Chemo-enzymatic synthesis of a bioactive peptide containing a glutamine-linked oligosaccharide and its characterization

A bioactive peptide containing a glutamine-linked oligosaccharide was chemo-enzymatically synthesized by use of the solid-phase method of peptide synthesis and the transglycosylation activity of endo-beta-N-acetylglucosaminidase. Substance P, a neuropeptide, is an undecapeptide containing two L-glutamine residues. A substance P derivative with an N-acetyl-D-glucosamine residue attached to the fifth or sixth L-glutamine residue from the N-terminal region was chemically synthesized. A sialo complex-type oligosaccharide derived from a glycopeptide of hen egg yolk was added to the N-acetyl-D-glucosamine moiety of the substance P derivative using the transglycosylation activity of endo-beta-N-acetylglucosaminidase from Mucor hiemalis, and a substance P derivative with a sialo complex-type oligosaccharide attached to the L-glutamine residue was synthesized. This glycosylated substance P was biologically active, although the activity was rather low, and stable against peptidase digestion. The oligosaccharide moiety attached to the L-glutamine residue of the peptide was not liberated by peptide-N(4)-(N-acetyl-beta-D-glucosaminyl) asparagine amidase F.

Molecular cloning of cDNA encoding alpha-N-acetylgalactosaminidase from Acremonium sp. and its expression in yeast

Alpha-N-acetylgalactosaminidase (alpha-GalNAc-ase; EC 3.2.1.49) is an exoglycosidase specific for the hydrolysis of terminal alpha-linked N-acetylgalactosamine in various sugar chains. The cDNA, nagA, encoding alpha-GalNAc-ase from Acremonium sp. was cloned, sequenced, and expressed in yeast Saccharomyces cerevisiae. The nagA contains an open reading frame which encodes for 547 amino acid residues including 21 residues of a signal peptide in its N-terminal. The calculated molecular mass of mature protein from the deduced amino acid sequence of nagA is 57260 Da, which corresponds to the value obtained from SDS-PAGE of native and recombinant enzymes treated with endo-beta-N-acetylglucosaminidase H. The amino acid sequence of NagA showed significant similarity to those of eukaryotic alpha-GalNAc-ases and alpha-galactosidases (alpha-Gal-ases), particularly alpha-Gal-ase A (AglA) from Aspergillus niger. Phylogenetic analysis revealed that NagA does not belong to the cluster of vertebrate alpha-GalNAc-ase and alpha-Gal-ase but forms another cluster with AglA and yeast alpha-Gal-ases. Thus, the evolutionary origin of the fungal alpha-GalNAc-ase is suggested to be different from that of vertebrate alpha-GalNAc-ase. This is the first report of a microbial alpha-GalNAc-ase gene.

Mitral valve plasty for mitral regurgitation after blunt chest trauma

A 21 year-old woman was admitted to our hospital because of chest and back pain after blunt chest trauma. On admission, consciousness was clear and a physical examination showed labored breathing. Her vital signs were stable, but her breathing gradually worsened, and artificial respiration was started. The chest roentgenogram and a subsequent chest computed tomographic scans revealed contusions, hemothorax of the left lung and multiple rib fractures. A transthoracic echocardiography (TTE) revealed normal left ventricular wall motion and mild mitral regurgitation (MR). TTE was carried out repeatedly, and revealed gradually progressive MR and prolapse of the posterior medial leaflet, although there was no congestive heart failure. After her general condition had recovered, surgery was performed. Intraoperative transesophageal echocardiography (TEE) revealed torn chordae at the posterior medial leaflet. The leaflet where the chorda was torn was cut and plicated, and posterior mitral annuloplasty was performed using a prosthetic ring. One month later following discharge, the MR had disappeared on TTE.

