p21Cip1/WAF1 is important for differentiation and survival of U937 cells

Vitamin D3 (VD3) induces monocytic differentiation of U937 cells. Induction of p21Cip1/WAF1 (p21) and subsequent G0/G1 cell-cycle arrest are required in this process. Using a system of inducible expression of ectopic p21, we demonstrated the important role of p21 in the induction of monocytic differentiation in U937 cells. Prior induction of antisense-p21 expression significantly suppressed p21 expression, and resulted in inhibition of VD3-induced U937 differentiation. Moreover, induction of expression of antisense-p21 in VD3-differentiated U937 cells resulted in apoptosis of the cells. This was associated with activation of Cdc2 and caspase-3 like protease. Our results suggest that p21 is required for the initiation of the early steps of differentiation as well as survival of differentiated cells.

Defective control of apoptosis, radiosensitivity, and spindle checkpoint in ataxia telangiectasia

We examined the regulation of apoptosis, radiosensitivity, and spindle checkpoint in response to DNA-damaging agents in ataxia telangiectasia (AT)-derived lymphoblastoid cell lines (AT-LCLs), which lack AT mutated (ATM) protein expression. In addition to the previous findings that AT-LCLs are defective in regulation of cell cycle at the G1, S, and G2-M checkpoints in response to X-ray irradiation (X-IR) and are highly sensitive to X-IR (J. Biol. Chem., 271: 20486-20493, 1996), we showed for the first time that AT-LCLs were defective in X-IR-associated spindle checkpoint control. The cells were also resistant to early apoptosis as much as LCLs derived from patients with Li-Fraumeni syndrome (LFS-LCLs). Terminal deoxynucleotidyl transferase-mediated nick end labeling assay of LCLs, however, demonstrated a significant increase in apoptotic cells among AT-LCLs cultured over a longer period after X-IR. These findings were in contrast to those of LFS-LCL, which showed very little increase in terminal deoxynucleotidyl transferase-mediated nick end labeling-positive population, even in cells with hyperploidy. Thus, although early apoptosis and cell cycle controls in response to DNA damage are disrupted in both ATM and p53 mutations, cells from AT patients are much more susceptible to late-onset apoptosis than those of LFS. These differences may depend on the level of accumulation of DNA damage and/or threshold that triggers late-onset cell death in ATM or p53 mutations. Our findings allow a better understanding of the role of ATM in p53-dependent and independent signal transduction pathways in response to DNA damaging agents.

[A case of adenocarcinoma of the thymus]

We report an adenocarcinoma of the thymus in a 39-year-old male. The patient presented with chest pain, and the chest X-ray film and chest CT showed an abnormal mass in the mediastinum. A preoperative clinical diagnosis of invasive thymoma was suspected. The tumor was resected along with the pleura and pericardium. The pathological findings were compatible with those of adenocarcinoma of the thymus. Despite a thorough examination, no primary tumor could be found. An adenocarcinoma of the thymus is rare and to the authors knowledge there are few previous reports in the literature.

Molecular characterization of phenylketonuria in Japanese patients

We characterized phenylalanine hydroxylase (PAH) genotypes of Japanese patients with phenylketonuria (PKU) and hyperphenylalaninemia (HPA). PKU and HPA mutations in 41 Japanese patients were identified by denaturing gradient gel electrophoresis and direct sequencing, followed by restriction fragment length polymorphism analysis to find a large deletion involving exons 5 and 6. Of 82 mutant alleles, 76 (92%) were genotyped showing 21 mutations. The major mutations were R413P (30.5%), R243Q (7.3%), R241 C (7.3%), IVS4nt-1 (7.3%), T2781 (7.3%), E6nt-96A-->g (6.1%), Y356X (4.9%), R111X (3.7%), and 442-706delE5/6 (2.4%). Eight new mutations (L52 S, delS70, S70P, Y77X, IVS3nt-1, A132 V, W187 C, and C265Y) and a polymorphism of IVS10nt-14 were detected. In vitro PAH activities of mutant PAH cDNA constructs were determined by a COS cell expression system. Six mutations, viz., R408Q, L52 S, R241 C, S70P, V388 M, and R243Q, had 55%, 27%, 25%, 20%, 16% and 10% of the in vitro PAH activity of normal constructs, respectively. The mean pretreatment phenylalanine concentration (0.83+/-0.21 mmol/l) of patients carrying the R408Q, R241 C, or L52 S mutation and a null mutation was significantly lower (P<0.0005) than that (1.99+/-0.65 mmol/l) of patients with both alleles carrying mutations associated with a severe genotype. Simple linear regression analysis showed a correlation between pretreatment phenylalanine concentrations and predicted PAH activity in 29 Japanese PKU patients (y=31.9-1.03x, r=0.59, P<0.0001). Genotype determination is useful in the prediction of biochemical and clinical phenotypes in PKU and can be of particular help in managing patients with this disorder.

