Decoding brain memory formation by single-cell RNA sequencing.

To understand how distinct memories are formed and stored in the brain is an important and fundamental question in neuroscience and computational biology. A population of neurons, termed engram cells, represents the physiological manifestation of a specific memory trace and is characterized by dynamic changes in gene expression, which in turn alters the synaptic connectivity and excitability of these cells. Recent applications of single-cell RNA sequencing (scRNA-seq) and single-nucleus RNA sequencing (snRNA-seq) are promising approaches for delineating the dynamic expression profiles in these subsets of neurons, and thus understanding memory-specific genes, their combinatorial patterns and regulatory networks. The aim of this article is to review and discuss the experimental and computational procedures of sc/snRNA-seq, new studies of molecular mechanisms of memory aided by sc/snRNA-seq in human brain diseases and related mouse models, and computational challenges in understanding the regulatory mechanisms underlying long-term memory formation.

RNA processing errors triggered by cadmium and integrator complex disruption are signals for environmental stress.

BACKGROUND: Adaptive responses to stress are essential for cell and organismal survival. In metazoans, little is known about the impact of environmental stress on RNA homeostasis. RESULTS: By studying the regulation of a cadmium-induced gene named numr-1 in Caenorhabditis elegans, we discovered that disruption of RNA processing acts as a signal for environmental stress. We find that NUMR-1 contains motifs common to RNA splicing factors and influences RNA splicing in vivo. A genome-wide screen reveals that numr-1 is strongly and specifically induced by silencing of genes that function in basal RNA metabolism including subunits of the metazoan integrator complex. Human integrator processes snRNAs for functioning with splicing factors, and we find that silencing of C. elegans integrator subunits disrupts snRNA processing, causes aberrant pre-mRNA splicing, and induces the heat shock response. Cadmium, which also strongly induces numr-1, has similar effects on RNA and the heat shock response. Lastly, we find that heat shock factor-1 is required for full numr-1 induction by cadmium. CONCLUSION: Our results are consistent with a model in which disruption of integrator processing of RNA acts as a molecular damage signal initiating an adaptive stress response mediated by heat shock factor-1. When numr-1 is induced via this pathway in C. elegans, its function in RNA metabolism may allow it to mitigate further damage and thereby promote tolerance to cadmium.

[Bilateral intracochlear schwannomas in a patient with no genetic or clinical features of neurofibromatosis type 2. German version]. / Bilaterale intracochleäre Schwannome bei einer Patientin ohne genetische oder klinische Hinweise auf Neurofibromatose Typ 2.

Schwannomas of the eighth cranial nerve are benign tumours commonly found in the internal auditory meatus or in the cerebellopontine angle. In most cases, they arise from the inferior or vestibular portion of the vestibular nerve. Rarely, these tumours present in the inner ear and are then called intralabyrinthine schwannomas. Bilateral schwannomas are known in neurofibromatosis type 2 (NF2). Bilateral and ipsilateral, multilocular sporadic schwannomas of the eighth cranial nerve have been described as extremely rare findings. This report describes the first case of bilateral sporadic intracochlear schwannomas in a patient with no genetic or clinical features of NF2.

Bilateral intracochlear schwannomas in a patient with no genetic or clinical features of neurofibromatosis type 2.

Schwannomas of the eighth cranial nerve are benign tumours commonly found in the internal auditory meatus or in the cerebellopontine angle. In most cases, they arise from the inferior or vestibular portion of the vestibular nerve. Rarely, these tumours present in the inner ear and are then called intralabyrinthine schwannomas. Bilateral schwannomas are known in neurofibromatosis type 2 (NF2). Bilateral and ipsilateral, multilocular sporadic schwannomas of the eighth cranial nerve have been described as extremely rare findings. This report describes the first case of bilateral sporadic intracochlear schwannomas in a patient with no genetic or clinical features of NF2.

A population-based study of the association between dysglycaemia and hearing loss in middle age.