Proteolytic Activation of SREBPs during Adipocyte Differentiation

A member of sterol regulatory element-binding protein (SREBP) family, SREBP-1, is a key regulator of adipocyte differentiation. Expression of the SREBP-1 gene is induced during adipocyte differentiation, but proteolytic activation of the synthesized precursor form of SREBP-1 has not been well analyzed. The proteolytic processing of SREBPs is severely suppressed in sterol loaded culture cells. Here we report that a splicing isoform, SREBP-1a, is predominantly expressed in 3T3-L1 preadipocytes and adipocytes, and that the nuclear active form of SREBP-1 protein increases in adipocyte differentiation. We further show that the amount of nuclear SREBP-2 protein also increases despite no increase in SREBP-2 mRNA, suggesting that proteolytic cleavage of SREBPs is induced in lipid loaded adipocytes. Northern blot analyses reveal that mRNA levels for SREBP cleavage-activating protein (SCAP), Site-1 protease (S1P), and Site-2 protease (S2P), which participate in the proteolytic processing of SREBPs, are relatively unaffected in adipogenesis. These results demonstrate that SREBP-2 appears to promote adipocyte differentiation as well as SREBP-1 and that the proteolytic activation of SREBPs may be induced by an as-yet unidentified mechanism in lipid loaded adipocytes.

Apoptotic epithelial cells in biopsy specimens from infants with streaked rectal bleeding

BACKGROUND

Histologic studies of rectosigmoidal mucosal biopsies of infants with isolated blood-streaked stool have shown many eosinophils and revealed aggregates of small dark granules (nuclear dust). However, no description of the nuclear dust has been made for this condition and the nature of the nuclear dust has not been thoroughly investigated. We determined the characteristics of these particles in biopsies from infants with streaked rectal bleeding.

METHODS

Nineteen infants who were younger than 6 months old and had isolated rectal bleeding were studied, as were six age-matched control infants. Rectosigmoidal mucosal biopsies were immunohistochemically assessed using anticarcinoembryonic antigen and macrophage-associated antibodies and examined for apoptotic cells by modified in situ TdT-mediated dUTP-biotin nick-end labelling. The number of apoptotic epithelial cells was compared between rectal bleeding and control groups.

RESULTS

Immunohistochemistry showed that at least some of the nuclear dust consisted of apoptotic epithelial cells. Infants with rectal bleeding also showed nodular lymphoid hyperplasia (n = 16), abundant eosinophils (>20/high power field, n = 14) in the mucosa, and a significantly high number of apoptotic epithelial cells relative to the control group. Rectal bleeding disappeared at 6-month follow-up in 14 of 18 infants (one was lost to follow-up) who were fed a different milk formula or breast-fed (their mothers were restricted from having cow's milk and eggs).

CONCLUSIONS

The high number of apoptotic epithelial cells in rectosigmoidal mucosal biopsies of infants with streaked rectal bleeding is probably caused by accelerated epithelial cell turnover and apoptosis.

Brain perfusion measured by flow-sensitive alternating inversion recovery (FAIR) and dynamic susceptibility contrast-enhanced magnetic resonance imaging: comparison with nuclear medicine technique

The aim of this study was to compare cerebral perfusion images and regional cerebral blood flow (rCBF) of SPECT study with the images and regional intensity of relative cerebral blood flow (CBF) images acquired by contrast-enhanced perfusion MR imaging (pMRI) and flow-sensitive alternating inversion recovery (FAIR). Twelve patients with various cerebral diseases were underwent I-123-IMP SPECT, pMRI, and FAIR studies to measure rCBF. A total of 12 regions of interest (ROI) were created over cerebrum and cerebellum to acquire the corresponding rCBF from I-123-IMP study and regional average signal intensity from CBF images of pMRI and FAIR studies. Left-to-right (L/R) and cerebral-to-cerebellar (CCR) ratios were created from the rCBF of I-123-IMP and signal intensity of CBF images of pMRI and FAIR. Image quality of FAIR was the poorest among all; however, CBF images of pMRI and FAIR images show comparatively decreased intensity at the corresponding site of decreased perfusion on I-123-IMP images. Both FAIR and pMRI images showed high intensity along the sinuses, choroid plexus, and large vessels in sulci. No significant correlation was found among all imaging modalities. But L/R ratio of I-123-IMP showed significant correlation with those of pMRI and FAIR, but for CCR, significant correlation was observed only between I-123-IMP and FAIR. Perfusion images of both pMRI and FAIR may produce images comparable to SPECT study. But to calculate absolute CBF more easy-to-apply and accurate algorithms are needed to overcome the artifacts from large vessels.