An alternatively spliced fibroblast growth factor (FGF)-5 mRNA is abundant in brain and translates into a partial agonist/antagonist for FGF-5 neurotrophic activity

We detected in the brain and then cloned two novel, short forms of human and mouse fibroblast growth factor (FGF)-5 mRNA, which were designated human FGF-5S (hFGF-5S) and mouse FGF-5S (mFGF-5S), respectively. Genomic analysis indicated that mFGF-5S and authentic mFGF-5 mRNAs were transcribed from a single gene; hFGF-5S and mFGF-5S mRNAs were generated by excluding the second exon of the respective FGF-5 genes, and the alternatively spliced mRNAs encoded for 123- and 121-amino acid proteins, respectively. Indeed, a neuron-like cell line expressing mFGF-5S mRNA secreted a protein of the expected size and with FGF-5 antigenicity. In PC12 cells, expression of hFGF-5 or exposure to hFGF-5 protein induced differentiation. Neither expression of hFGF-5S, alone, nor co-expression of hFGF-5S with hFGF-5 induced significant differentiation. At high concentrations, hFGF-5S protein partially antagonized FGF-5 activity, whereas by itself, hFGF-5S exerted very weak neurotrophic activity. hFGF-5S protein binds to FGF receptor (FGFR)-1 on PC12 transfectants and partially inhibits hFGF-5-induced tyrosine phosphorylation of FGFR-1 and an FGFR substrate, but it also induces phosphorylation by itself. These results suggest that FGF-5S is a naturally expressed partial agonist/antagonist of FGF-5 neurotrophic activity in the brain and that its effects are exerted in part at the level of the receptor.

Effect of tylosin tartrate (Tylan Soluble) on cellular immune responses in chickens

Although many antimicrobial agents have been reported to cause immunosuppression in animals, macrolide antibiotics enhance immune function. Tylosin is a macrolide antibiotic approved for the control of mycoplasmosis in poultry. The purpose of this investigation was to determine the effect of tylosin on cellular immune functions in chickens. There was no significant difference in adherent splenocyte chemotaxis between tylosin-treated and untreated (control) chickens. Tylosin increased splenocyte proliferation and splenocyte conditioned medium (CM) proliferative activity above control levels. Removal of adherent splenocytes before preparation of CM caused a reduction in CM proliferative activity. Tylosin also increased antitumor activity of splenocytes. These data are the first to suggest that the macrolide antibiotic, tylosin tartrate, has a modulatory effect in chickens on the immune parameters studied.

Effect of tylosin tartrate on humoral immune responses in chickens

While many antimicrobial agents have been reported to cause immunosuppression in animals, macrolide antibiotics enhance the immune function. Tylosin tartrate is a macrolide antibiotic approved for the control of mycoplasmosis in poultry. The purpose of this investigation was to determine the effect of tylosin on the humoral immune functions in chickens. Three days after oral tylosin tartrate administration, 4- or 8-week-old chickens were immunized intravenously with carbolic acid-killed Brucella abortus bacterin or sheep red blood cells. Seven days (plasma antibodies titre) or 4 days (antibody forming cells) post-immunization, there was a significant increase in antibody production as well as in the numbers of antibody-producing cells in tylosin tartrate-administered chickens compared with the untreated controls. However, 3 days after tylosin tartrate administration, there was no difference in the distribution of T-lymphocyte subpopulations (CD4 or CD8 positive cells) or B lymphocytes (surface immunoglobulin positive cells) in either the peripheral blood or spleens or untreated control chickens.

