Gastrointestinal AA Amyloidosis following Recurrent SARS-CoV-2 Infection: A Case Report

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been associated with the overproduction of serum amyloid A protein, resulting in systemic AA amyloidosis. In this report, we describe a case of gastrointestinal (GI) AA amyloidosis following SARS-CoV-2 infection. A 75-year-old male presented to the emergency department with upper abdominal pain 6 weeks post kidney transplantation. He had a history of SARS-CoV-2 infection 4 weeks prior. On day 7 of hospitalization, while receiving conservative management, the patient developed symptoms of cough and fever, leading to a diagnosis of SARS-CoV-2 reinfection. The patient’s abdominal pain persisted, and hematochezia developed on day 30 of hospitalization. Esophagogastroduodenoscopy and colonoscopy revealed multiple ulcers in the stomach and colon, with histologic findings revealing the presence of amyloid A. The patient was managed conservatively and was also given remdesivir for the SARS-CoV-2 infection. His clinical symptoms subsequently improved, and endoscopic findings demonstrated improvement in multiple gastric ulcers. GI amyloidosis may be a subacute complication following SARS-CoV-2 infection in immunocompromised patients.

Antithrombotic therapy has no beneficial effect in conservative treatment of spontaneous isolated superior mesenteric arterial dissection

Purpose@#Initial conservative treatment with selective endovascular or surgical intervention has shown successful outcomes in the treatment of spontaneous isolated superior mesenteric artery dissection (SISMAD). However, the benefits of antithrombotic therapy as a part of conservative treatment have not been clarified. This study aimed to investigate the clinical course of SISMAD patients and determine differences in clinical outcomes between the antithrombotic and noantithrombotic groups. @*Methods@#We retrospectively reviewed 79 cases of SISMAD that were treated conservatively from January 2004 to December 2019 at Chonnam National University Hospital. Clinical outcomes, including the length of hospital stay, pain resolution time, image remodeling, and maximal remodeling time, were compared between the antithrombotic and noantithrombotic groups. @*Results@#There were 30 patients in the no-antithrombotic group and 49 patients in the antithrombotic group. There was no significant difference in clinical characteristics between the 2 groups, except for dyslipidemia (P = 0.011). The follow-up period (32.6 months vs. 14.6 months, P = 0.009) and imaging follow-up period (31.6 months vs. 13.9 months, P = 0.011) were longer in the antithrombotic group than in the no-antithrombotic group. The length of hospital stay (5.1 days vs. 7.7 days, P = 0.002) was significantly shorter in the no-antithrombotic group than in the antithrombotic group because patients in the antithrombotic group required longer hospitalization for warfarin titration. @*Conclusion@#In patients with SISMAD, conservative treatment without antithrombotic therapy may have clinical benefits such as decreased length of hospital stay compared with conservative treatment with antithrombotic therapy.

Colon perforation due to embolization coil for internal iliac aneurysm

Coil migration is an extremely rare but hazardous complication of aneurysmal coil embolization. Only 1 case report has described coil migration following endovascular exclusion to gastrointestinal (GI) tract. We report the experience of a case of colon penetration caused by embolization coil placed for internal iliac aneurysm. A 66-year-old man visited the Emergency Department for hematochezia that had persisted for 3 months. Stent insertion and coil embolization of left internal iliac artery aneurysm had been performed on the patient 18 months ago. Colonoscopy was performed. It suggested penetration of sigmoid colon by embolization coil and diverticulum. Angiography revealed extravasation of contrast media at left internal iliac artery. Covered stent deployment was done in the left internal iliac artery. One week after the stent insertion, the patient underwent anterior resection, aneurysm resection, and coil removal. The patient recovered without complications. He was discharged at 2 weeks after the operation.

