Biomedical subjects
H Ueda
Publications and source records attributed to H Ueda.
[VCG of tetralogy of Fallot].
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[Radioisotope diagnosis of lung diseases].
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Morphologic analysis of common atrioventricular valves in patients with right atrial isomerism.
The objective of the study was to examine the relation between the morphology of the common atrioventricular valve and regurgitation of the valve in patients with right atrial isomerism. We examined seven consecutive patients with documented right atrial isomerism who subsequently underwent postmortem examination during a 10-year period. The degree of regurgitation and the diameters of the common valve were evaluated via cineangiography, and the site of regurgitation was evaluated by echocardiography. The morphology of the common atrioventricular valve was assessed further at autopsy. Cineangiography revealed valve diameters ranging from 14.8 to 27.8 mm (mean 20.9 mm). Valvar regurgitation was revealed within 2 months of birth in all patients. Regurgitation abruptly worsened in three patients after placement of a Blalock-Taussig shunt or a central shunt and postintubation. Autopsies revealed that the common atrioventricular valve consisted of four leaflets in five patients, and three leaflets in two. The anterior leaflets were large and protruding in all patients, and the lateral leaflets were thickened in six. All patients had a mass consisting of the left lateral leaflets and chordae with direct attachment of the chordae to the ventricular muscle (the right lateral leaflet was attached to the ventricular muscle and immobile in one patient). The lateral leaflets clung to the ventricular wall and exhibited poor movement in six patients. Leaflets with poor mobility corresponded to the regurgitant valvar site as assessed by echocardiography in six patients; and the regurgitation in three patients with acute deterioration occurred at the valvar side with poor mobility. It is concluded that the common atrioventricular valve in patients with right atrial isomerism has morphologic characteristics that may be associated with valvar regurgitation and malignant potential for abrupt deterioration after replacement of systemic-pulmonary shunting.
EUS and ERCP features of nonalcoholic duct-destructive, mass-forming pancreatitis before and after treatment with prednisolone.
Nonalcoholic, duct-destructive, mass-forming pancreatitis in a 28-year-old man was presented with endoscopic ultrasonographic (EUS) and endoscopic retrograde cholangiopancreatographic (ERCP) findings before and after corticoid therapy. Because this disease is often mistaken for a malignant tumor, EUS combined with ERCP may provide imaging characteristics useful for differentiation from malignant tumor, for early diagnosis, and for monitoring therapeutic effects.
Importance of serum cholesterol level in development of diabetic autonomic neuropathy.
Changes of cardiac beat-to-beat variation (BBV)--an index of autonomic nerve function--were examined on 2 occasions in an interval of 3.7-5.9 years in 33 diabetics. A total of 204 healthy people, ranging from 11 to 88 years of age, were also subjected to the BBV measurement as controls. In diabetics, a lower rate of change of BBV than the control value was considered as deterioration. Glycohemoglobin was measured every month. The mean of serum cholesterol on the 2 occasions nearest to each time BBV examination was taken for the evaluation of cholesterol level. No significant difference was observed in the control state of blood glucose in terms of glycohemoglobin between the groups with and without BBV deterioration. In 20 subjects with normal cholesterol level, 11 showed a BBV deterioration, and in 13 subjects with abnormal cholesterol level 12 deteriorated in BBV. Therefore, diabetics with normal serum cholesterol level did not seem to exacerbate autonomic neuropathy in terms of BBV.
Non-opioid analgesia of the neuropeptide, neo-kyotorphin and possible mediation by inhibition of GABA release in the mouse brain.
The novel neuropeptide, neo-kyotorphin, produced a naloxone-resistant analgesia in the tail pinch test when given (IC) to mice. Pretreatments with implantation of a morphine pellet or with phentolamine (10 micrograms IT) or with reserpine (10 mg/kg SC) did not attenuate this analgesia, yet the analgesia was antagonized by GABA mimetics, such as muscimol (0.1 microgram IC), nipecotic acid (100 mg/kg IP). Neo-kyotorphin inhibited the Ca2+-dependent and depolarization-evoked release of 3H-GABA, from crude synaptosomes of the lower brain stem of rats. These findings suggest that inhibition of GABA in the brain may in part be involved in neo-kyotorphin-induced analgesia.
