Interhospital variability in cardiac rehabilitation use after cardiac surgery among Medicare beneficiaries

OBJECTIVE

Despite guideline recommendation, cardiac rehabilitation (CR) after cardiac surgery remains underused, and the extent of interhospital variability is not well understood. This study evaluated determinants of interhospital variability in CR use and outcomes.

METHODS

This retrospective cohort study included 166,809 Medicare beneficiaries undergoing cardiac surgery who were discharged alive between July 1, 2016, and December 31, 2018. CR participation was identified in outpatient facility claims within a year of discharge. Hospital-level CR rates were tabulated, and multilevel models evaluated the extent to which patient, organizational, and regional factors accounted for interhospital variability. Adjusted 1-year mortality and readmission rates were also calculated for each hospital quartile of CR use.

RESULTS

Overall, 90,171 (54.1%) participated in at least 1 CR session within a year of discharge. Interhospital CR rates ranged from 0.0% to 96.8%. Hospital factors that predicted CR use included nonteaching status and lower-hospital volume. Before adjustment for patient, organizational, and regional factors, 19.3% of interhospital variability was attributable to the admitting hospital. After accounting for covariates, 12.3% of variation was attributable to the admitting hospital. Patient (0.5%), structural (2.8%), and regional (3.7%) factors accounted for the remaining explained variation. Hospitals in the lowest quartile of CR use had greater adjusted 1-year mortality rates (Q1 = 6.7%, Q4 = 5.2%, P < .001) and readmission rates (Q1 = 37.6%, Q4 = 33.9%, P < .001).

CONCLUSIONS

Identifying best practices among high CR use facilities and barriers to access in low CR use hospitals may reduce interhospital variability in CR use and advance national improvement efforts.

The relationship between discharge location and cardiac rehabilitation use after cardiac surgery

BACKGROUND

Cardiac rehabilitation (CR) is a guideline-recommended risk-reduction program offered to cardiac surgical patients. Despite CR's association with better outcomes, attendance remains poor. The relationship between discharge location and CR use is poorly understood.

METHODS

This study was a nationwide, retrospective cohort analysis of Medicare fee-for-service claims for beneficiaries undergoing coronary artery bypass grafting and/or surgical aortic valve repair between July 1, 2016, and December 31, 2018. The primary outcome was attendance of any CR session. Discharge location was categorized as home discharge or discharge to extended care facility (ECF) (including skilled nursing facility, inpatient rehabilitation, and long-term acute care). Multivariable logistic regression models evaluated the association between discharge location, CR attendance, and 1-year mortality.

RESULTS

Of the 167,966 patients who met inclusion criteria, 34.1% discharged to an ECF. Overall CR usage rate was 53.9%. Unadjusted and adjusted CR use was lower among patients discharged ECFs versus those discharged home (42.1% vs 60.0%; adjusted odds ratio, 0.66; P < .001). Patients discharged to long-term acute care were less likely to use CR than those discharged to skilled nursing facility or inpatient rehabilitation (reference category: home; adjusted odds ratio for long-term acute care, 0.36, adjusted odds ratio for skilled nursing facility, 0.69, and adjusted odds ratio for inpatient rehabilitation, 0.71; P < .001). CR attendance was associated with a greater reduction in adjusted 1-year mortality in patients discharged to ECFs (9.7% reduction) versus those discharged home (4.3% reduction).

CONCLUSIONS

In this national analysis of Medicare beneficiaries, discharge to ECF was associated with lower CR use, despite a greater association with improved 1-year mortality. Interventions aimed at increasing CR enrollment at ECFs may improve CR use and advance surgical quality.

Biofilm-derived oxylipin 10-HOME mediated immune response in women with breast implants

Breast implant illness (BII) is a poorly understood disease in which patients develop symptoms typical of autoimmune conditions following breast implantation. There is no known underlying cause, and patients often resort to breast implant removal and capsulectomy to alleviate symptoms. In this issue of the JCI, Khan and colleagues examined 86 breast explants from patients that reported BII symptoms and 55 control explants. The BII group showed a disproportionally high degree of biofilm, which was associated with oxylipin (10-HOME) on the implant surfaces. Injections of 10-HOME in the mammary fat pad of a murine model recapitulated BII symptoms and increased Th1 cell populations. Notably, macrophages in the periprosthetic tissue from BII patients were more likely to exhibit a proinflammatory phenotype, and naive T cells exposed to 10-HOME caused naive macrophages to differentiate to a proinflammatory phenotype. This work provides a pathophysiologic mechanism for a currently understudied and poorly characterized disease.

Interhospital variability in failure to rescue rates following aortic valve surgery

Objective

This study evaluated interhospital variability and determinants of failure-to-rescue for patients undergoing surgical aortic valve replacement.

Methods

An observational study was conducted among 28,842 patients undergoing aortic valve replacement with or without coronary artery bypass grafting between July 2011 and June 2017 across 90 hospitals participating in the Society of Thoracic Surgeons Adult Cardiac Surgery Database. Postoperative complications were defined as major (stroke, renal failure, reoperation, prolonged ventilation, sternal infection) and overall (major plus 14 other morbidities). Hospital terciles of observed to expected (O/E) mortality were compared on crude rates of major and overall complications, operative mortality, and failure to rescue (among major and overall complications). The correlation between hospital observed and expected failure-to-rescue rates was assessed.

Results

Median Society of Thoracic Surgeons Adult Cardiac Surgery Database predicted mortality risk was similar across hospital O:E mortality terciles (P = .10). As expected, mortality rates significantly increased across terciles (low O/E tercile: 1.6%, high O/E tercile: 4.7%; P < .001). Failure-to-rescue rates increased substantially across hospital mortality terciles among patients with major (low tercile, 8.8% and high tercile, 20.8%) and overall (low tercile, 3.0% and high tercile, 8.9%) complications. Hospital-level expected failure to rescue had a higher correlation with observed complications for overall complications (R2 = 0.71) compared with Society of Thoracic Surgeons major complications (R2 = 0.24).

Conclusions

Considerable interhospital variation exists in failure-to-rescue rates following aortic valve replacement. Hospitals in the low O/E mortality tercile experience failure to rescue nearly one-third less than those in the high O/E mortality tercile. Efforts to advance quality will benefit from identifying and disseminating optimal rescue strategies in this patient population.

Cardiac Rehabilitation Reduces 2-Year Mortality After Coronary Artery Bypass Grafting

BACKGROUND

Cardiac rehabilitation (CR) is a supervised outpatient exercise and risk reduction program offered to patients who have undergone coronary revascularization procedures. Multiple professional societal guidelines support the use of CR after coronary artery bypass grafting (CABG) based on studies in combined percutaneous coronary intervention and CABG populations with surrogate outcomes. This statewide analysis of patients undergoing CABG evaluated the relationship between CR use and long-term mortality.

