Caffeoyl shikimate esterase (CSE) is an enzyme in the lignin biosynthetic pathway in Arabidopsis

Lignin is a major component of plant secondary cell walls. Here we describe caffeoyl shikimate esterase (CSE) as an enzyme central to the lignin biosynthetic pathway. Arabidopsis thaliana cse mutants deposit less lignin than do wild-type plants, and the remaining lignin is enriched in p-hydroxyphenyl units. Phenolic metabolite profiling identified accumulation of the lignin pathway intermediate caffeoyl shikimate in cse mutants as compared to caffeoyl shikimate levels in the wild type, suggesting caffeoyl shikimate as a substrate for CSE. Accordingly, recombinant CSE hydrolyzed caffeoyl shikimate into caffeate. Associated with the changes in lignin, the conversion of cellulose to glucose in cse mutants increased up to fourfold as compared to that in the wild type upon saccharification without pretreatment. Collectively, these data necessitate the revision of currently accepted models of the lignin biosynthetic pathway.

Nature and severity of lung function abnormalities in extremely pre-term children at 11 years of age

Advances in neonatal care have resulted in increased survival of children born extremely pre-term (EP). Nevertheless the incidence of bronchopulmonary dysplasia and long-term respiratory morbidity remains high. We investigated the nature of pathophysiological changes at 11 yrs of age to ascertain whether respiratory morbidity in EP children primarily reflects alterations in the lung periphery or more centralised airway function in this population. Spirometry, plethysmography, diffusing capacity, exhaled nitric oxide, multiple-breath washout, skin tests and methacholine challenge were used during laboratory-based assessments in a subgroup of the 1995 EPICure cohort and in controls. Results were obtained in 49 EP and 52 control children. Lung function abnormalities were found in 78% of EP children, with evidence of airway obstruction, ventilation inhomogeneity, gas trapping and airway hyperresponsiveness. Levels of atopy and exhaled nitric oxide were similar between the groups. Prior wheeze was associated with significant reductions in forced flows and volumes. By contrast, abnormalities of the lung periphery appear to be mediated primarily through EP birth per se. The prevalence of lung function abnormalities, which is largely obstructive in nature and likely to have long-term implications, remains high among 11-yr-old children born EP. Spirometry proved an effective means of detecting these persistent abnormalities.

Delivery of cytoplasmic and apoplastic effectors from Phytophthora infestans haustoria by distinct secretion pathways

The potato blight pathogen Phytophthora infestans secretes effector proteins that are delivered inside (cytoplasmic) or can act outside (apoplastic) plant cells to neutralize host immunity. Little is known about how and where effectors are secreted during infection, yet such knowledge is essential to understand and combat crop disease. We used transient Agrobacterium tumefaciens-mediated in planta expression, transformation of P. infestans with fluorescent protein fusions and confocal microscopy to investigate delivery of effectors to plant cells during infection. The cytoplasmic effector Pi04314, expressed as a monomeric red fluorescent protein (mRFP) fusion protein with a signal peptide to secrete it from plant cells, did not passively re-enter the cells upon secretion. However, Pi04314-mRFP expressed in P. infestans was translocated from haustoria, which form intimate interactions with plant cells, to accumulate at its sites of action in the host nucleus. The well-characterized apoplastic effector EPIC1, a cysteine protease inhibitor, was also secreted from haustoria. EPIC1 secretion was inhibited by brefeldin A (BFA), demonstrating that it is delivered by conventional Golgi-mediated secretion. By contrast, Pi04314 secretion was insensitive to BFA treatment, indicating that the cytoplasmic effector follows an alternative route for delivery into plant cells. Phytophthora infestans haustoria are thus sites for delivery of both apoplastic and cytoplasmic effectors during infection, following distinct secretion pathways.

Diagnosis by AMPLICOR PCR of Chlamydia trachomatis infection in urine samples from women and men attending sexually transmitted disease clinics

