Small heat-shock protein HspL is induced by VirB protein(s) and promotes VirB/D4-mediated DNA transfer in Agrobacterium tumefaciens

Agrobacterium tumefaciens is a Gram-negative plant-pathogenic bacterium that causes crown gall disease by transferring and integrating its transferred DNA (T-DNA) into the host genome. We characterized the chromosomally encoded alpha-crystallin-type small heat-shock protein (α-Hsp) HspL, which was induced by the virulence (vir) gene inducer acetosyringone (AS). The transcription of hspL but not three other α-Hsp genes (hspC, hspAT1, hspAT2) was upregulated by AS. Further expression analysis in various vir mutants suggested that AS-induced hspL transcription is not directly activated by the VirG response regulator but rather depends on the expression of VirG-activated virB genes encoding components of the type IV secretion system (T4SS). Among the 11 virB genes encoded by the virB operon, HspL protein levels were reduced in strains with deletions of virB6, virB8 or virB11. VirB protein accumulation but not virB transcription levels were reduced in an hspL deletion mutant early after AS induction, implying that HspL may affect the stability of individual VirB proteins or of the T4S complex directly or indirectly. Tumorigenesis efficiency and the VirB/D4-mediated conjugal transfer of an IncQ plasmid RSF1010 derivative between A. tumefaciens strains were reduced in the absence of HspL. In conclusion, increased HspL abundance is triggered in response to certain VirB protein(s) and plays a role in optimal VirB protein accumulation, VirB/D4-mediated DNA transfer and tumorigenesis

Placing preterm infants for sleep: first prone, then supine

Perspective on the paper by Kassim et al (see page 347

Detection of Acute Tubular Necrosis Using Blood Oxygenation Level-Dependent (BOLD) MRI

Background/Aims: To date, there is no imaging technique to assess tubular function in vivo. Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI) measures tissue oxygenation based on the transverse relaxation rate (R2*). The present study investigates whether BOLD MRI can assess tubular function using a tubule-specific pharmacological maneuver. Methods: Cross sectional study with 28 participants including 9 subjects with ATN-induced acute kidney injury (AKI), 9 healthy controls, and 10 subjects with nephron sparing tumor resection (NSS) with clamping of the renal artery serving as a model of ischemia/reperfusion (I/R)-induced subclinical ATN (median clamping time 15 min, no significant decrease of eGFR, p=0.14). BOLD MRI was performed before and 5, 7, and 10 min after intravenous administration of 40 mg furosemide. Results: Urinary neutrophil gelatinase-associated lipocalin was significantly higher in ATN-induced AKI and NSS subjects than in healthy controls (p=0.03 and p=0.01, respectively). Before administration of furosemide, absolute medullary R2*, cortical R2*, and medullary/cortical R2* ratio did not significantly differ between ATN-induced AKI vs. healthy controls and between NSS-I/R vs. contralateral healthy kidneys (p>0.05 each). Furosemide led to a significant decrease in the medullary and cortical R2* of healthy subjects and NSS contralateral kidneys (p<0.05 each), whereas there was no significant change of R2* in ATN-induced AKI and the NSS-I/R kidneys (p>0.05 each). Conclusion: BOLD-MRI is able to detect even mild tubular injury but necessitates a tubule-specific pharmacological maneuver, e.g. blocking the Na+-K+-2Cl- transporter by furosemide

Transient stent placement versus tubeless procedure after ureteroscopy retrograde surgery stone extraction (Fast Track Stent study 2)

$\bf Objectives$ To determine whether in pre-stented patients undergoing ureteroscopic stone removal (ureteroscopy retrograde surgery) a tubeless procedure provides a better outcome compared with short-term (6 h) ureteral stenting using an external ureteral catheter. $\bf Methods$ In this single academic center study (Fast Track Stent study 2), carried out between May 2016 and April 2018, 121 patients with renal or ureteral calculi were initially treated with double-J insertion. Before secondary ureteroscopy retrograde surgery, patients were prospectively randomized into two groups: tubeless versus ureteral catheter insertion for 6 h after ureteroscopy retrograde surgery. Exclusion criteria were acute urinary tract infection, solitary kidney or stone diameter >25 mm. Study end-points were stent-related symptoms assessed by a validated questionnaire (ureteral stent symptom questionnaire), administered both before and 4 weeks after surgery. Numerical ureteral stent symptom questionnaire scores were compared using the Mann–Whitney-U-test. The level of significance was defined as $\it P$ < 0.05. $\bf Results$ Ureteroscopy retrograde surgery procedures carried out by 13 surgeons resulted in >90% stone removal in all patients ($\it n$ = 121), with a mean operation time of 19.9 versus 18.0 min for ureteral catheter versus tubeless, respectively ($\it P$ = 0.37). Patient groups did not differ significantly in their ureteral stent symptom questionnaire scores (urinary index $\it P$ = 0.24; pain index $\it P$ = 0.35). Patients showed a significant preference for tubeless procedure over ureteral catheter reinsertion (Question GQ $\it P$ < 0.0001). The reintervention rate was 13.3% for the tubeless procedure ($\it n$ = 8) and 1.6% for the ureteral catheter group ($\it n$ = 1), respectively ($\it P$ = 0.034). $\bf Conclusions$ Short-term ureteral catheter and no stent insertion after ureteroscopy retrograde surgery stone extraction in pre-stented patients result in comparable quality of life. However, the reintervention rate is higher for tubeless procedures

Detection of acute tubular necrosis using blood oxygenation level-dependent (BOLD) MRI

$\it Background/Aims:$ To date, there is no imaging technique to assess tubular function in vivo. Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI) measures tissue oxygenation based on the transverse relaxation rate (R2*). The present study investigates whether BOLD MRI can assess tubular function using a tubule-specific pharmacological maneuver. $\it Methods:$ Cross sectional study with 28 participants including 9 subjects with ATNinduced acute kidney injury (AKI), 9 healthy controls, and 10 subjects with nephron sparing tumor resection (NSS) with clamping of the renal artery serving as a model of ischemia/reperfusion (I/R)-induced subclinical ATN (median clamping time 15 min, no significant decrease of eGFR, p=0.14). BOLD MRI was performed before and 5, 7, and 10 min after intravenous administration of 40 mg furosemide. $\it Results:$ Urinary neutrophil gelatinaseassociated lipocalin was significantly higher in ATN-induced AKI and NSS subjects than in healthy controls (p=0.03 and p=0.01, respectively). Before administration of furosemide, absolute medullary R2*, cortical R2*, and medullary/cortical R2* ratio did not significantly differ between ATN-induced AKI vs. healthy controls and between NSS-I/R vs. contralateral healthy kidneys (p>0.05 each). Furosemide led to a significant decrease in the medullary and cortical R2* of healthy subjects and NSS contralateral kidneys (p0.05 each). $\it Conclusion:$ BOLD-MRI is able to detect even mild tubular injury but necessitates a tubulespecific pharmacological maneuver, e.g. blocking the Na$^{+}$-K$^{+}$-2Cl- transporter by furosemide