Impact of subsoil water use on wheat yield

Water stored deep in the soil profile is generally considered valuable to crop yield because it becomes available during grain filling, but the value of subsoil water for grain yield has not been isolated and quantified in the field. We used rainout shelters with irrigation to control the water supply to wheat crops that had different amounts of subsoil water available to isolate and quantify the efficiency with which the subsoil water was converted to grain yield. Under moderate post-anthesis stress, 10.5 mm of additional subsoil water used in the 1.35–1.85 m layer after anthesis increased grain yield by 0.62 t/ha, representing an efficiency of 59 kg/ha.mm. The additional yield resulted from a period of higher assimilation 12–27 days after anthesis and was related to an increase in grain size rather than other yield components. Under more severe stress with earlier onset, extra water use below 1.25 m was accompanied by additional water use in upper soil layers and it was more difficult to isolate and quantify the benefit of deep water to grain yield. The additional water used from all layers from the time the stress was imposed was converted to grain at 30–40 kg/ha.mm, but this increased to 60 kg/ha.mm for water used after anthesis. The high efficiency for subsoil water use is 3 times that typically expected for total seasonal water use, and twice that previously estimated for total post-anthesis water use in a similar environment. The results demonstrate that relatively small amounts of subsoil water can be highly valuable to grain yield.

A prospective randomized controlled trial evaluating alcohol on loudness perception in cochlear implant users

AIM

The aim of this study was to determine the effects of alcohol on the psychophysical responses in patients with cochlear implants. This has not been previously studied. It was also hoped to provide information that could suggest possible sites of action of the known effects of alcohol on the auditory pathway.

DESIGN

A prospective randomized placebo-controlled trial, with full ethical approval.

PARTICIPANTS

Eight successful cochlear implant users were selected, of whom two had bilateral implants which were tested separately. In total 10 cochlear implants were tested.

INTERVENTION

Alcohol was given in the form of vodka (50% alcohol, 1 mL/kg body weight) with 500 mL of orange and cranberry juice. The placebo control was given in the form of 500 mL of orange and cranberry juice alone.

OUTCOME MEASUREMENT

The 'comfort level' (C level) was recorded before, and 1 h after alcohol or placebo ingestion for each patient's cochlear implant. Blood alcohol concentration was determined prior to alcohol or placebo consumption and then repeated after 45, 60, 90 and 180 min.

RESULTS

The mean blood alcohol concentration 1 h after ingestion was 50 mg/dL. In the 'alcohol' arm the mean electrical unit increase in the C level was 19.9 with a standard deviation of 2.2. In the control arm the mean change in C level was 0.10 with a standard deviation of 0.3.

CONCLUSIONS

In this first prospective randomized control study of the effect of alcohol on sound perception in cochlear implant users, alcohol significantly increased the upper end of the dynamic range (C levels) in comparison with placebo (P = <0.0001 using paired t-test analysis). This effect is likely to be the result of change in the auditory pathways proximal to the cochlea.

A comparison of the analgesic efficacy and side-effects of paravertebral vs epidural blockade for thoracotomy--a systematic review and meta-analysis of randomized trials

Epidural analgesia is considered by many to be the best method of pain relief after major surgery. It is used routinely in many thoracic surgery centres. Although effective, side-effects include hypotension, urinary retention, incomplete (or failed) block, and, in rare cases, paraplegia. Paravertebral block (PVB) is an alternative technique that may offer comparable analgesic effectiveness and a better side-effect profile. We undertook a systematic review and meta-analysis of all relevant randomized trials comparing PVB with epidural analgesia in thoracic surgery. Data were abstracted and verified by both authors. Studies were tested for heterogeneity, and meta-analyses were done with random effects or fixed effects models. Weighted mean difference (WMD) was used for numerical outcomes and odds ratio (OR) for dichotomous outcomes, both with 95% CI. We identified 10 trials that had enrolled 520 thoracic surgery patients. All of the trials were small (n<130) and none were blinded. There was no significant difference between PVB and epidural groups for pain scores at 4-8, 24 or 48 h, WMD 0.37 (95% CI: -0.5, 121), 0.05 (-0.6, 0.7), -0.04 (-0.4, 0.3), respectively. Pulmonary complications occurred less often with PVB, OR 0.36 (0.14, 0.92). Urinary retention, OR 0.23 (0.10, 0.51), nausea and vomiting, OR 0.47 (0.24, 0.53), and hypotension, OR 0.23 (0.11, 0.48), were less common with PVB. Rates of failed block were lower in the PVB group, OR 0.28 (0.2, 0.6). PVB and epidural analgesia provide comparable pain relief after thoracic surgery, but PVB has a better side-effect profile and is associated with a reduction in pulmonary complications. PVB can be recommended for major thoracic surgery.

