Patient and Caregiver Perceptions of Airway Clearance Methods Used for Cystic Fibrosis

Introduction

Cystic Fibrosis Foundation guidelines recommend people with CF perform daily airway clearance. This can be difficult for patients, as some find it time consuming or uncomfortable. Data comparing airway clearance methods are limited. We surveyed patients and their families to understand which methods are preferred and identify obstacles to performing airway clearance.

Methods

We designed a REDCap survey and enrolled participants in 2021. Respondents reported information on airway clearance usage, time commitment, and medication use. They rated airway clearance methods for effectiveness, comfort, time commitment, importance, and compatibility with other treatments. The analysis included descriptive statistics and clustering.

Results

60 respondents started and 52 completed the survey. The median patient age was 20 years. Respondents experienced a median of four airway clearance methods in their lifetime, including chest wall oscillation (vest, 92%), manual chest physical therapy (CPT, 88%), forced expiration technique (huff or cough, 77%), and exercise (75%). Past 30-day use was highest for exercise (62%) and vest (57%). The time commitment was generally less than 2 hours daily. Of those eligible for CFTR modulators, 53% reported decreased time commitment to airway clearance after starting treatment. On a scale of 0-100, respondents rated CFTR modulators as their most important treatment (median 99.5), followed by exercise (88). Discussion. Patients and caregivers are familiar with several methods of airway clearance for CF. They report distinct strengths and limitations of each method. Exercise and vest are the most common methods of airway clearance. The use of CFTR modulators may reduce patient-reported time commitment to airway clearance.

RNASE6 is a novel modifier of APOE-ε4 effects on cognition

Apolipoprotein E4 (APOE-ε4), the strongest common genetic risk factor for Alzheimer's disease (AD), contributes to worse cognition in older adults. However, many APOE-ε4 carriers remain cognitively normal throughout life, suggesting that neuroprotective factors may be present in these individuals. In this study, we leverage whole-blood RNA sequencing (RNAseq) from 324 older adults to identify genetic modifiers of APOE-ε4 effects on cognition. Expression of RNASE6 interacted with APOE-ε4 status (p = 4.35 × 10^-8) whereby higher RNASE6 expression was associated with worse memory at baseline among APOE-ε4 carriers. This interaction was replicated using RNAseq data from the prefrontal cortex in an independent dataset (N = 535; p = 0.002), suggesting the peripheral effect of RNASE6 is also present in brain tissue. RNASE6 encodes an antimicrobial peptide involved in innate immune response and has been previously observed in a gene co-expression network module with other AD-related inflammatory genes, including TREM2 and MS4A. Together, these data implicate neuroinflammation in cognitive decline, and suggest that innate immune signaling may be detectable in blood and confer differential susceptibility to AD depending on APOE-ε4.

Protective genes and pathways in Alzheimer's disease: moving towards precision interventions

Alzheimer's disease (AD) is a progressive, neurodegenerative disorder that is characterized by neurodegeneration, cognitive impairment, and an eventual inability to perform daily tasks. The etiology of Alzheimer's is complex, with numerous environmental and genetic factors contributing to the disease. Late-onset AD is highly heritable (60 to 80%), and over 40 risk loci for AD have been identified via large genome-wide association studies, most of which are common variants with small effect sizes. Although these discoveries have provided novel insight on biological contributors to AD, disease-modifying treatments remain elusive. Recently, the concepts of resistance to pathology and resilience against the downstream consequences of pathology have been of particular interest in the Alzheimer's field as studies continue to identify individuals who evade the pathology of the disease even into late life and individuals who have all of the neuropathological features of AD but evade downstream neurodegeneration and cognitive impairment. It has been hypothesized that a shift in focus from Alzheimer's risk to resilience presents an opportunity to uncover novel biological mechanisms of AD and to identify promising therapeutic targets for the disease. This review will highlight a selection of genes and variants that have been reported to confer protection from AD within the literature and will also discuss evidence for the biological underpinnings behind their protective effect with a focus on genes involved in lipid metabolism, cellular trafficking, endosomal and lysosomal function, synaptic function, and inflammation. Finally, we offer some recommendations in areas where the field can rapidly advance towards precision interventions that leverage the ideas of protection and resilience for the development of novel therapeutic strategies.

