Lath formation mechanisms and twinning as lath martensite substructures in an ultra low-carbon iron alloy.

Lath martensite is the dominant microstructural feature in quenched low-carbon Fe-C alloys. Its formation mechanism is not clear, despite extensive research. The microstructure of an Fe-0.05 C (wt.%) alloy water-quenched at various austenitizing temperatures has been investigated using transmission electron microscopy and a novel lath formation mechanism has been proposed. Body-centered cubic {112}〈111〉-type twin can be retained inside laths in the samples quenched at temperatures from 1050 °C to 1200 °C. The formation mechanism of laths with a twin substructure has been explained based on the twin structure as an initial product of martensitic transformation. A detailed detwinning mechanism in the auto-tempering process has also been discussed, because auto-tempering is inevitable during the quenching of low-carbon Fe-C alloys. The driving force for the detwinning is the instability of ω-Fe(C) particles, which are located only at the twinning boundary region. The twin boundary can move through the ω ↔ bcc transition in which the ω phase region represents the twin boundary.

Recent refinements of glissonean pedicle approach for liver resection / Шинэ санаа Шинэ нээлт

Background: The glissonean pedicle approach was introduced by Couinaud and Takasaki in the early 1980s. The key of the glissonean pedicle approach is clamping the pedicle first, secondly confirming the territory, and finally dissecting the liver parenchyma. In this presentation, we introduced our recent refinements of glissonean pedicle approach for liver resection. “Approach to the glissonean pedicles at the hepatic hilus” Couinaud described three approaches to the hepatic hilus. 1) Intra-fascial access (Control method): The conventional dissection at the hilus or within the sheath is referred to as intrafascial access However, dissection performed under the hilar plate is dangerous and surgeons have to consider any variations of the hepatic artery and bile ducts. 2) Extra-fascial access (Glissonean pedicle approach): The glissonean pedicle is dissected from the liver parenchyma at the hepatic hilus before dissecting the liver parenchyma. This procedure prevents intrahepatic metastasis of HCC, which spreads along the portal vein and improves the overall survival after surgery. 3) Extra-fascial and transfissural access: If the main portal fissure or the left suprahepatic fissure is opened after dissecting the liver parenchyma, the surgeon can confirm the pedicles that arise from the hilar plate or the umbilical plate. “Operative techniques” 1) Preoperative 3D simulation of the precise anatomy of portal vein, hepatic artery and bile duct at hepatic hilus should be performed. 2) Right glissonean pedicle: The hilar plate is detached from the quadrate lobe. The assistant pulls the liver parenchyma cranially and the operator conversely pulls the hepatoduodenal ligament caudally. Mayo scissors are inserted along the liver parenchyma between the liver parenchyma and glissonean capsule (Fig.1). Then forceps are inserted in the same way and the right main pedicle is taped (Fig.2). The right anterior and posterior glissonean pedicles are taped as well. 3) Left glissonean pedicle: The hilar plate is detached from the liver parenchyma. Then, the Arantius duct is confirmed and the left pedicle is dissected along the left pedicle at the ventral side of the Arantius duct. “Pitfall of glissonean pedicle approach” The right pedicle should be dissected in the liver side as much as possible to prevent the injury of left hepatic duct. If possible, the right pedicle is recommended to be dissected at the level of the second branches separately (Fig.3). The right posterior hepatic duct sometimes branches from the left hepatic duct and the Arantius duct is confirmed and the left pedicle should be dissected along the left pedicle at the ventral side of the Arantius duct because the right posterior hepatic duct branches from the left hepatic duct at the dorsal side of Arantius’ duct. In addition, the intraoperative cholangiogram should be used in the case with the abnormal anatomy of bile duct. Conclusions: Any anatomical hepatectomy can be performed using “glissonean pedicle approach” which allows simple, safe and easy liver resection.

[Application of the lower partial sternotomy approach to patients who may need tracheostomy in the early period after cardiac surgery].

Recent good results of cardiovascular surgery have led to expansion of its indication to elderly patients and patients with serious complications. Such patients may have serious respiratory complications after cardiac surgery and need to undergo tracheostomy relatively early in the postoperative period. Although the full sternotomy approach is the standard in almost all cardiac surgeries, superficial and deep sternal infections are rather common after early tracheostomy in full sternotomy patients. The lower partial sternotomy approach is a safer and more useful procedure in patients who will need tracheostomy in the early period after cardiac surgery. We report on 2 patients who were successfully tracheostomized within a week after cardiac surgery, with a review of the literature.

