Treatment of critical bleeding events in patients with immune thrombocytopenia: a protocol for a systematic review and meta-analysis

BACKGROUND

Critical bleeding events in adults and children with ITP are medical emergencies; however, evidence-based treatment protocols are lacking. Due to the severe thrombocytopenia, (typically platelet count less than 20 × 109/L), a critical bleed portends a high risk of death or disability. We plan to perform a systematic review and meta-analysis of treatments for critical bleeding in patients with ITP that will inform evidence-based recommendations.

METHODS

Literature searches will be conducted in four electronic databases: Ovid MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and PubMed. Eligible studies will be randomized controlled trials or observational studies that enrolled patients with ITP describing one or more interventions for the management of critical bleeding. Title and abstract screening, full-text screening, data extraction, and risk of bias evaluation will be conducted independently and in duplicate using Covidence and Excel. Outcomes will be pooled for meta-analysis where appropriate or summarized descriptively. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology will be used to evaluate the certainty of the evidence. Primary outcomes of interest will include frequency of critical bleeds, mortality and bleeding-related mortality, bleeding resolution, platelet count, and disability.

DISCUSSION

Evidence-based treatments for critical bleeding in patients with ITP are needed to improve patient outcomes and standardize care in the emergency setting.

SYSTEMATIC REVIEW REGISTRATION

CRD42020161206.

Comparing the suitability of virtual versus in-person care: Perceptions from pediatricians

OBJECTIVES

The COVID-19 pandemic compelled a portion of healthcare to be delivered virtually. As the pandemic waned, health systems strived to find a balance between re-incorporating in-person care while maintaining virtual care. To find when virtual or in-person encounters are more appropriate, we surveyed pediatricians' perceptions when comparing the suitability of virtual care to in-person care.

METHODS

We surveyed a Canadian tertiary-level pediatric hospital where pediatricians assessed whether specific clinical encounters or tasks were more or less effective virtually than when performed in person. Pediatricians also rated the importance of clinical and patient factors when deciding if a patient needs to be seen in person.

RESULTS

Of 160 pediatrics faculty members, 56 (35%) responded to the survey. When assessing different types of clinical encounters, triage, multidisciplinary meetings, discharge, and follow ups were more likely to favor virtual encounters. However, first consultations and family meetings were more likely to favor in-person encounters. Regarding clinical tasks, pediatricians were more likely to endorse explaining test results, offering treatment recommendations, and obtaining patient histories virtually. On the contrary, there was a preference for physical examinations, assessing patients visually, and assessing developmental milestones to be performed in person. When deciding if a patient should be seen in person versus virtual, pediatricians rated the patient's condition and communication barriers as the most important factors favoring an in-person appointment.

DISCUSSION

These results offer an initial framework for pediatricians when choosing which encounter type may be most appropriate for their patients between virtual or in-person appointments.

Therapeutic Effects of Medicinal Cannabinoids on the Gastrointestinal System in Pediatric Patients: A Systematic Review

Changes in cannabis legalization have generated interest in medicinal cannabinoids for therapeutic uses, including those that target the gastrointestinal (GI) tract. These effects are mediated through interactions with the endocannabinoid system. Given the increasing societal awareness of the therapeutic potential of cannabinoids, it is important to ensure pediatric representation in clinical studies investigating cannabinoid use. This systematic review aims to assess the efficacy of medicinal cannabinoids in treating GI symptoms in pediatric patients. A literature search of Medline, Embase, CINAHL, Web of Science, and the Cochrane Library was performed from inception until June 23, 2020. Study design, patient characteristics, type, dose and duration of medicinal cannabinoid therapy, and GI outcomes were extracted. From 7303 records identified, 5 studies met all inclusion criteria. Included studies focused on chemotherapy-induced nausea, inflammatory bowel disease, and GI symptoms associated with severe complex motor disorders. Results varied based on the symptom being treated, the type of cannabinoid, and the patient population. Medicinal cannabinoids may have a potential role in treating specific GI symptoms in specific patient populations. The limited number and heterogenicity of included studies highlight the demand for future research to distinguish effects among different cannabinoid types and patient populations and to examine drug interactions. As interest increases, higher quality studies are needed to understand the efficacy of cannabinoids as a pediatric GI treatment and whether these benefits outweigh the associated risks (Registration Number: PROSPERO CRD42020202486).

Direct oral anticoagulants after bariatric surgery-What is the evidence?

