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S Kan

Publications and source records attributed to S Kan.

At least 19 recordsLinked to original sources
PubMed2001

Operational tolerance induced by pretreatment with donor dendritic cells under blockade of CD40 pathway.

BACKGROUND: Dendritic cells can mount immune response as competent antigen presenting cells. Recently, it has been reported that immature dendritic cells induce prolongation of allograft survival. However, the ability of mature dendritic cells to induce operational tolerance is unclear. Therefore, in this study, we examined the ability of splenic mature dendritic cells to induce operational tolerance to fully allogeneic antigens using mouse heterotopic heart transplantation model. METHODS: CBA (H2k) mice received i.v. injections with donor splenic dendritic cells or B cells in the absence or presence of monoclonal antibody (mAb) specific for CD40 ligand or CD80/CD86 2 weeks before transplantation of a C57BL/10 (H2b) heart. RESULTS: When donor dendritic cells were injected i.v. 2 weeks before transplantation, rejection response was accelerated compared with that of naive mice [median survival time (MST) = 7 and 8 days, respectively]. However, when CD40 pathway was blocked by anti-CD40 ligand mAb, i.v. injection of donor dendritic cells but not B cells induced indefinite graft survival (MST >100 and 20 days, respectively). Mice treated with anti-CD40 ligand mAb alone rejected their grafts with a MST of 18 days. Intravenous injection of donor dendritic cells and B cells in combination with anti-CD80/CD86 mAbs was less effective to induce graft prolongation (MST = 9.5 and 13 days, respectively). CONCLUSIONS: Therefore, under blockade of CD40 pathway, mature dendritic cells were tolerogens in vivo independent of CD80/86 pathways.

Adoptive Transfer↗
PubMed2001

Endoscopic total parathyroidectomy by the anterior chest approach for renal hyperparathyroidism.

BACKGROUND: During the past 3 years, minimally invasive procedures have been adopted for the surgical treatment of primary hyperparathyroidism, and we have tried to perform endoscopic total parathyroidectomy for renal hyperparathyroidism. METHODS: Five 5-mm trocars were inserted through the skin of the anterior chest under a general anesthesia. Carbon dioxide was then insufflated up to 4 mmHg, and the endoscopic surgery was performed. RESULTS: Endoscopic procedure was successfully performed in five patients. The mean duration of total parathyroidectomies was 236 min. No evidence of injury to the recurrent laryngeal nerve was observed in any cases. At follow-up, the serum calcium and parathyroid hormone levels had returned to within the normal range in all patients. Postoperative cosmetic status was excellent. CONCLUSION: We believe that endoscopic total parathyroidectomy by the anterior chest approach will find a role in the treatment of renal hyperparathyroidism.

Female↗
PubMed2001

Endoscopic thyroidectomy and parathyroidectomy by the axillary approach. A preliminary report.

BACKGROUND: The use of endoscopic procedures leads to a reduction in the size of the surgical scar, making it more inconspicuous. In this paper, we evaluated the merits and limits of endoscopic neck surgery. METHODS: Between August 1999 and July 2000, 102 patients underwent neck surgery in our department for thyroid or parathyroid disease. Twenty-eight of them were treated by the axillary. A 12-mm and two 5-mm trocars were inserted through the skin of the axilla. Carbon dioxide was then insufflated up to 4 mmHg, and the endoscopic surgery was performed. RESULTS: Endoscopic procedures were performed successfully in 26 cases (19 thyroidectomies and seven parathyroidectomies). There were two conversions to open procedures. The mean operating times for the thyroidectomies and parathyroidectomies were 212 and 171 min, respectively. No evidence of injury to the recurrent laryngeal nerve was observed in any of the cases. The postoperative cosmetic status of the patients was excellent. CONCLUSION: We believe that endoscopic thyroidectomy and parathyroidectomy by the axillary approach will find a role in the treatment of endocrine diseases in the neck.

Adenocarcinoma, Follicular↗
PubMed2001

Superficialization of hemodialysis access using a video-assisted procedure.