METHODS

Medicare fee-for-service claims were linked to surgical data for patients discharged alive after isolated CABG from January 1, 2015, through September 30, 2019. Outpatient facility claims were used to identify any CR use within 1 year of discharge. Death within 2 years of discharge was the primary outcome. Mixed-effects logistic regression was used to predict CR use, adjusting for a variety of comorbidities. Unadjusted and inverse probability treatment weighting (IPTW) were used to compare 2-year mortality among CR users vs nonusers.

RESULTS

A total of 3848 of 6412 patients (60.0%) were enrolled in CR for an average of 23.2 (SD, 12.0) sessions, with 770 of 6412 (12.0%) completing all recommended 36 sessions. Logistic regression identified increasing age, discharge to home (vs extended care facility), and shorter length of stay as predictors of postdischarge CR use (P < .05). Unadjusted and IPTW analyses showed significant reduction in 2-year mortality in CR users compared with CR nonusers (unadjusted: 9.4% reduction; 95% CI, 10.8%-7.9%; P < .001; IPTW: -4.8% reduction; 95% CI, 6.0%-3.5%; P < .001).

CONCLUSIONS

These data suggest that CR use is associated with lower 2-year mortality. Future quality initiatives should consider identifying and addressing root causes of poor CR enrollment and completion.

Macrophage-specific inhibition of the histone demethylase JMJD3 decreases STING and pathologic inflammation in diabetic wound repair

Macrophage plasticity is critical for normal tissue repair following injury. In pathologic states such as diabetes, macrophage plasticity is impaired, and macrophages remain in a persistent proinflammatory state; however, the reasons for this are unknown. Here, using single-cell RNA sequencing of human diabetic wounds, we identified increased JMJD3 in diabetic wound macrophages, resulting in increased inflammatory gene expression. Mechanistically, we report that in wound healing, JMJD3 directs early macrophage-mediated inflammation via JAK1,3/STAT3 signaling. However, in the diabetic state, we found that IL-6, a cytokine increased in diabetic wound tissue at later time points post-injury, regulates JMJD3 expression in diabetic wound macrophages via the JAK1,3/STAT3 pathway and that this late increase in JMJD3 induces NFκB-mediated inflammatory gene transcription in wound macrophages via an H3K27me3 mechanism. Interestingly, RNA sequencing of wound macrophages isolated from mice with JMJD3-deficient myeloid cells (Jmjd3f/fLyz2Cre+) identified that the STING gene (Tmem173) is regulated by JMJD3 in wound macrophages. STING limits inflammatory cytokine production by wound macrophages during healing. However, in diabetic mice, its role changes to limit wound repair and enhance inflammation. This finding is important since STING is associated with chronic inflammation, and we found STING to be elevated in human and murine diabetic wound macrophages at late time points. Finally, we demonstrate that macrophage-specific, nanoparticle inhibition of JMJD3 in diabetic wounds significantly improves diabetic wound repair by decreasing inflammatory cytokines and STING. Taken together, this work highlights the central role of JMJD3 in tissue repair and identifies cell-specific targeting as a viable therapeutic strategy for nonhealing diabetic wounds.

Assessing donor-recipient size metrics for heart transplant outcomes: UNOS database analysis

STUDY

There is no widely accepted donor to recipient size-match metric to predict outcomes in cardiac transplant. The predictive ability of size-match metrics has not been studied when recipients are stratified by heart failure etiology. We sought to assess the performance of commonly used size metrics to predict survival after heart transplant, accounting for restrictive vs. non-restrictive pathology.

METHODS

The UNOS registry was queried from 2000-2017 for all primary isolated heart transplants. Donor-recipient ratios were calculated for commonly used size metrics and their association with survival was assessed using continuous, nonlinear analysis.

RESULTS

29,817 patients were identified. Height (p<0.001), predicted heart mass (PHM) (p = 0.003), ideal body weight (IBW) (p<0.001) and body mass index (BMI) (p = 0.003) ratios were significantly associated with survival, while weight and body surface area (BSA) ratios were not. When stratified, only BMI ratio retained significance for both restrictive (p = 0.051) and non-restrictive (p = 0.003) subsets. Recipients with restrictive etiology had increased risk of mortality with both a lower and higher BMI ratio.

CONCLUSIONS

While many metrics show association with survival in the non-restrictive subset, BMI is the only metric that retains significance in the restrictive subset. Recipients with restrictive and non-restrictive etiologies of heart failure tolerate size mismatch differently. This article is protected by copyright. All rights reserved.

First-in-human phase 1 study of the anti-TIGIT antibody vibostolimab as monotherapy or with pembrolizumab for advanced solid tumors, including non-small cell lung cancer

BACKGROUND

In this first-in-human phase 1 study, we investigated the safety and efficacy of the anti-TIGIT antibody vibostolimab as monotherapy or in combination with pembrolizumab.

METHODS

Part A enrolled patients with advanced solid tumors and part B enrolled patients with non-small cell lung cancer (NSCLC). Patients received vibostolimab 2.1-700 mg alone or with pembrolizumab 200 mg in part A and vibostolimab 200 mg alone or with pembrolizumab 200 mg in part B. Primary end points were safety and tolerability. Secondary end points included pharmacokinetics and objective response rate (ORR) per RECIST v1.1.

RESULTS

Part A enrolled 76 patients (monotherapy, 34; combination therapy, 42). No dose-limiting toxicities were reported. Across doses, 56% of patients receiving monotherapy and 62% receiving combination therapy had treatment-related adverse events (TRAEs); grade 3-4 TRAEs occurred in 9% and 17% of patients, respectively. The most common TRAEs were fatigue (15%) and pruritus (15%) with monotherapy and pruritus (17%) and rash (14%) with combination therapy. Confirmed ORR was 0% with monotherapy and 7% with combination therapy. In part B, 39 patients had anti-PD-1/PD-L1-naïve NSCLC (all received combination therapy) and 67 had anti-PD-1/PD-L1-refractory NSCLC (monotherapy, 34; combination therapy, 33). In patients with anti-PD-1/PD-L1-naive NSCLC: 85% had TRAEs-the most common were pruritus (38%) and hypoalbuminemia (31%); confirmed ORR was 26%, with responses occurring in both PD-L1-positive and PD-L1-negative tumors. In patients with anti-PD-1/PD-L1‒refractory NSCLC: 56% receiving monotherapy and 70% receiving combination therapy had TRAEs-the most common were rash and fatigue (21% each) with monotherapy and pruritus (36%) and fatigue (24%) with combination therapy; confirmed ORR was 3% with monotherapy and 3% with combination therapy.