Inactivation of CFTR by CRISPR/Cas9 alters transcriptional regulation of inflammatory pathways and other networks

BACKGROUND

Individuals with cystic fibrosis (CF) experience elevated inflammation in multiple organs, but whether this reflects an inherent feature of CF cells or is a consequence of a pro-inflammatory environment is not clear.

METHOD

Using CRISPR/Cas9-mediated mutagenesis of CFTR, 17 subclonal cell lines were generated from Caco-2 cells. Clonal lines with functional CFTR (CFTR⁺) were compared to those without (CFTR^-) to directly address the role of CFTR in inflammatory gene regulation.

RESULTS

All lines maintained CFTR mRNA production and formation of tight junctions. CFTR⁺ lines displayed short circuit currents in response to forskolin, while the CFTR^- lines did not. Baseline expression of cytokines IL6 and CXCL8 (IL8) was not different between the lines regardless of CFTR genotype. All lines responded to TNFα and IL1β by increasing IL6 and CXCL8 mRNA levels, but the CFTR^- lines produced more CXCL8 mRNA than the CFTR⁺ lines. Transcriptomes of 6 CFTR^- and 6 CFTR⁺ lines, before and after stimulation by TNFα, were compared for differential expression as a function of CFTR genotype. While some genes appeared to be differentially expressed simply because of CFTR's absence, others required stimulation for differences to be apparent.

CONCLUSION

Together, these data suggest cells respond to CFTR's absence by modulating transcriptional networks, some of which are only apparent when cells are exposed to different environmental contexts, such as inflammation. With regards to inflammation, these data suggest a model in which CFTR's absence leads to a poised, pro-inflammatory state of cells that is only revealed by stimulation.

Ccl5 Mediates Proper Wiring of Feedforward and Lateral Inhibition Pathways in the Inner Retina

The β-chemokine Ccl5 and its receptors are constitutively expressed in neurons of the murine inner retina. Here, we examined the functional and structural significance of this constitutive Ccl5 signaling on retinal development. We compared outcomes of electrophysiology, ocular imaging and retinal morphology in wild-type mice (WT) and mice with Ccl5 deficiency (Ccl5^-/-). Assessment of retinal structure by ocular coherence tomography and histology revealed slight thinning of the inner plexiform layer (IPL) and inner nuclear layer (INL) in Ccl5^-/- mice, compared to WT (p < 0.01). Assessment of postnatal timepoints important for development of the INL (P7 and P10) revealed Ccl5-dependent alterations in the pattern and timing of apoptotic pruning. Morphological analyses of major inner retinal cell types in WT, Ccl5^-/-, gustducin^gfp and gustducin^gfp/Ccl5^-/- mice revealed Ccl5-dependent reduction in GNAT3 expression in rod bipolar cells as well as a displacement of their terminals from the IPL into the GCL. RGC dendritic organization and amacrine cell morphology in the IPL was similarly disorganized in Ccl5^-/- mice. Examination of the intrinsic electrophysiological properties of RGCs revealed higher spontaneous activity in Ccl5^-/- mice that was characterized by higher spiking frequency and a more depolarized resting potential. This hyperactive phenotype could be negated by current clamp and correlated with both membrane resistance and soma area. Overall, our findings identify Ccl5 signaling as a mediator of inner retinal circuitry during development of the murine retina. The apparent role of Ccl5 in retinal development further supports chemokines as trophic modulators of CNS development and function that extends far beyond the inflammatory contexts in which they were first characterized.

Wireless high-frequency dorsal root ganglion stimulation for chronic low back pain: A pilot study

OBJECTIVE

Evaluation of the efficacy of a wireless high-frequency stimulator placed over selected DRG of exiting nerve roots for the treatment of chronic low back pain.

DESIGN

Feasibility.

SUBJECTS

Six subjects with chronic, intractable back pain refractory to standard medical treatment.

METHODS

Four stimulators (Freedom-4A) provided by Stimwave Technologies, were implanted over the DRG exiting nerve roots, bilaterally at both the T9 and L2 vertebral levels. Subjects were asked to evaluate stimulation independently with the devices turned on at T9 and subsequently L2 for each of 2 weeks. Subjects were then monitored for 8 weeks with the preferred stimulator. Pain reduction with the Visual Analog Scale (VAS), functionality with the Oswestry Disability Index (ODI), Patient Global Impression of Change (PGIC) and medication usage were evaluated.