Vascular Complications Related to Posterior Lumbar Disc Surgery

PURPOSE: To evaluate patients who underwent surgical or endovascular treatment after vascular injury related to posterior lumbar disc surgery. MATERIALS AND METHODS: We retrospectively reviewed seven cases of vascular injuries (four lacerations, one arteriovenous fistula [AVF], and two pseudoaneurysms) related to lumbar disc surgery by a posterior approach from January 1997 to December 2016 at Chonnam National University Hospital. Information of patient characteristics, diagnosis, treatment strategies, and outcomes were analyzed. RESULTS: Five out of seven cases were inhospital cases. In three laceration cases, each patient instantly became hypotensive and a life-threatening arterial injury was suspected. Therefore, the patient was immediately turned to the supine position and surgical repair was performed. The patients with pseudoaneurysm and AVF were treated by endovascular intervention. Remaining two were referred cases under the impression of vascular injuries. One laceration case of them was in preshock condition, and the left common iliac artery was surgically repaired. The other referred patient showed pseudoaneurysm which was treated with stent graft insertion. There was no surgery or endovascular intervention related death and none of the patients suffered any sequela related to vascular injury. CONCLUSION: Vascular injury associated with posterior lumbar disc surgery is not common, but can be fatal. Early recognition, diagnosis, and prompt treatment are essential to prevent fatal outcomes. Recently, endovascular intervention is increasingly and preferably used because of its low morbidity and mortality. However surgery is still the best option for the patients with unstable vital sign and endovascular approach can be applied to stable patients.

Anatomical Features and Early Outcomes of Endovascular Repair of Abdominal Aortic Aneurysm from a Korean Multicenter Registry

PURPOSE: To introduce a nation-based endovascular aneurysm repair (EVAR) registry in South Korea and to analyze the anatomical features and early clinical outcomes of abdominal aortic aneurysms (AAA) in patients who underwent EVAR. MATERIALS AND METHODS: The Korean EVAR registry (KER) was a template-based online registry developed and established in 2009. The KER recruited 389 patients who underwent EVAR from 13 medical centers in South Korea from January 2010 to June 2010. We retrospectively reviewed the anatomic features and 30-day clinical outcomes. RESULTS: Initial deployment without open conversion was achieved in all cases and procedure-related 30-day mortality rate was 1.9%. Anatomic features showed the following variables: proximal aortic neck angle 48.8+/-25.7degrees (mean+/-standard deviation), vertical neck length 35.0+/-17.2 mm, aneurysmal sac diameter 57.2+/-14.2 mm, common iliac artery (CIA) involvement in 218 (56.3%) patients, and median right CIA length 34.9 mm. Two hundred and nineteen (56.3%) patients showed neck calcification, 98 patients (25.2%) had neck thrombus, and the inferior mesenteric arteries of 91 patients (23.4%) were occluded. CONCLUSION: Anatomical features of AAA in patients from the KER were characterized as having angulated proximal neck, tortuous iliac artery, and a higher rate of CIA involvement. Long-term follow-up and ongoing studies are required.

Changes in suprarenal and infrarenal aortic angles after endovascular aneurysm repair

PURPOSE: We investigated whether suprarenal and infrarenal aortic angles change after the endovascular aneurysm repair (EVAR) procedure and during follow-up, and investigated the correlation between infrarenal aortic angle after EVAR and type Ia endoleaks. METHODS: Data collected on 70 EVAR procedures for a fusiform infrarenal aortic aneurysm performed between May 2006 and December 2012 were supplemented with a retrospective review of charts and radiographs. RESULTS: The greater the preoperative infrarenal aortic angle, the greater the suprarenal aortic angle (r = 0.72, P < 0.001). The infrarenal aortic angle decreased after the EVAR procedure and continued to decrease slowly thereafter (all P < 0.001). Suprarenal aortic angle decreased immediately after the EVAR procedure and continued to decrease during the first month (P < 0.001). No differences in angulation were observed based on stent graft type. Type Ia endoleaks occurred with significantly greater incidence in patients with a larger post EVAR infrarenal angle (P = 0.037). CONCLUSION: The infrarenal aortic angle decreased significantly immediately after the EVAR procedure and continued to decrease slowly thereafter. Suprarenal aortic angle decreased immediately after the EVAR procedure and continued to decrease during the first month. We found a correlation between infrarenal and suprarenal aortic angle. Type Ia endoleaks occurred with greater incidence in patients with a larger infrarenal angle immediately after EVAR.