CONCLUSION

Vibostolimab plus pembrolizumab was well tolerated and demonstrated antitumor activity in patients with advanced solid tumors, including patients with advanced NSCLC.

Development of malignancies and their outcomes in patients supported on continuous-flow left ventricular assist devices-a systematic review

Background

With increased use of continuous-flow left ventricular assist devices (CF-LVAD), development of malignant tumors in this population is not uncommon. We sought to evaluate malignancies in CF-LVAD patients and evaluate the outcomes of treatment strategies.

Methods

Overall, 18 articles consisting of 28 patients were identified who developed malignancies after CF-LVAD placement. Patient-level data were extracted for systematic review.

Results

Median patient age was 60 years [59-67] and 85.7% (24/28) were male. CF-LVAD was placed as bridge-to-transplant (BTT) in 60.9% (14/23) of patients. The three most common malignancy types were GI in 35.7% (10/28) of patients, lung in 21.4% (6/28) and skin in 10.7% (3/28). Median time from CF-LVAD implant to malignancy diagnosis was 6.9 [2.5-12.8] months. Metastatic disease occurred in 17.9% (5/28) over a median time of 5.0 [1.0-82.0] months from the diagnosis. Surgical resection of the malignancy was performed in 57.1% (16/28) of patients. Our results showed that while there was a significantly higher probability of survival among patients who underwent surgery versus those who did not, when only stage I and II patients were included in the analysis, this difference was no longer statistically significant. Three patients were relisted for heart transplant after surgical treatment, and two received the transplant.

Conclusions

Surgical management of malignancies in patients on CF-LVADs may improve survival and transplant eligibility status, therefore, a CF-LVAD should not always preclude surgical treatment.

Bernard J. Miller: MD, ScD. (Hon), FACS: Lifelong Surgeon-Scientist and Critical Contributor to the Gibbon Heart-Lung Machine

Bernard J. Miller, MD, ScD. (Hon), FACS, is known as a critical contributor for his work in the John H. Gibbon, MD, laboratory for his work on the heart-lung machine (HLM). In this setting, Dr. Miller developed the fluid control servo system, which was necessary to prevent malfunctioning of the HLM and prevent air emboli. Additionally, Dr. Miller assisted in conceiving and testing the left ventricular vent, the positive-negative pressure ventilator, and the HLM oxygenator; these inventions were all the product of extensive collaboration between the International Business Machines Corporation and the members of Dr. Gibbon's laboratory. Furthermore, Dr. Miller was a surgical assistant and perfusionist in the first successful open-heart surgery. Herein, we seek to describe Dr. Miller's story and his contributions to the HLM, as well as the contributions that were developed by the laboratory at that time. Additionally, we describe critical events leading up to the first successful use of the HLM on May 6, 1953, including a previously unreported use of the HLM for partial bypass of the right heart at Pennsylvania Hospital in 1952. Finally, we present the rest of Dr. Miller's professional and personal successes after his work on the HLM ended.

Intracranial and extracranial efficacy of lorlatinib in patients with ALK-positive non-small-cell lung cancer previously treated with second-generation ALK TKIs

BACKGROUND

Lorlatinib, a potent, brain-penetrant, third-generation anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor (TKI), has substantial activity against ALK-positive non-small-cell lung cancer (NSCLC). This study assessed the overall, intracranial, and extracranial efficacy of lorlatinib in ALK-positive NSCLC that progressed on second-generation ALK TKIs.

PATIENTS AND METHODS

In the ongoing phase II study (NCT01970865), patients with ALK-positive advanced NSCLC treated with ≥1 prior second-generation ALK TKI ± chemotherapy were enrolled in expansion cohorts (EXP) based on treatment history. Overall, intracranial and extracranial antitumor activity were assessed independently per modified Response Evaluation Criteria in Solid Tumors (RECIST) v1.1.

RESULTS

Of the 139 patients with ≥1 prior second-generation ALK TKI (EXP3B-5), 28 received one prior second-generation ALK TKI (EXP3B), 65 two prior ALK TKIs (EXP4), and 46 three prior ALK TKIs (EXP5). In EXP3B-5, the objective response rate (ORR) [95% confidence intervals] was 39.6% (31.4-48.2), intracranial ORR (IC-ORR) was 56.1% (42.4-69.3), extracranial ORR (EC-ORR) was 36.7% (28.7-45.3), median duration of response (DOR) was 9.6 months [5.6-16.7; IC-DOR, 12.4 (6.0-37.1); EC-DOR, 9.7 (6.1-33.3)], median progression-free survival was 6.6 (5.4-7.4) months, and median overall survival was 20.7 months (16.1-30.3). In EXP3B, the ORR was 42.9% (24.5-62.8), the IC-ORR was 66.7% (29.9-92.5), and the EC-ORR was 32.1% (15.9-52.4). In EXP4 and EXP5, the ORR was 38.7% (29.6-48.5), the IC-ORR was 54.2% (39.2-68.6), and the EC-ORR was 37.8% (28.8-47.5).

CONCLUSIONS

Lorlatinib had clinically meaningful intracranial and extracranial antitumor activity in the post-second-generation ALK TKI setting, with elevated intracranial versus extracranial ORR, particularly in patients with fewer lines of therapy.

The Pathway to Low Outlier Status in Venous Thromboembolism Events: An Analysis of Pancreatic Surgery in the National Surgical Quality Improvement Program

Purpose: Our institution's hepatopancreaticobiliary surgery service (HPBS) has demonstrated low rates of venous thromboembolism (VTE). We sought to determine whether the HPBS's regimented multimodal VTE prophylaxis pathway, which includes the use of mechanical prophylaxis, pharmacological prophylaxis, and ambulation, plays a role in achieving low VTE rates.

Methods: We compared pancreatic surgeries in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) participant user file with our institution's data from 2011 to 2016 using univariate, multivariate, and matching statistics.

Results: Among 36,435 NSQIP operations, 850 (2.3%) underwent surgery by the HPBS. The HPBS achieved lower VTE rates than the national cohort (2.0% vs. 3.5%, p = 0.018). Upon multivariate analysis, having an operation performed by the HPBS independently conferred lower odds of VTE incidence in the matched cohort (odds ratio = 0.530, p = 0.041).

Conclusions: We identified an independent correlation between the HPBS and decreased VTE incidence, which we believe to be due to strict adherence to and team participation in a high risk VTE prophylaxis pathway, including inpatient pharmacological prophylaxis, thromboembolic deterrent stockings, sequential compression devices, and mandatory ambulation.

