Risk-reducing laparoscopic cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for low-grade appendiceal mucinous neoplasm: early outcomes and technique

Background

Low-grade appendiceal mucinous neoplasm (LAMN) is a precursor lesion of pseudomyxoma peritonei, which, if treated suboptimally, may later disseminate throughout the abdominal cavity. We previously demonstrated the role of cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) to reduce the dissemination risk. Here we describe the feasibility and safety of minimal access cytoreductive surgery (MACRS) and HIPEC as an alternative to the open approach.

Methods

We evaluated patients with LAMNs at risk of dissemination (known as LAMN II) who were referred to a national treatment centre between 2010 and 2012 and comparison is made between this group and patients undergoing open CRS and HIPEC for the same pathology over the same time period.

Results

Of the 39 patients with LAMN II, 10 patients were treated by MACRS and HIPEC and 7 were treated by an open approach. Among the MACRS procedures, there were no conversions to open surgery; median procedure length, median length of stay, and complication rates were similar between groups and there were no 30-day deaths. After 3- and 11-months median follow-up respectively, no patients have evidence of disease progression.

Conclusions

The present series demonstrates that MACRS and HIPEC is a feasible and safe alternative to the open procedure with the advantage of smaller abdominal wounds and comparable morbidity and inpatient stay. Longer follow-up is needed to assess the impact on disease progression.     

Acute surgical wound‐dressing procedure: Description of the steps involved in the development and validation of an observational metric

The aim of this study was to develop an observational metric that could be used to assess the performance of a practitioner in completing an acute surgical wound‐dressing procedure using aseptic non‐touch technique (ANTT). A team of clinicians, academics, and researchers came together to develop an observational metric using an iterative six‐stage process, culminating in a Delphi panel meeting. A scoping review of the literature provided a background empirical perspective relating to wound‐dressing procedure performance. Video recordings of acute surgical wound‐dressing procedures performed by nurses in clinical (n = 11) and simulated (n = 3) settings were viewed repeatedly and were iteratively deconstructed by the metric development group. This facilitated the identification of the discrete component steps, potential errors, and sentinel (serious) errors, which characterise a wound dressing procedure and formed part of the observational metric. The ANTT wound‐dressing observational metric was stress tested for clarity, the ability to be scored, and interrater reliability, calculated during a further phase of video analysis. The metric was then subjected to a process of cyclical evaluation by a Delphi panel (n = 21) to obtain face and content validity of the metric. The Delphi panel deliberation verified the face and content validity of the metric. The final metric has three phases, 31 individual steps, 18 errors, and 27 sentinel errors. The metric is a tool that identifies the standard to be attained in the performance of acute surgical wound dressings. It can be used as both an adjunct to an educational programme and as a tool to assess a practitioner's performance of a wound‐dressing procedure in both simulated and clinical practice contexts.     

Ca-EGTA affects the relationship between [Ca2+] and tension in α-toxin permeabilized rat anococcygeus smooth muscle

Summary The relationship between calcium concentration ([Ca²⁺]) and force in smooth muscle can be studied by permeabilizing the sarcolemma and bathing the preparation in a mock intracellular solution. Normally [Ca²⁺] is set in these solutions using the Ca²⁺ chelator EGTA in the concentration range of 4–10 mm. This study shows that lowering total EGTA concentration ([EGTA]_t) below 10 mm depresses Ca²⁺-activated force generated in 0.1 m Ca²⁺. The observed threshold for the effect of EGTA_t is 0.2 mm, and the effect is maximal at approximately 10 mm. BAPTA, another Ca²⁺ chelator, also produces this effect. Tension production in smooth muscle is controlled by acto-myosin interaction. This in turn is mediated by the relative activities of myosin light chain kinase (MLCK) and phosphatase (MLCP). Inhibiting MLCP with Microcystin LR (10 m), an increase [EGTA_t] from 0.2 mm to 10 mm still enhanced force. This suggests that EGTA promotes phosphorylation of myosin by the activation of MLCK and not by inhibition of MLCP.     

Dysregulation of dopamine signaling in the dorsal striatum inhibits feeding

Dopamine signaling is an important component of many goal-directed behaviors, such as feeding. Acute disruption of dopamine signaling using pharmacological agents tends to inhibit normal feeding behaviors in rodents. Likewise, genetically engineered dopamine-deficient (DD) mice are unable to initiate sufficient feeding and will starve by approximately 3 weeks of age if untreated. Adequate feeding by DD mice can be achieved by daily administration of L-3,4-dihydroxyphenylalanine (L-dopa), a precursor of dopamine, which can be taken up by dopaminergic neurons, converted to dopamine, and released in a regulated manner. In contrast, adequate feeding cannot be restored with apomorphine (APO), a mixed agonist that activates D1 and D2 receptors. Viral restoration of dopamine production in neurons that project to the dorsal striatum also restores feeding in DD mice. Administration of amphetamine (AMPH) or nomifensine (NOM), drugs which increase synaptic dopamine concentration, inhibits food intake in virally rescued DD mice (vrDD) as in control animals. These results indicate that the dysregulation of dopamine signaling in the dorsal striatum is sufficient to induce hypophagia and suggest that regulated release of dopamine in that brain region is essential for normal feeding and, probably, many other goal-directed behaviors.     