Dynamics of QT interval in a patient with long QT syndrome and a normal QT interval

A case report of a 15-year-old girl who experienced syncope and torsades de pointes is presented. The girl had a normal QT interval (QTc=0.37 sec) on the resting electrocardiogram (ECG). Infusion of isoproterenol induced QT prolongation (QTc=0.62 sec) and frequent occurrence of multiform ventricular premature beats. Her Holter ECG showed a prolongation of the QTc interval with a shortening of the RR interval. Low-frequency power (LF) and high-frequency power (HF) of heart rate variability were evaluated from the Holter ECG. The patient showed a statistically significant negative QTc/HF and a significant positive QTc/(LF/HF) relationship, whereas none of the age- and sex-matched healthy subjects showed these relationships. The slope of the QT/RR relationship for the patient was below the lower limit of the normal range. This report describes the unusual relationship of QT interval to RR interval and heart rate variability in a long QT syndrome patient with a normal QT interval on resting ECG.

Subependymoma in the lateral ventricle incidentally detected by routine brain examination--case report

A 42-year-old male visited our hospital for a routine brain examination, which incidentally identified an intraventricular mass lesion (2.7 x 1.6 x 1.2 cm3). Magnetic resonance imaging showed the tumor was isointense on the T1-weighted image and hyperintense on the T2-weighted and proton images. The intraventricular tumor was totally extirpated through the interhemispheric ipsilateral transcallosal approach. The histological diagnosis was subependymoma. Neuroimaging cannot differentiate this benign neoplasm from other more aggressive tumors. Widespread use of the medical checkup system is expected to find a higher incidence of otherwise non-identified asymptomatic lesions. Surgical extirpation is one of the treatment options to establish the correct diagnosis and to prevent symptoms.

Control of Theileria sergenti infection by vaccination

Bovine piroplasmosis caused by Theileria sergenti is a major cause of economic loss in grazing cattle in Japan. Infected calves show chronic anaemia with intraerythrocytic piroplasms and occasionally die in severe cases. We found that parasite stocks and isolates consist of genetically and antigenically mixed populations. To differentiate parasite populations bearing 3 allelic forms of p32/34, an immunodominant piroplasm surface protein, 3 sets of oligonucleotide primers were designed to amplify either of 3 alleles by polymerase chain reaction (PCR). By using this allele-specific PCR, we found that the majority of T. sergenti-infected calves in Japan harbored mixed parasite populations bearing C and I type parasites. To control Theileria infection, we produced 2 vaccine candidates: recombinant baculovirus p32 and synthetic peptide containing Lys-Glu-Lys (KEK) motif. Immunization with either recombinant p32 or synthetic peptide containing KEK sequences with Freund's complete adjuvant resulted in low parasitemia and reduced the clinical symptoms compared to control calves. Interestingly, the parasite with the p32 allelic form corresponding to the one used as the immunogen was suppressed.

Cerebellopontine angle ependymoma with internal auditory canal enlargement and pineal extension--case report

A 38-year-old male presented with a posterior fossa ependymoma with unusual extension from the cerebellopontine angle to the pineal region. Magnetic resonance imaging clearly demonstrated that these two components were continuous through the right ambient cistern. Computed tomography using a bone algorithm revealed enlargement of the right internal auditory canal. This case suggests that ependymoma can extend anywhere within the subarachnoid space along the path of least resistance.

Quantitative assays for hepatitis C virus in serum as predictors of the long-term response to interferon

BACKGROUND/AIMS

Interferon therapy has a beneficial effect in patients with chronic hepatitis C who have a low viral load. The aim of this study was to compare the core protein level with HCV RNA levels and to analyze whether virus quantitation predicts the efficacy of interferon therapy.

METHODS

HCV core protein level assessed by the recently developed assay was compared with HCV RNA levels measured by three different methods (Amplicor-HCV monitor, competitive RT(CRT)-PCR, and bDNA probe assay) in 352 patients with chronic hepatitis C in relation to viral serotype.

RESULTS

From 91% (320/352) to 93% (299/322) of patients with viremia were detected by Amplicor-monitor and CRT-PCR, in contrast to 60% (187/312) and 74% (191/258) by bDNA and HCV core protein assay, respectively. The HCV core protein level was positively correlated with HCV RNA levels measured by the three assays (r = 0.680 to 0.731). Serum HCV RNA and core protein levels were significantly lower in patients with serotype 2 than in those with serotype 1. Viral eradication after interferon therapy was observed in 60-70% of the patients with < 1 x 10(4) copies/ml of HCV RNA by Amplicor-monitor assay, < 2 x 10(5) copies/ml by CRT-PCR, < 0.5 Meq/ml by bDNA assay, and < 20 pg/ml of core protein by HCV core protein assay. Viral eradication was uncommon (< 11%) among the patients with higher viral loads. Bivariate analysis revealed that the outcome of interferon therapy was more closely associated with both HCV core protein and RNA levels than the HCV serotype.