The adult phenotype in Costello syndrome

We report clinical findings in 17 adults with Costello syndrome ranging in age from 16 to 40 years. Two patients in this series have had bladder carcinoma, the only malignancy reported to affect adults with Costello syndrome. Benign tumors included multiple ductal papillomata in two women, and a fourth ventricle mass in one man, thought to be a choroid plexus papilloma. Endocrine problems in this series were osteoporosis, central hypogonadism, and delayed puberty. Other health problems were symptomatic Chiari malformations in three patients. Four patients had adult-onset gastro-esophageal reflux, three of whom had Chiari malformations. Fourteen adults had mild to moderate intellectual disability with three individuals having severe intellectual disability; 15 individuals attained some reading and writing skills and 14 showed ongoing acquisition of new skills into adulthood. On the basis of this data, we recommend that neuro-imaging be considered in adults with Costello syndrome if they develop symptoms suggestive of a Chiari malformation. In the event of pubertal delay, endocrine investigations are indicated and hormone treatment may be required. Bone density assessments should be performed in adults with Costello syndrome, particularly in those with pubertal abnormalities. Screening for microscopic hematuria as a marker for bladder carcinoma may be indicated, although this requires further evaluation.

Incidence of meningitis and of death from all causes among users of cochlear implants in the United Kingdom

BACKGROUND

During 2002, there was an increase in reports of bacterial meningitis among people with cochlear implants in Europe and North America. One model of implant, which included a space-occupying 'positioner', was recalled. Implantation of a positioner was shown to be a risk factor for meningitis among children in the United States. The situation in the United Kingdom was not known.

METHODS

We ascertained the cohort of people who had received cochlear implants with intra-cochlear electrodes in UK hospitals prior to 1 October 2002 and were permanently resident in the United Kingdom. We compared the incidence of meningitis, and the causes and incidence of death from all causes, between the cohort and reference populations.

RESULTS

Of 1851 children (66 with positioners), none had contracted meningitis. Neither the incidence rate of meningitis, nor the cumulative mortality from all causes, differed significantly between implanted children and values expected for the general population. Of 1779 adults (139 with positioners), five had contracted meningitis with three fatalities. No case of meningitis involved a positioner and four of the cases, including the fatalities, possessed risk factors unrelated to implantation. Although the incidence rate of meningitis was significantly higher in implanted adults than the general population, cumulative mortality from all causes was never higher, and was significantly lower at some time points after implantation.

CONCLUSION

Specific evidence of the association between bacterial meningitis and implantation with a positioner that arose in the United States and mainland Europe during 2002 has not been found in the United Kingdom.

Diffusion tensor imaging for the assessment of upper motor neuron integrity in ALS

BACKGROUND

High angular resolution diffusion tensor imaging (HARD) is an MRI technique that exploits the mobility of water molecules to yield maps of structural order and directionality of white matter tracts with greater precision than six-direction diffusion tensor imaging (DTI) schemes.

OBJECTIVE

To assess whether HARD is more sensitive than conventional MRI or neurologic assessment in detecting the upper motor neuron (UMN) pathology of patients with ALS.

METHODS

Twenty-five patients with definite UMN clinical signs and 23 healthy volunteers underwent conventional MRI. HARD datasets were collected from a subset of these participants plus four patients with isolated lower motor neuron (LMN) signs. ALS symptom severity was assessed by a neurologist, the conventional MR images were reviewed by neuroradiologists, and the DTI maps were subject to quantitative region of interest analysis.