Molecular correlates of response to capmatinib in advanced non-small-cell lung cancer: clinical and biomarker results from a phase I trial

BACKGROUND

Dysregulation of receptor tyrosine kinase MET by various mechanisms occurs in 3%-4% of non-small-cell lung cancer (NSCLC) and is associated with unfavorable prognosis. While MET is a validated drug target in lung cancer, the best biomarker strategy for the enrichment of a susceptible patient population still remains to be defined. Towards this end we analyze here primary data from a phase I dose expansion study of the MET inhibitor capmatinib in patients with advanced MET-dysregulated NSCLC.

PATIENTS AND METHODS

Eligible patients [≥18 years; Eastern Cooperative Oncology Group (ECOG) performance status ≤2] with MET-dysregulated advanced NSCLC, defined as either (i) MET status by immunohistochemistry (MET IHC) 2+ or 3+ or H-score ≥150, or MET/centromere ratio ≥2.0 or gene copy number (GCN) ≥5, or (ii) epidermal growth factor receptor wild-type (EGFRwt) and centrally assessed MET IHC 3+, received capmatinib at the recommended dose of 400 mg (tablets) or 600 mg (capsules) b.i.d. The primary objective was to determine safety and tolerability; the key secondary objective was to explore antitumor activity. The exploratory end point was the correlation of clinical activity with different biomarker formats.

RESULTS

Of 55 patients with advanced MET-dysregulated NSCLC, 40/55 (73%) had received two or more prior systemic therapies. All patients discontinued treatment, primarily due to disease progression (69.1%). The median treatment duration was 10.4 weeks. The overall response rate per RECIST was 20% (95% confidence interval, 10.4-33.0). In patients with MET GCN ≥6 (n = 15), the overall response rate by both the investigator and central assessments was 47%. The median progression-free survival per investigator for patients with MET GCN ≥6 was 9.3 months (95% confidence interval, 3.8-11.9). Tumor responses were observed in all four patients with METex14. The most common toxicities were nausea (42%), peripheral edema (33%), and vomiting (31%).

CONCLUSIONS

MET GCN ≥6 and/or METex14 are suited to predict clinical activity of capmatinib in patients with NSCLC (NCT01324479).

Global knockout of ROMK potassium channel worsens cardiac ischemia-reperfusion injury but cardiomyocyte-specific knockout does not: Implications for the identity of mitoKATP

The renal-outer-medullary‑potassium (ROMK) channel, mutated in Bartter's syndrome, regulates ion exchange in kidney, but its extra-renal functions remain unknown. Additionally, ROMK was postulated to be the pore-forming subunit of the mitochondrial ATP-sensitive K+ channel (mitoKATP), a mediator of cardioprotection. Using global and cardiomyocyte-specific knockout mice (ROMK-GKO and ROMK-CKO respectively), we characterize the effects of ROMK knockout on mitochondrial ion handling, the response to pharmacological KATP channel modulators, and ischemia/reperfusion (I/R) injury. Mitochondria from ROMK-GKO hearts exhibited a lower threshold for Ca2+-triggered permeability transition pore (mPTP) opening but normal matrix volume changes during oxidative phosphorylation. Isolated perfused ROMK-GKO hearts exhibited impaired functional recovery and increased infarct size when I/R was preceded by an ischemic preconditioning (IPC) protocol. Because ROMK-GKO mice exhibited severe renal defects and cardiac remodeling, we further characterized ROMK-CKO hearts to avoid confounding systemic effects. Mitochondria from ROMK-CKO hearts had unchanged matrix volume responses during oxidative phosphorylation and still swelled upon addition of a mitoKATP opener, but exhibited a lower threshold for mPTP opening, similar to GKO mitochondria. Nevertheless, I/R induced damage was not exacerbated in ROMK-CKO hearts, either ex vivo or in vivo. Lastly, we examined the response of ROMK-CKO hearts to ex vivo I/R injury with or without IPC and found that IPC still protected these hearts, suggesting that cardiomyocyte ROMK does not participate significantly in the cardioprotective pathway elicited by IPC. Collectively, our findings from these novel strains of mice suggest that cardiomyocyte ROMK is not a central mediator of mitoKATP function, although it can affect mPTP activation threshold.

Role of Mitochondrial Calcium and the Permeability Transition Pore in Regulating Cell Death

Adult cardiomyocytes are postmitotic cells that undergo very limited cell division. Thus, cardiomyocyte death as occurs during myocardial infarction has very detrimental consequences for the heart. Mitochondria have emerged as an important regulator of cardiovascular health and disease. Mitochondria are well established as bioenergetic hubs for generating ATP but have also been shown to regulate cell death pathways. Indeed many of the same signals used to regulate metabolism and ATP production, such as calcium and reactive oxygen species, are also key regulators of mitochondrial cell death pathways. It is widely hypothesized that an increase in calcium and reactive oxygen species activate a large conductance channel in the inner mitochondrial membrane known as the PTP (permeability transition pore) and that opening of this pore leads to necroptosis, a regulated form of necrotic cell death. Strategies to reduce PTP opening either by inhibition of PTP or inhibiting the rise in mitochondrial calcium or reactive oxygen species that activate PTP have been proposed. A major limitation of inhibiting the PTP is the lack of knowledge about the identity of the protein(s) that form the PTP and how they are activated by calcium and reactive oxygen species. This review will critically evaluate the candidates for the pore-forming unit of the PTP and discuss recent data suggesting that assumption that the PTP is formed by a single molecular identity may need to be reconsidered.

Perfused murine heart optical transmission spectroscopy using optical catheter and integrating sphere: Effects of ischemia/reperfusion

Tissue transmission optical absorption spectroscopy provides dynamic information on metabolism and function. Murine genetic malleability makes it a major model for heart research. The diminutive size of the mouse heart makes optical transmission studies challenging. Using a perfused murine heart center mounted in an integrating sphere for light collection with a ventricular cavity optical catheter as an internal light source provided an effective method of optical data collection in this model. This approach provided high signal to noise optical spectra which when fit with model spectra provided information on tissue oxygenation and redox state. This technique was applied to the study of cardiac ischemia and ischemia reperfusion which generates extreme heart motion, especially during the ischemic contracture. The integrating sphere reduced motion artifacts associated with a fixed optical pickup and methods were developed to compensate for changes in tissue thickness. During ischemia, rapid decreases in myoglobin oxygenation occurred along with increases in cytochrome reduction levels. Surprisingly, when ischemic contracture occurred, myoglobin remained fully deoxygenated, while the cytochromes became more reduced consistent with a further, and critical, reduction of mitochondrial oxygen tension during ischemic contraction. This optical arrangement is an effective method of monitoring murine heart metabolism.