RESULTS

Four subjects preferred T9 stimulation with only one subject preferring stimulation at L2. One subject dropped out of the study before conclusion of the 4-week evaluation and is not included in this report. Average pain levels (n = 5) at 12-week post-implantation decreased with 61% for back pain and 56% for leg pain with a significant reduction in pain medication, including a 100% reduction in opioid pain medications. The average reduction in disability was 12%. Subjects reported an average impression of change of 6 (1 = no change, 7 = great deal better).

CONCLUSIONS

Wireless high-frequency stimulation of the DRG is a viable option to treat chronic low back pain. Preliminary results show a subject preference for stimulation at the T9 vertebral level.

Pretreatment with Human Chorionic Gonadotropin Protects the Neonatal Brain against the Effects of Hypoxic-Ischemic Injury

INTRODUCTION

Though the human fetus is exposed to placentally derived human chorionic gonadotropin (hCG) throughout gestation, the role of hCG on the fetal brain is unknown. Review of the available literature appears to indicate that groups of women with higher mean levels of hCG during pregnancy tend to have offspring with lower cerebral palsy (CP) risk. Given that newborn cerebral injury often precedes the development of CP, we aimed to determine whether hCG may protect against the neurodegenerative effects of neonatal brain injury.

METHODS

We utilized the Rice-Vannucci model of neonatal cerebral hypoxia-ischemia (HI) in postnatal day 7 mice to examine whether intraperitoneal administration of hCG 15-18 h prior, 1 h after or immediately following HI decrease brain tissue loss 7 days after injury. We next studied whether hCG has pro-survival and trophic properties in neurons by exposing immature cortical and hippocampal neurons to hCG in vitro and examining neurite sprouting and neuronal survival prior and after glutamate receptor-mediated excitotoxic injury.

RESULTS

We found that intraperitoneal injection of hCG 15 h prior to HI, but not at or 1 h after HI induction, resulted in a significant decrease in hippocampal and striatal tissue loss 7 days following brain injury. Furthermore, hCG reduced N-methyl-d-aspartate (NMDA)-mediated neuronal excitotoxicity in vitro when neurons were continuously exposed to this hormone for 10 days or when given at the time and following neuronal injury. In addition, continuous in vitro administration of hCG for 6-9 days increased neurite sprouting and basal neuronal survival as assessed by at least a 1-fold increase in MAP2 immunoreactivity and a 2.5-fold increase in NeuN + immunoreactivity.

CONCLUSION

Our findings suggest that hCG can decrease HI-associated immature neural degeneration. The mechanism of action for this neuroprotective effect may partly involve inhibition of NMDA-dependent excitotoxic injury. This study supports the hypothesis that hCG during pregnancy has the potential for protecting the developing brain against HI, an important CP risk factor.

Discovery of a novel 2,4-dimethylquinoline-6-carboxamide M4 positive allosteric modulator (PAM) chemotype via scaffold hopping

This Letter details our efforts to replace the 3-amino moiety, an essential pharmacophore for M₄ PAM activity in most M₄ PAMs to date, within the thieno[2,3-b]pyridine core, as the β-amino carboxamide motif has been shown to engender poor solubility, varying degrees of P-gp efflux and represents a structural alert. A scaffold hopping exercise identified a novel 2,4-dimethylquinoline carboxamide core that provided M₄ PAM activity and good CNS penetration without an amino moiety. In addition, MacMillan photoredox catalysis chemistry was essential for construction of the 2,4-dimethylquinoline core.

Discovery of a novel, CNS penetrant M4 PAM chemotype based on a 6-fluoro-4-(piperidin-1-yl)quinoline-3-carbonitrile core

This Letter details the discovery and subsequent optimization of a novel M4 PAM scaffold based on an 6-fluoro-4-(piperidin-1-yl)quinoline-3-carbonitrile core, which represents a distinct departure from the classical M4 PAM chemotypes. Optimized compounds in this series demonstrated improved M4 PAM potency on both human and rat M4 (4 to 5-fold relative to HTS hit), and displayed attractive physicochemical and DMPK profiles, including good CNS penetration (rat brain:plasma Kp=5.3, Kp,uu=2.4; MDCK-MDR1 (P-gp) ER=1.1).

