Efficacy and safety of high versus standard dose ibuprofen for patent ductus arteriosus treatment in preterm infants: A systematic review and meta-analysis

BACKGROUND

Several small randomized controlled trials (RCTs) and observational studies have compared high (15-20/7.5-10/7.5-10 mg/kg/dose) versus standard dose (10/5/5 mg/kg/dose) ibuprofen for patent ductus arteriosus (PDA) closure, with limited evidence on efficacy and safety.

OBJECTIVE

To systematically review and meta-analyze studies of high versus standard dose ibuprofen for the closure of PDA in preterm infants.

METHODS

Databases were searched for RCTs and observational studies assessing high compared to standard dose of ibuprofen for PDA closure for preterm infants until August 2021. The primary outcome was failure of PDA closure after the first course of ibuprofen. The secondary outcomes were the failure of PDA closure after a second course of ibuprofen, rates of PDA ligation, all-cause mortality prior to hospital discharge, bronchopulmonary dysplasia, necrotizing enterocolitis, bleeding disorders, oliguria, and serum creatinine after treatment.

RESULTS

There were 6 studies with 369 patients (3 RCT, N = 190; 3 observational studies, N = 179). Compared to standard dose, high dose ibuprofen did not significantly decrease the failure rate of PDA closure in preterm infants after the first course (Relative risk (RR) 0.74, 95% confidence interval (CI) 0.53 -1.03, 6 studies, N = 369). High dose ibuprofen significantly decreased the rates of PDA ligation compared to standard dose (RR 0.33, 95% CI 0.16 -0.70, 5 studies, N = 309).

INTERPRETATION

Based on low-grade evidence, high dose ibuprofen may more effectively reduce rates of PDA ligation compared to standard dose with no increase in adverse effects, neonatal morbidities and mortality.

Incidence and predictors of eosinophilic myocardial hypersensitivity in patients receiving home dobutamine

Background

Home inotropes are utilised in those with end-stage heart failure as a bridge to cardiac transplantation. The use of intravenous dobutamine has been linked to cases of eosinophilic myocardial hypersensitivity (EMH), however, little is known about incidence and predictors.

Purpose

We sought to examine the incidence and possible predictors of eosinophilic myocardial hypersensitivity in a cohort of patients on home inotrope therapy at a cardiac transplant centre.

Methods

Patients enrolled in the home inotrope program with progression to heart transplantation or ventricular assist device (VAD) with available myocardial tissue for histopathology, from January 2000 to May 2020 were included. EMH was defined by a pathologist reporting eosinophilic infiltrate with hypersensitivity on myocardial histopathology.

Results

From a cohort of 74 patients, 58% (43) were on dobutamine and 42% (31) were on milrinone. There were zero cases of EMH in those on milrinone. EMH was identified in 14% (6/43) of patients receiving dobutamine. In the dobutamine cohort, the mean age was 52-±12 years, with 22% being female. Non-ischaemic dilated cardiomyopathy encompassed 62%, the remaining 38% were ischaemic cardiomyopathy. Median dobutamine dose (250 [200–282] mcg/min vs. 225 [200–291] mcg/min) and duration of therapy (41 [23–79] days vs. 53 [24–91] days) were similar between those with and without EMH. Rates of known allergy (27% vs. 33%) and asthma (1 patient in each group) were also similar between those with and without EMH. Those with EMH had a median peak eosinophil count of 0.40×109/L (IQR 0.21–0.66×109/L) compared to a peak of only 0.10×109/L (IQR 0.06–0.29×109/L) in the non-EMH cohort. There was a significant difference in the change in absolute eosinophil count between groups; over the duration of dobutamine therapy the median change in eosinophil count was 0.31×109/L (IQR 0.21–0.59×109/L) in the EMH group compared to 0.03×109/L (IQR 0.00–0.14×109/L) in the non-EMH cohort (p=0.02). Peak C-reactive protein was similar between groups (42±46mg/L vs. 44±45mg/L). Mean left ventricular ejection fraction (LVEF) reduced from 19% (±7%) to 17% (±2%) in those with EMH, while LVEF increased from 20% (±7%) to 22% (±9%) in non-EMH patients (Figure 1), p=NS. Re-presentation with heart failure requiring hospitalisation occurred in 83% in the EMH group compared to only 59% in the non-EMH group (p=0.26). The majority of patients with EMH (83%) required VAD as bridge to transplant, compared to only 41% of non-EMH (p=0.05).

