Incidence of long COVID and associated psychosocial characteristics in a large U.S. city

PURPOSE

Persistent residual effects from Coronavirus Disease-2019 (COVID-19) have been observed with varying definitions of "Long COVID" and little comprehensive examination. This study examined the incidence and psychosocial correlates of Long COVID using different definitions.

METHODS

Data were analyzed from a citywide sample of 3595 adults with lab-confirmed cases of COVID-19 that were surveyed over 3 months. Rates of Long COVID were examined in terms of Post-Acute COVID (PAC), defined as at least one symptom lasting for 4 weeks, and three levels of Post-COVID Syndrome (PCS) that included experiencing at least one symptom for 3 months (PCS-1), experiencing three or more symptoms for 3 months (PCS-2), or experiencing at least one of the same symptoms for 3 months (PCS-3).

RESULTS

Among the 686 participants who completed baseline, 1-month, and 3-month follow-up assessments, 75.7% had PAC, 55.0% had PSC-1, 26.5% had PSC-2, and 19.0% had PSC-3. Comparing participants with PAC and PSC-3 in the total sample with inverse probability weighting, multivariable analyses revealed being female, Asian or Native American, greater reported longlines, and less social support were predictive of PCS-3.

CONCLUSION

Residual effects of COVID-19 are very common and nearly one-fifth of our sample met the most restrictive definition of Long COVID warranting concern as a public health issue. Some demographic and social factors may predispose some adults to Long COVID, which should be considered for prevention and population health.

Incidence and psychiatric predictors of Long COVID beyond 3 months in a city-wide community sample in Texas

BACKGROUND

Studies have emerged about a syndrome of persistent symptoms of Coronavirus Disease-2019 (COVID-19) infection called 'Long COVID', which have mostly focused on the first 3 months. This study examined rates and predictors of Long COVID symptoms lasting beyond 3 months (termed Long2 COVID).

METHODS

A longitudinal cohort study using a population-based sample of 511 adults in San Antonio, Texas with laboratory-confirmed cases of COVID-19 were assessed for Long2 COVID. Inverse probability weighting was used.

RESULTS

In the sample, 19.18-59.10% met criteria for Long2 COVID depending on the definition. In general, Long COVID symptoms decreased after 3 months with the notable exception of an observed increase in loss of taste and smell. White Hispanic (adjusted odds ratio (aOR) = 7.66; 95% confidence interval (CI) = 1.78, 32.87) background and baseline depression symptoms (aOR = 1.30; 95% CI = 1.03, 1.65) were predictive of Long2 COVID. Long2 COVID was also associated with greater anxiety symptoms 6 months after onset of COVID-19.

CONCLUSIONS

A sizable proportion report COVID-19 symptoms lasting more than 3 months and some symptoms even increased over time. Adults who are Hispanic white adults or have depression may be at greater risk for Long2 COVID. Further research is needed on why some adults experience Long COVID and how to reduce the duration of illness.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

City-wide study of laboratory-confirmed COVID-19 cases in San Antonio: An investigation of stressful events accompanying infection and their relation to psychosocial functioning

Little is known about how Coronavirus Disease-2019 (COVID-19) infection is associated with stressful events (SEs) and stress-related psychological symptoms. This study examined the prevalence of SEs and incidence of stress-related symptoms accompanying COVID-19 infection. The association between these stress-related symptoms and psychosocial functioning were also examined. A city-wide sample of 3,595 adults with lab-informed cases of COVID-19 infection in San Antonio, Texas completed an online assessment of their psychological health and well-being after completing contact tracing activities in 2021-2022. A total 88.3% of participants reported exposure to SEs related to COVID-19 infection and their "worst" SEs were related to physical symptoms, fear of infecting others, financial problems, being isolated/quarantined, and loss of a loved one. Based on these SEs, 14.8% of the sample screened positive for substantial stress-related psychological problems related to COVID-19 infection. These psychological symptoms were strongly associated with worse psychosocial functioning. Together, these findings suggest SEs were commonly experienced by adults infected with COVID-19. Only a relatively small proportion reported substantial psychological symptoms related to their infection, but those who did had a high likelihood of impaired psychosocial functioning. Targeted support for individuals at high-risk of psychological symptoms following COVID-19 infection may help mitigate long-term psychological effects.

P1000Aetiology and efficacy of atrial fibrillation ablation in young adults

Introduction

Little is known regarding the aetiology or outcome of atrial fibrillation (AF) occurring in young adults. This retrospective analysis was performed to explore the demographics and efficacy of AF ablation in this population.

Methods

Patients were included who had undergone ≥1 AF ablation under the age of 40 between 2006-2018. Recurrence was defined as return of either documented AF or previous symptoms for &gt;30s following a 3-month blanking period. Initial exploratory co-variates were included in a univariate analysis and those terms with P-value of &lt;0.1 were then used to generate a Cox proportional-hazards multivariate model.

Results

124 patients (33.6 ± 4.7 yrs, 77% men), initially presenting with paroxysmal AF (pAF; n = 97) or persistent AF (n = 27), underwent 175 AF ablation procedures. 22.6% (n = 28) also had atrial flutter. Time from symptom onset to first ablation was 50.7 ± 46.2 months. Relevant cardiovascular-related demographics were analysed: hypertension in 8.9% (n = 11); diabetes in 1.6% (n = 2); positive family history of AF in 12.9% (n = 16); and family history of sudden cardiac death in 2.4% (n = 3). Mean CHA2DS2-VASc score was 0.35. Of those patients with documented echocardiogram imaging (n = 91), 26.4% (n = 24) had LA dilatation and 6.6% (n = 6) had LV dysfunction. Patients with LA dilatation underwent more ablations (2.3 ± 0.3) compared to controls (1.5 ± 0.1; p &lt; 0.001).