Design and Synthesis of mGlu2 NAMs with Improved Potency and CNS Penetration Based on a Truncated Picolinamide Core

Herein, we detail the optimization of the mGlu₂ negative allosteric modulator (NAM), VU6001192, by a reductionist approach to afford a novel, simplified mGlu₂ NAM scaffold. This new chemotype not only affords potent and selective mGlu₂ inhibition, as exemplified by VU6001966 (mGlu₂ IC₅₀ = 78 nM, mGlu₃ IC₅₀ > 30 μM), but also excellent central nervous system (CNS) penetration (K_p = 1.9, K_p,uu = 0.78), a feature devoid in all previously disclosed mGlu₂ NAMs (K_ps ≈ 0.3, K_p,uus ≈ 0.1). Moreover, this series, based on overall properties, represents an exciting lead series for potential mGlu₂ PET tracer development.

Design and Synthesis of N-Aryl Phenoxyethoxy Pyridinones as Highly Selective and CNS Penetrant mGlu3 NAMs

Herein, we detail the optimization of the mGlu₃ NAM, VU0650786, via a reductionist approach to afford a novel, simplified mGlu₃ NAM scaffold that engenders potent and selective mGlu₃ inhibition (mGlu₃ IC₅₀ = 245 nM, mGlu₂ IC₅₀ > 30 μM) with excellent central nervous system penetration (rat brain/plasma K_p = 1.2, K_p,uu = 0.40). Moreover, this new chemotype, exemplified by VU6010572, requires only four synthetic steps and displays improved physiochemical properties and in vivo efficacy in a mouse tail suspension test (MED = 3 mg/kg i.p.).

Discovery and optimization of 3-(4-aryl/heteroarylsulfonyl)piperazin-1-yl)-6-(piperidin-1-yl)pyridazines as novel, CNS penetrant pan-muscarinic antagonists

This letter describes the synthesis and structure activity relationship (SAR) studies of structurally novel M4 antagonists, based on a 3-(4-aryl/heteroarylsulfonyl)piperazin-1-yl)-6-(piperidin-1-yl)pyridazine core, identified from a high-throughput screening campaign. A multi-dimensional optimization effort enhanced potency at human M4 (hM4 IC50s<200nM), with only moderate species differences noted, and with enantioselective inhibition. Moreover, CNS penetration proved attractive for this series (rat brain:plasma Kp=2.1, Kp,uu=1.1). Despite the absence of the prototypical mAChR antagonist basic or quaternary amine moiety, this series displayed pan-muscarinic antagonist activity across M1-5 (with 9- to 16-fold functional selectivity at best). This series further expands the chemical diversity of mAChR antagonists.

Challenges in the development of an M4 PAM preclinical candidate: The discovery, SAR, and in vivo characterization of a series of 3-aminoazetidine-derived amides

This letter details the continued chemical optimization of a novel series of M4 positive allosteric modulators (PAMs) based on a 5-amino-thieno[2,3-c]pyridazine core by incorporating a 3-amino azetidine amide moiety. The analogs described within this work represent the most potent M4 PAMs reported for this series to date. The SAR to address potency, clearance, subtype selectivity, CNS exposure, and P-gp efflux are described. This work culminated in the discovery of VU6000918, which demonstrated robust efficacy in a rat amphetamine-induced hyperlocomotion reversal model at a minimum efficacious dose of 0.3mg/kg.

Synthesis and evaluation of 4,6-disubstituted pyrimidines as CNS penetrant pan-muscarinic antagonists with a novel chemotype

This letter describes the synthesis and structure activity relationship (SAR) studies of structurally novel M₄ antagonists, based on a 4,6-disubstituted core, identified from a high-throughput screening campaign. A multi-dimensional optimization effort enhanced potency at both human and rat M₄ (IC₅₀s<300nM), with no substantial species differences noted. Moreover, CNS penetration proved attractive for this series (brain:plasma K_p,uu=0.87), while other DMPK attributes were addressed in the course of the optimization effort, providing low in vivo clearance in rat (CL_p=5.37mL/min/kg). Surprisingly, this series displayed pan-muscarinic antagonist activity across M_1-5, despite the absence of the prototypical basic or quaternary amine moiety, thus offering a new chemotype from which to develop a next generation of pan-muscarinic antagonist agents.

