Application of ultra-high voltage electron microscope tomography to 3D imaging of microtubules in neurites of cultured PC12 cells

Electron tomography methods using the conventional transmission electron microscope have been widely used to investigate the three-dimensional distribution patterns of various cellular structures including microtubules in neurites. Because the penetrating power of electrons depends on the section thickness and accelerating voltage, conventional TEM, having acceleration voltages up to 200 kV, is limited to sample thicknesses of 0.2 µm or less. In this paper, we show that the ultra-high voltage electron microscope (UHVEM), employing acceleration voltages of higher than 1000 kV (1 MV), allowed distinct reconstruction of the three-dimensional array of microtubules in a 0.7-µm-thick neurite section. The detailed structure of microtubules was more clearly reconstructed from a 0.7-µm-thick section at an accelerating voltage of 1 MV compared with a 1.0 µm section at 2 MV. Furthermore, the entire distribution of each microtubule in a neurite could be reconstructed from serial-section UHVEM tomography. Application of optimised UHVEM tomography will provide new insights, bridging the gap between the structure and function of widely-distributed cellular organelles such as microtubules for neurite outgrowth. LAY DESCRIPTION: An optimal 3D visualisation of microtubule cytoskeleton using ultra-high voltage electron microscopy tomography The ultra-high voltage electron microscope (UHVEM) is able to visualise a micrometre-thick specimen at nanoscale spatial resolution because of the high-energy electron beam penetrating such a specimen. In this study, we determined the optimal conditions necessary for microtubule cytoskeleton imaging within 0.7-µm-thick section using a combination with UHVEM and electron tomography method. Our approach provides excellent 3D information about the complex arrangement of the individual microtubule filaments that make up the microtubule network.

The effect of electroconvulsive seizure on survival, neuronal differentiation, and expression of the maturation marker in the adult mouse hippocampus

Electroconvulsive seizure (ECS), a model of electroconvulsive therapy in rodents, strongly increases neurogenesis in the adult hippocampus. Neurogenesis is a multi-step process that spans proliferation, survival, neuronal differentiation, and functional maturation. Our previous study demonstrated that ECS stimulates the proliferation of neural stem-like cells. However, the contribution of ECS to survival, neuronal differentiation, and maturation in newborn cells remains unknown. To evaluate the effect of ECS on these processes, we labeled newborn cells with bromodeoxyuridine (BrdU) before ECS treatment to determine the cell age and examined the survival rate and expression of cellular markers in the BrdU-labeled cells. Our results revealed that exposure to ECS (11 repetitions) during the differentiation phase significantly increased survival and promoted neuronal differentiation of newborn cells in the dentate gyrus. Four of ECS repetitions during the early differentiation phase were sufficient to promote dendritic outgrowth in immature neurons and enhance the expression of the immature neuronal marker, calretinin, in newborn cells. In contrast, exposure to ECS (11 repetitions) during the late maturation phase significantly suppressed the expression of the mature neuronal marker, calbindin, in newborn neurons. These results demonstrate that ECS during the differentiation phase promoted survival and neuronal differentiation and, in contrast, suppressed mature marker expression during the late maturation phase, suggesting that ECS has multiple effects on the different stages of adult neurogenesis.

Short-chain fatty acids induce tissue plasminogen activator in airway epithelial cells via GPR41&43

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous chronic inflammatory disease generally divided based on the presence or absence of nasal polyps (NPs). One of the features of NPs is excessive fibrin deposition, which is associated with down-regulation of tissue plasminogen activator (t-PA) in NPs. As t-PA is expressed in epithelial cells, and epithelium is readily accessible to topical therapies, identifying compounds that can mediate the induction of t-PA would be a potential new strategy for the treatment of NPs.

OBJECTIVE

The objective of this study was to determine whether short-chain fatty acids (SCFAs) can induce t-PA in airway epithelial cells via their known receptors GPR41 and GPR43.

METHODS

We performed immunohistochemistry (IHC) to determine whether receptors for SCFAs, known as G protein-coupled receptor 41/free fatty acid receptor 3 (GPR41/FFAR3) and GPR43/FFAR2, are expressed in nasal tissue. Primary normal human bronchial epithelial (NHBE) cells were stimulated with different concentrations of SCFAs to test induction of t-PA, which was analysed by expression of mRNA and protein. Mediation of responses by SCFA receptors was evaluated by specific receptor gene silencing with siRNA.

RESULTS

Immunohistochemistry study revealed that airway epithelial cells expressed GPR41 and GPR43. Acetic acid, propionic acid, butyric acid and valeric acid significantly induced t-PA expression from two- to tenfolds. The strongest inducer of t-PA from NHBE cells was propionic acid; cells stimulated with propionic acid released t-PA into the supernatant in its active form. Gene silencing of GPR41 and GPR43 revealed that induction of t-PA by SCFAs was dependent upon both GPR41 and GPR43.

CONCLUSIONS AND CLINICAL RELEVANCE

Short-chain fatty acids were shown to induce airway epithelial cell expression of t-PA via GPR41 and GPR43. Topical delivery of potent compounds that activate these receptors may have value by reducing fibrin deposition and shrinking nasal polyp growth.

Prolonged Inflation Technique Using a Scoring Balloon for Severe Calcified Lesion

Percutaneous coronary intervention for the treatment of a severe calcified lesion is still one of the most technically challenging areas of interventional cardiology. Calcified lesions are a cause of stent underexpansion, which significantly increases the subsequent risks of in-stent restenosis and thrombosis, even when drug-eluting stents are used. In this report, we describe the usefulness of prolonged inflations using a scoring balloon catheter (Scoreflex) for severe calcified lesions. Prolonged inflation using a scoring balloon enables an adequate dilation for treatment of a severe calcified plaque that was unresponsive to conventional technique with or without rotational atherectomy.