Low-dose mitomycin C, etoposide, and cisplatin for invasive vulvar Paget's disease.
We report the effect of low-dose mitomycin C, etoposide, and cisplatin (low-dose MEP) therapy for three patients with invasive vulvar Paget's disease (invasive VPD) who declined radical vulvectomy and skin grafting. One patient achieved a complete response, while the other two showed partial responses (PR) without grade 3 or 4 adverse effects. The two patients with PR were undergone partial vulvectomy and inguinal lymph node dissection. All patients have no sign of recurrence for 10 months after chemotherapy. Our present results suggest that low-dose MEP is an effective and safe chemotherapy for invasive VPD and low-dose MEP may significantly improve postoperative quality of life in patients with invasive VPD by avoiding extensive vulvar resection and skin grafting.
Effect of beta-aminopropionitrile and hyaluronic acid on repair of collagenase-induced injury of the rabbit Achilles tendon.
Collagenase was injected into the Achilles tendon of both hind legs of 10 clinically normal adult male New Zealand white rabbits. One month after induction of the injury, beta-aminoproprionitrile (BAPN) or hyaluronic acid (HA) was injected into the tendon core of the right hind leg of each rabbit, the left hind leg being left untreated. The treatment effects were evaluated by electron microscopy and analysis of the glycosaminoglycan (GAG) content of samples at 2 and 6 months post-treatment. At 2 months, collagen fibrils in tendons from both hind legs were relatively small in diameter, irregularly arranged, and interspersed with abundant active tenocytes as compared with those in normal tendon uninjured by collagenase. In the matrix, the amount of HA increased, but chondroitin-6-sulphate was eliminated. At 6 months, BAPN-treated tendons had small-diameter, regularly arranged collagen fibrils. HA-treated tendons, on the other hand, had large diameters, as well as regularly arranged collagen fibrils by comparison with non-treated tendon. The results suggest that HA, unlike BAPN, promoted healing.
Replacement of the tracheobronchial bifurcation by a newly developed Y-shaped artificial trachea.
We have previously reported on a straight artificial trachea developed by our group that can be applied to the cervical and thoracic trachea. In this study, a new Y-shaped artificial trachea was designed and adapted for experimental replacement of defective tracheal bifurcations in 20 dogs. The Y-shaped Marlex mesh tube was reinforced with a polypropylene spiral and coated with collagen made from porcine skin. This coating process makes the prosthesis biocompatible and airtight. Replacement of the tracheobronchial bifurcation was performed through a right thorachotomy, and omentopexy was added in all 20 dogs. Six of the 20 dogs have survived. The causes of death of the other 14 dogs were obstruction of the main bronchus (one dog), omental necrosis (three dogs), and air leakage from the prostheses and suture points (10 dogs). In all six surviving dogs, the artificial tracheas are covered with regenerated tissue and there is no evidence of stenosis or dehiscence. These results indicate that the prosthesis can be effective and safe in the long-term; however, air leakage from the prosthesis is a serious complication. Therefore, a better method is needed to make the prosthesis airtight to improve the postoperative result.
A novel surgical material made from collagen with high mechanical strength: a collagen sandwich membrane.
We have developed a novel collagen membrane with excellent mechanical properties using a new method and examined its breaking strength, microstructure, and absorption behavior in vivo. Types I and III atelopeptide collagen extracted from porcine skin by treatment with pepsin were used. One volume percent collagen hydrochloride solution, pH 3.0, was frozen in a cast, then freeze-dried and pressed. Both surfaces of the resulting membrane were coated with 2% w/v collagen hydrochloride solution, pH 3.0, and dried. This procedure was then repeated 10 times, and the membrane was finally heated in vacuo. Microstructural observation showed that the inner part of the membrane consisted of piles of thin collagen nonwoven fabric layers, whereas the coated surface consisted of an amorphous collagen layer. The breaking strength of this membrane with a thickness of 0.5 mm was 73.5 N/cm in dry conditions. The mechanical strength of the membrane was 3.4 to 10.8 times greater than that of control membranes that had not been subjected to coating procedures. The absorption of this membrane was investigated by an implantation test in rabbits. The absorption rate of the membrane in vivo was similar to that of the noncoated control material, and only minimal tissue reaction was evident. Because the mechanical properties of this membrane, made from only collagen, are adequate for suturing without reinforcement by other materials, and its absorption in vivo has so far been equal to that of collagen membranes, the membrane is potentially applicable for various surgical uses such as replacement of tissue defects.