Conclusion(s)

EMH occurred in 14% of patients receiving home dobutamine. Patients who developed EMH were more likely to require escalation in treatment to VAD as a bridge to heart transplant. In patients receiving dobutamine a reduction in LVEF, hospitalisation with decompensated heart failure and rising eosinophil count should prompt physicians to consider EMH.

Funding Acknowledgement

Type of funding sources: None. Figure 1

Systemic Mesenchymal Stem Cell-Derived Exosomes Reduce Myocardial Infarct Size: Characterization With MRI in a Porcine Model

The observations that mesenchymal stem cells (MSCs) exert cardiac protection and repair via their secretome with the active component(s) identified as exosomes underpinned our test of the efficacy of MSC exosomes in a porcine model of myocardial infarction (MI) when administered systemically by the convenient method of intravenous (IV) bolus injection. Results show that 7 days of IV exosomes results in clear reduction (30-40%) of infarct size measured at both 7 and 28 days post-MI, despite near identical release of hs Troponin T. Together with reduced infarct size, exosome treatment reduced transmurality and lessened wall thinning in the infarct zone. Exosome treated pigs showed relative preservation of LV function with significant amelioration of falls in fractional wall thickening compared with control. However, global measures of LV function were less protected by exosome treatment. It is possible that greater preservation of global LV function may have been attenuated by increased cardiac fibrosis, as T1 values showed significant increase in the exosome pigs compared to control particularly in the infarct related segments. Taken together, these results show clear effects of IV exosomes administered over 7 days to reduce infarct size with relatively preserved cardiac function compared to control treated infarct pigs.

Transcatheter versus surgical aortic valve replacement: an updated systematic review and meta-analysis with a focus on outcomes by sex

Background and purpose

Women at increased surgical risk have been shown to have better outcomes with transcatheter aortic valve implantation (TAVI) as compared to surgical valve replacement (SAVR). With the scope of TAVI moving into low-surgical risk patients we aimed to update the current literature to include the new low-risk randomized controlled trial data in investigating outcomes by sex.

Methods

We systematically searched MedlineOVID, PubMed, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov and reference lists for relevant randomised controlled trials (RCTs) comparing TAVI to SAVR published prior to October 7th 2019. Data extraction was performed by two independent authors and included trial design details, baseline characteristics and outcome data stratified by sex. Risk of bias was assessed using the Cochrane Risk of Bias 2 tool. Quantitative synthesis of pooled data was performed using Mantel-Haenszel fixed or random effects model. Q-statistic and the I2 test were used for assessment of heterogeneity.

Results

Our search yielded eight RCTs included in the final quantitative synthesis. The overall pooled cohort was 8,040, of whom 41.4% were female. Women had significantly lower rates of one-year all-cause mortality and one-year composite endpoint with TAVI as compared to SAVR. The selective mortality benefit with TAVI over SAVR in women did not persist to five-years. At 30-days, women demonstrated lower rates of major bleeding and acute kidney injury following TAVI compared to SAVR. For men, these outcomes were similar regardless of type of intervention. Both sexes were at increased risk of major vascular complications with TAVI as compared to SAVR, however women demonstrated nearly double the odds of major vascular complication with TAVI compared to men.

Conclusion

Our updated meta-analysis demonstrates that at one-year women undergoing TAVI have significantly lower mortality and better safety outcomes compared to those undergoing SAVR. These benefits are not seen in men. In the new low-risk era, these results are ever more important for guiding appropriate patient selection.

Composite endpoint at one-year

Funding Acknowledgement

Type of funding source: None

Systemic mesenchymal stem cell-derived exosomes reduce myocardial infarct size: characterization with MRI in a porcine model

Background

Mesenchymal stem cells (MSCs) have been shown to exert cardiac protection and repair via their secretome with the active component(s) identified as exosomes.

Purpose

To determine whether MSC-derived exosomes administered systemically by the convenient method of intravenous (IV) bolus injection reduce infarct size and improve cardiac function in an established porcine model of myocardial infarction (MI).

