Association of a device-based remote management heart failure pathway with outcomes: TriageHF Plus real-world evaluation

AIMS

Clinical pathways have been shown to improve outcomes in patients with heart failure (HF). Although patients with HF often have a cardiac implantable electronic device, few studies have reported the utility of device-derived risk scores to augment and organize care. TriageHF Plus is a device-based HF clinical pathway (DHFP) that uses remote monitoring alerts to trigger structured telephone assessment for HF stability and optimization. We aimed to evaluate the impact of TriageHF Plus on hospitalizations and describe the associated workforce burden.

METHODS AND RESULTS

TriageHF Plus was a multi-site, prospective study that compared outcomes for patients recruited between April 2019 and February 2021. All alert-triggered assessments were analysed to determine the appropriateness of the alert and the workload burden. A negative-binomial regression with inverse probability treatment weighting using a time-matched usual care cohort was applied to estimate the effect of TriageHF Plus on non-elective hospitalizations. A post hoc pre-COVID-19 sensitivity analysis was also performed. The TriageHF Plus cohort (n = 443) had a mean age of 68.8 ± 11.2 years, 77% male (usual care cohort: n = 315, mean age of 66.2 ± 14.5 years, 65% male). In the TriageHF Plus cohort, an acute medical issue was identified following an alert in 79/182 (43%) cases. Fifty assessments indicated acute HF, requiring clinical action in 44 cases. At 30 day follow-up, 39/66 (59%) of initially symptomatic patients reported improvement, and 20 (19%) initially asymptomatic patients had developed new symptoms. On average, each assessment took 10 min. The TriageHF Plus group had a 58% lower rate of hospitalizations across full follow-up [incidence relative ratio: 0.42, 95% confidence interval (CI): 0.23-0.76, P = 0.004]. Across the pre-COVID-19 window, hospitalizations were 31% lower (0.69, 95% CI: 0.46-1.04, P = 0.077).

CONCLUSIONS

These data represent the largest real-world evaluation of a DHFP based on multi-parametric risk stratification. The TriageHF Plus clinical pathway was associated with an improvement in HF symptoms and reduced all-cause hospitalizations.

Clinical Pathways Guided by Remotely Monitoring Cardiac Device Data: The Future of Device Heart Failure Management?

Research examining the utility of cardiac device data to manage patients with heart failure (HF) is rapidly evolving. COVID-19 has reignited interest in remote monitoring, with manufacturers each developing and testing new ways to detect acute HF episodes, risk stratify patients and support self-care. As standalone diagnostic tools, individual physiological metrics and algorithm-based systems have demonstrated utility in predicting future events, but the integration of remote monitoring data with existing clinical care pathways for device HF patients is not well described. This narrative review provides an overview of device-based HF diagnostics available to care providers in the UK, and describes the current state of play with regard to how these systems fit in with current HF management.

Use of a device-based remote management heart failure care pathway is associated with reduced hospitalization and improved patient outcomes: TriageHF Plus real-world evaluation

Background

Heart failure (HF) is a leading cause of hospital admission. However, prompt identification of worsening HF using implantable device data and proactive intervention may reduce hospitalizations.

The validated TriageHF algorithm in enabled ICD/CRT devices uses sensor data to risk stratify patients for HF hospitalization in the next 30 days. TriageHF Plus is a novel device-based HF care pathway (DHFP) that uses “high” risk status as the trigger for remote intervention (see Figure 1 for pathway overview). Outcomes after DHFP implementation in a clinical setting have not been examined.

Purpose

To evaluate the impact of TriageHF Plus clinical pathway on hospitalisation rates.

Methods

A prospective, multi-center evaluation comparing monthly hospitalization rates for patients enrolled in a DHFP with a concurrent standard of care (SoC) cohort and characterizing staffing resources necessary to implement the DHFP. The DHFP cohort received telephonic assessment and guideline-directed clinical care upon transition to high-risk status. Propensity scores (PS) were applied to DHFP and SoC cohorts to allow unbiased comparison. A negative binomial model was fitted to the monthly number of all-cause hospitalizations with treatment group (DHFP vs. SoC) as a covariate, using PS as weights.

Results

Between 09/11/2019 and 06/24/2021, 758 patients were included in the study (443 DHFP, 315 SoC). Proportion CRT 76%/ 89% and LVEF <50% 78%/ 66% for DHFP/ SoC, respectively.

196 high risk transmissions prompted telephone assessment, with successful contact in 182; of which, 79 (43%) identified an explanatory acute medical issue. A secondary intervention was undertaken in 44/79 (56%). High risk transmissions took on average 19 minutes per clinical assessment (initial telephone triage and 30 day follow up). The rate of hospitalizations was 58% lower in the DHFP group, compared with SoC, after PS adjustment (IRR 0.42, 95% CI: 0.23, 0.76, p=0.004), see Figure 2. Sensitivity analyses showed Covid-19 had little effect on results.

