Rate and predictors of blood culture positivity after antibiotic administration: a prospective single-center study

PURPOSE

Blood culture obtainment prior to antibiotic administration, in patients with suspected infection, is considered the best practice in international guidelines. However, there is little data regarding the effect of a single dose of antibiotics on blood culture sterilization.

METHODS

We conducted a prospective study, enrolling consecutive patients with suspected infection, hospitalized in an internal medicine ward between December 2019 and January 2023. Included patients had a positive blood culture prior to antibiotic administration and a set of blood cultures taken within 24 h after a single dose of antibiotics. The rate of patients with pathogen isolation after antibiotic administration was assessed. Logistic regression was performed to examine factors associated with blood culture positivity.

RESULTS

A total of 155 patients were recruited for the study of which 131 (50.8% female 77.5 ± 13.4 years) met the inclusion criteria. The overall rate of patients with a positive blood culture after a single dose of antibiotics was 42.0% (55/131 patients). Increasing time between antibiotic administration and post-antibiotic culture was an independent predictor for blood culture sterilization (odds ratio 0.89 [95% confidence interval, 0.83-0.97; p = 0.006] for every 60 min). Blood culture volume was an independent predictor for blood culture positivity in a sensitivity analysis which included 82 patients (OR = 1.26 [95% CI 1.03-1.57] for every 1 ml increase; p = 0.024).

CONCLUSION

Blood culture positivity is reduced by antimicrobial therapy but remains high after a single dose of antibiotics. If cultures are not obtained prior to antibiotic administration, they should be obtained as soon as possible afterwards.

An old diagnostic tool for new indications: inpatient Holter ECG for conditions other than syncope or stroke

Holter electrocardiography (ECG) assists in the diagnosis of arrhythmias. Its use in the inpatient setting has been described solely for the evaluation of stroke and syncope. Our aim was to assess its diagnostic value for other conditions in the internal medicine department. We included all hospitalized patients between 2018 and 2021 in a tertiary referral center. The primary outcome was a diagnostic Holter recording a new arrhythmia that led to a change in treatment. Overall, 289 patients completed a 24-h inpatient Holter ECG for conditions other than syncope or stroke, with 39 (13%) diagnostic findings. The highest diagnostic value was found in patients admitted for pre-syncope (19%), palpitations (18%), and unexplained heart failure exacerbation/dyspnea (17%). A low diagnostic yield was found for the evaluation of chest pain (5%). Heart failure with preserved ejection fraction (adjusted OR 2.3, 95% CI 1.1-5.4, p = 0.04), and baseline ECG with either a bundle branch block (AOR 4.2, 95% CI 1.9-9.2, p < 0.01) or atrioventricular block (first or second degree, AOR 5, 95% CI 2.04-12.3, p < 0.01) were among the independent predictors for a diagnostic test. Inpatient Holter ECG monitoring may have value as a diagnostic tool for selected patients with conditions other than syncope or stroke.

Serial Measurements of Neutrophil Gelatinase-Associated Lipocalin levels for Assessment of Contrast Induced Nephropathy among Chronic Kidney Disease Patients Who Underwent Elective Coronary Angiography

BACKGROUND

Among chronic kidney disease (CKD) patients, baseline neutrophil gelatinase-associated lipocalin (NGAL) may reflect the severity of renal impairment. No data exists on serial changes in serum NGAL levels in CKD patients before and after percutaneous coronary intervention (PCI).

OBJECTIVES

To evaluate serial serum NGAL levels relation to contrast induced acute kidney injury (CI-AKI) following PCI.

METHODS

The study included 58 patients with CKD who underwent elective PCI. Plasma NGAL measurements were performed before (pre-NGAL) and 24 hours following (post-NGAL) PCI. Patients were followed for CI-AKI and changes in NGAL levels. Receiver operator characteristic identified the optimal sensitivity and specificity for pre-NGAL levels compared with post-NGAL for patients with CI-AKI.

RESULTS

Overall CI-AKI incidence was 33%. Both pre-NGAL (172 vs. 119 ng/ml, P < 0.001) and post-NGAL (181 vs. 121 ng/ml, P < 0.001) levels were significantly higher in patients with CI-AKI, but no significant changes were detected. Pre-NGAL levels were similar to post-NGAL levels in predicting CI-AKI (area under the curve 0.753 vs. 0.745). Optimal cutoff value for pre-NGAL was 129 ng/ml (sensitivity of 73% and specificity of 72%, P < 0.001). Post-NGAL levels > 141 ng/ml were independently associated with CI-AKI (hazard ratio [HR] 4.86, 95% confidence interval [95%CI] 1.34-17.64, P = 0.02) with a strong trend for post-NGAL levels > 129 ng/ml (HR 3.46, 95%CI 1.23-12.81, P = 0.06).

CONCLUSIONS

In high-risk patients, pre-NGAL levels may predict CI-AKI. Further studies on larger populations are needed to validate the use of NGAL measurements in CKD patients.

Safety and outcomes of an early discharge strategy with oxygen home therapy in stable severe COVID-19 patients

BACKGROUND

COVID-19 disease leads to prolonged hospitalisations and adverse outcomes. We describe our strategy for routine early discharge of severe COVID-19 patients with home oxygen during the Delta variant surge.

METHODS

Our strategy included COVID-19 patients requiring oxygen support via nasal cannula, with stabilised but not yet improved respiration (intervention group), that followed strict criteria. Severe COVID-19 patients discharged after improved respiration were considered the control group for comparison. Outcomes included readmissions from active COVID-19 and 30-day mortality.

RESULTS

The intervention group included 129 patients, and the control 150. The groups' baseline characteristics were similar, although the control group had more advanced COVID-19 severity. Among the intervention group, 23 (17.8%) had readmissions secondary to active COVID-19, compared to none in the control group. The 30-day mortality rate was similar between the groups (5% vs. 7%). The intervention led to a shorter hospital stay [median 3 days (IQR 2-4) vs. 6 days (IQR 4-9), p < .01], while a very short hospitalisation was associated with readmissions (2.8 vs. 3.5 days, p = .02). A subsequent critical disease or death after the intervention occurred in old (81 years), multimorbid (3.4 ± 1.4) patients with a high percentage of acute kidney injury during their first hospitalisation (50%).