A left atrial appendage thrombus that developed during prophylactic low-dose dabigatran treatment resolved after switching to apixaban

We describe a case of atrial fibrillation in which an intracardiac thrombus that could not be prevented with “low‐dose” dabigatran treatment was resolved by switching to apixaban treatment. Thrombolysis using direct oral anticoagulants (DOACs) could be a therapeutic option for patients with intracardiac thrombi, although the efficacies of different DOACs seem to differ and need further examination.

Rapid and stable changes in maturation-related phenotypes of the adult hippocampal neurons by electroconvulsive treatment

Electroconvulsive therapy (ECT) is a highly effective and fast-acting treatment for depression. Despite a long history of clinical use, its mechanism of action remains poorly understood. Recently, a novel cellular mechanism of antidepressant action has been proposed: the phenotype of mature brain neurons is transformed to immature-like one by antidepressant drug treatments. We show here that electroconvulsive stimulation (ECS), an animal model of ECT, causes profound changes in maturation-related phenotypes of neurons in the hippocampal dentate gyrus of adult mice. Single ECS immediately reduced expression of mature neuronal markers in almost entire population of dentate granule cells. After ECS treatments, granule cells showed some of physiological properties characteristic of immature granule cells such as higher somatic intrinsic excitability and smaller frequency facilitation at the detate-to-CA3 synapse. The rapid downregulation of maturation markers was suppressed by antagonizing glutamate NMDA receptors, but not by perturbing the serotonergic system. While single ECS caused short-lasting effects, repeated ECS induced stable changes in the maturation-related phenotypes lasting more than 2 weeks along with enhancement of synaptic excitation of granule cells. Augmentation of synaptic inhibition or blockade of NMDA receptors after repeated ECS facilitated regaining the initial mature phenotype, suggesting a role for endogenous neuronal excitation in maintaining the altered maturation-related phenotype probably via NMDA receptor activation. These results suggest that brief neuronal activation by ECS induces "dematuration" of the mature granule cells and that enhanced endogenous excitability is likely to support maintenance of such a demature state. The global increase in neuronal excitability accompanying this process may be relevant to the high efficacy of ECT.

Rapid and lasting enhancement of dopaminergic modulation at the hippocampal mossy fiber synapse by electroconvulsive treatment

Electroconvulsive therapy (ECT) is an established effective treatment for medication-resistant depression with the rapid onset of action. However, its cellular mechanism of action has not been revealed. We have previously shown that chronic antidepressant drug treatments enhance dopamine D₁-like receptor-dependent synaptic potentiation at the hippocampal mossy fiber (MF)-CA3 excitatory synapse. In this study we show that ECT-like treatments in mice also have marked effects on the dopaminergic synaptic modulation. Repeated electroconvulsive stimulation (ECS), an animal model of ECT, strongly enhanced the dopamine-induced synaptic potentiation at the MF synapse in hippocampal slices. Significant enhancement was detectable after the second ECS, and further repetition of ECS up to 11 times monotonously increased the magnitude of enhancement. After repeated ECS, the dopamine-induced synaptic potentiation remained enhanced for more than 4 wk. These synaptic effects of ECS were accompanied by increased expression of the dopamine D₁ receptor gene. Our results demonstrate that robust neuronal activation by ECS induces rapid and long-lasting enhancement of dopamine-induced synaptic potentiation at the MF synapse, likely via increased expression of the D₁ receptor, at least in part. This rapid enhancement of dopamine-induced potentiation at the excitatory synapse may be relevant to the fast-acting antidepressant effect of ECT.

NEW & NOTEWORTHY

We show that electroconvulsive therapy (ECT)-like stimulation greatly enhances synaptic potentiation induced by dopamine at the excitatory synapse formed by the hippocampal mossy fiber in mice. The effect of ECT-like stimulation on the dopaminergic modulation was rapidly induced, maintained for more than 4 wk after repeated treatments, and most likely mediated by increased expression of the dopamine D1 receptor. These effects may be relevant to fast-acting strong antidepressant action of ECT.

Novel scoring system and algorithm for classifying chronic rhinosinusitis: the JESREC Study

Background

Chronic rhinosinusitis (CRS) can be classified into CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). CRSwNP displays more intense eosinophilic infiltration and the presence of Th2 cytokines. Mucosal eosinophilia is associated with more severe symptoms and often requires multiple surgeries because of recurrence; however, even in eosinophilic CRS (ECRS), clinical course is variable. In this study, we wanted to set objective clinical criteria for the diagnosis of refractory CRS.

Methods

This was a retrospective study conducted by 15 institutions participating in the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis (JESREC). We evaluated patients with CRS treated with endoscopic sinus surgery (ESS), and risk of recurrence was estimated using Cox proportional hazard models. Multiple logistic regression models and receiver operating characteristics curves were constructed to create the diagnostic criterion for ECRS.

Results

We analyzed 1716 patients treated with ESS. To diagnose ECRS, the JESREC scoring system assessed unilateral or bilateral disease, the presence of nasal polyps, blood eosinophilia, and dominant shadow of ethmoid sinuses in computed tomography (CT) scans. The cutoff value of the score was 11 points (sensitivity: 83%, specificity: 66%). Blood eosinophilia (>5%), ethmoid sinus disease detected by CT scan, bronchial asthma, aspirin, and nonsteroidal anti‐inflammatory drugs intolerance were associated significantly with recurrence.

Conclusion

We subdivided CRSwNP in non‐ECRS, mild, moderate, and severe ECRS according to our algorithm. This classification was significantly correlated with prognosis. It is notable that this algorithm may give useful information to clinicians in the refractoriness of CRS before ESS or biopsy.

Role of the 5-HT4 receptor in chronic fluoxetine treatment-induced neurogenic activity and granule cell dematuration in the dentate gyrus

Background

Chronic treatment with selective serotonin (5-HT) reuptake inhibitors (SSRIs) facilitates adult neurogenesis and reverses the state of maturation in mature granule cells (GCs) in the dentate gyrus (DG) of the hippocampus. Recent studies have suggested that the 5-HT₄ receptor is involved in both effects. However, it is largely unknown how the 5-HT₄ receptor mediates neurogenic effects in the DG and, how the neurogenic and dematuration effects of SSRIs interact with each other.