BACKGROUND

Obesity is a global epidemic and bariatric surgery is used with increasing frequency to treat its complications. The extent to which bariatric surgery alters the efficacy, safety, and pharmacokinetics of direct oral anticoagulants (DOACs) is unknown.

AIMS

In this review, we summarize the evidence supporting the use of DOACs after bariatric surgery and apply our findings to resolve several clinical cases.

MATERIALS & METHODS

We systematically searched MEDLINE, EMBASE, Cochrane Library, CINAHL and ClinicalTrials.gov from January 1, 2000, to June 15, 2021 for randomized and non-randomized studies evaluating the use of DOACs for any indication after bariatric surgery. Two reviewers independently screened titles, abstracts, and full-text articles. Clinical and pharmacokinetic outcomes were pooled by random-effects meta-analysis with inverse variance weighting. We used the Newcastle-Ottawa scale to assess risk of bias in non-randomized studies and assessed the certainty of evidence with GRADE.

RESULTS

From 2519 records, we included 28 studies (n = 3229 patients): no randomized trials, 7 cohort studies, 6 case series, and 15 case reports. Incidence rates for arterial thromboembolism, venous thromboembolism and major bleeding were: 0.73 (95% confidence interval [CI]: 0.01-5.10), 2.45 (95% CI: 0.40-7.94), and 3.40 (95% CI: 0.80-9.36) events per 100 patient-years, respectively. The pooled proportion of peak direct oral anticoagulant drug levels within the expected range was 58% (95% CI: 39%-74%).

CONCLUSION

There appears be substantial risk of DOAC malabsorption after bariatric surgery that could affect clinical outcomes, however the certainty of evidence was very low.

PROSPERO

CRD42020202636.

Use of thrombolytic agents to treat neonatal thrombosis in clinical practice

Among children, neonates have the highest incidence of thrombosis. Thrombolytic agents are used for the management of life and/or organ-threatening thrombosis. Literature on the efficacy and safety of thrombolytic agents in neonates is limited. We reviewed the evidence on dosing, administration, monitoring and treatment duration of tissue plasminogen activator (tPA), streptokinase and urokinase (URK) in neonates (≤ 28days). A systematic literature search was conducted of current databases from inception until 31 March 2021. The initial search yielded 6881 articles and 18 were retained for review. tPA, streptokinase and URK was utilized in 12, seven and four studies on 115, 51 and 16 patients, respectively. The dose range for tPA, streptokinase and URK was 0.01 -0.6 mg/kg/h, 50-2000 and 1000-0 000 units/kg/h, respectively, and treatment duration ranged from 30 min to 30 days. This is the first study to objectively summarize the efficacy and safety of thrombolytic agents in neonates. Overall, thrombolysis was associated with 87.9% complete or partial thrombus resolution and 7.4% recurrence risk. The bleeding risk associated with thrombolytic agents was 23.1% on pooled analysis, which is higher than other anticoagulants. Larger prospective studies are required to determine effective dosing regimens of these therapeutic drugs and further clarify their efficacy and safety. Blood Coagul Fibrinolysis 33:000-000 Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.

A241 KIWIFRUIT AND KIWIFRUIT EXTRACTS FOR TREATMENT OF CONSTIPATION: A SYSTEMATIC REVIEW AND META-ANALYSIS

Aims

This systematic review and meta-analysis aimed to determine the effectiveness of kiwifruit or kiwifruit extracts in thetreatment of constipation.

Methods

Electronic databases were searched from inception until January 2021. Eligible studies enrolled participants with functional constipation (FC) or irritable bowel syndrome with constipation (IBS-C) with randomization to receive kiwifruit or kiwifruit extracts vs. any non-kiwifruit control. Standardized meandifference (SMD) or mean difference (MD) with confidence intervals (CI) were determined for the following outcomes: weekly frequency of spontaneous bowel movements (SBM) and Bristol Stool Scale (BSS). GRADE approach was used to rate the certainty of evidence. PROSPERO registration number CRD42020207365.