Methods

A total of 20 pigs underwent experimental MI by permanent ligation of the left circumflex coronary artery (LCX). Ten pigs (exosome treated) received twice daily IV injection of exosomes (1000ug protein equivalent) for 7 days. The remaining 10 pigs received vehicle control injections. Cardiac structure and function were measured by MRI which was performed at baseline (pre-MI) and repeated on days 7 and 28 post-MI. Infarct size was also confirmed post-mortem. Blood samples were drawn over first 7 days for measurement of hs Troponin T. The study followed the principles of laboratory animal care and was approved by our institution's IACUC.

Results

All LCX ligations resulted in permanent ischaemia with MI as evidenced by pallor of the myocardium, ECG changes including ST segment elevation and increases in plasma hs Troponin T. Exosomes administered IV for 7 days resulted in clear reduction (30–40%) of infarct size measured at both 7 (p<0.05) and 28 days (p<0.01) post-MI, despite near identical release of hs Troponin T. Together with reduced infarct size, exosome treatment reduced transmurality and lessened wall thinning (p<0.01) in the infarct zone. Exosome treated pigs showed relative preservation of LV function with significant amelioration of falls in fractional wall thickening (p<0.01) compared with control. However, global measures of LV function were less protected by exosome treatment. It is possible that greater preservation of global LV function may have been attenuated by increased cardiac fibrosis, as T1 values showed significant increase in the exosome pigs compared to control particularly in the infarct related segments.

Conclusion

Taken together, our results show clear effects of IV exosomes administered over 7 days to reduce infarct size with relatively preserved cardiac function compared to control treated infarct pigs.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): STaR Award (AM Richards), National Medical Research Council, Singapore. IAF-ICP, National Research Foundation, Singapore (RC Lai and SK Lim).

A porcine model of heart failure with preserved ejection fraction: magnetic resonance imaging and metabolic energetics

AIMS

A significant proportion of heart failure (HF) patients have HF preserved ejection fraction (HFpEF). The lack of effective treatments for HFpEF remains a critical unmet need. A key obstacle to therapeutic innovation in HFpEF is the paucity of pre-clinical models. Although several large animal models have been reported, few demonstrate progression to decompensated HF. We have established a model of HFpEF by enhancing a porcine model of progressive left ventricular (LV) pressure overload and characterized HF in this model including advanced cardiometabolic imaging using cardiac magnetic resonance imaging and hyperpolarized carbon-13 magnetic resonance spectroscopy.

METHODS AND RESULTS

Pigs underwent progressive LV pressure overload by means of an inflatable aortic cuff. Pigs developed LV hypertrophy (50% increase in wall thickness, P < 0.001, and two-fold increase in mass compared to sham control, P < 0.001) with no evidence of LV dilatation but a significant increase in left atrial volume (P = 0.013). Cardiac magnetic resonance imaging demonstrated T1 modified Look-Locker inversion recovery values increased in 16/17 segments compared to sham pigs (P < 0.05-P < 0.001) indicating global ventricular fibrosis. Mean LV end-diastolic (P = 0.047) and pulmonary capillary wedge pressures (P = 0.008) were elevated compared with sham control. One-third of the pigs demonstrated clinical signs of frank decompensated HF, and mean plasma BNP concentrations were raised compared with sham control (P = 0.008). Cardiometabolic imaging with hyperpolarized carbon-13 magnetic resonance spectroscopy agreed with known metabolic changes in the failing heart with a switch from fatty acid towards glucose substrate utilization.

CONCLUSIONS

Progressive aortic constriction in growing pigs induces significant LV hypertrophy with cardiac fibrosis associated with left atrial dilation, raised filling pressures, and an ability to transition to overt HF with raised BNP without reduction in LVEF. This model replicates many aspects of clinical HFpEF with a predominant background of hypertension and can be used to advance understanding of underlying pathology and for necessary pre-clinical testing of novel candidate therapies.

Evaluating Caregiver Management of Asthma Exacerbations at Home

BACKGROUND: Effective management of asthma in the home setting requires asthma education from a health professional along with written plans for asthma exacerbations. These approaches can result in fewer acute asthma visits, fewer missed school days and better asthma control. Nevertheless, a large number of asthma exacerbations result in emergency department visits or hospital admission. Several studies suggest that care-givers may lack the knowledge, the skills, or the confidence to provide care for their child during an asthma exacerbation.

