Riedel thyroiditis: Fine needle aspiration findings of a rare entity

Riedel thyroiditis is a rare fibrosing disorder characterized by extension of the fibroinflammatory process beyond the thyroid capsule. Due to the nature of this lesion, fine‐needle aspiration often yields scant material and may be interpreted as non‐diagnostic. In this report, we describe cytologic features that allow the cytopathologist to favor a diagnosis of Riedel thyroiditis, thereby guiding appropriate further work‐up and management. Diagn. Cytopathol. 2015;43:747–750. © 2015 Wiley Periodicals, Inc.     

Ultra-small palladium nano-particles synthesized using bulky S/Se and N donor ligands as a stabilizer: application as catalysts for Suzuki–Miyaura coupling

Two chalcogenated ligands L1 and L2 containing anthracene core and amine functionality have been synthesized. Both the ligands have been characterized using ¹H and ¹³C{¹H} NMR techniques. The structure of L1 has also been corroborated by single crystal X-ray diffraction. Application of L1 and L2 as stabilizers for palladium nano-particles (NPs) has been explored and six different types of NPs 1–6 have been prepared by varying the quantity of stabilizer. The nano-particles have been characterized by PXRD, EDX, and HRTEM techniques. The size of NPs has been found to be in the range of ∼1–2 nm, 2–3 nm, 4–6 nm, 1–2 nm, 1–2 nm and 3–5 nm for 1–6 respectively. The catalytic activities of 1–6 have been explored for Suzuki–Miyaura coupling of phenyl boronic acid with various aryl halides. These NPs showed good catalytic activity for various aryl chlorides/bromides at low catalyst loading (5 mg). Among 1–6, the highest activity has been observed for NPs 1, probably due to their relatively small size and high uniformity in the dispersion. The recyclability of the NPs upto 5 catalytic cycles is a distinct advantage.

Monodispersed ultrasmall Pd nanoparticles synthesized utilizing bulky organochalcogen secondary amines as stabilizers and application in Suzuki coupling of aryl chlorides at low catalyst loading.     

HIV with Juvenile Dermatomyositis

Dermatomyositis with HIV infection has been very rarely reported. The authors report an 8-y-old boy who presented with skin rashes and edema, muscle weakness and polymicrobial infection along with mild immunosupression. Diagnosis of dermatomyositis was established by raised enzymes, suggestive MRI and muscle biopsy findings. Child responded to systemic steroids and low dose weekly methotrexate.     

A Survey of Pulmonary Function Abnormalities Following Thoracotomy

Objective

To study the incidence and type of pulmonary function abnormalities after thoracotomy in children.

Methods

Children below 12 y of age who had undergone thoracotomy for any condition and have at least 2 y follow up were included in the study. Detailed assessment of the patients included history and general examination, clinical assessment of pulmonary function, bedside tests to assess pulmonary function and laboratory pulmonary function test using portable spirometer.

Results

Fifty two patients were included in the study. Twenty-seven were cases of esophageal atresia with trachea-esophageal fistula (EATEF), nine pulmonary metastasis from abdominal solid tumors, six mediastinal masses, three hydatid cyst, three eventration of diaphragm, two bronchiectasis, and one each of H-type TEF and congenital esophageal stenosis. The mean age at the time of evaluation was 6.3 y (range 2–18 y). While all the patients were clinically assessed, only 25 (48 %) were eligible for bedside tests and 23 (44 %) for spirometery. The incidences of abnormalities picked were: dyspnea during exercise 8/52 (15.4 %), dyspnea on exercise and on climbing stairs 1/52 (2 %), decreased breath holding time 2/25 (8 %), abnormal incentive spirometry 1/25 (4 %), mild restrictive pattern on pulmonary function test (PFT) 11/23 (47.8 %), moderate restrictive pattern on PFT 2/23 (8.7 %). None had an obstructive pattern on PFT.

Conclusions

Though the incidences of pulmonary function abnormalities were high, these were of mild grade. Close follow up of patients after thoracotomy would be needed for early pick up and appropriate management of these abnormalities to prevent long-term consequences.     

Fractional exhaled nitric oxide in children with acute exacerbation of asthma

Objective

To determine whether fractional exhaled nitric oxide (FENO) has a utility as a diagnostic or predictive maker in acute exacerbations of asthma in children.

