NT-pro BNP level at dialysis initiation is a useful biomarker for predicting hospitalization for ischemic heart disease

BACKGROUND

Patients with end-stage kidney disease (ESKD) are at high risk of cardiovascular disease including stroke, heart failure, and ischemic heart disease (IHD). To prevent the occurrence and progression of CVD, a reliable prognostic cardiac biomarker is essential. We investigated the prognostic value of NT-proBNP for each incident type of CVD.

METHODS

Male patients from the Ibaraki Dialysis Initiation Cohort (iDIC) study with preserved serum samples from dialysis initiation day (n = 212) were analyzed. Patients were classified into four groups according to quartiles of baseline NT-pro BNP levels. The relationship between NT-proBNP levels at the initiation of dialysis and the subsequent incidence of hospitalization events due to IHD, heart failure, and stroke was analyzed.

RESULTS

The incidence rate for hospitalization due to IHD was significantly higher in the highest NT-proBNP category (Log rank p = 0.008); those of stroke and heart failure showed no significant differences among quartiles. Cox proportional hazards regression analysis revealed that serum NT-proBNT was the only prognostic factor for hospitalization for IHD after adjustment by major known IHD risk factors. (HR, 1.008; 95% confidence interval, 1.002-1.014; p = 0.01) The ROC curve analysis for the incidence of hospitalization due to IHD showed that NT-proBNP had an area under the curve (AUC) of 0.759 (95% CI 0.622-0.897; p = 0.004) at a cut-off value of 956.6 pg/mL.

CONCLUSION

NT-proBNP measurement at the initiation of dialysis therapy is useful to predict later hospitalization for IHD.

TRIAL REGISTRATION

UMIN000010806.

Introduction of Extracorporeal Membrane Oxygenation on Ninth Day of Ventilator Management for Severe Acute Respiratory Distress Syndrome due to COVID-19: A Case Report

The reported case is of a 68-year-old man who was admitted to the ICU at our tertiary care medical center with severe COVID-19. He was admitted to the ICU due to a worsening respiratory condition during his hospitalization at the same medical center, which included the development of severe acute respiratory distress syndrome (ARDS). Ventilator management was started with alveolar protection in mind. On the ninth day of ventilator management, we judged that it was necessary to introduce extracorporeal membrane oxygenation (ECMO). Although the ninth day of ventilator management is considered relatively late for starting ECMO, there are no absolute contraindications for ECMO at this stage, and improvements in oxygenation can be expected. After introducing ECMO, the patient’s oxygenation capacity improved, and ECMO was successfully withdrawn within 16 days. The patient required long-term rehabilitation but was discharged from the hospital to his home without lingering disease complications on the 150th day of illness and subsequently resumed his former work, daily activities, and quality of life. We conclude that, in regard to the introduction of ECMO for ARDS, it is necessary to reach a comprehensive judgment without being bound by any one index (such as the ventilation management period prior to ECMO introduction).

Major hepatectomy with combined vascular resection for perihilar cholangiocarcinoma

Background

Hepatectomy with vascular resection (VR) for perihilar cholangiocarcinoma (PHCC) is a challenging procedure. However, only a few reports on this procedure have been published and its clinical significance has not been fully evaluated.

Methods

Patients undergoing surgical resection for PHCC from 2002–2017 were studied. The surgical outcomes of VR and non-VR groups were compared.

Results

Some 238 patients were included. VR was performed in 85 patients. The resected vessels were hepatic artery alone (31 patients), portal vein alone (37 patients) or both (17 patients). The morbidity rates were almost the same in the VR (49.4 per cent) and non-VR (43.8 per cent) groups (P = 0.404). The mortality rates of VR (3.5 per cent) and non-VR (3.3 per cent) were also comparable (P > 0.999). The median survival time (MST) was 45 months in the non-VR group and 36 months in VR group (P = 0.124). Among patients in whom tumour involvement was suspected on preoperative imaging and whose carbohydrate antigen 19-9 (CA19-9) value was 37 U/ml or less, MST in the VR group was significantly longer than that in the non-VR group (50 versus 34 months, P = 0.017). In contrast, when the CA19-9 value was greater than 37 U/ml, MST of the VR and non-VR groups was comparable (28 versus 29 months, P = 0.520).

Conclusion

Hepatectomy with VR for PHCC can be performed in a highly specialized hepatobiliary centre with equivalent short- and long-term outcomes to hepatectomy without VR.

Utility of remnant liver volume for predicting posthepatectomy liver failure after hepatectomy with extrahepatic bile duct resection

BACKGROUND

Hepatectomy with extrahepatic bile duct resection is associated with a high risk of posthepatectomy liver failure (PHLF). However, the utility of the remnant liver volume (RLV) in cholangiocarcinoma has not been studied intensively.

METHODS

Patients who underwent major hepatectomy with extrahepatic bile duct resection between 2002 and 2018 were reviewed. The RLV was divided by body surface area (BSA) to normalize individual physical differences. Risk factors for clinically relevant PHLF were evaluated with special reference to the RLV/BSA.

RESULTS

A total of 289 patients were included. The optimal cut-off value for RLV/BSA was determined to be 300 ml/m2. Thirty-two patients (11.1 per cent) developed PHLF. PHLF was more frequent in patients with an RLV/BSA below 300 ml/m2 than in those with a value of 300 ml/m2 or greater: 19 of 87 (22 per cent) versus 13 of 202 (6.4 per cent) (P < 0.001). In multivariable analysis, RLV/BSA below 300 ml/m2 (P = 0.013), future liver remnant plasma clearance rate of indocyanine green less than 0.075 (P = 0.031), and serum albumin level below 3.5 g/dl (P = 0.015) were identified as independent risk factors for PHLF. Based on these risk factors, patients were classified into three subgroups with low (no factors), moderate (1-2 factors), and high (3 factors) risk of PHLF, with PHLF rates of 1.8, 14.8 and 63 per cent respectively (P < 0.001).

CONCLUSION

An RLV/BSA of 300 ml/m2 is a simple predictor of PHLF in patients undergoing hepatectomy with extrahepatic bile duct resection.