AIMS: To investigate the independent associations between hearing loss and dysglycaemia in a sample of middle-aged adults, including separate analysis of those aged < 60 years. METHODS: The first 2023 participants in the cross-sectional Busselton Health Ageing Survey were assessed for hearing loss ≥ 26 dB (better ear) for four-frequency average (4FA) of pure-tone thresholds at 500, 1000, 2000 and 4000 Hz, and high-frequency average (HFA) of pure-tone thresholds at 4000 and 8000 Hz. RESULTS: Valid data from 1864 participants in the Busselton Health Ageing Survey [92.1%; mean ± sd age 56.2 ± 5.5 years, 46.0% men, 120 (7.0%) with diabetes, 274 (14.7%) with prediabetes] were analysed, of whom 103 (5.5%) had four-frequency average hearing loss and 561 (30.1%) had high-frequency average hearing loss. In multivariable analyses, glycaemic status was not independently associated with four-frequency or high-frequency average hearing loss. In the 1286 participants aged < 60 years, there was no relationship between dysglycaemia and high-frequency average hearing loss, but the prevalence of four-frequency average hearing loss increased from 2.3% (95% CI 1.5-3.4) in participants with normoglycaemia to 5.7% (95% CI 3.0-10.6) in those with prediabetes and 10.2% (4.2-21.5) in those with diabetes (trend P = 0.003). In multivariable analysis with normoglycaemia as reference, the odds ratios for four-frequency average hearing loss were 2.84 (95% CI 1.29-6.27) for prediabetes and 5.93 (95% CI 1.67-21.05) for diabetes (P ≤ 0.01) in the < 60 year age group. CONCLUSIONS: There was progressively increasing mid-range hearing loss with worsening glucose tolerance in younger individuals, suggesting dysglycaemia-associated early-onset presbycusis.

Self-reported cochlear implant management skills: development and validation of the self-administered Cochlear Implant Management Skills (CIMS-self) survey.

OBJECTIVE: A self-administered device management survey was developed and validated to investigate the ability of cochlear implant recipients to self-report physical handling and care for their hearing implant device(s) and to identify factors that may influence self-reported management skills. DESIGN: Survey development and validation. A prospective convenience cohort design study. SETTING: Specialist hearing implant clinic. PARTICIPANTS: Forty-nine post-lingually hearing impaired, adult cochlear implant recipients, at least 12 months postoperative. MAIN OUTCOME MEASURES: Survey test-retest reliability, responsiveness, criterion validity and sensitivity and specificity compared to clinician evaluation of device management skills. Correlations between self-reported management skills and participant demographic, audiometric, cognitive function, clinical outcomes and device factors. RESULTS: The self-administered Cochlear Implant Management Skills survey was developed, demonstrating high test-retest reliability (ICC = 0.884, P < 0.001; CI 95%: 0.721-0.952), responsiveness to intervention (management skills training) [t(20) = -3.245, P = 0.004], criterion validity (ICC = 0.765, P < 0.001; CI 95%: 0.584-0.868) and sensitivity (0.89). No associations were found between self-reported management skills and participant factors. CONCLUSIONS: This study demonstrated that a self-report survey is an effective method for the evaluation of skills required for cochlear implant device management.

Protective benefit of predominant breastfeeding against otitis media may be limited to early childhood: results from a prospective birth cohort study.

OBJECTIVES: To examine the long-term effects of predominant breastfeeding on incidence of otitis media. DESIGN: Prospective birth cohort study. SETTING: The West Australian Pregnancy Cohort (Raine) Study recruited 2900 mothers through antenatal clinics at the major tertiary obstetric hospital in Perth, Western Australia, between 1989 and 1992. PARTICIPANTS: In total, 2237 children participated in a 6-year cohort follow-up, and a subset of 1344 were given ear and hearing assessments. MAIN OUTCOME MEASURES: OM diagnosis at 6 years of age (diagnosed by low-compliance tympanograms, 0-0.1 mmho). This was compared to OM diagnosed at the 3-year cohort follow-up using parent-report measures. Main exposure measures were duration of predominant breastfeeding (defined as the age other milk was introduced) and duration of partial (any) breastfeeding (defined as the age breastfeeding was stopped). RESULTS: There was a significant, independent association between predominant breastfeeding (OR = 1.33 [1.04, 1.69]; P = 0.02) and OM, and breastfeeding duration (OR = 1.35 [1.08, 1.68]; P = 0.01) with OM at 3 years of age. However, at 6 years of age, this relationship was no longer statistically significant (predominant breastfeeding OR = 0.78 [0.48, 1.06]; P = 0.09; duration of breastfeeding, OR = 1.34 [0.81, 2.23]; P = 0.25). CONCLUSIONS: Our findings are in line with a number of epidemiological studies which show a positive association between breastfeeding and OM in early childhood. However, the long-term follow-up of these children revealed that by 6 years of age, there was no significant influence of breastfeeding on presence of OM. These results suggest that the protective effect of predominant breastfeeding for at least 6 months does not extend to school-age children, where other social and environmental factors may be stronger predictors of OM.

