Preparation of Supramolecular Miktoarm Star Copolymers with a Zinc Phthalocyanine Core through ATRP and RAFT Polymerization

Topological polymers have attracted considerable attention owing to their unique chemical and physical properties. This study demonstrates the formation of novel supramolecular miktoarm star copolymers with a zinc phthalocyanine (ZnPc) core using metal-ligand coordination interactions. Various linear polymers with pyridyl end groups, poly(methyl methacrylate), poly(vinyl acetate) and poly(N-vinyl carbazole), are prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization. This facilitates coordination to the ZnPc core of 4-armed star-shaped polystyrene prepared via atom-transfer radical polymerization (ATRP). Furthermore, the formation of a 1:1 complex of a ZnPc molecule and pyridyl group of the chain-transfer agent for RAFT is confirmed by absorption spectral studies and ¹ H NMR spectroscopic analyses. The concept of supramolecular complexation can be extended to the preparation of AB₄ -type supramolecular miktoarm star-shaped copolymers with functional cores.

Synthesis of Multisubstituted Benzenes from Phenols via Multisubstituted Benzynes

A new method to synthesize multifunctionalized arenes from simple phenols through aryne intermediates is described. Multisubstituted aryne precursors were prepared from phenols by Ir-catalyzed C–H borylation, deborylthiolation, O-triflylation, S-oxidation, and further modification through ortho-deprotonation directed by the sulfoxide moiety. Various multisubstituted arenes were synthesized by transformations of highly functionalized aryne intermediates generated from the o-sulfinylaryl triflates.

Structural Insight into the Reaction Mechanism of Ketosynthase-Like Decarboxylase in a Loading Module of Modular Polyketide Synthases

Ketosynthase-like decarboxylase (KS_Q) domains are widely distributed in the loading modules of modular polyketide synthases (PKSs) and are proposed to catalyze the decarboxylation of a malonyl or methylmalonyl unit for the construction of the PKS starter unit. KS_Q domains have high sequence similarity to ketosynthase (KS) domains, which catalyze transacylation and decarboxylative condensation in polyketide and fatty acid biosynthesis, except that the catalytic Cys residue of KS domains is replaced by Gln in KS_Q domains. Here, we present biochemical analyses of GfsA KS_Q and CmiP4 KS_Q, which are involved in the biosynthesis of FD-891 and cremimycin, respectively. In vitro analysis showed that these KS_Q domains catalyze the decarboxylation of malonyl and methylmalonyl units. Furthermore, we determined the crystal structure of GfsA KS_Q in complex with a malonyl thioester substrate analogue, which enabled identification of key amino acid residues involved in the decarboxylation reaction. The importance of these residues was confirmed by mutational analysis. On the basis of these findings, we propose a mechanism of the decarboxylation reaction catalyzed by GfsA KS_Q. GfsA KS_Q initiates decarboxylation by fixing the substrate in a suitable conformation for decarboxylation. The formation of enolate upon decarboxylation is assisted by two conserved threonine residues. Comparison of the structure of GfsA KS_Q with those of KS domains suggests that the Gln residue in the active site of the KS_Q domain mimics the acylated Cys residue in the active site of KS domains.

Identification of children with first afebrile seizure for whom neuroimaging is unnecessary

PURPOSE

To find ways to identify children with first afebrile seizure for whom neuroimaging is unnecessary.

METHODS

We retrospectively reviewed the clinical records of children younger than 19 years of age with the first afebrile seizure who visited the emergency department of the National Center for Child Health and Development in Japan between May 2014 and December 2020. We investigated the relationship between age, sex, focal seizure, seizure duration, seizure cluster, neurological findings, and CT and/or MRI abnormalities by univariate analysis. Furthermore, to identify children with low probability of intracranial abnormality, we performed decision tree analysis by classification and regression tree methods.

RESULTS

Among the eligible 611 children, 14 children had a CT abnormality (4.2% of patients who underwent CT) and 26 had a CT or MRI abnormality (7.1% of patients who underwent CT or MRI). Six children had an urgent neuroimaging abnormality. In the univariate analysis, seizure cluster (P = 0.02) was significantly associated with CT abnormality, and focal seizure (P = 0.01) and seizure prolonged for more than 5 min (P = 0.04) were significantly associated with CT or MRI abnormality. The decision tree analysis identified seizure cluster, prolonged seizure, neurological disorder, and focal seizure as risk factors for CT abnormalities in that order.

CONCLUSION

Children without seizure cluster, seizure prolonged for more than 5 min, and neurological disorder may not require CT in the emergency room. The clinician could determine the necessity of neuroimaging by seizure cluster, prolonged seizure, focal seizure, and neurological disorder.

Molecular crystalline capsules that release their contents by light

Here, we present single crystalline capsules of a photoresponsive molecule produced by simple recrystallization from organic solutions without direct human processing. During the crystal growth process, a movie was taken of the capsule taking in the organic solution. The capsules responded rapidly (<1 s) to the UV light stimuli and released the captured solution or solute. In principle, they can take in any substance dissolved in organic solvents, and their size can be controlled. Moreover, the capsule can be broken by multi-photon excitation using a near-infrared laser within the biological window. Furthermore, because the molecular packing in the crystal is unidirectional, the response can be controlled by the polarization of the light. This study shows the new potential of photoresponsive molecules.