No evidence for association of the dysbindin gene [DTNBP1] with schizophrenia in an Irish population-based study

A recent family-based association study identified a putative association between variants in the dystrobrevin binding protein 1 (dysbindin) gene (DTNBP1) and schizophrenia. This study used a sample of 270 Irish pedigrees multiply affected with schizophrenia. We attempted to replicate these findings in an independent Irish sample of 219 schizophrenia cases and 231 controls. No evidence was found to suggest an association between the DTNBP1 gene and schizophrenia in our sample. Possible reasons for these findings are discussed.     

Neurobehavioral Dynamics Following Chronic Sleep Restriction: Dose-Response Effects of One Night for Recovery

Objective:

Establish the dose-response relationship between increasing sleep durations in a single night and recovery of neurobehavioral functions following chronic sleep restriction.

Design:

Intent-to-treat design in which subjects were randomized to 1 of 6 recovery sleep doses (0, 2, 4, 6, 8, or 10 h TIB) for 1 night following 5 nights of sleep restriction to 4 h TIB.

Setting:

Twelve consecutive days in a controlled laboratory environment.

Participants:

N = 159 healthy adults (aged 22-45 y), median = 29 y).

Interventions:

Following a week of home monitoring with actigraphy and 2 baseline nights of 10 h TIB, subjects were randomized to either sleep restriction to 4 h TIB per night for 5 nights followed by randomization to 1 of 6 nocturnal acute recovery sleep conditions (N = 142), or to a control condition involving 10 h TIB on all nights (N = 17).

Measurements and Results:

Primary neurobehavioral outcomes included lapses on the Psychomotor Vigilance Test (PVT), subjective sleepiness from the Karolinska Sleepiness Scale (KSS), and physiological sleepiness from a modified Maintenance of Wakefulness Test (MWT). Secondary outcomes included psychomotor and cognitive speed as measured by PVT fastest RTs and number correct on the Digit Symbol Substitution Task (DSST), respectively, and subjective fatigue from the Profile of Mood States (POMS). The dynamics of neurobehavioral outcomes following acute recovery sleep were statistically modeled across the 0 h-10 h recovery sleep doses. While TST, stage 2, REM sleep and NREM slow wave energy (SWE) increased linearly across recovery sleep doses, best-fitting neurobehavioral recovery functions were exponential across recovery sleep doses for PVT and KSS outcomes, and linear for the MWT. Analyses based on return to baseline and on estimated intersection with control condition means revealed recovery was incomplete at the 10 h TIB (8.96 h TST) for PVT performance, KSS sleepiness, and POMS fatigue. Both TST and SWE were elevated above baseline at the maximum recovery dose of 10 h TIB.

Conclusions:

Neurobehavioral deficits induced by 5 nights of sleep restricted to 4 h improved monotonically as acute recovery sleep dose increased, but some deficits remained after 10 h TIB for recovery. Complete recovery from such sleep restriction may require a longer sleep period during 1 night, and/or multiple nights of recovery sleep. It appears that acute recovery from chronic sleep restriction occurs as a result of elevated sleep pressure evident in both increased SWE and TST.

Citation:

Banks S; Van Dongen HPA; Maislin G; Dinges DF. Neurobehavioral dynamics following chronic sleep restriction: dose-response effects of one night for recovery. SLEEP 2010;33(8):1013–1026.     

A comprehensive approach to identification of pathogenic FANCA variants in Fanconi anemia patients and their families

Fanconi anemia (FA) is a rare recessive DNA repair deficiency resulting from mutations in one of at least 22 genes. Two‐thirds of FA families harbor mutations in FANCA. To genotype patients in the International Fanconi Anemia Registry (IFAR) we employed multiple methodologies, screening 216 families for FANCA mutations. We describe identification of 57 large deletions and 261 sequence variants, in 159 families. All but seven families harbored distinct combinations of two mutations demonstrating high heterogeneity. Pathogenicity of the 18 novel missense variants was analyzed functionally by determining the ability of the mutant cDNA to improve the survival of a FANCA‐null cell line when treated with MMC. Overexpressed pathogenic missense variants were found to reside in the cytoplasm, and nonpathogenic in the nucleus. RNA analysis demonstrated that two variants (c.522G > C and c.1565A > G), predicted to encode missense variants, which were determined to be nonpathogenic by a functional assay, caused skipping of exons 5 and 16, respectively, and are most likely pathogenic. We report 48 novel FANCA sequence variants. Defining both variants in a large patient cohort is a major step toward cataloging all FANCA variants, and permitting studies of genotype–phenotype correlations.