Results

Seven randomized controlled trials including 399 participants (82% female; mean age 42 years [Standard Deviation 14.6]) were included. Compared with placebo, kiwifruit extract might increase weekly frequency of SBM (MD 1.36; 95% CI -0.44 to 3.16) with low certainty evidence. Kiwifruit had an uncertain effecton BSS (SMD 1.54; 95% CI -1.33 to 4.41) with very low certainty evidence. Compared with psyllium, kiwifruitmay increase weekly SBM (MD 1.1; 95% CI -0.02 to 2.04) and may increase BSS (softer stools) (MD 0.63;95% CI 0.01 to 1.25) both with low certainty evidence. Compared to placebo, kiwifruit encapsulated extracts may result in an increase in minor adverse events (Relative Risk 4.58; 95% CI 0.79 to 26.4).

Conclusions

Among individuals with constipation, overall low certainty of evidence indicate that kiwifruit may increase SBM when compared to placebo or psyllium. Although overall results are promising, establishing therole of kiwifruit in FC or IBS-C requires large, methodologically rigorous trials.

Funding Agencies

None

A246 GASTROINTESTINAL ADVERSE EVENTS OF CANNABINOIDS IN PEDIATRIC POPULATIONS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background

Use of therapeutic cannabinoids in the pediatric population has increased in recent years within areas of epilepsy, palliative care, and cancer. Given the endocannabinoid system plays a crucial role in gastrointestinal (GI) homeostasis, exogenous cannabinoids have the potential to develop GI related side effects. While some GI adverse events have been reported with the use of therapeutic cannabinoids, the full profile of GI adverse events in the pediatric population is still unknown.

Aims

To understand the impact of therapeutic cannabinoids on the GI system of pediatric patients, we performed a systematic review and meta-analysis to assess the prevalence of various GI-related adverse events arising from cannabinoid usage within pediatric populations.

Methods

Searches were conducted from OVID MEDLINE, EMBASE, CINAHL, Web of Science, and The Cochrane Library for study screening. The included studies were quantitatively assessed for GI adverse events including nausea, diarrhea, increased appetite, decreased appetite, weight gain, weight loss, constipation, abdominal pain, and unspecified events. The prevalence along with their relation towards diagnosis, type of cannabinoid, dosage, duration of treatment, and study type were also assessed.

Results

Among a total of 1201 patients across 25 included studies, an overall prevalence of 33.91% GI adverse events was observed in patients. The statistical analysis of the pediatric population displayed no relation between therapeutic cannabinoid usage and GI adverse events, bearing a large heterogeneity (I² = 91%, P < 0.01). Upon analysis based on study type, a significant difference was observed between prospective and retrospective studies in categories of all GI adverse events, diarrhea, and decreased appetite, with prospective studies displaying a higher prevalence in all three categories. Nausea symptoms showed a significant negative correlation with maximum dosage of cannabinoid used. In addition, diarrhea was found to have a higher prevalence in Dravet syndrome related to an ion channel gene mutation (SCN1A) compared to other epilepsy patients.

Conclusions

While the meta-analysis did not identify any significant associations between therapeutic cannabinoid usage and GI adverse events, there remains the potential for interactions of cannabinoids on GI symptoms depending on dosage and underlying patient factors.

Funding Agencies

Farncombe Family Digestive Health Research Institute

A68 THERAPEUTIC EFFECTS OF MEDICINAL CANNABINOIDS ON THE GASTROINTESTINAL SYSTEM IN PEDIATRIC PATIENTS: A SYSTEMATIC REVIEW

Background

Changes in cannabis legalization in recent years have led to an increasing interest in medicinal cannabinoids for a variety of therapeutic uses, including those which target the gastrointestinal tract. These effects are mediated by interactions with the endocannabinoid system. As this system is present in early life, it is important to ensure pediatric representation in clinical studies regarding cannabinoid use.

Aims

We conducted a systematic review to assess the efficacy of medicinal cannabinoids in treating gastrointestinal symptoms in pediatric patients.

Methods

A literature search of Medline, Embase, CINAHL, Web of Science and the Cochrane Library was conducted from inception. Study design, patient characteristics, type, dose and duration of medicinal cannabinoid therapy, and gastrointestinal outcomes were extracted.

Results

From 7,303 records identified, five studies met all inclusion criteria. The focus of the included studies ranged from chemotherapy-induced nausea, inflammatory bowel disease and gastrointestinal symptoms associated with severe complex motor disorders. Results varied based on the symptom being treated, the type of cannabinoid, and the patient population, however, the most consistently improved symptom was chemotherapy-induced nausea.