Simultaneous display of MRA and MPR in detecting vascular compression for trigeminal neuralgia or hemifacial spasm: comparison with oblique sagittal views of MRI

A new technique, simultaneous display of magnetic resonance angiography (MRA) and multiplanar reconstruction (MPR), was performed by a workstation to identify the involved vessels in patients with trigeminal neuralgia (TN) or hemifacial spasm (HFS), and the results were compared with those of oblique sagittal MRI technique. Twelve patients with either HFS or TN were prospectively assessed by simultaneous display of MRA and MPR, and oblique sagittal techniques, to point out the neurovascular compression and to identify the involved vessels. Three-dimensional (3D) time-of-flight (TOF) spoiled gradient-echo (SPGR) images were acquired to create MRA and MPR. Oblique sagittal views were also created and displayed on films. A total of 15 vessels in 12 patients were identified as compressing vessels during surgery. Simultaneous display of MRA and MPR technique pointed out the presence of vessels at and/or around root entry/exit zone (REZ) in all 12 patients, but proper identification by the name of the individual vessel was correct in 13 of 15 cases. However, oblique sagittal technique indicated the presence of vessels at and/or around REZ in 11 patients, but only 8 of 14 vessels were correctly identified. Our new method, simultaneous display of MRA-MPR, facilitated correct identification of the involved vessels compared with the oblique sagittal view method.

Microbial production of amino acids in Japan

The microbial biotechnology of amino acids production which was developed and industrialized in Japan have been summarized. The amino acids include L-glutamic acid, L-lysine, L-threonine, L-aspartic acid, L-alanine, L-cysteine, L-dihydroxyphenylalanine, D-p-hydroxyphenyl-glycine, and hydroxy-L-proline.

Enzymatic syntheses of T antigen-containing glycolipid mimicry using the transglycosylation activity of endo-alpha-N-acetylgalactosaminidase

Thomsen-Friedenreich antigen (T antigen) disaccharide, beta-D-galactose-(1-->3)-alpha-N-acetyl-D-galactosamine (beta-D-Gal-(1-->3)-alpha-D-GalNAc), containing glycolipid mimicry was synthesized using the transglycosylation activity of endo-alpha-N-acetylgalactosaminidase from Bacillus sp. This enzyme could transfer the disaccharide from a p-nitrophenyl substrate to water-soluble 1-alkanols and other alcohols at a transfer ratio of 70% or more. Although the transfer ratios were lower for water-insoluble than water-soluble alcohols, they were shown to increase by adding sodium cholate to the reaction mixtures. The enzyme also transferred the disaccharide directly from asialofetuin to 1-alkanols. The anomeric bond between the disaccharide and 1-alkanols of the transglycosylation product is in the alpha configuration as determined by sequential digestion of jack bean beta-galactosidase and Acremonium alpha-N-acetylgalactosaminidase. Since the transglycosylation product, beta-D-Gal-(1-->3)-alpha-D-GalNAc-(1-->O)-hexyl, efficiently inhibits the binding of anti-T antigen monoclonal antibody to asialofetuin, it has potential as an agent for blocking T antigen-mediated cancer metastasis.

Aminopeptidases A, B, and N and dipeptidase D are the four cysteinylglycinases of Escherichia coli K-12

Aminopeptidases A, B, and N and dipeptidase D, with broad substrate specificity, are the four cysteinylglycinases of Escherichia coli K-12, and there is no peptidase specific for the cleavage of cysteinylglycine.

Collecting duct carcinoma mixed with common renal cell carcinoma: analysis of morphological characteristics using lectin histochemistry

Recently, cases of collecting duct carcinoma have been reported which were thought to have arisen from the renal collecting ducts or distal tubuli. We present here a rare case of collecting duct carcinoma mixed with common (conventional) renal cell carcinoma. A 51-year-old man underwent right nephrectomy under the diagnosis of renal tumor. Histochemically, markers for the collecting ducts/distal tubuli, such as peanut agglutinin (PNA) and soybean agglutinin (SBA), were identified in the collecting duct carcinoma as well as on several luminar surfaces of the common renal cell carcinoma. Based on the results of histological, histochemical and chromosomal examinations, we speculated on the histogenesis of this collecting duct carcinoma.

