Could reasons for admission help to screen unhealthy alcohol use in emergency departments? A multicenter French study

Background

Many patients admitted to general emergency departments (EDs) have a pattern of drinking that could lead to future alcohol-related complications. However, it is often difficult to screen these patients in the context of emergency. The aim of this study is to analyze whether reasons for admission could help to screen patients who have an unhealthy alcohol use.

Method

Patients were recruited among six public hospital ED in France, between 2012 and 2014. During a one-month period in each hospital, anonymous questionnaires including sociodemographic questions, AUDIT-C and RAPS4-QF were administered to each patients visiting the ED. The reason for admission of each patient was noted at the end of their questionnaire by the ED practitioner.

Results

Ten thousand Four hundred twenty-one patients were included in the analysis. Patients who came to the ED for injuries and mental disorders were more likely to report unhealthy alcohol use than non-harmful use or no use. Among male patients under 65 years old admitted to the ED for a mental disorder, 24.2% drank more than four drinks (40 g ethanol) in typical day at least four time a week in the last 12 months. Among these patients, 79.7% reported daily or almost daily heavy episodic drinking (HED, 60 g ethanol), and all were positive on the RAPS4-QF.

Conclusion

This study highlights that unhealthy alcohol use is frequent among ED patients and particularly among those who come for injuries or mental disorders. Men under 65 years old with a mental disorder require special attention because of their increased prevalence of daily or almost daily HED.

Observational, Retrospective Evaluation of a New Nurse-Initiated Emergency Department Pain Management Protocol

BACKGROUND

Triage nurses are important in pain management and in early relief of pain among patients admitted to the emergency department (ED).

AIMS

To assess a new nurse-initiated pain management protocol, without the requirement for medical prescription, wich was implemented in October 2016 for patients with moderate or severe pain in the ED. It allows the administration of oral acetaminophen and oral oxycodone chlorydrate during the first evaluation of the patient by a nurse and eliminates the use of codeine or tramadol.

METHODS

We conducted a comparative, single-center, retrospective study that looked at the outcomes of a new nursing protocol for patients aged ≥16 years with moderate to severe pain. The primary outcome was the percentage of increase of analgesics delivered by the nurse.

RESULTS

A total of 756 patients were included: 377 before and 379 after protocol implementation. Oral analgesic use on admission increased from 44.3% to 57.8% (p < .001), and from 50.2% to 76.6% among patients with severe pain (p < .001). Strong opioid analgesic administration increased from 2.1% to 41.2%. This increase was also observed among those with moderate pain (1.4% to 13.3%; p < .001) and those with severe pain (2.6% to 62.6%; p < .001). Analgesic prescriptions added by the clinician decreased from 28.6% to 21.4% (p = .028).

CONCLUSIONS

We observed an increase in analgesic administration after the implementation of a new nurse-initiated pain treatment protocol, especially an increase in oral opioid analgesics, for patients with moderate to severe pain.

Effectiveness of two intranasal vaccines for the control of bovine respiratory disease in newborn beef calves: A randomized non-inferiority multicentre field trial

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Multicentre field trials with natural pathogen exposure complement challenge trials.

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Beef calves housed with their dams were assessed for bovine respiratory disease (BRD).

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Two commercial intranasal live vaccines for BRSV-bPI3V were evaluated.

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New Vaccine A demonstrated non-inferiority compared to benchmarked Vaccine B.

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Difference in BRD prevalence between Vaccines A and B was −0.4% (95% CI −1.6 to 0.8%).

Bovine respiratory syncytial virus (BRSV) and bovine parainfluenza-3 virus (bPI3V) are major causes of bovine respiratory disease (BRD) in newborn calves worldwide. Vaccination is widely used to prevent BRD, and intranasal vaccines for BRSV and bPI3V were developed to overcome interference from BRSV and bPI3V-specific maternally derived antibodies. Many experimental challenge trials have demonstrated that intranasal vaccines for BRSV and bPI3V are efficacious, but effectiveness under field conditions has been demonstrated less often, especially for newborn beef calves. The objective of this field trial was to compare the effectiveness of a newly available commercial BRSV-bPI3V intranasal vaccine with that of a benchmarked one in newborn beef calves reared in a cow-calf system. A total of 935 calves from 39 farms were randomized into two vaccine groups (Bovalto Respi Intranasal [Vaccine A], n = 468; Rispoval RS + PI3 Intranasal [Vaccine B], n = 467), and monitored during the in-house risk period up to three months after vaccination. Non-inferiority analysis was performed by calculating the difference in BRD prevalence between the two vaccine groups.