Alteration of Ankle-Brachial Index after Kidney Transplantation / 대한이식학회지

BACKGROUND: A steno-occlusive disease of the iliac artery can mimic renal vascular hypertension, and is an important cause of renal dysfunction in renal transplant recipients. We assessed the alternation of postanastomotic arterial blood flow of lower extremities by ankle-brachila index (ABI). METHODS: We analyzed 50 patients who underwent kidney transplantation between March, 2010 and November, 2012 at Chonnam National University Hospital. This study was performed prospectively and case selection by renal transplantation patients who got first operation on right iliac fossa. All operational procedures were end to side anastomosis of the external iliac artery to the renal artery. We measured and compared the preoperative and postoperative (1 week, 6 months, 1 year) ABI. We analyzed the diameter of the recipient external iliac artery and renal artery of the transplanted kidney. RESULTS: Among 50 patients, 34 were male (68%) and 16 were female (32%). The mean age of recipients was 44.37+/-11.42 years. The mean preoperative ABI at the right lower extremity was 1.17+/-0.11, postoperative 1 week, 6 months, and 1 year was 1.14+/-0.10, 1.15+/-0.11, 1.17+/-0.15, respectively. Alternation of preoperative ABI and postoperative 1 week, 6 months, and 1 year was P=0.331, P=0.864, and P=0.992, respectively. CONCLUSIONS: Alternation of ABI on the ipsilateral lower extremity was not significant in renal transplanted recipients. We recommend a long-term study with more cases.

Clinical Analysis of Foreign Bodies in Gastrointestinal Tract in Children / 소아외과

Foreign body ingestion is a common problem among paediatric populations. Most of the ingested foreign bodies spontaneously pass through the gastrointestinal tract, but approximately less then 10% of them remain without being discharged, and trigger complications. Therefore, proper evaluation and treatment according to the situation is required. In this study, clinical progress and complications were analyzed according to the clinical features and treatment in children who ingested foreign bodies. Among pediatric patients under 18 who were admitted to Chonnam National University Hospital after ingesting foreign bodies between January 2008 to June 2012, only the patients who had their foreign body in the gastrointestinal tract were included in this study. Based on medical records, age, type of foreign body, time spent till admission, and whether the endoscopy was done or not, complication were researched retrospectively. According to symptoms and plain abdomen X-ray findings, treatment was chosen and conducted among endoscopy, observation and emergency operation. Among 273 patients, 9 (3.3%) of them had surgical removal. Seven (2.6%) of them had an emergency operation on the day of admission, and the rest 2 (0.7%) had operation during observation. Removal through initial endoscopic approach was tried in 157 (57.5%) patients. Eleven (70.8%) of them had their foreign body removed at the initial trial, and 5 (4.9%) of them at the second trial. Among 109, who were on observation status, 9 (8.3%) of them needed endoscopic removal, and 2 (1.8%) of them suffered from surgical removal. It is thought to be better to approach slowly considering the type, size and symptoms in foreign body ingestion of pediatric patients, rather than immediate and invasive removal.

Factors Affecting the Endoleaks of Endovascular Aneurysm Repair in Infrarenal Abdominal Aortic Aneurysms / 대한혈관외과학회지

PURPOSE: The purpose of this study is to evaluate the factors affecting the endoleaks of endovascular aneurysm repairs in infrarenal abdominal aortic aneurysms. METHODS: On a retrospective basis, we analyzed 122 patients, who underwent endovascular aneurysm repair (EVAR) for infrarenal abdominal aortic aneurysm between March, 2006 and June, 2011. According to the endoleak, the patients were divided into 2 groups: endoleak group and non-endoleak group. We compared the following variables between the 2 groups: patient clinical characteristics (age, gender, body mass index, history of smoking, hypertension, diabetes mellitus, and coronary artery disease) and anatomical features of the aneurysms. RESULTS: A total of 111 male and 11 female patients were included. Fifty-two patients showed endoleak (42.6%) during follow-up periods (median: 4.6 years). There was no significant difference between endoleak and non-endoleak group according to patient's clinical characteristics and used devices. However, there were significant differences between two groups according to the anatomical features of the aneurysm, such as the morphology, size of the aneurysm, and the size and angle of the neck of the aneurysm. CONCLUSION: Endoleak indicated high frequency when the aneurysm size is large, and when the neck aneurysm is large, with the neck angle being more than 60 degrees. Thus, patients with more than one of the above three characteristics may need more attentive and cautious procedures as well as a closer follow-up.