CONCLUSIONS

Our discharge strategy led to a short hospital stay, a high readmission rate, and similar long-term outcomes. Considering the difference in disease severity before discharge, this intervention cannot be considered safe for our study population. Correct patient selection is crucial to ensure patient safety when considering early discharge.

Diagnostic delays among COVID-19 patients with a second concurrent diagnosis

BACKGROUND

Little is known about the effect of a new pandemic on diagnostic errors.

OBJECTIVE

We aimed to identify delayed second diagnoses among patients presenting to the emergency department (ED) with COVID-19.

DESIGNS

An observational cohort Study.

SETTINGS AND PARTICIPANTS

Consecutive hospitalized adult patients presenting to the ED of a tertiary referral center with COVID-19 during the Delta and Omicron variant surges. Included patients had evidence of a second diagnosis during their ED stay.

MAIN OUTCOME AND MEASURES

The primary outcome was delayed diagnosis (without documentation or treatment in the ED). Contributing factors were assessed using two logistic regression models.

RESULTS

Among 1249 hospitalized COVID-19 patients, 216 (17%) had evidence of a second diagnosis in the ED. The second diagnosis of 73 patients (34%) was delayed, with a mean (SD) delay of 1.5 (0.8) days. Medical treatment was deferred in 63 patients (86%) and interventional therapy in 26 (36%). The probability of an ED diagnosis was the lowest for Infection-related diagnoses (56%) and highest for surgical-related diagnoses (89%). Evidence for the second diagnosis by physical examination (adjusted odds ratios [AOR] 2.35, 95% confidence interval [CI] 1.20-4.68) or by imaging (AOR 2.10, 95% CI 1.16-3.79) were predictors for ED diagnosis. Low oxygen saturation (AOR 0.38, 95% CI 0.18-0.79) and cough or dyspnea (AOR 0.48, 95% CI 0.25-0.94) in the ED were predictors of a delayed second diagnosis.

Effect of patient COVID-19 vaccine hesitancy on hospital care team perceptions

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic posed new challenges in patient care worldwide. Vaccinations, which have proven efficacious in lowering the COVID-19 hospital burden, are still avoided by large populations. We, therefore, hypothesized that hospital care teams would have worse perceptions regarding the characteristics and care of patients with vaccine hesitancy.

AIM

To evaluate whether patient vaccine hesitancy affected the hospital care team (HCT) perceptions.

METHODS

We performed a prospective clinical study using structured questionnaires. We approached physicians and nurses with previous experience caring for COVID-19 patients from 11 medical centers across Israel during the fourth COVID-19 surge (September and October 2021). The participants completed a questionnaire with the following parts: (1) Sociodemographic characteristics; (2) Assessment of anger (STAXI instrument) and chronic workplace stress (Shirom-Melamed burnout measure); and (3) Three tools to assess the effect of patient vaccine hesitancy on the HCT perceptions (the difficult doctor-patient relation questionnaire, the medical staff perception of patient’s responsibility questionnaire and the characterological derogation questionnaire). Results were evaluated according to each part of the questionnaire and the questionnaire as a whole. Associations between HCT perceptions and their baseline characteristics, anger or chronic workplace stress were assessed.

RESULTS

The HCT experienced their relationship with unvaccinated patients as more difficult (P < 0.001, Cohen’s d = 0.85), perceived unvaccinated patients as responsible for their medical condition (P < 0.001, d = 1.39) and perceived vaccinated patients as having a higher character value (P < 0.001, d = 1.03). Unvaccinated patients were considered selfish (P < 0.001), less mature (P < 0.001) and less satisfying to care for (P < 0.001). The relationship with unvaccinated patients was more difficult among HCT with higher burnout (r = 0.37, n = 66, P = 0.002). No correlations with baseline characteristics were found. All three study tools showed high internal consistency (α between 0.72 and 0.845).

CONCLUSION

Our results should raise awareness of the possible effects of vaccine hesitancy on HCT perceptions regarding unvaccinated patients. In order to minimize the potential negative impact on patient care, designated departments should promote specific patient-centered preparations. Further investigations should assess whether vaccine hesitancy directly affects patient quality of care.

Associations of vaccine status with characteristics and outcomes of hospitalized severe COVID-19 patients in the booster era

BACKGROUND

The resurgence of COVID-19 cases since June 2021, referred to as the fourth COVID-19 wave, has led to the approval and administration of booster vaccines. Our study aims to identify any associations between vaccine status with the characteristics and outcomes of patients hospitalized with severe COVID-19 disease.

METHODS

We retrospectively reviewed all COVID-19 patients admitted to a large tertiary center between July 25 and October 25, 2021 (fourth wave in Israel). Univariant and multivariant analyses of variables associated with vaccine status were performed.

FINDINGS

Overall, 349 patients with severe or critical disease were included. Patients were either not vaccinated (58%), had the first two vaccine doses (35%) or had the booster vaccine (7%). Vaccinated patients were significantly older, male predominant, and with a higher number of comorbidities including diabetes, hyperlipidemia, ischemic heart disease, heart failure, immunodeficient state, kidney disease and cognitive decline. Time from the first symptom to hospital admission was longer among non-vaccinated patients (7.2 ± 4.4 days, p = 0.002). Critical disease (p<0.05), admissions to the intensive care unit (p = 0.01) and advanced oxygen support (p = 0.004) were inversely proportional to the number of vaccines given, lowest among the booster vaccine group. Death (20%, p = 0.83) and hospital stay duration (8.05± 8.47, p = 0.19) were similar between the groups.

CONCLUSION

Hospitalized vaccinated patients with severe COVID-19 had significantly higher rates of most known risk factors for COVID-19 adverse outcomes. Still, all disease outcomes were similar or better compared with the non-vaccinated patients.