Design

Analysis of data collected in a pediatric asthma cohort.

Setting

Pediatric Chest Clinic of a tertiary care hospital

Methods

A cohort of children with asthma was followed up every 3 months in addition to any acute exacerbation visits. Pulmonary function tests (PFT) and FENO were obtained at all visits. We compared the FENO values during acute exacerbations with those at baseline and those during the follow up.

Results

243 asthmatic children were enrolled from August 2009 to December 2011 [mean (SD) follow up — 434 (227) days]. FENO during acute exacerbations was not different from FENO during follow up; however, FENO was significantly higher than personal best FENO during follow up (P < 0.0001). FENO during acute exacerbation did not correlate with the severity of acute exacerbation (P=0.29). The receiver operating characteristics curve for FENO as a marker for acute exacerbation had an area under the curve of 0.59. Cut-off of 20 ppb had a poor sensitivity (44%) and specificity (68.7%) for acute exacerbation.

Conclusions

FENO levels during acute exacerbation increase from their personal best levels. However, no particular cut off could be identified that could help in either diagnosing acute exacerbation or predicting its severity.     

Pivotal role for the ubiquitin Y59-E51 loop in lysine 48 polyubiquitination

Lysine 48 (K48)-polyubiquitination is the predominant mechanism for mediating selective protein degradation, but the underlying molecular basis of selecting ubiquitin (Ub) K48 for linkage-specific chain synthesis remains elusive. Here, we present biochemical, structural, and cell-based evidence demonstrating a pivotal role for the Ub Y59-E51 loop in supporting K48-polyubiquitination. This loop is established by a hydrogen bond between Ub Y59’s hydroxyl group and the backbone amide of Ub E51, as substantiated by NMR spectroscopic analysis. Loop residues Y59 and R54 are specifically required for the receptor activity enabling K48 to attack the donor Ub-E2 thiol ester in reconstituted ubiquitination catalyzed by Skp1-Cullin1-F-box (SCF)^βTrCP E3 ligase and Cdc34 E2-conjugating enzyme. When introduced into mammalian cells, loop-disruptive mutant Ub^R54A/Y59A diminished the production of K48-polyubiquitin chains. Importantly, conditional replacement of human endogenous Ub by Ub^R54A/Y59A or Ub^K48R yielded profound apoptosis at a similar extent, underscoring the global impact of the Ub Y59-E51 loop in cellular K48-polyubiquitination. Finally, disulfide cross-linking revealed interactions between the donor Ub-bound Cdc34 acidic loop and the Ub K48 site, as well as residues within the Y59-E51 loop, suggesting a mechanism in which the Ub Y59-E51 loop helps recruit the E2 acidic loop that aligns the receptor Ub K48 to the donor Ub for catalysis.Central to selective protein turnover by the 26S proteasome is the formation of homotypic lysine 48 (K48)-linked ubiquitin (Ub) chains that tag substrate proteins for degradation (1). Among the most extensively studied systems that produce K48-linked Ub chains is the SCF (Skp1-Cullin1-F-box) E3-directed ubiquitination. SCF is a member of the multisubunit Cullin-RING E3 Ub ligase (CRL) family, the largest of all E3s (2). CRL contains a tandem of a large scaffold protein [Cullin (CUL)] and a RING domain-containing protein (ROC1/Rbx1) that typically associates with an adaptor protein (such as Skp1) in complex with a substrate recognition protein (such as F-box protein). As such, the organization of CRL subunits positions the substrate receptor (such as the F-box protein) within the proximity of ROC1, which recruits an E2-conjugating enzyme that catalyzes the transfer of Ub to a bound substrate. In the SCF reconstitution system, K48-linked polyubiquitin chains on a substrate such as IκBα and β-catenin are produced in a two-step reaction. The E2 UbcH5c deposits the first Ub moiety, forming a substrate–Ub linkage, which is followed by repeated discharge of subsequent Ubs by E2 Cdc34 to form K48-specific Ub chains (3). Human Cdc34 contains a highly conserved charged acidic loop (residues 102–113) that participates in the elongation of K48 chains (4, 5). The current work addresses whether there are determinants on the Ub itself that dictate K48 linkage specificity and, moreover, how Cdc34 might recognize Ub K48.