Conclusions

This is the first prospective, real-world evaluation of a device-based HF care pathway to report a reduction in hospitalizations and does so with minimal staffing time. Integrated into existing HF services, device-based remote monitoring of HF patients can improve outcomes.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Medtronic

Remotely Monitored Cardiac Implantable Electronic Device Data Predict All-Cause and Cardiovascular Unplanned Hospitalization

Background Unplanned hospitalizations are common in patients with cardiovascular disease. The "Triage Heart Failure Risk Status" (Triage-HFRS) algorithm in patients with cardiac implantable electronic devices uses data from up to 9 device-derived physiological parameters to stratify patients as low/medium/high risk of 30-day heart failure (HF) hospitalization, but its use to predict all-cause hospitalization has not been explored. We examined the association between Triage-HFRS and risk of all-cause, cardiovascular, or HF hospitalization. Methods and Results A prospective observational study of 435 adults (including patients with and without HF) with a Medtronic Triage-HFRS-enabled cardiac implantable electronic device (cardiac resynchronization therapy device, implantable cardioverter-defibrillator, or pacemaker). Cox proportional hazards models explored association between Triage-HFRS and time to hospitalization; a frailty term at the patient level accounted for repeated measures. A total of 274 of 435 patients (63.0%) transmitted ≥1 high HFRS transmission before or during the study period. The remaining 161 patients never transmitted a high HFRS. A total of 153 (32.9%) patients had ≥1 unplanned hospitalization during the study period, totaling 356 nonelective hospitalizations. A high HFRS conferred a 37.3% sensitivity and an 86.2% specificity for 30-day all-cause hospitalization; and for HF hospitalizations, these numbers were 62.5% and 85.6%, respectively. Compared with a low Triage-HFRS, a high HFRS conferred a 4.2 relative risk of 30-day all-cause hospitalization (8.5% versus 2.0%), a 5.0 relative risk of 30-day cardiovascular hospitalization (3.6% versus 0.7%), and a 7.7 relative risk of 30-day HF hospitalization (2.0% versus 0.3%). Conclusions In patients with cardiac implantable electronic devices, remotely monitored Triage-HFRS data discriminated between patients at high and low risk of all-cause hospitalization (cardiovascular or noncardiovascular) in real time.

Remote monitoring data from cardiac implantable electronic devices predicts all-cause mortality

Aims

To determine if remotely monitored physiological data from cardiac implantable electronic devices (CIEDs) can be used to identify patients at high risk of mortality.

Methods and results

This study evaluated whether a risk score based on CIED physiological data (Triage-Heart Failure Risk Status, ‘Triage-HFRS’, previously validated to predict heart failure (HF) events) can identify patients at high risk of death. Four hundred and thirty-nine adults with CIEDs were prospectively enrolled. Primary observed outcome was all-cause mortality (median follow-up: 702 days). Several physiological parameters [including heart rate profile, atrial fibrillation/tachycardia (AF/AT) burden, ventricular rate during AT/AF, physical activity, thoracic impedance, therapies for ventricular tachycardia/fibrillation] were continuously monitored by CIEDs and dynamically combined to produce a Triage-HFRS every 24 h. According to transmissions patients were categorized into ‘high-risk’ or ‘never high-risk’ groups. During follow-up, 285 patients (65%) had a high-risk episode and 60 patients (14%) died (50 in high-risk group; 10 in never high-risk group). Significantly more cardiovascular deaths were observed in the high-risk group, with mortality rates across groups of high vs. never-high 10.3% vs. <4.0%; P = 0.03. Experiencing any high-risk episode was associated with a substantially increased risk of death [odds ratio (OR): 3.07, 95% confidence interval (CI): 1.57–6.58, P = 0.002]. Furthermore, each high-risk episode ≥14 consecutive days was associated with increased odds of death (OR: 1.26, 95% CI: 1.06–1.48; P = 0.006).

Conclusion

Remote monitoring data from CIEDs can be used to identify patients at higher risk of all-cause mortality as well as HF events. Distinct from other prognostic scores, this approach is automated and continuously updated.

Ambulatory intravenous furosemide for decompensated heart failure: safe, feasible, and effective

Aims

This study aims to establish the feasibility, safety, and efficacy of outpatient intravenous (IV) diuretic treatment for the management of decompensated heart failure (HF) for patients enrolled in the HeartFailure@Home service.

Methods and results

We retrospectively analysed the clinical episodes of decompensated HF for patients enrolled in the HeartFailure@Home service, managed by ambulatory IV diuretic treatment either at home or on a day‐case unit. A control group consisting of HF patients admitted to hospital for IV diuretics (standard‐of‐care) was also evaluated. In total, 203 episodes of decompensated HF (n = 154 patients) were evaluated. One hundred and fourteen episodes in 79 patients were managed exclusively by the ambulatory IV diuretic service—78 (68.4%) on a day‐case unit and 36 (31.6%) domiciliary; 84.1% of patient episodes under the HF@Home service were successfully managed entirely in an out‐patient setting without hospitalization. Eleven patients required admission in order to administer higher doses of IV diuretics than could be provided in the ambulatory setting. During follow‐up, there were 20 (17.5%) 30 day re‐admissions with HF or death in the ambulatory IV group and 29 (32.6%) in the standard‐of‐care arm (P = 0.02). There was no difference in 30 day HF readmissions between the two groups (14.9% ambulatory vs. 13.5% inpatients, P = 0.8), but 30 day mortality was significantly lower in the ambulatory group (3.5% vs. 21.3% inpatients, P < 0.001).

Conclusions

Outpatient ambulatory management of decompensated HF with IV diuretics given either on a day case unit or in a domiciliary setting is feasible, safe, and effective in selected patients with decompensated HF. This should be explored further as a model in delivering HF services in the outpatient setting during COVID‐19.