Relation of Baseline Neutrophil Gelatinase-Associated Lipocalin (NGAL) Levels and Contrast-Induced Nephropathy following Percutaneous Coronary Intervention among Chronic Kidney Disease Patients

BACKGROUND

The risk of contrast-induced acute kidney injury (CI-AKI) following coronary intervention is particularly high among patients with chronic kidney disease (CKD). Among these patients, baseline neutrophil gelatinase-associated lipocalin (NGAL), a marker of tubular damage, reflects the severity of renal impairment. We evaluated whether the baseline serum NGAL level may be a marker for the development of CI-AKI following percutaneous coronary intervention (PCI).

METHODS

Eighty-eight CKD patients treated with PCI were included. Serum NGAL levels were drawn upon hospital admission. Receiver operator characteristic (ROC) methods were used to identify the optimal sensitivity and specificity for the observed NGAL level compared with the estimated glomerular filtration rate (eGFR) calculated for patients with CI-AKI.

RESULTS

Overall CI-AKI incidence was 43%. Baseline serum NGAL levels were significantly higher in patients with CI-AKI than in patients without CI-AKI (150 vs. 103 ng/mL, p < 0.001). According to the ROC curve, baseline NGAL levels performed better than eGFR to predict CI-AKI (AUC 0.753 vs. 0.604), with the optimal cutoff value for baseline NGAL to predict CI-AKI being 127 ng/mL (sensitivity of 68% and specificity of 68%, p < 0.001). In a multivariate logistic regression model, the NGAL level >127 ng/mL ng/mL was independently associated with CI-AKI (HR 9.84, 95% CI: 1.96-40.3; p = 0.01).

CONCLUSION

Baseline serum NGAL levels in CKD patients may identify a high-risk population for CI-AKI following PCI. Further studies on larger populations are required to validate the potential utility of NGAL measurements in monitoring specific CKD-associated conditions.

Clinical and prognostic significance of elevated ferritin levels in hospitalised adults

PURPOSE OF THE STUDY

Elevated ferritin levels are associated with a variety of infectious, malignant and inflammatory diseases. We aimed to investigate the prognostic value of markedly elevated ferritin levels in hospitalised patients with various medical conditions.

STUDY DESIGN

Retrospective analysis of patients with a ferritin level higher than 2000 ng/mL hospitalised in Sheba Medical Center between 1 January 2007 and 31 December 2015. Medical conditions of these patients were recorded. In-hospital, 30-day and 1-year mortality rates were evaluated according to ferritin ranges and clinical categories.

RESULTS

The study included 722 patients (63.4% men) with a mean age of 63.9±16.7 years. The most common clinical conditions associated with markedly elevated ferritin were infectious diseases and malignancies. The highest mean ferritin levels were associated with rheumatological/inflammatory conditions (16 241.3 ng/dL), particularly in patients with macrophage activation syndrome (MAS) (96 615.5 ng/dL). In-hospital, 30-day and 1-year mortality rates were 32.3%, 46.7% and 70.8%, respectively. The highest in-hospital, 30-day and 1-year mortality rates were observed among patients with solid malignancies (40.1%, 64.7% and 90.3%, respectively), whereas the lowest rates were found among patients with rheumatological/inflammatory conditions, including MAS (21.4%, 38.1% and 45.2%, respectively). Ferritin levels were not associated with mortality.

CONCLUSIONS

In hospitalised patients, ferritin levels higher than 2000 ng/mL are mainly associated with infectious and malignant diseases but do not predict mortality.

Potential role for furosemide in the treatment of acute respiratory distress syndrome (ARDS) and an unusual presentation of pulmonary embolism in a complex patient

An 81-year-old woman was admitted to our hospital after experiencing syncope. She was diagnosed with a large pulmonary embolism and was hemodynamically unstable therefore requiring endotracheal intubation and norepinephrine support. She presented with an upper gastrointestinal bleed which prevented her from receiving tissue plasminogen activator. She was treated with enoxaparin and ceftriaxone. Her blood, sputum and urine cultures were negative. When transferred to our ward, her antibiotic treatment was changed to piperacillin–tazobactam. A lumbar puncture was not suggestive of a central nervous system infection. Chest X-rays demonstrated rapid advancement of diffuse bilateral infiltrates which were not present at first and were interpreted by radiology consultation as suggestive of acute respiratory distress syndrome. An echocardiography showed right ventricle dilatation without left-sided heart failure. Diuretics were added and with this treatment, a quick respiratory improvement was noted as she regained consciousness and extubated shortly after.

Incidence and risk factors of pneumothorax following pre-procedural ultrasound-guided thoracentesis

Background

Data regarding the incidence and risk factors of pneumothorax following pre-procedural ultrasound (US)-guided thoracentesis is scarce. We aimed to evaluate the incidence and risk factors of pneumothorax following pre-procedural US-guided thoracentesis in a tertiary medical center.

Methods

Retrospective analysis of patients who underwent pre-procedural US-guided thoracentesis in Sheba Medical Center between January 2016 and December 2018. Data collected included incidence of pneumothorax following thoracentesis, baseline clinical and demographic characteristics, and thoracentesis-associated factors. Outcomes evaluated included length of hospital stay, mortality, chest tube insertion and intensive care unit admission.

Results

A total of 550 patients with pleural effusions underwent pre-procedural US-guided thoracentesis. Sixty-six (12%) of them developed pneumothorax. Compared to patients who did not develop pneumothorax, those who developed pneumothorax had a higher rate of congestive heart failure (32.2% vs. 47%, P=0.026), a smaller depth of pleural fluid marking (3.4 vs. 3.2 cm, P=0.024), a larger amount of pleural fluid drained (1,093 vs. 903.5 mL, P=0.01), and were more likely to undergo bilateral procedures (7.6% vs. 2.3%, P=0.044). In the multivariate regression analysis, volume of pleural fluid drained was significantly associated with the development of pneumothorax (OR, 1.001, 95% CI, 1–1.001; P=0.042).

Conclusions

The incidence of pneumothorax following pre-procedural US-guided thoracentesis was relatively high in the present study. The amount of pleural fluid drained was the main factor associated with the risk of developing pneumothorax in these cases.

