Profiles of central nervous system surgical site infections in endoscopic transnasal surgery exposing the intradural space.

OBJECTIVE: Despite its efficacy and minimal invasiveness, the clean-contaminated nature of endoscopic transnasal surgery (ETS) may be susceptible to central nervous system surgical site infections (CNS-SSIs), especially when involving intradural exposure. However, the profiles of ETS-associated CNS-SSIs are not fully elucidated. METHODS: The institutional ETS cases performed between May 2017 and March 2023 were retrospectively analysed. The incidences of CNS-SSIs were calculated, and their risk factors examined. RESULTS: The incidence of CNS-SSIs was 2.3% (7/305) in the entire cohort and 5.0% (7/140) in ETSs with intradural exposure. All the CNS-SSIs were meningitis and developed following ETS with intradural exposure. The incidences were 0%, 5.6% and 5.8% in ETSs with Esposito grade 1, 2 and 3 intraoperative cerebrospinal fluid leakage, respectively. Among the pre- and intra-operative factors, body mass index (unit odds ratio (OR), 0.62; 95% confidence interval (CI), 0.44-0.89; P<0.01), serum albumin (unit OR, 0.03; 95% CI, 0.0007-0.92; P=0.02), and American Society of Anesthesiologists physical status score (unit OR, 20.7; 95% CI, 1.65-259; P<0.01) were significantly associated with CNS-SSIs. Moreover, postoperative cerebrospinal fluid leakage was also significantly associated with CNS-SSIs (OR, 18.4; 95% CI, 3.55-95.0; P<0.01). CONCLUSIONS: The incidence of ETS-associated CNS-SSIs is acceptably low. Intradural exposure was a prerequisite for CNS-SSIs. Malnutrition and poor comorbidity status should be recognized as important risks for CNS-SSIs in ETS.

Direct observation of charge transfer in double-perovskite-like RbMn[Fe(CN)6].

The charge density distribution has been determined for a transition metal cyanide, RbMn[Fe(CN)(6)], by means of the maximum entropy-Rietveld method combined with the highly angularly resolved synchrotron radiation x-ray powder diffraction at SPring-8 BL02B2. We directly observed a charge transfer from the Mn site to the Fe site in the low-temperature phase. On the basis of a local density approximation calculation, we discuss the origin for the anisotropic bonding electron distribution around the Mn3+ ion in the low-temperature phase.

Stichopus japonicus arginine kinase: gene structure and unique substrate recognition system.

Arginine kinase from the sea cucumber Stichopus japonicus underwent a unique molecular evolution. Unlike the monomeric 40 kDa arginine kinases from molluscs and arthropods, Stichopus arginine kinase is dimeric, the same as cytoplasmic isoenzymes of the vertebrate creatine kinases. Its entire amino acid sequence is more similar to creatine kinases than to other arginine kinases, but the guanidino specificity region (GS region) is of the arginine kinase type. To elucidate its unusual evolution, the structure of the Stichopus arginine kinase gene was determined. It consisted of seven exons and six introns, and a part of the exon 2 of the Stichopus gene corresponds to the GS region. Compared with the structure of the human muscle creatine kinase gene (seven exons, six introns), the splice junctions of five introns were conserved exactly between the two genes, suggesting that these introns had been conserved for at least 500 million years. The entire sequence of Stichopus arginine kinase is distinctly included in the creatine kinase cluster in all tree construction methods examined. On the other hand, if the tree is constructed only from sequences corresponding to Stichopus exon 2, it is placed in the arginine kinase cluster. Thus we conclude that Stichopus arginine kinase evolved not from the arginine kinase gene but from the creatine kinase gene, and suggest that its GS region, determining substrate specificity, has been replaced by an arginine kinase type via exon shuffling. In typical arginine kinases four residues, Ser(63), Gly(64), Val(65) and Tyr(68) (numbering from the Limulus polyphemus sequence), in the GS region are highly conserved and are associated with substrate binding. Among them, Tyr(68) appears to play a crucial role by forming a hydrogen bond with the substrate, and is conserved exactly in all arginine kinases. However, in Stichopus arginine kinase, none of these four conserved residues were present. Nevertheless, the enzyme displays an affinity for the substrate arginine (K(m)=0.8 mM) comparable with other arginine kinases. This implies that a completely different substrate-binding system has been developed in Stichopus arginine kinase. We propose that the His(64) in Stichopus arginine kinase acts as a substitute for the Tyr(68) in other arginine kinases, and that the imidazole ring of His(64) is hydrogen bonded with the substrate arginine, thus stabilizing it.

Arginine kinase from Nautilus pompilius, a living fossil. Site-directed mutagenesis studies on the role of amino acid residues in the Guanidino specificity region.