Discovery of VU0467485/AZ13713945: An M4 PAM Evaluated as a Preclinical Candidate for the Treatment of Schizophrenia

Herein, we report the structure-activity relationships within a series of potent, selective, and orally bioavailable muscarinic acetylcholine receptor 4 (M₄) positive allosteric modulators (PAMs). Compound 6c (VU0467485) possesses robust in vitro M₄ PAM potency across species and in vivo efficacy in preclinical models of schizophrenia. Coupled with an attractive DMPK profile and suitable predicted human PK, 6c (VU0467485) was evaluated as a preclinical development candidate.

Challenges in the development of an M4 PAM in vivo tool compound: The discovery of VU0467154 and unexpected DMPK profiles of close analogs

This letter describes the chemical optimization of a novel series of M4 positive allosteric modulators (PAMs) based on a 5-amino-thieno[2,3-c]pyridazine core, developed via iterative parallel synthesis, and culminating in the highly utilized rodent in vivo tool compound, VU0467154 (5). This is the first report of the optimization campaign (SAR and DMPK profiling) that led to the discovery of VU0467154, and details all of the challenges faced in allosteric modulator programs (steep SAR, species differences in PAM pharmacology and subtle structural changes affecting CNS penetration).

Peripheral neurostimulation for control of intractable occipital neuralgia

Objective. To present a novel approach for treatment of intractable occipital neuralgia using percutaneous peripheral nerve electrostimulation techniques. Methods. Thirteen patients underwent 17 implant procedures for medically refractory occipital neuralgia. A subcutaneous electrode placed transversely at the level of C1 across the base of the occipital nerve trunk produced paresthesias and pain relief covering the regions of occipital nerve pain Results. With follow-up ranging from 1-½ to 6 years, 12 patients continue to report good to excellent response with greater than 50% pain control and requiring little or no additional medications. The 13th patient (first in the series) was subsequently explanted following symptom resolution. Conclusions. In patients with medically intractable occipital neuralgia, peripheral nerve electrostimulation subcutaneously at the level of C1 appears to be a reasonable alternative to more invasive surgical procedures following failure of more conservative therapies.

Occipital neurostimulation for treatment of intractable headache syndromes

Intractable migraine and other headache syndromes affect almost 40 million Americans and many more millions worldwide. Although many treatment protocols exist, mainly designed around medication regimens, there are estimated to be at least 3-5% of these headache sufferers that do not respond in a meaningful way to medications and whose lives can be severely restricted to darkened, quiet rooms, heavy doses of narcotics, failed personal relationships and an overwhelming sense of hopelessness. In this article, we describe current neuromodulation-based approach to the management of intractable headache.

The future of peripheral nerve neurostimulation

Electrical stimulation of selected peripheral nerves for treatment of intractable pain has been used inconsistently over the past 30 years due to difficulties in clarifying appropriate indications, utilizing approved device technology, and standardizing the surgical techniques. Circumferential electrodes treating mononeuropathies have given way to paddle electrode techniques and, most recently, the application of percutaneous wire electrode methods will allow for minimally invasive peripheral nerve stimulation for certain intractable CRPS and other painful monoeuropathies.

Stereotastic radiosurgery for glomus jugulare tumors

OBJECTIVES/HYPOTHESIS

Surgery is considered to be the mainstay of treatment for glomus jugulare tumors. A subset of patients are poor surgical candidates based on age, medical problems, tumor size, or prior treatment failure. The purpose of this study was to review our results with stereotactic radiosurgery (gamma knife treatment) in this group of patients, with particular attention to adverse reactions and symptom relief.

STUDY DESIGN

Retrospective review and phone survey.

METHODS

Charts were reviewed for size and location of tumor, history of previous treatment, symptoms before and after treatment, amount of radiation received, acute and late complications, and functional level before and after treatment. Pre-treatment and posttreatment magnetic resonance imaging scans were also reviewed. Identified patients were then contacted for a phone interview.