Brachiocephalic fistula is one of the main options to gain blood access for hemodialysis. Although the fistula is easy to establish, puncture becomes increasingly difficult because the cephalic vein runs deep and fibrous tissue is being continually deposited over the cephalic vein. Although superficialization-i.e., the removal of fibrous tissue along the basilic vein-has been performed with conventional surgery, the long incision along the cephalic vein induces the buildup of hard fibrous tissue so that puncture may remain difficult even after the operation. To avoid this problem, we tried superficialization of hemodialysis access using a video-assisted procedure and obtained a good result.

Arm↗
PubMed2001

Endoscopic thyroidectomy by the axillary approach.

Neck surgery has recently become one of the newest fields for the application of endoscopic surgery because the resultant scar is small and inconspicuous. Still, some patients feel even a small scar on the neck is not cosmetically acceptable. We therefore have developed a new technique of endoscopic thyroidectomy by the axillary approach that leaves no scar on the neck at all. When this method is used, the small scar in the axilla is completely covered by the patient's arm in a natural manner. The cosmetic result is excellent, and sensory loss in the neck is negligible because the area of surgical dissection is small. We believe that endoscopic thyroid surgery by the axillary approach will find a role in the treatment of thyroid disease.

Axilla↗
PubMed2001

Laparoscopic partial or cortical-sparing adrenalectomy by dividing the adrenal central vein.

BACKGROUND: We perform laparoscopic partial adrenalectomy without sectioning the adrenal central vein has been described because it is important to preserve this vein in the remnant adrenal gland in order to maintain its function. In this article, we describe our technique for laparoscopic partial or cortical-sparing adrenalectomy by dividing the adrenal central vein. METHODS: The procedures were performed in four patients with aldosterone-producing adenomas (APA) and two patients with pheochromocytomas. RESULTS: There were no postoperative complications. At follow-up, adrenal 131I-adosterol scintigrams showed that remnant adrenal function had been preserved in all cases. CONCLUSION: Since the vascular bed adjacent to the remnant adrenal gland is integral to the preservation of its function, it is important to perform procedures that do not separate the remnant adrenal gland from the retroperitonium space. Because the operative field is clearly visualized on the high-magnification video monitor, this delicate procedure can be performed with a high degree of accuracy via the laparoscopic approach. We consider this operative technique to be useful for selected cases.

Adrenal Cortex↗
PubMed2001

Transient seizure activity demonstrated by Tc-99m HMPAO SPECT and diffusion-weighted MR imaging.

Cerebral perfusion single photon emission computed tomography (SPECT) has been used to confirm the localization of the epileptic focus and the evaluation of seizure. Recently, diffusion-weighted MR imaging (DWI) has been recognized for evaluation of seizure activity. We describe a case of transient seizure activity demonstrated by Tc-99m HMPAO SPECT and DWI. This patient was a 61-year-old woman with a 10-month history of right middle cerebral artery (MCA) infarction who had a generalized seizure during MRI. DWI immediately after seizure showed transient hyperintensity in the right frontal gray matter and the white matter, and these apparent diffusion coefficients (ADC) were transiently decreased. This transient hyperintensity on DWI corresponded to transient hyperperfusion identifying the epileptic focus on interictal Tc-99m HMPAO SPECT. Transient sustained seizure activity might cause these changes on DWI and SPECT. It was considered that interictal Tc-99m HMPAO SPECT showed the delayed hyperperfusion caused by excitatory neuronal overaction and DWI showed cytotoxic edema seizure-induced by energy failure of the membrane-bound Na/K-ATPase pump.

Cerebral Infarction↗
PubMed2001

Bilateral crossed cerebello-cerebral diaschisis and mutism after surgery for cerebellar medulloblastoma.