A prospective study evaluating cochlear implant management skills: development and validation of the Cochlear Implant Management Skills survey.

OBJECTIVE: To investigate the ability of cochlear implant (CI) recipients to physically handle and care for their hearing implant device(s) and to identify factors that may influence skills. To assess device management skills, a clinical survey was developed and validated on a clinical cohort of CI recipients. DESIGN: Survey development and validation. A prospective convenience cohort design study. SETTING: Specialist hearing implant clinic. PARTICIPANTS: Forty-nine post-lingually deafened, adult CI recipients, at least 12 months postoperative. MAIN OUTCOME MEASURES: Survey test-retest reliability, interobserver reliability and responsiveness. Correlations between management skills and participant demographic, audiometric, clinical outcomes and device factors. RESULTS: The Cochlear Implant Management Skills survey was developed, demonstrating high test-retest reliability (0.878), interobserver reliability (0.972) and responsiveness to intervention (skills training) [t(20) = -3.913, P = 0.001]. Cochlear Implant Management Skills survey scores range from 54.69% to 100% (mean: 83.45%, sd: 12.47). No associations were found between handling skills and participant factors. CONCLUSIONS: This is the first study to demonstrate a range in cochlear implant device handling skills in CI recipients and offers clinicians and researchers a tool to systematically and objectively identify shortcomings in CI recipients' device handling skills.

Evidence for gravitational lensing of the cosmic microwave background polarization from cross-correlation with the cosmic infrared background.

We reconstruct the gravitational lensing convergence signal from cosmic microwave background (CMB) polarization data taken by the Polarbear experiment and cross-correlate it with cosmic infrared background maps from the Herschel satellite. From the cross spectra, we obtain evidence for gravitational lensing of the CMB polarization at a statistical significance of 4.0σ and indication of the presence of a lensing B-mode signal at a significance of 2.3σ. We demonstrate that our results are not biased by instrumental and astrophysical systematic errors by performing null tests, checks with simulated and real data, and analytical calculations. This measurement of polarization lensing, made via the robust cross-correlation channel, not only reinforces POLARBEAR auto-correlation measurements, but also represents one of the early steps towards establishing CMB polarization lensing as a powerful new probe of cosmology and astrophysics.

Measurement of the cosmic microwave background polarization lensing power spectrum with the POLARBEAR experiment.

Gravitational lensing due to the large-scale distribution of matter in the cosmos distorts the primordial cosmic microwave background (CMB) and thereby induces new, small-scale B-mode polarization. This signal carries detailed information about the distribution of all the gravitating matter between the observer and CMB last scattering surface. We report the first direct evidence for polarization lensing based on purely CMB information, from using the four-point correlations of even- and odd-parity E- and B-mode polarization mapped over ∼30 square degrees of the sky measured by the POLARBEAR experiment. These data were analyzed using a blind analysis framework and checked for spurious systematic contamination using null tests and simulations. Evidence for the signal of polarization lensing and lensing B modes is found at 4.2σ (stat+sys) significance. The amplitude of matter fluctuations is measured with a precision of 27%, and is found to be consistent with the Lambda cold dark matter cosmological model. This measurement demonstrates a new technique, capable of mapping all gravitating matter in the Universe, sensitive to the sum of neutrino masses, and essential for cleaning the lensing B-mode signal in searches for primordial gravitational waves.