Larotrectinib in adult patients with solid tumours: a multi-centre, open-label, phase I dose-escalation study

BACKGROUND

NTRK1, NTRK2 and NTRK3 gene fusions (NTRK gene fusions) occur in a range of adult cancers. Larotrectinib is a potent and highly selective ATP-competitive inhibitor of TRK kinases and has demonstrated activity in patients with tumours harbouring NTRK gene fusions.

PATIENTS AND METHODS

This multi-centre, phase I dose escalation study enrolled adults with metastatic solid tumours, regardless of NTRK gene fusion status. Key inclusion criteria included evaluable and/or measurable disease, Eastern Cooperative Oncology Group performance status 0-2, and adequate organ function. Larotrectinib was administered orally once or twice daily, on a continuous 28-day schedule, in increasing dose levels according to a standard 3 + 3 dose escalation scheme. The primary end point was the safety of larotrectinib, including dose-limiting toxicity.

RESULTS

Seventy patients (8 with tumours with NTRK gene fusions; 62 with tumours without a documented NTRK gene fusion) were enrolled to 6 dose cohorts. There were four dose-limiting toxicities; none led to study drug discontinuation. The maximum tolerated dose was not reached. Larotrectinib-related adverse events were predominantly grade 1; none were grade 4 or 5. The most common grade 3 larotrectinib-related adverse event was anaemia [4 (6%) of 70 patients]. A dose of 100 mg twice daily was recommended for phase II studies based on tolerability and antitumour activity. In patients with evaluable TRK fusion cancer, the objective response rate by independent review was 100% (eight of the eight patients). Eight (12%) of the 67 assessable patients overall had an objective response by investigator assessment. Median duration of response was not reached. Larotrectinib had limited activity in tumours with NTRK mutations or amplifications. Pharmacokinetic analysis showed exposure was generally proportional to administered dose.

CONCLUSIONS

Larotrectinib was well tolerated, demonstrated activity in all patients with tumours harbouring NTRK gene fusions, and represents a new treatment option for such patients.

CLINCALTRIALS.GOV NUMBER

NCT02122913.

3D organ modeling with open-source software

To date, 3D organ modeling has not reached widespread clinical use, despite showing promise in medical literature. The majority of anatomic modeling that is presented in the literature is performed with proprietary software, presenting certain barriers to use, such as price for usage rights. Open-source software not only circumvents this barrier, but also often provides greater customization offered by global communities. In this proof-of-concept experiment, a HeartMate II LVAD inflow cannula was "virtually fit" in a patient's left ventricle using only open-source software. Open-source programs provide a legitimate alternative to the proprietary software options.

Genetic Drivers of Pancreatic Cancer Are Identical Between the Primary Tumor and a Secondary Lesion in a Long-Term (>5 Years) Survivor After a Whipple Procedure

Background: A new mass in the remnant pancreas of a patient with previously resected pancreatic ductal adenocarcinoma (PDA) typically represents either a recurrence of the initial primary tumor or a second primary tumor. Recent advances in next-generation sequencing (NGS) strategies allow us to compare the genetic makeup of primary and secondary lesions. Case presentation: A 50-year-old Caucasian female presented for a surgical evaluation of a new biopsy-proven PDA at the junction of the body and tail of the pancreas. Six years prior, in 2011, the patient was found to have a T3N0M0 PDA of the pancreatic head, which was surgically resected with a classic Whipple procedure and concurrent hemicolectomy. Pathology showed pancreatic intraepithelial neoplasia grade 2 and PDA with negative surgical margins, positive perineural spread, and negative lymphovascular spread, and the patient received adjuvant chemotherapy and local radiation. In 2017, she was diagnosed with a new PDA lesion in the remaining pancreatic body far from the previous anastomosis site and was taken to surgery for a completion pancreatectomy and revision of the gastrojejunostomy. NGS was performed on both specimens. Both lesions shared identical mutations in KRAS, TP53, and CDKN2A genes. Amplifications of MYC and mutant KRAS were identified in the 2017 tumor and an ACVR1B mutation was identified in the 2011 tumor, but was not found in the 2017 tumor. Conclusions: This case demonstrates the ability to evaluate similarities between key genetic drivers from a resected primary tumor and a PDA lesion that presented in the same patient 6 years later. Histological analysis and NGS can be used to understand potential differences and similarities between lesions and may be useful in future studies as predictive markers or to provide insight into resistance mechanisms (e.g., MYC amplification).

Adherence to Inpatient Venous Thromboembolism Prophylaxis: A Single Institution’s Concurrent Review

Hospital-acquired venous thromboembolism (VTE) affects morbidity and mortality and increases health care costs. Poor adherence to recommended prophylaxis may be a potential cause of ongoing events. This study aims to identify institutional adherence rates and barriers to optimal VTE prophylaxis. The authors performed patient and nurse interviews and a concurrent review of clinical documentation, utilizing a cloud-based, HIPAA-compliant tool, on a convenience sample of hospitalized patients. Adherence and agreement between different assessment modalities were calculated. Seventy-six patients consented for participation. Nurse documented adherence was 66% (29/44), 44% (27/61), and 89% (50/56) for mechanical, ambulatory, and chemoprophylactic prophylaxis, respectively. Patient report and nurse documentation showed moderate agreement for mechanical and no agreement for ambulatory adherence (κ = 0.51 and 0.07, respectively). Concurrent review using a cloud-based tool can provide robust, timely, and relevant information on adherence to recommended VTE prophylaxis. Iterative concurrent reviews can guide efforts to improve adherence and reduce rates of hospital-acquired VTE.

Is nonoperative management of partial distal biceps tears really successful?

BACKGROUND

The current treatment of partial distal biceps tears is a period of nonoperative management, followed by surgery, if symptoms persist. Little is known about the success rate and outcomes of nonoperative management of this illness.

METHODS

We identified 132 patients with partial distal biceps tears through an International Classification of Diseases, Ninth Revision code query of our institution's database. Patient records were reviewed to abstract demographic information and confirm partial tears of the distal biceps tendon based on clinical examination findings and confirmatory magnetic resonance imaging (MRI). Seventy-four patients completed an outcome survey.

RESULTS

In our study, 55.7% of the contacted patients who tried a nonoperative course (34 of 61 patients) ultimately underwent surgery, and 13 patients underwent immediate surgery. High-need patients, as defined by occupation, were more likely to report that they recovered ideally if they underwent surgery, as compared with those who did not undergo surgery (odds ratio, 11.58; P = .0138). For low-need patients, the same analysis was not statistically significant (P = .139). There was no difference in satisfaction scores between patients who tried a nonoperative course before surgery and those who underwent immediate surgery (P = .854). An MRI-diagnosed tear of greater than 50% was a predictor of needing surgery (odds ratio, 3.0; P = .006).