Conclusions

Medicinal cannabinoids may have a potential role in treating specific gastrointestinal symptoms in specific patient populations. The limited number and heterogenicity of included studies highlight the requirement for future research to distinguish the effects amongst different cannabinoid types, patient populations and examine drug-interactions. In addition, the molecular interplay between disease processes, the endocannabinoid system and medicinal cannabinoids require investigation to further understand the mechanisms behind this intervention.

Funding Agencies

Natural Sciences and Engineering Research Council of Canada; Farncombe Family Digestive Health Research Institute

Global Temporal Patterns of Age Group and Sex Distributions of COVID-19

Since the beginning of 2020, COVID-19 has been the biggest public health crisis in the world. To help develop appropriate public health measures and deploy corresponding resources, many governments have been actively tracking COVID-19 in real time within their jurisdictions. However, one of the key unresolved issues is whether COVID-19 was distributed differently among different age groups and between the two sexes in the ongoing pandemic. The objectives of this study were to use publicly available data to investigate the relative distributions of COVID-19 cases, hospitalizations, and deaths among age groups and between the sexes throughout 2020; and to analyze temporal changes in the relative frequencies of COVID-19 for each age group and each sex. Fifteen countries reported age group and/or sex data of patients with COVID-19. Our analyses revealed that different age groups and sexes were distributed differently in COVID-19 cases, hospitalizations, and deaths. However, there were differences among countries in both their age group and sex distributions. Though there was no consistent temporal change across all countries for any age group or either sex in COVID-19 cases, hospitalizations, and deaths, several countries showed statistically significant patterns. We discuss the potential mechanisms for these observations, the limitations of this study, and the implications of our results on the management of this ongoing pandemic.

Impaired motility in Barrett's esophagus: A study using high-resolution manometry with physiologic challenge

BACKGROUND

Esophageal dysmotility may predispose to Barrett's esophagus (BE). We hypothesized that high-resolution manometry (HRM) performed with additional physiologic challenge would better delineate dysmotility in BE.

METHODS

Included patients had typical reflux symptoms and underwent endoscopy, HRM with single water swallows and adjunctive testing with solids and rapid drink challenge (RDC) before ambulatory pH-impedance monitoring. BE and endoscopy-negative reflux disease (ENRD) subjects were compared against functional heartburn patient-controls (FHC). Primary outcome was incidence of HRM contractile abnormalities with standard and adjunctive swallows. Secondary outcomes included clearance measures and symptom association on pH-impedance.

KEY RESULTS

Seventy-eight patients (BE 25, ENRD 27, FHC 26) were included. Water swallow contractility was reduced in both BE (median DCI 87 mm Hg/cm/s) and ENRD (442 mm Hg/cm/s) compared to FHC (602 mm Hg/cm/s; P < .001 and .04, respectively). With the challenge of solid swallows and RDC, these parameters improved in ENRD (solids = 1732 mm Hg/cm/s), becoming similar to FHC (1242 mm Hg/cm/s; P = .93), whereas abnormalities persisted in BE (818 mm Hg/cm/s; P < .01 c.f. FHC). In BE and ENRD, reflux events (67 vs 57 events/24 hour) and symptom frequency were similar; yet symptom correlation was significantly better in ENRD compared to BE, which was comparable to FHC (symptom index 30% vs 4% vs 0%, respectively). Furthermore, bolus clearance and exposure times were more pronounced in BE (P < .01).

CONCLUSIONS & INFERENCES

Reduced contractile effectiveness persisted in BE with the more representative esophageal challenge of swallowing solids and free drinking; while in ENRD and FHC peristalsis usually improved, demonstrating peristaltic reserve. Furthermore, symptom association and refluxate clearance were reduced in BE. These factors may underlie BE pathogenesis.

Early Probiotic Supplementation for Eczema and Asthma Prevention: A Randomized Controlled Trial

OBJECTIVES

To determine if probiotic administration during the first 6 months of life decreases childhood asthma and eczema.

METHODS

We conducted a randomized, double-blind controlled trial of Lactobacillus rhamnosus GG (LGG) supplementation on the cumulative incidence of eczema (primary end point) and asthma and rhinitis (secondary end points) in high-risk infants. For the first 6 months of life, intervention infants (n = 92) received a daily dose of 10 billion colony-forming units of LGG and 225 mg of inulin (Amerifit Brands, Cromwell, CT), and control infants (n = 92) received 325 mg of inulin alone. We used survival analysis methods to estimate disease incidences in the presence or absence of LGG and to estimate the efficacy of LGG in delaying or preventing these diseases.