CONCLUSIONS

Quantitation of HCV core protein and HCV RNA in useful for prediction of the interferon response.

An ulcerated lesion at the BCG vaccination site during the course of Kawasaki disease

We describe a bacillus Calmette-Guérin (BCG) granuloma that occurred during the course of Kawasaki disease. A 12-month-old male infant with Kawasaki disease had an erythematous indurated plaque with prominent necrotic ulceration at the BCG vaccination site on the left upper arm. Histologic study showed a granulomatous reaction consisting of epithelioid histiocytes, lymphoid cells, and Langhans-type giant cells. No evidence of mycobacterial infection was obtained. The lesion healed completely within 2 weeks without administration of antituberculous agents. We believe that the granulomatous reaction occurred as a result of hypersensitivity to proteins in the BCG vaccine, which appeared after the onset of Kawasaki disease.

Predictors of the efficacy of interferon therapy in chronic hepatitis C virus infection. Tokyo-Chiba Hepatitis Research Group

BACKGROUND & AIMS

The relative role of virus load and hepatitis C virus (HCV) subtype as predictor of the efficacy of interferon (IFN) therapy is still in dispute. To resolve this issue, a multicenter, randomized, prospective study of 272 patients with chronic hepatitis C but without cirrhosis was conducted.

METHODS

The patients were randomly assigned to two different dose groups: 6 million units (MU) or 9 MU IFN three times a week for 6 months. Serum HCV RNA levels and HCV subtypes were determined.

RESULTS

HCV RNA negativity rate at the completion of treatment with 9 MU IFN was higher than that with 6 MU (75% vs. 44%; P < 0.05). Virus eradication at 12 months after completion of treatment was higher in the 9 MU group than in the 6 MU group (36% vs. 25%; P < 0.05), especially in patients who had an intermediate virus load (10(4)-10(5) copies/mL by Amplicor monitor assay) (52% vs. 19%; P = 0.029). Virus eradication rate in patients with serotype 2 was higher than in those with serotype 1 for both regimens (6 MU, 53% vs. 15%; 9 MU, 76% vs. 29%; each P < 0.05).

CONCLUSIONS

This prospective study showed that virus load, HCV serotype, and IFN dose are important predictors of the virological response to IFN therapy but virus load is the most important factor influencing the efficacy of IFN.

Inhibitory effect of alginic acids on hyaluronidase and on histamine release from mast cells

The effects of various types of alginic acid consisting of L-guluronic acids (G) and D-mannuronic acids (M) on hyaluronidase and mast cell degranulation were examined. Alginic acid with an M/G ratio of 1.0 exhibited the strongest inhibition of both activities, the higher molecular weight alginic acids of 150 to 370 kDa being preferable in both cases. Esterification of the carboxyl residue enhanced the latter activity.

DNA damage-associated dysregulation of the cell cycle and apoptosis control in cells with germ-line p53 mutation

Lymphoblastoid cell lines (LCLs) with heterozygous p53 mutations at residues 286A, 133R, 282W, 132E, and 213ter were established from five independent Li-Fraumeni syndrome families. When cell cycle regulation in response to gamma-irradiation was studied, these LCLs showed an abnormal G1 checkpoint associated with defective inhibition of cyclin E/cyclin-dependent kinase 2 activity in all cases except for 282W LCL, which showed a normal G1 checkpoint. On the other hand, the control of S-phase-G2 as determined by cyclin A/cyclin-dependent kinase 2 activity was defective in all these LCLs. The mitotic checkpoint was also defective in the two LCLs analyzed as either competent or incompetent for G1 arrest. When radiation-induced apoptosis, which requires wild-type p53 function under optimal conditions, was studied, all of these LCLs showed significant failure compared to normal LCLs. These findings indicate that although p53-dependent transactivation and G1-S-phase cell cycle control are variably dysregulated, the induction of apoptosis and control of the cell cycle at S-phase-G2 and the mitotic checkpoint in response to DNA-damaging agents are consistently dysregulated in heterozygous mutant LCLs. This suggests that these dysfunctions underlie, at least in part, the susceptibility of Li-Fraumeni syndrome families to cancer. Furthermore, the approach presented is a potentially useful method for studying individual carriers of different germ-line p53 mutations and different biological features.