CONCLUSIONS

This study has identified clinically relevant information for the treatment of partial distal biceps tears, including the following: the failure rate of nonoperative treatment, the establishment of MRI percent tear as a predictor of failing nonoperative management, the benefit of surgery for the high-need occupational group, and the finding that nonoperative management does not negatively affect outcome if subsequent surgery is necessary.

First-in-human phase 1 study of margetuximab (MGAH22), an Fc-modified chimeric monoclonal antibody, in patients with HER2-positive advanced solid tumors

Background

Margetuximab is an anti-HER2 antibody that binds with elevated affinity to both the lower and higher affinity forms of CD16A, an Fc-receptor important for antibody dependent cell-mediated cytotoxicity (ADCC) against tumor cells. A Phase 1 study was initiated to evaluate the toxicity profile, maximum tolerated dose (MTD), pharmacokinetics, and antitumor activity of margetuximab in patients with HER2-overexpressing carcinomas.

Patients and methods

Patients with HER2-positive breast or gastric cancer, or other carcinomas that overexpress HER2, for whom no standard therapy was available, were treated with margetuximab by intravenous infusion at doses of 0.1-6.0 mg/kg for 3 of every 4 weeks (Regimen A) or once every 3 weeks (10-18 mg/kg) (Regimen B).

Results

Sixty-six patients received margetuximab (34 patients for Regimen A and 32 patients for Regimen B). The MTD was not reached for either regimen. Treatment was well-tolerated, with mostly Grade 1 and 2 toxicities consisting of constitutional symptoms such as pyrexia, nausea, anemia, diarrhea, and fatigue. Among 60 response-evaluable patients, confirmed partial responses and stable disease were observed in 7 (12%) and 30 (50%) patients, respectively; 26 (70%) of these patients had received prior HER2-targeted therapy. Tumor reductions were observed in over half (18/23, 78%) of response-evaluable patients with breast cancer including durable (>30 weeks) responders. Ex vivo analyses of patient peripheral blood mononuclear cell samples confirmed the ability of margetuximab to support enhanced ADCC compared with trastuzumab.

Conclusions

Margetuximab was well-tolerated and has promising single-agent activity. Further development efforts of margetuximab as single agent and in combination with other therapeutic agents are ongoing.

Trial Registration ID

NCT01148849.

Hepatitis C virus infection in intravenous drug users

Intravenous drug use (IVDU) remains a major means of hepatitis C virus (HCV) transmission. In this study, 101 drug users were studied prospectively after cessation of IVDU. Of these, 75.8% were anti-HCV positive, and 71.4% had elevated levels of alanine aminotransferase. These levels decreased significantly within 1 month of IVDU cessation (p 0.02). Liver biopsies showed minimal or mild fibrosis in 32 (71%) of 45 subjects, and severe fibrosis in two (4.4%) subjects. Anti-HCV-positive intravenous drug users in this study presented with mild liver disease and variable stages of disease progression. Biochemical disease activity might be affected by IVDU.

Small intestinal bacterial overgrowth in patients with cirrhosis: prevalence and relation with spontaneous bacterial peritonitis

OBJECTIVES

The significance of small intestinal bacterial overgrowth in patients with cirrhosis is not fully understood and its diagnostic criteria are not uniform. We examined the association of small intestinal bacterial overgrowth with spontaneous bacterial peritonitis and compared various microbiological criteria.

METHODS

Jejunal secretions from 70 patients with cirrhosis were cultivated quantitatively and classified according to various definitions. Clinical characteristics of patients were evaluated and the incidence of spontaneous bacterial peritonitis was monitored during a 1-yr follow-up.

RESULTS

Small intestinal bacterial overgrowth, defined as > or = 10(5) total colony-forming units/ml jejunal secretions, was present in 61% of patients. Small intestinal bacterial overgrowth was associated with acid-suppressive therapy (p = 0.01) and hypochlorhydria (p < 0.001). Twenty-nine patients with persistent ascites were observed. Six episodes of spontaneous bacterial peritonitis occurred after an average 12.8 wk. Occurence of spontaneous bacterial peritonitis correlated with ascitic fluid protein concentration (p = 0.01) and serum bilirubin (p = 0.04) but not with small intestinal bacterial overgrowth (p = 0.39). Its association with acid-suppressive therapy was of borderline significance (hazard ratio = 7.0, p = 0.08).

CONCLUSIONS

Small intestinal bacterial overgrowth in cirrhotic patients is associated with acid-suppressive therapy and hypochlorhydria, but not with spontaneous bacterial peritonitis. The potential role of acid-suppressive therapy in the pathogenesis of spontaneous bacterial peritonitis merits further studies.

Derivation and validation of guidelines for stool cultures for enteropathogenic bacteria other than Clostridium difficile in hospitalized adults

CONTEXT

The yield of in-hospital stool cultures performed more than 72 hours after admission is low, and a commonly used policy dictates that laboratories reject these cultures to save costs. However, enteropathogenic bacteria other than Clostridium difficile (EPB) may cause nosocomial illness that would be missed by use of such a "3-day rule."

OBJECTIVE

To develop guidelines for hospital use of stool cultures that are sensitive to clinically relevant cases of sporadic and epidemic nosocomial diarrhea.

DESIGN

Five-part study that incorporated a derivation sample based on retrospective chart review and a prospective cohort study (including cost savings analysis), and a validation sample based on retrospective chart review.

SETTING

Four European academic health care centers.

PATIENTS

Derivation sample: 1735 adult inpatients from whom 3416 stool cultures were obtained during a 19-month period (1995-1997) and 68 adult inpatients for whom EPB were grown from stool cultures during a 10-year period (1988-1998); validation sample: 65 patients with sporadic isolation of EPB (1993-1998), 56 patients involved in 2 nosocomial Salmonella outbreaks (1992 and 1997), and 330 patients who had stool cultures performed (1998).

MAIN OUTCOME MEASURE

Performance of derived criteria in detecting pathogenic bacteria and outbreaks and reducing total number of stool cultures performed.

RESULTS

Stool cultures grew EPB in 3.3% of samples obtained </=72 hours after admission and 0.5% of samples obtained thereafter (P<.001). Isolation of EPB >72 hours after admission was not associated with clinical symptoms or signs but was associated with community-acquired diarrhea (24%), age 65 years or older with preexisting comorbid disease (25%), neutropenia (13%), HIV infection (10%), and nondiarrheal manifestations of enteric infections (16%). Twelve percent were asymptomatic carriers. These characteristics were used to create criteria for selecting patients for whom stool cultures would be indicated. These criteria were applied post hoc to a series of 1025 stool cultures; the number of stool cultures would have been reduced by 52% and no clinically significant cases would have been missed. Annual savings to a 355-bed institution would be approximately $7800 for reagent costs and 75 hours of technician time. In the validation samples, only 2 patients of 65 who had EPB would not have been identified, and neither required treatment. If the 3-day rule had been applied, 52 cases would not have been identified, 28 of which required antibiotic treatment.

