A distal anterior cerebral artery aneurysm in infant: disappearance and reappearance of the aneurysm.

The incidence of intracranial aneurysms in childhood is rare, especially in infancy. Spontaneous thrombosis of a cerebral aneurysm in a child is very rare, particularly in a non-giant aneurysm. We report a case of a 1-month-old girl with a distal anterior cerebral artery aneurysm which disappeared spontaneously after subarachnoid hemorrhage and reappeared 6 months later. Surgical resection of the aneurysm was performed and she discharged uneventfully 10 days later. Histological examination revealed an aneurysm with a fibrous muscular layer, absence of the internal elastic lamina and partial hypertrophy of the intimal layer. Though the pathogenesis of this aneurysm is uncertain, two hypotheses are discussed.     

Estimation of the following cardiac output using sympathetic tone and hemodynamics for the control of a total artificial heart.

A sympathetic neurogram is potentially useful for the development of a real time total artificial heart (TAH) control system. We used sympathetic tone and hemodynamic derivatives to estimate the following cardiac output in acute animal experiments using adult mongrel dogs. Moving averages of the mean left atrial pressure and mean aortic pressure were used as parameters of the preload and afterload, respectively. Renal sympathetic nerve activity (RSNA) was employed as a parameter of sympathetic tone. Equations for the following cardiac output were calculated using multiple linear regression analysis of the time series data. A significant correlation was observed between the estimated and following measured cardiac output. These results suggest the potential usefulness of the sympathetic neurogram for the real time TAH automatic control system.     

Mayer waves in dogs with total artificial heart.

To assess the effect of a total artificial heart (TAH) on the autonomic nervous system a power spectral analysis of the hemodynamics in a TAH animal was done by the maximum entropy method. Two pneumatically driven sac-type ventricular assist devices were implanted as total biventricular bypass (BVB) in adult mongrel dogs to compare the differences between natural heart and TAH. Once the BVB was pumping, the natural heart was electrically fibrillated to constitute the BVB-type TAH model. In the arterial pressure waveform in animals with TAH, respiratory waves were not changed (97.7 +/- 24.6%) though Mayer waves were significantly decreased (47.5 +/- 22.6%) compared with the animal with a natural heart. These results suggest that prosthetic hemodynamics in the TAH animal affect fluctuations in the cardiovascular system.     

Chronic inflammatory demyelinating polyradiculoneuropathy associated with multifocal nerve hypertrophy--report of a case with MRI study]

We reported a 29-year-old woman who had chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) associated with multifocal nerve hypertrophy. She developed chronic progressive muscular weakness of distal part of her extremities and sensory ataxia of limbs and trunk for five years. Steroid therapy improved most of her signs and symptoms. No recurrence has occurred for the subsequent four years until present time. Magnetic resonance imaging (MRI) revealed multifocal and nodular hypertrophy of her peripheral nerves in the extremities. MRI also detected the hypertrophy of posterior nerve ganglia and extradural nerve roots. Hypertrophic nerve trunk comprised of multifocal and nodular hypertrophy of the nerve fiber fascicles which were detected as abnormal high signal intensity area in MR T2-weighted images. Her sural nerve contained no onion-bulb formations and presented normal low signal in MR T2-weighted images. We concluded that the hypertrophic changes occurred multifocally in and among nerve fascicles predominantly at the proximal part of the nerves of the extremities. MRI is useful method to detect the hypertrophic change of peripheral nerves deep in the trunk and the extremities in CIDP.     

Cardiac-related sympathetic nerve activity during circulation with only the left ventricular assist device.

Circulatory maintenance with a left ventricular assist device (LVAD) alone during cardiac arrest until heart transplantation has been evaluated. To assess the effect on the autonomic nervous system, the sympathetic neurogram was analyzed by power spectrum and coherence function. LVAD were inserted between the left atrium and the descending aorta in seven adult mongrel dogs and ventricular fibrillation was induced electrically. Renal sympathetic nerve activity (RSNA) was detected by bipolar electrodes attached to the left renal sympathetic nerve. Values of squared coherence between the arterial pulse wave and RSNA were calculated. Under the condition of circulatory maintenance with only LVAD, coherence at the cardiac rhythm frequency was decreased, and coherence at the LVAD pumping rhythm frequency was increased. These results indicate that the arterial pulse wave observed during maintenance of the circulation with only LVAD contributed to the sympathetic neurogram.     

Experimental Study of Physiological Advantages of Assist Circulation Using Oscillated Blood Flow

Abstract: To estimate the effect of oscillated blood flow on hemodynamics in an awake condition, left ventricular assist circulation using oscillated blood flow was performed on 3 adult goats as chronic animal examination. A vibrating flow pump (VFP) was used for generating high-frequency oscillated flow. The blood flow rate of assisted circulation was approximately 1.0 L/min, and the driving frequency of VFP was 25 Hz. Systemic vascular resistance and arterial impedance were calculated in this study. Systemic vascular resistance during assist circulation was decreased compared with that without assistance. Oscillated blood flow may be effective in decreasing vascular resistance. Moreover, it was suggested from the study of arterial impedance that motive characteristics of the vascular wall against changing blood pressure may keep their normal reaction. Therefore, oscillated blood flow may be used for left ventricular assist circulation as concluded from the study of the characteristics of blood vessels.     

Changes in soft palate taste buds of rats due to aging and zinc deficiency--scanning electron microscopic observation

The effects of aging and zinc deficiencies on taste were studied. The soft palate of zinc-deficient old rats, prepared by feeding with a zinc-deficient diet, were studied by a light microscope and a scanning electron microscope, and comparative examination was made on the morphological changes in soft palate papillae and taste buds of young normal rats and control old rats. In the case of young normal rats, papillae similar to lingual fungiform papillae were observed on the soft palate; one taste bud per one papilla was observed. The papillae were concentrated in the central area of the soft palate continuing from the hard palate. In the case of old rats, decrease in the number of papillae, flattening of papillae, exfoliation and atrophy of mucosal epithelium and leveling of microplicae were observed. In the case of zinc-deficient old rats, the above-mentioned tendencies were more significant. While dense substance and microvilli were observed in taste pores of taste buds of young normal rats, these were found to decrease or disappear in the zinc-deficient old rats.     

Specific Reduction of Toxic Side Effects of Adriamycin by Induction of Metallothionein in Mice

The effect of preinduction of metallothionein (MT) by bismuth (Bi) compounds on the toxic side effects and antitumor activity of adriamycin (ADR) was investigated in mice. Preinduction of MT by oral administration of bismuth subnitrate (BSN) significantly decreased the lethal toxicity, cardiotoxicity and bone marrow toxicity observed with a single subcutaneous injection of ADR. A significant increase in the concentration of cardiac MT was observed in mice treated with BSN. The MT level in the heart was significantly correlated with the protective effect of BSN against the cardiotoxicity of ADR. In tumor-bearing mice, pretreatment with BSN did not affect the antitumor activity of ADR, although its cardiotoxicity was significantly depressed. The ability of BSN to reduce specifically the toxicity of ADR may be ascribed to the fact that Bi induces MT in the target tissue of ADR toxicity but not in a tumor. The protective effect of MT against the toxicity of ADR, which is believed to act as an anticancer agent by generating active oxygen, can be assumed to be due to its ability to scavenge free radicals or inhibit their formation.