No significant differences were observed between vaccines regarding clinical outcomes of morbidity, mortality, duration between vaccination and BRD occurrence, or treatments required. Because the upper limit of the 2-sided 95% confidence interval of the difference in BRD prevalence between the two treatment groups (0.8%) was less than the margin of non-inferiority (δ = 5%), a non-inferiority of Vaccine A was concluded. In conclusion, Vaccine A is at least as effective as Vaccine B for the prevention of BRD in newborn beef cattle in a cow-calf system under field conditions.

[Evaluation of the management of low-risk pulmonary embolism diagnosed in an emergency department. HoPE study (Home treatment of Pulmonary Embolism)]

INTRODUCTION

Risk stratification allows outpatient management of low-risk pulmonary embolism (PE). Here, we carry out an evaluation of the professional practices on the emergency management of low-risk PE, after selection with the sPESI score.

MATERIAL AND METHOD

All patients admitted to the emergency department of Chambéry hospital, with a final diagnosis of PE are analyzed. The PE of score sPESI at 0 are included, in the absence of contraindications. Ninety-day follow-up is done. The objective is to evaluate the proportion of ambulatory care for low-risk patients.

RESULTS

Eighty PE were diagnosed in 2016, 28 with sPESI score at 0 and 3 patients excluded. Of the 25 inclusions, 6 patients had signs of right ventricular dysfunction and were therefore hospitalized. The remaining 19 were eligible for outpatient care but only 8 of them stayed less than 24hours in the hospital.

DISCUSSION

The sPESI score is a decision support tool for outpatient management but should not be used alone. The search for right ventricular dysfunction seems important here.

Comparison between the WHO and NIAAA criteria for binge drinking on drinking features and alcohol-related aftermaths: Results from a cross-sectional study among eight emergency wards in France

BACKGROUND

Binge drinking (BD) consists of heavy episodic alcohol use. Whereas the World Health Organization (WHO) defines BD as 60g of alcohol or more per occasion, the National Institute on Alcoholism and Alcohol Abuse (NIAAA) conceives BD as drinking 70g (men) or 56g (women) in less than two hours. We compared the subjects delineated by each definition.

METHODS

Eight-center cross-sectional study among 11,695 subjects hospitalized in emergency wards. Participants completed the Alcohol Use Disorders Identification Test - Consumption (AUDIT-C), CAGE and Rapid Alcohol Problem Screen 4 (RAPS4-QF) questionnaires. The WHO criteria were investigated using the RAPS4-QF. Independent questions assessed the NIAAA criteria. The main medical admission motive was noted. The characteristics of subjects meeting respectively: 1) the exclusive WHO criteria (BD1); 2) the NIAAA criteria (BD2); and 3) no BD criteria (noBD) were compared using multinomial regression analyses. Binary age- and gender-adjusted regression analyses directly compared BD1 and BD2. Subjects with at least four drinking occasions per week were excluded from the analyses, to withdrawn regular heavy drinking.

RESULTS

Compared to BD1, BD2 subjects were more frequently males (OR=1.67 [1.39-2.0]), single (aOR=1.64 [1.36-1.98]) and unemployed (aOR=1.57 [1.27-1.90]). BD2 reported significantly more drinks per occasion, and higher heavy drinking frequencies. Previous alcohol-related remarks from family (aOR=3.00 [2.53-3.56]), ever drinking on waking-up (aOR=2.05 [1.37-2.72]), and admission for psychiatric motive (aOR=2.27 [1.68-3.07]) were more frequent among BD2 subjects.

CONCLUSIONS

Compared to WHO criteria, NIAAA criteria for BD delineate subjects with more concerning drinking patterns and alcohol aftermaths.

[Outpatient management of pulmonary embolism diagnosed in emergency services]

In the emergency department, the management of patients with pulmonary embolism depends on the early mortality risk. Outpatient care is possible in low-risk patients. We present the existing scores and the strategy proposed by the North Alps Emergency Network, which uses the simplified PESI score (Pulmonary Embolism Severity Index) to select those low-risk patients, candidates for early discharge.