An Adult Patient with Alagille Syndrome Showing Mainly Renal Failure and Vascular Abnormality without Liver Manifestation

Alagille syndrome is an inherited multisystemic disorder. We herein report an atypical case of a Japanese adult patient with Alagille syndrome. He had been diagnosed with Alagille syndrome as an infant based on a liver biopsy. At 27 years of age, he needed to start hemodialysis therapy, but an arteriovenous fistula was not created because his peripheral blood vessels were too narrow. He also had a recurrent brain infarction due to cerebral vascular stenosis. Alagille syndrome is generally recognized as a pediatric hepatic disease, but general physicians should be aware of its potential existence with renal involvement and vascular abnormalities.

Serum 20S proteasome levels are associated with disease activity in MPO-ANCA-associated microscopic polyangiitis

Background

Proteasomes are found in both the cell nucleus and cytoplasm and play a major role in the ubiquitin-dependent and -independent non-lysosomal pathways of intracellular protein degradation. Proteasomes are also involved in the turnover of various regulatory proteins, antigen processing, cell differentiation, and apoptosis. To determine the diagnostic value of serum proteasome in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), we investigated patients with AAV at various stages of the disease.

Methods

Serum 20S-proteasome was measured by ELISA in 44 patients with MPO-ANCA-associated microscopic polyangiitis (MPA) and renal involvement. Thirty of the patients provided serum samples before the initial treatment, and 30 provided samples during remission; 16 provided samples at both time points.

Results

The mean serum 20S-proteasome level was significantly higher in the active-vasculitis patients (3414.6 ± 2738.9 ng/mL; n = 30) compared to the inactive-vasculitis patients (366.4 ± 128.4 ng/mL; n = 30; p <  0.0001) and 40 controls (234.9 ± 90.1 ng/mL; p <  0.0001). There were significant positive correlations between the serum 20S-proteasome level and the Birmingham Vasculitis Activity Score (BVAS) (r = 0.581, p <  0.0001), the ANCA titer (r = 0.384, p <  0.0001), the white blood cell (WBC) count (r = 0.284, p = 0.0042), the platelet count (r = 0.369, p = 0.0002), and the serum C-reactive protein (CRP) level (r = 0.550, p < 0.0001). There were significant negative correlations between the serum 20S-proteasome level and both the hemoglobin concentration (r = - 0.351, p = 0.0003) and the serum albumin level (r = - 0.460, p < 0.0001). In a multiple regression analysis, there was a significant positive correlation between the serum 20S-proteasome level and only the BVAS results (β = 0.851, p = 0.0009). In a receiver operating curve analysis, the area under the curve for the serum 20S-proteasome level was 0.996, which is higher than those of the WBC count (0.738) and the serum CRP level (0.963).

Conclusion

The serum level of 20S-proteasome may be a useful marker for disease activity in AAV.

Clinical course and pathological findings of two late-onset Fabry hemizygous patients including mulberry cell counts after enzyme replacement therapy

Fabry disease is an X-linked inherited lysosomal storage disorder caused by a deficiency of α-galactosidase A activity, resulting in the intracellular accumulation of globotriaosylceramide and related glycosphingolipids. The phenotypes of Fabry disease in both males and females are grouped into two categories: the classical type and the late-onset type. The classical type shows general symptoms including angiokeratoma(s), acroparesthesia, hypohidrosis, corneal opacity, and gastrointestinal symptoms from an early age. The late-onset type shows cardiac or renal (or both) symptoms from a late age. We present herein the clinical course and pathological findings of two late-onset hemizygous Fabry patients after the initiation of enzyme replacement therapy (ERT), along with their mulberry cell counts during treatment. One patient's case was a renal-variant type without general symptoms; he showed stable renal function and mild proteinuria but little histological improvement with no change in the mulberry cell count during ERT. The other patient had a cardiac-variant type with renal pathological abnormality. He achieved a mild improvement of renal pathological findings, and his mulberry cell count gradually decreased during the treatment. These findings indicate that monitoring the mulberry cell count might help assess the efficacy of ERT, as a renal pathology tool.

Prognostic role of the length of tumour-vein contact at the portal-superior mesenteric vein in patients having surgery for pancreatic cancer

BACKGROUND

The length of tumour-vein contact between the portal-superior mesenteric vein (PV/SMV) and pancreatic head cancer, and its relationship to prognosis in patients undergoing pancreatic surgery, remains controversial.

METHODS

Patients diagnosed with pancreatic head cancer who were eligible for pancreatoduodenectomy between October 2002 and December 2016 were analysed. The PV/SMV contact was assessed retrospectively on CT. Using the minimum P value approach based on overall survival after surgery, the optimal cut-off value for tumour-vein contact length was identified.

RESULTS

Among 491 patients included, 462 underwent pancreatoduodenectomy for pancreatic head cancer. PV/SMV contact with the tumour was detected on preoperative CT in 248 patients (53·7 per cent). Overall survival of patients with PV/SMV contact exceeding 20 mm was significantly worse than that of patients with a contact length of 20 mm or less (median survival time (MST) 23·3 versus 39·3 months; P = 0·012). Multivariable analysis identified PV/SMV contact longer than 20 mm as an independent predictor of poor survival, whereas PV/SMV contact greater than 180° was not a predictive factor. Among patients with a PV/SMV contact length exceeding 20 mm on pretreatment CT, those receiving neoadjuvant therapy had significantly better overall survival than patients who had upfront surgery (MST not reached versus 21·6 months; P = 0·002).

CONCLUSION

The length of PV/SMV contact predicts survival, and may be used to suggest a role for neoadjuvant therapy to improve prognosis.