Cytokine expression in temporal arteries: comparative analysis between patients with biopsy-positive giant cell arteritis, biopsy-negative giant cell arteritis and biopsy-negative without arteritis

OBJECTIVES

To investigate whether expression of pro-inflammatory cytokines in the temporal artery may aid in differentiating biopsy-negative giant cell arteritis (GCA) patients from those with a negative biopsy without arteritis.

METHODS

We investigated cytokine expression in temporal artery biopsy (TAB) of 54 consecutive patients: 17 with biopsy-positive GCA, 17 with biopsy-negative GCA, and 20 biopsy-negative without arteritis. We compared the expression rate of the following cytokines among these 3 groups of patients: interleukin-6 (IL-6), osteopontin (OPN), COX-2, and TNF-α.

RESULTS

IL-6 was expressed in 13 (76%) patients with biopsy-positive GCA, 0 patients in biopsy-negative GCA, and 1(5%) patient with biopsy-negative without arteritis (p<0.05). OPN was expressed in 17 (100%) patients with biopsy-positive GCA, 2 (12%) patients with biopsy-negative GCA, and 0 patients with biopsy-negative without arteritis (p<0.05). Cox-2 was expressed in 16 (94%) patients with biopsy-positive GCA, 0 patients with biopsy-negative GCA, and 3 (15%) patients with biopsy-negative without arteritis (p<0.05). TNF- α was expressed in 17 (100%) patients with biopsy-positive GCA, 14 (82%) patients with biopsy-negative GCA, and 8 (40%) patients with biopsy-negative without arteritis (p<0.05).

CONCLUSIONS

IL-6, COX-2 and OPN are significantly more expressed in the presence of a positive TAB compared to a negative TAB. TNF-α is significantly more expressed in GCA patients compared to non-GCA patients. Thus, TNF-α expression may suggest a diagnosis of GCA despite a negative TAB. Further larger studies are needed to confirm these findings.

Clinical significance of positive anti-neutrophil cytoplasmic antibodies without evidence of anti-neutrophil cytoplasmic antibodies-associated vasculitis

AIM

Anti-neutrophil cytoplasmic antibodies (ANCA) have a role in the diagnostic workup of ANCA-associated vasculitis. However, the clinical significance of positive ANCA in the absence of vasculitis is yet to be determined. Therefore, we sought to investigate the clinical spectrum and rate of patients with a positive ANCA without evidence of vasculitis.

METHODS

Retrospective analysis of patients positive for cytoplasmic ANCA (C-ANCA) and proteinase 3 (PR3) or P-ANCA and myeloperoxidase (MPO) between 2007 and 2016 in the Chaim Sheba Medical Center, Israel. The proportion of patients who had no evidence of vasculitis among all patients with a positive C-ANCA/PR3 or P-ANCA/MPO was calculated according to tertiles of enzyme-linked immunosorbent assay (ELISA) antibody levels.

RESULTS

Among 113 patients who tested positive for C-ANCA/PR3 or P-ANCA/MPO, 68 (60.1%) had no evidence of vasculitis. ELISA antibody titers were significantly higher among patients with vasculitis than those without (6.2 vs 3.2, for C-ANCA/PR3 and 5.4 vs 2.6 for P-ANCA/MPO, P < 0.05). The proportion of patients without vasculitis among all patients with a positive C-ANCA/PR3 and among all patients with a positive P-ANCA/MPO declined in parallel to the increases in ELISA antibody level tertiles (96%, 57% and 22% in the 1st, 2nd and highest tertiles, respectively, for patients with C-ANCA/PR3 patients and 100%, 66% and 20% in the 1st, 2nd and highest tertiles, respectively, for patients with P-ANCA/MPO).

CONCLUSION

A significant proportion of patients with a positive C-ANCA/PR3 or P-ANCA/MPO do not have evidence of vasculitis, particularly those with low-medium ELISA antibody titers. Using a higher threshold of ANCA titers may be required to improve specificity.

The prevalence and clinical effect of immunogenicity of TNF-α blockers in patients with axial spondyloarthritis

OBJECTIVES

To evaluate the prevalence of immunogenicity of TNF-α blockers in axial spondyloarthritis (SpA) patients and to assess the effect of immunogenicity on drug levels and clinical response.

METHPDS

Patients with axial SpA treated with either infliximab (INF), adalimumab (ADA) or etanercept (ETN) were recruited to our observational cross-sectional study. Demographic and clinical data were collected and disease activity scores were assessed. Drug trough levels and anti-drug antibodies were measured in serum samples and collected before the next administration.

RESULTS

Thirty-nine patients with axial SpA with a mean age of 46.3±12.7 (10 women) were recruited to the study (14 receiving INF, 16 ADA and 9 ETN). Patients' mean therapy duration was 50.6 months (±46.4) and 6 (15%) of them were using MTX concomitantly with the TNF-α blockers. Anti-drug antibodies were found in 6 (15%) patients (4 with INF and 2 with ADA), all of which had undetectable drug level. No anti-drug antibodies were detected in patients treated with ETN. Immunogenicity was associated with higher BASDAI (Bath Ankylosing Spondylitis Disease Index), ASDAS-CRP (Ankylosing Spondylitis Disease Activity Score) and ASDAS-ESR.

CONCLUSIONS

Axial SpA patients failure to respond to TNF-α blockers may be at least partially related to immunogenicity. Measurement of anti-drug antibodies and drug levels in these patients may assist in determining further treatment strategies.

Risk factors for severe cranial ischaemic events in patients with giant cell arteritis

OBJECTIVES

Cranial ischaemic events constitute a significant component in the clinical spectrum of giant cell arteritis (GCA). Our aim was to investigate whether cardiovascular risk factors, specific medications and baseline clinical features are associated with the development of severe cranial ischaemic events in GCA patients.

METHODS

Retrospective analysis of GCA patients. Information collected included baseline clinical and laboratory data, comorbidities, cardiovascular risk factors and medications. GCA Patients with and without severe cranial ischaemic complications were compared.

