Successful initiation and maintenance of hemodialysis in an adult patient with complete transposition of the great arteries

Cyanotic congenital heart disease (CCHD) is a life-threatening cardiac defect that requires palliative or corrective surgery in early life. Major advances in medical and surgical management have resulted in the survival of CCHD patients to adulthood with or without corrective surgery, though some are at risk of development of end-stage renal disease (ESRD) due to cyanotic nephropathy (CN). There is little or no information on the initiation and maintenance of hemodialysis (HD) in such patients. We present here a case of a 44-year-old man with complete transposition of the great arteries and CN-related ESRD. He had only received a bi-directional Glenn’s operation and still suffered persistent severe hypoxemia and impaired cardiac function. ESRD was successfully treated with HD over more than 4 years. The case emphasizes the need for special attention in the selection and initiation of renal replacement therapy.     

Decrease in acetylcholinergic neurons in the pedunculopontine tegmental nucleus in a patient with Prader‐Willi syndrome

Prader‐Willi syndrome (PWS) is caused by the absence of paternally contributed genes in chromosome 15, and is characterized by hypotonia, feeding difficulty, mental retardation, growth failure, hypogonadism and severe obesity. To elucidate the pathogenesis of neurological disorders, we immunohistochemically examined the γ‐aminobutyric acid (GABA)ergic interneurons (GABAis) in the cerebral cortex and acetylcholine neurons (AchNs) in the nucleus basalis of Meynert (MyN) and pedunculopontine tegmental nucleus pars compacta (PPNc) in an autopsy case of one PWS patient with a deletion in the 15q11‐q12 region and three control patients. The GABAis in the cerebral cortex and AchNs in the MyN were well preserved in the PWS patient. The AchNs in the PPNc in the PWS patient were severely reduced in comparison with those in controls, whereas catecholaminergic neurons and GABAis were preserved. The selective loss of AchNs in the PPNc may be involved in hypotonia and/or REM sleep abnormalities in PWS patients.     

The role of chaotic resonance in cerebellar learning

According to the cerebellar learning hypothesis, the inferior olive neurons, despite their low firing rates, are thought to transmit high-fidelity error signals to the cerebellar cortex. “Chaotic resonance”, via moderate electrical coupling between inferior olive neurons, has been proposed to realize efficient transmission of the error signal by desynchronizing spiking. Here, we first show that chaotic resonance is a robust phenomenon, as it does not depend upon the details of the inferior olive neuronal model. Second, we show that chaotic resonance enhances learning of a neural controller for fast arm movements. Furthermore, when both coupling and noise are considered simultaneously, we found that chaotic resonance widens the range of noise intensity within which efficient learning can be realized. We suggest that, from an energetic viewpoint, the spiking activity induced by chaos can be more economical than that induced by noise.     

Effects of early tooth extractions on hippocampal GFAP-positive cells in aged senescence-accelerated mice

The effects of early tooth extractions on age-associated changes in cognitive function were evaluated. Specifically, teeth were extracted at an early age in senescence-accelerated mice (SAM)P8, and the number of glial fibrillary acid protein (GFAP)-positive astrocytes and spatial perception were evaluated at young, mature, and old ages. The following results were obtained:1. Concerning spatial perception evaluated by the Morris water maze test, the shortening of the time until the animals reached the platform was significantly slower in mature or old mice of the tooth extraction group compared with age-matched controls. However, no significant difference was noted in the rate of shortening in young mice between the tooth extraction and control groups.2. The number of GFAP-positive cells was significantly higher in the CA3 region of the hippocampus in the mature or old mice of the tooth extraction group compared with age-matched controls. However, no significant difference was observed in the CA1 and dentate gyrus (DG) region of the hippocampus in the mature or old mice and in the CA1, CA3, and DG region in the young mice between the two groups.These results suggest that the loss of teeth at an early age accelerated aging and that GFAP-positive astrocytes increased to compensate for a decrease in pyramidal cells.     

Atomic force microscopic measurement of the mechanical properties of intact endothelial cells in fresh arteries

Mechanical properties of living endothelial cells in the abdominal aortas and in the medial and lateral wall of aortic bifurcations obtained from rabbits were determined by means of an atomic force microscope (AFM), focusing on the locational differences. Force (F)-indentation (δ) curves of the cells were expressed by an exponential function: F=a(exp(bδ)−1), where a and b are constants. The parameters b and c(=ab) represent the rate of modulus change and initial modulus, respectively. The slope of F-δ curves a and the parameter c were higher in the medial wall than in the other sites, which is attributable to abundant stress fibres in endothelial cells in the medial wall. There were no differences in the parameter b among the three locations. These results indicate that endothelial cells are stiffer in the medial wall of aortic bifurcation than in the other regions.     

MRI-based preplanning in low-dose-rate prostate brachytherapy

PURPOSE: To compare the dosimetric results between MRI-based and TRUS-based preplanning in permanent prostate brachytherapy, and to estimate the accuracy of MRI-based preplanning by comparing with CT/MRI fusion-based postimplant dosimetry. METHODS AND MATERIALS: Twenty-one patients were entered in this prospective study with written informed consent. MRI-based and TRUS-based preplanning were performed. The seed and needle locations were identical according to MRI-based and TRUS-based preplanning. MRI-based and TRUS-based preplanning were compared using DVH-related parameters. Following brachytherapy, the accuracy of the MRI-based preplanning was evaluated by comparing it with CT/MRI fusion-based postimplant dosimetry. RESULTS: Mean MRI-based prostate volume was slightly underestimated (0.73 cc in mean volume) in comparison to TRUS-based volume. There were no significant differences in the mean DVH-related parameters except with rectal V(100)(cc) between TRUS-based and MRI-based preplanning. Mean rectal V(100)(cc) was 0.74 cc in TRUS-based and 0.29 cc in MRI-based preplanning, respectively, and the values demonstrated a statistical difference. There was no statistical difference in mean rectal V(150)(cc), and rectal V(100)(cc) between MRI-based preplanning and CT/MRI fusion-based postimplant dosimetry. CONCLUSION: Prostate volume estimation and DVH-related parameters in MRI-based preplanning were almost identical to TRUS-based preplanning. From the results of CT/MRI fusion-based postimplant dosimetry, MRI-based preplanning was therefore found to be a reliable and useful modality, as well as being helpful for TRUS-based preplanning. MRI-based preplanning can more accurately predict postimplant rectal dose than TRUS-based preplanning.