The relationship between serum magnesium levels and mortality in non-diabetic hemodialysis patients: A 10-year follow-up study

Introduction Recently, although there are many reports showing that serum magnesium concentration is a predictor of mortality in dialysis patients, the observation periods of those reports were of short duration, typically around 12 months. Thus, we investigated this relationship over a longer follow-up period. Methods This retrospective, observational study included a total of 83 non-diabetic hemodialysis patients. The follow-up period was 120 months. Patients were divided into two groups, those with serum magnesium ≥2.5 mg/dL (Mg ≥2.5 mg/dL group) and serum magnesium <2.5 mg/dL (Mg <2.5 mg/dL group), and Kaplan-Meier analysis and Cox proportional hazards analysis were conducted. In addition to the above analysis, single and multiple regression analysis were performed at baseline to reveal the relationship between serum magnesium and clinical parameters. Findings During the follow-up period, 31 out of 83 patients died. Kaplan-Meier analysis showed a significantly higher incidence of death in the Mg <2.5 mg/dL group (log-rank test 4.951, P = 0.026). Multivariate Cox proportional hazards analysis showed a 62% decreased risk of mortality in the Mg ≥2.5 mg/dL group compared to the Mg <2.5 mg/dL group after adjustment for several confounding factors. Simple correlation coefficient analysis showed positive correlations of serum magnesium levels with serum creatinine, phosphorus, high-density lipoprotein, ankle-brachial index and KT/V, and a negative correlation with age. Multiple linear regression analysis showed that the ankle-brachial index was the only parameter that had a positive and significant correlation with the serum magnesium level. Conclusion Our study demonstrated that higher serum magnesium levels were associated with improved survival in non-diabetic hemodialysis patients.

Microscopic polyangiitis associated with thymic tumor: a case report and review of the literature

Background

Thymic hyperplasia and thymic epithelial tumor (thymoma) have been associated with a variety of autoimmune diseases. Renal involvement has been reported in patients with thymoma. Minimal change disease and membranous nephropathy are frequently observed in glomerular lesions of thymoma patients, but ANCA-associated renal vasculitis is rare. We present a case of thymoma-associated microscopic polyangiitis with positivity for three ANCAs: MPO-ANCA, PR3-ANCA and azurocidin-ANCA.

Case presentation

An 89-year-old Japanese woman was admitted to our hospital following an episode of general fatigue, nausea, muscle weakness of the lower limbs, and ophthalmoplegia. On urinalysis, proteinuria, hematuria, and cellular casts were observed. Elevated levels of serum creatinine and C-reactive protein were also demonstrated, and MPO-, PR3- and azurocidin-ANCA were detected on serological examination. Renal biopsy showed pauci-immune crescentic glomerulonephritis. We therefore diagnosed rapidly progressive glomerulonephritis due to microscopic polyangiitis. Acetylcholine-receptor antibody was also detected. Chest computed tomography and MRI revealed a lobulated tumor in the anterior mediastinum. We thus also diagnosed myasthenia gravis with thymoma.

Conclusion

Considering the patient’s triple-ANCA positivity, thymic diseases may be associated with the pathogenesis of ANCA-associated vasculitis due to central T-cell tolerance. A further accumulation of cases is needed, because thymectomy does not always induce the remission of thymoma-associated autoimmune diseases.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1319-9) contains supplementary material, which is available to authorized users.

Primary Structure of a Base Non-specific and Adenylic Acid Preferential Ribonuclease from the Fruit Bodies ofLentinus edodes

The complete primary structure of a base non-specific and adenylic acid preferential RNase (RNase Le2) from the fruit bodies of Lentinus edodes was analyzed. The sequence was mostly determined by analysis of the peptides generated by V8 protease digestion and BrCN cleavage (including alpha-chymotryptic, and V8 protease digest of BrCN fragments). It consists of 239 amino acid residues. The molecular weight is 25831. The location of 10 half cystine residues were almost superimposable on those of known fungal RNases of the RNase T2 family. The sequence homologies between RNase Le2 and four known fungal RNases of the RNase T2 family, RNase T2, RNase M, RNase Trv, and RNase Rh, are 102, 103, 109, and 74, respectively. The homologous sequences are concentrated around the three histidines, which are supposed to form the active site of RNase T2 family RNases.

Primary tumour resection of tongue carcinoma based on response to preoperative therapy

The purpose of this study was to investigate the selection of resection techniques for primary lesions of advanced tongue carcinoma based on the effectiveness of our current preoperative therapy. Forty-three patients with advanced but potentially resectable squamous cell carcinoma of the tongue were included in this study. All patients were treated with preoperative concurrent chemoradiotherapy followed by conventional surgical resection. Semiserial sections of whole surgical specimen of primary lesion were evaluated histopathologically. In patients who achieved 85% and above regression, the extent of residual tumours two-dimensionally and in the deep layers was lesser, and the rate of tumour cell survival was lower, than in other patients. Furthermore, residual tumours tended to be localized to the superficial layers in the centre. These findings suggest that even in advanced tongue carcinomas it is possible to avoid extended resection and perform a less invasive surgery in which the extent of resection is reduced to preserve morphology and function in patients who achieved 65% and above regression following preoperative chemoradiotherapy.

Enzymatic properties of sialic acid binding lectin from Rana catesbeiana modified with a water-soluble carbodiimide in the presence of various nucleophiles

The anti-tumor activity of sialic acid binding lectin from Rana catesbeiana (cSBL) was increased by chemical modification with a water-soluble carbodiimide (EDC) in the presence of nucleophiles such as ethylenediamine and glycine methylester. Investigations on ribonuclease (RNase) activities of the modified cSBLs were conducted to elucidate the fundamental mechanisms underlying enhancement of the anti-tumor activity conferred by these modifications. The following three characteristics were observed with modification. (i) RNase activity of the modified cSBL was enhanced towards double stranded RNA and RNA-oligo dA hybrids. The activity increase was observed even under physiologic ionic strength conditions; (ii) RNase activity of the modified cSBL towards single stranded RNA and poly U decreased, while the activity towards poly C was unaffected; (iii) the base preference of the B2 base recognition site of modified cSBL decreased for guanine. On the contrary, the preference for cytosine and adenine increased. This result may explain why the RNase activity towards poly C was not affected by EDC-modification as mentioned above.

Amino acid sequence of a trypsin inhibitor from a Spirometra (Spirometra erinaceieuropaei)

A trypsin inhibitor that is highly homologous with bovine pancreatic trypsin inhibitor (BPTI) was co-purified along with RNase from Spirometra (Spirometra erinaceieuropaei). The amino acid sequence of this inhibitor (SETI) and the nucleotide sequence of the cDNA encoding this protein were determined by protein chemistry and gene technology. SETI contains 68 amino acid residues and has a molecular mass of 7,798 Da. SETI has 31 amino acid residues that are identical with BPTI's sequence, including 6 half-cystine and 5 aromatic amino acid residues. The active site Lys residue in BPTI is replaced by an Arg residue in SETI. SETI is an effective inhibitor of trypsin and moderately inhibits a-chymotrypsin, but less inhibits elastase or subtilisin. SETI was expressed by E. coli containing a PelB vector carrying the SETI encoding cDNA; an expression yield of 0.68 mg/l was obtained. The phylogenetic relationship of SETI and the other BPTI-like trypsin inhibitors was analyzed using most likelihood inference methods.