MicroRNA profiling of tacrolimus-stimulated Jurkat human T lympocytes / 대한외과학회지

PURPOSE: This study investigated the Jurkat T cell line expresses cytotoxicity when treated with different concentrations of FK506, and analyzed the expression pattern of microRNA when stimulated by FK506 using the microRNAs microarray, as well as the expression pattern of a gene that is related to the differentiation, activation and proliferation of T cells after being affected by the change of microRNAs. METHODS: To investigate the effects of FK506 on microRNA expression, we purified total RNA of Jurkat cells treated with 20 microM FK506 for 72 hours and used to analyze microRNA profiling by using Agilent's chip. RESULTS: These results demonstrated that treatment with FK506 markedly induced the down-regulation of 20 microRNAs as well as the up-regulation of 20 microRNAs in a time-dependent manner. The genes that down-regulated by FK506 include let-7a*, miR-20a*, and miR-487a. Otherwise miR-202, miR-485-5p, and miR-518c* are gradually up-regulated in expression. Sanger Institute and DAVIDs bioinformatics indicated that microRNAs regulated the several transcriptomes including nuclear factor of activated T cell-related, T cell receptor/interleukin-2 signaling, and Ca(2+)-calmodulin-dependent phosphatase calcineurin pathways. CONCLUSION: As a result of treating FK506 to a Jurkat cell line and running the microRNA microarray, it was found that FK506 not only took part in the suppression of T cell proliferation/activation by inhibiting calcineurin in Jurkat apoptosis, but also affected the microRNAs that are involved in the regulation of various signal transduction pathways.

Evaluation of the Korean Network for Organ Sharing Expanded Donor Criteria in Deceased Donor Renal Transplantation / 대한이식학회지

BACKGROUND: This study was conducted in order to evaluate the propriety of expanded donor criteria in Korea and to identify the preoperative factors influencing allograft survival and function. METHODS: We studied 404 patients who received deceased renal transplants from five transplantation centers of 2, 3 territory from 2000 to 2010. Differences in 1-year graft function, delayed graft function (DGF) rate, and graft survival rate between the standard criteria donor (SCD) and expanded criteria donor (ECD) were compared retrospectively. The preoperative factors influencing graft function and graft survival were analysed. RESULTS: SCD showed significantly better 1-year graft function than ECD (P=0.011). No differences in 1-year acute rejection rate were observed between SCD (13.2%) and ECD (16.9%) (P=0.449). Significantly higher DGF rate was observed for ECD (25.4%) than for SCD (14.1%) (P=0.022). Graft type had no significant influence on 5-year graft survival (SCD 94.5% vs. ECD 93.7%) (P =0.835). Advanced donor age (P=0.001), donor hypertension history (P=0.047), high serum creatinine (P=0.002), and cerebral infarction as cause of death (P=0.004) had a negative influence on 1-year allograft function. Significantly low graft survival was observed for advanced donor age (P =0.002). CONCLUSIONS: Graft function, DGF rates of ECD were poorer than those of SCD. Graft survival rate of ECD was comparable to that of SCD kidney. Korean Network for Organ Sharing expanded criteria may underestimate the organ quality of deceased kidney and modification may be needed in order to expand the potential donor pool through nationwide study.

Clinical Experiences of Transarterial Embolization after Abdominal Surgery in Trauma Patients / 대한혈관외과학회지

PURPOSE: Transarterial embolization has been known as an effective nonsurgical treatment for selected patients with intraabdominal hemorrhage. This study was conducted to evaluate the clinical outcomes of transarterial embolization after emergency operation in the blunt abdominal trauma patients with hemoperitoneum. METHODS: Between January 2004 and December 2008, a total of 13 consecutive blunt abdominal trauma patients with intraabdominal hemorrhage who received transarterial embolization after abdominal surgery were included. The characteristics, procedures, and the clinical outcomes of patients were analyzed, retrospectively. RESULTS: There were 6 males and 7 females. Age ranged between 21 and 77 years (mean 42.3 years). The most common injured organ was the liver (10 patients, 76.9%), and the most common embolized artery was hepatic artery (8 patients, 61.5%). Transarterial embolizations were intended to control the continued bleeding (9 patients, 69.2%), delayed bleeding (3 patients), and arteriovenous fistula (1 patient). Further, technical success was achieved in all 13 patients. One of 13 patients died of multiorgan failure. No procedure-related complications were observed. CONCLUSION: Angiography has a high detection rate of bleeding sites in patients with intraabdominal hemorrhage after blunt abdominal trauma. Transarterial embolization is considered as an effective and safe method in the management of intraabdominal hemorrhage after abdominal surgery in trauma patients.

