Subsequent to cardiac arrest, a 58-year-old man with intractable dysrhythmia and severe arteriosclerosis developed flaccid paraplegia, depressed deep tendon reflexes, and showed no pain or temperature sensation caudal to Th-7 in spite of completely intact proprioception and vibration sensation. An echocardiogram showed no clots or vegetation on the prosthetic valve and no thrombus in the left atrium or left ventricle. The patient's paraplegia was permanent, at least through a follow-up period of 2 years. These findings suggest that the etiology was spinal cord ischemia due to blood supply in the area of the anterior spinal artery (ASA); however, magnetic resonance T2-weighted imaging demonstrated signal abnormalities throughout the gray matter and in the adjacent center white matter. Somatosensory-evoked potentials (SEP) measure neural transmission in the afferent spinal cord pathway, which is located in the lateral and posterior columns of the white matter; these showed a delay in latency between Th-6 and Th-7. The spinal cord is as vulnerable to transient ischemia as the brain. Spinal cord ischemia after cardiac arrest results from principal damage in the anterior horn of the gray matter, the so-called ASA syndrome; however, the pathways of SEP and pathogenesis of the spinal cord ischemia need further investigation.

Evoked Potentials, Somatosensory↗

PubMedDate not supplied

Emergence of oscillations in a model of weakly coupled two Bonhoeffer-van der Pol equations.

Bifurcations of periodic solutions in a model of weakly coupled two Bonhoeffer-van der Pol equations are studied. The model realizes a half-center model with reciprocal inhibition, a typical model used in the field of neural motor control to account for the generation of alternating rhythmic bursts observed in motoneurons and spinal neural networks. Several oscillatory solutions such as in-phase, anti-phase as well as out-of-phase solutions emerge from the model's equilibrium as one of the parameters of the model changes. Among the variety of bifurcations exhibited by the model, we analyze Hopf bifurcations, by which several periodic solutions emerge, and illustrate generation mechanisms of alternating oscillations in the model.

Models, Neurological↗

PubMedDate not supplied

Sharing Pacific-Rim experiences in disasters: summary and action plan.

INTRODUCTION: The discussions in this theme provided an opportunity to address the unique hazards facing the Pacific Rim. METHODS: Details of the methods used are provided in the preceding paper. The chairs moderated all presentations and produced a summary that was presented to an assembly of all of the delegates. Since the findings from the Theme 3 and Theme 7 groups were similar, the chairs of both groups presided over one workshop that resulted in the generation of a set of action plans that then were reported to the collective group of all delegates. RESULTS: The main points developed during the presentations and discussion included: (1) communication, (2) coordination, (3) advance planning and risk assessment, and (4) resources and knowledge. DISCUSSION: Action plans were summarized in the following ideas: (1) plan disaster responses including the different types, identification of hazards, focusing training based on experiences, and provision of public education; (2) improve coordination and control; (3) maintain communications, assuming infrastructure breakdown; (4) maximize mitigation through standardized evaluations, the creation of a legal framework, and recognition of advocacy and public participation; and (5) provide resources and knowledge through access to existing therapies, the media, and increasing and decentralizing hospital inventories. CONCLUSIONS: The problems in the Asia-Pacific rim are little different from those encountered elsewhere in the world. They should be addressed in common with the rest of the world.

Asia↗

PubMedDate not supplied

Interaction of sesame oil with soybean phosphatidylcholine and their formation of small dispersed particles.

Stable aqueous dispersions of sesame oil (SO) were obtained by co-sonication with soybean phosphatidylcholine (PC) in the SO mole fraction range of 0.1-0.8. In order to clarify the dispersal mechanism, the dispersed particles were characterized and the interaction of SO with PC was investigated using several physicochemical techniques. Dynamic light scattering measurements showed that the diameter of the dispersed particles was 40-60 nm. The trapped aqueous volume inside the particles was determined fluorometrically using the aqueous space marker, calcein. The trapped volume in the SO/PC particles decreased remarkably with the addition of SO into small unilamellar vesicles of PC. The decline in fraction of vesicular particles was also confirmed by fluorescence quenching of N-dansylhexadecylamine in the PC membrane by the addition of the quencher CuSO4. These results indicate that the excess SO separated from the PC bilayers is stabilized as emulsion particles by the PC surface monolayer. Monolayer-bilayer equilibrium of SO/PC mixtures was estimated by measurements of spreading and collapse pressures. The results showed that the coexistence of emulsion particles (surface monolayer of PC + core of SO) with vesicular particles (bilayer) was critically important for the formation of stably dispersed particles of the lipid mixture.