Ablation strategy was pulmonary vein isolation (PVI) only in 67.2% (n = 119), with additional ablation in the remaining: roof line in 18.9% (n = 33); cavotricuspid isthmus line in 13.1% (n = 23); mitral isthmus line in 2.3% (n = 4); superior vena cava isolation in 2.3% (n = 4); complex fractionated atrial electrograms in 14.9% (n = 26). Mean procedure time was 155 ± 41 min, mean ablation time was 1657 ± 991 s and mean fluoroscopy time was 32.6 ± 23.4 min. General anaesthesia was used in 43.4% (n = 76). Complications included femoral haematoma (n = 2), tamponade (n = 1) and pulmonary vein stenosis (n = 2).

90 days of follow-up was available for 137 procedures performed for pAF (n = 105) and persistent AF (n = 32). For pAF, overall recurrence was 61.9% for first ablations and 62.9% overall. Recurrence was 56.3% for persistent AF.

Factors significantly associated with increased AF recurrence in univariate analysis were

male gender (hazard ratio (HR) 2.3, 95% confidence interval (CI): 1.2-4.4, p = 0.011), hypertension (HR 0.5, CI: 0.2-1.1, p = 0.067), family history of sudden cardiac death (HR 6.8, CI: 1.6-29.0 , p = 0.010) and enlarged LA size (HR 2.2, CI: 1.3-3.6, p = 0.003). In multivariate analysis, the only significant predictor of poor outcome was enlarged LA size (HR 2.0, 95% CI: 1.2-3.5, p = 0.011).

Conclusions

Young patients with AF may have structurally abnormal hearts, and therefore do not only present with lone AF. LA size may be used as a predictor for success. Surveillance imaging may be useful to detect future structural change, which will be the subject of future prospective studies.

Abstract Figure. AF ablation recurrence in young adults

P1381Improved outcome in ablation of ventricular tachycardia in patients with structural heart disease under general anaesthetic

Background

Catheter ablation is an important adjunct to device implantation for secondary prevention of ventricular tachycardia (VT). However, several factors may influence the success of ablations in terms of long-term freedom from VT recurrence. A thus far little examined factor is the use of general anaesthetic (GA) versus conscious sedation during the procedure, which has been shown to improve outcomes in persistent atrial fibrillation (AF) ablation.

Methods

Patients with structural heart disease VT undergoing ablations from January 2015 to March 2019 were retrospectively followed up at a single centre. End points were recurrent VT or device therapy (shock or anti-tachycardia pacing) at one year. Hazard ratios (HR) were generated using a multivariate Cox-regression proportional hazards model including variables of age at ablation, sex, amiodarone use at time of ablation, scar age, left ventricular ejection fraction, use of GA, and diagnosis of: diabetes mellitus (DM), hypertension (HTN), renal impairment or AF.

Results

79 patients (74 male, mean age 68.2+/- 10.3 years) were included. A substrate-based strategy of late potential ablation was employed. 69 had ischaemic and 10 had non-ischaemic cardiomyopathy. Mean scar age was 13.8 +/- 9.8 years; EF was 40-50% in 27 patients, 30-40% in 26 and &lt; 30% in 26. 37 patients had implantable cardioverter defibrillators and 30 had cardiac resynchronisation therapy (CRT) defibrillator devices, 1 had a CRT- pacemaker device and 4 had dual chamber pacemakers. Comorbidities were: DM (16), HTN (31), renal impairment (13), AF (31). 62 patients (79.5%) were on amiodarone at the time of ablation. Mean procedure duration was 234.8 +/- 44.5 min and mean radiofrequency energy application time was 2247 +/- 862 s. 61 were first procedures and 18 were repeat procedures. One patient suffered a complication of groin haematoma. 62 patients (78.5%) underwent VT ablation under GA and 17 (21.5%) under sedation of midazolam and fentanyl. Patient characteristics did not differ between groups. Significant factors which increased freedom from VT recurrence or device therapy were HTN (88.9% vs 59.4%, HR 0.72, 95% confidence interval (CI): 0.007-0.75, p= 0.028), amiodarone treatment (50.0% vs 76.3%, HR 0.036, 95% CI: 0.003-0.404, p = 0.036) and ablation under GA rather than sedation (50.0% vs 75.0%, HR 0.055, 95% CI: 0.006-0.495, p = 0.01) (Fig 1).

Conclusions

In patients with structural heart disease undergoing VT ablation, outcomes are improved with the use of GA over conscious sedation.

Abstract Figure 1

P1451Catheter ablation in adults with Wolff-Parkinson-White syndrome: a "real-life" experience

Introduction. Radiofrequency catheter ablation (RFA) is 1st line treatment in symptomatic adult patients with Wolff-Parkinson-White syndrome (WPW). Patients with WPW are often quoted a high success rate for RFA but does this reflect reality? There is a paucity of recent literature and ongoing service developments in the UK may have a negative impact on success by reducing individual operator experience of adult WPW cases (i.e. increasing numbers of cardiac electrophysiologists in each department, patients more likely to undergo RFA as children). In contrast, technological developments (e.g. 3D mapping, steerable sheaths) may have a positive impact on success of RFA in WPW.

Methods. We collected data on all patients with WPW scheduled for 1st time ablation between Jan 2006 and Dec 2018. All patients undergoing re-do RFA during this time were excluded. For comparison, we divided this timeframe into three periods: 2006-9, 2010-13 and 2014-18.

Results. The number of patients scheduled for RFA and the outcome is listed in the Table. The overall success rate was 86.5% and this figure remained constant throughout the 13 year time-frame. Significant complications occurred in 1.17% of cases. 19.9% of patients scheduled for an ablation had no ablation attempted for various reasons (‘safe’ pathway, proximity to AV node etc).

