Modeling of Ultrasound Stimulation of Adolescent Pancreas for Insulin Release Therapy

OBJECTIVES

Our previous published studies have focused on safety and effectiveness of using therapeutic ultrasound (TUS) for treatment of type 2 diabetes mellitus (T2DM) in preclinical models. Here we present a set of simulation studies to explore potential ultrasound application schemes that would be feasible in a clinical setting.

METHODS

Using the multiphysics modeling tool OnScale, we created two-dimensional (2D) models of the human abdomen from CT images captured from one normal weight adolescent patient, and one obese adolescent patient. Based on our previous studies, the frequency of our TUS was 1 MHz delivered from a planar unfocused transducer. We tested five different insonation angles, as well as four ultrasound intensities combined with four different duty factors and five durations of application to explore how these variables effect the peak pressure and temperature delivered to the pancreas as well as surrounding tissue in the model.

RESULTS

We determined that ultrasound applied directly from the anterior of the patient abdomen at 5 W/cm² delivered consistent acoustic pressures to the pancreas at the levels which we have previously found to be effective at inducing an insulin release from preclinical models.

CONCLUSIONS

Our modeling work indicates that it may be feasible to non-invasively apply TUS in clinical treatment of T2DM.

Sensorineural Hearing Loss and Tinnitus Characteristics in Patients With Idiopathic Intracranial Hypertension

OBJECTIVES

To characterize patterns of sensorineural hearing loss (SNHL) and tinnitus in patients with idiopathic intracranial hypertension (IIH).

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary referral center.

PATIENTS

Adult patients diagnosed with IIH via lumbar puncture (LP) between 2010 and 2020 who had available audiograms. The study included a total of 40 patients; 33 women, and 7 men with a median age of 43.

INTERVENTIONS

Diagnostic LP and audiogram.

MAIN OUTCOME MEASURES

Otologic symptoms, ophthalmologic signs, hearing thresholds, cerebrospinal fluid opening pressures.

RESULTS

The most commonly reported symptoms were tinnitus in 28 (70%, 23 pulsatile and 5 tonal), aural fullness in 11 (28%), and vertigo in 10 (25%). Twenty-nine patients had ophthalmologic examinations and 18 had evidence of papilledema. Twenty-five (63%) patients had hearing loss in at least one ear at one frequency range. Patients presented with both unilateral and bilateral hearing loss across low, middle, and high frequency ranges. No significant association was observed between hearing loss threshold and LP opening pressure except for 250 Hz in the left ear. After stratification by tinnitus group (pulsatile, tonal, and no tinnitus), no significant difference was found between mean hearing loss threshold at different frequencies. In addition, no significant mean age difference was identified in patients within each tinnitus group.

CONCLUSIONS

There was no classic pattern or presentation for hearing loss in our IIH patients. They developed sudden, unilateral, or bilateral SNHL in low, middle, or high frequency range. The degree of hearing loss did not correlate with CSF opening pressure.

Characterization of Sensorineural Hearing Loss in Adult Patients With Sickle Cell Disease: A Systematic Review and Meta-analysis

OBJECTIVES AND MAIN OUTCOME MEASURES

To determine the prevalence of sensorineural hearing loss (SNHL) attributable to sickle cell disease (SCD) in the global adult population and to identify factors contributing to its severity.

STUDY DESIGN

Systematic Review and Meta-analysis.

METHODS

We performed a comprehensive literature search for scientific articles in PubMed, Scopus, CINAHL, Web of Science, and the Cochrane Library that reported the incidence of hearing loss in populations over 18 years of age with SCD.

RESULTS

We identified 138 studies from the initial search, 12 of which met inclusion criteria and were utilized for data analysis. A total of 636 SCD patients and 360 controls were included in the Cochrane Review Manager 5.3 meta-analysis. There was a statistically significant increase in the prevalence of SNHL in adults with SCD compared with the general population with a cumulative risk ratio (RR) of 6.03.

CONCLUSIONS

This is the first systematic investigation of the relationship between SCD and SNHL in adult patients across the globe. SNHL is more prevalent in patients with SCD, specifically those of the HbSS genotype, than the general population likely due to the pathophysiology of the disease and its effects on labyrinthine microvasculature. The increased prevalence of SNHL in the adult SCD population warrants future research into the predictors of SNHL severity and merits routine audiometric monitoring of adult SCD patients.

Prevalence of Sensorineural Hearing Loss in Pediatric Patients with Sickle Cell Disease: A Meta-analysis

OBJECTIVES

To determine the prevalence of Sensorineural Hearing Loss (SNHL) attributable to Sickle Cell Disease (SCD) in the global pediatric population and to identify factors contributing to its severity.

STUDY DESIGN

Meta-analysis.

METHODS

We performed a comprehensive literature search for scientific articles in PubMed, Scopus, CINAHL, Web of Science, and the Cochrane Library that reported the incidence of hearing loss in populations under 18 years of age with excluding studies analyzing patients on iron chelation therapy, adults, or those without objective audiological analysis.

RESULTS

We identified 138 initial studies with 17 selected for analysis after applying the exclusion criteria. A total of 1,282 SCD patients and 553 controls were included in the meta-analysis. There was a statistically significant increase in the prevalence of SNHL in children with SCD compared to the general population with a cumulative risk ratio of 3.33.

CONCLUSION

This is the first systematic investigation of the relationship between SCD and SNHL in pediatric patients across the globe. The increased prevalence of SNHL in the pediatric SCD population warrants future research into the predictors of SNHL severity and merits routine audiometric monitoring of SCD patients to reduce the social and developmental morbidity of hearing loss at a young age. PROSPERO Registration #: CRD42019132601. Laryngoscope, 131:1147-1156, 2021.

Absence of Axoglial Paranodal Junctions in a Child With CNTNAP1 Mutations, Hypomyelination, and Arthrogryposis

Leukodystrophies and genetic leukoencephalopathies are a heterogeneous group of heritable disorders that affect the glial-axonal unit. As more patients with unsolved leukodystrophies and genetic leukoencephalopathies undergo next generation sequencing, causative mutations in genes leading to central hypomyelination are being identified. Two such individuals presented with arthrogryposis multiplex congenita, congenital hypomyelinating neuropathy, and central hypomyelination with early respiratory failure. Whole exome sequencing identified biallelic mutations in the CNTNAP1 gene: homozygous c.1163G>C (p.Arg388Pro) and compound heterozygous c.967T>C (p.Cys323Arg) and c.319C>T (p.Arg107*). Sural nerve and quadriceps muscle biopsies demonstrated progressive, severe onion bulb and axonal pathology. By ultrastructural evaluation, septate axoglial paranodal junctions were absent from nodes of Ranvier. Serial brain magnetic resonance images revealed hypomyelination, progressive atrophy, and reduced diffusion in the globus pallidus in both patients. These 2 families illustrate severe progressive peripheral demyelinating neuropathy due to the absence of septate paranodal junctions and central hypomyelination with neurodegeneration in CNTNAP1-associated arthrogryposis multiplex congenita.