Mycophenolic acid mediated mitochondrial membrane potential transition change lead to T lymphocyte apoptosis / 대한외과학회지

PURPOSE: This study demonstrated that apoptosis induced by mycophenolic acid (MPA) is mediated by mitochondrial membrane potential transition (MPT) changes in Jurkat cells. METHODS: Cell viability and MPT changes were measured by flow cytometry. Western blotting was performed to evaluate the expression of Bcl-2 family proteins, Bid, truncated Bid (tBid), cytochrome c, voltage dependent anion channel (VDAC), poly ADP-ribose polymerase (PARP), and protein kinase C-delta (PKC-delta). The catalytic activity of caspase-9 and -3 was also measured. RESULTS: Cell viability was decreased in time- and dose-dependent manners. Bcl-2 protein expression was decreased, but Bax protein expression was identified. A decreased Bcl-XL /Bcl-XS ratio was also noted. The expression of tBid protein also increased in a time-dependent manner in Jurkat cells treated with MPA. While normal MPT appeared as orange fluorescence, abnormal MPT corresponded to green fluorescence. Green fluorescence increased as orange decreased in the MPA-treated cells. Significantly increased concentrations of MPA induced the release of cytosolic cytochrome c. MPA also augmented the catalytic activity of caspase-9 and caspase-3 in Jurkat cells. Our findings demonstrated that MPA-induced apoptosis is mediated by MPT changes accompanied by decreased Bcl-XL expression and the appearance of tBid protein. The release of cytosolic cytochrome c from mitochondria and increased catalytic activity of caspase-9 and caspase-3 were observed in MPA-treated Jurkat cells. CONCLUSION: These results suggest that mitochondrial dysfunction caused by MPA induces human T lymphocyte apoptosis.

Peliosis Hepatis Cured with Anti-tuberculosis Medication in a Hemodialysis Patient / 대한신장학회지

Peliosis hepatis is an uncommon condition of blood-filled cystic cavities in the liver. Although it is difficult to distinguish this condition from hepatic malignancy or abscess in computed tomography (CT), differential diagnosis is important because it doesn't need further evaluation or treatment such as liver biopsy or surgery. We report a case of peliosis hepatis in a patient with active pulmonary tuberculosis in hemodialysis patient. A 39-year-old man receiving hemodialysis for 3 months was admitted because of fever. Chest computed tomography (CT) showed multiple necrotic lymphadenopathies and nodular lesion in right upper lobe of the lung suggesting active pulmonary tuberculosis. Three low attenuated lesions were shown in both hepatic lobes in abdominal CT. Liver biopsy was performed. The histopathologic diagnosis of peliosis hepatis in the liver was made by a blood-filled space with fibrin and hemorrhage. After anti-tuberculosis therapy, hepatic low attenuated lesions disappeared.

Incarcerated Obturator Hernia: The Need of Herniorrhaphy in Self-reduced Obturator Hernia

An obturator hernia is an exceptionally rare form of hernia. It occurs mostly in elderly, thin, multiparous, and emaciated women. Correct diagnosis and treatment is important because delayed treatment can lead to a higher mortality rate. Recently, we experienced two cases of mechanical small bowel obstruction due to incarcerated obturator hernia. One of these patients was an 83-year-old woman who was diagnosed with left incarcerated obturator hernia by computed tomography (CT). The patient's symptom disappeared abruptly. A recheck CT scan revealed self-reduction of the obturator hernia, and the patient refused operation. Two weeks later, the patient was presented again to the emergency clinic with incarcerated small bowel in the left obturator hernia, which was seen on CT. The other patient was a 79-year-old woman who had a 2-day history of abdominal pain. She was diagnosed with a right obturator hernia by CT. Both patients were treated without bowel resection.

Mycophenolic Acid Induced Apoptosis in Human Jurkat Cells viathe Generation of Reactive Oxygen Species

PURPOSE: Mycophenolic acid (MPA) is the active agent of mycophenolate mofetil (MMF), which is an immunosuppressive drug. MPA is a selective inhibitor of inosine monophosphate dehydrogenase. The aim of this study was for demonstrate that mycophenolic acid induces apoptosis in human Jurkat cells via the generation of reactive oxygen species (ROS). METHODS: The cells were cultured in the presence or absence of MPA. Flow cytometric analysis was performed after propidium iodide staining. Western blotting for caspase 3, Bcl-2 and Bax proteins was also performed. RESULTS: MPA decreased the viability of Jurkat cells in a dose- and time-dependent manner. The MPA induced apoptotic cell death displayed nuclear fragmentation and sub G0/G1 phase arrest in the Jurkat cells. The expression of caspase-3 proteases in the MPA treated-Jurkat cells increased in a time-dependent manner. Treatment with MPA resulted in increased ROS generation in the Jurkat cells. There was a decreased expression of Bcl-2 and an increased expression of Bax protein in the MPA treated Jurkat cells. CONCLUSION: This result suggests that MPA-induced cytotoxicity is associated with a direct increase of both ROS generation and the expression of Bax protein.