RESULTS

Motor cortex hypointensity on T2-weighted images and corona radiata hyperintensity on proton density-weighted images distinguished patients with UMN involvement from volunteers with 100% specificity, but only 20% sensitivity. Fractional anisotropy (FA) was reduced in the posterior limb of the internal capsule in patients with UMN involvement compared to volunteers. A FA threshold value with a sensitivity of 95% to detect patients with ALS (including those with isolated LMN signs) had a specificity of 71%.

CONCLUSIONS

High angular resolution diffusion tensor imaging may be more sensitive than conventional MRI or neurologic assessment to the upper motor neuron (UMN) pathology of ALS, but it lacks the specificity required of a diagnostic marker. Instead, it is potentially useful as a quantitative tool for monitoring the progression of UMN pathology.

Annual patterns in bacterioplankton community variability in a humic lake

Bacterioplankton community composition (BCC) was monitored in a shallow humic lake in northern Wisconsin, USA, over 3 years using automated ribosomal intergenic spacer analysis (ARISA). Comparison of ARISA profiles of bacterial communities over time indicated that BCC was highly variable on a seasonal and annual scale. Nonmetric multidimensional scaling (MDS) analysis indicated little similarity in BCC from year to year. Nevertheless, annual patterns in bacterioplankton community diversity were observed. Trends in bacterioplankton community diversity were correlated to annual patterns in community succession observed for phytoplankton and zooplankton populations, consistent with the notion that food web interactions affect bacterioplankton community structure in this humic lake. Bacterioplankton communities experience a dramatic drop in richness and abundance each year in early summer, concurrent with an increase in the abundance of both mixotrophic and heterotrophic flagellates. A second drop in richness, but not abundance, is observed each year in late summer, coinciding with an intense bloom of the nonphagotrophic dinoflagellate Peridinium limbatum. A relationship between bacterial community composition, size, and abundance and the population dynamics of Daphnia was also observed. The noted synchrony between these major population and species shifts suggests that linkages across trophic levels play a role in determining the annual time course of events for the microbial and metazoan components of the plankton.

The effects of arbuscular mycorrhizas on soil aggregation depend on the interaction between plant and fungal species

•  Arbuscular mycorrhizal fungi (AMF) and roots mediate soil stabilization, although the mechanisms and how their interactions affect soil stabilization are not known. We tested the effects of specific plant-fungus combinations on aggregate stabilization, and whether hyphal length and root biomass determine stabilization, predicting that fungi producing more hyphae, and plants with higher root biomasses, would better stabilize soils. •  The percentage of water-stable aggregates (%WSA_1-2 mm ), hyphal lengths, and root biomass were measured from a five AMF × nine plant factorial experiment. Arbuscular mycorrhizal fungi with greater extradical mycelium production were represented by the Gigasporaceae and plants of high root biomass by grasses. Other taxa represented lower hyphal lengths and root biomass. •  An interaction between symbionts with respect to %WSA_1-2 mm was observed. Root biomass and total hyphal lengths were not positively correlated with %WSA. Combinations of grasses with Gigasporaceae fungi had the lowest %WSA. •  Mechanisms underlying aggregation were not elucidated by measuring root biomass and total hyphal lengths alone, suggesting other physiological or architectural mechanisms may be responsible.

