A case of intrathoracic dumb-bell ganglioneuroma and a surgical approach using spinal evoked potentials (SEP)

A successfully treated case of a seven-year-old girl with a left intrathoracic Dumb-bell ganglioneuroma is reported. The tumor was 10 cm in diameter. Preoperative angiography revealed that the location of tumor was very close to the Adamkiewicz artery. In order to prevent the artery from damaging, spinal evoked potentials (SEP) was used during the surgery and was very useful for monitoring the spinal cord. Although SEP has often been employed in spine surgery, the literature on the use of it for posterior mediastinal tumor is scarce. It is considered that SEP is very useful for not damaging the feeding artery to the spinal cord, and for preventing the postoperative neurologic complications.     

Right thoracotomy to approach mitral or tricuspid valve in reoperation

Four patients underwent mitral valve re-replacement, and required tricuspid annuloplasty in two, through a right thoracotomy. There was no major postoperative morbidity and recovery was full and uneventful. The indications for selection of this approach were isolated mitral valve disease or combined tricuspid and mitral valve disease, severe adhesion between heart and sternum on CT scan, intact aortic valve and no severe reduction of respiratory function. We recommend right thoracotomy to approach atrioventricular valves in selected situations in patients for reoperations.     

Treatment of thoracic malignancy accompanied with cardiovascular disease

We treated 10 cases of thoracic malignancy accompanied with cardiovascular disease. Among thoracic malignancy, 7 cases were lung cancer and 3 were esophageal cancer. Accompanied cardiovascular diseases were ischemic heart disease (2 cases), valvular disease (3 cases), WPW syndrome (1 case), aortic aneurysm (4 cases). The mean age was 66, ranged from 51 to 79. The simultaneous occurrence of the two lesions were observed in 6 cases and thoracic malignancy was diagnosed after a varying interval of time following surgery of cardiovascular disease in 4 cases. In cases of thoracic malignancy accompanied with heart disease, the treatment of heart disease should precede the operation of malignant disease to reduce the risk of surgery. For the patient with esophageal cancer, posterior mediastinal esophagostomy should be applied who may have heart surgery in future. In cases of coexisting malignancy and aortic aneurysm, the priority of treatment should be determined considering the size of aneurysm. If the transverse diameter of aneurysm is larger than 7 cm, there is a high risk of rupture, so surgery for the aneurysm precedes operation of malignant diseases. It is desirable to avoid concomitant operation of malignancy and cardiovascular disease.     

Threshold currents of 1.2-1.55 μm P-substrate buried crescentlaser diodes

P-substrate buried crescent (PCB) laser diodes whose wavelength ranged from 1.2 to 1.55 μm have been fabricated. The threshold currents as low as 10 mA have been obtained in this wavelength range experimentally. The calculated threshold currents of 13, 13, and 14 mA at 1.2, 1.3, and 1.55 μm almost coincide with the measured values     

A case of recurrent esophageal cavernous hemangioma increasing rapidly after surgery

AIM: This study was designed to stress the importance of early diagnosis of fetomaternal hemorrhage (FMH) in attempt to prevent the subsequent adverse outcome on the fetus and the newborn. PATIENTS AND METHODS: Nine newborns were admitted because of neonatal anemia to our neonatal unit from October 1989 through September 1995. The diagnosis of FMH was made by the sigma diagnostic fetal hemoglobin that is the Kleihauer test in our hematologic laboratory. Other causes of neonatal anemia have been ruled out. RESULTS: Seven out of the nine cases have expressed early signs of fetal distress in term of abnormal fetal monitoring and/or thick meconium associated with decreased fetal movements. At birth, a wide clinical spectrum depending on the amount of the hemorrhage was seen, ranging from mild anemia with no symptoms (four cases), hypovolemic shock (one case), respiratory distress syndrome (two cases) and maladjustment to extra-uterine life (one case). There was one death at 48 hours after birth; one infant survived with severe encephalopathy. CONCLUSION: These results indicate that it is mandatory to carry out a Kleihauer test whenever a high suspicious index of FMH is faced or an unexplained neonatal anemia is found.     

Highly efficient 1.5 μm DFB-PPIBH laser diode with very narrowbeam

Highly efficient 1.5 μm distributed feedback p-substrate partially inverted buried heterostructure laser diodes have been developed using a metal organic chemical vapour deposition technique. An average efficiency of 0.26 mW/mA and maximum efficiency of 0.39 mW/mA were achieved. A full width at half-maximum perpendicular to the junction plane of 25° was obtained     

Degradation mechanism in 1.3 ?m InGaAsP/InP buried crescent laser diode at a high temperature

A leakage current flowing through a junction between a p-InP current blocking layer and an n-InP cladding layer is examined in connection with a degradation of a buried crescent laser diode at a high temperature. The degradation characteristics have been successfully explained by a theoretical model proposed in this study.     

Operon structure optimization by random self-assembly

Synthetic biology is an emerging research area that aims to investigate natural biological phenomena and reconstruct complex artificial biological systems. Recent development of genetic engineering such as multiple gene assembly method accelerates the synthetic biology study. Ordered gene assembly in Bacillus subtilis (OGAB method) is to assemble multiple genes in one step using an intrinsic B. subtilis plasmid transformation system and enables to reconstitute sets of relevant genes. The OGAB method assembles multiple DNA fragments with a fixed order and orientation and constructs an operon structure in a resultant plasmid. However, the optimal order and orientation to reconstitute a set of genes are generally not trivial and depends on several factors in host bacteria, where the “optimal” means the efficiency of biosynthesis induced by transferred genes in a metabolic pathway. We propose a method to apply self-assembly technique to optimization problem of operon structure. Self-assembly of multiple genes generates all possible orders of genes on operon structure. The number of generated orders on operon structure becomes the factorial of the number of multiple genes. All generated orders of multiple genes are then introduced into E. coli cells and most prominent colony for biosynthesis is extracted. We show some preliminary experiment to construct more efficient orders for five genes in the carotenoid biosynthetic pathway, and found a new order that is more efficient than previous studies for gene order.     

Concentration quenching of a red emitting electroluminescent dye tetraphenylporphyrin: A time-resolved photoluminescence study

This work deals with the steady-state and time-resolved photoluminescence study of a well-known red emitting electroluminescent dye, tetraphenylporphyrin (TPP), doped in poly(methylmethacrylate). From the time-resolved photoluminescence (PL) study, exponential decay of TPP emission was observed for these doped films in the studied concentrations region (10~mol/L). At lower doping concentrations below 10 mol/L, PL lifetimes of TPP were relatively constant (∼ 10 ns) and equal to that of TPP in dilute solution. A decrease in PL lifetime was observed at high doping concentration, down to 8 ns at a concentration of 10 mol/L. This observed decrease in PL lifetime of TPP with the increase of TPP concentration was due to the concentration quenching of TPP monomer emission by the TPP dimer/aggregate sites formed at such higher concentrations. The results of concentration quenching in TPP system were compared to that of tetraphenylchlorin system reported earlier.