A 7-year-old boy developed mutism after surgery for cerebellar medulloblastoma. Postoperative magnetic resonance imaging (MRI) showed atrophy of the cerebellar vermis and both cerebellar hemispheres, predominantly on the right side. Single photon emission computed tomography (SPECT) with technetium-99m-ethyl cysteinate dimer (Tc-99m ECD) revealed decreased cerebral blood flow (CBF) in the bilateral thalami, bilateral medial frontal lobes, and left temporal lobe in addition to the cerebellar vermis and both cerebellar hemispheres when mutism was manifest, indicating the existence of bilateral crossed cerebello-cerebral diaschisis (BCCCD). Circulatory disturbance in both cerebellar hemispheres secondary to tumor resection probably caused BCCCD in both cerebral hemispheres, predominantly in the left, via the dentatothalamocortical pathway (DTCP). With recovery of his mutism, CBF increased in the right thalamus, bilateral medial frontal lobes and left temporal lobe. Thus BCCCD was improved, with only a slight decrease in CBF still persisting in the left thalamus. The mechanism of mutism may have involved damage to the cerebellar vermis (the site of incision at operation), the left dentate nucleus (heavily infiltrated by the tumor) and the right dentate nucleus of the cerebellum (affected by circulatory disturbance secondary to acute postoperative edema). The SPECT findings suggested that mutism was associated with BCCCD-induced cerebral circulatory and metabolic hypofunction in the supplementary motor area mediated via the DTCP.

Cerebellar Neoplasms↗
PubMed2001

Localization of post-traumatic trochlear nerve palsy associated with hemorrhage at the subarachnoid space by magnetic resonance imaging.

PURPOSE: To report evaluation of traumatic trochlear nerve palsy using head magnetic resonance imaging. DESIGN: Observational case reports. METHODS: We examined two cases involving trochlear nerve palsy after closed head injury. RESULTS: Using a fluid attenuated inversion recovery pulse sequence, MRI showed a high-intensity lesion consistent with subarachnoid hemorrhage at the trochlear nerve area in the ambient cisterns. CONCLUSION: An impact force directed toward the tentorium can be a mechanism of injury in some post-traumatic trochlear nerve palsies. Fluid attenuated inversion recovery pulse sequence is a sensitive method for detection of abnormalities in cases associated with head injury.

Adolescent↗
PubMed2001

Importance of thymus to maintain operational tolerance to fully allogeneic cardiac grafts.

BACKGROUND: The effectiveness of donor-specific blood transfusion (DST) before transplantation has been established. Anti-CD4 monoclonal antibody (anti-CD4) augments the ability of DST to induce indefinite prolongation. Therefore, we investigated the importance of thymus to maintain the unresponsiveness to alloantigens. METHODS: CBA mice were pretreated with 0.25 mL of DST or two doses of anti-CD4 before transplantation of a C57BL/10 heart. Some mice were thymectomized. RESULTS: Naive CBA mice rejected C57BL/10 grafts acutely with a median survival time of 7 days. When mice were pretreated with anti-CD4 plus DST 4 weeks before transplantation, all grafts survived indefinitely (>100 days), whereas mice treated with DST alone or anti-CD4 alone rejected acutely (median survival time, 7 and 12 days, respectively). To investigate the importance of thymus, mice pretreated with anti-CD4 plus DST 4 weeks before transplantation were thymectomized or underwent a sham operation 1 day before grafting. Mice with the sham operation accepted grafts indefinitely, whereas thymectomized mice rejected the majority of the grafts (median survival time, 20 days). CONCLUSIONS: The thymus is important in maintaining the operational tolerance induced by anti-CD4 plus DST 4 weeks before grafting.

Adoptive Transfer↗
PubMed2001

Clinical significance of tissue blood flow during esophagectomy by laser Doppler flowmetry.

OBJECTIVES: We sought to investigate the effect of tissue blood flow on the incidence of anastomotic leakage during esophagectomy. METHODS: Reconstruction was done with a gastric tube, and all cases involved cervical anastomosis. Tissue blood flow of 43 patients was measured with a laser Doppler flowmeter before emplacement and after anastomosis during surgical intervention. The reconstruction route and tissue blood flow before emplacement and that after anastomosis were analyzed as possible factors influencing anastomotic leakage. RESULTS: Tissue blood flow after anastomosis with leakage was 9.1 +/- 2.0 mL/min per 100 g, and that without leakage was 13.7 +/- 2.9 mL/min per 100 g. Tissue blood flow with leakage was significantly lower than that without leakage (P <.01, unpaired t test). Twenty-one patients had tissue blood flow after anastomosis of greater than 13 mL/min per 100 g, and none of them had leakage, whereas 5 patients had blood flow of less than 10 mL/min per 100 g, and all 5 had leakage. CONCLUSION: Tissue blood flow can be an important and useful indicator of the presence of current anastomotic leakage. Low tissue blood flow after anastomosis may mediate for appropriate surgical or pharmacologic interventions to detect, localize, and counteract leakage.