Conclusion. In our centre, the number of adult cases of WPW scheduled for RFA year-on-year remains constant. The complication rate is in line with published literature. The RFA success rate is lower than the published data. As expected, success rate of RFA for WPW varies according to accessory pathway location. 1 in 5 cases scheduled for ablation did not proceed to ablation. This highlights an area where more effective resource planning from the outset can be undertaken.

Table 2006-9 2010-13 2014-18 Patients scheduled for RFA, n 181 152 179 Patients who underwent RFA, n 162 121 127 Overall RFA success rate, % (n) 85.6 (160) 86.6 (119) 87.4 (127) Success rate by AP location, % (n) Free wall Left 91.5 (71) 91.8 (49) 95.3 (64) Right 76.9 (13) 77.8 (9) 60.0 (5) Septal Anterior 77.8 (9) 88.9 (9) 100.0 (4) Mid 75.0 (8) 90.0 (10) 66.7 (3) Posterior 86.0 (57) 82.9 (41) 79.6 (49) RFA success rate in patients with Wolff-Parkinson-White syndrome. AP = accessory pathway, RFA = radiofrequency catheter ablation

A Prospective Study of Spectrum, Risk Factors and Immediate Outcome of Congenital Anomalies in Bida, North Central Nigeria

Background:

Congenital disorders are structural, metabolic, behavioral and functional disorders that are present at birth. Their manifestations are protean ranging from mild anomalies to life-threatening conditions.

Aim:

The objectives of this study were to describe the congenital anomalies in children seen at Federal Medical Center, Bida over a 12 month period, determine possible factors associated with these anomalies; and their short term outcome.

Subjects and Methods:

Children with clinically recognized congenital malformations were recruited consecutively over a 12 month period and socio-demographic, etiologic and other relevant clinical data were obtained. A detailed examination was also performed and abnormalities documented. The data was analyzed using Epi-info version 6 (Atlanta, USA). The Chi-square was used to identify significant differences for categorical variables. Mid-P and Fisher's exact tests were utilized as appropriate. A P < 0.05 was considered to be significant.

Results:

A total of 46 children with congenital anomalies were seen during the study period, all which were recruited into the study. The hospital based prevalence amongst neonates was 111/1000 neonates. The most common system affected was the digestive system(50.0%) followed by the central nervous system and head and neck anomalies. There was no significant difference in distribution of anomalies amongst the various ethnic groups. About 22% of families were consanguineous, all being first cousins and 8.7% of mothers were greater than 35 years of age. The case fatality rate for congenital malformations was 2.2%, while 60.9% were referred to other hospitals for further care.

Conclusion:

The study has demonstrated a wide variety of congenital anomalies in Bida, North-Central Nigeria with the digestive system anomalies being the most frequent. The findings of this study strengthen the need for empowerment of the institution in appropriate management of these disorders.

187 INCREASED EFFICIENCY OF DERIVING BOVINE STEM CELL-LIKE COLONIES USING VALPROIC ACID AND SMALL-MOLECULE COCKTAILS

Nonviral reprogramming of bovine embryonic and adult fibroblasts was undertaken using electroporation of a polycistronic plasmid carrying human reprogramming factors Oct4, Sox2, Lin28, and Nanog (Addgene Plasmid #20922). Because of difficulties encountered in reliably and reproducibly reprogramming bovine cells to a pluripotent state, several small-molecule combinations have been tested to support reprogramming. Previously, a combination of three molecules, (sodium butyrate, PD0325901 and SB431542; NaB-PD-SB) in induced pluripotent stem (iPS) medium [Minimum Essential Medium Alpha, 20% FBS, 1x insulin-transferrin-selenium (ITS), 2 mM Glutamax (Gibco, Grand Island, NY, USA), 100 μM nonessential amino acids (NEAA), 50 U mol–1 penicillin, 50 mg mL–1 streptomycin, 0.1 mM β-mercaptoethanol, 4 ng mL–1 human leukaemia inhibitory factor, and 10 ng mL–1 basic fibroblast growth factor] was found to accelerate the reprogramming process of bovine iPS cells, with colonies observed at 12 days post-electroporation, as opposed to 21 days without the addition of the small-molecule cocktail. The addition of 1 mM valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, in combination with the other small-molecule cocktail (NaB-PD-SB), was found to improve the reprogramming efficiency of bovine adult and embryonic fibroblasts, with colonies observed at Day 10 post-electroporation, and the average number of colonies present per 10-cm dish, rising from an average of 5 colonies observed in the NaB-PD-SB cocktail to 27 with the addition of VPA. Colonies grown in the presence of VPA had a consistent morphology, forming compact domed colonies consisting of small round cells with well-defined borders. It was observed that colonies growing in the presence of VPA tended to have a better defined border and grew larger in size than those grown in the presence of NaB-PD-SB alone. Colonies began to differentiate after 21 days and were no longer alkaline phosphatase positive after this time. Cells were either harvested for mRNA extraction or differentiated into embryoid bodies (EB). Expression of pluripotency genes, Oct4, Sox2, Klf4, Nanog, and Alkaline Phosphatase were significantly increased in the presence of VPA compared to nonreprogrammed somatic bovine fibroblasts, with expression profiles similar to those grown in the NaB-PD-SB cocktail. Embryoid bodies were analysed for gene expression of different germ layer markers, FOXA2 (endoderm), Nestin and TUBB3 (ectoderm), and Desmin (mesoderm) using quantitative RT–PCR. For both EBs derived from the NaB-PD-SB cocktail and those with VPA, at least one marker from each germ layer was present, demonstrating the potential potency of these cells. At least a 10-fold increase in expression of these was observed in comparison to somatic fibroblast cells. It is apparent that the addition of small molecules can assist in the reprogramming of bovine iPS cells, and addition of VPA to the cocktail results in more consistent putative bovine iPS colonies. Further work is needed to identify the causes for early differentiation of colonies in order to obtain fully reprogrammed pluripotent stem cells.

