Enhanced inhibition of Pseudomonas aeruginosa virulence factor production and biofilm development by sublethal concentrations of eugenol and phenyllactic acid.

Biofilm development in Pseudomonas aeruginosa is regulated by its quorum sensing (QS) systems. It has three major QS systems: LasI/R, RhlI/R and PQS/MvfR. Previous studies showed that phenyllactic acid (PLA) binds to RhlR and PqsR and inhibits the Rhl and PQS QS; and eugenol at sublethal concentration inhibits Las and PQS QS systems. Here, we have demonstrated that a combination of sublethal doses of eugenol and PLA enhanced the inhibition of the QS mediated production of the virulence factors and biofilm development of this pathogen. A combination of 50 µmol l-1 eugenol and 0·3 mmol l-1 PLA significantly inhibited the pyocyanin production, protease activity, swarming motility and cytotoxic activities of P. aeruginosa strain PAO1, whereas eugenol and PLA when added individually to PAO1 cultures were less effective in inhibiting its virulence factor expression. Biofilm formation of PAO1 was reduced by 32, 19 and 87% on glass surfaces; and 54, 49 and 93% on catheter surfaces when treated using 50 µmol l-1 eugenol or 0·3 mmol l-1 PLA and their combinations, respectively. The in vitro finding in the reduction of biofilm development was further validated in vivo using a catheter associated medaka fish biofilm model. Our results indicate that a combination of QS inhibitors targeting different QS pathways should be selected while designing therapeutic molecules to achieve maximum QS mediated biofilm inhibition and clinical outcome against P. aeruginosa.

Measurement of the Electrical Properties of a Thundercloud Through Muon Imaging by the GRAPES-3 Experiment.

The GRAPES-3 muon telescope located in Ooty, India records rapid (∼10 min) variations in the muon intensity during major thunderstorms. Out of a total of 184 thunderstorms recorded during the interval of April 2011-December 2014, the one on December 1, 2014 produced a massive potential of 1.3 GV. The electric field measured by four well-separated (up to 6 km) monitors on the ground was used to help estimate some of the properties of this thundercloud, including its altitude and area that were found to be 11.4 km above mean sea level and ≥380 km^{2}, respectively. A charging time of 6 min to reach 1.3 GV implied the delivery of a power of ≥2 GW by this thundercloud that was moving at a speed of ∼60 km h^{-1}. This work possibly provides the first direct evidence for the generation of gigavolt potentials in thunderclouds that could also possibly explain the production of highest-energy (100 MeV) gamma rays in the terrestrial gamma-ray flashes.

Transient Weakening of Earth's Magnetic Shield Probed by a Cosmic Ray Burst.

The GRAPES-3 tracking muon telescope in Ooty, India measures muon intensity at high cutoff rigidities (15-24 GV) along nine independent directions covering 2.3 sr. The arrival of a coronal mass ejection on 22 June 2015 18:40 UT had triggered a severe G4-class geomagnetic storm (storm). Starting 19:00 UT, the GRAPES-3 muon telescope recorded a 2 h high-energy (∼20 GeV) burst of galactic cosmic rays (GCRs) that was strongly correlated with a 40 nT surge in the interplanetary magnetic field (IMF). Simulations have shown that a large (17×) compression of the IMF to 680 nT, followed by reconnection with the geomagnetic field (GMF) leading to lower cutoff rigidities could generate this burst. Here, 680 nT represents a short-term change in GMF around Earth, averaged over 7 times its volume. The GCRs, due to lowering of cutoff rigidities, were deflected from Earth's day side by ∼210° in longitude, offering a natural explanation of its night-time detection by the GRAPES-3. The simultaneous occurrence of the burst in all nine directions suggests its origin close to Earth. It also indicates a transient weakening of Earth's magnetic shield, and may hold clues for a better understanding of future superstorms that could cripple modern technological infrastructure on Earth, and endanger the lives of the astronauts in space.

Effects of rituximab-based B-cell depletion therapy on skin manifestations of lupus erythematosus--report of 17 cases and review of the literature.