Infection risk prevention following total knee arthroplasty

INTRODUCTION

Implant infection is serious; prevention is mandatory, and requires assessment.The present study assessed the incidence of deep surgical-site infection (SSI) at 1 year following total knee arthroplasty (TKA) and adherence to skin preparation, antibiotic prophylaxis,screening and prevention in case of methicillin-resistant S. aureus (MRSA).

HYPOTHESIS

Adherence to prevention measures reduces infection risk secondary to TKA.

MATERIAL AND METHODS

A prospective study of the incidence of SSI following primary TKA was run from December 1st 2005 to December 31st 2006 in a continuous series of 364 operations in 359 patients, excluding cases of septic or aseptic revision. Each implant was followed up for 12 months. Adherence to practice was assessed by independent observers. Antibiotic prophylaxis was assessed; skin preparation was scored (out of 10); MRSA was systematically screened for, and preventive measures were assessed in positive cases. Median follow-up was 12 months.Patients with less than 11 months' FU were contacted by telephone. Median age was 72 years(range, 45-92 years). Eighty-seven percent of patients had ASA scores of 2; 14% were diabetic,and 42% obese. Mean surgery time was 70 min (range, 30-164 min). Among the implants, 81.5% were cemented. Eighty-six percent of operations had NNIS scores of 0. Infection risk linked to theater environment and teams was under control.

RESULTS

Fourteen patients were lost to follow-up and excluded from analysis. The incidence of infection was 1.4% (n = 5/350) (95% CI [0.41-3.22]). Three of the infections were early (</-1 month), and two were polymicrobial. Antibiotic prophylaxis was implemented correctly in 99% of cases, with skin preparation scores of 8.75 in 61% of cases and of 10 in 39%. Among the patients, 2.5% were MRSA-positive, none of whom developed infection. Infection prevention measures were applied in only half of the MRSA-positive cases. No MRSA-positive patients developed SSI.

DISCUSSION

SSI incidence in the present series was low, but certainly underestimated. Assessment found good implementation of infection prevention protocols, with SSI occurring randomly with regard to adherence parameters (antibiotic prophylaxis, skin preparation, MRSA status).

CONCLUSION

Our hypothesis could not be confirmed. The study was mandatory for a health-care institution, and indispensable from a legal standpoint.

LEVEL OF EVIDENCE

Level IV. Prospective prognostic study.

L-carnitine supplementation improves fatigue, mood and sleep in cancer patients with fatigue and carnitine deficiency

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Background: Carnitine is a natural aminoacid derivative that plays a crucial role in cellular energy metabolism. To determine the dose and tolerability we conducted a phase II study with increasing doses of L-carnitine supplementation. In a preliminary analysis, we reported that L-carnitine could improve fatigue, mood and sleep. (Cruciani et al., 2004). Analysis of the full dataset has confirmed and extended these findings. Methods: Patients had active cancer, fatigue and a Karnofsky ≥50. Carnitine deficiency was defined as free carnitine <35 μm]/L for males and <25 for females (normal range 35–67 and 25–55 respectively), or a ratio of acyl/free carnitine >0.4. We utilized a standard maximum tolerated dose (MTD) design, with 3 patients assigned to each successive dose group, starting at 250 mg/day and increasing in each group by 500 mg/day to a maximum dose target of 3000 mg/day. Fatigue (measured by the BFI), depressed mood (CES-D), quality of sleep (ESS), and performance status (Karnofsky), as well as carnitine serum levels were assessed at baseline and after one week of L-carnitine supplementation. Results: Seven groups of three patients each received L-carnitine supplementation for a week with 250, 750, 1,250, 1,750, 2,250, 2,750 or 3,000 mg/day. Of the 27 patients accrued 21 completed the study. Of these, 17 (mean (SD) age = 63.0 (18), females=8) showed an increase in serum L-carnitine levels. The median (min, max) total carnitine increased from 31 (21, 68) to 51 (29, 111) (p < 0.001) and the free carnitine increased from 25.0 (17, 48) to 39 (25, 82) (p < 0.001). The median (min, max) BFI score at baseline was 63 (36, 81) versus 39 (8, 82) after one week (p<0.001). There was also a significant dose response for BFI (r = -0.61, p = 0.01). Median (min, max) CES-D at baseline was 31. (4, 48) and 18.0 (0, 40) after one-week (p = 0.001). Median (min, max) ESS at baseline was 13.7 (2, 22) and 10.3 (1, 18) after one week (p=0.003). Median Karnofsky score did not change (pre and post = 70). Side effects were not observed in any of the groups. Conclusions: This study suggests that L-carnitine is safe up to 3,000 mg/day. Supplementation was associated with improvements in fatigue and depression scores. Fatigue improved in a dose dependent manner.