The in vitro effects of all-trans-retinoic acid and hematopoietic growth factors on the clonal growth and self-renewal of blast stem cells in acute promyelocytic leukemia

All-trans-retinoic acid (ATRA) has been used as a potent therapeutic agent to induce differentiation of acute promyelocytic leukemia (APL) cells, and granulocyte colony-stimulating factor (G-CSF) has been reported to enhance this effect of ATRA in vitro. We investigated the effects of ATRA and three myeloid growth factors, including G-CSF, on the growth of the leukemic stem cells of 10 APL patients. G-CSF was the most powerful stimulator of leukemic colony formation in five out of 10 patients, but was neither the major stimulant of self-renewal of the blast stem cells nor an inducer of maturation. In contrast, ATRA was highly effective in inducing morphological maturation of leukemic promyelocytes, but variable results were obtained in regard to its effects on the growth of blast stem cells: ATRA suppressed both clonal growth and self-renewal in some patients, but was inactive or even had stimulating effects in the other patients. Similar variable effects were observed with the combination of ATRA and G-CSF. These findings indicate that the differentiation-inducing effect of ATRA is not always associated with growth inhibition of leukemic stem cells in vitro and justify the use of chemotherapy in conjunction with ATRA in the treatment of APL.

Operative results of thoracoabdominal repair for chronic type B aortic dissection

From January 1991 to May 1994, we have operated on 15 cases of Type B aortic dissection. In 10 of these patients, thoracoabdominal repair was performed. According to Crawford's classification, 2 patients fell into Type I, 6 patients into Type II, and 2 patients into Type III. The aneurysms were exposed through a left thoracotomy extending into the retroperitoneum with the hemidiaphragm divided circumferentially. The operations were performed under femoro-femoral partial cardiopulmonary bypass. In 6 of these cases selective perfusion of the visceral branches was used. The celiac axis was reconstructed in 10 patients, superior mesenteric artery in 9, right renal artery in 7, left renal artery in 6. Abdominal vessels were reconstructed by the "inclusion" technique described by Crawford in 2 patients, by "beveling" the distal prosthetic end in 6 and by the "interposition" technique in 4 patients. Vessels arising from the false lumen were reconstructed by the "interposition" technique. To prevent paraplegia, the evoked spinal cord potentials by direct stimulation of the cord (ESPs-dsc) were monitored perioperatively and the aneurysms were repaired sequentially in segments. In all patients except 2 with Crawford type III aneurysms, spinal cord ischemia was detected by ESPs-dsc. In 7 of these patients, 2 to 8 pairs of intercostal/lumbar arteries (I/L aa.) that arose from the "responsible" aortic segment were reconstructed. Reconstruction techniques included the "inclusion" technique in 2 patients, the "beveling" technique in 1, the "interposition" technique in 1 and the "on lay grafting" technique in 3 patients. One hospital death occurred in a patient who had chronic renal insufficiency and liver cirrhosis preoperatively. Spinal cord injury occurred in 5 patients, including 4 paraparesis and 1 delayed-onset paraplegia. In 2 of these patients, responsible I/L aa., were not reconstructed correctly despite ESPs changes, and injury might have been prevented if reconstruction of the "responsible" arteries had been performed. Thoracoabdominal repair for chronic Type B aortic dissection could be performed safely with an acceptable mortality rate. Spinal cord injury remains an unsolved problem.

Increased expression of highly branched N-glycans at cell surface is correlated with the malignant phenotypes of mouse tumor cells

Three NIH3T3 transformants, MTAg, MTPy, and MT1, which grow similarly in soft agar media, showed remarkable differences in athymic mice: MTAg grew more rapidly than MTPy, whereas MT1 and NIH3T3 did not, and only MTAg metastasized in lung. Structural analysis of N-glycans from plasma membrane glycoproteins revealed that each sample contains similar amounts of N-glycans, but the relative amounts of 2,6-branched tri- and tetra-antennary oligosaccharides prominently increase and the relative amounts of biantennary oligosaccharides prominently decrease in the order of NIH3T3, MT1, MTPy, and MTAg, whereas those of others remained constant. Western blot analysis revealed that binding of Datura stramonium agglutinin, which interacts with 2,6-branched tri- and tetra-antennary oligosaccharides, is significantly increased in several bands from MTAg compared with NIH3T3, two of which are tentatively identified as lysosome-associated membrane protein-1 and fibronectin (FN)-receptor. It was also shown that the spreading of MTAg on FN-coated plates is dramatically inhibited with the anti-FN-receptor antiserum when compared with NIH3T3. These results indicate that the increased expression of highly branched N-glycans at cell surface is correlated with the rapidness of tumor formation and altered adhesive properties of tumor cells in vivo.

