Lymphoid tumor in the orbit: malignant or benign? MRI, histomorphological and molecular genetic analysis of eight cases

Differentiation between benign and malignant lymphoid infiltrates of the conjunctiva and the orbit is difficult even on the basis of histopathological appearance. We describe eight cases with low-grade malignant lymphoma, mucosa-associated lesion tissue (MALT) lymphoma. Laboratory analysis was done using microscopy, immunophenotyping and gene rearrangement using the Southern blot technique. DNA-rearrangement analysis allows a very precise determination of the benign and malignant lymphoid infiltrates of the ocular region. Our MRI findings show that these tumors can also generally be distinguished by their signal intensity on T2-weighted images. These findings might explain the favorable prognosis for MALT lymphoma of the conjunctiva and the orbit, and the absence of any recurrence in follow-ups ranging from 6 months to 9 years.     

Insulin autoimmune syndrome is the third leading cause of spontaneous hypoglycemic attacks in Japan

From 1979 to 1981, questionnaires were sent to 2094 hospitals throughout Japan to investigate the causes of severe hypoglycemic attacks other than the administration of oral hypoglycemic agents or insulin preparations. The survey revealed three main causes for the attacks, of which the first was insulinoma, the second extrapancreatic neoplasms, and the third was insulin autoimmune syndrome (IAS), in descending order. Seven years later, a second survey was carried out, which showed the order of the three disorders as the cause of the hypoglycemic attacks to be the same as in the first survey. In both studies it was suggested that the IAS was frequently induced by thiol compounds.     

SCE-963, a New Potent Cephalosporin with High Affinity for Penicillin-Binding Proteins 1 and 3 of Escherichia coli

A few biochemical activities of SCE-963, a new cephalosporin with potent antibacterial activities against gram-negative bacteria, were compared with those of several currently available cephalosporins against strains of Escherichia coli K-12. The minimum inhibitory concentrations of SCE-963, cefazolin, cephaloridine, cephalothin, and cephalexin were 0.2, 1.56, 3.13, 12.5, and 25 mug/ml, respectively. Affinities of these cephalosporins for the penicillin-binding protein (PBP) 1B of E. coli correlated well with their antibacterial activities; among tested cephalosporins, SCE-963 showed the highest affinity for PBP 1B. SCE-963 inhibited cross-linking of peptidoglycan in a cell-free system the most strongly suggesting that this inhibition results from its high affinity for PBP 1B. SCE-963 also showed the highest affinity for PBP 3; it caused filamentation of cells over a wide range of relatively lower concentrations. Thus its superior antibacterial activity is believed to be manifested through its high affinity for the PBPs.     

Effects of efonidipine hydrochloride on renal arteriolar diameters in spontaneously hypertensive rats.

Efonidipine, a calcium antagonist, has been reported to dilate not only afferent but also efferent arterioles, thereby reducing glomerular hydrostatic pressure. We investigated the effect of chronic treatment with efonidipine or lisinopril on the afferent and efferent arteriolar diameters by the vascular cast technique. Four-week-old spontaneously hypertensive rats (SHR) were divided into three groups: untreated, efonidipine (25 mg/kg/day)-treated, and lisinopril (3 mg/kg/day)-treated. At 22 weeks of age, the renal vasculatures were fixed at the maximally dilated condition. The morphometrical measurements showed that the treatments with efonidipine and lisinopril caused structural alteration of the vasculature, resulting in significantly greater efferent arteriolar diameters than in untreated SHR. In addition, lisinopril-treated rats had wider afferent lumina. The renoprotective effect of efonidipine and lisinopril might be partly due to the structurally larger efferent arteriolar lumen.     

Cerebrospinal fluid drainage through the diploic and spinal epidural veins

The aim of this study was to quantitatively evaluate the function of the cranial diploic and spinal epidural veins as cerebrospinal fluid (CSF) drainage pathways by measuring lipocalin‐type prostaglandin D synthase (PGDS) and cystatin C (CysC) dissolved in the blood of these veins. This was a prospective study involving 51 consecutive patients, 31 males and 20 females, who underwent 41 cranial and 10 spinal surgeries. Intraoperatively, peripheral venous blood and diploic venous blood, or peripheral venous blood and spinal epidural venous blood samples were simultaneously collected and immediately centrifuged. For all samples, dissolved albumin (for reference), PGDS and CysC were measured using an enzyme‐linked immunosorbent assay. The diploic vein/peripheral vein ratios in five cranial locations and epidural vein/peripheral vein ratios were calculated and statistically evaluated for the three biomarkers. For PGDS, the diploic vein/peripheral vein ratio was significantly increased in the frontal (P = 0.011), temporal (P = 0.028), parietal (P = 0.046) and skull base (P = 0.039), while it did not reach statistical significance for CysC. For patients older than 45 years, the diploic vein/peripheral vein ratio for PGDS was significantly decreased in the frontal region (P = 0.028), and the epidural vein/peripheral vein ratio for CysC was significantly decreased (P = 0.014). These results show that the diploic veins constitute CSF drainage pathways with heterogeneous functional intensity at different cranial locations. Compared with the diploic veins, spinal epidural veins seem to drain less CSF. The cranial diploic and spinal epidural veins may jointly function as an alternative, age‐related trans‐dural CSF drainage system.     

