by anatomic abnormalities due to congenital anomalies or prior cardiac operations. In these instances, endocardial atrial pacing may provide an alternative therapeutic approach in selected patients. This report describes the use of endocardial atrial demand pacing in four children with postoperative bradycardia-tachycardia syndrome and restricted ventricular access. This approach controls symptomatic bradycardia, helps prevent and convert paroxysmal intraatrial tachycardia and overcomes the problem of limited ventricular access.     

High-dose radioimmunotherapy versus conventional high-dose therapy and autologous hematopoietic stem cell transplantation for relapsed follicular non-Hodgkin lymphoma: a multivariable cohort analysis

We performed a multivariable comparison of 125 consecutive patients with follicular lymphoma (FL) treated at our centers with either high-dose radioimmunotherapy (HD-RIT) using 131I-anti-CD20 (n = 27) or conventional high-dose therapy (C-HDT) (n = 98) and autologous hematopoietic stem cell transplantation. The groups were similar, although more patients treated with HD-RIT had an elevated pretransplantation level of lactate dehydrogenase (41% versus 20%, P =.03) and elevated international prognostic score (41% versus 19%, P =.02). Patients treated with HD-RIT received individualized therapeutic doses of 131I-tositumomab (median, 19.7 GBq [531 mCi]) to deliver 17 to 31 Gy (median, 27 Gy) to critical organs. Patients treated with C-HDT received total body irradiation plus chemotherapy (70%) or chemotherapy alone (30%). Patients treated with HD-RIT experienced improved overall survival (OS) (unadjusted hazard ratio [HR] for death = 0.4 [95% confidence interval (95% CI), 0.2-0.9], P =.02; adjusted HR, 0.3, P =.004) and progression-free survival (PFS) (unadjusted HR =.6 [95% C.I., 0.3-1.0], P =.06; adjusted HR, 0.5, P =.03) versus patients treated with C-HDT. The estimated 5-year OS and PFS were 67% and 48%, respectively, for HD-RIT and 53% and 29%, respectively, for C-HDT. One hundred-day treatment-related mortality was 3.7% in the HD-RIT group and 11% in the C-HDT group. The probability of secondary myelodysplastic syndrome/acute myeloid leukemia (MDS/AML) was estimated to be.076 at 8 years in the HD-RIT group and.086 at 7 years in the C-HDT group. HD-RIT may improve outcomes versus C-HDT in patients with relapsed FL.