[Table: see text]

Happy together: the life and times of Ty retrotransposons and their hosts

The aim of this review is to describe the level of intimacy between Ty retrotransposons (Ty1-Ty5) and their host the yeast Saccharomyces cerevisiae. The effects of Ty location in the genome and of host proteins on the expression and mobility of Ty elements are highlighted. After a brief overview of Ty diversity and evolution, we describe the factors that dictate Ty target-site preference and the impact of targeting on Ty and adjacent gene expression. Studies on Ty3 and Ty5 have been especially informative in unraveling the role of host factors (Pol III machinery and silencing proteins, respectively) and integrase in controlling the specificity of integration. In contrast, not much is known regarding Ty1, Ty2 and Ty4, except that their insertion depends on the transcriptional competence of the adjacent Pol III gene and might be influenced by some chromatin components. This review also brings together recent findings on the regulation of Ty1 retrotransposition. A large number of host proteins (over 30) involved in a wide range of cellular processes controls either directly or indirectly Ty1 mobility, primarily at post-transcriptional steps. We focus on several genes for which more detailed analyses have permitted the elaboration of regulatory models. In addition, this review describes new data revealing that repression of Ty1 mobility also involves two forms of copy number control that act at both the trancriptional and post-transcriptional levels. Since S. cerevisiae lacks the conserved pathways for copy number control via transcriptional and post-transcriptional gene silencing found in other eukaryotes, Ty1 copy number control must be via another mechanism whose features are outlined. Ty1 response to stress also implicates activation at both transcriptional and postranscriptional steps of Ty1. Finally, we provide several insights in the role of Ty elements in chromosome evolution and yeast adaptation and discuss the factors that might limit Ty ectopic recombination.

l-Carnitine Supplementation for the Treatment of Fatigue and Depressed Mood in Cancer Patients with Carnitine Deficiency: A Preliminary Analysis

Nutritional factors are among the postulated causes of fatigue, a highly prevalent symptom in the cancer population, with serious impact on patients' quality of life. Deficiency of the micronutrient carnitine may play a role by reducing energy production through fatty acid oxidation. We present preliminary data of an open-label, dose-finding study to determine safety and maximally tolerated dose (MTD) of 1 week of L-carnitine supplementation in cancer patients with fatigue and carnitine deficiency. Patients who met inclusion/exclusion criteria underwent carnitine level determination. Eighty-three percent of these patients (15/18) had carnitine deficiency. Preliminary data analysis of 13 patients showed that total carnitine increased from 30.0 +/- 6.9 to 41.0 +/- 12.1 (mean +/- SD) after 1 week of supplementation (P = 0.01), and free carnitine increased from 24.3 +/- 6.1 to 33.8 +/- 9.8 (P = 0.004). Outcome measures were fatigue (BFI score), depression (CES-D), sleep disruption (ESS), and performance status (Karnofsky). Median (min, max) BFI score at baseline was 73 (46, 82) versus 50 (3, 82) after 1-week supplementation (P = 0.009). CES-D score at baseline was 29 (16, 42) and 22 (8, 32) after 1 week (P = 0.028). ESS at baseline was 46.5 (0, 69) and 30.4 (0, 72) after 1 week (P = 0.015). Karnofsky score did not change significantly (P = 0.38). We are currently conducting a randomized, double-blind, placebo-controlled study to rigorously assess the role of L-carnitine for the treatment of fatigue and depression in cancer patients.

Ethical challenges in the care of patients with serious illness

The approach to management of patients with advanced disease and serious illness has been strongly influenced by advances in science and technology, the increasing role of ethics in clinical practice, and the recognition of new rights and social changes. At the present time, decision making is modulated by ethical and legal considerations. One of the challenges of clinical practice is to maintain the delicate balance between the technical aspects and the humanistic aspects of care. For the resolution of this challenge, this article proposes an ethical and legal framework that considers the goals of care and respects the basic values of autonomy, beneficence, and justice. Ethical and legal principles complement sound medical practice but should never replace it. At all times, clarification of the medical situation, good communication, and information about state of the art treatment proposals are essential. In the context of advanced illness, the most prominent issues relate to decision making, justice, and research.