Effect of modification of the carboxyl groups of the sialic acid binding lectin from bullfrog (Rana catesbeiana) oocyte on anti-tumor activity

The sialic acid binding lectin from bullfrog Rana catesbeiana oocyte (cSBL) is known to have anti-tumor activity. In order to investigate the relationship between the net charge of cSBL and its anti-tumor effect, cSBL was modified with a water-soluble carbodiimide (EDC) in the presence of three kinds of nucleophiles, taurine, glycine methylester and ethylenediamine. cSBL having four carboxyl groups was partially modified (ca. 2 residues). The anti-tumor activity of modified cSBLs was in the order of ethylenediamine-modified cSBL > glycine methylester-modified cSBL > taurine modified cSBL > or = native cSBL. The results suggested that anti-tumor activity seems to increase with the increase in positive net charge, possibly enhancing the interaction of cSBL with sialoglycoprotein on the surface of tumor cells. The ribonuclease activity of ethylenediamine-modified cSBL decreased with the progress of the reaction, but the number of internalized molecules in the tumor cell increased. Thus, for antitumor activity, a higher incorporation of cSBL with reasonable RNase activity seems to be more important than total RNase activity.

Amino acid sequence and characterization of a rice bran ribonuclease

A base-nonspecific and acid ribonuclease (RNase Os) belonging to the RNase T2 family was purified from rice bran to a homogeneous state by SDS-PAGE. The primary structure of RNase Os was determined by protein chemistry and molecular cloning. The RNase Os was a simple protein and consisted of 205 amino acid residues. Its molecular weight was 22578 and its amino acid sequence showed that it was most similar to barley RNase among the known RNase T2 family enzymes having 157 amino acid residues identical with barley RNase. However, its N-terminus was blocked by a gamma-pyroglutamyl residue. The optimal pH of RNase Os was around 5.5. The base preference at the B1 and B2 site of RNase Os was estimated from the rates of hydrolysis of 16 dinucleoside phosphates, to be guanine as the case of RNase LE from tomato. RNase Os was successfully expressed from yeast cells using the E. coli yeast expression vector pYE-RNAP.

[MR hydrography of the abdomen: technical consideration of data acquisition and future prospects for clinical applications]

Recent advances in MR hydrography have enabled various clinical applications in the areas of abdominal and pelvic disorders, for example, MR cholangiopancreatography (MRCP), MR urography(MRU), and MR hydrography of the fetus. Although the two-dimensional(2D) single-slice method provides excellent information as to the global relationship between lesions and various anatomical structures, small lesions or detailed anatomical characteristics may not be visualized owing to the partial volume effect. Source images of the 2D multislice method are most suitable for the detection of small lesions and detailed evaluation of anatomical structures as "tomographic imaging", while the three-dimensional(3D) method is useful in obtaining data sets for 3D imaging. MR hydrography is a promising method for the noninvasive evaluation of various abdominal disorders, and it has the potential to play new roles in various anatomical regions. However, knowledge of the proper indications is essential for successful clinical application.

Primary non-Hodgkin's lymphoma of the mandible treated with radiotherapy, chemotherapy, and autologous peripheral blood stem cell transplantation

Extranodal presentation in non-Hodgkin's lymphoma (NHL) is uncommon, and the mandible is very rarely involved. Primary NHL of the mandible, for the most part, has intermediate or high malignancy and has a much greater incidence of local recurrence compared with other sites of involvement. A 48-year-old Japanese man with NHL of the mandible received radiotherapy, followed by high-dose chemotherapy supported with peripheral blood stem cell transplantation (PBSCT). High-dose cyclophosphamide, Adriamycin, and vincristine were used for pretransplant conditioning. He achieved complete remission and has survived in continuous complete remission for more than 72 months to date. Marrow-ablative chemotherapy facilitated by PBSCT is thought to be useful as part of the primary therapy for patients with NHL who have poorer prognoses.

Enzymatic properties of phenylalanine101 mutant enzyme of ribonuclease rh from Rhizopus niveus

To investigate the role of Phe101, a component of a base recognition site (B2 site) of a base-nonspecific RNase Rh from Rhizopus niveus, we prepared several enzymes mutated at this position, F101W, F101L, F101I, F101A, F101Q, F101R, and F101K, and their enzymatic activities towards RNA, 16 dinucleoside phosphates, and 2', 3'-cyclic pyrimidine nucleotides were measured. Enzymatic activity toward RNA of F101W, F101L, and F101I were about 7, 20, and 3.8% of the native enzyme, respectively, and those of the other mutants were less than 1% of the RNase Rh. Similar results were also obtained with GpG as substrate. Thus, it was concluded that Phe101 is a very important residue as a component of the B2 site of RNase Rh, and its role could be replaced by Leu, then Trp and Ile, though in less effectively. The results suggested that some kind of interaction between B2 base and the side chain of amino acid residue at the 101th position, such as pi/pi or CH/pi interaction is very important for the enzymatic activity of RNase Rh. The mutation of Phe101 markedly affected the enzymatic activity toward dinucleoside phosphates and polymer substrates, but only moderately the rate of hydrolysis of cyclic nucleotides, indicating the presence of secondary effect of the mutation on B1 site.

Relationship of two ribonucleases with molecular masses of 45 kDa and 37 kDa from the culture medium of Lentinus edodes

Lentinus edodes (shiitake) produces three base non- specific and acid ribonucleases, RNase Le2, RNase Le37 and RNase Le45. The primary structures of the former two RNases, having molecular masses about 24 and 37 kDa, respectively, have been elucidated to be members of the RNase T2 family. The latter two are excreted from mycelia into the medium. In this report, we estimated the primary structure of RNase Le45 using the following experimental evidence. (i) The partial amino acid sequence of RNase Le45 determined that up to about 60% of total protein was identical with that of RNase Le37. (ii) The amino acid composition of RNase Le45 was identical to that of RNase Le37. (iii) The elution profiles on HPLC of lysylendopeptidase and Staphylococcus aureus V8 protease digests of RCM-RNase Le45 (reduced and S-carboxymethylated RNase Le45) were very similar to those of RNase Le37, except for the absence of C-terminus peptide which contained O-glycosylated peptides. However, RNase Le45 contained about 70 residues of mannose and 4 residues of hexosamine. These values were more than twice those of RNase Le37. (iv) RNase Le45 was immunologically indistinguishable from RNase Le37. (v) After treatment with both glycosidase EndoH and alpha-mannosidase, RNases Le37 and Le45 gave complex bands by slab-gel electrophoresis. However, one of the major bands with the highest mobility from RNase Le45 and Le37 showed the molecular mass of 29 kDa in common, which is slightly larger than that of RNase Le2 containing no carbohydrate. These results indicated that RNase Le45 is an enzyme which is a heavily glycosylated species of RNase Le37.