Compressive properties of cartilage-like tissues repaired in vivo with scaffold-free, tissue engineered constructs.

BACKGROUND: It is crucial to develop an effective methodology for restoring adequate compressive properties to osteoarthritic cartilage. We have developed a scaffold-free tissue engineered construct cultured from synovium-derived mesenchymal stem cells. However, the compressive properties of cartilage-like tissues repaired with the construct have not been fully determined. METHODS: Synovium-derived mesenchymal stem cells were cultured in Dulbecco's modified Eagle's medium to produce the tissue engineered construct. Implantation of the construct into cylindrically-shaped partial defects in femoral cartilage in an experimental porcine model was performed. Six months after implantation, cartilage-like tissues repaired with the construct were subjected to static and cyclic compression tests using a micro-unconfined compression test apparatus developed in our laboratory. FINDINGS: The developed apparatus was validated in preliminary examinations. The repaired tissues exhibited rate-dependent viscoelastic properties; the compressive modulus was slightly lower than that of normal cartilage at a rate of 4 microm/s, while no difference was observed at a rate of 100 microm/s. In contrast, the repaired tissue without the construct exhibited rate-independent, non-viscoelastic properties. In the cyclic compression test, however, the compressive strain was significantly larger in both repaired tissues as compared with normal cartilage. INTERPRETATION: Although the quasi-static compressive properties of the repaired tissue with the construct, indicating rate-dependent and viscoelastic behaviors, are comparable to normal cartilage, the cyclic compressive strain increases more rapidly than in normal cartilage. It is suggested that the differences between the tissues and normal cartilage are attributable to the increased permeability of the extracellular matrix.

3D Imaging System for Visualizing and Monitoring Patients.

Three-dimensional (3D) visualization or 3D monitoring of patients or infected animals is useful in actual clinical environment. We propose a 3D imaging system with a single camera and multiple mirrors. The camera is located directly above the object and the multiple mirrors are placed surrounding the object. The single captured image includes multiple viewpoint images: the object captured directly and the same objects reflected by the mirrors. After a simple calibration of the measurement, the 3D volume data are reconstructed with the visual hull based method. Texture mapping is also performed to enhance the reality. A living object was observed in usual environment using this system. The results have demonstrated effectiveness of the system.

Endobronchial ultrasonography with guide-sheath for peripheral pulmonary lesions.

The usefulness of endobronchial ultrasonography (EBUS) with guide-sheath (GS) as a guide for transbronchial biopsy (TBB) for diagnosing peripheral pulmonary lesions (PPL)s and for improving diagnostic accuracy was evaluated in this study. EBUS-GS-guided TBB was performed in 24 patients with 24 PPLs of < or =30 mm in diameter (average diameter=18.4 mm). A 20-MHz radial-type ultrasound probe, covered with GS was inserted via a working bronchoscope channel and advanced to the PPL in order to produce an EBUS image. The probe with the GS was confirmed to reach the lesion by EBUS imaging and X-ray fluoroscopy. When the lesion was not identified on the EBUS image, the probe was removed and a curette was used to lead the GS to the lesion. After localising the lesion, the probe was removed, and TBB and bronchial brushing were performed via the GS. Nineteen peripheral lesions (79.2%) were visualised by EBUS. All patients whose PPLs were visible on EBUS images subsequently underwent an EBUS-GS-guided diagnostic procedure. A total of 14 lesions (58.3%) were diagnosed. Even when restricted to PPLs <20 mm in diameter, the diagnostic sensitivity was 53%. In conclusion, endobronchial ultrasonography with guide sheath-guided transbronchial biopsy was feasible and effective for diagnosing peripheral pulmonary lesions.

Microarray analysis of human milk cells: persistent high expression of osteopontin during the lactation period.