CONCLUSION

Our modified 3-day rule for use in selecting cases for stool culture is sensitive to sporadic and epidemic cases of nosocomial diarrhea in hospitalized adults.

Bacterial translocation of enteric organisms in patients with cirrhosis

BACKGROUND/AIMS

The aim of the study was to investigate the prevalence and associated risk factors for bacterial translocation in patients with cirrhosis, a mechanism involved in the pathogenesis of bacterial infections in experimental cirrhosis.

METHODS

Mesenteric lymph nodes were obtained for microbiological culture from 101 patients with cirrhosis and from 35 non-cirrhotic patients.

RESULTS

Enteric organisms were grown from mesenteric lymph nodes in 8.6% of non-cirrhotic patients. In the 79 cirrhotic patients without selective intestinal decontamination, the prevalence of bacterial translocation significantly increased according to the Child-Pugh classification: 3.4% in Child A, 8.1% in Child B and 30.8% in Child C patients (chi2 = 6.106, P < 0.05). However, translocation by Enterobacteriaceae, the organisms commonly responsible for spontaneous bacteremia and peritonitis in cirrhosis, was only observed in 25% of the cases. The prevalence of bacterial translocation in the 22 cirrhotic patients undergoing selective intestinal decontamination, all Child-Pugh class B and C, was 4.5%. The Child-Pugh score was the only independent predictive factor for bacterial translocation (odds ratio 2.22, P = 0.02).

CONCLUSIONS

Translocation of enteric organisms to mesenteric lymph nodes is increased in patients with advanced cirrhosis and is reduced to the level found in non-cirrhotic patients by selective intestinal decontamination.

Diagnosis, treatment and prevention of spontaneous bacterial peritonitis

Spontaneous bacterial peritonitis (SBP) is a frequent complication in cirrhotic patients with ascites. Diagnosis of SBP is established by a polymorphonuclear cell count in ascitic fluid > or =250 cells/mm(3). The organism responsible for the infection is isolated in 60-70% of the cases. The remaining cases are considered to have a variant of SBP (culture-negative SBP) and are treated in the same way as those with a positive culture. The SBP resolution rate ranges between 70 and 90%, and hospital survival between 50 and 70%. An early diagnosis and the use of a more adequate antibiotic therapy are the most probable reasons for the improvement in prognosis for SBP in recent decades. Despite the resolution of the infection, SBP may trigger severe complications such as renal impairment, gastrointestinal bleeding and accentuation of hepatic insufficiency which are responsible for the associated mortality. Patients recovering from an episode of SBP should be considered as potential candidates for liver transplantation.

[Chronic diarrhea: therapy with antibiotics]

Chronic diarrhoea in developed countries is most frequently caused by organic or functional disorders. Infectious agents are infrequently involved, and antibiotic chemotherapy should therefore generally rest on a microbiological diagnosis. However, there may be a role for empirical antibiotic treatment in well defined circumstances such as persistent traveller's diarrhoea or suspected small intestinal bacterial overgrowth.

Diagnosis of small intestinal bacterial overgrowth in patients with cirrhosis of the liver: poor performance of the glucose breath hydrogen test

BACKGROUND/AIMS

Small intestinal bacterial overgrowth is known to occur in association with cirrhosis of the liver and studies are needed to assess its pathophysiological role. The glucose breath hydrogen test as an indirect test for small intestinal bacterial overgrowth has been applied to patients with cirrhosis but has not yet been validated against quantitative culture of jejunal secretion in this particular patient population.

METHODS

Forty patients with cirrhosis underwent glucose breath hydrogen test and jejunoscopy. Jejunal secretions were cultivated quantitatively for aerobe and anaerobe microorganisms.

RESULTS

Small intestinal bacterial overgrowth was detected by culture of jejunal aspirates in 73% of patients, being associated with age and the administration of acid-suppressive therapy. The glucose breath hydrogen test correlated poorly with culture results, sensitivity and specificity ranging from 27%-52% and 36%-80%, respectively.

CONCLUSIONS

In patients with cirrhosis, the glucose breath hydrogen test correlates poorly with the diagnostic gold standard for small intestinal bacterial overgrowth. Until other non-invasive tests have been validated, studies addressing the role of small intestinal bacterial overgrowth in patients with cirrhosis should resort to microbiological culture of jejunal secretions.

Vertebral osteomyelitis caused by group B streptococci (Streptococcus agalactiae) secondary to urinary tract infection

Infections due to group B streptococci usually occur in the peri- and neonatal setting or in adults with chronic underlying diseases. A case of pyogenic vertebral osteomyelitis caused by Streptococcus agalactiae in a 54-year-old man suffering from phimosis with urinary retention and urinary tract infection is reported. This case adds to the few existing reports of vertebral osteomyelitis caused by group B streptococci.

Drug-induced hepatocellular liver injury due to benzylpenicillin with evidence of lymphocyte sensitization

BACKGROUND/AIMS

Reports on drug-induced liver injury due to benzylpenicillin are scarce and predominantly describe cases of intrahepatic cholestasis. To our knowledge, no immunologically documented case of hepatocellular liver injury due to benzylpenicillin has been reported so far.

CASE REPORT

A previously healthy man required long-term therapy with benzylpenicillin because of vertebral spondylitis. After 4 weeks of treatment, liver tests showed a marked increase in transaminases associated with high peripheral eosinophil counts. Discontinuation of benzylpenicillin resulted in gradual recovery.

INVESTIGATIONS

Levels of eosinophil cationic protein were elevated, indicating eosinophil activation and the presence of an immunoallergic reaction. Skin tests and assays for specific Ig E-antibodies to benzylpenicillin were negative, but lymphocyte transformation tests demonstrated T-cell sensitization to benzylpenicillin.

CONCLUSIONS

According to current causality assessment schemes, our report constitutes a probable case of drug-induced hepatocellular liver injury due to benzylpenicillin.