Triage-HF Plus: a novel device-based remote monitoring pathway to identify worsening heart failure

Aims

Remote monitoring of patients with physiological data derived from cardiac implanted electronic devices (CIEDs) offers potential to reconfigure clinical services. The ‘Heart Failure Risk Score' (HFRS) uses input from integrated device physiological monitoring to risk‐stratify patients as low‐risk, medium‐risk, or high‐risk of a heart failure event in the next 30 days. This study aimed to evaluate a novel clinical pathway utilizing a combination of CIED risk‐stratification and telephone triage to identify patients with worsening heart failure (WHF).

Methods and results

A prospective, single‐centre, real‐world evaluation of the ‘Triage‐HF Plus' clinical pathway (HFRS in combination with telephone triage) over a 27 month period. One hundred and fifty‐seven high‐risk HFRS transmissions were referred for telephone triage assessment. Interventions were at the discretion of the clinical assessor acting in accordance with clinical guidelines. An additional 3month consecutive sample of low and medium HFRS transmissions (control group) were also contacted for telephone triage assessment (n = 98). Successful telephone contact was made in 127 (81%) of referred high‐risk HFRS cases: 71 (55.9%) were confirmed to have WHF requiring intervention; 19 (14.9%) had an alternative acute medical problem; one patient had been recently discharged from hospital with WHF; and 36 (28.0%) had no apparent cause for the high score. In the control group, only one patient had symptoms of WHF. The sensitivity and specificity of CIED‐based remote monitoring to identify WHF 98.6% (92.5–100.0%) and 63.4% (55.2–71.0%), respectively.

Conclusions

The Triage‐HF Plus clinical pathway is a potentially useful remote monitoring tool for patients with heart failure and in situ CIEDs.

Potential prognostic factors for delayed healing of common, non-traumatic skin ulcers: A scoping review

Healing of non-traumatic skin ulcers is often suboptimal. Prognostic tools that identify people at high risk of delayed healing within the context of routine ulcer assessments may improve this, but robust evidence on which factors to include is lacking. Therefore, we scoped the literature to identify which potentially prognostic factors may warrant future systematic reviews and meta-analyses. We conducted electronic searches in MEDLINE and Embase to identify studies in English published between 1997 and 2017 that tested the association between healing of the three most common non-traumatic skin ulcers encountered by health care professionals (venous leg, diabetic foot, and pressure ulcers) and patient characteristics, ulcer characteristics, and results from clinical investigations. We included 42 studies that investigated factors which may be associated with the healing of venous leg ulcers (n = 17), diabetic foot ulcers (n = 15), and pressure ulcers (n = 10). Across ulcer types, ulcer characteristics were most commonly reported as potential prognostic factors for healing (n = 37), including the size of the ulcer area (n = 29) and ulcer duration at first assessment (n = 16). A total of 35 studies investigated the prognostic value of patient characteristics (n = 35), including age (n = 31), gender (n = 30), diabetes (n = 22), smoking status (n = 15), and history of deep vein thrombosis (DVT) (n = 13). Of these studies, 23 reported results from clinical investigations as potential prognostic factors, with the majority regarding vessel quality. Age, gender, diabetes, smoking status, history of DVT, ulcer area, and ulcer duration at time of first assessment warrant a systematic review and meta-analysis to quantify their prognostic value for delayed ulcer healing.

Safety of sedation for gastrointestinal endoscopy in a group of university-affiliated hospitals: a prospective cohort study

BACKGROUND

Service models for gastrointestinal endoscopy sedation must be safe, as endoscopy is the most common procedure performed under sedation in many countries. The aim of this prospective cohort study was to determine the patient risk profile, and incidence of and risk factors for significant unplanned events, in adult patients presenting for gastrointestinal endoscopy in a group of university-affiliated hospitals where most sedation is managed by anaesthetists.

METHODS

Patients aged ≥18 yr presenting for elective and emergency gastrointestinal endoscopy under anaesthetist-managed sedation at nine hospitals affiliated with the University of Melbourne, Australia, were included. Outcomes included significant airway obstruction, hypoxia, hypotension and bradycardia; unplanned tracheal intubation; abandoned procedure; advanced life support; prolonged post-procedure stay; unplanned over-night admission and 30-day mortality.

RESULTS

2,132 patients were included. Fifty percent of patients were aged >60 yr, 50% had a BMI >27 kg m ^-2, 42% were ASA physical status III-V and 17% were emergency patients. The incidence of significant unplanned events was 23.0% (including significant hypotension 11.8%). Significant unplanned intraoperative events were associated with increasing age, BMI <18.5 kg m ^-2, ASA physical status III-V, colonoscopy and planned tracheal intubation. Thirty-day mortality was 1.2% (0.2% in electives and 6.0% in emergencies) and was associated with ASA physical status IV-V and emergency status.

CONCLUSIONS

Patients presenting for gastrointestinal endoscopy at a group of public university-affiliated hospitals where most sedation is managed by anaesthetists, had a high risk profile and a substantial incidence of significant unplanned intraoperative events and 30-day mortality.

Barriers to the identification of frailty in hospital: a survey of UK clinicians

Despite numerous national campaigns, frailty remains under-recognised in the hospital setting. We performed a survey of hospital-based clinicians across the UK to identify barriers to the identification and best practice management of frailty in hospital. A total of 402 clinicians were surveyed across a range of grades, specialties and hospitals. Responses highlighted variable awareness and personal understanding of frailty, particularly among junior doctors and clinicians in non-medical specialties. Although 74% of responders agreed frailty assessments should be undertaken for all older people admitted to hospital, only 36% felt this was currently feasible with available resources. Free-text responses highlighted limited education, the perceived subjectivity of frailty assessments, scepticism as to their utility in the hospital setting, and deficiencies in service provision. This was the first survey of UK hospital clinicians regarding frailty assessments. Results highlight multiple areas for improvement and engagement.

