[Recurrent intrathoracic dissemination of thymoma with myasthenia gravis: a case report]

A 48-year-old man was readmitted to our hospital with a chief complaint of left anterior chest mass. He had a past history of thymo-thymomectomy six years earlier. On chest CT examination, multiple tumor shadows were noted within the left thoracic cavity. All visible tumors were resected. His postoperative course was favorable, and no signs of recurrence have been recognized on CT to date (three years and six months postoperatively). However, in view of the possible recurrence of the present disease after a long period, strict observation of the course of the disease is necessary.

Cloning and sequencing of an alpha-glucosidase gene from Aspergillus niger and its expression in A. nidulans

We have cloned an extracellular alpha-glucosidase gene from Aspergillus niger with oligonucleotide probes synthesized on the basis of the determined peptide sequences. The nucleotide sequence revealed an open reading frame of 985 amino acids split with three introns, and the deduced amino acid sequence was nearly identical to that of the alpha-glucosidase previously determined. The cloned gene was introduced into Aspergillus nidulans, and its expression in the transformants was shown to be regulated by the carbon sources in the medium, suggesting that a common regulatory expression system is shared by these two species as is the case of other starch-degrading enzymes of Aspergillus species.

Blood cyst of the pulmonary valve in an adult: report of a case and review of the literature

We report a case of a blood cyst originating from the pulmonary valve cusp of a 43-year-old Japanese woman with pulmonary stenosis. Cineangiography revealed a pedunculated tumor on the arterial surface of the pulmonary valve. It was successfully removed by a transpulmonary artery approach. The cyst contained old blood and calcified thrombi, and its wall consisted of collagenous fibrous tissue. Immunohistochemically, a monolayer of flat cells lining the cyst was confirmed as endothelium using antibodies to von Willebrand factor and CD34, as well as UEA-I lectin. To the best of our knowledge, blood cysts of the pulmonary valve are rare and only 10 such cases have been reported, including six pediatric cases. This case is the oldest and fifth adult patient with a blood cyst found on the pulmonary valve. A possible histogenesis is discussed.

Phospholamban deficiency alters inactivation kinetics of L-type Ca2+ channels in mouse ventricular myocytes

Entry of Ca2+ through voltage-dependent L-type Ca2+ channels is critical for contraction in cardiac cells. In recent studies, cells from phospholamban (PLB) knockout (PLB-KO) mouse hearts showed significantly increased basal contractility with enhanced sarcoplasmic reticulum (SR) Ca2+ uptake. To test whether these effects of PLB ablation were associated with alterations of L-type Ca2+ channel function, we compared the properties of Ca2+ channel currents (I(Ca)) in ventricular myocytes isolated from wild-type (WT) and PLB-KO mouse hearts. L-type Ca2+ channels from mouse myocytes exhibited voltage-dependent gating and sensitivity to dihydropyridine drugs, similar to other mammalian species, and these properties were not altered by PLB ablation. I(Ca) from both WT and PLB-KO cells revealed two (fast and slow) components of inactivation kinetics. However, the proportion of the faster component was significantly larger in PLB-KO cells. Ryanodine (10 microM) reduced the rate of inactivation of I(Ca) for both WT and PLB-KO cells, but the reduction was more prominent in PLB-KO cells compared with WT cells. In contrast, the inactivation in a Ba2+ solution could be fitted by a single exponential similar to the slower component in Ca2+, and this was not altered in PLB-KO cells. The increase in the fast Ca2+-dependent inactivation component in PLB-KO cells supports the hypothesis that Ca2+ released from the SR regulates Ca2+ channel inactivation by affecting the levels of Ca2+ near the channel and suggests that this may be an important compensatory mechanism in the hyperdynamic PLB-KO heart.

Cloning, sequencing, and expression of a thermostable cellulase gene of Humicola grisea

The egl2 gene coding a thermostable endoglucanase (EGL2) was cloned from Humicola grisea. The DNA sequence of egl2 predicted two putative introns in the coding region. The deduced amino acid sequence of EGL2 was 388 amino acids in length and showed 99.5% identity with the H. insolens CMC 3. In addition to TATA box and CAAT motifs, putative CREA binding sites were observed in the 5' upstream region of the egl2 gene. The egl2 gene was expressed in Aspergillus oryzae, and EGL2 was purified. EGL2 produced by A. oryzae showed a high activity toward carboxymethyl cellulose. The optimal temperature of EGL2 was 75 degrees C, and EGL2 had more than 80% residual activity after heating up to 75 degrees C for 10 min. This is the first report of enzymatic properties of the EGL2-type thermostable cellulase homologs from Humicola.