Synthesis and Biological Evaluation of Cytogenin Derivatives

To enhance the stability in vivo, new derivatives of cytogenin were synthesized, and their biological activity and stability in mice were estimated. 2-(8-Hydroxy-6-methoxy-1-oxo-1H-2-benzopyran-3-yl)propionic acid (NM-3) was found to be the most stable among them. It modified collagen-induced arthritis in mice. It also showed potent anti-angiogenic activity in a mouse dorsal air sac assay.

A novel low-density lipoprotein receptor-related protein mediating cellular uptake of apolipoprotein E-enriched beta-VLDL in vitro

We report here the identification of a novel member of the low-density lipoprotein receptor (the LDL receptor) family through signal sequence trap screening of a mouse lymphocyte cDNA library. The protein was termed LDL receptor-related protein 9 (LRP9). LRP9 is a type I membrane protein predicted to contain 696 amino acids with a calculated molecular mass of 74 764 Da. The NH(2)-terminal half of LRP9 contains two CUB domains separated by a single ligand-binding repeat. The second CUB domain is followed by a cluster of three additional ligand-binding repeats and a transmembrane domain. The COOH-terminal intracellular region contains a proline-rich region. LRP9 mRNA was expressed in the liver, kidney, lung, and heart at high levels, and in the spleen and brain at low levels. In situ hybridization analysis of mouse liver, kidney, and brain detected LRP9 transcripts in hepatocytes, sinusoidal lining cells, peritubular capillaries, choroid plexus, ependyma of the third ventricle, pia matter, and hippocampus. In particular, high levels of expression were observed in the vascular walls. Apolipoprotein E (apoE)-enriched beta-VLDL stimulated cellular cholesteryl ester formation in ldl-A7/LRP9. These results raise the possibility that this newly identified receptor, which is expressed in the liver, may play a physiological role in the uptake of apoE-containing lipoproteins.

Cloning and random mutagenesis of the Erwinia herbicola tyrR gene for high-level expression of tyrosine phenol-lyase

Tyrosine phenol-lyase (Tpl), which can synthesize 3, 4-dihydroxyphenylalanine from pyruvate, ammonia, and catechol, is a tyrosine-inducible enzyme. Previous studies demonstrated that the tpl promoter of Erwinia herbicola is activated by the TyrR protein of Escherichia coli. In an attempt to create a high-Tpl-expressing strain, we cloned the tyrR gene of E. herbicola and then randomly mutagenized it. Mutant TyrR proteins with enhanced ability to activate tpl were screened for by use of the lac reporter system in E. coli. The most increased transcription of tpl was observed for the strain with the mutant tyrR allele involving amino acid substitutions of alanine, cysteine, and glycine for valine-67, tyrosine-72, and glutamate-201, respectively. A tyrR-deficient derivative of E. herbicola was constructed and transformed with a plasmid carrying the mutant tyrR allele (V67A Y72C E201G substitutions). The resultant strain expressed Tpl without the addition of tyrosine to the medium and produced as much of it as was produced by the wild-type strain grown under tyrosine-induced conditions. The regulatory properties of the mutant TyrR(V67A), TyrR(Y72C), TyrR(E201G), and TyrR(V67A Y72C E201G) proteins were examined in vivo. Interestingly, as opposed to the wild-type TyrR protein, the mutant TyrR(V67A) protein had a repressive effect on the tyrP promoter in the presence of phenylalanine as the coeffector.

Focal nodular hyperplasia of the liver: direct evidence of circulatory disturbances

Focal nodular hyperplasia of the liver is a lesion characterized by a well-circumscribed region of hyperplastic liver parenchyma and contains a stellate fibrous scar. The lesion is thought to be because of liver-cell hyperplasia that is caused by focal circulatory disturbances. We describe here a pediatric case of this lesion that provided direct histopathologic evidence of circulatory disturbances. We identified arterial and portal thrombi, as well as recanalization of arteries in the nodule. Hepatic necrosis was also seen in the lesion. We speculate that thrombosis of the hepatic artery and/or portal vein was the cause of hepatic necrosis and that reperfusion following hepatic arterial recanalization resulted in nodule formation. Although there was no stellate scar present in our case, the presence of bile ductular proliferation at the periphery of the nodule was helpful in distinguishing this lesion from adenoma and hepatocellular carcinoma. The early stage of nodular formation may explain the lack of a stellate scar in our case. The patient was treated earlier with actinomycin D and vincristine following surgical excision of Wilms' tumor. It is possible that such chemotherapy contributed to thrombosis in our case.

