An antibiotic produced by an insect-pathogenic bacterium suppresses host defenses through phenoloxidase inhibition

Photorhabdus is a virulent pathogen that kills its insect host by overcoming immune responses. The bacterium also secretes a range of antibiotics to suppress the growth of other invading microorganisms. Here we show that Photorhabdus produces a small-molecule antibiotic (E)-1,3-dihydroxy-2-(isopropyl)-5-(2-phenylethenyl)benzene (ST) that also acts as an inhibitor of phenoloxidase (PO) in the insect host Manduca sexta. The Photorhabdus gene stlA encodes an enzyme that produces cinnamic acid, a key precursor for production of ST, and a mutation in stlA results in loss of ST production and PO inhibitory activity, which are both restored by genetic complementation of the mutant and also by supplying cinnamic acid. ST is produced both in vitro and in vivo in sufficient quantities to account for PO inhibition and is the only detectable solvent-extractable inhibitor. A Photorhabdus stlA- mutant is significantly less virulent, proliferates slower within the host, and provokes the formation of significantly more melanotic nodules than wild-type bacteria. Virulence of the stlA- mutant is also rescued by supplying cinnamic acid. The proximate cause of the virulence effect, however, is the inhibition of PO, because the effect of the stlA- mutation on virulence is abolished in insects in which PO has been knocked down by RNA interference (RNAi). Thus, ST has a dual function both as a PO inhibitor to counter host immune reactions and also as an antibiotic to exclude microbial competitors from the insect cadaver.     

Allene formation by gold catalyzed cross-coupling of masked carbenes and vinylidenes

Addition of a sterically demanding cyclic (alkyl)(amino)carbene (CAAC) to AuCl(SMe(2)) followed by treatment with [Et(3)Si(Tol)](+)[B(C(6)F(5))(4)](-) in toluene affords the isolable [(CAAC)Au(eta(2)-toluene)](+)[B(C(6)F(5))(4)](-) complex. This cationic Au(I) complex efficiently mediates the catalytic coupling of enamines and terminal alkynes to yield allenes and not propargyl amines as observed with other catalysts. Mono-, di-, and tri-substituted enamines can be used, as well as aryl-, alkyl-, and trimethylsilyl-substituted terminal alkynes. The reaction tolerates sterically hindered substrates and is diastereoselective. This general catalytic protocol directly couples two unsaturated carbon centers to form the three-carbon allenic core. The reaction most probably proceeds through an unprecedented "carbene/vinylidene cross-coupling."     

Labor management in a patient with von Willebrand disease

von Willebrand disease (VWD) is an inherited bleeding disorder involving a deficiency or abnormal function of a blood clotting protein called von Willebrand factor (VWF). Deficiency of VWF, therefore, shows primarily in organs with small blood vessels such as the skin, the gastrointestinal tract and the uterus. This case report describes management of a patient presenting with type II von Willebrand disease in labor. She had history of life-threatening hemorrhage from an operation for deviated nasal septum and had a risk of severe postpartum hemorrhage (PPH) within 48 hors of delivery, which was avoided by appropriate planning and timely management.     

Comparison of arteriovenous fistula recirculation by thermodilution and urea - based method

Objective: To compare arteriovenous fistula recirculation by thermodilution technique and urea based two needle slow flow method. Design: Comparative cross-sectional study. Place and Duration of Study: Hemodialysis Unit of Nephrology Department of Shaikh Zayed Hospital, Lahore, from October 2005 to December 2005. Patients and Methods: Thirty one patients with end stage renal disease on maintenance hemodialysis through arteriovenous fistula were selected on purposive design. Hemodialysis was done on Fresenius 4008 S machines with in-built blood temperature monitoring module to measure recirculation by thermodilution method. Recirculation by the thermodilution method was calculated with the blood flow rate of 300 milliliter /minute and dialysate flow of 500ml /minute. Access recirculation by urea based method was calculated by taking three blood samples for blood urea nitrogen. Two samples were taken simultaneously from the arterial and venous ports respectively. Third sample was taken from the arterial port after slowing the blood flow pump to 50 milliliter/minute and waiting for 30 seconds. Relationship of thermodilution and urea based method was assessed by calculating Pearson correlation coefficient (r). Results: Out of 31 patients, 18 (58.1%) were males, whereas 13 (41.9%) were females. Their mean age was 47.29 +/- 13.42 years. Mean access recirculation by thermodilution method was 7.31 +/- 3.03 and by urea based method was 9.55 +/- 6.64. Correlation coefficient (r) was 0.706 with p-value of < 0.001, which was highly significant. Conclusion: Arteriovenous fistula recirculation calculated by thermo-dilution technique has a strong correlation with the recirculation calculated by the two-needle urea based method.     