Results

We addressed these issues using 5-HT₄ receptor knockout (5-HT4R KO) mice. Expression of the 5-HT₄ receptor was detected in mature GCs but not in neuronal progenitors of the DG. We found that chronic treatment with the SSRI fluoxetine significantly increased cell proliferation and the number of doublecortin-positive cells in the DG of wild-type mice, but not in 5-HT4R KO mice. We then examined the correlation between the increased neurogenesis and the dematuration of GCs. As reported previously, reduced expression of calbindin in the DG, as an index of dematuration, by chronic fluoxetine treatment was observed in wild-type mice but not in 5-HT4R KO mice. The proliferative effect of fluoxetine was inversely correlated with the expression level of calbindin in the DG. The expression of neurogenic factors in the DG, such as brain derived neurotrophic factor (Bdnf), was also associated with the progression of dematuration. These results indicate that the neurogenic effects of fluoxetine in the DG are closely associated with the progression of dematuration of GCs. In contrast, the DG in which neurogenesis was impaired by irradiation still showed significant reduction of calbindin expression by chronic fluoxetine treatment, suggesting that dematuration of GCs by fluoxetine does not require adult neurogenesis in the DG.

Conclusions

We demonstrated that the 5-HT₄ receptor plays an important role in fluoxetine-induced adult neurogenesis in the DG in addition to GC dematuration, and that these phenomena are closely associated. Our results suggest that 5-HT₄ receptor-mediated phenotypic changes, including dematuration in mature GCs, underlie the neurogenic effect of SSRIs in the DG, providing new insight into the cellular mechanisms of the neurogenic actions of SSRIs in the hippocampus.

Eosinophils control the resolution of inflammation and draining lymph node hypertrophy through the proresolving mediators and CXCL13 pathway in mice

Resolution of inflammation is critical to restoration of tissue function after an inflammatory response. We previously demonstrated that 12/15-lipoxygenase (12/15-LOX)-expressing eosinophils contribute to this process in murine zymosan-induced peritonitis. In this study, eosinophils promoted resolution by regulating expression of macrophage CXCL13. Microarray analysis revealed that eosinophils significantly increased (∼3-fold) the expression of macrophage CXCL13 by a 12/15-LOX-dependent mechanism. CXCL13 depletion caused a resolution defect, with the reduced appearance of phagocytes carrying engulfed zymosan in the draining lymph nodes. Inflamed lymph node hypertrophy, a critical feature of the resolution process, was reduced by ∼60% in eosinophil-deficient mice, and adoptive transfer of eosinophils or administration of CXCL13 corrected this defect. Administration of the 12/15-LOX-derived mediator lipoxin A4 (LXA4) increased the expression of CXCL13 and restored the defect of lymph node hypertrophy in eosinophil-deficient mice. These results demonstrate that eosinophils control the resolution of inflammation and draining lymph node hypertrophy through proresolving lipid mediators and the CXCL13 pathway in mice.

Electroconvulsive seizures activate anorexigenic signals in the ventromedial nuclei of the hypothalamus

The ventromedial nucleus of the hypothalamus (VMH) plays an important role in feeding and energy homeostasis. Electroconvulsive seizure (ECS) therapy is highly effective in the treatment of several psychiatric diseases, including depression, but may also have beneficial effects in other neurological diseases. Although it has been reported that the neurons of the VMH are strongly activated by ECS stimulation, the specific effects of ECS in this hypothalamic subnucleus remain unknown. To address this issue, we investigated the changes in gene expression in microdissected-VMH samples in response to ECS in mice, and examined the behavioral effects of ECS on feeding behavior. ECS significantly induced the expression of immediate-early genes such as Fos, Fosb, and Jun, as well as Bdnf, Adcyap1, Hrh1, and Crhr2 in the VMH. Given that signals of these gene products are suggested to have anorexigenic roles in the VMH, we also examined the effect of ECS on food intake and body weight. Repeated ECS had a suppressive effect on food intake and body weight gain under both regular and high-fat diet conditions. Furthermore, gold-thioglucose-induced hypothalamic lesions, including the VMH and the arcuate nucleus, abolished the anorexigenic effects of ECS, indicating the requirement for the activation of the hypothalamus. Our data show an effect of ECS on increased expression of anorexigenic factors in the VMH, and suggest a role in the regulation of energy homeostasis by ECS.

[Extended thymectomy and intraoperative-intrapleural perfusion hyperthermo-chemotherapy for stage IVa invasive thymoma with myasthenia gravis]

A 37-year-old woman diagnosed with ocular myasthenia gravis was referred to our department. Chest computed tomography (CT) showed anterior mediastinal tumor and right pleural dissemination. Extended thymectomy and right intraoperative-intrapleural perfusion hyperthermo-chemothrapy (IPHC) were performed. Pathological diagnosis was invasive thymoma type B2 and stage IVa based on Masaoka's classification. The post operative course was uneventful. The patient underwent 4 cycles of adjuvant chemotherapy with doxorubicin, cisplatin, vincristine, and cyclophosphamide (ADOC), and is free from recurrence at 12 months postoperatively.

Associations between decay-accelerating factor polymorphisms and allergic respiratory diseases

BACKGROUND

Allergic diseases such as asthma and allergic rhinitis are major causes of morbidity in developed countries. The pathology underlying allergic respiratory diseases is considered to be IgE-mediated type I allergy characterized by mucosal inflammation that occurs in response to allergen exposure. They are common diseases involving a complex inheritance. Complement systems are known to play an important role in allergic diseases. Decay-accelerating factor (DAF) is important for the regulation of the complement system and is a good candidate for determining the susceptibility to allergic diseases.

OBJECTIVE

The present study aimed to investigate whether polymorphisms in the DAF gene are associated with allergic respiratory diseases in the Japanese population.