To continue the search for immunological roles of breast milk, cDNA microarray analysis on cytokines and growth factors was performed for human milk cells. Among the 240 cytokine-related genes, osteopontin (OPN) gene ranked top of the expression. Real-time PCR revealed that the OPN mRNA levels in colostrum cells were approximately 100 times higher than those in PHA-stimulated peripheral blood mononuclear cells (PBMNCs), and 10 000 times higher than those in PB CD14(+) cells. The median levels of OPN mRNA in early milk or mature milk cells were more than three times higher than those in colostrum cells. Western blot analysis of human milk showed appreciable expression of full-length and short form proteins of OPN. The concentrations of full-length OPN in early milk or mature milk whey continued to be higher than those in colostrum whey and plasma as assessed by ELISA. The early milk (3-7 days postpartum) contained the highest concentrations of OPN protein, while the late mature milk cells (1 years postpartum) had the highest expression of OPN mRNA of all the lactating periods. The results of immunohistochemical and immunocytochemical staining indicated that OPN-producing epithelial cells and macrophages are found in actively lactating mammary glands. These results suggest that the persistently and extraordinarily high expression of OPN in human milk cells plays a potential role in the immunological development of breast-fed infants.

[Prostacyclin oral internal therapy for severe pulmonary hypertension after total correction of cor triatriatum with partial anomalous pulmonary venous return; report of a case].

A 37-day-old girl having cor triatriatum with partial anomalous pulmonary venous return was found on emergent admission. Echocardiography and angiography revealed severe pulmonary hypertension with anomalous pulmonary venous return to inominate vein. She still was in respiratory failure after emergent surgical repair because of severe pulmonary hypertension following pulmonary venous obstruction. Prostacyclin is the first Food and Drug Administration (FDA)-approved treatment for advanced primary pulmonary hypertension, which has antithrombotic properties related to its effect on platelets and is a potent vasodilator of both the systemic and pulmonary arteries, and has positive inotropic properties. We started prostacyclin oral internal therapy for her and she recovered from respiratory problems very quickly. Prostacyclin might be effective for pulmonary hypertension before and after surgical repair as primary pulmonary hypertension.

Laparoscopic lumbar sympathectomy for lower-limb disease.

BACKGROUND: The standard procedure for sympathectomy is open surgery. The oblique retroperitoneal approach is popular because it provides good visibility, albeit at the expense of requiring a long skin incision. Chemical sympathectomy has been introduced as a less invasive means of achieving sympatholysis; however, this method is also associated with a significant incidence of incomplete block and transient denervation. Laparoscopic surgery is a new approach that simplifies various surgical procedures. The aim of our report was to evaluate the benefits of endoscopic retroperitoneal surgery for lumbar sympathectomies. METHODS: Between March 1997 and April 2000, seven patients underwent laparoscopic lumbar sympathectomy in our department (all men, with an average age or 45.1 years). The predominant presenting symptoms were unilateral pain at rest and lower-extremity coldness. Symphaectomy was performed using a retroperitoneal approach on six patients and an anterior transperitoneal approach on one patient. After laparoscopic lumbar sympathectomy, skin thermometry was carried out on all patients. RESULTS: The postoperative skin temperature of the affected leg rose to 36.6 +/- 0.5 degrees C, as compared to 33.8 +/- 0.8 degrees C preoperatively. After laparoscopic lumbar sympathectomy, none of the patients complained of neuralgia. All patients achieved sustained symptomatic relief, and no major postoperative complications were noted. CONCLUSIONS: Lumbar sympathectomy can be performed laparoscopically. Currently, our standard technique is the retroperitoneal approach. More clinical experience and long-term follow-up will ultimately determine if this will become the procedure of choice. However, we believe that a learning period is necessary for this technique to be fully mastered.

Strut fracture of Björk-Shiley convexo-concave valve in Japan--risk of small valve size--.

BACKGROUND: The Björk-Shiley convexo-concave (BSCC) prosthetic valve was introduced in 1979. Between 1979 and 1986, approximately 86,000 BSCC valves were implanted. By December 31, 1994, 564 complete strut fractures had been reported to the manufacture. We experienced a case of an outlet strut fracture and investigated the risk of BSCC prosthetic valve fractures in Japan. METHODS AND RESULTS: To investigate the risk factor of a strut fracture in Japan, we investigated published cases of strut fractures. Between 1979 and 1986, 2021 BSCC valves were implanted in Japan. By January 31, 2000, 11 complete strut fractures of 60-degree BSCC valves including our case had occurred. The patients were eight males and three females. The average age at valve replacement was 42.4+/-8.1 years, and nine of eleven (81.8%) were patients < 50 years-old. The average age of the patients when the BSCC valve fractured was 47.7+/-6.4 years, and eight of eleven (72.7%) were patients <= 50 years old. All patients were implanted in the mitral position. The sizes of the BSCC valve were 27 mm (n=5) (45.5%), 29 mm (n=3) (27.2%), and 31 mm (n=3) (27.2%). Four patients died and seven patients survived. CONCLUSIONS: Although only 11 BSCC valve struts fractured and statistical analysis could not be performed, our findings suggest that the high risk group for a strut fracture in Japan is young male patients with a mitral valve, >= 27 mm in size with BSCC models manufactured before March 1982. When following-up patients with BSCC models manufactured before March 1982, the possibility of a strut fracture in all BSCC valve sizes should be kept in mind.