[An autopsy case of pulmonary mucormycosis with fatal hemoptysis from a rupture of the thoracic descending aorta during remission from acute myelocytic leukemia]

A 16-year-old girl was hospitalized because of anemia and thrombocytopenia in April 1998, and was diagnosed as having AML (FAB:M2). After failure of initial remission induction therapy, she was successfully treated with the MEC regimen as a second-line chemotherapy. On June 22, the first consolidation therapy was started. One week later, the patient developed a high fever with backache. Chest computed tomography (CT) on July 8 showed a 3cm mass lesion adjacent to the thoracic descending aorta in the left upper lobe. She was given fluconazole and antibiotics, and remained in remission. On July 24, the mass lesion changed to a cavitary lesion on chest CT, suggesting a fungal infection, probably aspergillosis. With recovery from neutropenia, the patient became asymptomatic, and fluconazole was changed to itraconazole. On July 27, she suffered sudden, massive hemoptysis and died. Autopsy revealed a localized adhesion between the cavitary lesion and the thoracic descending aorta, and the aortic wall was ruptured at this site. Microscopic examination revealed invasion of mucormycotic hyphae into the wall of the aorta with infiltration of inflammatory cells. The vasa vasorum were occluded by thrombi, in which mucormycotic hyphae were detected.

Suppression of type II collagen-induced arthritis by a new isocoumarin, NM-3

The anti-arthritic effect of NM-3, a new isocoumarin, was examined using a type II collagen-induced arthritis model for human rheumatoid arthritis in DBA/1J mice. NM-3 by oral administration suppressed dose-dependently (2-20 mg/kg/day) not only macroscopic changes such as erythema and swelling of limbs but also histopathologic changes and radiographic changes such as bone lesions. The efficacy of NM-3 was greater than those of disease-modifying anti-rheumatoid drugs (DMARDs), auranofin (40 mg/kg/day) and bucillamine (10 mg/kg/day). NM-3 failed to suppress carageenan-induced edema and to inhibit the activities of inflammation-related enzymes including cyclooxygenase-1 and -2, 5-lipoxygenase and phospholipase A2, suggesting that the mode of anti-arthritic action of NM-3 may be different from those of non-steroidal anti-inflammatory agents (NSAIDs). Since NM-3 inhibits angiogenesis in a mouse dorsal air-sac model, the observed anti-arthritic effect of NM-3 might be partly attributed to the antiangiogenic activity. Thus, NM-3 is a potential orally active therapeutic agent for the treatment of human rheumatoid arthritis.

Three types of putative presympathetic neurons in the rostral ventrolateral medulla studied with rat brainstem-spinal cord preparation

To study the electrophysiological properties of presympathetic neurons in the rostral ventrolateral medulla (RVLM), intracellular recordings were performed by the whole-cell patch-clamp technique. We utilized the neonatal rat brainstem-spinal cord preparation, in which the sympathetic neuronal network is thought to be preserved, unlike in slice preparation. In response to stimulation in the ipsilateral Th2 spinal segment including intermediolateral cell column (IML), 33 of 151 non-respiratory RVLM neurons showed antidromic action potentials with a constant latency of 45 ms, and can be considered as presympathetic neurons. We classified and characterized the RVLM presympathetic neurons into three types: 'regularly firing neurons (n=7)', which showed ramp depolarization and frequent action potentials (4.2+/-0.9 spikes/s) with rare excitatory postsynaptic potentials (EPSPs); 'irregularly firing neurons (n=21)', which exhibited many EPSPs that modulated the firing rate; and 'silent-type neurons (n=5)', which discharged action potentials only during current-induced depolarization. Lucifer-Yellow staining showed that the irregularly firing neurons were significantly larger and had more dendrites than the regularly firing neurons. All regularly firing neurons retained their discharges during low-Ca2+ -high-Mg2+ superfusion that blocks synaptic input, whereas the discharges in 11 of 16 irregularly firing neurons were abolished, suggesting that the regularly firing neurons discharged independently of synaptic input. Seven of 31 RVLM neurons were hyperpolarized by stimulation of vagal afferent nerves. In summary, three types of RVLM presympathetic neurons were characterized by the patch-clamp technique in the brainstem-spinal cord preparation, in which the connection was preserved from vagal afferent to the Th2 spinal segment through the RVLM. Since antidromic action potentials were demonstrated by stimulation in the Th2 spinal segment in 33 neurons of all three types, all types of RVLM neurons constitute a part of the sympathetic neuronal network.