Anastomosis, Surgical↗
PubMed2001

Tight Sylvian cisterns associated with hyperdense areas mimicking subarachnoid hemorrhage on computed tomography--four case reports.

Four patients with supratentorial mass lesions (two chronic subdural hematomas, one acute epidural hematoma, and one acute subdural hematoma) showed hyperdense sylvian cisterns on computed tomography (CT). Association of subarachnoid hemorrhage was suspected initially, but was excluded by intraoperative observation or postoperative lumbar puncture. CT showed disappearance of the hyperdense areas just after evacuation of the mass lesions. The hyperdense areas are probably a result of the partial volume phenomenon or concentrations of calcium deposits rather than abnormally high hematocrit levels, which were not found in these patients.

Accidental Falls↗
PubMed2001

Rupture of pial arteriovenous malformation associated with early thrombosis of the draining system following stereotactic radiosurgery--case report.

A 50-year-old man was treated with stereotactic gamma knife radiosurgery for an incidentally detected small callosal arteriovenous malformation (AVM) with stenosis of the main draining pathway. He suffered two episodes of intraventricular hemorrhage at 4 and 14 weeks after the radiosurgery. Radiological studies demonstrated that the anterior portion of the draining system including a varix, which had been irradiated, was thrombosed before the obliteration of arteriovenous shunts. Stereotactic radiosurgery is an accepted treatment for selected small and medium AVMs, but this procedure may increase the risk of bleeding. Early occlusion of a part of the draining pathway after stereotactic radiosurgery might have induced AVM rupture. An impaired venous outlet, either consisting of one draining vein or with stenosis, present before treatment may be develop thrombosis in response to high-dose irradiation.

Aneurysm, Ruptured↗
PubMed2001

Coil embolization for the treatment of ruptured dissecting vertebral aneurysms.

BACKGROUND AND PURPOSE: Proximal occlusion of the parent artery has been widely used for treatment of vertebral dissecting ruptured aneurysms, but this does not always completely prevent rerupture. We retrospectively studied 24 consecutive patients for clinical characteristics and/or for efficacy of occlusion with detachable coils at the site of dissection. METHODS: During a 45-month period, 24 of 242 patients with aneurysms associated with subarachnoid hemorrhage had dissecting vertebral aneurysms identified at angiography. Eighteen of the 24 patients were treated with platinum coil occlusion at the affected site as early as possible after diagnosis, two patients were treated conservatively, and four others were not eligible for treatment owing to intractable elevation of intracerebral pressure and severe brain stem dysfunction. RESULTS: The rate of aneurysmal rupture in the posterior fossa was high, at 56 (23%) of the 242 aneurysms, including 24 (10%) vertebral dissecting aneurysms. Subsequent rupture occurred in 14 (58%) of the patients, all within 24 hours after the first attack and three during transportation to the hospital. In all 18 patients, coil embolization at the affected site was successful, with no complications. Radiologic findings showed complete occlusion of the dissection site and patency of the unaffected artery (mean follow-up, 9 months). Among the six patients who did not undergo embolization, only one survived with a good outcome, the others died of repeat hemorrhage. CONCLUSION: A high rate of vertebral artery dissecting aneurysms may be expected in patients with subarachnoid hemorrhage, especially in those with early repeat hemorrhage. Detachable platinum coil embolization may be more effective than proximal occlusion for treatment of ruptured vertebral dissecting aneurysms because of immediate cessation of blood flow to the dissection site; however, in patients with bilateral dissections or hypoplastic contralateral vertebral arteries, prior bypass surgery orstent placement to preserve the artery will be needed.

Adult↗