RESULTS

Eight patients were identified. Phone interviews were conducted with four patients. Four patients had failed previous treatment. Follow-up ranged from 7 to 104 months. One patient experienced an acute complication: intractable vertigo requiring hospitalization. No patient experienced delayed cranial neuropathies. No patient reported worsening of any of the following symptoms: pulsatile tinnitus, hearing loss, facial weakness, hoarseness, or difficulty swallowing. Three patients reported improvement in their pulsatile tinnitus. Two patients reported improvement in hearing loss, and one patient each reported improvement in vertigo and difficulty swallowing.

CONCLUSIONS

Preliminary results suggest that stereotactic radiosurgery is useful to control symptoms and may be delivered safely in patients with primary or recurrent glomus jugulare tumors who are poor surgical candidates.

Prospective, multicenter study of spinal cord stimulation for relief of chronic back and extremity pain

STUDY DESIGN

This prospective, multicenter study was designed to investigate the efficacy and outcome of spinal cord stimulation using a variety of clinical and psychosocial outcome measures. Data were collected before implantation and at regular intervals after implantation. This report focuses on 70 patients who had undergone 1 year of follow-up treatment at the time of data analysis.

OBJECTIVES

To provide a more generalizable assessment of long-term spinal cord stimulation outcome by comparing a variety of pain and functional/quality-of-life measures before and after management. This report details results after 1 year of stimulation.

SUMMARY OF BACKGROUND DATA

The historically diverse methods, patient selection criteria, and outcome measures reported in the spinal cord stimulation literature have made interpretation and comparison of results difficult. Although short-term outcomes are generally consistent, long-term outcomes of spinal cord stimulation, as determined by prospective studies that assess multidimensional aspects of the pain complaint among a relatively homogeneous population, are not well established.

METHODS

Two hundred nineteen patients were entered at six centers throughout the United States. All patients underwent a trial of stimulation before implant of the permanent system. Most were psychologically screened. One hundred eighty-two patients were implanted with a permanent stimulating system. At the time of this report, complete 1-year follow-up data were available on 70 patients, 88% of whom reported pain in the back or lower extremities. Patient evaluation of pain and functional levels was completed before implantation and 3, 6, 12, and 24 months after implantation. Complications, medication usage, and work status also were monitored.

RESULTS

All pain and quality-of-life measures showed statistically significant improvement during the treatment year. These included the average pain visual analogue scale, the McGill Pain Questionnaire, the Oswestry Disability Questionnaire, the Sickness Impact Profile, and the Back Depression Inventory. Overall success of the therapy was defined as at least 50% pain relief and patient assessment of the procedure as fully or partially beneficial and worthwhile. Using this definition, spinal cord stimulation successfully managed pain in 55% of patients on whom 1-year follow-up is available. Complications requiring surgical intervention were reported by 17% (12 of 70) of patients. Medication usage and work status were not changed significantly.

CONCLUSIONS

This prospective, multicenter study confirms that spinal cord stimulation can be an effective therapy for management of chronic low back and extremity pain. Significant improvements in many aspects of the pain condition were measured, and complications were minimal.

Targeted expression of a dominant-negative FGF receptor mutant in the epidermis of transgenic mice reveals a role of FGF in keratinocyte organization and differentiation

In this study we used a dominant-negative FGF receptor mutant to block FGF function in a specific tissue of transgenic mice. The mutant receptor, which is known to block signal transduction in cells when co-expressed with wild-type receptors, was targeted to suprabasal keratinocytes using a keratin 10 promoter. The transgene was expressed specifically in the skin and highest expression levels were found in the tail. Expression of the mutant receptor disrupted the organization of epidermal keratinocytes, induced epidermal hyperthickening and resulted in an aberrant expression of keratin 6. This suggests that FGF is essential for the morphogenesis of suprabasal keratinocytes and for the establishment of the normal program of keratinocyte differentiation. Our study demonstrates that dominant-negative growth factor receptors can be used to block selectively the action of a growth factor in specific tissues of transgenic mice.