Cutaneous manifestations occur frequently in systemic lupus erythematosus (SLE) and are pathognomonic in subacute-cutaneous lupus erythematosus (SCLE) and chronic cutaneous lupus erythematosus (CCLE). Although B-cell depletion therapy (BCDT) has demonstrated efficacy in SLE with visceral involvement, its usefulness for patients with predominant skin manifestations has not been fully established. In this single-centre, retrospective study 14 consecutive SLE, one CCLE and two SCLE patients with recalcitrant skin involvement were treated with 2 × rituximab 1 g, and 1 × cyclophosphamide 750 mg. Six months after BCDT, nine of 17 (53%) patients were in complete (CR) or partial remission (PR). Relapses occurred in 12 patients (71%) at a mean time of 10 ± 1.8 months after BCDT. A second cycle of BCDT achieved a more sustained remission in seven of nine patients (78%) lasting for a mean time of 18.4 ± 2.7 months. Minor adverse events were experienced by three patients. Mean follow-up was 30 months. Our own results and the literature review demonstrate that BCDT based on rituximab is well tolerated and may be effective for cutaneous lesions of lupus erythematosus. Randomized controlled trials are necessary to further evaluate the value of BCDT for this group of patients.

Specific induction of the 70-kD heat stress proteins by the tyrosine kinase inhibitor herbimycin-A protects rat neonatal cardiomyocytes. A new pharmacological route to stress protein expression?

Heat shock protein (hsp) induction by stressful stimuli such as heat and ischemia is known to protect cardiac cells from severe stress. The ability to induce hsp's in the heart directly by "nonstressful" means would potentially have important clinical implications. In noncardiac cells, the tyrosine kinase inhibitor herbimycin-A has been shown to induce the 72-kD hsp. We therefore examined whether herbimycin-A and another tyrosine kinase inhibitor, genistein, could induce 70-kD hsp's in primary cultures of rat neonatal cardiomyocytes, and whether these treatments protect against severe stress. Primary cardiomyocytes were incubated with herbimycin-A or genistein. hsp induction was measured 16-20 h later by Western blotting. Cell survival after subsequent lethal heat stress or simulated ischemia was assessed using trypan blue exclusion and released lactate dehydrogenase activity. Our results indicate that, in cardiac cells, herbimycin-A induces 70-kD hsp's but not hsp90, -60, -25, or glucose-regulated protein 78, whereas genistein has no effect on hsp's. Moreover, hsp induction correlated with the ability of herbimycin-A to protect cells against severe stress, whereas genistein has no protective effects. This suggests that herbimycin-A may induce 70-kD hsp's via a tyrosine kinase-independent mechanism. These results indicate the possibility of a pharmacological approach to HSP70 induction and cardiac protection, which may ultimately be of clinical relevance.

Angiotensin-converting enzyme inhibitors potentiate preconditioning through bradykinin B2 receptor activation in human heart.

OBJECTIVES: This study was designed to determine whether angiotensin-converting enzyme (ACE) inhibitors play a role in cardioprotection in a human model of preconditioning. BACKGROUND: Recent studies have suggested that bradykinin may contribute to the protective effects of preconditioning in animal models. ACE inhibitors are known to inhibit the degradation of bradykinin and hence may be able to potentiate the effect of preconditioning. METHODS: We examined the effects of the ACE inhibitors captopril and lisinopril in combination with a subthreshold preconditioning stimulus (i.e., insufficient to have any protective effects alone). Human atrial trabeculae were superfused with Krebs buffer and paced at 1 Hz. They were subjected to a full or subthreshold preconditioning stimulus consisting of either 3 or 1.5 min of simulated ischemia and 7 min of reoxygenation. In each instance, this stimulus was followed by 90 min of simulated ischemia and 2 h of reoxygenation. In addition, the subthreshold preconditioned group had 20 min of previous ACE inhibitor treatment. RESULTS: Recovery of contractile function (percent of baseline) was 22 +/- 1% (mean +/- SEM) in the control group versus 61 +/- 1% in the preconditioned group. The subthreshold preconditioned group and the ACE inhibitor-alone groups did not exhibit any protection; however, in combination, the protection was significant (71 +/- 4% in the captopril group, 58 +/- 8% in the lisinopril group, p < 0.005) compared with the control group. There was no significant difference between these values and recovery after the full preconditioning stimulus. Furthermore, Hoe 140, a specific bradykinin B2 receptor antagonist, abolished the protection. CONCLUSIONS: To our knowledge, these are the first results in human muscle to suggest that ACE inhibitors may augment ischemic preconditioning, possibly through B2 receptor activation.

Occupational exposure to ionizing radiation has no effect on T- and B-cell total counts or percentages of helper, cytotoxic and activated T-cell subsets in the peripheral circulation of male radiation workers.