Correlation analysis of ductus venosus velocity indices and fetal cardiac function.

OBJECTIVE: To examine the relationships between the ductus venosus (DV) pulsatility index for veins (PIV), individual DV velocity ratios and diastolic and global myocardial cardiac function. METHODS: Doppler measurements of the DV, atrioventricular (AV) valves and ventricular in- and outflow were analyzed. The DV-PIV and velocity ratios for individual phases (systole (S), end-systolic relaxation (v), early diastole (D), atrial systole (a), and S/v, S/D, S/a, v/D, v/a and D/a ratios) were calculated. The ratio of early and late diastolic peak velocities across AV valves was calculated (E/A ratio). Left modified myocardial performance index (MPI) was calculated from time intervals between valve clicks defining isovolumetric contraction/relaxation and ejection times. All values were transformed to Z-scores. The distributions of DV velocity ratios and DV-PIV were correlated with cardiac Doppler parameters. RESULTS: A total of 1163 examinations from 213 fetuses, most of which were at risk for cardiac dysfunction, were included in the study. In 742 the PIV was normal and in 421 PIV was elevated > 2 SD above the normal mean. The DV-PIV correlated with velocity ratios (P < 0.0001) but not with E/A ratios and the MPI. S/v and v/D ratios were related to tricuspid and mitral E/A ratios and left ventricular MPI. The S/D ratio was only related to both E/A ratios. There was no relationship between a-wave-related velocity ratios and cardiac function. CONCLUSIONS: Velocity ratios of the DV show relationships with cardiac function that are not reflected by the PIV alone. In cases of suspected fetal cardiac dysfunction based on elevated DV-PIV, analysis of velocity ratios or direct cardiac evaluation is suggested to determine the underlying pathophysiology.

Long-term quality of life in patients with vestibular schwannoma managed with microsurgery.

OBJECTIVE: Little is known about the long term (greater than 10 years) quality of life in patients with vestibular schwannoma. This study aimed to evaluate long-term outcomes in patients with vestibular schwannoma. METHOD: A retrospective cohort study was performed across 2 academic institutions, with patients followed at least 10 years after vestibular schwannoma surgery (2000 to 2007). Telephone interviews were used to assess quality of life using the Glasgow Benefit Inventory and short form 12 item (version 2) health survey. RESULTS: A total of 99 out of 110 patients were included. Increasing age and symptom burden were associated with poorer quality of life (p = 0.01 and 0.02, respectively). The presence of imbalance, headache and facial nerve dysfunction were all associated with poorer quality of life scores (p = 0.01, 0.04 and 0.02, respectively). CONCLUSION: Identifying and managing post-operative symptoms may improve quality of life in vestibular schwannoma patients and can guide clinical decision making.

Utilization of fresh human tympanic membranes for structural analysis and cytokeratin immunocytochemistry implementing resin techniques.

CONCLUSIONS: The results of this study have demonstrated for the first time that tympanic membrane (TM) structure is preserved following removal of fresh, normal tissue from patients undergoing surgery. Greater clarity has been demonstrated using resin sections than in previous studies on paraffin sections. Of particular note, cytokeratin (CK) immunocytochemistry was successfully performed on resin sections, which has not been previously reported. This may have potential applications for future work involving tissues that express CKs. OBJECTIVES: To analyse the structure of normal, fresh human TM specimens after surgical removal and to evaluate their CK immunocytochemistry using resin techniques, neither of which have been demonstrated previously. MATERIAL AND METHODS: Seven TM specimens were removed during surgery and then preserved in a modified Karnovsky's fixative. Semi-thin and thin sections were examined by means of light and electron microscopy, respectively. For comparison purposes, paraffin block-embedded specimens were also sectioned. CK immunocytochemistry was performed on semi-thin sections using standard immunoperoxidase techniques, with expression being demonstrated using light microscopy. RESULTS: The three-layer architecture of the TM was preserved. The morphology of the TM was vastly superior in the semi-thin resin sections than in the thicker paraffin sections. The outer, middle and inner layers were clearly demonstrated. The integrity of the outer epithelial layer was maintained, with an outer keratinizing stratum corneum and underlying stratum granulosum, stratum spinosum and stratum basale layers resting on the basal lamina. The thin inner mucosal layer was also viable, consisting of simple squamous or cuboidal cells. Preservation of the middle lamina propria was achieved, with demonstration of the outer radial and inner circular fibres. CK immunocytochemistry utilizing resin techniques provided excellent staining of CK 7 and 8 in the inner layer, with positive staining of CK 5 and 10 in the outer layer.