Experimental replacement of the thoracic esophagus with a bioabsorbable collagen sponge scaffold supported by a silicone stent in dogs.
We manufactured an esophageal prosthesis made of a collagen sponge supported by an inner silicone tube. The collagen was derived from porcine skin and was crosslinked by dehydrothermal treatment. We implanted our prosthesis in nine dogs after resecting a 5 cm length of the thoracic esophagus. Intravenous hyperalimentation was performed for 4 weeks after the surgery. After 29 days, the inner silicone tube was removed endoscopically and oral feeding was restarted immediately. All nine dogs survived more than 1 month, and three of the nine dogs survived for more than 1 year. Endoscopically, the luminal surface of the regenerated esophagus was covered with a lustrous, smooth mucosa, but stenosis was observed in the midregion of the regenerated esophagus. Microscopically, no foreign material remained at the reconstructed site 1 month after surgery; the collagen sponge was absorbed and replaced by host tissue. Complete epithelization was observed within 3 months. Regeneration of the lamina muscularis mucosae, esophageal glands, and skeletal muscle were observed near the anastomoses. Our artificial esophagus holds promise for esophageal reconstruction in a clinical setting, even in the thorax.
Use of a newly developed artificial nerve conduit to assist peripheral nerve regeneration across a long gap in dogs.
There is now considerable evidence that peripheral nerves have the potential to regenerate if an appropriate microenvironment is provided. However, there are only a few reports of the successful use of artificial nerve conduits to repair major nerve defects more than 30 mm in length. In this study, we examined nerve regeneration across a long gap in the dog peroneal nerve using a novel artificial nerve conduit developed by our group. The conduit consists of a polyglycolic acid (PGA) collagen tube filled with laminin coated collagen fibers. In 12 dogs, the nerve conduit was implanted across an 80 mm gap in the left peroneal nerve. Three months after surgery, compound muscle action potentials (CMAPs) and somatosensory evoked potentials (SEPs) were detected. Evaluation of locomotor function revealed obvious limping for up to 3 months, but no marked difficulty in walking by 6 months. Microscopic observation of the regenerated nerve segment at 12 months showed numerous myelinated nerve fibers, which were smaller in diameter and enclosed in a thinner myelin sheath than normal axons. These results suggest that our artificial nerve conduit has potential usefulness in enhancing peripheral nerve regeneration, even across large gaps.
Collagen coated Y-shaped prosthesis for carinal replacement promotes regeneration of the tracheal epithelium.
Carinal reconstruction has the highest operative mortality rate in pulmonary surgery, and high tension at the anastomoses is one of the reasons. We have reported previously that a new Y-shaped artificial trachea gives acceptable short-term results. Here, we report our long-term observations and histologic findings. A Y-shaped Marlex mesh tube reinforced by a polypropylene spiral was coated with collagen, which was extracted from porcine skin, to increase the biocompatibility and airtightness of the prosthesis. Replacement of the carina was performed in 20 beagle dogs. The prosthesis was covered by the omental pedicle in all dogs. Six of the 20 dogs survived past 6 months, and 4 were in good condition when they were killed. The other 13 dogs died within 11 days of the operation. The main cause of death was air leakage from the prosthesis. Bronchoscopic examination of the surviving dogs 12 months after surgery revealed that the prosthesis was covered with regenerated tissue, and neither stenosis nor dehiscence was recognized; 15 months after implantation microscopic examination showed the growth of ciliated epithelial cells over the lumen of the prosthesis. These results suggest that our Y-shaped artificial trachea might be useful for reconstruction of the carina with tissue regrowth, although some improvement of the prosthesis is necessary.