PURPOSE: To investigate changes in immune cell subsets in the peripheral circulation of a male population occupationally exposed to ionizing radiation. MATERIALS AND METHODS: Peripheral blood samples were taken from 194 male workers with cumulative exposures of >200 mSv (mean exposure 331.5 mSv, mean age 51 years) and from a reference population of 131 male workers with cumulative exposures of <27.5 mSv (mean exposure 13.9 mSv, mean age 47 years). Samples were analysed by flow cytometry for T- and B-cell total counts and for the T-cell subset percentages of CD4+ (helper T-cells), CD8+ (cytotoxic T-cells) and CD3+/HLA-DR+ (activated T-cells). RESULTS: Comparison of the >200 and <27.5 mSv exposure groups using linear regression analysis showed no statistically significant differences between the two groups for T-cell total count, B-cell total count or for percentages of the T-cell subsets CD4+, CD8+ or CD3+/HLA-DR+ and CD4+:CD8+. However, statistically significant increases in both T- and B-cell total counts were observed within the two exposure groups and data pooled from both groups when non-smokers (never and ex-smokers) were compared with current smokers. For pooled data T-cell total count increased in smokers by 35% (p=0.0001) and B-cell total count increased by 37% (p=0.0004). CONCLUSIONS: No significant immunological effects were observed in male radiation workers with cumulative exposures of >200 mSv when compared with a reference population with cumulative exposures of <27.5 mSv, although highly significant increases in both T- and B-cell total counts were observed in smokers compared with non-smokers.

Factors influencing pediatric injury in side impact collisions.

Side impacts collisions pose a great risk to children in crashes but information about the injury mechanisms is limited. The heights and weights of children vary widely and as a result, the injury patterns may vary across the pediatric age range. This study involves a case series of children in side impact collisions who were identified through Partners for Child Passenger Safety, a large child-focused crash surveillance system. The aim of the current study was to use in-depth crash investigations to identify injury mechanisms to children in side impact collisions. 93 children in 55 side impact crashes were studied. 23% (n = 22) of the children received an AIS > or = 2 (clinically significant) injury. In these 22 children, head (39%), extremity (22%), and abdominal injuries (17%) were the most common significant injuries. The cases revealed that serious injuries occur even in minor crashes. Cases that illustrate body region-specific injury mechanisms are discussed.

A serological survey of bovine brucellosis in the Molopo District of Bophuthatswana.

A serological investigation was carried out in the Molopo district of Bophuthatswana to determine the prevalence of brucellosis titre in heifers and cows (n = 9,675) over 24 months of age, which were grazing on communal tribal and privately owned land. The Rose Bengal, micro serum agglutination and complement fixation (CFT) tests were used. Two hundred and two (2.1%) animals tested positive with a CFT titre of 30 (IU ml-1) or higher. Factors that could have contributed to the relatively low prevalence are discussed.

Aortic thromboembolism associated with traumatic reticuloperitonitis in a downer cow.

A large thrombus was found at the ileal bifurcation on post mortem examination of a 6-year-old Jersey cow which presented clinically with a history of acute onset recumbency, hind limb paresis and skin necrosis over the sacral area. Other significant findings on post mortem were traumatic reticuloperitonitis accompanied by mural thrombosis of the left ventricle associated with a purulent sinus tract through the ventricular wall, fibrous adhesions between the pericardium, diaphragm and liver, and multiple infarcts in both kidneys.

Serological survey to determine the prevalence of bovine leukaemia virus antibodies in dairy cattle on selected farms in the Gauteng and Mpumalanga provinces.

Cattle from a farm where enzootic bovine leukosis had been diagnosed were tested to determine the prevalence of bovine leukaemia virus antibodies. Farmers who had bought cattle from this farm were identified and their herds also tested. Of 381 adult dairy cattle tested, 14 animals reacted positively (3.67%). Cattle (n = 81) from 3 selected herds, not associated with the affected farm were also bled and 7 animals reacted positively (8.64%).

The possible role of two common three-host ticks, Rhipicephalus appendiculatus and Amblyomma hebraeum, in the transmission of bovine leukosis virus.

The possible role of Rhipicephalus appendiculatus and Amblyomma hebraeum in the mechanical and transstadial transmission of bovine leukosis virus (BLV) was investigated. BLV-free laboratory strains of R. appendiculatus and A. hebraeum nymphal ticks (n = 400) were fed on a BLV-infected and a negative control bovine. At various intervals after engorgement the ticks were homogenised and injected subcutaneously into BLV-negative sheep. Adult R. appendiculatus and A. hebraeum, which had fed as nymphs on the BLV-infected bovine, were then allowed to feed on BLV-negative sheep. A control sheep was also injected intravenously with blood from the infected bovine. Only the control sheep that received blood from the BLV-positive bovine seroconverted 9 months later. All the other surviving sheep remained serologically negative during the 13 months observation period. It is suggested that the nymphal stages of these ticks probably do not play a role in the transstadial transmission of BLV in southern Africa. The significance of these results is discussed.