METHODS

We performed mutation screenings of DAF and conducted a tag single-nucleotide polymorphisms (SNP) association analysis for 684 unrelated adult individuals with seasonal allergic rhinitis (SAR) with Japanese ceder pollen, 188 mite-sensitive adults with asthma, and 346 unrelated non-allergic healthy controls.

RESULTS

DAF is located in the tight linkage disequilibrium (LD) block spanning 62 kb. The tag SNP analysis revealed that rs10746463 was significantly associated with SAR (P=0.00033) and mite-sensitive adult asthma (P=0.044). The rs2564978 and rs3841376 haplotypes, which are located in the promoter region of DAF, were in complete LD with rs10746463 (r2=1). Luciferase reporter assays with constructs containing the 5' flanking regions of DAF showed that the plasmid with rs2564978 C/rs3841376 deletion (the risk haplotype) had a statistically significantly lower transcriptional activity than that containing the rs2564978 T/rs3841376 insertion.

CONCLUSIONS

Our results suggest that DAF is one of the genes involved in conferring susceptibility to allergic respiratory diseases and show that decreased levels of DAF may be associated with the enhanced specific IgE responses occurring in allergic diseases in the Japanese population.

[Emergency operation due to complications of cardiac catheterization]

From January 2001 to July 2005, 4,741 cardiac catheterizations were performed on adult patients at our institute. Five of them underwent emergency operation due to complications of cardiac catheterization. The causes of operations were acute coronary occlusion due to coronary arterial dissection in 3 patients and bleeding due to perforation of the coronary artery in 2. Intra-aortic balloon pumping was used preoperatively in 4 patients and percutaneous cardio-pulmonary support in 2. Coronary artery bypass grafting was performed on all patients. Perforation sites of the coronary arteries were closed. One patient died 4 months after surgery, due to neurological damage, but the other 4 patients recovered and have been doing well. As coronary artery disruption is one of the main complications of cardiac catheterization, it is necessary to recognize the risk of hemodynamic derangement and to give prompt and appropriate treatment.

A novel diagnostic method for evaluation of vascular lesions in the digestive tract using infrared fluorescence endoscopy

BACKGROUND AND STUDY AIMS

We have developed an infrared fluorescence endoscope to evaluate gastrointestinal vascular lesions. Infrared endoscopy (IRE) after intravenous administration of indocyanine green (ICG) is used at present to examine vascular lesions such as esophageal varices. However, no previous study has compared the sensitivity of infrared fluorescence endoscopy (IRFE) with that of IRE. In this study, we compared the usefulness of IRFE and IRE.

PATIENTS AND METHODS

For IRFE we used an infrared endoscope equipped with excitation and barrier filters and an intensified charge-coupled device camera. In preliminary experiments, the observable tissue depth was assessed by wrapping increasing numbers of layers of commercially available pork around a syringe containing a uniform concentration of ICG or by changing the concentration of ICG in a syringe covered by a piece of pork of uniform thickness. In the clinical part of the study, ICG was administered intravenously at different concentrations to patients with esophageal varices and the resulting infrared fluorescent images were evaluated.

RESULTS

The preliminary experiments revealed that the depth of tissue that could be visualized was significantly greater in IRFE than it was in IRE (11.2 mm in IRFE vs. approximately 3.2 mm in IRE). Clear infrared fluorescence was obtained by IRFE at lower concentrations of ICG than the concentrations required to obtain clear images using IRE. In the clinical part of the study, clear infrared fluorescence was observed in a region where esophageal varices had been detected by conventional endoscopy when ICG was administered in doses of 0.005 mg/kg to 0.01 mg/kg, which was lower than the doses used in IRE.

CONCLUSIONS

Compared with conventional IRE, IRFE facilitated the observation of deeper layers, and esophageal varices were observed by IRFE following the intravenous administration of a markedly reduced dose of ICG. IRFE, in combining the characteristics of reflected infrared light and fluorescence, may be a useful novel procedure in the diagnosis of vascular lesions in the gastrointestinal tract.

[Two-stage repair of the transposition of great arteries with interruption/coarctation of the aorta]

We report on 10 patients who underwent two-stage repair of transposition of the great arteries (TGA) with interruption (IAA) or coarctation (CoA) of the aorta. First, an operation for aortic arch reconstruction was performed: Blalock-Park with pulmonary artery banding (PAB) for IAA (5 patients), subclavian flap with PAB for CoA (4 patients) and end-to-end anastomosis without PAB (1 patient). All survived the first operation and had no significant pressure gradient with good growth of the ascending aorta, except for the 1 case without PAB. Half of the 8 patients who underwent PAB developed migration of the PAB. The arterial switch operation (ASO) was performed 0.7-12.6 (5.6+/-4.7) months after the first surgery. One patient with an abnormal coronary artery tract was lost after ASO. Five developed pulmonary artery stenosis and 1 developed supra-aortic stenosis late after ASO. Two patients need reoperation, 1 for supra-aortic stenosis, and the other for reCoA. Two-stage repair for TGA with IAA/CoA is still a useful method with a good operative result. However, strict follow-up is necessary because of the high frequency of late morbidity.

[Mitral valve replacement 41 years after right pneumonectomy]

Mitral valve replacement was performed successfully on a 68-year-old patient who had undergone right pneumonectomy and thoracoplasty 41 years earlier. Preoperative pulmonary function tests revealed poor results; the forced vital capacity was 950 ml (28.0% of the predicted value) and the forced expiratory volume in 1 second was 750 ml (28.9% of the predicted value). Despite such poor pulmonary function, the patient tolerated the operation well and led uneventful course. Careful perioperative management to prevent pulmonary edema and aggressive postoperative pulmonary toilet to facilitate recovery of the pulmonary function seem important.

Experience with the Norwood procedure without circulatory arrest

OBJECTIVE

We evaluated a new cardiopulmonary bypass technique that allowed complete avoidance of circulatory arrest and deep hypothermia in the Norwood procedure for hypoplastic left heart syndrome.