[HANP infusion therapy for early infants with congestive heart failure after surgical repair].

We report about successful case of human atrial natriuretic peptide (HANP) infusion therapy for early infants who developed congestive heart failure after surgical repair of congenital heart diseases at Ehime Prefectural Central Hospital between January, 1998 through January, 2000. Age at operation ranged from 0 day to 38 days (mean 20 days), and body weight ranged from 1.6 kg to 3.5 kg (2.8 kg as mean). Following HANP infusion at incremental doses of 0.05 to 0.24 microgram/kg/min (0.16 microgram/kg/min as mean), urine output and hemodynamics dramatically improved. Urine output increased from 0.75 ml/kg/hr to 2.79 ml/kg/hr (p = 0.0001) and good urinary output was maintained (3.06 ml/kg/hr) even after discontinuation of the infusion. During the infusion, the heart rate decreased from 157 bpm to 150 bpm and the systemic systolic blood pressure increased from 68 mmHg to 78 mmHg. Central venous pressure decreased from 9.3 mmHg to 7.9 mmHg. There were no adverse effects by HANP infusion. These are successful cases of HANP infusion therapy as the initial treatment of post-operative pulmonary hypertension in this age group. Human atrial natriuretic peptide infusion therapy can be used safely and might be useful in some early infants with CHF, although more investigation is needed.

[The effect of milrinone administrated before weaning from cardiopulmonary bypass in adult cardiac surgery].

We investigated the effect of milrinone (phoshphodiesterase III inhibitor) on postoperative hemodynamics in adult eighteen cardiac surgical patients (mean LVEF = 63%). Milrinone was administrated just after the aortic declamping during CPB. Comparing with control group, systemic vascular resistance decreased significantly and sufficient inotropic effect was sustained. In order to keep proper blood pressure much more cathechoramine dose was need when milrinone dose increased during this study. This is supposed that milrinone affected strong vasodilating effect and caused relative hypovolemic condition to the patient who showed good cardiac function. Milrinone causes best efficacy to the patient of poor cardiac function when he showed deconpensation or relatively hypervolemic hemodynamic condition.

Human atrial natriuretic peptide infusion for a neonate with congestive heart failure after total correction of total anomalous pulmonary venous connection.

A successful case of human atrial natriuretic peptide (HANP) infusion therapy for a neonate who developed congestive heart failure (CHF) after total repair of total anomalous pulmonary venous connection was performed on the first day of life. Following 14h of HANP infusion at incremental doses of 0.125-0.25 microg x kg(-1) x min(-1) urine output and hemodynamics dramatically improved. Urine output increased from 1.1 to 10.6 ml/h (p<0.0001) and good urinary output (13.0 ml/h) was maintained even after discontinuation of the infusion. During the infusion, the heart rate decreased from 166 to 152 beats/min (p<0.0001), and the systemic systolic blood pressure increased from 82 to 103 mmHg (p<0.0001). Central venous pressure was not significantly affected by HANP infusion. This is the first successful case of HANP infusion therapy as the first treatment of post-operative pulmonary hypertension in this age group. This therapy can be used safely and may be useful in neonates with CHF resulting from other causes, but more investigation is needed.

Invagination induced by a long intestinal tube: report of a case.

Invagination induced by a long intestinal tube is rarely encountered. We report herein one such case of a 62-year-old man who was successfully treated by laparoscopically reducing the invagination, then performing partial resection of the small intestine.

Effects of docarpamine on hemodynamics after open heart surgery in children.