[Reproducibility of CT scan evaluation of muscular fatty degeneration. Intra- and interobserver analysis of 56 shoulders presenting with a ruptured rotator cuff muscles]

PURPOSE OF THE STUDY

This study was undertaken to determine the reproducibility of measurements of fatty degeneration of the rotator cuff using computed tomography (CT).

MATERIAL AND METHODS

Fifty-six patients who had undergone surgery for rotator cuff tear were included in this retrospective study. The extent of fatty infiltration was evaluated on CT scans with soft tissue windows in all 56 shoulders using a five-stage scoring system described by Goutallier. Five independent observers made the assessments. The same operation was repeated one month later to test intraobserver agreement. Four parameters were recorded: fatty infiltration of three muscles (supraspinatus, infraspinatus, subscapularis), and overall fatty infiltration grading. Interobserver variability was determined for each parameter using the intercorrelation coefficient (a test of reproducibility of quantitative measurements).

RESULTS

The most reproducible measurement was the overall fatty infiltration grade. For this parameter, interobserver agreement was good with an intercorrelation coefficient of 0.75. The interval of confidence was +/- 0.5. Intraobserver agreement depended on the observer's level of experience. It was good for overall fatty infiltration grade assess by three senior observers (r=0.78) and moderate for two junior observers.

CONCLUSION

The overall fatty infiltration grade is a reproducible parameter that should be used to evaluate the degree of fatty infiltration as the safety margin of this value (graded 0 to 4) is about 0.5. Fatty infiltration of a torn cuff would not be the only criterion to improve indications for treatment of rotator cuff tears.

Strains isogenic to S288C used in the yeast genome sequencing programme carry a functional KSS1 gene

In Saccharomyces cerevisiae, the KSS1 gene encodes the MAP kinase of the invasive/filamentous growth pathway. In addition to its role in this signal transduction pathway, Kssl can replace the Fus3 MAP kinase in the pheromone-response pathway, in the absence of FUS3. Previous work indicated that derivatives of the S288C strain carry a mutant kss1 allele. Here, we report evidence that S288C derivatives used in the Yeast Genome Sequencing Programme carry a functional KSS1 gene and can thus be used to study the regulation of gene expression by KSS1.

Activation of the Kss1 invasive-filamentous growth pathway induces Ty1 transcription and retrotransposition in Saccharomyces cerevisiae

Using a set of genomic TY1A-lacZ fusions, we show that Ste12 and Tec1, two transcription factors of the Kss1 mitogen-activated protein kinase (MAPK) cascade activate Ty1 transcription in Saccharomyces cerevisiae. This result strongly suggests that the invasive-filamentous pathway regulates Ty1 transcription. Since this pathway is active in diploid cells, we suspected that Ty1 transposition might occur in this cell type, despite the fact that this event has been never reported before (unless activated by heterologous promoters such as that of GAL1). We demonstrate here that constitutive activation of the invasive-filamentous pathway by the STE11-4 allele or by growth in low-nitrogen medium induces Ty1 transcription and retrotransposition in diploid cells. We show that Ty1 retrotransposition can be activated by STE11-4 in haploid cells as well. Our findings provide the first evidence that Ty1 retrotransposition can be activated by environmental signals that affect differentiation. Activation of the Kss1 MAPK cascade by stress is known to cause filament formation that permits the search for nutrients away from the colonization site. We propose that activation of Ty1 retrotransposition by this cascade could play a role in adaptive mutagenesis in response to stress.