METHODS

A total of 10 patients were included in this study. The arterial line of the cardiopulmonary bypass circuit was divided in two in a Y shape; one branch was used for cerebral perfusion through the innominate artery and the other for lower body perfusion through the cannula inserted into the descending thoracic aorta. Moderate hypothermia (29 degrees C-31 degrees C rectal temperature) and high pump flow (150-180 mL. kg(-1). min(-1)) were used. A valveless conduit between the right ventricle and the pulmonary artery was used in 6 patients as an alternative pulmonary blood source to a conventional Blalock-Taussig shunt (n = 4).

RESULTS

Circulatory arrest was completely avoided throughout the operation in all cases, and no complications from the new cardiopulmonary bypass technique were seen. Early deaths occurred in 3 cases. Neurologic deficits were not seen among the survivors, and the postoperative course was stable and uneventful, including satisfactory renal function.

CONCLUSIONS

The Norwood procedure for hypoplastic left heart syndrome was successfully accomplished with complete avoidance of circulatory arrest by means of cerebral perfusion through the innominate artery combined with cannulation of the descending aorta. A conduit between the right ventricle and the pulmonary artery seems an excellent alternative pulmonary blood source, although right ventricular function needs to be carefully monitored.

Synthesis of oligosaccharide with controlled sequence

A simple method for the synthesis of alternate heteropolysaccharide was investigated. Two types of modified glucose were combined into a cellobiose-type disaccharide monomer having only acetyl groups except a free hydroxyl group at C-3'. Polycondensation of this monomer, using stannic tetrachloride as catalyst, easily gave a novel copolysaccharide having regularly alternating 1,3-beta and 1,4-beta linkages.

Early and late results of total correction of congenital cardiac anomalies in infancy

OBJECTIVE

We evaluated long-term results of surgical correction of congenital cardiac anomalies in infancy.

METHODS

We reviewed cases of 856 patients who underwent complete correction of major cardiac anomalies in the first year of life during last 24 years at our institution, and analyzed results. Surgery involved ventricular septal defect (n = 453), tetralogy of Fallot (n = 92), atrioventricular canal defect (n = 93), and complete transposition of the great arteries (n = 218).

RESULTS

Operative mortality was 2.2% in ventricular septal defect, 0% in tetralogy of Fallot, 8.6% in atrioventricular canal defect, and 4.1% in complete transposition of the great arteries. Freedom from reoperation at 20 years was 96.5 +/- 2.0% and actuarial survival was 94.2 +/- 1.3% in ventricular septal defect. Freedom from reoperation at 15 years was 90.5 +/- 3.9% in tetralogy of Fallot and 86.6 +/- 4.4% in atrioventricular canal defect. Actuarial survival at 15 years was 97.8 +/- 1.6% in tetralogy of Fallot, 85.7 +/- 3.7% in atrioventricular canal defect, and 89.9 +/- 2.2% in complete transposition of the great arteries. Actuarial survival in complete transposition of the great arteries was significantly better in arterial than in atrial switch operations.

CONCLUSIONS

Total correction of ventricular septal defect, tetralogy of Fallot, atrioventricular canal defect, and complete transposition of the great arteries in infancy was conducted safely, but the incidence of reoperation in late follow-up must be reduced.

[Clinical laboratory data and reference intervals standardized in Fukuoka]

In Fukuoka whose population is approximately five million inhabitants, surveys on the accuracy of laboratory data have been performed by the Fukuoka Prefecture Medical Association for the last 30 years. We have been attempting to evaluate the data for routine use since 1988, and it has become possible to share laboratory data between all institutions in Fukuoka prefectures. As a result, reference intervals for 23 clinical chemistry analytes were established in 1995, to which were added in 1996 five serum protein constituents that have been utilized for clinical examinations. Methods for documentations and monitorings the data obtained in the prefecture were also established, standardization of the above analytes extended to 97% of the institutions in the prefecture. Results for 14 of the 23 clinical chemistry analytes have become highly reliable and clinically useful as differences between institutions in terms of results have narrowed. Standardization of other analytes is now in progress.

Successful staged-Fontan operation in a patient with ectopia cordis

Ectopia cordis is a very rare and often fatal disease. We report a successful surgery case of thoracoabdominal ectopia cordis with univentricular heart. This patient underwent a three-stage Fontan procedure, a right-modified Blalock-Taussig shunt at the age of 1 month, bidirectional Glenn shunt and pulmonary arterioplasty at 2 years 8 months, and finally a total cavopulmonary connection at 4 years. This patient was discharged from the hospital in good condition and has been doing well since. Thus, ectopia cordis is not a contraindication for a Fontan operation.

Standardization of Laboratory Data and Establishment of Reference Intervals in the Fukuoka Prefecture: A Japanese Perspective

Standardization of 22 clinical chemistry analytes and five serum protein constituents has been performed in the Fukuoka Prefecture, which has a population of approximately five million. The standardization project was established to determine reference intervals for these analytes by educating physicians, medical technologists and staff of medical institutions, and by daily or monthly monitoring the use of common control samples through e-mail. Standardization extended to 97% of the institutions in the prefecture. Results for 14 of the 22 clinical chemistry analytes have become highly reliable and differences between institutions decreased. Standardization of other analytes is now in progress. Regional collaboration based on international guidelines led to a significant improvement in interlaboratory comparability. Areas where further improvements are needed have been identified.

[Patching of the raw surface of the posterior right ventricular wall in Ross procedure to prevent bleeding and to confirm anastomosis of the conduit]

An 8-year-old boy underwent Ross procedure to repair aortic regurgitation and subaortic stenosis. In reconstruction of the right ventricular outflow tract, the raw surface of the right ventricular posterior wall was covered with autologous pericardial patch to prevent bleeding and to confirm the anastomosis of the pulmonary tract conduit made of expanded polytetrafluoroethylene. Bleeding from the posterior wall was absent and he led uneventful postoperative course. Same technique was used in 4 other patients, and satisfactory results were obtained. This technique, first reported from India, seems very useful in Ross procedure.