RESULTS

A total of 83 patients with GCA were included in the study. Among them, 24 (29%) patients developed severe cranial ischaemic events. Compared with patients without severe cranial ischaemic events, those with severe cranial ischaemic events had lower erythrocyte sedimentation rate (ESR) levels at diagnosis (81±17 vs. 93±21, p=0.018) and were more likely to have jaw claudication (37.5% vs. 17%, p=0.043). Rate of cardiovascular risk factors and rate of use of anti-platelets and statins were similar between the two groups. The use of β-blockers was higher among patients with severe ischaemic events (46% vs. 20%, p=0.019). Logistic regression analysis showed that lower ESR levels (OR=0.967, 95% CI, 0.94, 0.99) and β-blockers use (OR=4.35, 95% CI, 1.33, 14.2) predicted development of severe cranial ischaemic complications.

CONCLUSIONS

The present study demonstrated that GCA patients with severe cranial ischaemic events had lower inflammatory responses and were more likely to have been treated with β-blockers. Cardiovascular risk factors and antiplatelet therapy had no effect on the occurrence of severe cranial ischaemic events.

Association between specimen length and diagnostic yield of temporal artery biopsy

OBJECTIVES

Temporal artery biopsy (TAB) is performed in patients suspected of giant cell arteritis (GCA). Inadequate TAB specimen length is considered a possible explanation for a negative biopsy in patients with GCA. We investigated the association between specimen length and diagnostic yield of TAB.

METHOD

We conducted a retrospective analysis of 240 patients who underwent TAB in a single hospital between 2000 and 2015. Patients were diagnosed with GCA based on positive TAB or, when TAB was negative, on clinical grounds that fulfilled the American College of Rheumatology (ACR) 1990 criteria. Baseline clinical and laboratory features and TAB length were obtained from medical records. Among patients diagnosed with GCA, the rate of TAB positivity was calculated according to biopsy length (< 5, 5-9, 10-14, and ≥ 20 mm).

RESULTS

Out of 240 patients, 88 were diagnosed with GCA: 62 had a positive TAB and 26 were diagnosed based on clinical grounds despite a negative TAB. Among those who were diagnosed with GCA, the length of the TAB specimen was similar in those with a positive and a negative TAB (1.13 ± 1.68 mm vs. 1.15 ± 0.61 mm, respectively, p = 0.928). The TAB positivity rate was similar among all ranges of biopsy length [< 5 mm: 7/10 (70%); 5-9 mm: 22/31 (71%); 10-14 mm: 11/16 (69%); 15-19 mm: 11/16 (69%); ≥ 20 mm: 11/15 (73%, p = ns] and was similar to the overall biopsy positivity rate.

CONCLUSIONS

Specimen length is not associated with diagnostic yield of TAB.

Factors associated with suitability of empiric antibiotic therapy in hospitalized patients with bloodstream infections

BACKGROUND

Bacteremia is associated with high morbidity and mortality rates. Initiation of inadequate empiric antibiotic therapy is associated with a worse outcome. The aim of this study was to establish the prevalence and the factors associated with inappropriate empiric antibiotic therapy in patients hospitalized with bacteremia.

METHODS

A cross-sectional study was conducted during January 2010-December 2011 at the medical wards of the Chaim Sheba Medical Center, Israel. The records of all patients with bacteremia were reviewed. Clinical and laboratory characteristics, bacteremic pathogens and antimicrobial agents were retrieved from the medical records. Factors associated with appropriateness of empiric antibiotic therapy were assessed.

RESULTS

A total of 681 eligible adults were included in the study. Antibiotic therapy was found to be inappropriate in 138 (20.2%) patients (95% C.I. 17.2-23.2). The rate of appropriateness was not related to the type of antibiotic regimen and the type of bacteria. Patients with healthcare-associated infections were more likely to be administrated inappropriate antibiotic therapy. Patients with primary bloodstream infections were also more likely to be administrated inappropriate antibiotic therapy. Empiric combination therapy was more likely to be appropriate than monotherapy, except for an aminoglycosides-based combination.

CONCLUSIONS

Combination empiric antibiotic therapy should be considered in patients with healthcare-associated infections and in those with primary bloodstream infections.

The association between normal-range admission potassium levels in Israeli patients with acute coronary syndrome and early and late outcomes

Abnormal serum potassium levels are associated with an increased risk of ventricular arrhythmias and mortality in patients with acute myocardial infarction (AMI). The aim of the present study was to evaluate whether different levels of serum potassium, within the normal range, are associated with worse outcomes. The present study comprised 1277 patients with AMI and normal-range admission potassium levels (3.5-5.2 mEq/L), who were enrolled and prospectively followed up in the Acute Coronary Syndrome Israeli Survey between 2010 and 2013. Patients were divided into 4 quartiles based on admission potassium levels; "normal-low" (K ≥ 3.5 and K ≤ 3.9), "normal-moderate" (K > 3.9 and K ≤ 4.18), "normal-high" (K > 4.18 and K ≤ 4.45), and "normal-very high" (K > 4.45 and K ≤ 5.2). We analyzed the association between admission serum potassium levels and 7 days in-hospital complication rates, and 30-day and 1-year all-cause mortality rates. Patients with "normal-very high" potassium displayed increased frequency of baseline clinical risk factors and experienced a higher rate of acute kidney injury during hospitalization compared with the "normal-low" group (7.7% vs 2.4%; P = 0.002). However, the rate of in-hospital ventricular arrhythmias was similar across the range of admission potassium levels (overall P = 0.26), Multivariate analysis showed that compared with "low-normal" potassium values, patients with "normal-very high" potassium levels experienced increased risk for 30-days (adjusted hazard ratio 2.88, 95% confidence interval 1.05-7.87, P = 0.039) and 1-year all-cause mortality (adjusted hazard ratio 1.98, 95% confidence interval 1.05-3.75, P = 0.034). In patients admitted with AMI, admission serum potassium levels of 4.45 to 5.2 mEq/L are not associated with in-hospital ventricular arrhythmias, but are associated with increased short and long-term mortality.

