Tandem quadrupole Fourier-transform mass spectrometry of oligopeptides and small proteins.

Modifications to the newly developed tandem quadrupole Fourier-transform mass spectrometer have made it possible to record mass spectra on oligopeptides and small proteins in the mass range between 2 and 13 kDa.     

Exploring the utility of whole‐exome sequencing as a diagnostic tool in a child with atypical episodic muscle weakness

The advent of whole‐exome next‐generation sequencing (WES) has been pivotal for the molecular characterization of Mendelian disease; however, the clinical applicability of WES has remained relatively unexplored. We describe our exploration of WES as a diagnostic tool in a 3½‐year old female patient with a 2‐year history of episodic muscle weakness and paroxysmal dystonia who presented following a previous extensive but unrevealing diagnostic work‐up. WES was performed on the proband and her two parents. Parental exome data was used to filter potential de novo genomic events in the proband and suspected variants were confirmed using di‐deoxy sequencing. WES revealed a de novo non‐synonymous mutation in exon 21 of the calcium channel gene CACNA1S that has been previously reported in a single patient as a rare cause of atypical hypokalemic periodic paralysis. This was unexpected, as the proband's original differential diagnosis had included hypokalemic periodic paralysis, but clinical and laboratory features were equivocal, and standard clinical molecular testing for hypokalemic periodic paralysis and related disorders was negative. This report highlights the potential diagnostic utility of WES in clinical practice, with implications for the approach to similar diagnostic dilemmas in the future.     

Processing of vestibular inputs by the medullary lateral tegmental field of conscious cats: implications for generation of motion sickness

The dorsolateral reticular formation of the caudal medulla, the lateral tegmental field (LTF), participates in generating vomiting. LTF neurons exhibited complex responses to vestibular stimulation in decerebrate cats, indicating that they received converging inputs from a variety of labyrinthine receptors. Such a convergence pattern of vestibular inputs is appropriate for a brain region that participates in generating motion sickness. Since responses of brainstem neurons to vestibular stimulation can differ between decerebrate and conscious animals, the current study examined the effects of whole-body rotations in vertical planes on the activity of LTF neurons in conscious felines. Wobble stimuli, fixed-amplitude tilts, the direction of which moves around the animal at a constant speed, were used to determine the response vector orientation, and also to ascertain whether neurons had spatial–temporal convergence (STC) behavior (which is due to the convergence of vestibular inputs with different spatial and temporal properties). The proportion of LTF neurons with STC behavior in conscious animals (25 %) was similar to that in decerebrate cats. Far fewer neurons in other regions of the feline brainstem had STC behavior, confirming findings that many LTF neurons receive converging inputs from a variety of labyrinthine receptors. However, responses to vertical plane vestibular stimulation were considerably different in decerebrate and conscious felines for LTF neurons lacking STC behavior. In decerebrate cats, most LTF neurons had graviceptive responses to rotations, similar to those of otolith organ afferents. However, in conscious animals, the response properties were similar to those of semicircular canal afferents. These differences show that higher centers of the brain that are removed during decerebration regulate the labyrinthine inputs relayed to the LTF, either by gating connections in the brainstem or by conveying vestibular inputs directly to the region.     

Adaptation and evaluation of a child-friendly patient reported outcome measure for use in Australia

BackgroundUse of Patient Reported Outcomes (PROs) to assess symptoms in children are not routinely used in clinical practice, yet children with complex conditions experience a significant number of symptoms.AimTo adapt and evaluate the Symptom Screening in Pediatrics Tool (SSPedi), a PRO measure developed in Canada for use with Australian children.MethodsSSPedi wording was adapted and item relevance assessed by an expert clinical group (N = 7) resulting in the Australian version (SSPedi-Aus). Cognitive interviewing with children with cancer (N = 10, 8–18 years) established understanding and difficulty with completing. A second group of child-parent dyads (N = 30) were recruited to evaluate psychometric properties (content validity, test-retest reliability, and parent-proxy) measured with Intraclass Correlation Coefficients (ICC) with 95% Confidence Intervals (CI). Acceptability and usefulness of SSPedi-Aus were also assessed.FindingsConstruct validity was confirmed across all items by 30 children. Child test-retest achieved excellent concordance (ICC 0.98, 95% CI 0.91 to 0.99). Symptoms causing the most distress as reported by children were different to those identified by parents. Although children and parents returned a similar mean total score (13.43 vs. 13.80), there was weak overall interrater reliability (ICC 0.37, 95% CI ?0.26 to 0.70, p = 0.12).ConclusionChildren are distressed by symptoms that may not be identified by parents or reported to clinicians, yet these symptoms are amendable to intervention. The SSPedi-Aus is useful to assess the level of distress caused by symptoms in children.     

Factors influencing decision‐making processes for unwell residents in residential aged care: Hospital transfer or Residential InReach referral?

Objective

To investigate decision‐making around hospital transfer and/or referral of residents to a Residential InReach (RiR) service in north‐eastern metropolitan Melbourne, Australia, from the perspectives of residential aged care facility (RACF) staff, general practitioners (GPs) and RiR registered nurses (RNs).

Methods

Thirty‐one staff from eight RACFs, five GPs and four RiR RNs participated in individual or group interviews.

Results

Residential aged care facility staff and GPs valued and relied upon RiR to manage unwell residents. Thematic analysis identified RiR utilisation was driven by the following: (i) complexity of decision‐making processes in RACFs; (ii) variability in facility‐based medical and nursing care; and (iii) impact of RiR service outcomes on patients and referrers.

Conclusion

Availability of timely and appropriate medical and nursing care in RACFs was reported to influence transfers to the hospital and/or referrals to RiR. RiR was used to complement or substitute usual care available to residents. Further research and improvements in RACF and RiR resources are required.

     

RCS1, a substrate of APC/C, controls the metaphase to anaphase transition

The anaphase-promoting complex/cyclosome (APC/C) controls the onset of anaphase by targeting securin for destruction. We report here the identification and characterization of a substrate of APC/C, RCS1, as a mitotic regulator that controls the metaphase-to-anaphase transition. We showed that the levels of RCS1 fluctuate in the cell cycle, peaking in mitosis and dropping drastically as cells exit into G₁. Indeed, RCS1 is efficiently ubiquitinated by APC/C in vitro and degraded during mitotic exit in a Cdh1-dependent manner in vivo. APC/C recognizes a unique D-box at the N terminus of RCS1, as mutations of this D-box abolished ubiquitination in vitro and stabilized the mutant protein in vivo. RCS1 controls the timing of the anaphase onset, because the loss of RCS1 resulted in a faster progression from the metaphase to anaphase and accelerated degradation of securin and cyclin B. Biochemically, mitotic RCS1 associates with the NuRD chromatin-remodeling complex, and this RCS1 complex is likely involved in regulating gene expression or chromatin structure, which in turn may control anaphase onset. Our study uncovers a complex regulatory network for the metaphase-to-anaphase transition.