Clinical Prognostic Factors in Pediatric Patients With Orthostatic Intolerance

Midodrine is widely used for orthostatic intolerance (OI); however, little is known about the prognostic factors of OI after midodrine treatment. We retrospectively reviewed electronic medical charts to investigate clinical prognostic factors of OI on 159 OI patients aged 7 to 18 years who were treated with midodrine at a children's hospital. Logistic regression was conducted to clarify predictors for improving symptoms at the first month of the treatment. Patients with orthostatic uncomfortable feeling or fainting were significantly more likely to improve symptoms at the first month of the treatment (odds ratio [OR], 3.48; 95% confidence interval [95%CI], 1.36-8.89), but patients with underweight were significantly less likely to improve symptoms (OR, 0.19; 95%CI, 0.06-0.56). Our results suggest that predictive factors for OI by midodrine treatments are orthostatic symptoms and underweight in pediatric patients. These findings are useful to develop further studies for OI treatments.

Advanced pathologic study for definite diagnosis of mitochondrial cardiomyopathy

 

Mitochondrial cardiomyopathy (MCM) is usually recognized as one of the phenotypes of systemic mitochondrial disease. However if there are no cardiac symptoms, it is difficult to make a definite diagnosis because of various cardiovascular phenotypes and no diagnostic criteria in pathological examination. To add myocardial pathology to the diagnostic criteria for mitochondrial respiratory chain disorders, which is the gold standard in the diagnosis of mitochondrial diseases, we performed quantitative analysis of mitochondria using electron microscopy and immunohistopathologic analysis with respiratory chain enzyme antibodies. Ten patients with hypertrophic or restrictive cardiomyopathy who had undergone endomyocardial biopsy were studied. Respiratory chain enzymatic assay and genetic study were performed and four patients were diagnosed with MCM. Using electron microscopy with quantitative analysis, volume density of mitochondria within cardiac muscle cells was significantly increased in the MCM group compared to the non-MCM group (p=0.013). Immunohistopathologic results were compatible with the result of the respiratory chain enzymatic assay. These advanced pathological tests can distinguish MCM from other cardiomyopathies.

Results of immunopathologic study

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): The Practical Research Project for Rare/Intractable Diseases from the Japan Agency for Medical Research and Development, AMED.

Photoinduced swing of a diarylethene thin broad sword shaped crystal: a study on the detailed mechanism

We report a swinging motion of photochromic thin broad sword shaped crystals upon continuous irradiation with UV light. By contrast in thick crystals, photosalient phenomena were observed. The bending and swinging mechanisms are in fact due to molecular size changes as well as phase transitions. The first slight bending away from the light source is due to photocyclization-induced surface expansion, and the second dramatic bending toward UV incidence is due to single-crystal-to-single-crystal (SCSC) phase transition from the original phase I to phase IIUV. Upon visible light irradiation, the crystal returned to phase I. A similar SCSC phase transition with a similar volume decrease occurred by lowering the temperature (phase IIItemp). For both photoinduced and thermal SCSC phase transitions, the symmetry of the unit cell is lowered; in phase IIUV the twisting angle of disordered phenyl groups is different between two adjacent molecules, while in phase IIItemp, the population of the phenyl rotamer is different between adjacent molecules. In the case of phase IIUV, we found thickness dependent photosalient phenomena. The thin broad sword shaped crystals with a 3 μm thickness showed no photosalient phenomena, whereas photoinduced SCSC phase transition occurred. In contrast, large crystals of several tens of μm thickness showed photosalient phenomena on the irradiated surface where SCSC phase transition occurred. The results indicated that the accumulated strain, between isomerized and non-isomerized layers, gave rise to the photosalient phenomenon.

Skeletal muscle metastasis as a first site of recurrence of cervical cancer: A case report and review of the literature

RATIONALE

Cervical cancer primarily spreads through direct invasion or via local lymphatics, and hematogenous metastasis is infrequent. Previous reports have shown that lung, liver, and bone are the organs most frequently affected by hematogenous metastasis of cervical cancer, while skeletal muscle is very rarely involved.

PATIENT CONCERNS

A 75-year-old Japanese woman presented with a painful muscular mass in her right lower abdomen. Five years ago, she was treated for her International Federation of Gynecology and Obstetrics stage IB2 cervical adenocarcinoma with radical surgery plus adjuvant chemotherapy.

DIAGNOSES

The patient was diagnosed with isolated oblique muscle metastasis from cervical adenocarcinoma as a first site of recurrence.

INTERVENTIONS

The patient was treated with salvage surgery consisting of partial resection of the oblique muscle and ilium. The tumor was completely excised with an adequate surgical margin by a partial resection of the oblique muscle and ilium OUTCOMES:: The patient is currently free of disease at 10 months after the development of recurrent disease.

LESSONS

We describe a rare case of isolated oblique muscle metastasis as a first site of recurrence of the International Federation of Gynecology and Obstetrics stage IB2 cervical adenocarcinoma, which was successfully treated with surgery. Although skeletal muscle metastasis is rare, this condition should be considered during the follow-up period, especially when patients complain of muscular pain with insidious progression. The present case and our literature review highlighted the possibility that loco-regional treatment may be curative for selected recurrent cervical cancer developed in skeletal muscles.

A twisted macrocyclic hexanuclear palladium complex with internal bulky coordinating ligands

A macrocyclic hexanuclear palladium complex, which accumulates coordination sites on metals inside the cavity, was found to take a uniquely-twisted conformation when six molecules of a bulky pyridine derivative coordinated to the palladium.