Successful implantation of a bipolar epicardial lead and an autocapture pacemaker in a low-body-weight infant with congenital atrioventricular block: report of a case

A permanent pacemaker system was successfully implanted into a low-body-weight infant with congenital atrioventricular (AV) block, using a bipolar epicardial CapSure Epi lead and an autocaptured Pacesetter Solus-micro VVIR pacemaker. The calculated life span of the pacemaker generator is 5 years with a heart rate of 120/min and an output of 1.2 V (0.31 ms), and fortunately, its threshold was autocaptured. Thus, we can conclude that the combination of a steroid-eluted bipolar epicardial lead and the smallest possible autocaptured pacemaker generator is most suitable for a neonate or young infant.

Mitral valve replacement using bileaflet mechanical prosthetic valve in the first year of life

OBJECTIVE

The operative management and long term outcome of mitral valve replacement in infancy remain a therapeutic challenge. The selection of a prosthetic valve for this particular age group might affect the clinical outcome. Here we present our experience of mitral valve replacement in 6 infants using small bileaflet mechanical prosthetic valves.

METHODS

Between January 1994 and August 1997, 6 infants (their age ranged from 3 months to 11 months, and their body weight from 2978 g to 7403 g) underwent mitral valve replacement using a mechanical valve prosthesis (16 mm CarboMedics prosthetic valve in 5, and 17 mm St. Jude Medical prosthetic valve Hemodynamic Plus in 1). The preoperative morphological features of the mitral valve were stenosis in 1, regurgitation in 3, and a combination of these in 2. The prosthesis was fixed at the annulus in 3, and at the supra-annular position in 3. Anticoagulation was performed using warfarin.

RESULTS

There was no operative mortality. Postoperative catheterization revealed an acceptable wedge pressure in the pulmonary arteries, ranging from 10 to 12 mmHg. During the mean follow-up period of 36 months, late death due to residual pulmonary hypertension occurred in 1 patient at 10 months after surgery. Excluding this patient, all remaining patients are doing well with no need for repeated operation with no thromboembolic complication. The actuarial survival rate and the reoperation free rate at 70 months are 83 +/- 15% and 100%, respectively.

CONCLUSION

Mitral valve replacement using a small size bileaflet mechanical prosthetic valves in infancy can be performed with low operative mortality and with satisfactory mid-term results.

Surgical treatment of tricuspid regurgitation caused by Löffler's endocarditis

A 25-year-old man with a history of bone-marrow-transplantation for the treatment of Löffler's endocarditis underwent surgery for massive tricuspid regurgitation with paroxysmal atrial flutter. Dense fibrosis in the right ventricular endocardium with complete obliteration of the apex was seen intraoperatively, and the right ventricular cavity was diminished. Annular dilatation of the tricuspid valve and entrapment of the posterior leaflet to the endocardial fibrosis were also seen. Annuloplication at the posterior leaflet was performed. In addition, the right atrial free wall was widely resected and the septal and inferior vena cava-tricuspid valve isthmi were cryoablated for the treatment of atrial flutter. Postoperative catheterization revealed rather high right ventricular end-diastolic pressure. However, tricuspid regurgitation disappeared with the increased cardiac output. Atrial flutter could not be induced by repetitive stimulation in the postoperative electrophysiological examination.

Norwood procedure without circulatory arrest

In the Norwood procedure for hypoplastic left heart yndrome, the distal descending thoracic aorta was cannulated just superior to the diaphragm through median sternotomy. In combination with cerebral perfusion through the graft anastomosed to the innominate artery, which was used as a systemic-to-pulmonary shunt later, this technique enabled us to completely avoid circulatory arrest and deep hypothermia throughout the operation.

Fate of atrial flap used in repair of total anomalous pulmonary venous connection

Histological changes in the right atrial flap used in repair of total anomalous pulmonary venous connection were observed when the patient underwent repair of peripheral pulmonary venous stenosis after two months. The flap, 35 mm in length and 15 mm in width, was thin and soft. Microscopically, endocardium and myocardium were preserved well, with only moderate thickening of the epicardium. We can anticipate the viability of the right atrial flap, but care should be taken to keep blood supply to the flap intact.

[Descending aorta perfusion through median sternotomy in primary repair of aortic interruption complex]

Circulatory arrest is frequently used in aortic arch reconstruction in pediatric cardiac surgery. However, risks of postoperative acute renal failure and neurological deficit can not be ignored. We performed primary repair of aortic interruption in one-month old girl. After commencing extracorporeal circulation with bicaval venous cannulae and with arterial cannulae into the pulmonary trunk and the innominate artery, the descending aorta was cannulated just superior to the diaphragm. The cannula in the pulmonary trunk was then removed. Arch reconstruction and closure of the ventricular septal defect were performed with continuous perfusion to the brain and the lower body. The extracorporeal circulation time and the aortic cross-clamp time were 117 min and 21 min, respectively. Postoperative renal function was excellent, and there was no finding of neurological deficit. Cannulation of the descending aorta is a simple and useful technique with safety, in arch reconstruction in infants.

[Clinical results of mitral valve surgery in children]

The clinical results of mitral valve surgery in children were evaluated. Fifty children (age ranged between 1 month and 12 years) with mitral valve regurgitation have undergone valve surgery with low operative mortality (2%). Valve plasty using several techniques including annuloplasty have been performed with quite high success rate (92%), while valve replacement was required in four patients who had the prolapse of the anterior mitral leaflet (8%). Reoperation was required in 5 patients (10%), and there were 4 late deaths. Introduction of the reconstructive technique of the chordae tendinae using artificial chordae resulted 100% success rate of mitral repair for the prolapse of the anterior mitral leaflet without death and reoperation. The reoperation free rate and the actuarial survival rate at 15 years of the patients with mitral regurgitation were 70 +/- 12% and 85 +/- 7%, respectively. In ten patients with mitral valve stenosis (age ranged between 1 month and 5 years), 5 patients required valve replacement (50%), and 2 patients died (20%). The clinical results of the surgery for the mitral stenosis were still unsatisfactory, and the reoperation free rate at 2 years was 42 +/- 30% and the actuarial survival rate at 13 years were 32 +/- 18%.