281 USE OF SMALL MOLECULES ENHANCES REPROGRAMMING SUCCESS IN BOVINE DERMAL FIBROBLASTS

Reprogramming of differentiated cells to induced pluripotency holds tremendous potential for livestock reproduction. Here we report use of small molecules to support the generation of stem cell-like colonies from bovine dermal fibroblasts that show characteristics of pluripotent cells. Reprogramming of bovine somatic cells was undertaken by introducing canonical reprogramming factors Oct4, Sox2, Klf4, and c-Myc through a lentiviral drug-inducible polycistronic vector. Several small molecules were tested to support reprogramming. A combination of 3 small molecules (sodium butyrate, PD0325901, and SB431542; NaB-PD-SB) in iPS medium [Minimum Essential Medium Alpha, 20% fetal bovine serum, 1× insulin-transferrin-selenium (ITS), 2 mM Glutamax, 100 µM NEAA, 50 U mol–1 penicillin, 50 mg mL–1 streptomycin, 0.1 mM β-mercaptoethanol, 4 ng mL–1 human leukemia inhibitory factor, and 10 ng mL–1 basic fibroblast growth factor] was found to accelerate the kinetics of the reprogramming process. Colonies appeared at 12 days of culture compared with 21 days in iPS medium alone (P < 0.01, n = 5). Colonies in NaB-PD-SB iPS medium had consistent morphology, with small cells in compact dome formations with well-defined colony borders. Cells were not passaged but were either harvested for mRNA extraction or differentiated into embryoid bodies. Gene expression of the reprogramming factors in stem cell-like colonies was confirmed by qRT-PCR, and further gene expression analysis revealed activation of Nanog and ALPL mRNA expression (P < 0.01, n = 2). Embryoid bodies were analysed for gene expression by quantitative RT-PCR. Silencing of the transgene was not observed in embryoid bodies despite withdrawal of the inducer doxycycline. Expression of the endoderm marker FOXA2, ectoderm markers NES and TUBB3, and mesoderm marker DES was strongly increased in embryoid bodies compared with non-reprogrammed bovine fibroblasts (P < 0.01, n = 2), confirming expression of marker genes for the 3 germ layers.

Calmodulin kinase II initiates arrhythmogenicity during metabolic acidification in murine hearts

Aim:

The multifunctional signal molecule calmodulin kinase II (CaMKII) has been associated with cardiac arrhythmogenesis under conditions where its activity is chronically elevated. Recent studies report that its activity is also acutely elevated during acidosis. We test a hypothesis implicating CaMKII in the arrhythmogenesis accompanying metabolic acidification.

Methods:

We obtained monophasic action potential recordings from Langendorff-perfused whole heart preparations and single cell action potentials (AP) using whole-cell patch-clamped ventricular myocytes. Spontaneous sarcoplasmic reticular (SR) Ca²⁺release events during metabolic acidification were investigated using confocal microscope imaging of Fluo-4-loaded ventricular myocytes.

Results:

In Langendorff-perfused murine hearts, introduction of lactic acid into the Krebs-Henseleit perfusate resulted in abnormal electrical activity and ventricular tachycardia. The CaMKII inhibitor, KN-93 (2 μm), reversibly suppressed this spontaneous arrhythmogenesis during intrinsic rhythm and regular 8 Hz pacing. However, it failed to suppress arrhythmia evoked by programmed electrical stimulation. These findings paralleled a CaMKII-independent reduction in the transmural repolarization gradients during acidosis, which previously has been associated with the re-entrant substrate under other conditions. Similar acidification produced spontaneous AP firing and membrane potential oscillations in patch-clamped isolated ventricular myocytes when pipette solutions permitted cytosolic Ca²⁺ to increase following acidification. However, these were abolished by both KN-93 and use of pipette solutions that held cytosolic Ca²⁺ constant during acidosis. Acidosis also induced spontaneous Ca²⁺ waves in isolated intact Fluo-4-loaded myocytes studied using confocal microscopy that were abolished by KN-93.

Conclusion:

These findings together implicate CaMKII-dependent SR Ca²⁺ waves in spontaneous arrhythmic events during metabolic acidification.

Has the ThinPrep method of cervical screening maintained its improvement over conventional smears in terms of specimen adequacy?

Liquid-based cytology (LBC) has replaced conventional smear assessment in many centers over recent years. In our laboratory this transfer took place in 1999. At that time we performed a split sample study comparing the conventional method of cervical smear evaluation with the ThinPrep system. This split sample study identified a dramatic improvement in specimen adequacy with LBC. While 11% of conventional preparations were reported as unsatisfactory and almost 9% were reported as suboptimal, evaluation of the same cases using LBC saw this combined figure reduced to 2.3%.

AIM

To evaluate whether this dramatic fall in unsatisfactory smears has been maintained with the use of LBC. The database for all smears reported for 2005 (100% LBC) was interrogated. The number of unsatisfactory reports was calculated. The reason for an unsatisfactory report was recorded for each case. The overall unsatisfactory rate was compared with that reported in the 1999 split sample study. A total of 41,312 smear tests were reported in 2005. 1,342 (3.25%) were reported as unsatisfactory. Our findings support the ongoing value of LBC in a routine cervical screening laboratory in terms of continuing to maintain a low rate of unsatisfactory smears.