OBJECTIVES: The objective of this study was to determine the proportion of caregivers who appropriately manage their child’s acute asthma at home (as per the 2014 Global Initiative for Asthma guidelines) and to identify factors that may be associated with deviations from these guidelines.

DESIGN/METHODS: We studied caregivers of children who are known to suffer from asthma using a paper based questionnaire in a single-center outpatient asthma clinic. Caregivers of children aged 3 to 17 years with a physician made diagnosis of asthma greater than 6 months in duration were included. To avoid a diagnosis of bronchiolitis from our study group, new consultations for wheezing or cough without a prior diagnosis of asthma, and less than 3 years of age were excluded. For statistical analysis, we used Excel and STATA 11 for the z test of proportions and comparison of means with a one way ANOVA (a = 0.05).

RESULTS: Among the 45 caregivers surveyed, most had children with well controlled asthma based on low scores from a standard asthma control test and a limited number of emergency room visits (1.5±0.1 per year). Sixty-four percent of caregivers were able to correctly identify the initial treatment with 2 puffs of Ventolin; however, 54% did not choose repeating Ventolin treatment within 20 minutes for ongoing symptoms. Moreover, only 58% of caregivers had ever been given a written asthma action plan. Caregivers had a higher degree of confidence (reported on a scale of 1-10) in initiating management (8.9±1.5) compared with stopping treatment (7.3±2.5).

CONCLUSION: Despite a high degree of confidence in starting treatment for asthma attacks, half of the caregivers surveyed identified inappropriate steps to manage asthma exacerbations at home. Providing a written asthma action plan may improve caregiver confidence and knowledge in asthma exacerbation management. However, routine assessment and review by a healthcare professional is essential in reinforcing recommended behaviours for home asthma management.

Transanal rectal resection: an initial experience of 20 cases

AIM

Low anterior resection (LAR) can present a formidable surgical challenge, particularly for tumours located in the distal third of the rectum. Transanal total mesorectal excision (taTME) aims to overcome some of these difficulties. We report our initial experience with this technique.

METHOD

From June 2013 to September 2014, 20 selected patients underwent transanal rectal resection for various malignant and benign low rectal pathologies. All patients with rectal cancer were discussed at a multidisciplinary team meeting. Data were entered into a prospective managed international database.

RESULTS

Of the 20 patients (14 male), seventeen (85%) had rectal cancer lying at a median distance of 2 cm (range 0-7) from the anorectal junction. The operations performed included LAR (16). Abdominoperineal excision (2) and completion proctectomy (2), all of which were performed by a minimally invasive approach with three conversions. The mean operation time was 315.3 min. There were six postoperative complications of which two (10%) were Clavien-Dindo Grade IIIb (pelvic haematoma and a late contained anastomotic leakage). The median length of stay was 7 days. The TME specimen was intact in 94.1% of cancer cases. The mean number of harvested lymph nodes was 23.2. There was only one positive circumferential resection margin (tumour deposit; R1 rate 5.9%). One patient developed a distant recurrence (median follow-up 10 months, range 6-21).

CONCLUSION

TaTME was safe in this small series of patients. It is especially attractive in patients with a narrow and irradiated pelvis and a tumour in the lower third of the rectum. TaTME is technically demanding, but the good outcomes should prompt randomized studies and prospective registration of all taTME cases in an international registry.