Invasive candidiasis complicating spontaneous esophageal perforation (Boerhaave syndrome)

Spontaneous esophageal perforation is a rare condition that frequently results in infectious complications. Empirical broad-spectrum antibacterial therapy is therefore part of the standard management. We describe two patients suffering from spontaneous esophageal perforation who developed invasive candidiasis with hematogenous dissemination. One patient died of multiple organ failure due to Candida sepsis. Preexistent Candida colonization, incomplete mediastinal drainage, broad-spectrum antibacterial therapy, and prolonged intensive care therapy place patients with esophageal perforation at high risk for secondary fungal infection. Intense microbiological searching is mandatory, but the distinction between colonization and infection may be impossible. Empirical antifungal treatment with imidazole derivatives, particularly in patients with potential risk factors, should be considered.

Prolonged sedation due to accumulation of conjugated metabolites of midazolam

Midazolam is a short-acting benzodiazepine routinely used in intensive-care medicine. Conjugates of its main metabolite, alpha-hydroxymidazolam, have been shown to accumulate in renal failure but have not previously been related to the prolonged sedative effects commonly observed in critically ill patients. We report five patients with severe renal failure who had prolonged sedation after administration of midazolam. In all five patients, the comatose state was immediately reversed by the benzodiazepine-receptor antagonist flumazenil. Serum concentration monitoring showed high concentrations of conjugated alpha-hydroxymidazolam when concentrations of the unconjugated metabolite and the parent drug were below the therapeutic range. In-vitro binding studies showed that the affinity of binding to the cerebral benzodiazepine receptor of glucuronidated alpha-hydroxymidazolam was only about ten times weaker (affinity constant 16 nmol/L) than that of midazolam (1.4 nmol/L) or unconjugated alpha-hydroxymidazolam (2.2 nmol/L). Conjugated metabolites of midazolam have substantial pharmacological activity. Physicians should be aware that these metabolites can accumulate in patients with renal failure.

[Neurocysticercosis]

A 49-year-old woman from Croatia, resident in Switzerland for 22 years, had a history of headaches and arterial hypertension for 8 years. While in hospital for assessment and treatment she developed focal seizures. She had an eosinophilia (10%) and computed tomography of the skull demonstrated cysts and multiple calcified foci in the left cerebral hemisphere. Antibodies against Taenia solium antigen were found in both serum and cerebrospinal fluid. Anthelminthic treatment with albendazole (15 mg/kg daily for 25 days) and anticonvulsive treatment with phenytoin (serum levels between 10 and 20 mg/l) markedly improved the symptoms and the cysts regressed. Neurocysticercosis, caused by the larvae of the pork tapeworm, is occurring even more frequently because of the migration of people from countries where the disease is endemic.

[Quality control by autopsy. How often do the postmortem examination findings correct the clinical diagnosis?]

To ascertain whether autopsies still provide important information in the face of modern diagnostic procedures, the findings in 780 autopsies (543 men and 237 women: mean age 58 [1-94] years), performed between 1977 and 1990, were compared with the clinical diagnoses. Autopsy confirmed the clinical diagnosis in 74.9% of cases, a clinically not diagnosed basic disease was demonstrated in 13.6%, and a not recognized final complication in 11.5%. In 9.7% of autopsies previously unrecognized but clinically important additional diseases were found. There was no decrease in the proportion of unrecognized basic diseases in the course of the observation period. It was unrelated to the duration of hospital stay, but increased with increasing age of the patients. These observations indicate that even nowadays, in the age of highly technical medicine, autopsies point to any limitations of diagnosis and are thus of importance for clinical quality control.

Interleukin-6 release by rat liver macrophages

Tissue macrophages of the liver (Kupffer cells) release interleukin-6 (IL-6) in vitro. Since Kupffer cells reside in close proximity to hepatocytes, which are major target cells of IL-6, the regulation of IL-6 release by hepatic macrophages has been investigated in this study. Using the hybridoma growth test to detect IL-6, we found that Kupffer cells already maximally release IL-6 at endotoxin concentrations as low as 1.0 ng/ml. The stimulated secretion of IL-6 was increased 4-8-fold by endotoxin when compared to the control macrophages incubated in serum-containing medium alone. The preincubation of macrophages with interferon-gamma enhanced the capacity of Kupffer cells to respond to endotoxin. The secretion of IL-6 could also be induced by interleukin (IL)-1 beta and tumor necrosis factor (TNF-alpha). The most potent inducers, however, were the paramyxoviruses Newcastle Disease Virus and Sendai Virus. The release of IL-6 by macrophages upon stimulation with endotoxin was almost completely inhibited by 1 microM dexamethasone. Whereas 100 nM of prostaglandin E2 (PGE2) inhibited the release of TNF-alpha in rat Kupffer cells, it did not affect the secretion of IL-6.

An epidemiological study assessing the relative importance of airborne and direct contact transmission of microorganisms in a medical intensive care unit

A prospective epidemiological survey was carried out over a period of seven weeks in a medical intensive care unit. Bacteria from patients, staff and air were monitored and the transmission of isolated microorganisms was followed. Handwashing samples revealed pathogenic bacteria in 30.8% of physicians (average number of colony forming units: 71,300 per hand) and 16.6% of nurses (39,800 cfu per hand). Air cultures yielded pathogens in 15% of sampling periods and nine of 53 patients were found to be colonized with Gram-negative bacteria, Staphylococcus aureus or Candida spp. The spectrum of bacteria recovered from patients and air was generally different, whereas strains recovered from patients and their attendants' hands were indistinguishable on multiple occasions. The results of this study confirm that direct contact is the principal pathway of microbial transmission, whereas little evidence for a significant role of airborne transmission is shown. The call for more extensive air-filtering and ventilation systems in medical intensive care units is not supported by the results shown in this communication.

Regulation of interleukin 6 receptor expression in human monocytes and monocyte-derived macrophages. Comparison with the expression in human hepatocytes

IL-6 is a cytokine with pleiotropic biological functions, including induction of the hepatic acute phase response and differentiation of activated B cells into Ig-secreting plasma cells. We found that human peripheral blood monocytes express the IL-6-R, which is undetectable on the large majority of lymphocytes of healthy individuals. Stimulation of monocytes by endotoxin or IL-1 causes a rapid downregulation of IL-6-R mRNA levels and a concomitant enhancement of IL-6 mRNA expression. IL-6 itself was found to suppress the IL-6-R at high concentrations. A gradual decrease of IL-6-R mRNA levels was observed along in vitro maturation of monocytes into macrophages. We show that downregulation of IL-6-R mRNA levels by IL-1 and IL-6 is monocyte specific, since IL-6-R expression is stimulated by both IL-1 and IL-6 in cultured human primary hepatocytes. Our data indicate that under noninflammatory conditions, monocytes may play a role in binding of trace amounts of circulating IL-6. Repression of monocytic IL-6-R and stimulation of hepatocytic IL-6-R synthesis may represent a shift of the IL-6 tissue targets under inflammatory conditions.