Management of cancer pain

Patients with cancer have diverse symptoms, impairments in physical and psychological functioning, and other difficulties that can undermine their quality of life. If inadequately controlled, pain can have a profoundly adverse impact on the patient and his or her family. The critical importance of pain management as part of routine cancer care has been forcefully advanced by WHO, international and national professional organisations, and governmental agencies. The prevalence of chronic pain is about 30-50% among patients with cancer who are undergoing active treatment for a solid tumour and 70-90% among those with advanced disease. Prospective surveys indicate that as many as 90% of patients could attain adequate relief with simple drug therapies, but this success rate is not achieved in routine practice. Inadequate management of pain is the result of various issues that include: undertreatment by clinicians with insufficient knowledge of pain assessment and therapy; inappropriate concerns about opioid side-effects and addiction; a tendency to give lower priority to symptom control than to disease management; patients under-reporting of pain and non-compliance with therapy; and impediments to optimum analgesic therapy in the healthcare system. To improve the management of cancer pain, every practitioner involved in the care of these patients must ensure that his or her medical information is current and that patients receive appropriate education.

Trends in Cancer Pain Management

BACKGROUND: Pain is a prevalent symptom in cancer patients, affecting up to 50% of patients undergoing active cancer treatment and up to 90% of those with advanced disease. Although adequate relief can be achieved in the majority of cancer patients, pain is often treated inadequately in traditional settings. METHODS: The authors use their experience and that of others to review the evaluation and diagnosis of pain syndromes and the principles of management. RESULTS: The World Health Organization and other governmental agencies have recognized the importance of pain management as part of routine cancer care. Conducting a comprehensive assessment, competently providing analgesic drugs, and communicating with the patient and family allow effective management of pain in the cancer patient. CONCLUSIONS: Several approaches can promote adequate management of cancer pain, such as enhancing clinician knowledge of pain syndromes, improving pain assessment, and updating medical information related to pain and symptom control.

[Is surgical treatment of deltoid ligament rupture necessary in ankle fractures?]

PURPOSE OF THE STUDY

Fractures of the lateral malleolus associated with rupture of the deltoid ligament are severe fractures types. There is still discussion about wether the ruptured deltoid ligament should be sutured or not. To elucidate further the need for surgical repair of this structure a comparative and retrospective review was conducted at a mean follow-up of 4 years and 8 months.

MATERIAL AND METHODS

Twenty nine men and 15 women were included with a mean age of 34 years. Patients were subdivided into two groups according to the attitude regarding the ligament. In the first group (n = 18), an operative repair of the ligament was made and in the second group (n = 17) we leaved it unrepaired. Nine patients were evaluated separately because of an associated osteochondral fracture (n = 7) or a worse reduction of the fibula (n = 2). Subjective and objective clinical assessment were evaluated according to a modified Cedell classification. Roentgenograms including A.P, lateral, mortise view and a external rotation stress view described by Kleiger were obtained in all patients.

RESULTS

Subjective and objective analysis showed no significant difference between the two groups, likewise no differences were observed for post operative complications rate. Medial instability was observed in four cases (2 in group 1 and 2 in group II). Roentgenographicaly, more ossifications of the deltoid ligament were founded in group II (p = 0.013), and only one degenerative osteoarthritis of the ankle was seen in group II. Clinical results in the group of patients with osteochondral fracture were statistically worse than in the two previous groups (p = 0.001), with frequent progression to osteoarthritis in four cases.

DISCUSSION

In our experience it is impossible to advise surgical repair of the deltoid ligament in accordance to the type of lateral malleolar fracture like other authors have suggested. The existence of a significant widening of the medial space greater than 3 mm was nearly correlated with a deltoid ligament disruption, of the 23 patients treated with a medial approach, the ligament was ruptured in 22 cases. In this study, we may conclude than an untreated rupture of the deltoid ligament does not lead to instability. The advantages of the deltoid repair may be obtained if the fixation of the lateral malleolus allows a perfect congruency of the mortise. The most predictive radiographic factors for a poor outcome were a persistent widening of the medial joint greater than 3 mm, an associated osteochondral fracture and a poor reduction of the lateral malleolus which results in degenerative arthritis of the ankle at long term follow-up.

CONCLUSION

Repair of the deltoid ligament is unnecessary if the internal fixation of the fibula achieves an anatomical reconstitution of the mortise. Exploration of the medial side is indicated only with a medial incongruency greater than 3 mm on intra operative roentgenograms.