Colorectal cancer stem cells: Characterization and functional analysis

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Background: Cancer stem cells are defined as cells within a tumour that are able to self-renew and differentiate into all cell lineages within that tumour. With our extensive panel of colorectal cell lines, our aims are: 1) To characterise and isolate cancer stem cells based on stem cell markers, morphological appearances and the ability to form multiple lineages; 2) To understand how cancer stem cells drive tumour growth and progression. Methods: 1) Fluorescent Activated Cell Sorting (FACS); 2) In vitro soft agar clonogenic and Matrigel differentiation assays; 3) In vivo tumourigenic NOD/SCID mice assay; 4) Confocal immunofluorescence imaging. Results: 1) A subpopulation of cells can differentiate into crypt-like megacolonies, retaining the ability to self-renew and differentiate. SW1222 cell line forms heterogeneous colonies when single cells are plated in Matrigel. Megacolonies can both self-renew and form terminally differentiated small colonies, whereas small colonies cannot form megacolonies. Megacolonies develop crypt-like structures and increase their expression of differentiation markers (CDX-1, CK-20) over time. Experiments are currently under way to confirm that cells from megacolonies are able to initiate tumours in NOD/SCID mice. Some cell lines retain the ability to differentiate into both neuroendocrine and epithelial lineages. 2) CD44+CD24+ enriches for the cancer stem cell population. Colorectal cancer cell lines HCT116, HT29, LS180, LS174T and SW1222 express both CD44 and CD24. The CD44+CD24+ subpopulation is the most clonogenic. In SW1222, CD44+CD24+ cells enrich for megacolonies and can reform all four CD44/CD24 subpopulations. 3) Hypoxia reduces differentiation, increases stem-like phenotype and enhances clonogenicity. Hypoxia increases the proportion of undifferentiated colorectal cancer cells when plated on Matrigel and increases clonogenicity. Conclusions: 1) Colorectal cancer cell lines contain subpopulations of cells that have the ability to self-renew, differentiate and drive tumour growth, and may be characterised by their cell surface markers and colony morphology. 2) CD44+CD24+ can be used as markers for colorectal cancer stem cells. 3) Hypoxia increases the stem-like phenotype of cancer cells, reduces differentiation and increases clonogenicity.

No significant financial relationships to disclose.

Technical note: a transparent template system for positioning independent radiation-therapy shielding blocks

To assist the radiation therapist/technologist with setting up patients for radiation therapy treatments, a set of accessories has been developed for placing a transparent template of the treatment-field border in the light-field of a radiation teletherapy unit. These accessories permit the efficient, accurate, and reproducible manual placement of independent lead-shielding blocks. Software has been developed to print templates on standard transparency sheets using a laser printer. A transparent template holder slides into the wedge slot of the teletherapy unit. The template holder features 2 alignment pegs to assure rapid, accurate, and reproducible placement of the template. A specially-developed hole-punch is used to cut, in the template, alignment holes that fit snugly over the pegs of the template holder. This system currently supports Siemens MX and KD units and the Theratronics Theratron 780C Co unit, as well as the Helax TMS block file format.

COPII-coated vesicle formation reconstituted with purified coat proteins and chemically defined liposomes

COPII vesicle formation requires only three coat assembly subunits: Sar1p, Sec13/31p, and Sec23/24p. PI 4-phosphate or PI 4,5-bisphosphate is required for the binding of these proteins to liposomes. The GTP-bound form of Sar1p recruits Sec23/24p to the liposomes as well as to the ER membranes, and this Sar1p-Sec23/24p complex is required for the binding of Sec13/31p. Ultrastructural analysis shows that the binding of COPII coat proteins to liposomes results in coated patches, coated buds, and coated vesicles of 50-90 nm in diameter. Budding proceeds without rupture of the donor liposome or vesicle product. These observations suggest that the assembly of the COPII coat on the ER occurs by a sequential binding of coat proteins to specific lipids and that this assembly promotes the budding of COPII-coated vesicles.

High-risk mild head injury

The generally accepted definition of mild head injury includes Glasgow Coma Scale (GCS) scores of 13 to 15. However, many studies have shown that there is a heterogeneous pathophysiology among patients with GCS scores in this range. The current definition of mild head injury is misleading because patients classified in this category can have severe sequelae. Therefore, a prospective study of 1360 head-injured patients with GCS scores ranging from 13 to 15 who were admitted to the neurosurgery service during 1994 and 1995 was undertaken to modify the current definition of mild head injury. Data regarding patients' age, sex, GCS score, radiographic findings, neurosurgical intervention, and 6-month outcome were collected and analyzed. The results of this study showed that patients with lower GCS scores tended to have suffered more serious injury. There was a statistically significant trend across GCS scores for percentage of patients with positive acute radiographic findings, percentage receiving neurosurgical interventions, and percentage with poor outcome. The presence of postinjury vomiting did not correlate with findings of acute radiographic abnormalities. Based on the results of this study, the authors divided all head-injured patients with GCS scores ranging from 13 to 15 into mild head injury and high-risk mild head injury groups. Mild head injury is defined as a GCS score of 15 without acute radiographic abnormalities, whereas high-risk mild head injury is defined as GCS scores of 13 or 14, or a GCS score of 15 with acute radiographic abnormalities. This more precise definition of mild head injury is simple to use and may help avoid the confusion caused by the current classification.