RNAi suppression of rice endogenous storage proteins enhances the production of rice-based Botulinum neutrotoxin type A vaccine

Mucosal vaccines based on rice (MucoRice) offer a highly practical and cost-effective strategy for vaccinating large populations against mucosal infections. However, the limitation of low expression and yield of vaccine antigens with high molecular weight remains to be overcome. Here, we introduced RNAi technology to advance the MucoRice system by co-introducing antisense sequences specific for genes encoding endogenous rice storage proteins to minimize storage protein production and allow more space for the accumulation of vaccine antigen in rice seed. When we used RNAi suppression of a combination of major rice endogenous storage proteins, 13 kDa prolamin and glutelin A in a T-DNA vector, we could highly express a vaccine comprising the 45 kDa C-terminal half of the heavy chain of botulinum type A neurotoxin (BoHc), at an average of 100 μg per seed (MucoRice-BoHc). The MucoRice-Hc was water soluble, and was expressed in the cytoplasm but not in protein body I or II of rice seeds. Thus, our adaptation of the RNAi system improved the yield of a vaccine antigen with a high molecular weight. When the mucosal immunogenicity of the purified MucoRice-BoHc was examined, the vaccine induced protective immunity against a challenge with botulinum type A neurotoxin in mice. These findings demonstrate the efficiency and utility of the advanced MucoRice system as an innovative vaccine production system for generating highly immunogenic mucosal vaccines of high-molecular-weight antigens.     

Crystal structures of an archaeal oligosaccharyltransferase provide insights into the catalytic cycle of N-linked protein glycosylation