COP9-Signalosome deneddylase activity is enhanced by simultaneous neddylation: insights into the regulation of an enzymatic protein complex

Background

Cullin-RING ubiquitin ligases (CRLs) are regulated by neddylation, which is a post translation modification of the Cullin family proteins. Neddylation of Cul1 activates the ligase through some means of biochemical mechanisms. The rate of neddylation and its extent are regulated by 2 opposing enzymatic processes: neddylation by an enzymatic cascade, and deneddylation by COP9-Signalosome (CSN) complex protein. The mechanism by which COP9-Signalosome catalytic activity is regulated is not well understood.

Methods

We set an in vitro neddylation and deneddylation reaction using as a source for specific COP9/Signalosome deneddylase activity either Hela cells extract or purified Signalosome. Neddylation reaction of either endogenic Cul1 from Hela cells extract or recombinant Cul1 was catalyzed by recombinant neddylation enzymes. Deneddylation rate was tested either simultaneous to neddylation or after termination of neddylation by using an ATP depleting reaction or by directly inhibiting the neddylation activation enzyme named APP-BP1/UBA3 by its specific inhibitor MLN-4924.

Results

We demonstrated that neddylation and deneddylation are catalytically engaged and that inhibition of Cul1 neddylation significantly causes a decline in the rate of COP9-Signalosome deneddylase activity. Since neddylation is an ATP consuming reaction we managed to isolate the 2 opposing processes which surprisingly caused a decline in COP9 activity. Using MLN-4924 we demonstrated that direct inhibition of neddylation negatively influences the rate of deneddylation. The hypothesis that phosphorylation controls deneddylation was ruled out by the fact that no change in the rate of deneddylation was exemplified while converting the use of ATP with AMP-PNP.

Conclusions

We demonstrated that deneddylation of Cul1 is positively regulated through direct simultaneous neddylation and is not dependent upon autophosphorylation. Defining the mechanism that regulates neddylation and deneddylation of Cullin proteins is important due to their effect on highly conserved cellular processes. We showed that minor changes in the degree of Cul1 neddylation linearly control the degree of p27 conjugation to ubiquitin, which emphasizes the hypothetic physiologic significance of our findings.

Electronic supplementary material

The online version of this article (doi:10.1186/s13008-015-0011-0) contains supplementary material, which is available to authorized users.

Is temporal artery biopsy essential in all cases of suspected giant cell arteritis?

OBJECTIVES

Temporal artery biopsy (TAB) is performed in cases of suspected giant cell arteritis (GCA), and is the gold-standard for diagnosis of the disease. Current American College of Rheumatology (ACR) classification criteria may aid in the diagnosis of GCA. We aimed to assess whether TAB is essential in all cases of suspected GCA, or whether ACR criteria can replace the need for this procedure in some cases.

METHODS

Retrospective analysis of 216 patients who underwent TAB in a single hospital between 2000 and 2013. Pre-TAB and post-TAB ACR criteria were calculated. Sensitivity and specificity of ACR criteria for the diagnosis of GCA were assessed.

RESULTS

Overall, 55 patients had histological evidence of GCA.Out of 161 patients with negative TAB findings, 34 were diagnosed with GCA, and 127 were not diagnosed with GCA. Sensitivity of TAB for the diagnosis of GCA was 61.7%. Sensitivity and specificity of ACR criteria for diagnosis of GCA before performing TAB were 68.5% and 58%, respectively. Sensitivity and specificity of ACR criteria after performing TAB biopsy were 89.8% and 64.5%, respectively.

CONCLUSIONS

Temporal artery biopsy should be performed in the majority of patients with suspected GCA, and may be obviated only in patients with a pre-TAB ACR score of ≤ 1. In all other cases, when GCA is suspected, ACR criteria should not be a substitute to TAB, as they are not highly specific.

Diabetes mellitus with normal renal function is associated with anaemia

BACKGROUND

Anaemia is a common complication of diabetes mellitus (DM), usually related to renal failure. There is scarce information as to the levels of haemoglobin (Hb) and the rate of anaemia in diabetic patients with normal renal function. We, therefore, evaluated haemoglobin levels and the rate of anaemia in diabetic subjects with normal renal functions [estimated glomerular filtration rate (eGFR) > 60 mL/min].

METHODS

The charts of 9250 subjects who attended the Institute of Periodic Medical Examinations at the Chaim Sheba Medical Center for a routine yearly check-up were reviewed. Four hundred and forty-five subjects with type 2 DM and normal renal function were indentified and compared with those without DM who were routinely examined at the same time. Subjects' electronic records were used to build a biochemical and clinical database.

RESULTS

Mean haemoglobin levels were lower in subjects with DM than in those without (14.2 vs. 14.7 g/dL, respectively; p < 0.001). Anaemia was observed in 48 (10.8%) subjects in the diabetic group and in only 12 (2.7%) in the nondiabetic group (p < 0.001). Multivariate analysis revealed that age, gender, history of gastrointestinal disease, use of beta blockers, renal function and DM were independent determinants of haemoglobin levels. After adjustment for age, gender, history of gastrointestinal tract diseases and renal function, DM remained a significant determinant of anaemia with an odds ratio of 2.15 (confidence interval: 1.07-4.31).

CONCLUSIONS

Anaemia is more common in diabetic patients even when eGFR > 60 mL/min.

Serum uric acid is associated with coronary artery calcification

Uric acid (UA) is associated with atherosclerosis, and coronary artery calcium (CAC) is a marker of atherosclerosis. The authors studied the association between UA and CAC. A total of 663 asymptomatic patients (564 men; mean age, 55±7 years) were evaluated for the presence of CAC. The study population was divided into three tertiles according to their UA levels, and the prevalence of CAC was compared between the tertiles. CAC was detected in 349 (53%) patients. Levels of UA were significantly higher in those with CAC than in those without CAC (5.6+1.2 vs 5.3+1.3; P=.003). The odds ratio for the presence of CAC in the highest vs lowest UA tertile was 1.72 (95% confidence interval, 1.17-2.51). The highest UA tertile remained associated with the presence of CAC after adjustment for known cardiovascular risk factors. The results show that high serum UA levels are associated with the presence of CAC.