Crystal structure of a plant ribonuclease, RNase LE

Ribonuclease LE (RNase LE) from cultured tomato (Lycopersicon esculentum) cells is a member of the RNase T(2) family showing broad base specificity. The crystal structure of RNase LE has been determined at 1.65 A resolution. The structure consists of seven alpha-helices and seven beta-strands, belonging to an alpha+beta type structure. Comparison of the structure of RNase LE with that of RNase Rh, a microbial RNase belonging to the RNase T(2) family, reveals that while the overall folding topologies are similar to each other, major insertions and deletions are found at the N-terminal regions. The structural comparison, an amino acid sequence alignment of the RNase T(2) enzymes, and comparison of the disulfide-bonding pattern of these enzymes show that the structure of RNase LE shown here is the basic framework of the animal/plant subfamily of RNase T(2) enzymes (including a self-incompatibility protein called S-RNase), and the structure of RNase Rh is that of the fungal subfamily of RNase T(2) enzymes (including RNase T(2)). Subsequently, we superposed the active-site of the RNase LE with that of RNase Rh and found that (1) His39, Trp42, His92, Glu93, Lys96, and His97 of RNase LE coincided exactly with His46, Trp49, His104, Glu105, Lys108, and His109, respectively, of RNase Rh, and (2) two conserved water molecules were found at the putative P(1) sites of both enzymes. These facts suggest that plant RNase LE has a very similar hydrolysis mechanism to that of fungal RNase Rh, and almost all the RNase T(2) enzymes widely distributed in various species share a common catalytic mechanism. A cluster of hydrophobic residues was found on the active-site face of the RNase LE molecule and two large hydrophobic pockets exist. These hydrophobic pockets appear to be base binding sites mainly by hydrophobic interactions and are responsible for the base non-specificity of RNase LE.

Amino acid sequence of a nuclease (nuclease Le1) from Lentinus edodes

The fruit bodies of Lentinus edodes produce two acid nucleases, nucleases Le1 and Le3, both of which are thought to be candidates for the enzymes producing a tasty substance, 5'-GMP. To obtain the basic information on the mechanism of production of 5'-GMP, and structure-function relationship of these nucleases, the primary structure of nuclease Le1 was estimated by both protein chemistry and gene cloning. Nuclease Le1 is a glycoprotein and consists of 290 amino acid residues, and about 2 and 6 residues of hexosamine and neutral sugar, respectively. The nucleotide sequence of cDNA and genomic DNA encoding nuclease Le1 indicated the presence of 20 amino acid residues of a signal peptide. Nuclease Le1 has 115 and 108 residues of identical amino acid residues with nucleases P1 and S, respectively. The amino acid residues concerning the coordination with Zn2+ in nuclease P1 are all conserved in nuclease Le1. Nuclease Le1 contains 8 half-cystine residues and 4 of them are located at the same places as those of nucleases P1 and S.

Amino acids and peptides. LVII. Synthetic peptide with a sequence of ribonuclease from Sulfolobus solfataricus, SSR(1-62), does not function as an RNase

The 62 residue peptide, SSR(1-62), whose sequence corresponds to that of ribonuclease (RNase) from Sulfolobus solfataricus, and its related peptides, SSR(1-22) and SSR(10-62), were chemically synthesized and their RNase activity and DNA-binding activity were examined. The RNase activity assay using yeast RNA or tRNA(fMet) as substrate showed that the synthetic peptide SSR(1-62) did not hydrolyze yeast RNA or tRNA(fMet). These data were not consistent with previous reports that both the native peptide isolated from S. solfataricus [Fusi et al. (1993) Eur. J. Biochem. 211, 305-311] and the recombinant peptide expressed in Escherichia coli [Fusi et al. (1995) Gene 154, 99-103] were able to hydrolyze tRNA(fMet). However, the synthetic SSR(1-62) exhibited DNA-binding activity. In the presence of synthetic SSR(1-62), the cleavage of DNA (plasmid pUCRh2-4) by restriction endonuclease (EcoRI) was not observed, suggesting that synthetic SSR(1-62) bound to DNA protected DNA from its enzymatic digestion. Neither SSR(1-22) nor SSR(10-62) prevented DNA from being cleaved by a restriction enzyme. These findings strongly suggest the importance of not only the N-terminal region of SSR(1-62) but also the C-terminal region for DNA-binding. Circular dichroism spectroscopy of synthetic SSR(1-62) indicated a beta-sheet conformation, in contrast with synthetic SSR(1-22), which exhibited an unordered conformation.

Amino acid sequence of an unique ribonuclease with a C-terminus rich in O-glycosylated serine and threonine from culture medium of Lentinus edodes

The mushroom Lentinus edodes produces three base-non-specific and acid ribonucleases, RNases Le2, Le37, and Le45. The latter two are excreted from mycelia into the medium. The primary structure of RNase Le37, which had a molecular mass of 37 kDa, was sequenced. It was a member of the RNase T2 family, as is RNase Le2. RNase Le37 was some 30 amino acid residues longer at the C-terminal end than RNase Le2. The C-terminal region of RNase LE37 was rich in O-glycosylated serine and threonine. In fungal glucoamylases and chitinases, which hydrolyze raw-starch and chitin, respectively, have structures resembling the structure of the C-terminal of RNase Le37.