RESULTS

Infants were accrued over a 6-year period (median follow-up: 4.6 years; 95% retention rate at 2 years). At 2 years of age, the estimated cumulative incidence of eczema was 30.9% (95% confidence interval [CI], 21.4%-40.4%) in the control arm and 28.7% (95% CI, 19.4%-38.0%) in the LGG arm, for a hazard ratio of 0.95 (95% CI, 0.59-1.53) (log-rank P = .83). At 5 years of age, the cumulative incidence of asthma was 17.4% (95% CI, 7.6%-27.1%) in the control arm and 9.7% (95% CI, 2.7%-16.6%) in the LGG arm, for a hazard ratio of 0.88 (95% CI, 0.41-1.87) (log-rank P = .25).

CONCLUSIONS

For high-risk infants, early LGG supplementation for the first 6 months of life does not appear to prevent the development of eczema or asthma at 2 years of age.

Effect of Helicobacter pylori eradication on treatment of gastro-oesophageal reflux disease: a double blind, placebo controlled, randomised trial

BACKGROUND

The role of Helicobacter pylori eradication in the management of gastro-oesophageal reflux disease (GORD) is controversial. We hypothesised that H pylori eradication leads to worsened control of reflux disease.

METHODS

Consecutive patients with weekly reflux symptoms were prospectively recruited for endoscopy and symptom evaluation. Patients were enrolled if they had H pylori infection and required long term acid suppressants. Eligible patients were randomly assigned to omeprazole triple therapy (HpE group) or omeprazole with placebo antibiotics (Hp+ group) for one week. Omeprazole 20 mg daily was given for eight weeks for healing of oesophagitis and symptom relief. This was followed by a maintenance dose of 10 mg daily for up to 12 months. The primary study end point was the probability of treatment failure within 12 months, which was defined as either incomplete resolution of symptoms or oesophagitis at the initial treatment phase, or relapse of symptoms and oesophagitis during the maintenance phase. Predictors of treatment failure were determined by Cox's proportional hazards model.

RESULTS

A total of 236 GORD patients were screened and 113 (47.9%) were positive for H pylori; 104 (92%) patients were included in the intention to treat analysis (53 in the HpE group and 51 in the Hp+ group). Thirty one patients (30%) had erosive oesophagitis at baseline. H pylori was eradicated in 98% of the HpE group and in 3.9% of the Hp+ group. Overall, 15 patients (28.3%) in the HpE group and eight patients (15.7%) in the Hp+ group had treatment failure. The 12 month probability of treatment failure was 43.2% (95% confidence interval (CI) 29.9-56.5%) in the HpE group and 21.1% (95% CI 9.9-32.3%) in the Hp+ group (log rank test, p = 0.043). In the Cox proportional hazards model, after adjustment for the covariates age, sex, erosive oesophagitis, hiatus hernia, degree of gastritis, and severity of symptoms at baseline, H pylori eradication was the only predictor of treatment failure (adjusted hazard ratio 2.47 (95% CI 1.05-5.85)).

CONCLUSION

H pylori eradication leads to more resilient GORD.

Epulis granulomatosa: extraction sequellae

Epulis granulomatosa is a post-surgical lesion emanating from an extraction socket. It can be misdiagnosed with lesions of similar appearance, for example, foreign body or pyogenic granulomas, or as a herniation of the maxillary sinus. Based on clinical appearance and microscopic description, granulomas all appear to represent essentially the same lesion. However, pathonomonically, the epulis granulomatosa emanates only from an extraction socket; the other granulomas can be found anywhere in the body.

A model for signal transmission in an ear having hair cells with free-standing stereocilia. II. Macromechanical stage

A model of the signal-processing properties of the macromechanical system of the alligator-lizard middle and inner ear is developed. The model is based on measurements (as a function of tone frequency) of ossicular and basilar-membrane motion and of acoustic input-admittance at the tympanic membrane before and after alterations of middle-ear and inner-ear structures. From the structure of the ear, we formulate an equivalent electric network consisting of six admittance blocks and two transformers. The admittance blocks represent the mechanical properties of particular structures, e.g. the tympanic membrane (TM), the ossicle, the TM-ossicular joint, the vestibule, the basilar membrane and the helicotrema. The transformers represent the conversions from acoustical to mechanical variables performed by the TM-ossicular system and by the columella footplate. The block admittances and transformer ratios are inferred from the measurements, and each admittance is approximated by a network with a few simple elements. The resulting model fits the experimental results satisfactorily, allows correlations between specific structures and response behavior, and predicts the macromechanical transfer function. This transfer function acts as the first stage of a model of the alligator-lizard auditory periphery (Weiss et al., Weiss and Leong, 1985, Hearing Res. 20, 131-138, 157-174, 175-195). In the model the frequency dependence of basilar-membrane motion (1) is determined primarily by the tympanic membrane and extracolumella in the middle frequencies and (2) is affected by the helicotrema at low frequencies and the TM-ossicular joint at high frequencies.