Individual differences in allocation of funds in the dictator game associated with length of the arginine vasopressin 1a receptor RS3 promoter region and correlation between RS3 length and hippocampal mRNA

Human altruism is a widespread phenomenon that puzzled evolutionary biologists since Darwin. Economic games illustrate human altruism by showing that behavior deviates from economic predictions of profit maximization. A game that most plainly shows this altruistic tendency is the Dictator Game. We hypothesized that human altruistic behavior is to some extent hardwired and that a likely candidate that may contribute to individual differences in altruistic behavior is the arginine vasopressin 1a (AVPR1a) receptor that in some mammals such as the vole has a profound impact on affiliative behaviors. In the current investigation, 203 male and female university students played an online version of the Dictator Game, for real money payoffs. All subjects and their parents were genotyped for AVPR1a RS1 and RS3 promoter-region repeat polymorphisms. Parents did not participate in online game playing. As variation in the length of a repetitive element in the vole AVPR1a promoter region is associated with differences in social behavior, we examined the relationship between RS1 and RS3 repeat length (base pairs) and allocation sums. Participants with short versions (308-325 bp) of the AVPR1a RS3 repeat allocated significantly (likelihood ratio = 14.75, P = 0.001, df = 2) fewer shekels to the 'other' than participants with long versions (327-343 bp). We also implemented a family-based association test, UNPHASED, to confirm and validate the correlation between the AVPR1a RS3 repeat and monetary allocations in the dictator game. Dictator game allocations were significantly associated with the RS3 repeat (global P value: likelihood ratio chi(2) = 11.73, df = 4, P = 0.019). The association between the AVPR1a RS3 repeat and altruism was also confirmed using two self-report scales (the Bardi-Schwartz Universalism and Benevolence Value-expressive Behavior scales). RS3 long alleles were associated with higher scores on both measures. Finally, long AVPR1a RS3 repeats were associated with higher AVPR1a human post-mortem hippocampal messenger RNA levels than short RS3 repeats (one-way analysis of variance (ANOVA): F = 15.04, P = 0.001, df = 14) suggesting a functional molecular genetic basis for the observation that participants with the long RS3 repeats allocate more money than participants with the short repeats. This is the first investigation showing that a common human polymorphism, with antecedents in lower mammals, contributes to decision making in an economic game. The finding that the same gene contributing to social bonding in lower animals also appears to operate similarly in human behavior suggests a common evolutionary mechanism.

Regulation of neddylation and deneddylation of cullin1 in SCFSkp2 ubiquitin ligase by F-box protein and substrate

The activity of cullin-containing ubiquitin protein ligase complexes is stimulated by linkage to cullin of the ubiquitin-like protein Nedd8 ("neddylation"). Neddylation is inhibited by the tight binding of cullins to CAND1 (cullin-associated and neddylation-dissociated 1) protein, and Nedd8 is removed from cullins by specific isopeptidase activity of the COP9/signalosome (CSN) complex. The mechanisms that regulate neddylation and deneddylation of cullins were unknown. We examined this problem for the case of SCF(Skp2), a cullin1 (Cul1)-containing ubiquitin ligase complex that contains the S phase-associated protein Skp2 as the substrate-binding F-box protein subunit. SCF(Skp2) targets for degradation the cyclin-dependent kinase (cdk) inhibitor p27 in the G(1)-to-S phase transition, a process that requires its phosphorylation and binding to cdk2-cyclin E. Because levels of Skp2, cyclin E, and the accessory protein Cks1 (cyclin kinase subunit 1) all rise at the end of G(1) phase, it seemed possible that the neddylation of Cul1 in SCF(Skp2) is regulated by the availability of the F-box protein and/or the substrate. We found that the supplementation of Skp2-Skp1 and substrate (along with further components necessary for substrate presentation to the ubiquitin ligase) to extracts of HeLa cells synergistically increased levels of neddylated Cul1. Skp2-Skp1 abrogates the inhibitory influence of CAND1 on the neddylation of Cul1 by promoting the dissociation of the cullin-CAND1 complex, whereas substrate, together with substrate-presenting components, prevents the action of CSN to deneddylate cullin. We propose a sequence of events in which the increased availability of Skp2 and substrate in the transition of cells to S phase promotes the neddylation and assembly of the SCF(Skp2) ubiquitin ligase complex.

Role of the SCFSkp2 ubiquitin ligase in the degradation of p21Cip1 in S phase

The cyclin-dependent kinase inhibitor p21Cip1 has important roles in the control of cell proliferation, differentiation, senescence, and apoptosis. It has been observed that p21 is a highly unstable protein, but the mechanisms of its degradation remained unknown. We show here that p21 is a good substrate for an SCF (Skp1-Cullin1-F-box protein) ubiquitin ligase complex, which contains the F-box protein Skp2 (S phase kinase-associated protein 2) and the accessory protein Cks1 (cyclin kinase subunit 1). A similar ubiquitin ligase complex has been previously shown to be involved in the degradation of a related cyclin-dependent kinase inhibitor, p27Kip1. The levels of Skp2 oscillate in the cell cycle, reaching a maximum in S phase. The ubiquitylation of p21 in vitro required the supplementation of all components of the SCF complex as well as of Cks1 and Cdk2-cyclin E. The protein kinase Cdk2-cyclin E acts both by the phosphorylation of p21 on Ser-130 and by the formation of a complex with p21, which is required for its presentation to the ubiquitin ligase. As opposed to the case of p27, the phosphorylation of p21 stimulates its ubiquitylation but is not absolutely required for this process. Levels of p21 are higher in Skp2-/- mouse embryo fibroblasts than in wild-type fibroblasts in the S phase, and the rates of the degradation of p21 are slower in cells that lack Skp2. It is suggested that SCFSkp2 participates in the degradation of p21 in the S phase.

Concurrent substance use and outcome in combined behavioral and naltrexone therapy for opiate dependence

The effect of concurrent nonopiate drug use on outcome of treatment for opiate dependence.