Preoperative concurrent chemoradiotherapy plus radical surgery for advanced squamous cell carcinoma of the oral cavity: an analysis of long-term results

Locoregionally advanced squamous cell carcinomas of the head and neck continue to be a major clinical problem. We demonstrated in 1996 that preoperative concurrent cisplatin- or carboplatin-based chemotherapy and radiotherapy plus radical surgery in advanced oral cancer had minimal toxicity, had high clinical tumor response rates, was well tolerated and produced impressive complete response rates and a high 5-year survival rate. The purpose of the present study was the long-term follow-up of this treatment regimen for advanced oral carcinoma. Forty-eight patients with squamous cell carcinoma of the oral cavity (including soft palate) were treated preoperatively with cisplatin- or carboplatin-based chemotherapy in combination with simultaneous irradiation to a target volume of 40 Gy, and 2-6 weeks later underwent curative surgery. All patients with advanced Stage II (n=7), Stage III (n=22) and Stage IV (n=19) were treated and followed for an average of 7.2 years (range: 61-144 months). The overall actuarial survival of all patients was 81.3% at 5 years and also at 10 years. Progression-free survival at both 5 and 10 years was 84.8% for all patients, and 85.7% for Stage II, 90.0% for Stage III, and 78.9% for Stage IV patients. Progression-free survival rates according to the histopathologic regression grade of primary tumor following preoperative chemoradiotherapy at 10 years were 40. 0% for Grade IIa, 88.9% for Grade IIb, 100% for Grade III, and 87.5% for Grade IV. Patients who achieved good responses histopathologically (Grades IIb, III, IV) had superior survival rates in comparison to patients with extensive residual tumor (Grade IIa) in surgically resected specimens (p=0.0012). A better histologic regression grade was also associated with a higher survival rate even in the long-term analysis. This treatment regimen for advanced oral cancer produced high clinical and pathologic complete response and survival rates with an acceptable acute toxicity profile and lack of late therapeutic complications. The long-term follow-up showed gratifying results even for advanced oral cancers without a substantial increase in distant metastasis and second primary malignancy.

Amino acids and peptides. LV. Application of 2-adamantyl derivatives as protecting groups to the synthesis of peptide fragments related to Sulfolobus solifataricus ribonuclease. II

Segment condensations were performed to construct peptide fragments related to Sulfolobus solifataricus Ribonuclease. At each condensation step, the new protecting groups were stable. The protected peptide fragments were treated with a low-high HF procedure to give the desired peptide fragments. These peptide fragments were also prepared by the solid-phase method, and the obtained peptides were compared with those obtained by the solution method. The peptide fragments obtained by the solution method were identical with those obtained by the solid-phase method on analytical HPLC, indicating that the new protecting groups could be easily removed by HF, and no racemization occurred during the synthesis of the protected peptides.

Amino acids and peptides. LIV. Application of 2-adamantyl derivatives as protecting groups to the synthesis of peptide fragments related to Sulfolobus solifataricus ribonuclease. I

The 2-adamantyloxycarbonyl group was employed for the protection of the epsilon-amino group of Lys and the hydroxyl group of Tyr, and the 2-adamantyl ester was employed for the protection of the beta-carboxyl group of Asp in order to construct eight peptide segments as building blocks for the preparation of peptide fragments related to the sequence of Sulfolobus solifataricus Ribonuclease. The usefulness of the above protecting groups developed in our laboratory was confirmed.

[Optimization of pulse sequences for MR cholangiopancreatography with FASE]

Various types of pulse sequences for MR cholangiopancreatography (MRCP) have been developed in the past ten years. FASE (fast advanced spin echo) is one of the single-shot fast spin-echo sequences developed by Toshiba. By using this sequence, 2D single slice, 2D multiple slice and 3D methods can be provided. We routinely employ 2D single slice and 3D methods. The merit of 2D single slice method is conveniently obtained projection imaging within short data acquisition time. On the other hand, 3D method can yield detailed evaluation of various anatomical structures and abnormalities by using thin-slice source images. O2-inhalation study is especially recommended in case of 3D method. With the proper knowledge of sequence characteristics, MRCP using FASE can provide valuable informations of pancreatico-biliary diseases.

[Elimination of artifacts in MRCP: technical consideration]

Artifacts of MR cholangiopancreatography (MRCP) include fluid-filled gastrointestinal tracts, respiratory motion artifacts, spasm of Oddi's sphincter, vascular compression of bile ducts, overlapping of various anatomical structures and bright signal of surrounding fatty tissue. In this article, various technical considerations to eliminate these artifacts were described for the better imaging analysis of MRCP. The use of high-concentration ferric ammonium citrate (Ferriseltz) is recommended to reduce bright signal of fluid-filled gastrointestinal tracts. In case of long breathhold sequences, O2-inhalation study is useful to eliminate respiratory motion artifacts. Careful attention should be paid to the spasm of Oddi's sphincter and the vascular compression of bile ducts to avoid erroneous interpretation of MRCP findings.

[Basic principles and historical consideration of MR cholangiopancreatography]

Basic principle of MR cholangiopancreatography (MRCP) is heavily T2-weighted imaging (hydrography) to use bile and pancreatic juice as "natural contrast medium". Firstly developed sequence for MRCP was a CE-FAST sequence, which employed time-reversed FID signal. The current most popular sequences for MRCP are single-shot fast spin-echo sequences, which are divided into three types (2D single slice, 2D mutiple slice and 3D methods). The advantage of 2D single slice method is conveniently obtained projection imaging within a few seconds of examination time. Both 2D multiple slice and 3D methods consists of a MIP image and a series of source images. The MIP image creates global images of pancreatico-biliary system. The source images provide detailed evaluation of various anatomical structures and abnormalities. By using these sequences properly, MRCP can yield valuable informations of pancreatico-biliary diseases non-invasively.