Screening of urine specimens from men for Chlamydia trachomatis infection by a commercial PCR assay (AMPLICOR C. trachomatis Test; Roche Diagnostic Systems, Inc., Branchburg, N.J.) is a sensitive and specific noninvasive diagnostic assay. Since screening of women for C. trachomatis infection with the AMPLICOR C. trachomatis Test has been limited to use with endocervical swab specimens, we conducted an evaluation of the AMPLICOR C. trachomatis Test for the detection of C. trachomatis using female urine samples and compared the results of those obtained by in vitro culture and PCR of endocervical swab specimens. For 713 men we compared the performance of AMPLICOR C. trachomatis Test with urine specimens with that of culture of urethral specimens. For specimens that were PCR positive and culture negative, two additional tests were used to resolve the discrepancies: direct fluorescent-antibody assay (DFA) of sediment from a spun endocervical specimen culture vial and major outer membrane protein-based PCR of the sediment from the endocervical specimen culture vial. Of 525 urine specimens from females, 67 (12.8%) were PCR positive, and 41 (7.8%) endocervical specimens from the 525 women were culture positive. After resolution of the discrepancies, the resolved sensitivity of the urine PCR was 93.3%, whereas the sensitivity of endocervical swab specimen culture was 67.3%. Of 468 female endocervical swab specimens, 47 (10.0%) had a positive PCR result and 33 (7.0%) were culture positive. The resolved sensitivity of the endocervical swab specimen PCR was 86%. Of 415 matched female urine and endocervical swab specimens, there were 49 confirmed infections; 30 (61.2%) specimens were positive by culture of the endocervical swab specimen, 40 (81.6%) were positive by confirmed endocervical swab specimen PCR, 43 (87.8%) were positive by confirmed urine PCR, and all 49 (100%) were positive by either endocervical swab specimen PCR or urine PCR. For men, the resolved sensitivity of the urine PCR was 88%, and the sensitivity of culture was only 50.7%. These results indicate that urine PCR is highly sensitive for the detection of C. trachomatis in both women and men and provides a noninvasive technique for routine screening for chlamydial infection.

Hip bone mineral density is improved by high-impact aerobic exercise in postmenopausal women and men over 50 years

Fifteen men and women (six men) between the ages of 50 and 73 years were recruited to begin keep-fit classes. They were matched for sex, age, menopausal status and mass to 15 non-exercising controls. The keep-fit classes were two to three times a week and included high-impact exercise, including step and jumping exercises specifically to load the proximal femur and spine. Proximal femur, lumbar spine and total body bone mineral density (BMD) were measured at 0 and 12 months. Urinary pyridinoline (Pyr) and deoxypyridinoline (dPyr) crosslinks were measured every 6 months to assess bone resorption. Quadriceps isometric strength was measured every 6 months. BMD increased non-significantly at the femoral neck [1.57 (0.8)%] and Wards triangle [1.97 (1.4)%], and significantly at the greater trochanter 2.21 (0.9)% (P = 0.02) in the exercise group. Femoral neck BMD decreased by -1.9(0.8)% (P = 0.049) in the control group, which was significantly different from the change in the exercise group (P = 0.009). BMD did not change at the Wards triangle or trochanter in the controls. Lumbar spine BMD did not change in either group. Total body BMD did not change in the exercise group, but decreased by -0.79 (0.3)% (P = 0.02) in the controls. Following 6 months of the exercise classes. Pyr and dPyr crosslinks were significantly reduced [-19.0 (7.2)%; P = 0.0019 and -20.0 (7.7)%; P = 0.021 respectively]. There was no significant change in crosslinks after 1 year, and no change at any time in the controls. Quadriceps strength changed by 5.4 (3.7)% in the exercise group and by -6.9 (2.5)% (P = 0.01) in the control group after 12 months, being significant between groups (P = 0.008). This study suggests that high-impact, aerobic exercise in postmenopausal women and men over 50 years old is feasible and effective at maintaining muscle strength and increasing proximal femur BMD but not spine or total body BMD.

The acute effects of exercise on bone turnover

Exercise is known to have long-term benefits on bone mass, but little is known about the short-term effects of exercise on bone turnover. The purpose of this study was to investigate whether acute effects of exercise on bone remodelling could be detected by measuring blood and urinary markers of bone turnover. We measured biochemical markers of bone turnover in ten healthy, young men before and up to 32 hours after 30 minutes of brisk treadmill walking. Blood samples were taken before, immediately after and at 0.5, 1, 8, 24 and 32 hours after the exercise. These were assayed for osteocalcin and bone specific alkaline phosphatase. Twenty-four hour urine samples were taken over three days (day before, day of and day after exercise) and measured for pyridinoline and deoxypyridinoline crosslinks. Crosslink excretion was standardised for total body bone mineral content (TBBMC) and urinary creatinine. Total body bone mineral density (and content) and body composition were measured by dual energy X-ray absorptiometry. No changes in the levels of either osteocalcin or alkaline phosphatase were seen at any time point following the exercise. Both urinary crosslinks exhibited an increase in levels on the day of the exercise and a further significant increase the day after (pyridinoline 38.7%, p = 0.05; deoxypyridinoline 42.3%, p = 0.025; median, corrected for TBBMC). There were significant negative correlations between the crosslinks, osteocalcin and body fat percentage. In conclusion, the exercise appears to have stimulated bone resorption within 32 hours of moderate exercise, but there was no measurable effect on bone formation after 32 hours. A longer study period may be necessary to detect changes in bone formation.