[A clinical study of skin flora in patients with MRSA colonization after introduction of preventive measures of hospital infection in a geriatric ward]

In early 1980's methicillin-resistant Staphylococcus aureus (MRSA) was reported as a major pathogenic organism of geriatric hospital infection in Japan. At the same time in the geriatric hospital MRSA infection was prevalent. To decrease nosocomial infections some active preventive measures against hospital infection were taken since Oct. 1991. After introduction of preventive measures of hospital infection in the geriatric ward (190 beds) nosocomial bacteremia and pneumonia were markedly decreased in comparison of episode number before introduction of prevention. However several patients with MRSA colonization were observed every month. The aim of this clinical study was to clear how frequent MRSA was isolated from skin. Consequently 3 strains (3.4%) of MRSA were observed in 86 cultured skin. In conclusion we considered frequency of MRSA colonization frequency of MRSA colonization on skin was not so high but rather very low under the preventive measures.

[A case report of malignant schwannoma of the chest wall]

We described a very rare case of malignant schwannoma of the chest wall, which was surgically resected. The patient, a 40-year-old woman, came to our hospital because of an abnormal shadow in the right chest wall of an X-ray film without any symptoms. Computed tomography revealed a solid tumor attached to the posteroinferior aspect of the intrathoracic chest wall. The tumor was a 2.5 x 2.1 cm, mass originating from the seventh intercostal nerve without pulmonary adhesion, and the patient underwent en bloc resection of the tumor. The pathological diagnosis was malignant schwannoma. The postoperative course was uneventful, and the patient, eight years after the operation is now doing well without local recurrence or distant metastasis. We reviewed seven cases of this type of tumor reported in the Japanese literature.

Establishment and characterization of an anti-idiotypic CD4+ CD8- T cell line to murine anti-alpha(1 --> 3) dextran antibody

It is known that anti-alpha(1 --> 3) dextran antibodies of BALB/c mice are ordinarily of distinctive idiotypes (Id), one of which is the individual idiotype (IdI) that is represented by J558 or M104E to myeloma protein. In the present study, we established T cell line of Th1 type which recognized the Id of anti-alpha(1 --> 3) dextran antibody, and investigated its specificity and functions. The T cell line, named J-2R, had a phenotype of CD3+ CD4+ CD8- and expressed alphabeta-T cell receptors (TcR). J-2R proliferated in response to J558 in an I-Ed-restricted manner but did not respond to M104E which had substitution at amino acids 100 and 101. We confirmed that J-2R recognized J558 IdI, using synthetic peptides corresponding to two serial amino acid residues, Arg100 and Tyr101, spanning the J558 IdI in the third hypervariable region (hv3) of the heavy chain. alpha(1 --> 3) dextran-binding B cells which were isolated from dextran-immunized mice activated J-2R, but B cells from nonimmune mice did not. J-2R produced IL-2, IFN-gamma and IL-6, but did not produce IL-4, IL-5, or IL-10. Furthermore, J-2R inhibited the growth of J558 myeloma cells inoculated to the syngeneic mice in vivo. These findings suggest that Id-specific CD4+ T cells, J-2R, are involved in Id network and may play a role in vivo. J-2R is useful for analysis of the role of the Id-specific helper T cells in immune network because J558 IdI is frequently present on anti-alpha(1 --> 3) dextran antibodies.

Analysis of Cre1 binding sites in the Trichoderma reesei cbh1 upstream region

A 1.5-kb XbaI-SacII fragment containing the upstream region of the Trichoderma reesei cellobiohydrolase I gene (cbh1) has been sequenced. The 1.5-kb fragment contains eight 6-bp sites having an identical or similar sequence to the consensus sequence for binding a catabolite repressor, Aspergillus nidulans CreA. Results of binding assays with the maltose-binding protein::Cre1(10-131) fusion protein (Cre1 is a catabolite repressor of T. reesei) and the cbh1 upstream region revealed that a 504-bp XbaI-NspV fragment (nucleotide position -1496 to -993) bearing three 6-bp sites, A1, A2, and A3, and a 356-bp NspV-MunI fragment (nucleotide position -994 to -639) bearing three 6-bp sites, B1, B2, and B3, were shifted in the electrophoretic mobility shift assay. DNase I footprinting experiments showed that the 6-bp sites A2, B1, B2, and B3 were protected from DNase I digestion.

