The value and limitation of resting 201Tl reinjection after stress-redistribution imaging for the assessment of myocardial viability: comparison with wall motion improvement by revascularization]

Clinical value and limitation of resting reinjection of small dose of thallium (37 MBq) for the assessment of myocardial viability were evaluated. The results were compared with the degree of wall motion improvement by revascularization to infarcted myocardium supplied by chronic total vessels in 12 patients with old myocardial infarction. Thallium uptake was visually scored and judged as normal, reversible defect (Group 1), new fill in after reinjection (Group 2A), and no fill in even after reinjection (Group 2B). Among 53 segments with initial perfusion abnormality, 21 segments reverted to almost normal, while 32 segments remained abnormal on redistribution images. New fill in after reinjection was observed in 11 segments of 32 segments showing persisting defect on stress and delayed image (37%). Wall motion score index of Group 2A improved significantly higher than Group 2B (p less than 0.01) and almost equal to Group 1, suggesting the utility of reinjection for the assessment of tissue viability which may be underestimated by conventional imaging. But significant wall motion improvement (greater than or equal to 0.6 mean SD/chords) was observed in 6 segments (29%) of 21 segments showing neither redistribution nor fill in after reinjection. These data indicate that small dose of thallium reinjection may enhance detection of viable but jeopardized myocardium, although some underestimation of viability remained to be resolved.     

Difference in central projection of primary afferents innervating facial and intraoral structures in the rat

Transganglionic transport of horseradish peroxidase-wheat germ agglutinin conjugate was used to study the central projection of primary afferent neurons innervating facial and intraoral structures. The examined primary neurons innervating the facial structures were those comprising the frontal and zygomaticofacial nerves and those innervating the cornea, while the primary neurons innervating the intraoral structures included those innervating the mandibular incisor and molar tooth pulps and those comprising the palatine nerve. The primary afferents innervating the facial structures project to the lateral or ventral parts of the trigeminal principal, oral and interpolar subnuclei, and to the rostral cervical spinal dorsal horn across laminae I through V, with a greater proportion being directed to the spinal dorsal horn. The primary afferents innervating the intraoral structures terminate in the dorsomedial subdivisions of the trigeminal principal, oral and interpolar subnuclei, and in laminae I, II, and V of the medial medullary dorsal horn, with a much denser projection being distributed to the rostral subnuclei. In addition to the above brain stem trigeminal sensory nuclear complex, they project to the supratrigeminal nucleus, caudal solitary tract nucleus, and paratrigeminal nucleus. These observations agree with previously reported data that the central projection of trigeminal nerve is organized in different manners for the facial and intraoral structures. Furthermore, the present findings in conjunction with our previous studies clarify that the central projection of primary afferents from the facial skin is organized in a clear somatotopic fashion and that the terminal fields of primary afferents from the intraoral structures extensively overlap in the brain stem trigeminal nuclear complex particularly in its rostral subdivisions. The central mechanism of trigeminal nociception is discussed with particular respect to its difference between the facial and intraoral structures.     

Gorog Thrombosis Test: analysis of factors influencing occlusive thrombus formation.

We used the Gorog Thrombosis Test to analyze the factors influencing the occlusion time, which represents platelet activation and subsequent occlusive thrombus formation, in 132 healthy Japanese volunteers (116 men, 16 women; mean age, 45.0 +/- 12.0 years). The Gorog Thrombosis Test was designed to evaluate platelet aggregation and thrombolytic activity under a high shear stress condition (175 dynes/cm) in a native blood sample in vitro. The mean +/- SD occlusion time was 154.8 +/- 64.7 s (men, 153.4 +/- 64.2 s and women, 165.4 +/- 56.5 s). The occlusion time was inversely correlated with von Willebrand factor ristocetin cofactor activity (VWF:Rco) (r = -0.242, P = 0.0055) and von Willebrand factor antigen (r = -0.230, P = 0.0080). The mean occlusion time in the group with VWF:Rco of at least 170% (137 s) was significantly shorter than that in the group with VWF:Rco less than 170% (156 s, P < 0.05). Platelet counts, other coagulation markers and smoking showed no significant correlations with occlusion time. Red blood cells (r = -0.177, P = 0.0365), hemoglobin (r = -0.191, P = 0.0245) and hematocrit (r = -0.182, P = 0.0329) also showed inverse correlations with the occlusion time. This report is the first to clearly demonstrate the role of von Willebrand factor in the formation of occlusive thrombi in the Gorog Thrombosis Test.     