Embedding comprehensive geriatric assessment in the emergency assessment unit: the impact of the COPE zone

We introduced a geographically embedded frailty unit, the comprehensive older person's evaluation 'COPE' zone within our emergency assessment unit (EAU). We collated data for all medical patients over 75 years admitted non-electively for one month before and after this service change. Significantly more patients were seen by a geriatrician on the EAU earlier in their admission in 2014 (33.4 vs 19.3%, p<0.001; 11 vs 20 h, p<0.001). More patients had documented comprehensive geriatric assessment and discussion in a geriatrician multidisciplinary team meeting (relative risk (RR) 3.3, 95% confidence interval (CI) 2.35-4.73, p<0.001; RR 3.6, 95% CI 2.26-5.57, p<0.001, respectively). More patients with markers of frailty were discharged directly from EAU (42.2 vs 29.0%, p = 0.006) without increasing readmissions. Mean length of stay was reduced (9.5 vs 6.8 days, p = 0.02). The introduction of the COPE zone has improved service delivery at the point of access for older people admitted to hospital.

Risk factors for aspiration in community-acquired pneumonia: analysis of a hospitalized UK cohort

BACKGROUND

There is a move toward finding clinically useful "phenotypes" in community-acquired pneumonia: groups of patients displaying distinct clinical characteristics, microbiology, and prognosis. Aspiration pneumonia is an intuitive clinical phenotype; however, to date there are no recognized diagnostic criteria, and data regarding outcomes in suspected aspiration are limited.

METHODS

An observational study of 1348 patients hospitalized with community-acquired pneumonia in the United Kingdom examined both short- and long-term outcomes for patients at risk of aspiration pneumonia. Patients were defined as "at risk" in the presence of chronic neurologic disorders, esophageal disorders and dysphagia, impaired conscious level, vomiting, or witnessed aspiration. The primary outcome was 30-day mortality. Secondary outcomes included 1-year mortality, readmissions, and recurrent pneumonia within 1 year.

RESULTS

Some 13.8% of the cohort were classified as "at risk of aspiration." These patients were older (median age, 74 years [interquartile range, 60-84] vs 66 years [interquartile range, 49-77]; P < .0001) and more likely to have comorbidities (chronic liver disease 11.3% vs 3.7%, P < .0001; congestive heart failure 28% vs 17.1%, P = .0004; and stroke 26.9% vs 9.5%, P < .0001). Patients at risk of aspiration pneumonia had a poorer short-term outcome (30-day mortality 17.2% vs 7.7%, P < .0001), but after adjusting for their greater severity of illness and comorbidities this difference was not significant (odds ratio 1.05; 95% confidence interval [CI], 0.63-1.76; P = .8). However, patients with aspiration risk factors were at greater risk of poor long-term outcomes with increased 1-year mortality (hazard ratio [HR], 1.73; 95% CI, 1.15-2.58), increased risk of rehospitalization (HR, 1.52; 95% CI, 1.21-1.91), and a strong association with recurrent admissions with pneumonia (HR, 3.13; 95% CI, 2.05-4.78) after multivariable adjustment.

CONCLUSIONS

Using risk factors to identify patients at risk of aspiration pneumonia identifies a distinct clinically useful phenotype of patients with greater severity of disease and poorer long-term outcomes.

Validation of the Infectious Diseases Society of America/American Thoratic Society minor criteria for intensive care unit admission in community-acquired pneumonia patients without major criteria or contraindications to intensive care unit care

BACKGROUND

The 2007 Infectious Disease Society of America/American Thoracic Society (IDSA/ATS) guidelines for community-acquired pneumonia (CAP) recommended new criteria to guide admission to the intensive care unit (ICU) for patients with this condition. Although the major criteria (requirement for mechanical ventilation or septic shock requiring vasopressor support) are well established, the value of the minor criteria alone have not been fully validated.

METHODS

We performed a prospective observational study of consecutive adult patients with CAP admitted to NHS Lothian (Scotland, United Kingdom). Patients meeting the IDSA/ATS major criteria on admission were excluded, along with patients not suitable for ICU care owing to advanced directives or major comorbid illnesses. Performance characteristics for the IDSA/ATS minor criteria were calculated and compared with those for alternative scoring systems identified in the literature. Two definitions of severe CAP were used as primary end points: ICU admission, and subsequent requirement for mechanical ventilation or vasopressor support (MV/VS); 30-day mortality was a secondary outcome.

RESULTS

The study included 1062 patients with CAP potentially eligible for ICU admission. Each of the 9 minor criteria was associated with increased risk of MV/VS and 30-day mortality in univariate analysis. Two hundred seven patients had ≥ 3 minor criteria (19.5%). The IDSA/ATS 2007 criteria had an area under the receiver operating characteristic curve of 0.85 (0.82-0.88) for prediction of MV/VS, 0.85 (0.82-0.88) for prediction of ICU admission, and 0.78 (0.74-0.82) for prediction of 30-day mortality. The IDSA/ATS 2007 criteria were at least equivalent to more established scoring systems for prediction of MV/VS and ICU admission and equivalent to alternative scoring systems for predicting 30-day mortality in this patient population.

CONCLUSIONS

In a population of patients with CAP without contraindications to ICU care, the IDSA/ATS minor criteria predict subsequent requirement for MV/VS, ICU admission, and 30-day mortality.