Mixed type of total anomalous pulmonary venous connection

BACKGROUND

The mixed type of total anomalous pulmonary venous connection is a rare condition in which some diagnostic and surgical problems still remain to be solved.

METHODS

In 9 patients a single pulmonary vein was connected to the systemic vein at a site different from the drainage site of the confluence of three other pulmonary veins. In 2 other patients, four pulmonary veins made a confluence which had two drainage sites. Correct diagnosis was made in all 7 patients who received cardiac catheterization but only in 5 of the 9 patients by color Doppler echocardiography. Total correction was performed in 3 patients and the single anomalous pulmonary vein was left uncorrected in 8 other patients.

RESULTS

There were two in-hospital deaths. Seven patients with a single residual anomalous pulmonary vein have been in good condition without clinical symptoms of congestive heart failure or pulmonary hypertension.

CONCLUSIONS

Diagnosis of mixed type of total anomalous pulmonary venous correction by echocardiography is sometimes difficult. When a mixed type is suspected, cardiac catheterization is recommended if the condition of the patient permits it. A single anomalous pulmonary vein may be left uncorrected without serious complications, but close observation is needed to prevent congestive heart failure and pulmonary vascular obstructive disease.

[Questionnaire of cryopreserved allograft valves in Kyushu and Yamaguchi area]

Japanese Society of Cryopreserved Thoracic Tissue Implantation was recently set up. Cryopreserved allograft valves are about to pervade in Japan. To clarify the interest, demands and supply of cryopreserved allograft valve in the area of Kyushu and Yamaguchi, we performed questionnaire investigation regarding this issue. Collection rate of this questionnaire was 87.5% (35/40 hospitals). Ninety-seven percent of the hospitals answered that they were interested in cryopreserved allograft. Ninety-four percent of the hospitals answered that they did not ethically hesitate to use cryopreserved allograft. Ninety-one percent of the hospitals hoped to perform cardiac surgery using allograft aortic valve if allograft is available. With respect to securing donors of allograft, two-third of the hospitals did not decide whether they could be involved in obtaining donors of allograft. As the number of the cadaver kidney donors is about 20 per year in the area of Kyushu and Yamaguchi, shortage of donors of allograft valve is anticipated.

Subaortic stenosis caused by anomalous papillary muscle of the mitral valve

We report on a rare case of subaortic stenosis caused by an anomalous posteromedial papillary muscle inserting directly into the anterior mitral leaflet, which had muscular extension to the subaortic region. Resection of the muscular extension alone was ineffective. A second operation including entire resection of the anomalous papillary muscle and mitral valve replacement resulted in successful relief of the obstruction. Microscopic findings of the resected tissue were compatible with those of hypertrophic cardiomyopathy.

[Staged repair for bilateral ductus arteriosus with pulmonary atresia and non-confluent pulmonary artery--a case report]

Staged operation was successfully performed in an infant with bilateral ductus arteriosus, and absence pulmonary artery. The first stage operation was performed at 2 months old of age. The left pulmonary artery was reconstructed using an equine pericardial roll sized 10 mm in diameter, and a 5 mm Dacron graft was anastomosed between the left subclavian artery and the roll as an aortopulmonary shunt. In the second stage, the same procedure was done on the right side at eight months of age. In the last stage, the patient underwent Rastelli procedure at 2 years old of age. The central pulmonary artery was created with a ring forced EPTFE graft above the ascending aorta, and a Carpentier-Edwards valved conduit (14 mm) was anastomosed between the right ventricle and the EPTFE graft. Post operative course was uneventful. We consider that the staged procedure including the pulmonary artery reconstruction and the aortopulmonary shunt on both sides is recommended in the case of absent central pulmonary artery in infant.

Postoperative cardiac rhythms with superior-septal approach and lateral approach to the mitral valve

BACKGROUND

The superior-septal approach provides an excellent view of the mitral valve and therefore has received considerable interest. However, the safety of this approach is controversial because it requires division of the sinus node artery in most cases.

METHODS

Postoperative cardiac rhythms were analyzed in 152 consecutive patients who underwent mitral valve procedures between January 1992 and February 1995 with a conventional right lateral left atriotomy (group 1, n = 69) or the superior-septal approach (group 2, n = 83). Follow-up ranged from 2 to 38 months, and the mean follow-up was 16.1 months in group 1 and 13.8 months in group 2.

RESULTS

The mortality rate was similar in the two groups (1.4% in group 1 and 1.2% in group 2), and the causes of death were not related to the left atriotomy. At discharge, 96% of the patients in group 1 who were in sinus rhythm preoperatively and 78% of those in group 2 remained in sinus rhythm. At the last follow-up, 88% of these patients in group 1 and 83% in group 2 remained in sinus rhythm. Among the patients in atrial fibrillation or junctional rhythm before operation, 12% in group 1 and 11% in group 2 had regained sinus rhythm at the last follow-up. There were no significant differences in these values.

CONCLUSIONS

Although the incidence of dysrhythmias was higher with the superior-septal approach in the early postoperative period, this approach provides an excellent operative view of the mitral valve and similar results in terms of late postoperative cardiac rhythms as the right lateral left atriotomy.

Selective cerebral perfusion technique during aortic arch repair in neonates

We describe selective cerebral perfusion techniques for repair of the aortic arch in neonates. These techniques may help protect the brain from ischemic injury caused by a cessation of cerebral perfusion for aortic arch reconstruction in patients with hypoplastic left heart syndrome or interrupted aortic arch.