Yeast SNF1 protein kinase interacts with SIP4, a C6 zinc cluster transcriptional activator: a new role for SNF1 in the glucose response

The SNF1 protein kinase has been widely conserved in plants and mammals. In Saccharomyces cerevisiae, SNF1 is essential for expression of glucose-repressed genes in response to glucose deprivation. Previous studies supported a role for SNF1 in relieving transcriptional repression. Here, we report evidence that SNF1 modulates function of a transcriptional activator, SIP4, which was identified in a two-hybrid screen for interaction with SNF1. The N terminus of the predicted 96-kDa SIP4 protein is homologous to the DNA-binding domain of the GAL4 family of transcriptional activators, with a C6 zinc cluster adjacent to a coiled-coil motif The C terminus contains a leucine zipper motif and an acidic region. When bound to DNA, a LexA-SIP4 fusion activates transcription of a reporter gene. Transcriptional activation by SIP4 is regulated by glucose and depends on the SNF1 protein kinase. Moreover, SIP4 is differentially phosphorylated in response to glucose availability, and phosphorylation requires SNF1. These findings suggest that the SNF1 kinase interacts with a transcriptional activator to modulate its activity and provide the first direct evidence for a role of SNF1 in activating transcription in response to glucose limitation.

The yeast BDF1 gene encodes a transcription factor involved in the expression of a broad class of genes including snRNAs

While screening for genes that affect the synthesis of yeast snRNPs, we identified a thermosensitive mutant that abolishes the production of a reporter snRNA at the non-permissive temperature. This mutant defines a new gene, named BDF1. In a bdf1-1 strain, the reporter snRNA synthesized before the temperature shift remains stable at the non-permissive temperature. This demonstrates that the BDF1 gene affects the synthesis rather than the stability of the reporter snRNA and suggests that the BDF1 gene encodes a transcription factor. BDF1 is present in single copy on yeast chromosome XII, and is important for normal vegetative growth but not essential for cell viability. bdf1 null mutants share common phenotypes with several mutants affecting general transcription and are defective in snRNA production. BDF1 encodes a protein of 687 amino-acids containing two copies of the bromodomain, a motif also present in other transcription factors as well as a new conserved domain, the ET domain, also present in Drosophila and human proteins.

Analysis of the SIP3 protein identified in a two-hybrid screen for interaction with the SNF1 protein kinase

The Saccharomyces cerevisiae SIP3 gene was identified in a two-hybrid screen for proteins that interact in vivo with the SNF1 protein kinase, which is necessary for release of glucose repression. We showed that the C-terminal part of SIP3, recovered through its ability to interact with SNF1, strongly activates transcription when tethered to DNA. We have cloned and sequenced the entire SIP3 gene. The predicted 142-kD SIP3 protein contains a putative leucine zipper motif located in its C terminus. The native SIP3 protein also interacts with DNA-bound SNF1 and activates transcription of a target gene. A complete deletion of the SIP3 gene did not confer phenotypes characteristic of snf1 mutants. However, in a mutant deficient for the SNF1 kinase activity due to loss of the SNF4 stimulatory function, increased dosage of SIP3 partially restored expression of the glucose-repressible SUC2 gene. Overexpression of the C terminus of SIP3 caused defects in growth and SUC2 expression which were remedied by overexpressing SNF1. Taken together, these genetic data suggest that SIP3 is functionally related to the SNF1 protein kinase pathway.

Messenger RNA secondary structure and translational coupling in the Escherichia coli operon encoding translation initiation factor IF3 and the ribosomal proteins, L35 and L20

The Escherichia coli infC-rpmI-rplT operon encodes translation initiation factor IF3 and the ribosomal proteins, L35 and L20, respectively. The expression of the last cistron (rplT) has been shown to be negatively regulated at a post-transcriptional level by its own product, L20, which acts at an internal operator located within infC. The present work shows that L20 directly represses the expression of rpmI, and indirectly that of rplT, via translational coupling with rpmI. Deletions and an inversion of the coding region of rpmI, suggest an mRNA secondary structure forming between sequences within rpmI and the translation initiation site of rplT. To verify the existence of this structure, detailed analyses were performed using chemical and enzymatic probes. Also, mutants that uncoupled rplT expression from that of rpmI, were isolated. The mutations fall at positions that would base-pair in the secondary structure. Our model is that L20 binds to its operator within infC and represses the translation of rpmI. When the rpmI mRNA is not translated, it can base-pair with the ribosomal binding site of rplT, sequestering it, and abolishing rplT expression. If the rpmI mRNA is translated, i.e. covered by ribosomes, the inhibitory structure cannot form leaving the translation initiation site of rplT free for ribosomal binding and for full expression. Although translational coupling in ribosomal protein operons has been suspected to be due to the formation of secondary structures that sequester internal ribosomal binding sites, this is the first time that such a structure has been shown to exist.