The difficulty with audit of high grade cervical cytology in the absence of a national screening programme

Audit is an essential requirement of a cervical screening programme to ensure that laboratories are practising to agreed standards, and to ensure high quality patient care. The aim of this study was to assess the ability to audit high-grade cytology smear reports in a large cervical cytology laboratory in Ireland, where a nationally organised screening programme does not exist. Seven hundred and five questionnaires were forwarded to smear takers requesting follow-up data regarding high grade smear results from 2003. Seventy-four percent of the questionnaires were returned containing insufficient data, with a "don't know result" rate of >50%. This attempt at detailed audit took place 5 years ago. Annual internal audit continues to the best of the laboratory's ability but the situation, in terms of a centralised database in the context of a national screening programme, remains unchanged. A National Cervical Cytology Screening Programme is essential to centralise patient data, to allow for improved patient care, patient follow-up and audit.

A review of the evidence on the effects and costs of implantable cardioverter defibrillator therapy in different patient groups, and the modelling of cost-effectivenessan cost-utility for these groups in a UK context

OBJECTIVES

To update the systematic review evidence on the effectiveness, health-related quality of life (HRQoL) and cost-effectiveness of implantable cardioverter defibrillators (ICDs); compilation of new data on the service provision in the UK; and on the clinical characteristics, survival, quality of life and costs of ICD patients in the UK, and a new cost-effectiveness model using both international RCT and UK-specific data.

DATA SOURCES

Electronic databases searched from November 1999 to March 2003, this was supplemented by a systematic review of research published during 2003-5. Survey data.

REVIEW METHODS

Studies were selected and assessed. A survey of ICD centres was carried out. Basic data were obtained from two major implanting centres including 535 patients (approximately 10% of overall UK activity) implanted between 1991 and 2002, and retrieval of fuller data, on patient characteristics, management and resource use, from patient notes for a sample of 426 patients was attempted. A cross-sectional survey collected HRQoL data (using the Nottingham Health Profile, Short Form 36, Hospital Anxiety and Depression questionnaire, EuroQoL 5 Dimensions and disease-specific questions) on a sample of 229 patients. A Markov model combined UK patient data with data from published randomised controlled trials (RCTs) to estimate incremental costs per life-year or quality-adjusted life-year (QALY) gained.

RESULTS

None of the economic analyses in the studies found could be directly applied to the UK. The multiple sources of routine data available (including the national ICD database) provide an imperfect picture of the need for and use of ICDs. Implantation rates have been rising to a rate of around 20 per million population. Mean age is increasing and most ICDs are implanted into men aged 45-74 years. There is significant geographical variation. A survey of 41 UK centres provided additional evidence, particularly of variation in level of activity and resourcing. Most detailed data were obtained for 380 patients (89%). The postal survey produced a 73% response rate. Demographic characteristics of these patients were similar to ICD recipients in the UK as a whole and patients included in secondary prevention RCTs. Mean actuarial survival at 1, 3 and 5 years was 92%, 86% and 71%, respectively. Patient age at implantation and functional status significantly affected survival. Levels of most of the HRQoL measures were lower than for a UK general population. There was no evidence of a change with time from implantation. Patients who had suffered ICD shocks had significantly poorer HRQoL. Most patients nevertheless expressed a high level of satisfaction with ICD therapy. Mean initial costs of implantation showed little variation between centres (23,300 pounds versus 22,100 pounds) or between earlier and more recent implants. There appeared to be greater variation between patients presenting along different pathways. Postdischarge costs (tests, medications and follow-up consultations) and costs of additional hospitalisations were also calculated. Using the Markov model it was found that over a 20-year horizon, mean discounted incremental costs were 70,900 pounds (35,000-142,400 pounds). Mean discounted gain was 1.24 years (0.29-2.32) or 0.93 QALYs. Cost-effectiveness was most favourable for men aged over 70 years with a left ventricular ejection fraction (LVEF) below 35%. If the treatment effect were to continue, then the cost per life-year over a lifetime might fall to around 32,000 pounds. Five RCTs of ICDs, a meta-analysis and, a cost-effectiveness analysis of ICDs used in primary prevention, and a meta-analysis of ICDs in patients with non-ischaemic cardiomyopathy have been published recently. These trials provide confirmation of survival benefit of ICDs used in primary prevention in both ischaemic and non-ischaemic cardiomyopathy patients. Costs per QALY ranged from US$34,000 in older trials to controls being both less expensive and more effective (CABG Patch, DINAMIT). More recent trials estimated cost per QALY between $50,300 and $70,200. The inconsistency in evidence for a HRQoL benefit has not been resolved and further work on risk stratification is necessary.

CONCLUSIONS

The evidence of short- to medium-term patient benefit from ICDs is strong but cost-effectiveness modelling indicates that the extent of that benefit is probably not sufficient to make the technology cost-effective as used currently in the UK. One reason is the high rates of postimplantation hospitalisation. Better patient targeting and efforts to reduce the need for such hospitalisation may improve cost-effectiveness. Further cost-effectiveness modelling, underpinned by an improved ICD database with reliable long-term follow-up, is required. The absence of a robust measure of the incidence of sudden cardiac death is noted and this may be an area where further organisational changes with improved data collection would help.

Telomerase activity in proximal and distal gastric neoplastic and preneoplastic lesions using immunohistochemical detection of hTERT

BACKGROUND

The incidence of distal (corpus and antrum) gastric adenocarcinoma is decreasing with a simultaneous increase in incidence of proximal (cardia) adenocarcinoma. Epidemiological studies suggest that they may represent different diseases but corroborative molecular data are scarce. Intestinal metaplasia may have a lower malignant potential in the proximal stomach but regardless of the locations, its specificity as a predictor of carcinoma is low.

AIMS

The aim of this study was to establish whether human telomerase reverse transcriptase expression differs at various points in proximal versus distal gastric carcinogenesis and to test the utility of human telomerase reverse transcriptase expression as a marker of cancer risk in intestinal metaplasia.