[Surgical results of valvuloplasty for common atrioventricular valve regurgitation in single ventricle]

From 1988 through 1994, 18 patients who had common atrioventricular valve regurgitation associated with single ventricle underwent valvuloplasty. All patients had isomerism heart (right isomerism: 16, left isomerism: 2). The preoperative degree of regurgitation was 3.3 +/- 0.4 (Sellers). Valvuloplasty was performed by two different procedures. Semi-circular annuloplasty was used in nine patients. Dividing the common atrioventricular valve orifice into two parts (bivalvation) with or without annuloplasty was used in nine. The concomitant procedures varied: three patients underwent systemic pulmonary shunt, two underwent repair of total anomalous pulmonary venous drainage, one underwent pulmonary arterial banding, five underwent bidirectional Glenn, shunt, and four underwent Fontan operation. One early death and three late deaths have occurred. The early postoperative degree of regurgitation was reduced to 1.3 +/- 1.0. In nine patients, however, the degree of regurgitation increased late postoperatively. Seven patients were reoperated on because of regurgitation: three patients had valve replacement and four had reannuloplasty. Increased incidence of deterioration of regurgitation in late period was seen in patients under 2 years old and those receiving a concomitant Blalock shunt. Lower event-free rate after 2 years was seen in patients with double inlet right or indeterminate ventricle and those underwent the annuloplasty alone. We conclude that the dividing common atrioventricular valve orifice into two parts with annuloplasty could effectively reduce the regurgitation in most patients with isomerism heart, and the concomitant ventricular unloading operation seems to offer promise for improving long-term results.

[Postoperative pulmonary stenosis after arterial switch operation, comparison in three methods of pulmonary reconstruction: modified Pacifico, autologous pericardial patch, and equine pericardial patch]

To prevent postoperative pulmonary stenosis in arterial switch operation for transposition of the great arteries, pulmonary reconstruction without patch augmentation (modified Pacifico method: Pa-group) and reconstruction using W-shaped fresh autologous pericardium (AW-group) were introduced instead of the former method using equine pericardium (XW-group). Postoperative pulmonary stenosis (RV-PA pressure gradient greater than 30 mmHg) was not seen among the 17 cases in the Pa-group (0%), and was seen in 2/14 (14.3%) in the AW-group and in 4/14 (29%) in the XW-group. Progressive increase in pressure gradient was seen in the XW-group in the midterm cardiac catheterization (p < 0.01), but such tendency was not observed in the Pa-group and the AW-group. Sectional area at the pulmonary valve ring, at the anastomotic site in the main pulmonary artery, and at the pulmonary branches just distal to the bifurcation, standardized by the body surface area, increased in the Pa-group and the AW-group, but were unchanged or slightly decreased in the XW-group in the midterm cardiac angiography. We believe that postoperative pulmonary stenosis can be best avoided if modified Pacifico method is used. The cases in which postoperative pulmonary stenosis or coronary artery compression is anticipated such as those with side-by-side aortopulmonary relationship or after pulmonary artery banding, should be operated upon using fresh autologous pericardial patch.

[Valve replacement in an infant with congenital mitral stenosis--report of a case which showed hemodynamics similar to that of hypoplastic left heart syndrome in neonatal period]

In the neonatal period, the patient showed severely hypoplastic left ventricle, severe mitral stenosis, patent foramen ovale and patent ductus arteriosus with right-to-left shunting, which resulted in the hemodynamics similar to that of hypoplastic left heart syndrome. However, progressive left ventricular growth was recognized after spontaneous closure of the foramen ovale, and the cardiac catheterization at the age of 6 months revealed almost normal left ventricular volume and systolic forward flow from the left ventricle to the descending aorta. The operation was performed at the age of 7 months under cardiopulmonary bypass with moderate hypothermia and cardiac arrest. The mitral leaflets were thickened and dysplastic, two short papillary muscles were hypertrophic and very closely related, and the chordae were extremely short and fused each other making the interchordal space obstructed. Because the mitral annular diameter (13 mm) was too small for conventional valve replacement, the prosthetic valve (CarboMedics #16) was sewn to the left atrial wall 5 to 10 mm above the mitral annulus. The ductus arteriosus was ligated. The postoperative cardiac catheterization showed residual pulmonary hypertension, but pulmonary vascular response to oxygen-inhalation was recognized. We consider that there were two important hemodynamic factors which led to successful biventricular repair in this case. First, early spontaneous closure of the foramen ovale accerelated the left ventricular growth and prevented right ventricular failure resulting from increased pulmonary blood flow. Second, considerable part of the systemic output was supplied through a large ductus arteriosus, and thus over-systemic pulmonary hypertension was avoided.

[Reoperation for transposition of the great arteries: mid-term results and reoperation after arterial switch operation]

The arterial switch operation for transposition of the great arteries is now widely accepted as the therapeutic method of choice. As of December 1993, a total of 162 patients underwent the arterial switch. There were 100 patients with transposition and intact ventricular septum, 48 with a ventricular septal defect, 14 with ventricular septal defect and arch anomalies (coarctation: 11, interruption: 3). Early and late mortality were 3.7% (6 patients) and 4.5% (7 patients), respectively. Postoperative pulmonary stenosis (> 30 mmHg) was noted in 33 patients (22%), aortic regurgitation (> mild) in 20 (13%), supravalvular aortic stenosis (> 20 mmHg) in 5 (3%) and mitral regurgitation (> mild) in 5 (3%). Reoperation was performed in 27 patients with no mortality. Mean interval between the switch and the reoperation was 30 months. Twenty-three patients with pulmonary stenosis underwent patch plasty of pulmonary artery. Two children with severe aortic regurgitation underwent aortic valve replacement. Two patients who had undergone one-staged repair for interruption complex were reoperated due to supravalvular aortic stenosis and pulmonary stenosis. Actuarial survival and freedom from reoperation at 9 years were 90% and 69%, respectively.

[Rigidity abolished by intravenous dantrolene in a patient with Parkinson's disease under spinal anesthesia]

Spinal anesthesia was given to a patient with right femur fracture and Parkinson's disease (PD). Although sufficient analgesia was obtained up to L1 level after spinal anesthesia, the muscular rigidity remained. Furthermore, tremor of the upper extremities continued. After administering dantrolene sodium (DT) intravenously, these untoward features were abolished. These findings suggest that DT abolishes rigidity and tremor in PD, and is useful for the management of anesthesia for a patient with PD.