Intracerebral distribution of albumin after transient cerebral ischemia: light and electron microscopic immunocytochemical investigation

Summary The blood-brain barrier breaks down following cerebral ischemia, but the exact sequence of events for extravasation of serum proteins and their parenchymal distribution remain uncertain. We studied the distribution of serum albumin in the hippocampus of the gerbil brain using light and electron microscopic immunocytochemical techniques. With light microscopy, there was no reaction for albumin for the first 12 h after unilateral common carotid artery occlusion for 10 min and reperfusion. At 12 h, the reaction was weak and limited to the neuropil in the subiculum-CA1 region (between the subiculum and the medial CA1 region). After 24 h, the reaction became intense in the neuropil and neuronal perikarya in the subiculum-CA1 and medial CA1 regions. The electron microscopic immunocytochemical study of the subiculum-CA1 and medial CA1 regions revealed electron-dense immunoprecipitates in the extracellular space and the peripheral part of the apical dendrites as early as 30 min after reperfusion and in the astrocytic cytoplasm after reperfusion for 1 h. However, immunoprecipitates were not found in the neuronal perikarya until after reperfusion for 24 h. The present study demonstrated prompt appearance of albumin in the extracellular space of the brain parenchyma after re-establishment of cerebral circulation and prompt accumulation in the peripheral part of the dendrites with spreading to neuronal perikarya, likely in the process of degeneration and death.Supported by the grant NS-06663 from the National Institutes of Health, U. S. Public Health Service     

Fluid-fluid levels in cavernous hemangioma of soft tissue

Five cases of cavernous hemangioma with fluid-fluid levels on magnetic resonance imaging and/or computed tomography are reported. The signal characteristics were those of blood and histological analysis of the fluid-fluid levels showed that they were blood-filled cavities in the tumor. Although this finding itself is not specific, it may help in confirming the diagnosis of cavernous hemangioma.     

Neuropathology of familial tauopathy

Frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP‐17) is a hereditary progressive neurodegenerative disorder. FTDP‐17 was originally defined in Ann Arbor, Michigan, in 1996. Since then, more than 100 families with FTDP‐17 have been described throughout the world, including 18 families identified in Japan. Genetic studies have identified 40 different mutations in the microtubule‐associated protein tau (MAPT) gene. The clinical features of FTDP‐17 are characterized by behavioral, cognitive and motor disturbances that may occur in various combinations and degrees. Neuropathologic examination shows that various degrees of atrophy may be present in the frontal and temporal lobes, basal ganglia, amygdala and hippocampus. All the brains from patients with FTDP‐17 have also shown the presence of tau deposits in neurons and glial cells. Mutations in MAPT may result in the increased splicing of exon 10, leading to 4‐repeat tau depositions in both neurons and glial cells. MAPT mutations outside of exon 10 show 3‐ and 4‐repeat tau deposits, predominantly in neurons with less glial pathology. Neuronal pathology may resemble that of Alzheimer’s disease or Pick’s disease because of the presence of neurofibrillary tangles or Pick‐like bodies, whereas glial pathology may resemble that of progressive supranuclear palsy or corticobasal degeneration because of the presence of coiled bodies, tufted astrocytes or astrocytic plaques. Correlations between genetic mutations and the heterogeneity of clinical and neuropathologic features remain unclear.     

Successful mitral valve repair for active infective endocarditis accompanied by anorexia nervosa

Infective endocarditis of the mitral area accompanied by anorexia nervosa is extremely rare. A 34-year-old Japanese woman presented with high fever and a heart murmur that had developed over the previous 2-month period. Echocardiography revealed mitral regurgitation and vegetation attached to the anterior mitral leaflet, which had markedly prolapsed to the left atrium. We removed the vegetation with a small part of the anterior mitral leaflet and successfully repaired the mitral valve. The patient showed good recovery, and the mitral regurgitation and left ventricular chamber size had satisfactorily decreased at 2 months after the operation.