MATERIAL AND METHODS

Wax-embedded tissue from proximal and distal stomach including normal mucosa (n=86), intestinal metaplasia (n=83) and carcinoma (n=101) were used and slides were immunostained for human telomerase reverse transcriptase and pRb and scored semi-quantitatively.

RESULTS

The results showed that in both proximal and distal stomach, human telomerase reverse transcriptase expression rates increased from normal mucosa to cancer. High rates of human telomerase reverse transcriptase expression were seen in the proliferative zones of glands in intestinal metaplasia. In both the locations, loss of pRb expression correlated with higher human telomerase reverse transcriptase expression.

CONCLUSIONS

In conclusion, telomerase activity appears to be an early event in both proximal and distal gastric carcinogenesis and human telomerase reverse transcriptase is expressed in intestinal metaplasia. Telomerase re-expression may be facilitated by pRb inactivation.

Borderline nuclear change in cervical smears: five-year follow-up

Borderline nuclear changes (BNC) account for 5-20% of cervical smears, and their outcome is unpredictable. Current management involves repeat smears at 6-mo intervals, for a further 12 mo with referral for colposcopy, if the changes persist. Given the uncertainty surrounding the natural history of BNC and the claim that many patients are further investigated unnecessarily and potentially "overtreated," the aim of this study was to determine the outcome for patients with a diagnosis of BNC to define whether the management protocol is appropriate for this patient group in our laboratory. A total of 808 patients with BNC were followed up. There was a 4.05% progression to high-grade dyskaryosis, and most of these were detected within the first year of follow-up. This at least justifies the early and intense follow-up of this patient group until a reliable "triage tool" is adopted to pre-select those patients with BNC who will progress or revert to negative.

Cytokeratin 7/20 and mucin expression patterns in oesophageal, cardia and distal gastric adenocarcinomas

AIMS

The current study examined cytokeratin (CK)7 and 20 as well as MUC1-6 immunoprofiles in oesophageal, gastric and gastro-oesophageal junction (GOJ) adenocarcinomas. The aim was to compare expression patterns in these locations as aids to accurate classification of these morphologically similar carcinomas which all may involve the GOJ.

METHODS AND RESULTS

Tissue microarrays were constructed using tissue from 14 oesophageal, 78 gastric and 39 GOJ adenocarcinomas. Sections were immunostained with CK7, CK20, MUC1, MUC2, MUC5AC and MUC6. The results of this study showed no differences in CK7 and CK20 expression patterns in the three locations. MUC2 expression was higher proximally (43% of oesophageal, 28% of GOJ and 17% of gastric carcinomas) and MUC6 expression was higher distally (7% of oesophageal, 28% of GOJ and 15% of gastric carcinomas). MUC1 expression was associated with higher pTNM-stage.

CONCLUSIONS

CK 7/20 profiles have no role in distinguishing tumours of the three locations. Mucin expression patterns differed in oesophageal and gastric adenocarcinomas, although not sufficiently to classify individual cases. GOJ adenocarcinomas showed a mucin expression pattern that was partly 'gastric', and partly 'oesophageal'. MUC1 expression was associated with a higher pTNM stage.

Well differentiated fetal adenocarcinoma of the lung in a 29 year old woman

This report describes a case of well differentiated fetal adenocarcinoma of the lung in a 29 year old female smoker. The histological pattern and immunohistochemical profile were consistent with well differentiated fetal adenocarcinoma and the patient made an uneventful postoperative recovery with no recurrence after 18 months. This neoplasm is a rare lung tumour that is composed of glycogen rich neoplastic glands and tubules that resembles fetal lung at 10 to 15 weeks of gestation. It is important to identify this rare variant of adenocarcinoma because it is a low grade malignancy with low associated mortality.

Biopsy of a biopsy: validation of immunoprofiling in gastric cancer biopsy tissue microarrays

AIMS

Tissue microarrays offer an efficient way of examining a large number of tumour cases on a single glass slide. A major concern, however, is tumour heterogeneity. Also, the use of tissue microarrays in biopsy material is unexplored. The purpose of the present study was to assess the possibility and validity of arraying three 0.6-mm cores per case in endoscopic gastric cancer biopsies for immunophenotyping.

METHODS AND RESULTS

Thirty-eight cases were studied with immunohistochemical staining for p53, CD44v6 and vascular endothelial growth factor. Full tissue sections were compared with triple core-tissue microarrays. Thirty-six cases contained three cores with tumour, one case contained two cores with tumour and one case contained only a single core with viable tumour and was excluded. Three further cores had been lost from three separate cases on the sections for immunohistochemistry. kappa values for whole-sections versus tissue microarrays ranged between 0.77 and 0.94. p53 immunohistochemical staining (interpretation as + or -) yielded the best result with only 1/37 mismatches, whereas CD44v6 (graded both for intensity and extent) showed 3/37 mismatches. The small depth of tissue in cores from biopsies necessitates all cores being arrayed flush with the face of the recipient wax block for maximizing the number of sections available. Compared with the first section over 30 additional 4- micro m sections were available before the first case (with one core left) had to be excluded and 80 sections before half the tissue cores were lost.

CONCLUSIONS

It is impracticable to array more than 120-150 cores per block. Tissue microarray with three cores per case is feasible and valid for studying biopsy material.

Comparative study: conventional cervical and ThinPrep Pap tests in a routine clinical setting

The conventional Papanicolaou smear is associated with variable false positive and false negative rates, difficulties with interpretation and high unsatisfactory and suboptimal rates. Newer fluid-based methods such as the ThinPrep 2000 system (Cytyc Corp., Boxborough, MA) are said to overcome these difficulties. The aim of this study was to compare the conventional smear with the ThinPrep method in a busy, routine cytology screening laboratory setting. One thousand split samples were evaluated. Using ThinPrep, the results showed an increased sensitivity and a dramatic improvement in specimen adequacy, with a combined 17.2% reduction in 'unsatisfactory' and 'suboptimal' reports. Screening time per slide was also reduced to 3-4 min. In conclusion, we report an increase in sensitivity, a reduction in screening time and a dramatic improvement in specimen adequacy with the ThinPrep method.