Uncoupled packaging of targeting and cargo molecules during transport vesicle budding from the endoplasmic reticulum

Formation of vesicular intermediates in protein transport between the endoplasmic reticulum and the Golgi apparatus involves a mechanism that sorts and packages two classes of molecules into transport vesicles: targeting molecules, which are required for targeting and consumption of vesicular intermediates, and cargo proteins. In order to examine the importance of cargo in this packaging reaction, we developed an in vitro assay that quantifies vesicle formation based on segregation of targeting molecules. Here we document that endoplasmic reticulum devoid of cargo proteins is competent in the formation and release of targeting molecule-containing vesicles in a fashion indistinguishable from its normal counterpart. This observation implies that packaging of cargo proteins may be uncoupled from the recruitment of targeting molecules during vesicle budding from the endoplasmic reticulum. Using the same assay, we demonstrate that the packaging of targeting molecules into vesicles is not dependent on the lumenal chaperone, BiP (Kar2p).

COPII: a membrane coat formed by Sec proteins that drive vesicle budding from the endoplasmic reticulum

In vitro synthesis of endoplasmic reticulum-derived transport vesicles has been reconstituted with washed membranes and three soluble proteins (Sar1p, Sec13p complex, and Sec23p complex). Vesicle formation requires GTP but can be driven by nonhydrolyzable analogs such as GMP-PNP. However, GMP-PNP vesicles fail to target and fuse with the Golgi complex whereas GTP vesicles are functional. All the cytosolic proteins required for vesicle formation are retained on GMP-PNP vesicles, while Sar1p dissociates from GTP vesicles. Thin section electron microscopy of purified preparations reveals a uniform population of 60-65 nm vesicles with a 10 nm thick electron dense coat. The subunits of this novel coat complex are molecularly distinct from the constituents of the nonclathrin coatomer involved in intra-Golgi transport. Because the overall cycle of budding driven by these two types of coats appears mechanistically similar, we propose that the coat structures be called COPI and COPII.

The Sec13p complex and reconstitution of vesicle budding from the ER with purified cytosolic proteins

SEC13 encodes a 33 kDa protein that participates in vesicle budding from the endoplasmic reticulum (ER). In order to purify a functional form of Sec13p, a SEC13-dihydrofolate reductase (mouse) fusion gene (SEC13:DHFR) was constructed that complements both sec13 temperature sensitive and null mutations. Methotrexate-agarose affinity chromatography facilitated the purification of two forms of the Sec13-dhfrp fusion protein: a monomeric form and a high molecular weight complex. The complex form consists of two subunits: Sec13-dhfrp and a 150 kDa protein (p150). Native immunoprecipitation experiments confirm that Sec13p exists in a complex with p150 in wild type cells. Functional analysis supports a role for both subunits in protein transport. Vesicle budding from the ER in a cell-free reaction is inhibited by Fab antibody fragments directed against either Sec13p or p150. The purified Sec13-dhfrp/p150 complex, but not the Sec13-dhfrp monomer, in combination with two other pure protein fractions (Sar1p and a Sec23/Sec24 protein complex) satisfies the requirement for cytosol in a cell-free vesicle budding reaction. The vesicles formed with the purified protein fractions are competent to fuse with the Golgi and are biochemically distinct from the ER membrane fraction from which they derive.

Sequence and expression of the Escherichia coli recR locus

The Escherichia coli RecR protein participates in a recombinational DNA repair process. Its gene is located in a region of chromosome that extends from 502 to 509 kilobases on the physical map and that contains apt, dnaX, orf12-recR, htpG, and adk. Most, if not all, of these are involved in nucleic acid metabolism. The orf12-recR reading frames consist of 935 base pairs and overlap by one nucleotide, with the 3' A of the orf12 termination codon forming the 5' nucleotide of the recR initiation codon. The orf12-recR promoter was located upstream of orf12 by sequence analysis, promoter cloning, and S1 nuclease protection analysis. The start point of transcription was determined by primer extension. The transcript 5' end contained a long, apparently untranslated region of 199 nucleotides. Absence of a detectable promoter specific for recR and the overlap of the orf12 and recR reading frames suggest that translation of recR is coupled to that of orf12. By maxicell analysis, it was determined that both orf12 and recR are translated.