Characterization and primary structure of a base non-specific and acid ribonuclease from Dictyostelium discoideum

A base non-specific and acid RNase was isolated from cellular slime mold (Dictyostelium discoideum) cells in a homogeneous state (about 2.4 kDa) by SDS-polyacrylamide gel electrophoresis. The RNase (RNase DdI) has a pH optimum of 5.0. The amino acid sequence of RNase DdI was determined by a combination of protein chemistry, a search of Data base, Dicty cDB and further sequence analysis of cDNA from the same bank. RNase DdI consists of 198 amino acid residues, and about 13.3, 0.9, 1.2, 3.3, and 1.0 residues of mannose, xylose, glucose, GlcNAc, and GalNAc, respectively. RNase DdI has two characteristic conserved segments of the RNase T2 family, and thus belongs to the RNase T2 family. Considering the fact that most of the RNase activity of D. discoideum is present in the lysosomal fraction [Wiener and Ashworth (1970) Biochem. J. 118, 505-512], it was concluded that the lysosomal RNase in D. discoideum is a member of the RNase T2 family. The amino acid sequence of RNase DdI is highly homologous with that of Physarum polycephalum RNase (RNase Phyb), and its amino acid sequence seems to be similar to those of plant/animal type RNases, rather than fungal RNases. The location of RNase DdI in the phylogenetic tree of the RNase T2 family was estimated.

A protease sensitive region of plant and animal ribonucleases belonging to the RNase T2 family

Recombinant RNase LE from tomato and squid liver RNase Tp, typical plant/animal type RNases belonging to the RNase T2 family, were subjected to limited digestion with several proteases, and the cleavage sites were analyzed by Edman degradation. Recombinant RNase LE was cleaved specifically at the 24th Lys by lysylendopeptidase and trypsin, and RNase Tp was cleaved at the 21st Glu by V8 protease. These cleavage sites are located very close to those where the cleavage during preparation of several animal RNase T2 family enzymes was observed. From this finding, it was concluded that the short segment around the 20th amino acid residue in plant/animal RNases is located on the surface of the molecules and forms loops, and is thus very sensitive to proteases.

Primary structure of porcine spleen ribonuclease: sequence homology

The primary structure of porcine spleen RNase (RNase Psp1) was investigated as a mean of assessing the structure-function relationship of base non-specific ribonucleases of animal origin. N-terminal analysis of RNase Psp1 yielded three N-terminal sequences. These peptides were separated by gel-filtration on Superdex 75HR, after reduction and S-carboxymethylation of RNase Psp1. Determination of the amino-acid sequence of these peptides indicated that the RNase Psp1 preparation consisted of three peptides having 20 (RCM RNase Psp1 pep1), 15 (RCM RNase Psp1 pep2), and 164 (RCM RNase Psp1 pro) amino-acid residues, respectively. It possessed two unique segments containing most of the active site amino-acid residues of the RNases of the RNase T2 family. The alignment of these three peptides in RNase Psp1 was determined by comparison with the other enzymes in the RNase T2 family. The overall results showed that RCM RNase Psp1 pep1 and RCM RNase Psp1 pep2 are derived from the N-terminal and C-terminal regions of RNase Psp1, respectively, probably by processing by some protease. The molecular mass of the protein moiety of RNase Psp1 was 23235 Da.

Primary structure of a squid acid and base non-specific ribonuclease

Squid (Todarodes pacificus) liver RNase (RNase Tp) was purified. RNase Tp was a base non-specific and acid RNase. Upon hydrolysis of RNA, RNase Tp released four mononucleotides in the order of G > A > U > C. RNase Tp consisted of two peptides with 198 and 23 amino acid residues. The amino acid sequences of these peptides were analyzed. The large peptide had two unique segments containing most of the active site amino acid residues of RNase T2 family enzymes. From the comparison of the sequence of short peptide with the sequences of the other RNase belonging to RNase T2 family RNases, it was found that the amino acid sequence of the short peptide was very similar to that of the C-terminal portion of RNases of the RNase T2 family. Thus, we concluded that the short peptide was a C-terminal part of RNase Tp. The molecular mass of the protein moiety of RNase Tp was 25,582 daltons. The amino acid sequence of RNase Tp most resembles that of oyster RNase (91 amino acid residues identical) in the RNase T2 family RNases. However, the N-terminal portion of RNase Tp was unusually similar to those of plant RNases, rather than the other animal RNases.

Primary structure of porcine spleen ribonuclease: sequence homology

The primary structure of porcine spleen RNase (RNase Psp1) was investigated as a mean of assessing the structure-function relationship of base non-specific ribonucleases of animal origin. N-terminal analysis of RNase Psp1 yielded three N-terminal sequences. These peptides were separated by gel-filtration on Superdex 75HR, after reduction and S-carboxymethylation of RNase Psp1. Determination of the amino-acid sequence of these peptides indicated that the RNase Psp1 preparation consisted of three peptides having 20 (RCM RNase Psp1 pep1), 15 (RCM RNase Psp1 pep2), and 164 (RCM RNase Psp1 pro) amino-acid residues, respectively. It possessed two unique segments containing most of the active site amino-acid residues of the RNases of the RNase T2 family. The alignment of these three peptides in RNase Psp1 was determined by comparison with the other enzymes in the RNase T2 family. The overall results showed that RCM RNase Psp1 pep1 and RCM RNase Psp1 pep2 are derived from the N-terminal and C-terminal regions of RNase Psp1, respectively, probably by processing by some protease. The molecular mass of the protein moiety of RNase Psp1 was 23235 Da.

Enzymatic properties of double mutant enzymes at Asp51 and Trp49 and Asp51 and Tyr57 of RNase Rh from Rhizopus niveus

Mutation of Asp51 of a base-nonspecific RNase, RNase Rh, to Ser, Thr, or Gln makes the enzyme more preferential for the dinucleoside phosphate (XpY) having G and C at the 5'-side (X). On the other hand the mutation of one of the B1 site components, Tyr57 to Trp, and Trp49 to Phe makes the enzyme more preferential for purine bases and pyrimidine bases, respectively. In this study, to obtain more specific RNases and RNases with different base specificity, we prepared double-mutant enzymes that have Ser, Thr, and Asn at the 51st position and Trp at the 57th position or Phe at the 49th position, and their enzymatic specificities were studied with XpYs as substrates. The double-mutant enzymes D51SY57W and D51TY57W are more guanylic acid preferential than the mother single-mutant enzymes, D51S and D51T, respectively. They are extremely guanylic preferential RNases. D51NY57W is more a guanylic acid preferential enzyme than D51N, but cytidylic acid preference is of a similar order to that of D51N. The double mutant enzymes D51NW49F and D51TW49F showed an increased cytidylic acid preference as well as guanylic acid preference as compared to the mother single-mutant enzymes, D51T and D51N. The results of analysis of base specificity by the release of mononucleotides from RNA and the rates of hydrolysis of homopolynucleotides led to the same conclusion as in the case of the hydrolysis of XpY.

