Direct Observation of a Cyclic Vinyl Polymer Prepared by Anionic Polymerization using N‐Heterocyclic Carbene and Subsequent Ring‐Closure without Highly Diluted Conditions

A 1:1 adduct of methyl sorbate (MS) and 1,3‐di‐tert‐butylimidazol‐2‐ylidene (NHCtBu) initiates anionic polymerization of a nonconjugated polar alkene, allyl methacrylate (AMA) in toluene at ?20 °C. After the monomer is consumed quantitatively using a bulky aluminum Lewis acid, methylaluminum bis(2,6‐di‐tert‐butyl‐4‐methylphenoxide) (MAD), as an additive, successive ring‐closure occurs without highly dilute conditions to give a cyclic poly(AMA) containing α‐terminal MS unit, and an M_n of 8.8 × 10³?58.5 × 10³ with a narrow molecular dispersity index (M_w/M_n = 1.1₄–1.3₇). The lack of a need for dilution is due to the fact that an α‐terminal NHCtBu group is acting as the counter cation for the propagating center in the polymerization. From ¹H NMR and matrix assisted laser desorption/ionization (MALDI‐TOF) mass spectra, combined with transmittance electron microscope (TEM) observation of a synthesized poly(AMA) with longer alkyl side chains prepared via a thiol‐ene click reaction, it is concluded that once the monomer is consumed, nucleophilic attack at the neighboring methine of the α‐terminal NHCtBu residue by the propagating anionic center causes ring‐closing to cyclic poly(AMA).     

Gastric volvulus and giant Bochdalek hernia in an adult patient that were safely repaired by endoscopic reduction and elective laparoscopic surgery

A Bochdalek hernia (BH) is a congenital abnormality with incomplete closure of the diaphragm. It is usually manifested in infants but rarely in adults. Here, we report an adult patient with gastric volvulus and giant BH that were safely repaired by endoscopic reduction and elective laparoscopic surgery, respectively. A 79-year-old woman presented with left upper abdominal pain but no history of trauma. CT revealed a giant BH with gastric volvulus. After emergency endoscopic reduction of the volvulus, elective laparoscopic repair of the BH was performed. The 8 × 8-cm defect was repaired with interrupted nonabsorbable sutures and a mesh. The patient's postoperative course was uneventful, and no complications or recurrence were observed in the 6 months that followed.     

Three cases of COVID-19 patients presenting with erythema

Individuals infected with the novel coronavirus (Severe Acute Respiratory Syndrome Coronavirus 2 [SARS-CoV-2]) who develop coronavirus disease 2019 (COVID-19) experience many symptoms; however, cutaneous manifestations are relatively rare. The authors encountered three patients with COVID-19 who presented with erythema and suspected viral rash. In all cases, erythema appeared after the onset of the initial symptoms of COVID-19. Erythema was considered to be caused by COVID-19 and not a drug-induced eruption because, in all cases, erythema was relieved merely by external medicine and oral antihistamines, without discontinuing the original medication. The authors’ hospital accepted 69 COVID-19 patients between 22 February 2020 and 31 May 2020 and, of these, three (4.3%) exhibited eruptions, and all cases presented erythema. Except for seven patients who exhibited positive nasopharyngeal swab tests for SARS-CoV-2 RNA but no symptoms, three (4.8%) of the remaining 62 patients exhibited erythema. Although various types of eruptions have been reported in patients with COVID-19, erythema was the only type in our patients. Erythema in the three patients exhibited many similarities to that previously reported in COVID-19 patients, particularly in the manner it appeared and disappeared. For these reasons, these three cases were considered typical examples of erythema in patients with COVID-19. Considering previous studies and the three cases reported here, there is a high probability that SARS-CoV-2 can cause erythema.     

Generation and characterization of a novel shoulder contracture mouse model

Frozen shoulder is a relatively common disorder that leads to severe pain and stiffness in the shoulder joint. Although this disorder is self‐limiting in nature, the symptoms often persist for years, resulting in severe disability. Recent studies using human specimens and animal models have shown distinct changes in the gene expression patterns in frozen shoulder tissue, indicating that novel therapeutic intervention could be achieved by controlling the genes that are potentially involved in the development of frozen shoulder. To achieve this goal, it is imperative to develop a reliable animal joint contracture model in which gene expression can be manipulated by gene targeting and transgenic technologies. Here, we describe a novel shoulder contracture mouse model. We found that this model mimics the clinical presentation of human frozen shoulder and recapitulates the changes in the gene expression pattern and the histology of frozen shoulder and joint contracture in humans and other larger animal models. The model is highly reproducible, without any major complications. Therefore, the present model may serve as a useful tool for investigating frozen shoulder etiology and for identifying its potential target genes. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1732–1738, 2015.