Fluorescence↗

PubMedDate not supplied

Altered cytoskeletal protein synthesis in rat cardiac isografts.

Adult rats underwent surgical placement of heterotopic cardiac isografts. From 14 to 60 days postoperatively, native heart and transplanted heart protein synthesis was determined. Right ventricle and left ventricle free walls from native and transplanted hearts were dissected, minced into cubes, and incubated in medium containing sulfur-35 methionine. Tissue was harvested, washed, and homogenized in buffer and fractionated centrifugally. Specific radioactivity of polypeptides from transplant isograft right and left ventricle fractions were 6.36 +/- 5.1 and 4.93 +/- 3.6 (mean +/- SD, x 10(-6) cpm/mg protein), respectively. In contrast, native isograft right and left ventricle specific radioactivity was 1.71 +/- 1.49 and 1.07 +/- 0.88 (mean +/- SD, x 10(-6) cpm/mg protein), respectively. Autoradiograms of two-dimensional electrophoretograms revealed increased radiodensity of resolved polypeptides from transplanted and native hearts, which comigrated with nonsarcomeric (beta, gamma) actins. Skeletin and tubulin were prominent on one-and two-dimensional autoradiograms from 14 to 60 days. Radiolabeling of alpha actin polypeptide maximized at 14 days and was found to decrease at 30 and 60 days in comparison with nonsarcomeric actin isoforms. Correlative myocardial microscopic sections showed no fiber hypertrophy, but fiber atrophy was found. Results suggest a relative increase in polypeptide synthesis in the heterotopic transplanted heart samples.

Abdomen↗

PubMedDate not supplied

Reoperation after initial correction of tetralogy of Fallot.

Ten of 357 patients (2.8%) who had total correction of tetralogy of Fallot in our institute between 1955 and 1983 required intracardiac reoperation. The indication for reoperation included residual lesions alone or in combination with other lesions. The reoperation consisted of a new patch closure of a residual ventricular septal defect in nine, reconstruction of a residual right ventricular outflow tract obstruction in five, repair of a left ventricle-right atrium communication in two, repair of tricuspid insufficiency in two and closure of an atrial septal defect in one. None of these ten patients had died at early or late follow-up periods (mean 5.3 years) or required further reoperation. A patient who has one or two of the following criteria, which are surgically correctable, and who would face deterioration in symptomatic status without surgical intervention is a candidate for reoperation: (1) Qp/Qs greater than 1.5, (2) Systolic pressure gradient between RV and PA greater than 50 mmHg, (3) Mean RA pressure greater than 20 mmHg, (4) CTR greater than 65%, (5) NYHA class III or IV.

Adolescent↗

PubMedDate not supplied

Successful modified Senning operation for the repair of Taussig-Bing malformation.

Surgical correction was carried out successfully in a severely cyanotic 3-year-old boy with Taussig-Bing malformation. The cardiac anomaly was associated with semilunar valves side by side, and at the same height, a bilateral conus without pulmonary-mitral continuity and subpulmonary ventricular septal defect, on which pulmonary valve overode. The surgical correction consisted of the closure of the VSD by a right atrial approach and modified Senning procedure under profound hypothermic cardiac arrest with surface cooling and limited cardiopulmonary bypass. The patient survived operation and was doing well 10 months after surgery. To our knowledge, no other identical case with Taussig-Bing malformation has been corrected successfully by this procedure nor has previously been reported.

Cardiopulmonary Bypass↗