Heat shock proteins and the skin.

Heat shock proteins are of fundamental importance in cutaneous biology, from protection against UV-induced damage to wound healing and repair. Heat shock proteins have important regulatory roles in the control of apoptosis, regulation of steroid aporeceptors, kinases, and other protein remodelling events. They are also implicated in the control of cell growth, and as such, are potential targets for cancer diagnosis and treatment. Currently, emphasis is being placed on the potential use of these proteins in the prevention and treatment of disease. Therapeutic manipulation of these proteins may ultimately lead to novel treatments for diseases as diverse as melanoma to epidermolysis bullosa.

A comparison of different rigid contact lenses: edge thicknesses and contours.

The edge thickness and contour of rigid lenses is an important factor in lens comfort and acceptance. In this study the edges of two CAB lenses, a PMMA-silicone combination lens, a pure silicone lens had standard PMMA lenses are evaluated by molding the lenses. Considerable variation in thickness and contour of the peripheral portion of the lenses were found.

Persistent anticonvulsant hypersensitivity syndrome responding to ciclosporin.

The drug hypersensitivity syndrome is a severe, multisystem reaction that typically develops within 2 months of starting a drug. We describe a case which has been unusually persistent, requiring prolonged treatment with systemic corticosteroids and after 1 year, ciclosporin. To the best of our knowledge, the use of ciclosporin for the treatment of the drug hypersensitivity syndrome has not been described previously.

An unusual presentation of diffuse granuloma annulare in an HIV-positive patient - immunohistochemical evidence of predominant CD8 lymphocytes.

Over the past decade there have been several reports in the literature of atypical forms of granuloma annulare (GA) occurring in HIV positive patients. We now report a case of diffuse granuloma annulare in an HIV positive patient with unusual clinical and immunohistological features. Our patient presented with a persistent extensive macular erythematous eruption on his face and upper trunk with bizarre sparing around the nipples and axillae. The histology showed an interstitial pattern of GA, with a predominance of CD8 positive cells, in contrast to the usual CD4 positive infiltrate typically seen in GA.

Misuse of booster seats.

OBJECTIVE: To describe several aspects of booster seat use and misuse in a sample of children attending child safety seat clinics. METHODS: Booster seat practices were assessed at 76 child safety seat clinics held between April 1997 and January 1999 in Pennsylvania and southern New Jersey. At each assessment, a child passenger safety team evaluated the booster seat and identified modes of misuse. RESULTS: Altogether 227 booster seats were observed. Sixty eight per cent (68%) of shield boosters and 20% of belt positioning boosters were misused. Thirty two per cent of the children using a shield booster weighed more than 40 lb (18.1 kg); 68% of children in shield boosters and 63% in belt positioning boosters weighed less than 40 lb. CONCLUSION: This study identified a relatively high rate of booster seat misuse. Shield boosters were more likely to be misused than belt positioning booster seats. Significant numbers of children weighing more than 40 lb were using possibly dangerous shield boosters. The majority of children in this study were less than 40 lb. In this weight range, a convertible child restraint system provides better protection than a booster seat. Booster seat use should only be initiated once the child has completely outgrown their convertible child restraint system.

Assessing child restraint misuse by parental survey.

OBJECTIVE: To determine the extent to which child restraint system (CRS) misuse can be evaluated by parental survey. METHODS: A cross sectional survey was conducted at eight CRS clinics from May to October, 1998. Before CRS inspection, parents were administered a structured interview to identify distinct characteristics of restraint use and misuse. After the interview, a certified child passenger safety technician team independently evaluated the restraint system and identified specific modes of misuse. Parent descriptions of CRS use were compared with observations of the technician and the degree of agreement between the two was assessed for several specific attributes of use. RESULTS: A total of 100 children restrained in convertible CRSs were included in the study. Parents were able to accurately report several aspects of child restraint use-in particular, the attachment and fit of the CRS, the use of the harness clip, and the CRS incline. Parents were less accurate in their characterization of the fit of the child in the CRS. For nearly every item assessed, parents were more accurate in their description of correct compared with incorrect use. CONCLUSIONS: Interview tools can be developed that enable parents to describe aspects of CRS use and that screen for correct CRS use. These tools could be administered by telephone to obtain a more representative estimate of the prevalence of CRS misuse or to screen for CRS misuse. This screening would assist in targeting time consuming and costly CRS clinics to those parents who need them the most.