Simultaneous cochlear implantation and labyrinthectomy for advanced Ménière's disease.

BACKGROUND: Patients with Ménière's disease can develop unaidable sensorineural hearing loss. Cochlear implantation has recently been utilised in this group with favourable results. A more challenging group are those with intractable vertigo, and they have traditionally posed a significant management dilemma. CASE REPORT: Two female patients with unaidable hearing and recurrent incapacitating vertigo attacks despite conservative management underwent simultaneous labyrinthectomy and cochlear implantation. There was complete resolution of vertigo in both patients. Speech perception in quiet conditions and the ability to hear in background noise improved considerably. CONCLUSION: Surgical labyrinthectomy is effective for the elimination of vertigo in Ménière's disease patients. The major disadvantage in the past was loss of residual hearing. Cochlear implantation is now an option in these patients. The benefits of simultaneous labyrinthectomy with cochlear implantation include the prevention of implantation of a fibrosed or ossified cochlea, a decrease in the duration of deafness, and a single operative procedure.

The role of subtotal petrosectomy in cochlear implantation.

BACKGROUND: Subtotal petrosectomy combined with cochlear implantation is a procedure required in specific situations. METHODS: A retrospective review of all cases of subtotal petrosectomy in cochlear implant surgery over a five-year period was performed. The indications, complications and outcomes for this procedure are outlined. RESULTS: Sixteen patients underwent cochlear implantation in combination with subtotal petrosectomy and blind sac closure of the external auditory meatus from 2008 to 2013. Seventy-five per cent of these were completed as a two-stage procedure and 25 per cent as a single-stage procedure. The most common indications for the procedure were chronic otitis media, previous radical cavity, and for surgical access in challenging anatomy or in drill-out procedures. Mastoids were obliterated with fat or musculoperiosteal flaps. The complication rate relating to blind sac closure was 6 per cent. Cochlear implants were successfully placed in all cases and there was no incidence of device failure. CONCLUSION: For patients with chronic suppurative otitis media or existing mastoid cavities, subtotal petrosectomy with blind sac closure of the external auditory canal, closure of the eustachian tube, and cavity obliteration is an effective technique to facilitate safe cochlear implantation.

Importance of the duration of inadequate coronary perfusion pressure on resuscitation from cardiac arrest.

The effect of the duration of inadequate coronary perfusion pressure on resuscitation from cardiac arrest was examined in 32 mongrel dogs with a mean weight of 22 +/- 5 kg. In all dogs, the heart was electrically fibrillated and closed chest compression with assisted ventilation was performed for 15 minutes. At this time, all dogs had an inadequate coronary perfusion pressure (mean 7 +/- 9 mm Hg) and were randomized to a control group (group 1) with continued closed chest compression or to one of the three groups with open chest cardiac massage. These three groups differed only in the duration of continued closed chest compression before initiation of open chest massage (15, 20 and 25 minutes, respectively, in groups 2, 3 and 4). The control group (group 1) had no significant increase in coronary perfusion pressure, and only one of the eight dogs could be resuscitated. The three groups with open chest cardiac massage had a significant increase in coronary perfusion pressure (from 5 +/- 9 to 51 +/- 26 mm Hg, p less than 0.05), but the rate of successful resuscitation depended on the duration of inadequate coronary perfusion pressure before cardiac open chest massage. In group 2, six of eight dogs were resuscitated (p less than 0.05 compared with the control group); in group 3, three of eight dogs were resuscitated and in group 4 none of the eight dogs was resuscitated. The resuscitation rate was significantly (p less than 0.05) greater in group 2 than in group 4. These findings indicate that techniques that improve coronary perfusion pressure during cardiopulmonary resuscitation must be applied before extensive myocardial cellular dysfunction occurs if the probability of successful resuscitation is to be improved.