Docarpamine is a dopamine prodrug which has been selected from a large number of dopamine derivatives in order to develop an orally effective dopamine. The pharmacokinetics after oral administration of docarpamine have not yet been studied in children undergoing open heart surgery. This study examined the effects of docarpamine on hemodynamics and evaluated its safety in 11 children undergoing open heart surgery for congenital heart disease. This study began when the patientOs postoperative condition was stabilized by continuous dopamine infusion into the vein at a rate of 5 micro g/kg/min. The patients were administered 40 mg/kg of docarpamine every 8 hours, and hemodynamics were measured every 4 hours for 16 hours after the initial docarpamine administration. Immediately after the initial docarpamine administration, the dose of dopamine was reduced to 3 micro g/kg/min. Infusion of dopamine was stopped 8 hours after the initial docarpamine administration. Systemic systolic and diastolic blood pressure and heart rate showed no significant changes. Mean right atrial pressure decreased 4 hours after docarpamine administration. Mixed venous oxygen saturation and mean velocity of circumferential fiber shortening increased significantly after docarpamine administration. No significant changes were observed in urine volume. All patients could be weaned from dopamine within 8 hours. No changes were observed in ECG, and no arrhythmia-inducing action was noted. Our study indicates that 40 mg/kg oral doses of docarpamine produce plasma dopamine concentration equivalent to those of a 3 to 5 micro g/kg/min dopamine infusion. Our data suggest that docarpamine is a safe and effective drug for children who have undergone open heart surgery.

[Total anomalous of pulmonary venous connection in infants less than 3 months old].

We examined the surgical results of total anomalous pulmonary venous connection (TAPVC) retrospectively in 6 infants, who were less than 3 months old and underwent a total repair at Ehime Prefectural Central Hospital between May, 1993 through May, 1998, in terms of the pre, peri, and postoperative management, the site of connection, and the surgical procedures. Aged at operation ranged from 1 day to 86 days (mean 39 days), and body weight ranged from 2.4 kg to 5.5 kg (mean 3.4 kg). All 6 patients had echocardiographic diagnosis and cardiac catheterization but one. In operative procedure, cut back method was done in a patient of paracardiac type of Darling's classification and posterior approach was used in total correction for 4 supracardiac and 1 infracardiac type. There were 3 hospital deaths who had poor conditions before operation, but no late deaths. Surgical results of TAPVC might have been improved with advances in non-invasive diagnosis by echocardiography, and pre and perioperative management. And we should take care of these patients of TAPVC in long term period to make sure that they have no pulmonary venous obstruction.

A surgical case of atypical aortic coarctation using cardiopulmonary bypass.

We report a 44-year-old woman with atypical aortic coarctation accompanied by cerebral artery disease. She was hospitalized for vertigo. An extra-anatomic bypass between the ascending aorta and abdominal aorta was performed using partial cardiopulmonary bypass under moderate hypothermia to reduce the after load of the left ventricle and maintain cerebral blood flow and cerebral perfusion pressure. The postoperative course was uneventful and there was no postoperative neurological deficiency.

Combined catheter embolization and femorofemoral bypass for pseudoaneurysm of the right external iliac artery: report of a case.

Performing direct surgery for postoperative hemorrhage caused by intraperitoneal arterial injury is very difficult. We report herein the case of a 52-year-old woman who developed sudden right lower abdominal pain after numerous laparotomies and radiotherapy for advanced uterine cancer. A diagnosis of pseudoaneurysm of the right external iliac artery was made, and an emergency catheter embolization and femorofemoral bypass was successfully performed under local anesthesia. The patient was able to walk the next day. To the best of our knowledge, this is the first report of such a combined procedure in the literature.

Utilization of a model lung system to assess the effects of an inspiratory impedance threshold valve on the relationship between active decompression and intra-thoracic pressure.

Use of an inspiratory impedance valve has recently been shown to increase the efficacy of standard and active compression-decompression cardiopulmonary resuscitation. We evaluated the effects of a prototypic impedance valve on the relationship between the active decompression and intra-thoracic pressure using a mechanical model lung system. Intermittent impedance to inspiratory flow of respiratory gases during the decompression phase of active compression-decompression cardiopulmonary resuscitation significantly decreased the intra-thoracic pressure, while the pressure was almost zero cm H2O during the cardiopulmonary resuscitation cycle when the impedance threshold valve was not functioning. Thus, this mechanical model will help in evaluating the valve as well as in optimizing its function by simulating various forms of lung disease.