A model for signal transmission in an ear having hair cells with free-standing stereocilia. IV. Mechanoelectric transduction stage

A model is described for mechanoelectric transduction in hair cells with free-standing stereocilia in the alligator lizard cochlea. The model relates the angular displacement of the stereocilia to the receptor potential in the absence of the hair cell's membrane capacitance whose effect is considered elsewhere (Leong and Weiss, 1985, in preparation). The model consists of two parts: a population of membrane ionic channels and an electric network that relates the channel conductance to the equivalent resistance of the hair cell. The membrane ionic channels tend to open when the stereociliary tuft is displaced toward the kinocilium (or basal body) and tend to close when the tuft is oppositely displaced. The fraction of channels that is open for a given tuft displacement is governed by Boltzmann statistics and the energies of open and closed configurations of the channels are separated by a single energy barrier whose height depends on the angular displacement of the stereociliary tuft. The resulting channel conductance is a hyperbolic-tangent type function of the angular displacement of the stereociliary tuft. The channel conductance is coupled to the rest of the hair cell by an equivalent electric network containing constant resistance and a capacitance. The Thévenin equivalent resistance change across the basolateral membrane of the hair cell, called the transducer function, is also a hyperbolic-tangent type function of angular displacement. The parameters of the channel conductance and the values of resistances in the hair-cell electric model determine the scale factors and the location of the operating point of this hyperbolic-tangent type function. The hyperbolic-tangent type function is a specific example of a class of monotonically decreasing and saturating, or sigmoidal, transducer functions. The spectral properties of sigmoidal transducer functions are examined for sinusoidal angular displacements of amplitude theta. General results are obtained for arbitrary sigmoidal transducer functions; particular results are obtained for the hyperbolic-tangent type function. General conclusions concerning spectral components of the resistance change include: all spectral components are independent of the frequency of the angular displacement; the constant or DC component can be positive or negative; the fundamental component is 180 degrees out of phase with the angular displacement, i.e. the resistance decreases when the stereocilia are displaced towards the kinocilium; for small values of theta, the magnitude of the nth harmonic tends to grow as theta n for n greater than 0; the zeroth harmonic or DC component grows as theta 2.(ABSTRACT TRUNCATED AT 400 WORDS)

A model for signal transmission in an ear having hair cells with free-standing stereocilia. III. Micromechanical stage

Measurements have shown that the sound-induced motion of free-standing stereocilia of hair cells in the alligator lizard cochlea exhibits tonotopically organized frequency selectivity that is correlated with the geometry of the stereociliary tuft. We propose a model in which basilar-membrane motion causes vibration of the receptor organ which drags the stereocilia back and forth through the endolymph. The stereociliary tuft is represented as a rigid rod attached to the cuticular plate by a compliant hinge. Viscous and inertial forces exerted by the endolymph on the rod are computed approximately. A transfer function, H mu(f), is derived that relates rod angular displacement to basilar-membrane velocity. H mu(f) has low- and high-frequency slopes of 10 and -20 dB/decade, respectively. The resonant frequency of H mu(f) depends on the dimensions of the rod because this frequency is inversely proportional to the square root of the product of the moment of inertia of the rod, which depends on rod dimensions, and the compliance of the hinge, which does not. In most respects, measurements of frequency selectivity and tonotopic organization of hair cells and cochlear neurons in the alligator lizard, can be accounted for by an input transfer function, HI(f) = Hm(f)H mu(f)Ha(f), where Hm(f) is the macromechanical transfer function that relates sound pressure at the tympanic membrane to basilar-membrane velocity (Rosowski et al., 1985, Hearing Res. 20, 139-155), and Ha(f) is a first-order lowpass filter. Mechanisms that could produce the additional lowpass filter process are discussed.