[Traumatic injuries of the thoracic aorta--report of five cases]

Five cases of traumatic aneurysm of the thoracic aorta associated with blunt chest trauma are described. Although we lost one case, four cases were successfully treated. Case 1, This was a 22-year-old female who underwent surgery for graft replacement of the descending thoracic aorta under extracorporeal circulation two days after injury. Case 2, This was a 17-year-old male who underwent surgery for graft replacement of the descending thoracic aorta under extracorporeal circulation 24 hours after injury. Case 3, This was a 56-year-old female who underwent surgery for graft replacement of the descending thoracic aorta under extracorporeal circulation 24 hours after injury. Case 4, This was a 69-year-old male who underwent surgery for graft replacement with three branches for an aortic arch aneurysm under extracorporeal circulation one month after injury. Despite an emergency operation, we lost case 5 (a 21-year-old male) because of a complete discontinuity of the aortic isthmus. The postoperative course of the other four cases was uneventful. Vessel injury may be more widespread than preoperative radiographic findings demonstrates. Blunt chest trauma is usually accompanied by multisystem injury. Therefore, it is imperative to determine the first priority of treatment based on further preoperative examination in cases having associated injuries.

Cloning, sequencing, and expression of the cellulase genes of Humicola grisea var. thermoidea

We have cloned an endoglucanase (EGI) gene and a cellobiohydrolase (CBHI) gene of Humicola grisea var. thermoidea using a portion of the Trichoderma reesei endoglucanase I gene as a probe, and determined their nucleotide sequences. The deduced amino acid sequence of EGI was 435 amino acids in length and the coding region was interrupted by an intron. The EGI lacks a hinge region and a cellulose-binding domain. The deduced amino acid sequence of CBHI was identical to the H. grisea CBHI previously reported, with the exception of three amino acids. The H. grisea EGI and CBHI show 39.8% and 37.7% identity with T. reesei EGI, respectively. In addition to TATA box and CAAT motifs, putative CREA binding sites were observed in the 5' upstream regions of both genes. The cloned cellulase genes were expressed in Aspergillus oryzae and the gene products were purified. The optimal temperatures of CBHI and EGI were 60 degrees C and 55-60 degrees C, respectively. The optimal pHs of these enzymes were 5.0. CBHI and EGI had distinct substrate specificities: CBHI showed high activity toward Avicel, whereas EGI showed high activity toward carboxymethyl cellulose (CMC).

Isolation and characterization of the nuclease O gene (nucO) from Aspergillus oryzae

Nuclease O in the mycelia of Aspergillus oryzae has been purified 55-fold by successive steps of chromatography from the filtrate of the autolyzate. The molecular mass of nuclease O was 32 kDa, as estimated by SDS polyacrylamide-gel electrophoresis. The nuclease O gene (nucO) encoding this enzyme was cloned and sequenced. The open reading frame is interrupted by four introns with conserved splice sites and contains 328 amino-acid residues of the mature enzyme. A. nidulans transformants obtained by introduction of the cloned nucO gene produced 2.5-times as much nuclease O as the wild-type strain, showing that the cloned DNA fragment encodes nuclease O.

[Result of surgery for aneurysms of distal aortic arch and proximal descending aorta]

We examined the surgical result for non-dissecting aneurysm of distal aortic arch and proximal descending aorta, for which aneurysm, proximal aortic clamp cannot be set at descending aorta because of the proximal progression of aneurysm. In 25 cases out of all 46 cases for 18 years, before 1990, aortic arch was clamped for proximal aortic control with the aid of temporary bypass, femoral artery-vein bypass or left heart bypass (clamp group). In 10 cases proximal aortic clamp was set between innominate and left common carotid artery and in 15 cases between left common carotid artery and left subclavian artery. In the former, temporary or permanent bypass was made to left common carotid artery. After 1990, in 21 cases, aortic arch was not clamped with the aid of separate cerebral perfusion (no clamp group). In the comparison of surgical result between two groups, no clamp group showed less postoperative complication rate in brain damage (28% vs 14%) and bleeding (16% vs 5%) and showed better operative mortality (20% vs 14%) and better hospital mortality (32% vs 19%). Now, in the surgery for non-dissecting aneurysm of diatal aortic arch and proximal descending aorta, it is preferable not to clamp aortic arc, employing separate cerebral perfusion.