Phosphorylation of the serine 60 residue within the Cdx2 activation domain mediates its transactivation capacity

BACKGROUND & AIMS

Cdx2 is critical in intestinal proliferation and differentiation. Modulation of Cdx2 function in response to cellular signaling is to be elucidated. We hypothesize that phosphorylation of the Cdx2 activation domain can modulate its function.

METHODS

The Cdx2 activation domain was delineated in transient transfections using different portions of Cdx2 fused to the Gal4-DNA binding domain. In vivo phosphorylation was studied by metabolic labeling with (32)P-orthophosphate. To study a potential phosphorylation site, polyclonal antibodies were generated: CNL was raised against amino acids 54-66 of Cdx2 and P-Cdx2-S60 against the same epitope in which serine 60 was phosphorylated.

RESULTS

A critical region for transactivation resides within amino acids 60-70. Substitution of serine 60 with alanine reduces incorporation of (32)P-orthophosphate substantially. S60-phosphorylation decreases Cdx2 transactivation. Phosphorylation of serine 60 can be inhibited with the mitogen-activated protein kinase inhibitors PD98059 or UO126. P-Cdx2-S60 recognizes phosphorylated serine 60 mainly in proliferative compartment of the intestinal epithelial layer. In contrast, CNL recognizes Cdx2 predominantly in the differentiated compartment.

CONCLUSIONS

The Cdx2 activation domain is phosphorylated at serine 60 via the mitogen-activated protein kinase pathway. S60-phosphorylated and S60-nonphosphorylated Cdx2 have different transcriptional activity, as well as different spatial expression patterns in the intestinal epithelium.

Antisense oligonucleotides as research tools

The use of antisense oligonucleotides as both research tools and therapeutic molecules has emerged as a powerful alternative to small molecule inhibitors. Antisense oligonucleotides are short pieces of chemically modified DNA designed to hybridize to specific mRNA sequences present in the target gene. The oligonucleotide interaction with the targeted mRNA can lead to inhibition in the translation of the protein encoded by the targeted transcript through a variety of reasonably well-characterized mechanisms (1-3).

Induction of endogenous Bcl-xS through the control of Bcl-x pre-mRNA splicing by antisense oligonucleotides

Resistance to apoptosis, which plays an important role in tumors that are refractory to chemotherapy, is regulated by the ratio of antiapoptotic to proapoptotic proteins. By manipulating levels of these proteins, cells can become sensitized to undergo apoptosis in response to chemotherapeutic agents. Alternative splicing of the bcl-x gene gives rise to two proteins with antagonistic functions: Bcl-xL, a well-characterized antiapoptotic protein, and Bcl-xS, a proapoptotic protein. We show here that altering the ratio of Bcl-xL to Bcl-xS in the cell using an antisense oligonucleotide permitted cells to be sensitized to undergo apoptosis in response to ultraviolet B radiation and chemotherapeutic drug treatment. These results demonstrate the ability of a chemically modified oligonucleotide to alter splice site selection in an endogenous gene and illustrate a powerful tool to regulate cell survival.

Inhibition of Bcl-xL expression sensitizes normal human keratinocytes and epithelial cells to apoptotic stimuli

The epidermis is continually exposed to harmful mutagens that have the potential to cause DNA damage. To protect the skin from accumulating mutated cells, keratinocytes have developed a highly regulated mechanism of eliminating damaged cells through apoptosis. Bcl-xL is a well-described cell survival protein that when overexpressed in skin can protect keratinocytes from UV radiation-induced apoptosis. To begin to unravel the complex mechanisms that keratinocytes use to survive, we wanted to characterize the role of endogenous Bcl-xL in protecting cells from death. In this study, we describe the development and characterization of an antisense inhibitor to Bcl-xL. We show that this inhibitor reduces Bcl-xL RNA and protein in a concentration-dependent, sequence-specific manner. Furthermore, treatment of keratinocytes and epithelial cells with this inhibitor sensitizes these cells to UV-B radiation and cisplatinum treatment-induced apoptosis. Thus, these results offer direct evidence that Bcl-xL is critical in the protection of skin and epithelial cells from apoptosis and provide a basis for the role of Bcl-xL in keratinocyte and epithelial cell survival.

Pharmacology of antisense oligonucleotide inhibitors of protein expression

The dramatic increase in recent years of both the amount and rate of accumulation of novel genomic sequence information has generated enormous opportunities for the development of new classes of drugs. For these opportunities to be fully capitalized upon, investigators must choose molecular targets for drug development that are likely to yield attractive therapeutic profiles. This will require rapid and effective determination of gene functions in multiple cellular settings. The development of antisense oligonucleotides as specific inhibitors of gene expression should allow such determination of gene function. In addition, the antisense oligonucleotides themselves will likely prove useful as drugs. In this review, we discuss some of the issues surrounding the use of antisense oligonucleotides as research tools to help elucidate gene function, and highlight some of the approaches that can be taken to generate and use effective antisense reagents.