Oligosaccharyltransferase transfers an oligosaccharide chain to the asparagine residues in proteins. The archaeal and eubacterial oligosaccharyltransferases are single subunit membrane enzymes, referred to as “AglB” (archaeal glycosylation B) and “PglB” (protein glycosylation B), respectively. Only one crystal structure of a full-length PglB has been solved. Here we report the crystal structures of the full-length AglB from a hyperthermophilic archaeon, Archaeoglobus fulgidus. The AglB and PglB proteins share the common overall topology of the 13 transmembrane helices, and a characteristic long plastic loop in the transmembrane region. This is the structural basis for the formation of the catalytic center, consisting of conserved acidic residues coordinating a divalent metal ion. In one crystal form, a sulfate ion was bound next to the metal ion. This structure appears to represent a dolichol-phosphate binding state, and suggests the release mechanism for the glycosylated product. The structure in the other crystal form corresponds to the resting state conformation with the well-ordered plastic loop in the transmembrane region. The overall structural similarity between the distantly related AglB and PglB proteins strongly indicates the conserved catalytic mechanism in the eukaryotic counterpart, the STT3 (stauroporine and temperature sensitivity 3) protein. The detailed structural comparison provided the dynamic view of the N-glycosylation reaction, involving the conversion between the structured and unstructured states of the plastic loop in the transmembrane region and the formation and collapse of the Ser/Thr-binding pocket in the C-terminal globular domain.Protein glycosylation on asparagine residues (N-glycosylation) is an important posttranslational modification that occurs in all domains of life (1). In eukaryotic cells, various glycoforms of oligosaccharides on proteins are used as a universal signal of the folding status of a protein, for quality control and degradation in the cells (2). Reflecting the essential roles of N-glycosylation in eukaryotes, the canonical Glc₃Man₉GlcNAc₂Asn glycan structure is well conserved in higher eukaryotes, such as animal, plant, and fungal species (2). Derivatives of the same structure with reduced complexity exist in lower eukaryotes, such as protozoan species (3, 4). In contrast, the glycan structures in archaea and eubacteria show a far greater variety of monosaccharides and their linkages (1, 5–7). This is probably because the N-glycosylation is not essential for survival in archaea and eubacteria, and the structures have been optimized for their special purposes. For example, N-glycosylation is important for the pathogenicity of the eubacterium Campylobacter jejuni, by increasing its adherence to and invasion of host cells (8).The entire process of protein N-glycosylation is divided into three steps: oligosaccharide donor synthesis, oligosaccharyl transfer reaction, and oligosaccharide processing. The first step is the production of the oligosaccharide donor, the lipid-linked oligosaccharide (LLO) (9). An oligosaccharide chain is assembled on a lipid-phospho carrier. In principle, the carrier is dolichol diphosphate in eukaryotes and archaea, and undecaprenol diphosphate in eubacteria, with the exceptions of halophilic and methanogenic archaea, which use dolichol monophosphate (10, 11).The second step is the transfer of the oligosaccharide chain, preassembled on the lipid-phospho carrier, onto proteins. A membrane-bound enzyme, oligosaccharyltransferase (OST), catalyzes the formation of a covalent bond between the sugar residue of the reducing end of the oligosaccharide chain and the side-chain amide groups of the asparagine residues in proteins (1, 7, 12). The catalytic subunit of the OST enzyme is a polypeptide chain referred to as “STT3” (staurosporine and temperature sensitivity 3) in eukaryotes, “AglB” (archaeal glycosylation B) in archaea, and “PglB” (protein glycosylation B) in eubacteria, although they originated from a common ancestor. The eukaryotic OST is a multisubunit protein complex containing STT3, but the lower eukaryotic protozoan OST, and the archaeal and eubacterial OSTs, are single subunit enzymes consisting only of the STT3/AglB/PglB protein (12–15). In principle, the acceptor asparagine resides in the N-glycosylation sequon (Asn-X-Ser/Thr; X ≠ Pro), but the glycosylation also occurs in atypical sequences, such as Asn-X-Cys, Asn-Gly-X, and Asn-X-Val (X ≠ Pro), albeit at very low frequencies (16, 17). Eubacteria use an extended and thus more restrictive version of the sequon (Asp/Glu-X-Asn-Y-Ser/Thr; X, Y ≠ Pro) (18, 19).In 2011, the crystal structure of the full-length Campylobacter lari PglB was reported at 3.4-Å resolution (20). The structure in a complex with an acceptor peptide provided many new insights into the catalytic mechanism of the oligosaccharyl transfer reaction. First, the C. lari PglB structure revealed several catalytically important residues on the extracellular loops in the N-terminal transmembrane (TM) region. The carboxylate groups of the two acidic residues contact the Asn side chain in the sequon, and simultaneously coordinate a divalent metal ion. The bipartite interactions with the two acidic residues twist the planar carboxamide group of the Asn side chain, thus freeing the lone-pair for nucleophilic attack. The Asn-X-Thr portion of the acceptor peptide adopts an extended conformation in the bound state, which ruled out the possibility of the direct involvement of the hydroxyl group of the +2 Ser/Thr residues in the reaction. Instead, the C-terminal globular domain contains a binding site for the Ser/Thr residues at the +2 position in the sequon. Thus, the +2 Ser/Thr residue, and especially its hydroxyl group, is used to guide the side-chain carboxamide group of the Asn residue into the catalytic site.We previously determined the crystal structures of the C-terminal globular domains of the three paralogous AglB proteins from Archaeoglobus fulgidus (21–23), as well as two other AglB proteins and one PglB protein (14, 22, 24). The structural comparison revealed a common structural unit that contains the Ser/ Thr pocket, and other structural units specific to each protein. These isolated C-terminal domains are catalytically inactive, but their structural comparison led to the discovery of a new conserved motif (14) and revealed the essential intrinsic flexibility in the C-terminal domain (22). In the present study, we determined the crystal structure of the full-length A. fulgidus AglB-Long (L) in two crystal forms, at 2.5-Å and 3.4-Å resolutions. The overall structure of A. fulgidus AglB-L shared high structural similarity with that of C. lari PglB. The comparison of the distantly related AglB and PglB proteins highlighted the well-conserved functional structures, and provided the dynamic view of the N-glycosylation reaction.     

Diagnostic value of measurement of serum type I procollagen carboxy terminal peptides in patients with scirrhous carcinoma of the stomach.

We have evaluated the radioimmunoassay for type I procollagen carboxy terminal peptide (type I C-peptide), which is liberated from type I procollagen during its conversion to collagen, in the serodiagnosis of scirrhous carcinoma of the stomach. The mean (SD) serum concentration of type I C-peptide in 39 normal subjects was 41.7 (19.7) ng/ml. The mean serum values and the positive ratio of type I C-peptide in 11 patients with stages II and III scirrhous carcinoma of the stomach were 91.2 (41.9) ng/ml and 54.5%, respectively. In 10 patients with other types of gastric carcinoma, the mean type I C-peptide values were not significantly different from the normal value. Serum type I C-peptide values reflected the clinical course of scirrhous gastric carcinoma in five patients who underwent either operation or chemotherapy. The measurement of serum type I C-peptide concentrations could provide a useful way of diagnosing and monitoring scirrhous carcinoma of the stomach.     

Clinical characteristics of pigmented macules on palms and/or soles appearing after middle age in Japan

We have examined the clinical characteristics of pigmented macules on palms and/or soles. A total of 238 inpatients and 111 healthy persons over 40 years old in Japan were included in our analysis. We found: (a) that such pigmented macules may occur not only on healthy persons but also on patients who suffer from various internal disorders, (b) that, in both males and females, the incidence of pigmented macules is relatively high in malignancy patients in comparison with non-malignancy and control individuals, (c) that the incidence is higher in males than in females, (d) that, in both males and females, there was a tendency toward distribution on both palms and soles in malignancy patients in comparison with the non-malignancy and control individuals (p<0.01), and (e) that, among cases with pigmented macules, the number of pigmented macules is empirically greater in inpatients (the malignancy and non-malignancy groups) than in the controls.