[Long-term results of emergency coronary artery bypass grafting]

During a 20-year period, 364 patients underwent coronary artery bypass grafting (CABG) for the treatment of ischemic heart disease. Among these patients, 28 underwent emergency surgery. The reasons for performing emergency CABG were unstable angina in 15 patients, impending myocardial infarction in 12 patients, and congestive heart failure in 1 patient. Eleven patients died postoperatively. Eight variables were examined by univariate analysis for their influence on the occurrence of a hospital death. IABP and acute coronary occlusion were found to be predictors of hospital death and previous myocardial infarction was a predictor of hospital survival. Seventeen patients were followed up for 12 years. There was no cardiac death and actuarial survival at 12 years was 63%. The 14 survivors are now in NYHA functional class I or II. Although the operative mortality rate is high after emergency CABG, the patient's prognosis is good.

Long-term results of emergency coronary artery bypass grafting

During a 20-year period, 364 patients underwent coronary artery bypass grafting (CABG) for the treatment of ischemic heart disease. Among these patients, 28 underwent emergency surgery. The reasons for performing emergency CABG were unstable angina in 15 patients, impending myocardial infarction in 12 patients and congestive heart failure in 1 patient. Eleven patients died postoperatively. Eight variables were examined by univariate analysis for their influence on the occurrence of a hospital death. Lack of a history of myocardial infarction, intraaortic balloon pumping (IABP) and acute coronary occlusion were all found to be predictors of hospital death. Seventeen patients were followed up for 12 years. There was no cardiac death and actuarial survival at 12 years was 63%. The 14 survivors are now in NYHA functional class I or II. Although the operative mortality rate is high after emergency CABG, a fair prognosis can be expected if the patients survive surgery.

[Underlying cardiac disease in infective endocarditis]

Underlying cardiac lesions in 39 adult cases with infective endocarditis were studied. 18 cases (46%) of the patients had no evidence of preexisting cardiac disease and infection frequently involved aortic valve. The patients without preexisting cardiac disease and 4 patients with an intracardiac substitute including pacemaker lead and aortic valve prosthesis required a surgery during an active infective endocarditis. All cases of active infective endocarditis accompanied with rheumatic valvular disease underwent surgery after a suppression of active inflammation by medical treatment.

[A case of tricuspid and mitral valve replacement for incomplete endocardial cushion defect]

A 56-year-old female who was diagnosed incomplete endocardial cushion defect, underwent closure of ostium primum defect and repair of mitral cleft 2 years ago. Mitral and tricuspid ring annuloplasty was done 9 months after the first operation because of an increment of mitral and tricuspid valve regurgitation. The Third operation, mitral valve replacement by mechanical valve and tricuspid valve replacement by bioprosthetic valve, was performed because of the gradually increased mitral stenosis and tricuspid regurgitation. Post-operative course was uneventful. Resected anterior cusp of mitral and tricuspid valve revealed hypertrophy and shortness macroscopically, and revealed fibrosis and calcification histopathologically. It was considered that remarkable regurgitation was due to secondary change of both valves. We concluded that valve replacement should be performed for case of secondary change of atrioventricular valve in adult patient.

[A case of swallowed fish bone-induced esophageal perforation and mediastinitis treated with pedicled omental graft]

We experienced a case of 47-year-old man who suffered swallowed fish bone-induced esophageal perforation with purulent mediastinitis and underwent direct suture closure of the perforation and reinforcement with a pedicled parietal pleura four days after the onset. Postoperative esophageal suture insufficiency was occured and reoperation was performed two months after the first operation. The esophageal fistula was plugged with a pedicled omental graft successfully. The postoperative course of the patient was uneventful and he discharged 45 days after the second operation. A reinforcement by pedicled omental graft for esophageal rupture accompanied with mediastinitis was considered to be a useful procedure.

Influence of downscatter in simultaneously acquired thallium-201/technetium-99m-PYP SPECT

Simultaneously acquired dual-isotope imaging is a unique and useful approach in SPECT. Photon spillover, however, is a potential limitation of this technique.

METHODS

To investigate the degree of 99mTc downscatter into the 201Tl window in patients, simultaneously acquired dual-isotope 201Tl/99mTc-pyrophosphate imaging was performed in 17 patients with acute myocardial infarction (MI). Thallium-201 SPECT imaging was performed first, with a 201Tl photopeak window after the 201Tl injection (early 201Tl images), followed by 99mTc injection and SPECT acquisition using dual-isotope windows (dual 201Tl images). Twenty-four hours after the 99mTc injection, a third set of 201Tl images was obtained (24-hr 201Tl images). Thallium defect size (extent score) and defect severity (severity score) were calculated from these three sets of 201Tl images to quantify the MI.