Diffuse bilateral thalamic astrocytoma

Diffuse astrocytoma with bilateral thalamic involvement is extremely rare. We present a case of 10 years old female who presented with decreased mentation, dysarthria, decreased performance at school and later on with seizures. MRI scans were performed twice and were reported as Leigh's disease and hemimegalencephaly respectively. Patient presented again with complaint of unconsciousness, vomiting and chest congestion. No further imaging was performed. Biopsy showed grade III Astrocytoma with bilateral thalamic involvement. Patient was admitted to intensive care unit but could not survive and expired.     

Controlled Evaluation of Bactec Peds Plus/F and Bactec Lytic/10 Anaerobic/F Media for Isolation of Salmonella enterica Serovars Typhi and Paratyphi A from Blood

We compared anaerobic lytic (AL) and pediatric aerobic resin-containing (Peds Plus/F) blood culture media for the isolation of Salmonella enterica serotype Typhi or Paratyphi A from children. The yields from AL and Peds Plus/F media were the same with equal volumes of blood, but recovery was faster from AL medium than Peds Plus/F medium (10.7 and 16.4 h, respectively) (P < 0.001).     

Pathogenic variants in PIDD1 lead to an autosomal recessive neurodevelopmental disorder with pachygyria and psychiatric features

The PIDDosome is a multiprotein complex, composed by the p53-induced death domain protein 1 (PIDD1), the bipartite linker protein CRADD (also known as RAIDD) and the proform of caspase-2 that induces apoptosis in response to DNA damage. In the recent years, biallelic pathogenic variants in CRADD have been associated with a neurodevelopmental disorder (MRT34; MIM 614499) characterized by pachygyria with a predominant anterior gradient, megalencephaly, epilepsy and intellectual disability. More recently, biallelic pathogenic variants in PIDD1 have been described in a few families with apparently nonsydnromic intellectual disability. Here, we aim to delineate the genetic and radio-clinical features of PIDD1-related disorder. Exome sequencing was carried out in six consanguineous families. Thorough clinical and neuroradiological evaluation was performed for all the affected individuals as well as reviewing all the data from previously reported cases. We identified five distinct novel homozygous variants (c.2584C>T p.(Arg862Trp), c.1340G>A p.(Trp447*), c.2116_2120del p.(Val706Hisfs*30), c.1564_1565delCA p.(Gln522fs*44), and c.1804_1805del p.(Gly602fs*26) in eleven subjects displaying intellectual disability, behaviorial and psychiatric features, and a typical anterior-predominant pachygyria, remarkably resembling the CRADD-related neuroimaging pattern. In summary, we outlin`e the phenotypic and molecular spectrum of PIDD1 biallelic variants supporting the evidence that the PIDD1/CRADD/caspase-2 signaling is crucial for normal gyration of the developing human neocortex as well as cognition and behavior.Subject terms: Clinical genetics, Medical research     

Development and characteristics of a human cell assay for screening agents for melanoma prevention