APC gene expression in gastric carcinoma: an immunohistochemical study

Gastric carcinoma is one of the most common malignancies worldwide, particularly in Japan and China. Inactivation of the adenomatous polyposis coli ( ) gene, a tumor suppressor gene, has been shown to play a significant role in the development of colorectal carcinoma, and it has been suggested that it may play a role throughout the digestive tract, including the stomach. This study assesses gene expression in normal gastric mucosa and gastric adenocarcinoma using an antibody to the C-terminal region. One hundred twenty cases of gastric adenocarcinoma were examined from the files of Beaumont Hospital, Dublin, Ireland, and China Medical University, Shenyang, China. Ninety-one cases were informative. Of these, 78% revealed loss of staining. Loss of staining in adenocarcinoma showed no association with tumor type, tumor, stage or patient nationality. Loss of staining was also found in nine of 35 cases (26%) of intestinal metaplasia. In conclusion, loss of the gene, as determined by immunohistochemical staining, appears to be an early event in gastric carcinogenesis. Immunohistochemistry is a sensitive method for detection of this loss.

CD44V6 in gastric carcinoma: a marker of tumor progression

CD44 is a group of cell surface molecules involved in cell-cell and cell-matrix interactions. CD44 spliced variants (CD44V) have been found to enhance the metastatic potential of rat tumors. Tumors from the breast, colon, and thyroid express many alternatively spliced products; nonneoplastic tissues do not. Some authors suggest that CD44V5 and V6 may play a role in gastric carcinoma. The aim of the current study was to investigate the role of CD44V6 as a prognostic marker and predictor of metastatic potential in gastric carcinomas. One hundred fifty-five cases of gastric adenocarcinomas were studied: 36 cases of early (EGC), 19 cases of intermediate (MGC), and 100 cases of advanced gastric adenocarcinomas (AGC). A monoclonal antibody against CD44V6 (R&D) was used. CD44V6 expression was positively correlated with advanced stage (P = 0.05). Strong positivity was only detected in those cases of AGC with metastases. Patients with CD44V6 positive tumors revealed a lower 3- and 5-year survival rate (P = 0.0002). Immunohistochemical detection of CD44V6 could now be used as an indicator of tumor progression in biopsies of patients with gastric carcinoma.

A POLYGEN-adjuvanted killed Neospora caninum tachyzoite preparation failed to prevent foetal infection in pregnant cattle following i.v./i.m. experimental tachyzoite challenge

Cattle immunised with a POLYGEN-adjuvanted killed Neospora caninum tachyzoite preparation were previously shown to produce interferon (IFN)-gamma at levels similar to those of tachyzoite-infected cattle. In view of the critical role of IFN-gamma in resistance of mice to N. caninum infection, these results prompted us to test the POLYGEN-adjuvanted preparation in pregnant cattle to determine whether it will be able to prevent foetal infection following an experimental tachyzoite challenge. Seven heifers were immunised at 35 and 63 days of gestation with the POLYGEN-adjuvanted preparation, while five heifers were inoculated with POLYGEN alone at the same days of gestation. Four weeks later, all heifers were challenged with a combined i.v./i.m. inoculation of tachyzoites. The same challenge was given to seven unimmunized heifers at the same stage of gestation. An additional unimmunized heifer was inoculated with uninfected monolayer cell culture material. All challenged heifers, immunized and unimmunized, had infected foetuses. Immunized heifers developed both parasite-specific humoral and cellular immune responses, characterised by increased IFAT titres, a predominant IgG1 response, elevated lymphoproliferative response and IFN-gamma production. Following tachyzoite challenge, they developed an anamnestic humoral response and produced similar amounts of IgG1 and IgG2 antibodies, but did not have an anamnestic cellular immune response. The lack of anamnestic cellular immune response and/or the large i.v/i.m tachyzoite inoculum may have contributed to the failure of the preparation.

Effects of estrogen replacement therapy on the circadian rhythms of serum cortisol and body temperature in postmenopausal women

Estrogen replacement therapy (ERT) seems to enhance longevity in women. Both gender and aging have been shown to influence the regulation of circadian rhythms, yet little is known about the effect of ERT on circadian regulation. The aim of this study was to determine the effects of ERT (oral conjugated estrogen: Premarin, 0.625 mg) for 6-8 weeks on circadian serum cortisol by continuous blood sampling every 15 min for 24 h with simultaneous measurements of body temperature in six healthy postmenopausal women (range, 54-61 years). The results are presented as median values (range in quartiles). The circadian amplitude of cortisol increased during ERT from 20.20 (18.35, 23.61) to 25.97 (24.94, 27.74) microg/dL (p = 0.016), whereas the timing of nocturnal nadir and morning acrophase did not differ significantly. ERT lowered the 24-h body temperature from 37.03 degrees C (36.95 degrees C, 37.07 degrees C) to 36.90 degrees C (36.77 degrees C, 36.97 degrees C) (p = 0.038), but did not alter the peak and trough body temperatures significantly. These findings are noteworthy because the increased circadian amplitude of serum cortisol during ERT contrasts with the reduction in circadian amplitude seen with normal aging. The reduction in body temperature confirms the regulatory effect of ERT in thermoregulation and has implications regarding the correlation between basal metabolic rate and life span.