Seasonal dynamics of phytoplankton and planktonic protozoan communities in a northern temperate humic lake: diversity in a dinoflagellate dominated system

Species diversity and richness, and seasonal population dynamics of phytoplankton, planktonic protozoa, and bacterioplankton sampled from the epilimnion of Crystal Bog in 2000, were examined in order to test the hypothesis that these groups' diversity and abundance patterns might be linked. Crystal Bog, a humic lake in Vilas County, Wisconsin, is part of the North Temperate Lakes Long-Term Ecological Research Site. Phytoplankton and planktonic protozoa were identified and enumerated in a settling chamber with an inverted microscope. Bacterial cells were enumerated with the use of fluorescence 4', 6'-diamidino-2-phenylindole (DAPI)-staining procedures, and automated ribosomal intergenic spacer analysis (ARISA) was used to assess bacterioplankton diversity. Bacterial cell counts showed little seasonal variation and averaged 2.6 x 10(6) cells/mL over the ice-free season. Phytoplankton and planktonic protozoan numbers varied by up to two orders of magnitude and were most numerous in late spring and summer. Dinoflagellates largely dominated Crystal Bog throughout the ice-free period, specifically Peridiniopsis quadridens in the spring, Peridinium limbatum in summer, and Gymnodinium fuscum and P. quadridens in fall. Brief blooms of Cryptomonas, Dinobryon, and Synura occurred between periods of dinoflagellate domination. The dominant dinoflagellate, Peridinium limbatum, was calculated to have a growth rate of 0.065 day(-1) and a doubling time of 10.7 days. Heterotrophic nanoflagellates (HNFs) were a consistent component of the planktonic protozoa; seasonal patterns were determined for three genera of HNFs (Monosiga, Bicosoeca, and Desmarella moniliformis). Three genera of ciliates (Coleps, Strobilidium, and Strombidium) comprised the greater part of the planktonic protozoa in Crystal Bog. The number of species of planktonic protozoa was too low to calculate a diversity index. Shannon-Weaver diversity indices for phytoplankton and bacterioplankton in the epilimnion followed very similar seasonal patterns in this lake, supporting the hypothesis that in freshwaters, diversity patterns of these groups are linked.

A novel retractor for use in cochlear implantation

A new self-retaining scalp retractor is described, which elevates the scalp away from the skull to allow better access and vision in preparing the bony recess for a cochlear implant and protect the pericranium from surgical trauma. It is designed for use with the present generation of small vertical scalp incisions in cochlear implant surgery. In these incisions, the part of the skull drilled to create the implant bed is not directly under the wound; instead, it extends under a flap of scalp and pericranium for 5 cm or more. The retractor is simple to use, and the authors believe that it represents a new type of retractor, which may have other uses in the fields of orthopedic; ear, nose, and throat, cosmetic, and plastic surgery. Photographs demonstrate the instrument in use. A cochlear implant company has agreed to manufacture the instrument.

Fractionation of lipoprotein subclasses in self-generated gradients of iodixanol

Chapter 5 described the use of self-generated gradients of iodixanol for the fractionation of human plasma lipoproteins into the major classes: high-density, low-density, and very low density (HDL, LDL, and VLDL). During the metabolism of plasma HDL and LDL, the lipid and apoprotein composition of the lipoprotein particles changes in such a manner that a series of subclasses exists, each with a distinctive range of densities (1). Thus, in KBr gradients, the two major subclasses, HDL(2) and HDL(3), have densities of 1.063-1.125 g/mL and 1.125-1.21 g/mL, respectively (1). In some individuals a third subclass (HDL1) is recognized (1.055-1.063 g/mL). Electrophoretic (2) and immunological (3,4) techniques have identified additional subfractions. Likewise, subclasses of LDL have been identified and isolated using shallow KBr gradients (5,6). The major LDL subfractions are LDL(1), LDL(2), and LDL(3), which have densities of 1.025-1.034 g/mL, 1.034-1.044 g/mL, and 1.044-1.060 g/mL, respectively (6), and electrophoretic analysis has identified more subfractions (7). The subfractions of LDL are of particular interest, as the presence of small, dense LDL particles in the plasma appears to be associated with a predisposition to cardiovascular disease, and they are recognized as a major causative factor in atherosclerosis (8). Methods for monitoring the LDL subclass pattern in population studies and in dietary and drug intervention trials are thus of considerable interest. This chapter is concerned primarily with the subfractionation of LDL. Although HDL subfractionation systems using iodixanol self-generated gradients have not yet been validated by direct comparison with other methods (e.g., gradient gel electrophoresis or KBr gradient centrifugation), a protocol is included.