Domains of the Escherichia coli threonyl-tRNA synthetase translational operator and their relation to threonine tRNA isoacceptors

The expression of the gene for threonyl-tRNA synthetase (thrS) is negatively autoregulated at the translational level in Escherichia coli. The synthetase binds to a region of the thrS leader mRNA upstream from the ribosomal binding site inhibiting subsequent translation. The leader mRNA consists of four structural domains. The present work shows that mutations in these four domains affect expression and/or regulation in different ways. Domain 1, the 3' end of the leader, contains the ribosomal binding site, which appears not to be essential for synthetase binding. Mutations in this domain probably affect regulation by changing the competition between the ribosome and the synthetase for binding to the leader. Domain 2, 3' from the ribosomal binding site, is a stem and loop with structural similarities to the tRNA(Thr) anticodon arm. In tRNAs the anticodon loop is seven nucleotides long, mutations that increase or decrease the length of the anticodon-like loop of domain 2 from seven nucleotides abolish control. The nucleotides in the second and third positions of the anticodon-like sequence are essential for recognition and the nucleotide in the wobble position is not, again like tRNA(Thr). The effect of mutations in domain 3 indicate that it acts as an articulation between domains 2 and 4. Domain 4 is a stable arm that has similarities to the acceptor arm of tRNA(Thr) and is shown to be necessary for regulation. Based on this mutational analysis and previous footprinting experiments, it appears that domains 2 and 4, those analogous to tRNA(Thr), are involved in binding the synthetase which inhibits translation probably by interfering with ribosome loading at the nearby translation initiation site.

Translated translational operator in Escherichia coli. Auto-regulation in the infC-rpmI-rplT operon

The genes coding for translation initiation factor IF3 (infC) and for the ribosomal proteins L35 (rpmI) and L20 (rplT) are transcribed in that order from a promoter in front of infC. The last two cistrons of the operon (rpmI and rplT) can be transcribed from a weak secondary promoter situated within the first cistron (infC). Previous experiments have shown that the expression of infC, the first cistron of the operon, is negatively autoregulated at the translational level and that the abnormal AUU initiation codon of infC is responsible for the control. We show that the expression of the last cistron (rplT) is also autoregulated at the posttranscriptional level. The L20 concentration regulates the level of rplT expression by acting in trans at a site located within the first cistron (infC) and thus different from that at which IF3 is known to act. This regulatory site, several hundred nucleotides upstream from the target gene (rplT), was identified through deletions, insertions and a point mutation. Thus, the expression of the operon is controlled in trans by the products of two different cistrons acting at two different sites. The localization within an open reading frame (infC) of a regulatory site acting in cis on the translation of a downstream gene (rplT) is new and was unforeseen since ribosomes translating through the regulatory site might be expected to impair either the binding of L20 or the mRNA secondary structure change caused by the binding. The possible competition between translation of the regions acting in cis and the regulation of the expression of the target gene is discussed.

The relation between catalytic activity and gene regulation in the case of E coli threonyl-tRNA synthetase

The expression of the gene for threonyl-tRNA synthetase (thrS) has previously been shown as being negatively autoregulated at the translational level. The region of the thrS leader mRNA responsible for that control is located immediately upstream of the ribosomal binding site, and was proposed to fold in a tRNA(Thr) anticodon arm-like structure. The present paper reviews experiments using enzymatic and chemical probes that prove the existence of a tRNA(Thr) anticodon-like structure in the thrS mRNA. These structural studies have also shown the presence of another arm upstream in the leader mRNA that has striking similarities with the acceptor arm of the tRNA(Thr) isoacceptors. This second arm was shown, by mutational analysis, to also be involved in thrS regulation. Footprinting experiments have shown that both the anticodon-like and the acceptor-like arms interact with the synthetase. Finally, the similarity of the interaction of the synthetase with its 2 RNA ligands (mRNA and tRNA) has been investigated by selecting and studying mutants of the synthetase itself. The observed correlation between regulatory and aminoacylation defects in these mutants strongly suggests that the synthetase recognizes similar regions of its 2 RNA ligands in an analogous manner.