The role of antiapoptotic Bcl-2 family members in endothelial apoptosis elucidated with antisense oligonucleotides

In this study, we utilized potent antisense oligonucleotides to examine the role of two Bcl-2 family members found in human umbilical vein endothelial cells (HUVEC). The first, A1, is thought to be a TNF-alpha-inducible cytoprotective gene, and the second, Bcl-XL, is constitutively expressed. Inhibition of the constitutive levels of Bcl-XL caused 10-25% of the cell population to undergo apoptosis and increased the susceptibility of cells to treatment with low concentrations of staurosporin or ceramide. The caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp(OMe)-CH2 prevented DNA fragmentation and DeltaYm loss caused by Bcl-XL inhibition or Bcl-XL inhibition combined with staurosporin. However, disruption of DeltaYm caused by Bcl-XL inhibition combined with ceramide treatment was not inhibited by benzyloxycarbonyl-Val-Ala-Asp(OMe)-CH2, although DNA fragmentation was completely prevented. Taken together, these results demonstrate a direct protective role for Bcl-XL under normal resting conditions and under low level apoptotic challenges to HUVEC. Furthermore, Bcl-XL protects cells from caspase-dependent and -independent mechanisms of DeltaYm disruption. In contrast to Bcl-XL, A1 inhibition did not show a marked effect on the susceptibility of HUVEC to undergo apoptosis in response to TNF-alpha, ceramide, or staurosporin. These results demonstrate that although A1 may be a cytoprotective gene induced by TNF-alpha, it is not primarily responsible for HUVEC resistance to this cytokine.

CREB-binding [corrected] protein interacts with the homeodomain protein Cdx2 and enhances transcriptional activity

Cdx2 encodes for a homeodomain protein that is expressed in intestinal epithelial cells. The Cdx2 protein triggers intestinal differentiation in cell lines and is necessary for maintenance of the intestinal phenotype in mice. CBP (cAMP response element-binding protein) is a transcriptional co-activator that interacts with many transcription factors and components of the basal transcriptional machinery. In this study, we demonstrate that CBP is markedly induced upon differentiation of the Caco-2 intestinal cell line and augments Cdx2-dependent transcriptional activity. Cdx2 interacts with the amino-terminal domain of CBP, and the two proteins coexist in vivo within the same nuclear protein complex. Moreover, expression of the CBP domain that interacts with Cdx2 acts as a dominant-negative inhibitor of transcriptional activation by Cdx2. These findings demonstrate a direct interaction between an intestinal homeodomain protein and CBP and suggest that CBP participates in the network of transcriptional proteins that direct intestinal differentiation.

Regulation of pre-mRNA splicing by antisense oligonucleotides

Numerous human diseases arise from mutations that result in aberrant RNA splicing. To date, traditional therapeutic approaches have not been successful in targeting these mutations and restoring correct splicing. Antisense oligonucleotides may provide a novel and effective way to restore correct splicing in mutant genes. Historically, antisense oligonucleotides have been used to decrease mRNA transcripts of disease gene products through an RNase H-dependent mechanism. Through chemical modifications of antisense oligonucleotides, it has been possible to generate compounds that bind to specific mRNA sequences with high affinity, yet do not cause the degradation of the RNA transcript. By directing chemically-modified oligonucleotides to regions of the pre-mRNA important for splicing, it may be possible to inhibit splicing at mutant splice sites. This novel and relatively unexplored application of antisense technology could be of tremendous therapeutic benefit in the treatment of human disease.

Comparison of intestinal phospholipase A/lysophospholipase and sucrase-isomaltase genes suggest a common structure for enterocyte-specific promoters

Intestinal phospholipase A/lysophospholipase (IPAL) is an intestine-specific brush-border enzyme expressed during development and along the intestinal crypt-villus axis in a pattern similar to another well characterized brush-border enzyme, sucrase-isomaltase (SI). A tissue-specific DNase I hypersensitive site was identified in chromatin from intestinal nuclei immediately upstream from the transcriptional start site of the IPAL gene. Footprinting analysis showed that two DNA elements within the IPAL promoter were protected by intestinal nuclear proteins. The IPAL-FP1 element was shown to be a monomer binding site for Cdx1 and Cdx2, intestine-specific homeobox proteins. Moreover, this site was important for transcriptional activation of the promoter in intestinal cell lines via interaction with Cdx proteins. Nuclear proteins from both liver and intestine interacted with the IPAL-FP2 element, forming a complex consistent with binding to HNF1. Cdx and HNF1 binding sites have also been shown to be the two major regulatory elements responsible for transcriptional activation of the SI gene promoter, which directs intestine-specific transcription in transgenic mice. These findings suggest that enterocyte genes that are expressed in similar developmental patterns may be regulated by the interaction of common DNA elements and their associated transcription factors.

CDX1 protein expression in normal, metaplastic, and neoplastic human alimentary tract epithelium

BACKGROUND & AIMS

CDX1 is an intestine-specific transcription factor expressed early in intestinal development that may be involved in regulation of proliferation and differentiation of intestinal epithelial cells. We examined the pattern of CDX1 protein expression in metaplastic and neoplastic tissue to provide insight into its possible role in abnormal differentiation.

METHODS

Tissue samples were stained by immunohistochemistry using an affinity-purified, polyclonal antibody against a peptide epitope of CDX1.

RESULTS

Specific nuclear staining was found in epithelial cells of the small intestine and colon. Esophagus and stomach did not express CDX1 protein; however, adjacent areas of intestinal metaplastic tissue intensely stained for CDX1. Adenocarcinomas of the stomach and esophagus had both positive and negative nuclear staining for CDX1. Colonic epithelial cells in adenomatous polyps and adenocarcinomas had a decreased intensity of staining compared with normal colonic crypts in the same specimen.

CONCLUSIONS

CDX1 may be important in the transition from normal gastric and esophageal epithelium to intestinal-type metaplasia. The variability in expression of CDX1 in gastric and esophageal adenocarcinomas suggests more than one pathway in the development of these carcinomas. The decrease of CDX1 in colonic adenocarcinomas may indicate a role for CDX1 in growth regulation and in the maintenance of the differentiated phenotype.