Amyand's Hernia with Periappendicular Abscess

The presence of a vermiform appendix in an inguinal hernia is known as Amyand's hernia. It is rare condition that occurs in about 0.51% of the cases of inguinal hernia. Appendicitis within an Amyand's hernia is found in 0.10% of all forms of external hernia sacs. It is often misdiagnosed as a strangulated inguinal hernia. We experienced a case of Amyand's hernia with a periappendicular abscess within a right inguinal hernia sac in a 71-year-old male patient. Combined appendectomy and Bassini's herniorrhaphy were performed. The patient had an uncomplicated postoperative course and he was discharged 8 days after admission.

Endovascular Management on a May-Thurner Syndrome Patients with Iliac Vein Thrombosis

PURPOSE: We wanted to evaluate the effectiveness of endovascular management for treating patients suffering with May-Thurner syndrome along with left iliac vein thrombosis. METHODS: 11 patients with May-Thurner syndrome underwent treatment from January 2002 to December 2004. We evaluated the symptoms, diagnostic modalities, involved sites, treatment modalities, volume of the thrombolytic agent (urokinase), types of stent, complications and outcomes for each of the patients. RESULTS: The 11 patients were 54+/-15 years old and the male to female ratio was 1 : 2.66. Combined endovascular management was used for all patients. They were diagnosed by radioisotope scan, computed tomographic angiography, color doppler image and conventional venography. Endovascular procedures such as stent insertion, catheter-directed thrombolysis using urokinase infusion, balloon angioplasty and aspirated thrombectomy were used as treatment modalities. We placed the stents into the involved veins in 11 patients. Technical success was achieved in 10 out of 11 patients. Ten patients experienced a successful clinical outcome without any recurrence or complication during the follow-up periods. CONCLUSION: Endovascular management such as stent placement is an effective method for restoring venous patency and it provides relief of the acute symptoms.

Tacrolimus (FK506) Induced Apoptotic Signal Transduction Pathway

PURPOSE: This study examined the effects of Tacrolimus (FK506) on the expression of the apoptotic signal transduction proteins of Jurkat human T-lymphocytes. METHODS: The cell viability was examined by a MTT assay, DAPI stain, enzyme activity of caspase family proteins, and western blotting for Bcl-2, Bak, Fas, and Fas-L. The cells were cultured in the presence or absence of FK506. FK506 induced cell death was confirmed to be apoptosis by the observation of nuclear fragmentation. RESULTS: The viability of Jurkat cells was decreased by the addition of FK506 in a dose- and time- dependent manner. The FK506 induced activation of caspase-3 protease was observed. FK506 didn't increase the catalytic activity of caspase -6, -8, and -9 proteases of Jurkat cells in a time-dependent manner. The viability was improved when a caspase-3 inhibitor was added. However, the caspase-9 inhibitor did not affect the viability. Bak protein expression was increased, and the Bcl-2 protein was decreased for some time. The expression of Fas and Fas-L were unaffected by FK506. CONCLUSION: FK506 induces dose- and time-dependent apoptotic cell death, and enhances the apoptosis of Jurkat cell by increasing the expression of Bak and caspase-3.

Cytotoxic Mechanism of FK506 on Human T Lymphocytes

PURPOSE: FK506 (Tacrolimus) has been widely used as an immunosuppressant. We examined the effects of FK506 on the activation, proliferation and expression of cytotoxic effector molecules of Jurkat human T-lymphocytes. METHODS: We investigated the effects of this compound on cell viability, the production of reactive oxygen species and mitochondrial dysfunction. The cells were cultured in the presence or absence of FK506. Flow cytometric analysis was performed after staining with PI. The viability of the Jurkat cells was decreased by the addition of FK506 in a dose-and time-dependent manners. RESULTS: FK506-induced cytotoxicity was characterized by G0/G1 phase cell-cycle arrest. FK506 induced cell death was confirmed by the caspase-3 protease activation. In addition, the pharmacologic scavenging study of reactive oxygen species (ROS), including H2O2, revealed that cytotoxicity was achieved by the generation of ROS, which might modulate the mitochondrial dysfunction. CONCLUSION: These results suggest that FK506 functions in CDK4-cyclin D1 mediated cell-cycle arrest of Jurkat cells via generation of ROS and mitochondrial dysfunction.