This paper describes the development and initial evaluation of a human cell assay to identify potentially efficacious agents for preventing melanoma. Four human cell lines were used: normal melanocytes, a radial growth-phase-like melanoma cell line (WM3211), a vertical growth-phase-like melanoma cell line (Lu1205), and 83-2c, a cell strain cloned from metastatic melanoma. Four endpoints were evaluated in ultraviolet B-treated cells: annexin V, human leukocyte antigen-DR; E-cadherin, and N-cadherin. Annexin V was induced by nimesulide, 4-hydroxyphenylretinamide, and difluoromethylornithine in ultraviolet-B-treated radial growth-phase-like melanoma cells. None of the agents inhibited human leukocyte antigen-DR expression in ultraviolet-B-treated radial growth-phase-like melanoma cells, the only cells that strongly expressed human leukocyte antigen-DR. E-cadherin was overexpressed only in radial growth-phase-like melanoma cells relative to melanocytes, and ultraviolet B exposure dramatically reduced this expression. E-cadherin was only induced by difluoromethylornithine in ultraviolet-B-treated radial growth-phase-like melanoma cells. N-cadherin was over- expressed in all melanoma cell lines relative to melanocytes. In this study, all candidate preventive agents inhibited N-cadherin in ultraviolet B-treated radial growth-phase-like melanoma cells. Four agents inhibited N-cadherin in ultraviolet B-treated vertical growth-phase-like melanoma cells. The mean ratios of N-cadherin to E-cadherin levels and specific endpoint responses for both the radial growth-phase-like melanoma and vertical growth-phase-like melanoma cells were used to rank the agents. Agents were evaluated at clinically relevant concentrations. The rankings were difluoromethylornithine>4-hydroxyphenylretinamide>nimesulide>9-cis-retinoic acid>polyphenon E. Diphenylhydramine, D-mannitol, and nordihydroguaiaretic acid were inactive. The results of these initial studies suggest that ultraviolet-B-treated radial growth-phase-like melanoma cells are the most responsive to chemopreventive agents, and may be the cell line of choice for screening melanoma prevention agents.     

The Prognostic Value of Anemia in Patients with Diastolic Heart Failure

Anemia is prevalent in heart-failure patients, and it has been associated with increased mortality rates. In a retrospective study, we evaluated the effects of anemia on long-term survival in patients who experienced purely diastolic heart failure.Heart-failure patients with preserved systolic function (left ventricular ejection fraction, ≥0.50) were evaluated retrospectively. Of 294 patients, 162 had anemia (group 1) and 132 had no anemia (group 2) upon baseline examination. Anemia was defined as a hemoglobin level below 12 g/dL in women and below 13 g/dL in men. Multivariate Cox proportional hazards regression was conducted in order to test whether hemoglobin levels were an independent predictor of 5-year hospitalization and mortality rates in patients with diastolic heart failure. A P value less than 0.05 was considered statistically significant.Group 1 patients had a shorter mean survival time (37.8 ± 1.8 vs 44.9 ± 1.8 mo, P = 0.01); however, there was no significant difference between the groups in hospitalization rate (7.2 ± 7.1 vs 7.5 ± 6.3, P = 0.677). In a subgroup analysis, anemia was a significant predictor of higher mortality rates in elderly patients (age, >75 yr) who had diastolic heart failure (P = 0.018).We found that anemia is associated with increased long-term mortality rates in patients who have diastolic heart failure. In addition, anemia appears to be an independent predictor of worse outcomes in elderly heart-failure patients.Key words: Age factors, anemia/blood/complications/epidemiology/mortality, diastole, heart failure/blood/complications/mortality/physiopathology, hemoglobins/analysis, patient readmission, prevalence, risk assessment, survival analysis, ventricular function/leftAnemia is defined by the World Health Organization as a hemoglobin (Hb) level below 12 g/dL in women and below 13 g/dL in men.¹ A low Hb level is a significant risk factor in heart-failure patients: its association with increased death in this patient population has been shown, and it is an independent predictor of death.^2–4 Anemia has also been associated with increased rates of hospital readmission for heart failure.The optimal Hb level in patients with heart failure is still unclear, although a longitudinal study⁵ of a large population of patients with chronic heart failure showed that very high levels (≥17 g/dL) or low levels (<13 g/dL) independently predicted death and hospitalization for heart failure.In most studies in which the effect of anemia in heart failure has been examined, the focus has been on patients who experienced systolic heart failure. In the present study, we sought to evaluate the relationship of Hb levels with short- and long-term survival in patients who experienced diastolic heart failure with preserved systolic function.