RXLR Effector AVR2 Up-Regulates a Brassinosteroid-Responsive bHLH Transcription Factor to Suppress Immunity

An emerging area in plant research focuses on antagonism between regulatory systems governing growth and immunity. Such cross talk represents a point of vulnerability for pathogens to exploit. AVR2, an RXLR effector secreted by the potato blight pathogen Phytophthora infestans, interacts with potato BSL1, a putative phosphatase implicated in growth-promoting brassinosteroid (BR) hormone signaling. Transgenic potato (Solanum tuberosum) plants expressing the effector exhibit transcriptional and phenotypic hallmarks of overactive BR signaling and show enhanced susceptibility to P. infestans Microarray analysis was used to identify a set of BR-responsive marker genes in potato, all of which are constitutively expressed to BR-induced levels in AVR2 transgenic lines. One of these genes was a bHLH transcription factor, designated StCHL1, homologous to AtCIB1 and AtHBI1, which are known to facilitate antagonism between BR and immune responses. Transient expression of either AVR2 or CHL1 enhanced leaf colonization by P. infestans and compromised immune cell death activated by perception of the elicitin Infestin1 (INF1). Knockdown of CHL1 transcript using Virus-Induced Gene Silencing (VIGS) reduced colonization of P. infestans on Nicotiana benthamiana Moreover, the ability of AVR2 to suppress INF1-triggered cell death was attenuated in NbCHL1-silenced plants, indicating that NbCHL1 was important for this effector activity. Thus, AVR2 exploits cross talk between BR signaling and innate immunity in Solanum species, representing a novel, indirect mode of innate immune suppression by a filamentous pathogen effector.

Reference equations for specific airway resistance in children: the Asthma UK initiative

Plethysmographic specific airway resistance (sR(aw)) is a useful research method for discriminating lung disease in young children. Its use in clinical management has, however, been limited by lack of consensus regarding equipment, methodology and reference data. The aim of our study was to collate reference data from healthy children (3-10 yrs), document methodological differences, explore the impact of these differences and construct reference equations from the collated dataset. Centres were approached to contribute sR(aw) data as part of the Asthma UK initiative. A random selection of pressure-flow plots were assessed for quality and site visits elucidated data collection and analysis protocols. Five centres contributed 2,872 measurements. Marked variation in methodology and analysis excluded two centres. sR(aw) over-read sheets were developed for quality control. Reference equations and recommendations for recording and reporting both specific effective and total airway resistance (sR(eff) and sR(tot), respectively) were developed for White European children from 1,908 measurements made under similar conditions. Reference sR(aw) data collected from a single centre may be misleading, as methodological differences exist between centres. These preliminary reference equations can only be applied under similar measurement conditions. Given the potential clinical usefulness of sR(aw), particularly with respect to sR(eff), methodological guidelines need to be established and used in prospective data collection.

The EPICure study: comparison of pediatric spirometry in community and laboratory settings

RATIONALE

Accuracy of spirometry testing is a prerequisite for its use as an objective outcome measure in large epidemiological studies. We compared spirometry measurements obtained by trained pediatricians in a variety of school settings with those obtained in the laboratory by respiratory physiologists.

METHODS

Following a 3-day training course, three pediatricians carried out spirometry in children born extremely preterm (EP) and age matched controls in schools across the UK and Ireland (The EPICure study). A subgroup had repeated measurements in the laboratory. Spirometric flows and volumes were expressed as Z-scores. Bland-Altman analysis was used to calculate within-subject differences.

RESULTS

Fifty children (40% boys), 37 (74%) of whom were born EP, with a mean age 10.8 years had paired spirometry results (average interval between tests: 20.3 weeks). There was no statistically significant difference between any of the outcome variables: mean (95% CI of difference) in Z-scores [school-laboratory]) being 0.0 (-0.1; 0.1) for FEV(1), 0.1 (-0.1; 0.3) for FVC, -0.1 (-0.3; 0.1) for FEF(25-75), and 0.0 (-0.3; 0.1) for FEV(1)/FVC. Within individuals, the 95% limits of agreement for repeated measures were within +/- 1 Z-score for FEV(1) and FVC, and within +/- 1.5 Z-score for FEF(25-75) and FEV(1)/FVC.

CONCLUSION

With appropriate training, quality control, and support, pediatric spirometry can reliably be performed outside the lung function laboratory.