Coronal leakage: effects of smear layer, obturation technique, and sealer

Coronal microleakage may be a major factor in the etiology of treatment failure. This study examined the effect of obturation technique, sealer, and the presence of smear layer on coronal microleakage. Two hundred extracted human teeth were assigned to 20 treatment groups. Groups were examined with the smear layer present or smear layer removed (17% REDTA). Access cavities were exposed to artificial saliva then Pelikan Ink. Teeth were cleared and linear dye penetration measured. When all groups with the smear layer removed were compared with all groups with the smear layer present, significantly less leakage was seen when the smear layer was removed. Ultrafil displayed significantly more leakage than all other groups. Vertical compaction of lateral condensation and Thermafil obturations significantly reduced leakage. AH-26 displayed significantly less leakage than Roth's 811 sealer. These results indicate that removal of the smear layer, the use of AH-26, and vertical compactin have cumulative effects in reducing coronal leakage.

Activation of enhancer elements by the homeobox gene Cdx2 is cell line specific

Cdx2 is a caudal-related homeodomain transcription factor that is expressed in complex patterns during mouse development and at high levels in the intestinal epithelium of adult mice. Cdx2 activates transcription of intestinal gene promoters containing specific binding sites. Moreover, Cdx2 has been shown to induce intestinal differentiation in cell lines. In this study, we show that Cdx2 is able to bind to two well defined enhancer elements in the HoxC8 gene. We then demonstrate that Cdx2 is able to activate transcription of heterologous promoters when its DNA binding element is placed in an enhancer context. Furthermore, the ability to activate enhancer elements is cell-line dependent. When the Cdx2 activation domain was linked to the Gal4 DNA binding domain, the chimeric protein was able to activate Gal4 enhancer constructs in an intestinal cell line, but was unable to activate transcription in NIH3T3 cells. These data suggest that there are cell-specific factors that allow the Cdx2 activation domain to function in the activation of enhancer elements. We hypothesize that either a co-activator protein or differential phosphorylation of the activation domain may be the mechanism for intestinal cell line-specific function of Cdx2 and possibly in other tissues in early development.

Radiographic and histologic periapical findings of root canal treated teeth in cadaver

The success of root canal treatment can be subjectively evaluated both clinically and radiographically. Normally, the recall radiograph is the main factor in evaluating success or failure.

OBJECTIVES

This study evaluated periapical areas of root canal treated teeth by correlating radiographic and histologic findings.

STUDY DESIGN

Jaws were resected from cadavers and radiographed. Those teeth that had received root canal treatment were evaluated for success or failure based on radiographic criteria. Teeth and surrounding bone were then removed en bloc and prepared for light microscopy. Untreated teeth without periapical pathosis were examined as controls.

RESULTS

Root canal treated teeth classified as failures were found to consistently have inflammatory resorptive lesions at the periapices. In contrast, those treated teeth classified as radiographically successful showed varying reactions ranging from normal uninflamed to mildly inflamed.

CONCLUSIONS

Those classified as failure showed consistent inflammation. However, the majority of our examined treated teeth were radiographically normal and exhibited no periapical inflammation.

Corrosion at the interface. A possible solution to cobalt-chrome heads on titanium alloy stems

The low-wear characteristics of cobalt-chrome femoral heads matched with the excellent biocompatibility and low modulus of titanium alloy femoral stems constitute the preferred combination used by many orthopaedic surgeons performing total hip arthroplasty. The combination of these materials in a synovial fluid environment, however, has proven to result in extensive crevice corrosion and metallosis of the surrounding tissues. This study investigates an alternative to the conventional mating of dissimilar metals at the head-neck junction. Five cobalt-chrome heads premated with titanium alloy sleeves were investigated by gross examination, dissecting microscopy, and scanning electron microscopy. Examination by both gross examination and dissecting microscope revealed no signs of corrosion. Scanning electron microscope examination revealed slight crevice corrosion in the only head with a +15-mm neck length.

Use of acetabular models in planning complex acetabular reconstructions

The number of patients requiring revision total hip arthroplasty continues to increase each year. Accurate preoperative planning is a key factor in obtaining a good result. Radiographs provide little information concerning the actual extent of the acetabular defects. Computed tomography-generated models of the acetabulum can provide the surgeon with accurate information concerning the size and location of the defects. Evaluation of radiographs and models in 24 cases showed that radiographs alone failed to detect all 13 anterior wall defects (P < .001), 8 of 18 posterior wall defects (44.4%, P < .001), and 8 of 19 segmental central defects (42%, P < .001), all of which were easily identified with the models. This study showed that preoperative planning based on the foam models accurately predicted the actual implant used in 22 of 24 cases (92%).