A new tracheal bioartificial organ: evaluation of a tracheal allograft with minimal antigenicity after treatment by detergent.
The aim of this study was to reduce the antigenicity of tracheal allografts by detergent treatment. We attempted to apply these grafts to tracheal immunosuppressant-free allotransplantation. Fresh tracheal grafts were harvested from donor beagle dogs and treated with a detergent at 4 degrees C for 48 hours. By using treated grafts, we have performed tracheal immunosuppressant-free transplantation in six dogs at an intrathoracic five-ring defect. Implanted grafts were covered with an omental pedicle. In five of the six grafts, complete removal of the epithelium and mixed glands was recognized with both light microscopy and scanning electron microscopy. The appearance of the cartilage cells in the grafts was similar to those in fresh trachea. Five dogs that received detergent treated grafts survived uneventfully. The grafts had been incorporated by the host trachea without stenosis. On the one tracheal graft in which removal of the epithelium was incomplete (noted after implantation), moderate stenosis occurred 1 month after placement. These results suggest that removal of the tracheal epithelium and mixed glands can remarkably reduce tracheal antigenicity. A tracheal graft that has its epithelium and mixed glands removed can be used in tracheal immunosuppressant-free allotransplantation.
Intrathoracic esophageal replacement with a collagen sponge--silicone double layer tube: evaluation of omental-pedicle wrapping and prolonged placement of an inner stent.
In a previous study, we replaced a 5 cm gap created in the canine intrathoracic esophagus with an artificial esophagus. However, although newly formed esophageal tissue subsequently bridged the gap, mild stenosis occurred, and this seemed to be caused by inadequate regeneration of the skeletal muscle. In the present study, we evaluated whether omental pedicle wrapping (OMPx) of the prosthesis could promote tissue regeneration and whether prolonged retention of the silicone tube within the prosthesis could prevent stenosis. A gap was created in 14 dogs, and the defect was repaired by our prosthesis. OMPx was performed in 5 of the 14 dogs (OMPx group) but not in the rest (control group). The silicone tube was retained for 4 weeks in the control group and for 8 weeks in the OMPx group. All of the dogs in the control group survived for more than 3 months, except for those that were killed. Four dogs in the OMPx group died within 3 months, one caused by perforation at 7 months. Only the thin epithelial and submucosal layer regenerated in the OMPx group. OMPx is not effective for promoting tissue regeneration, and prolonged retention of the silicone tube interrupts epithelial regeneration.
A gelatin coated collagen-polyglycolic acid composite membrane as a dural substitute.
We designed a new biodegradable composite membrane for use as a dural substitute. This membrane is composed of polyglycolic acid (PGA) mesh, collagen sponge, and gelatin sponge. Collagen layers are attached on both sides of the PGA mesh. One side of the membrane is coated with freeze-dried gelatin to prevent tissue adhesion. We examined the mechanical properties of the membrane and evaluated its efficacy in vivo by implanting it into dogs. When the mechanical properties of the membrane were measured under wet conditions, tensile strength and resistance against cutting by a suture were approximately 20 N/cm and 13 N, respectively, which are adequate for a surgical material. In the in vivo experiment, our dural substitute was implanted into six adult beagle dogs to repair a 25 x 15 mm defect in the dura mater. Two dogs each were killed at 2 and 4 months after implantation and two were observed over 6 months. At 4 months after implantation, the implanted dural substitute was almost absorbed and a fibrous membrane resembling native host dura had regenerated at the site. No foreign body reaction or significant adhesion to the cerebral cortex was observed. These results indicate the clinical potential of our novel dural substitute.
Yolk sac tumor of the ovary: radiologic-pathologic correlation in four cases.
We report the radiologic and pathologic features of yolk sac tumor (endodermal sinus tumor) of the ovary in four patients. Yolk sac tumors were shown as well-enhancing solid tumors on both CT and MR studies and were associated with prominent signal voids on MRI. A hypervascular nature was confirmed on microscopic studies. Areas of hemorrhage were another common characteristic. These imaging findings seem to have an important implication for the diagnosis of this tumor.