Molecular analysis of 13 cases of MLL/11q23 secondary acute leukemia and identification of topoisomerase II consensus-binding sequences near the chromosomal breakpoint of a secondary leukemia with the t(4;11).

Rearrangements of the MLL (Mixed Lineage Leukemia) gene in the human 11q23 cytogenetic locus have been detected in secondary (therapy-related) acute leukemias in patients who have received topoisomerase II inhibitors for prior, independent neoplasms. The topoisomerase II inhibitors implicated in MLL/11q23 secondary leukemias all inhibit the religation step of reaction catalyzed by topoisomerase II. This results in the stabilization of a 'cleavable complex' with double-strand DNA breaks at the point of topoisomerase II binding. This raises the possibility that the cleavable complex participates in the translocation process in MLL/11q23 secondary leukemias. Here we report that the MLL/11q23 breakpoints in 13/13 patients with secondary leukemia map to the same breakpoint cluster region (bcr) noted in de novo MLL/11q23 acute leukemias and the presence of in vivo topoisomerase II inhibitor-induced cleavage sites in MLL/11q23 bcr. We have also cloned and sequenced the breakpoint from a MLL/11q23 secondary acute leukemia. This analysis revealed sequences similar to the consensus sequence for vertebrate topoisomerase II binding and cleavage close to the 11q23 and 4q21 breakpoints. These results support a role for topoisomerase II in mechanism generating translocations in MLL/11q23 secondary acute leukemia.

Cloning and sequence analysis of four t(9;11) therapy-related leukemia breakpoints.

The t(9;11)(p22;q23) is the most common chromosomal translocation in topoisomerase II inhibitor therapy-related acute myeloid leukemia (tAML). This translocation fuses the MLL and AF9 proto-oncogenes producing a novel chimeric protein. In order to gain insight into the mechanism generating the t(9;11) and to clarify the role topoisomerase II inhibition may play in that mechanism we have cloned and sequenced the breakpoints from four tAML patients with the t(9;11). This sequence analysis identifies topoisomerase II consensus binding sequences near or at the chromosome 11 and chromosome 9 breakpoints in all four patients. One patient also had the consensus binding sequence for the TRANSLIN DNA-binding protein at the 9p22 and 11q23 breakpoints. Our results further support a direct role for topoisomerase II in the genesis of these tAML translocations.

Metastatic congenital adrenocortical carcinoma: a case report with tumor remission at 3 1/2 years.

We describe a case of metastasizing congenital adrenocortical carcinoma and a follow-up of 3 1/2 yr. Treatment with surgery and mitotane was associated with multiple complications. The patient was in remission at 3 1/2 yr. Because of the rarity of this condition, we discuss step-by-step problems encountered during management.

A new technique for hypoglossal-facial nerve repair.

Hypoglossal reinnervation of the facial nerve may be required after a proximal facial nerve injury. The classic hypoglossal-facial graft procedure involves transection of the donor hypoglossal nerve, resulting in hemiglottic paralysis that, in association with paralysis of other cranial nerves, may cause speech and swallowing difficulties. Multiple lower cranial nerve palsies in conjunction with facial paralysis, as may occur after procedures such as skull base surgery, contraindicate the use of such techniques. The successful use of XII-VII "interposition jump grafts" without hemiglossal weakness has been described However, a prolonged recovery period and weaker facial reanimation have been seen. In order to attain maximum facial reinnervation while preserving hypoglossal function, we have developed a new technique of XII-VII repair. This method involves mobilization of the intratemporal portion of the facial nerve remnant, achieving a single anastomosis with the hypoglossal nerve, which has been partially incised. This technique has been used in three patients to date, with 6 to 11 months follow-up. In all cases facial tone and symmetry have been restored and voluntary facial expression accomplished. The authors conclude that by employing the techniques described highly satisfactory cosmetic and functional results may be expected, without compromising hypoglossal nerve function.