Comparison of glucocorticoid-induced effects in prolactin-dependent and autonomous rat Nb2 lymphoma cells

Cultured Nb2 node rat lymphoma cells require lactogenic hormone for their proliferation. We reported previously that dexamethasone (Dex) inhibits prolactin (PRL)-induced mitogenesis and, in the absence of mitogen, induces apoptosis of Nb2 cells. Both antiproliferative and cytolytic effects of Dex on Nb2 cells appear to involve glucocorticoid (Type II) receptor mediation. In this study, we compared Dex effects in PRL-dependent Nb2 cells (Nb2) with SFJCD1 (SF), a clone of Nb2 cells that proliferates independently of exogenous PRL. Proliferative assays involved a 72-hr incubation in a chemically defined, serum-free medium where ovine PRL (1 ng/ml) was added to Nb2 cells but not to SF cells. Both cell lines were responsive to the antiproliferative effects of Dex in a dose (6.25-200 nM)-dependent fashion of comparable sensitivity and magnitude. Co-incubation with the glucocorticoid receptor antagonist, RU 486, prevented the antiproliferative effect of Dex in both cell lines. In the same medium devoid of PRL, Dex was cytolytic to Nb2 cells and fragmented DNA in a fashion reflective of apoptosis, but was ineffective in SF cells. A dual chamber incubation system revealed no evidence that SF cells produced cytokines that were mitogenic or anticytolytic to Nb2 cells. Both Nb2 and SF cells fragmented DNA in a fashion indicative of apoptosis in the presence of the Ca2+ ionophore, A23187 (1 microM). These studies reveal a basic difference in glucocorticoid responsiveness between the PRL-dependent Nb2 cell line and its PRL-independent subclone, SF. While both cell lines exhibit functional glucocorticoid receptors and the necessary intranuclear machinery for apoptosis, the pathway mediating the latter is inhibited or dysfunctional in SF cells.

Management of bone loss in revision total hip arthroplasty using custom cementless femoral components

Forty-seven consecutive revision total hip arthroplasties were performed using porous ingrowth custom-made prostheses designed from plain radiographs and computed tomography scans. At an average follow-up period of 30 months (range, 2-4 years), one revision has been required for loosening. The average Harris pain score was 39 and the average total score was 84 at the last follow-up evaluation. Complications included nine cases (19%) with intraoperatively detected fractures of the proximal femur treated with cerclage wires and seven cases (15%) with subsidence greater than 3 mm. There were no postoperative infections and only two dislocations. At the time of surgery local particulate bone graft was used in all cases. Thirty-four percent required structural graft to restore bone stock; no case required grafting for prosthesis stability. Management of bone loss in total hip arthroplasty using a custom cementless prosthesis appears to provide an attractive alternative to massive bone grafting.

Kinetics of germinal center development in lymph nodes of young and aging immune mice

Recent findings imply that germinal center paucity in old mice, at least in part, results from a defect in the mechanisms responsible for the transport of antigens to lymphoid nodules (follicles) and the consequent impairment of the antigen retaining reticulum (ARR) of follicular dendritic cells (FDCs). The present objective was to observe the kinetics of lymph node germinal center development in old mice having antigen transport and ARR deficits. Germinal center development was monitored in popliteal (PLN) and axillary (AXLN) lymph nodes of 6-8 wk and 23-mo-old horseradish peroxidase (HRP) immune C57BL/6 mice. Using the selective binding of germinal center B cells for peanut agglutinin (PNA), germinal centers were identified in serial vibratome sections following histochemical labeling with PNA-peroxidase conjugates at times 0, 15 min, 1, 3, 5, and 10 days after footpad challenge with 8 micrograms HRP. To follow the fate of preexisting (environmental antigen-induced) germinal centers and the development of de novo (HRP-induced) germinal centers, it was essential to distinguish between these germinal centers. Accordingly, PNA positive germinal centers associated with HRP-retaining (peroxidase positive) ARR were identified as de novo germinal centers and germinal centers not associated with a peroxidase positive ARR were classified as preexisting germinal centers. Kinetic analysis of PNA positive germinal centers showed the following: 1) Preexisting, environmentally-induced germinal centers dissociated and disappeared by day 3 as indicated by a decline in their numbers after antigen injection: the process of germinal center dissociation remained unaffected by aging. 2) The latency of de novo germinal center appearance was approximately equal in duration (approximately 3 days) to the disappearance of pre-existing germinal centers. 3) The number and size of de novo HRP-induced germinal centers increased through the experimental period in young lymph nodes, but in old mice these parameters were depressed, resulting in a significant germinal center deficit. 4) The ratio of HRP-retaining ARR to de novo induced germinal centers was 1:1 in young and responder old mice. This ratio was not affected by aging. This finding favored the concept that antigen retention in ARR is a requirement of germinal center development. The observations supported our hypothesis that germinal center development, at least in part, depends on a normal antigen transport by showing that in aged mice with defective antigen transport-related ARR and iccosome deficits there is an impaired development of germinal centers.

Simulation: an evolving methodology for health administration education

Simulation provides a valuable addition to a university's teaching methods. Computer-assisted gaming is especially effective in teaching advanced business strategy and corporate policy when the nature and complexity of the simulation permit. The potential for using simulation techniques in postgraduate professional education and in managerial self-assessment appears to be significant over the next several years.

Improving productivity in the x-ray film file room

A film filing system using color coding of the last two digits of assigned numbers was compared with a system designed around the current film file and readily available patient identifiers: name, sex, and date of examination. In the FASD system (filed alphabetically by sex and date), films are filed in time units by date of last activity and within these time units by sex and last name. The FASD system was shown to cut in half the routine work of film filing.

Results of spinal cord stimulation in multiple sclerosis

The results of spinal cord stimulation by various methods in 204 patients with multiple sclerosis are presented.

A calibration system for producing known concentrations of mercury vapor in air

This paper describes the construction and evaluation of a system capable of producing well-defined test mixtures of mercury in air, or other diluent gas, at mercury concentrations between zero and 16 mg/M3. The various parameters that affect the generation system and their interactions are discussed and data is given for the calibration of several different mercury monitors.