Effects of insulin lispro and chronic vitamin C therapy on postprandial lipaemia, oxidative stress and endothelial function in patients with type 2 diabetes mellitus

BACKGROUND

Insulin therapy may influence cardiovascular disease (CVD) and lipid metabolism in type 2 diabetes (T2D). Exaggerated postprandial lipaemia (PPL) is a feature of diabetic dyslipidaemia affecting CVD via enhanced oxidative stress (OS) and endothelial dysfunction. We assessed endothelial function and OS during PPL following insulin and vitamin C. Twenty (17 M) T2D patients were studied (mean Hba1c 8.4%) at baseline, following 6 weeks of insulin lispro (0.2 Iu kg-1) and vitamin C 1-g daily. Eight-h lipid and glucose profiles were measured following a fatty meal. Endothelial function (flow-mediated vasodilatation: FMD) and OS were measured at fasting, 4 h and 8 h.

MATERIALS AND METHODS

Glucose, body mass index, and total and LDL cholesterol remained unchanged. FMD improved. Placebo group: fasting, 1.1 +/- 1.2 to 4.2 +/- 1.1% (P < 0.001); 4-h, 0.3 +/- 1.2 to 3.1 +/- 0.9% (P < 0.01); 8-h, 0.7 +/- 1.1 to 3.76 +/- 1.1% (P < 0.001). Vitamin C group: fasting, 0.9 +/- 1.1 to 6.1 +/- 1.3% (P < 0.001); 4-h, 0.7 +/- 1.5 to 4.9 +/- 2.1% (P < 0.001); 8-h, 0.8 +/- 0.9 to 5.8 +/- 0.6% (P < 0.01). Post-prandial lipaemia was attenuated: TG area-under-curve (mmol L-1 8 h-1), 52.6 +/- 11 to 39.1 +/- 12.5 (placebo group), P < 0.02; and 56.9 +/- 8 to 40.1 +/- 10.3 (vitamin C group), P < 0.02. Oxidative stress was reduced, with greater changes in the vitamin C group.

CONCLUSION

Insulin may thus exert vascular benefits in T2D, by modifying fasting and postprandial lipid metabolism resulting in reduced OS and improved EF. Vitamin C therapy may augment the vascular benefits of insulin in T2D through additional effects on OS and EF.

Cochlear implantation in Jervell and Lange-Nielsen syndrome

A case of familial prolonged QT interval and congenital sensorineural hearing loss is described emphasising the diagnostic and management implications. Jervell and Lange-Nielsen syndrome is important because of its potential association with sudden death in children with congenital sensorineural deafness. It is known to be associated with mutations of the genes KCNQ1 (KVQTI) and KCNE1 (Isk). The underlying molecular abnormality leads to cardiac and cochlear dysfunction through a potassium channel defect. All children with congenital sensorineural hearing loss who have suffered unexplained syncopal attacks or convulsions should be screened for this syndrome. There is also a strong case for including a 12 lead ECG as part of the investigative work up of all children with congenital sensorineural deafness in whom a firm aetiology has not been established.

Klinefelter syndrome and its variants: an update and review for the primary pediatrician

Klinefelter syndrome is the most common chromosomal abnormality in humans. Recent prospective, unbiased studies have clarified many of the previous misconceptions associated with Klinefelter syndrome, thereby improving our recognition and management of this condition for affected individuals. The primary-care physician has an important role in caring for these individuals and their families by providing anticipatory guidance regarding issues relating to endocrinology, behavior, development, and preventive medical care. Furthermore, the primary-care giver can serve as a valuable source of support and advocacy for the family of a boy with Klinefelter syndrome. We review the current state of knowledge regarding Klinefelter syndrome and its variants, with an emphasis on medical and early developmental interventions.