METHOD

Forty-seven opiate-dependent patients received a 6-month course of outpatient treatment with naltrexone and cognitive-behavioral therapy (behavioral naltrexone therapy, BNT) at a university-based research clinic. Opiate-negative urines and naltrexone ingestion were rewarded with monetary vouchers. Abstinence from other drugs was encouraged verbally, but no contingencies were placed on nonopiate drug use. The proportions of all urines (collected twice weekly) positive for cocaine, cannabis, and benzodiazepines over the course of treatment were evaluated as predictors of outcome of opiate dependence treatment, as measured by proportion of opiate-positive urines, days retained in treatment, and proportion of naltrexone doses taken, using Pearson product moment correlations and one-way analysis of variance (ANOVA).

RESULTS

The majority of patients (78%) used a nonopiate drug at least once during the trial. There were no significant correlations between concurrent drug use measures and opiate dependence treatment outcomes, indicating no simple linear relationship between these measures. However, when concurrent drug use was trichotomized into abstinent, intermittent, and heavy use groups, groups with intermittent use had superior outcome compared to both abstinent and heavy use groups in several contrasts.

CONCLUSIONS

Intermittent use of nonopiate drugs is common during outpatient treatment for opiate dependence and may be a favorable prognostic indicator. This may support a "harm reduction" approach as opposed to a strict abstinence-oriented approach. Further research is needed to identify the optimal therapeutic stance toward other drug use during treatment for opiate dependence.

Inverse relation between levels of p27(Kip1) and of its ubiquitin ligase subunit Skp2 in colorectal carcinomas

BACKGROUND

Previous studies have shown that low levels of p27(Kip1), an inhibitor of G1 cyclin-dependent kinases, are associated with high aggressiveness and poor prognosis in a variety of cancers. Decreased levels of p27 are caused, at least in part, by acceleration of the rate of its ubiquitin-mediated degradation. In cultured cells and cell-free biochemical systems, it has been shown that p27 is targeted for degradation by a ubiquitin ligase complex that contains Skp2 (S-phase kinase-associated protein 2) as the specific substrate-recognizing and rate-limiting subunit. This investigation was undertaken to examine the possible relation between levels of p27 and of its specific ubiquitin ligase subunit Skp2 in human cancers.

METHODS

Quick-frozen colorectal tumor samples from 20 patients were homogenized at 0 degrees C in buffer containing a mixture of protease inhibitors. Samples were separated by electrophoresis on sodium dodecyl sulfate-polyacrylamide gels, transferred to nitrocellulose, and probed with highly specific monoclonal antibodies directed against Skp2 and p27. The expression of Skp2 also was examined by immunohistochemistry using formalin fixed, paraffin embedded tissue sections from the same cases.

RESULTS

A strongly significant inverse correlation was found between levels of Skp2 and p27 (r = -0.812; P < 0.0001). Thus, decreased levels of p27 were associated with strongly increased levels of Skp2, whereas high levels of p27 coincided with low levels of Skp2. Immunohistochemical examination of Skp2 expression agreed with immunoblot analysis in 89% of cases.

CONCLUSIONS

The results are compatible with the notion that increased expression of Skp2 may have a causative role in decreasing the levels of p27 in aggressive colorectal carcinomas.

Inverse relation between levels of p27(Kip1) and of its ubiquitin ligase subunit Skp2 in colorectal carcinomas

BACKGROUND

Previous studies have shown that low levels of p27(Kip1), an inhibitor of G1 cyclin-dependent kinases, are associated with high aggressiveness and poor prognosis in a variety of cancers. Decreased levels of p27 are caused, at least in part, by acceleration of the rate of its ubiquitin-mediated degradation. In cultured cells and cell-free biochemical systems, it has been shown that p27 is targeted for degradation by a ubiquitin ligase complex that contains Skp2 (S-phase kinase-associated protein 2) as the specific substrate-recognizing and rate-limiting subunit. This investigation was undertaken to examine the possible relation between levels of p27 and of its specific ubiquitin ligase subunit Skp2 in human cancers.

METHODS

Quick-frozen colorectal tumor samples from 20 patients were homogenized at 0 degrees C in buffer containing a mixture of protease inhibitors. Samples were separated by electrophoresis on sodium dodecyl sulfate-polyacrylamide gels, transferred to nitrocellulose, and probed with highly specific monoclonal antibodies directed against Skp2 and p27. The expression of Skp2 also was examined by immunohistochemistry using formalin fixed, paraffin embedded tissue sections from the same cases.

RESULTS

A strongly significant inverse correlation was found between levels of Skp2 and p27 (r = -0.812; P < 0.0001). Thus, decreased levels of p27 were associated with strongly increased levels of Skp2, whereas high levels of p27 coincided with low levels of Skp2. Immunohistochemical examination of Skp2 expression agreed with immunoblot analysis in 89% of cases.

CONCLUSIONS

The results are compatible with the notion that increased expression of Skp2 may have a causative role in decreasing the levels of p27 in aggressive colorectal carcinomas.

The cell-cycle regulatory protein Cks1 is required for SCF(Skp2)-mediated ubiquitinylation of p27

The cyclin-dependent kinase (CDK) inhibitor p27 is degraded in late G1 phase by the ubiquitin pathway, allowing CDK activity to drive cells into S phase. Ubiquitinylation of p27 requires its phosphorylation at Thr 187 (refs 3, 4) and subsequent recognition by S-phase kinase associated protein 2 (Skp2; refs 5-8), a member of the F-box family of proteins that associates with Skp1, Cul-1 and ROC1/Rbx1 to form an SCF ubiquitin ligase complex. However, in vitro ligation of p27 to ubiquitin could not be reconstituted by known purified components of the SCFSkp2 complex. Here we show that the missing factor is CDK subunit 1 (Cks1), which belongs to the highly conserved Suc1/Cks family of proteins that bind to some CDKs and phosphorylated proteins and are essential for cell-cycle progression. Human Cks1, but not other members of the family, reconstitutes ubiquitin ligation of p27 in a completely purified system, binds to Skp2 and greatly increases binding of T187-phosphorylated p27 to Skp2. Our results represent the first evidence that an SCF complex requires an accessory protein for activity as well as for binding to its phosphorylated substrate.