Effects of isometric strength training on quadriceps muscle properties in over 55 year olds

Changes in strength, speed and size of the quadriceps muscle have been investigated in elderly men and women after 6 months of isometric strength training. We have also indirectly investigated the role of metabolites as a stimulus for muscle hypertrophy by studying two training protocols. One thigh was trained using short, intermittent contractions (IC), while the other trained using long, continuous contractions (CC). This meant that there should be a greater metabolite change in the muscle performing CC, as the blood flow is occluded for longer. Nine subjects [eight women, mean (SE) age, 71.8 (2.9) years] were measured for contractile properties and strength before and after training, and compared to nine age-matched controls [71.5 (2.1) years]. The training group increased quadriceps strength by 48.7 (9.1)% (P < 0.005) and 53.1 (11.3)% (P < 0.005) following the IC and CC protocols, respectively. There was no change in muscle strength in the controls. Both muscles showed significant slowing after training as measured by the relaxation times and the force-frequency ratio. There were non-significant decreases in muscle fatigability after training. The control group also showed some significant decreases in fatigability and muscle speed. The training group showed significant increases in muscle (and bone) cross-sectional area of 4.0 (1.7)% and 4.9 (1.3)% following the CC and IC protocols, respectively. These increases were significantly different from the decrease observed in the control group. These findings suggest that people over the age of 55 still have the capacity to increase muscle strength and size, and that the training causes slowing of the muscle. Muscle hypertrophy does not seem to be strongly influenced by metabolite changes in this age group, as there were no differences in measurements observed between protocols.

In vitro activities of azithromycin, clarithromycin, erythromycin, and tetracycline against 13 strains of Chlamydia pneumoniae

Thirteen strains of Chlamydia pneumoniae were evaluated for their in vitro susceptibilities to azithromycin, clarithromycin, erythromycin, and tetracycline. The MIC ranges were 0.125 to 0.5 micrograms/ml for azithromycin, 0.031 to 1.0 micrograms/ml for clarithromycin, 0.125 to 1.0 micrograms/ml for erythromycin, and 0.25 to 1.0 micrograms/ml for tetracycline. The ranges for the minimal lethal concentrations were 0.125 to 0.5 micrograms/ml for azithromycin, 0.031 to 1.0 micrograms/ml for clarithromycin, 0.125 to 1.0 micrograms/ml for erythromycin, and 0.25 to 1.0 micrograms/ml for tetracycline. Clarithromycin and azithromycin were the most active antibiotics against C. pneumoniae in vitro.

AVR2 Targets BSL Family Members, Which Act as Susceptibility Factors to Suppress Host Immunity

To be successful plant pathogens, microbes use "effector proteins" to manipulate host functions to their benefit. Identifying host targets of effector proteins and characterizing their role in the infection process allow us to better understand plant-pathogen interactions and the plant immune system. Yeast two-hybrid analysis and coimmunoprecipitation were used to demonstrate that the Phytophthora infestans effector AVIRULENCE 2 (PiAVR2) interacts with all three BRI1-SUPPRESSOR1-like (BSL) family members from potato (Solanum tuberosum). Transient expression of BSL1, BSL2, and BSL3 enhanced P. infestans leaf infection. BSL1 and BSL3 suppressed INFESTIN 1 elicitin-triggered cell death, showing that they negatively regulate immunity. Virus-induced gene silencing studies revealed that BSL2 and BSL3 are required for BSL1 stability and show that basal levels of immunity are increased in BSL-silenced plants. Immune suppression by BSL family members is dependent on the brassinosteroid-responsive host transcription factor CIB1/HBI1-like 1. The P. infestans effector PiAVR2 targets all three BSL family members in the crop plant S. tuberosum These phosphatases, known for their role in growth-promoting brassinosteroid signaling, all support P. infestans virulence and thus can be regarded as susceptibility factors in late blight infection.

Drug treatment of essential hypertension: the case for initial combination therapy

Essential hypertension is a major cause of cardiovascular morbidity and mortality in the Western world, yet it remains poorly controlled. Single drug-antihypertensive therapy is unsuccessful in up to half of all patients with hypertension; although lack of adherence may account for a proportion of this, there is evidence of considerable variation in the response of different hypertensive patients to different drug classes. A number of algorithms have been proposed in the literature, with a view to predicting an individual's response to different antihypertensive agents. However, even using such algorithms, hypertension control remains problematic, and they are frequently difficult to apply in everyday clinical practice. Initiation of treatment with low-dose combination antihypertensive therapy, using a drug which reduces total body sodium and/or volume in combination with a drug which blocks the renin-angiotensin system, provides an effective and easily applicable means to improve hypertension control in the primary care setting.