Primary structure of base non-specific and acid ribonuclease from bullfrog (Rana catesbeiana)

A base non-specific acid ribonuclease (RNase RCL2) was purified from bullfrog liver [H. Yagi et al. Biol. Pharm. Bull., 18, 219-222 (1992)]. The sequence study and comparison of the amino acid sequence of the enzyme with homologous RNases from oyster, drosophila and chicken liver suggested that the RNase RCL2 consisted of two components, large protein fraction (182 amino acid residues) and peptide 2 (20 amino acid residues) or peptide 1 (18 amino acid residues), and that both components bind with disulfide bridge. The RNase preparation was probably formed from a single polypeptide protein by processing with some proteases. The amino acid sequence of RNase RCL2 showed that the RNase belongs to the RNase of RNase T2 family and its sequence most resembles chicken liver acid RNase. In RNase RCL2, the amino acid residues which consist of the active site and major base recognition site of RNase Rh, a typical RNase of RNase T2 family, are very well conserved except for Tyr57 (RNase Rh numbering), and part of the amino acid residues of the minor base recognition site (Phe101 and Pro92) are also conserved.

[A case of spinal hemorrhage associated with abdominal aortic coarctation]

We report a 59-year-old male with abdominal aortic coarctation presented as paraplegia due to spinal hemorrhage caused by the rupture of abnormally dilated spinal artery. In coarctation of aorta, coarctation is usually located in the aortic isthmus which could be the cause of cervical and upper thoracic myelopathy. However, there has been no report of abdominal aortic coarctation with hemorrhagic transverse myelopathy. In this case hemorrhage occurred after surgical treatment and prescribed warfarin may have exaggerated the outcome.

Role of histidine 46 in the hydrolysis and the reverse transphosphorylation reaction of RNase Rh from Rhizopus niveus

In order to study the reaction mechanism of RNase Rh from Rhizopus niveus, the rates of cleavage of four 2',3'-cyclic nucleotides by mutant enzymes of RNase Rh, H46F, H109F, E105Q, and K108L were measured. H46F is virtually inactive towards cyclic nucleotides, but H109F hydrolyzed these substrates at 0.7-4.5% of the rates of the native RNase Rh. The other mutants hydrolyzed 2',3'-cyclic nucleotides at 15-20% of the rates of the native enzyme. Relative enzymatic activities towards four cyclic nucleotides of H109F in the hydrolysis reaction (2nd step) were much higher than in the transphosphorylation reaction (the 1st step). In the presence of a 13-fold excess of uridine, H109F catalyzed the transphosphorylation reaction of 2',3'-cyclic AMP (A>p) to ApU. However, this reaction was not catalyzed by H46F mutant or native RNase Rh. These results showed that His46 is crucial to the hydrolysis reaction, and to the reversed reaction of the transphosphorylation reaction. We suggest that His46 in RNase Rh plays a major role in these reactions by acting as a base catalyst to activate water and the 5'-hydroxyl group of nucleosides, respectively.

The base specificities of tomato ribonuclease (RNase LE) and its Asp44 mutant enzyme expressed from yeast cells

RNase LE from cultured tomato cells is a member of the RNase T2 family. It is, however, distinguishable from RNase Rh from Rhizopus niveus, a typical RNase of the RNase T2 family, by its CD spectrum in the 200-250 nm region. In order to reinvestigate the base specificity of RNase LE and to study the role of Asn44 in RNase LE, which is considered to correspond to the base recognition site Asp51 of RNase Rh, RNase LE, and its Asp mutant at the 44th position were expressed from yeast cells with the same expression system as RNase Rh [K. Ohgi, et al., J. Biochem., 109, 776-785 (1991)]. RNase LE with four extra amino acid residues at the 2nd amino acid residue of mature RNase LE and its Asp44 mutant were secreted from yeast cells to give a yield of 10 mg/liter and 0.5 mg/liter culture broth, respectively. The expressed RNase LE (RNase RNAP LE) had the same characteristics as native RNase LE in the CD spectrum and specific activity. This is the first example of the expression of plant RNase from microbes and in sufficient amount to perform further enzymological research. The base specificity of RNase LE was guanylic acid preferential and that of N44D was changed to a more adenylic acid preference as compared to that of RNase LE. These experiments showed that Asn44 of RNase LE is crucial for base recognition as the case of Asp51 in RNASE Rh, and also suggested that the base recognition mechanism of RNase LE is very similar to that of RNase Rh.

Preoperative simultaneous cisplatin- or carboplatin-based chemotherapy and radiotherapy for squamous cell carcinoma of the oral cavity

BACKGROUND

Encouraging results have been reported with cisplatin- or carboplatin-based chemotherapy regimens and simultaneous irradiation treatment in advanced and unresectable head and neck head and neck cancer. We have therefore examined the effectiveness of such therapy on tumor control, survival, and toxicity in patients with advanced oral squamous cell carcinoma.

METHODS

Forty-one patients with squamous cell carcinoma of the oral cavity (including soft palate) were treated preoperatively with cisplatin or carboplatin, and 5-fluorouracil or peplomycin in combination with simultaneous irradiation to a target volume of 40Gy, and 2-6 weeks later, curative surgery was performed.

RESULTS

Thirty-eight patients (91.7%) had Stage III or IV disease, and three patients had Stage II lesions. The preoperative clinical responses of the primary tumor were: 25 patients (61.0%) achieved a complete response (CR), 15 (36.6%) a partial response (PR), only 1 patient (2.4%) had stable disease or no change (NC). The overall response rate was 97.6%. Histological effects according to the grading system of Shimosato and coworkers [Jpn J Clin Oncol 1:19-35, 1971] were seen in 38/41 (92.7%). Of clinical CR patients, 73.9% were also histologic negative for tumor. Side effects of this therapy were relatively low and reversible. With a median follow-up of 52.8 months (range 17-92 months), 5-year cumulative survival rates were 81.5% for all patients, 100% for Stage II, 88.6% for Stage III, and 76.4% for Stage IV patients, respectively. There was no significant postoperative morbidity.

CONCLUSIONS

This preoperative chemoradiotherapy regimen was highly active, well tolerated, and appeared to have a survival benefit even for advanced carcinomas of the oral cavity.