Hemispheric disconnection syndrome persisting after anterior cerebral artery aneurysm rupture

Hemispheric disconnection syndrome is a rarely reported sequela of aneurysm rupture. Serial neurobehavioral examinations of such a patient after clipping of a right pericallosal artery that had bled into a large portion of the corpus callosum disclosed defects in interhemispheric transfer of information and competitive movements between the left and right extremities. Although the patient's postoperative memory deficit subsequently resolved, his disconnection syndrome persisted and was primarily responsible for his disability despite otherwise normal neurological findings. We studied a second patient with a hematoma in the genu of the corpus callosum secondary to an arteriovenous malformation (AVM). Although the second patient also exhibited postoperative memory problems, her hemispheric disconnection symptoms were minimal and commensurate with a more circumscribed corpus callosum lesion. Neurobehavioral sequelae of aneurysm or AVM rupture involving the anterior circulation, which may be overlooked in the absence of a detailed examination, can produce persistent disability in many patients.

Reconstruction of the anterior skull base following craniofacial resection

Reconstruction of the anterior skull base (ASB) following craniofacial resection must seal off the cranial cavity from the upper respiratory tract and provide structural support for the brain. The inferiorly based pericranial flap is strong, pliable, and well vascularized and is especially suited for reconstruction of small-to moderate-sized midline defects of the ASB. Surgical technique of pericranial flap reconstruction used in three cases is described. Indications for this flap and other types of reconstruction are discussed and compared. We believe pericranial flap reconstruction of the ASB is technically easy, cosmetically acceptable, and safe.

Magnetic resonance imaging and computerized tomography in relation to the neurobehavioral sequelae of mild and moderate head injuries

Twenty patients admitted for minor or moderate closed-head injury were studied to investigate the relationship between magnetic resonance imaging (MRI) and neurobehavioral sequelae. The MRI scans demonstrated 44 more intracranial lesions than did concurrent computerized tomography (CT) scans in 17 patients (85%); most of these lesions were located in the frontal and temporal regions. Estimates of lesion volume based on MRI were frequently greater than with CT; however, MRI disclosed no additional lesions that required surgical evacuation. Neuropsychological assessment during the initial hospitalization revealed deficits in frontal lobe functioning and memory that were related to the size and localization of the lesions as defined by MRI. Follow-up MRI and neuropsychological testing at 1 month (13 cases) and 3 months (six cases) disclosed marked reduction of lesion size paralleled by improvement in cognition and memory. These findings encourage further investigation of the prognostic utility of MRI for the clinical management and rehabilitation of mild or moderate head injury.

Brain stem abscess managed with computed tomography-guided stereotactic aspiration

The importance of stereotactic aspiration to the successful management of three cases of brain stem abscess is discussed with special reference to the advantages offered over medical treatment alone. Stereotactic aspiration allows evacuation of pus, accurate bacteriological diagnosis, selection of an optimal antibiotic regimen, and instillation of antibiotics directly into the abscess cavity. In two of the three cases described here, the abscess reaccumulated after initial aspiration despite appropriate maximal medical therapy. A repeat aspiration was required before resolution occurred. We conclude that medical management alone is not adequate for some cases of brain stem abscess. There was no morbidity that could be attributed to the procedure, suggesting that the risk of stereotactic aspiration is probably quite low and is likely to be less than the risk of incorrect diagnosis, suboptimal choice of antibiotics, or progression of the lesion despite appropriate maximal medical therapy.

Advances in pediatric neurosurgery

Pediatric neurosurgery is benefiting greatly from technologic advances in medicine that are enabling earlier and more definitive diagnosis and treatment of a variety of conditions amenable to surgical correction. This article familiarizes the pediatrician with some of the many applications of the new technology as well as some newer concepts of disease management in pediatric neurosurgery.

Computed tomography in herpes simplex encephalitis

Nine patients with herpes simplex encephalitis examined by CT scan were reviewed. A total of 15 satisfactory scans was analyzed. The majority of our cases had CT scan abnormalities: lucency 63% (5 of 8, one case with suboptimal scan), mass effect 50% (4 of 8), abnormal contrast enhancement 57% (4 of 7). The earliest CT scan finding was lucency, presented in two out of three cases studied within 48 hours following onset of symptoms. The primary role of CT scan is to support the suspected diagnosis of herpes simplex encephalitis as well as to indicate the best site for brain biopsy and to permit early effective treatment with adenine arabinoside.