[A case of traumatic extracranial internal carotid artery dissecting aneurysm treated by proximal ligation and STA-MCA bypass]

We present a case with the traumatic extracranial internal carotid artery dissecting aneurysm. A 21-year-old man was involved in a motorcycle accident, resulting in multiple injuries but no apparent head and neck injuries. Head CT was normal on his admission. He was discharged from his local hospital 3 weeks after the accident without any neurological deficits. Five weeks after the accident, he suddenly presented with a motor aphasia and a right hemiparesis. CT and MRI showed infarctions in the left para-Sylvian and the left angular areas. Angiography showed a left extracranial carotid artery dissecting aneurysm at the level of C1 vertebral arch. The patient was initially managed by an anticoagulant agent, but he suffered from another transient ischemic attack due to distal embolism from the aneurysm. Balloon occlusion test of the left ICA was performed under monitoring EEG, SEP. Mean stump pressure (MSP) revealed 60 mmHg. and MSP/Mean systematic blood pressure revealed 67%. We judged that the left ICA ligation was a safe method to treat this patient, however, considering the patient's age and the side of the lesion, left STA-MICA bypass and ligation of the left ICA were carried out in one stage. Postoperatively, the patient did not show any cerebral ischemic complications and angiography showed disappearance of the aneurysm and patency of the bypass. The left MCA territories were filled well by cross circulation and the bypass.

[Effect of factor XIII on intractable CSF leakage after a transpetrosal-approach operation: a case report]

The authors reported an experience showing that the XIII factor was effective for intractable cerebrospinal fluid (CSF) leakage after a transpetrosal operation to deal with cerebellopontine angle meningioma. A 63-year-old female noted a slight headache and a floating feeling. She became dependent on a stick for walking alone because of gradual gait disturbance. As the headache became more severe, she consulted the outpatient clinic of the department of neurosurgery of Kobe University Hospital. Magnetic resonance images (MRI) revealed a 4.3 x 3.0cm sized right cerebellopontine angle tumor. She was admitted for the purpose of removal of the tumor and preoperative examinations were performed. Neurological findings on admission showed only slight right cerebellar signs. The operation was performed via the transpetrosal approach and the tumor was totally removed (Simpson Grade II). It took 12 hours 40 minutes for the operation. The amount of blood loss was 1970ml and the blood transfusion volume was 1200ml. Postoperative course was uneventful and her complaints disappeared. There were no postoperative complications at all, but 2 weeks after the operation, CSF leakage under the skin flap appeared. As subcutaneous fluid collection after skull base surgery is usual, spinal drainage and compression of the skin flap was carried out but these measures were not effective. The collection of fluid did not disappear for 2 weeks. Based on our successful experience with the XIII factor therapy in intractable cerebrospinal fluid leakage from the nose after a transsphenoidal approach operation for recurrent pituitary adenoma, the blood level of the XIII factor activity was examined. As the result was far below the normal limit in this case, the XIII factor was infused at a rate of 750 units per day for 5 days. One week after the administration, the level of the XIII factor became normal. Fluid collection disappeared and the drainage tube was removed. Recently, in neurosurgery, skull base surgery has been used widely and the range of craniotomy has been extended because operations can now be performed without compression of cerebral cortexes. However, operation time has increased and the volumes of bleeding and of blood transfusion are increasing. Postoperative complications such as CSF leakage and infection have become new problems. In this case, the XIII factor was still far below the normal level 2 weeks after the operation and it could be considered to have caused delayed CSF leakage. Some papers have reported that the XIII factor was effective in treating intractable fistula after operations in other surgical areas. However, this is the first report of skull base surgery such as an operation using transpetrosal approach taking advantage of the effect of the XIII factor.