Trypsin inhibitory activity of bovine fetuin de-O-glycosylated by endo-alpha-N-acetylgalactosaminidase

The effects of bovine fetuin O-glycans on its trypsin inhibitory activity were examined. De-sialylated (asialo-) and de-O-glycosylated fetuin were prepared from native fetuin using Arthrobacter neuraminidase and the mixture of it and Bacillus endo-alpha-N-acetylgalactosaminidase, respectively. De-sialylation and de-O-glycosylation from fetuin were confirmed with SDS-PAGE followed by western blotting using anti-human Thomsen-Friedenreich antigen (T antigen) antibody which recognizes O-linked galactosyl beta1,3 N-acetylgalactosamine (Gal beta1-->3GalNAc). Native fetuin completely inhibited the trypsin activity at about a 1:1 molar ratio. In contrast, the trypsin inhibitory activity of asialo- and de-O-glycosylated fetuin decreased about a half and one-third of that of native fetuin, respectively.

Development of a high-power deep-ultraviolet continuous-wave coherent light source for laser cooling of silicon atoms

We developed a deep-UV single-mode coherent light source through two-stage highly efficient frequency conversions by use of external cavities. In the first stage, second-harmonic power of 500 mW was obtained by frequency doubling of a 746-nm Ti:sapphire laser with a conversion efficiency of 40%. In the second stage, 50-mW power at ~252nm was obtained by doubly resonant sum-frequency mixing of 373-nm light from the first-stage conversion and 780-nm light from a diode laser. The output performance of this deep-UV light source is sufficient for laser cooling of neutral silicon atoms.

Amlodipine is comparable to angiotensin-converting enzyme inhibitor for long-term renoprotection in hypertensive patients with renal dysfunction: a one-year, prospective, randomized study

Unlike angiotensin converting enzyme inhibitors (ACEI), few long-term studies have shown calcium antagonists to retard the progression of renal dysfunction. Our aim was to prospectively compare the effects of amlodipine and ACEI (enalapril) on renal function in hypertensive patients with renal impairment due to chronic glomerulonephritis and essential hypertension. A total of 72 hypertensive patients with serum creatinine (Cr) > 1.5 mg/dL were randomly allocated to treatment with either drug. During a 1-year period, 33% of the patients treated with ACEI dropped out due to adverse events, whereas 9% of patients with amlodipine dropped out. Data of 28 patients were available for analysis of more than 1-year follow-up. Reductions in blood pressure were comparable between the amlodipine (from 165/101 to 138/81 mm Hg) and ACEI groups. Serum Cr increased from 2.1+/-0.8 (SD) to 2.6+/-1.0 mg/dL with amlodipine (n = 16), but the difference was equivalent to that with ACEI (n = 12). Creatinine clearance (Ccr) in the moderate dysfunction group (basal Cr, 1.5 to 2.0 mg/dL) changed from 36+/-10 to 33+/-11 mL/min (not significant) with amlodipine, and the change was similar to that noted with ACEI. Annual declines in Ccr with amlodipine (-3.7 mL/min/year) and ACEI (-2.6 mL/min/year) were comparable, and both tended to be smaller than the annual decline in glomerular filtration rate reported in the Modification of Diet in Renal Disease study (-6 mL/min/year). Serum potassium was increased significantly (P < .01), from 4.5+/-0.4 to 5.3+/-0.8 mEq/L, only in the ACEI group. This 1-year prospective study demonstrated the effect of amlodipine on renal function to be likely the same as that of ACEI. Furthermore, amlodipine was better tolerated than ACEI for hypertensive patients with renal dysfunction.