Multicenter evaluation of the AntigEnz Chlamydia enzyme immunoassay for diagnosis of Chlamydia trachomatis genital infection

To evaluate the AntigEnz Chlamydia enzyme immunoassay (EIA) (Baxter/Bartels, Issaquah, Wash.), we studied 320 men and 1,209 women attending clinics for sexually transmitted diseases in Baltimore, San Francisco, and Seattle. At examination, two separate swabs were obtained from each patient, one for chlamydial culture and one for EIA. Cervical samples were collected from women, and urethral samples were collected from men. The prevalence of chlamydial infection by culture was 9% in Baltimore (n = 532), 11% in Seattle (n = 500), and 9% in San Francisco (n = 497). To resolve specimens with discrepant culture and EIA results, the EIA transport buffer was centrifuged and the resuspended pellet was stained by direct immunofluorescence to determine whether elementary bodies were present. Overall sensitivity of the AntigEnz Chlamydia assay compared with culture was 87% in men and 86% in women, and overall specificities were 94 and 97%, respectively. Differences between centers were seen, with sensitivities ranging from 76% among men and 79% among women in Seattle to 100% among men and 95% among women in Baltimore. With a true positive considered to be either a culture-positive or an EIA- and direct immunofluorescence-positive specimen, the revised sensitivity was 91% in men and 88% in women. Overall revised specificity was 99% in both men and women. We conclude that in this high-prevalence population, the sensitivity and specificity of this assay compare favorably with those of other noncultural antigen detection tests for the diagnosis of chlamydial genital infection.

Stereotactic radiosurgery planning of vestibular schwannomas: Is MRI at 3 Tesla geometrically accurate?

Purpose

MRI is a mandatory requirement to accurately plan Stereotactic Radiosurgery (SRS) for Vestibular Schwannomas. However, MRI may be distorted due not only to inhomogeneity of the static magnetic field and gradients but also due to susceptibility‐induced effects, which are more prominent at higher magnetic fields. We assess geometrical distortions around air spaces and consider MRI protocol requirements for SRS planning at 3 T.

Methods

Hardware‐related distortion and the effect of incorrect shimming were investigated with structured test objects. The magnetic field was mapped over the head on five volunteers to assess susceptibility‐related distortion in the naso‐oro‐pharyngeal cavities (NOPC) and around the internal ear canal (IAC).

Results

Hardware‐related geometric displacements were found to be less than 0.45 mm within the head volume, after distortion correction. Shimming errors can lead to displacements of up to 4 mm, but errors of this magnitude are unlikely to arise in practice. Susceptibility‐related field inhomogeneity was under 3.4 ppm, 2.8 ppm, and 2.7 ppm for the head, NOPC region and IAC region, respectively. For the SRS planning protocol (890 Hz/pixel, approximately 1 mm³ isotropic), susceptibility‐related displacements were less than 0.5 mm (head), and 0.4 mm (IAC and NOPC). Large displacements are possible in MRI examinations undertaken with lower receiver bandwidth values, commonly used in clinical MRI. Higher receiver bandwidth makes the protocol less vulnerable to sub‐optimal shimming. The shimming volume and the CT‐MR co‐registration must be considered jointly.

Conclusion

Geometric displacements can be kept under 1 mm in the vicinity of air spaces within the head at 3 T with appropriate setting of the receiver bandwidth, correct shimming and employing distortion correction.

Host recognition of fetal antigens: do they induce specific antibodies?

The purpose of this study was to ascertain whether the protection afforded to adult mice against the induction and growth of 3-methylcholanthrene-induced tumours by prior exposure to syngeneic fetal cells has an immunological basis. Adult CBA mice were inoculated with fetal cells according to a variety of protocols and the sera were tested for their ability to bind to fetal and adult tissue cells, using a staphylococcal protein A binding assay. All 10 sera tested showed some degree of binding though this varied from strong to weak, and there was some cross-reactivity with adult thymic cells but relatively little with adult spleen cells. Absorption studies were carried out with one of these sera and with two others raised against testicular and thymic cells, respectively. The absorption patterns obtained so far suggest that fetal cells possess at least three, and possibly up to five, distinct antigens. Although none of the anti-fetal sera were produced with a sensitizing protocol identical with that used in in vivo protection, some of them were so close as to suggest that protection is associated with, and perhaps causally related to, these IgG antibodies. The in vitro evidence presented here, together with the in vivo data of P. B. Medawar & R. Hunt, shows that antigens are shared between fetal cells and adult thymic and testicular cells. It therefore lends support to the notion that the production of a vaccine against anaplastic neoplasms, using immunogens derived from adult tissues, is within the realms of possibility.