Arginine kinases were isolated from the cephalopods Nautilus pompilius, Octopus vulgaris, and Sepioteuthis lessoniana, and the cDNA-derived amino acid sequences have been determined. Although the origin and evolution of cephalopods have long been obscure, this work provides the first molecular evidence for the phylogenetic position of Cephalopoda in molluscan evolution. A crystal structure for Limulus arginine kinase showed that four amino acid residues (Ser(63), Gly(64), Val(65), and Tyr(68)) are hydrogen-bonded with the substrate arginine. We introduced three independent mutations, Ser(63) --> Gly, Ser(63) --> Thr, and Tyr(68) --> Ser, in Nautilus arginine kinase. One of the mutants had a considerably reduced substrate affinity, accompanied by a decreased V(max). In other mutants, the activity was lost almost completely. It is known that substantial conformational changes take place upon substrate binding in arginine kinase. We hypothesize that the hydrogen bond between Asp(62) and Arg(193) stabilizes the closed, substrate-bound state. Site-directed mutagenesis studies strongly support this hypothesis. The mutant (Asp(62) --> Gly or Arg(193) --> Gly), which destabilizes the maintenance of the closed state and/or perhaps disrupts the unique topology of the catalytic pocket, showed only a very weak activity (0.6-1.5% to the wild-type).

Evolution of phosphagen kinase VII. Isolation of glycocyamine kinase from the polychaete Neanthes diversicolor and the cDNA-derived amino acid sequences of alpha and beta chains.

Glycocyamine kinase (GK) was isolated from the marine polychaete Neanthes diversicolor by gel filtration, DEAE-cellulose chromatography, butyl-Toyopearl hydrophobic chromatography, and chromatofocusing. The GK was eluted as a single peak on the latter three chromatographies, and the molecular mass for the native GK was estimated to be about 80 kDa. The SDS-PAGE showed that the isolated GK consists of two distinct subunits in equal proportion, alpha and beta chains, with molecular masses of 42.2 and 43.8 kDa, respectively. The present results suggest that the Neanthes GK has a heterodimeric structure. The cDNAs for alpha and beta chains of Neanthes GK were amplified by PCR and their cDNA-derived amino acid sequences were determined. The alpha and beta chains are composed of 374 and 390 amino acids, and the molecular masses were calculated to be 42,392 and 43,966 Da, respectively, in good agreement with the apparent masses on SDS PAGE. The beta chain has a characteristic N-terminal extension of 15 amino acids, and all of the sequence differences between alpha and beta chains were restricted in the N-terminal region of 50 residues. The overall sequence identity was 92%. The occurrence of heterodimeric nature in Neanthes GK is of great interest from the evolutionary point of view, because the heterodimeric structure is only known for creatine kinase MB-isozyme specific for mammalian heart muscle among phosphagen kinases.

Fine structure of SMG alginate fragment in the light of its degradation by alginate lyases of Pseudomonas sp.

An alginate fragment named SMG, consisting of mannuronic (M) and guluronic acid residues (G)(DP=25), was prepared from the partial acid hydrolysate of a commercial alginate. Two subfractions, SMG-ppt (DP=52) and SMG-sup (DP=18) were obtained from SMG by fractionation with MgC12 and CaC12. The M/G ratios of these alginate fragment were 1.4-1.9. Their lysis products by a pseudomonad alginate lyase [EC 4.2.2.3] preparation were fractionated by gel filtration, giving similar patterns. The major products in their digests were unsaturated monouronides (53-50%) and triuronides (30-35%). The former was identified as a delta4,5-hexuronic acid (deltaU) and the latter was identified as a mixture of delta4,5-hexuronosyl-(1 leads to 4)-beta-D-mannuronosyl-(1 leads to 4)-L-guluronic acid (deltaUMG) and delta4,5-hexuronosyl-(1 leads to 4)-alpha-L-guluronosyl-(1 leads to 4))L-guluronic acid (deltaUGG). The two unsaturated triuronides were present in roughly equal amounts. The presence of 4-O-alpha-L-guluronosyl-L-guluronic acid (GG) and 4-O-beta-D-mannuronosyl-L-guluronic acid (MG) or 4-O-beta-L-guluronosyl-D-mannuronic acid (GM) was also demonstrated inthe digest. Moreover, indirect evidence suggested nonreducing terminal deltaU residue and free deltaU in the digest to be derived more from M than G of the original SMG. Thus, it was concluded that more than one-third of uronic acid residues of SMG molecules may be composed of almost equal amounts of MG and GG sequences, most of which may be connected by M to form MMG and MGG sequences, respectively.