Scanning for telomeric deletions and duplications and uniparental disomy using genetic markers in 120 children with malformations

We screened 120 children with sporadic multiple congenital anomalies and either growth or mental retardation for uniparental disomy (UPD) or subtelomeric deletions. The screening used short tandem repeat polymorphisms (STRP) from the subtelomeric regions of 41 chromosome arms. Uninformative marker results were reanalyzed by using the next available marker on that chromosome arm. In total, approximately 25,000 genotypes were generated and analyzed for this study. Subtelomeric deletions of 1 Mb in size were excluded for 27 of 40 chromosome arms. Among the 120 subjects none was found to have UPD, but five subjects (4%, 95% confidence interval 1-9%) were found to have a deletion or duplication of one or more chromosome arms. We conclude that UPD is not a frequent cause of undiagnosed multiple congenital anomaly syndrome. In addition, we determined that 9p and 7q harbor chromosome length variations in the normal population. We conclude that subtelomeric marker analysis is effective for the detection of subtelomeric duplications and deletions, although it is labor intensive. Given a detection rate that is similar to prior studies and the large workload imposed by STRPs, we conclude that STRPs are an effective, but impractical, approach to the determination of segmental aneusomy given current technology.

Syndromic ear anomalies and renal ultrasounds

OBJECTIVE

Although many pediatricians pursue renal ultrasonography when patients are noted to have external ear malformations, there is much confusion over which specific ear malformations do and do not require imaging. The objective of this study was to delineate characteristics of a child with external ear malformations that suggest a greater risk of renal anomalies. We highlight several multiple congenital anomaly (MCA) syndromes that should be considered in a patient who has both ear and renal anomalies.

METHODS

Charts of patients who had ear anomalies and were seen for clinical genetics evaluations between 1981 and 2000 at Cedars-Sinai Medical Center in Los Angeles and Dartmouth-Hitchcock Medical Center in New Hampshire were reviewed retrospectively. Only patients who underwent renal ultrasound were included in the chart review. The literature was reviewed for the epidemiology of renal anomalies in the general population and in MCA syndromes with external ear anomalies. We defined a child as having an external ear anomaly when he or she had any of the following: preauricular pits and tags; microtia; anotia; or cup, lop, and other forms of dysplastic ears. A child was defined as having a renal anomaly if an ultrasound revealed any of the following: unilateral or bilateral renal agenesis; hypoplasia; crossed ectopia; horseshoe, pelvic, cystic kidney; hydronephrosis; duplicated ureters; megaureter; or vesicoureteric reflux.

RESULTS

Because clinical genetics assessments were made by the same clinician at both sites (J.M.G.), data were combined. A total of 42 patients with ear anomalies received renal ultrasound; 12 (29%) of them displayed renal anomalies. Of the 12 patients with renal anomalies, 11 (92%) also received a diagnosis of MCA syndrome. Eleven of 33 patients (33%) with MCA syndromes had renal anomalies, whereas 1 of 9 patients (11%) with isolated ear anomalies had renal anomalies. Specific disorders seen were CHARGE association, Townes-Brocks syndrome, branchio-oto-renal syndrome, Nager syndrome, and diabetic embryopathy.

CONCLUSIONS

We conclude that ear malformations are associated with an increased frequency of clinically significant structural renal anomalies compared with the general population. This is due to the observation that auricular malformations often are associated with specific MCA syndromes that have high incidences of renal anomalies. These include CHARGE association, Townes-Brocks syndrome, branchio-oto-renal syndrome, Nager syndrome, Miller syndrome, and diabetic embryopathy. Patients with auricular anomalies should be assessed carefully for accompanying dysmorphic features, including facial asymmetry; colobomas of the lid, iris, and retina; choanal atresia; jaw hypoplasia; branchial cysts or sinuses; cardiac murmurs; distal limb anomalies; and imperforate or anteriorly placed anus. If any of these features are present, then a renal ultrasound is useful not only in discovering renal anomalies but also in the diagnosis and management of MCA syndromes themselves. A renal ultrasound should be performed in patients with isolated preauricular pits, cup ears, or any other ear anomaly accompanied by 1 or more of the following: other malformations or dysmorphic features, a family history of deafness, auricular and/or renal malformations, or a maternal history of gestational diabetes. In the absence of these findings, renal ultrasonography is not indicated.