Malignant lymphoma of the cervix. An unusual presentation and a rare disease

Malignant lymphomas arising in the uterus are uncommon and are more commonly seen in the cervix than the corpus. Involvement of the cervix as part of a systemic lymphoma is more common than primary lymphoma, but the cervix as the site of presentation is unusual. We report two cases of malignant lymphoma of the cervix. The first patient, a 52-year-old woman, was referred to colposcopy following persistent low grade dyskaryosis on cervical cytology. At colposcopy a Lletz biopsy was performed and a diagnosis of CIN 1 and focal CIN 2 was made. In addition the subepithelial zone revealed a non-Hodgkin's (NHL) B-cell follicular lymphoma. The patient was subsequently staged as NHL Stage 3E. The second patient, a 35-year-old woman, was referred to the gynaecology department with a history of abnormal vaginal bleeding and two abnormal smears. Subsequent cervical biopsy revealed a high grade, large cell, malignant lymphoma, diffuse, B-cell. The patient was staged as Stage IE. Primary lymphoma of the uterine cervix as illustrated in the second case is very unusual. One case had negative cytology and one case had abnormal cells of uncertain origin. This highlights the difficulty of diagnosing cervical lymphoma, a rare but treatable malignancy, on cytology and suggests that cervical biopsy is needed for the confirmation of the diagnosis.

A community-based study of the epidemiology of Helicobacter pylori infection and associated asymptomatic gastroduodenal pathology

OBJECTIVES

To document the epidemiology of Helicobacter pylori infection in a normal population, to assess asymptomatic H. pylori positive individuals for the presence of gastroduodenal disease, and to compare the macroscopic and microscopic findings at endoscopy in this group with those of patients presenting with dyspepsia.

DESIGN/METHODS

Serum was collected from blood donors and assessed for the presence of anti-H. pylori IgG antibodies. A randomly selected group of asymptomatic blood donors and dyspeptic patients underwent endoscopy.

RESULTS

The seroprevalence of H. pylori in 1000 subjects was 43.0%. The prevalence of infection increased from 29% in 18-30 year olds to 62% in 46-60 year olds (P < 0.01). The infection was more prevalent in individuals from social classes IV and V (50.0%) than social classes I and II (36.9%) (P < 0.01). There was no difference between the H. pylori positive asymptomatic individuals (n = 37) and matched dyspeptic patients (n = 29) at endoscopy with regard to duodenal ulcer (13.5% vs. 17.2%) or gastroduodenal erosions (24.3% vs. 20.7%) while 5.4% of the former had gastro-oesophageal reflux compared to 27.6% of the latter. Overall, 56.8% of the H. pylori positive asymptomatic group had a normal macroscopic endoscopy compared with 31% of the dyspeptic group. Histology of the gastric mucosa did not reveal any significant differences between the two groups. In H.pylori negative asymptomatic individuals (n = 13) 92.3% had a normal endoscopy (7.7% had grade I gastro-oesophageal reflux) compared with 61.5% of a matched dyspeptic group (n = 13).

CONCLUSION

H.pylori infection, symptomatic and asymptomatic, is associated with significant pathology, and screening for the infection may be indicated for the prevention of gastroduodenal diseases.

Anginal headache and its basis

A case is presented of angina manifesting itself initially solely as vertex and occipital headache, accompanied by EKG changes, provoked by exercise and relieved by rest. It was totally relieved by coronary bypass surgery and, later, by angioplasty. Its mechanism is probably a variation on the neural convergence usually invoked to explain the more typical chest pain angina.

Ear-nose-throat abnormalities in the CHARGE association

A comprehensive evaluation of the otolaryngological abnormalities in 50 patients with colobomata, heart defect, atresia of the choanae, retarded growth or development, genital hypoplasia, and ear anomalies or deafness (CHARGE) was performed. All the patients had ear abnormalities; 96% (48/50) had malformed pinnae, and 54% (27/50) had facial nerve palsies. Only 8% (4/50) had normal hearing, the commonest hearing defect being severe conductive or mixed loss. Eighty-four percent (42/50) of computed tomographic scans of the temporal bone were abnormal, the characteristic abnormality being the combination of a hypoplastic incus and absent semicircular canals. Eighty-six percent (43/50) of patients had upper airway abnormalities. Posterior choanal abnormalities occurred in 56% (28/50), and 42% (21/50) had retrognathia leading to intubation difficulties. Laryngotracheal abnormalities occurred in 38% (19/50), and 14% (7/50) required tracheostomies. Careful upper airway assessment is essential to avoid potentially lethal complications such as aspiration.

Sex-dependent loss of projection neurons involved in avian song learning

In zebra finches, only males sing, and the neural regions controlling song exhibit prominent, hormone-induced sex differences in neuron number. In order to understand how sexual differentiation regulates neuron number within one song nucleus, the lateral magnocellular nucleus of the anterior neostriatum (IMAN), we studied the development of sex differences among IMAN neurons that project to the robust nucleus of the archistriatum (RA). The IMAN is implicated in song learning, and previous ontogenetic studies have indicated that males lose over 50% of their IMAN neurons during the juvenile song learning period. Based on developmental changes in both the extent of androgen accumulation within the IMAN and its appearance in Nissl-stained tissue, it had been hypothesized that IMAN neuron loss was even greater in young females, resulting in sex differences in neuron number. However, this hypothesis has not been tested directly because the Nissl-stained boundaries of the IMAN sometimes are ambiguous in young animals, and are not evident at all in adult females. To circumvent these problems, we employed the retrograde tracer fast blue to study the development of IMAN neurons defined on the basis of their projections to the RA. We find that the number of these IMAN-RA projection neurons is much greater in adult males than in females, and that this sex difference develops during the juvenile period of sexual differentiation and song learning because a significant number of these neurons are lost in females but not in males. With respect to sexual differentiation, we conclude that masculinization (which is stimulated by the hormone estradiol) promotes the retention of IMAN-RA projection neurons. In addition, our results indicate that any loss of IMAN neurons that may occur in young males does not include cells projecting to the RA.