RESULTS

Technetium-99m accumulation of varying intensity was recognized in all patients. Extent scores and severity scores were identical in early 201Tl images and 24-hr 201Tl images. Both scores, however, in the dual 201Tl images were decreased by 36% and 53%, respectively.

CONCLUSION

There in a considerable 99mTc downscatter into the 201Tl window, which prevents precise quantification of MI in simultaneously acquired dual-isotope 201Tl/99mTc-pyrophosphate imaging.

Cloning, sequencing and transcriptional regulation of the draT and draG genes of Azospirillum lipoferum FS

From Azospirillum lipoferum (Al) FS, a nitrogen-fixing bacterium isolated from the rhizosphere of rice, we cloned and sequenced draT, encoding dinitrogenase reductase ADP-ribosyltransferase, and draG, encoding dinitrogenase reductase-activating glycohydrolase. The nucleotide sequences of draTG showed extensive similarity to the same genes from Azospirillum brasilense, Rhodospirillum rubrum and Rhodobacter capsulatus, and they are assumed to be co-transcribed as a single operon. When this draTG operon was introduced into Klebsiella oxytoca, this organism acquired the ability to respond to extracellular NH(+4) ions with reversible inhibition of nitrogenase activity, similar to that seen in Al FS. We constructed a plasmid containing a draT::lacZ gene fusion and found that beta-galactosidase activity was detected under microaerobic conditions, regardless of NH(+4) concentration, but not under aerobic conditions. This indicates that the transcription of draTG responds to the level of oxygen, but not to that of NH(+4) ions.

Central nuclei and spinal pathways in feedback inhibitory spinal cord potentials in ketamine-anaesthetized rats

It has been suggested that heterosegmentally activated slow positive potentials (HSP), recorded from the spinal cord of rat and humans, are feedback inhibitory potentials. The present study was carried out to define ascending and descending spinal tracts and the sites of central nuclei involved in the production of these HSP, and the effects of ketamine on these central nuclei. The spinal cords in ketamine-anaesthetized rats were transected to determine the ascending and descending tracts involved in the production of hindpaw (HP) and forepaw (FP) HSP, respectively. Lesions of the brain at various levels were performed stereotactically during ketamine anaesthesia. Dorsal one-third resection of the cord at the T8-9 level did not affect HSP significantly, while contralateral lesion of the dorsal two-thirds of the cord decreased FP-HSP but not HP-HSP during ketamine. Bilateral transection of the ventral one-third of the cord abolished both HSP. Ablation of the cerebral cortex, cerebellum, thalamus, midbrain and pons did not affect HSP significantly. However, transection of the middle medulla decreased, while transection of the most caudal part of the medulla completely abolished both HSP. Ketamine decreased HSP even in the medulla-spinal cord preparation and the segmental slow positive wave in spinalized animals. In ketamine-anaesthetized rats, ascending and descending spinal tracts involved in the production of HP-HSP and FP-HSP are located bilaterally in the ventrolateral quadrant and in the contralateral lateral funiculus and ventrolateral quadrant, respectively. Principal central nuclei feeding back HSP might be situated diffusely in the medulla down to the caudal part. Ketamine is suggested to suppress these inhibitory feedback potentials predominantly at, and partly even below, the level of the medulla.

Modulation of pump function by mutations in the first transmembrane region of Na(+)-K(+)-ATPase alpha 1-subunit

The Cys in the first transmembrane region of the Na(+)-K(+)-adenosinetriphosphatase (ATPase) alpha 1-subunit has been shown to be a critical determinant of cardiac glycoside binding. To study the role of this Cys on ion transport activity, we measured pump currents in HeLa cells expressing wild-type or mutant alpha 1-subunit cDNAs. The endogenous ouabainsensitive Na(+)-K(+)-ATPase was selectively inhibited by growing the cells in 0.1 microM ouabain. A Cys-to-Tyr substituted mutant exhibited decreased sensitivity to digitoxin but not digoxin compared with wild type. The decreased affinity for digitoxin was due to a faster dissociation rate. In contrast, the Cys-to-Ala substitution did not significantly alter the sensitivity to digitoxin or digoxin. Both wild-type and mutant cells displayed marked external K(+)-dependent pump currents; however, the affinity for K+ was reduced by the mutations. The decrease in K+ affinity was due to a slower association rate. The results show that the Cys that interacts with cardiac glycosides also participates in the sensitivity of the pump to external K+.