Methane emissions from beef cattle grazing on semi-natural upland and improved lowland grasslands.

In ruminants, methane (CH4) is a by-product of digestion and contributes significantly to the greenhouse gas emissions attributed to agriculture. Grazed grass is a relatively cheap and nutritious feed but herbage species and nutritional quality vary between pastures, with management, land type and season all potentially impacting on animal performance and CH4 production. The objective of this study was to evaluate performance and compare CH4 emissions from cattle of dairy and beef origin grazing two grassland ecosystems: lowland improved grassland (LG) and upland semi-natural grassland (UG). Forty-eight spring-born beef cattle (24 Holstein-Friesian steers, 14 Charolais crossbred steers and 10 Charolais crossbred heifers of 407 (s.d. 29), 469 (s.d. 36) and 422 (s.d. 50) kg BW, respectively), were distributed across two balanced groups that grazed the UG and LG sites from 1 June to 29 September at stocking rates (number of animals per hectare) of 1.4 and 6.7, respectively. Methane emissions and feed dry matter (DM) intake were estimated by the SF6 tracer and n-alkane techniques, respectively, and BW was recorded across three experimental periods that reflected the progression of the grazing season. Overall, cattle grazed on UG had significantly lower (P<0.001) mean daily DM intake (8.68 v. 9.55 kg/day), CH4 emissions (176 v. 202 g/day) and BW gain (BWG; 0.73 v. 1.08 kg/day) than the cattle grazed on LG but there was no difference (P>0.05) in CH4 emissions per unit of feed intake when expressed either on a DM basis (20.7 and 21.6 g CH4 per kg DM intake for UG and LG, respectively) or as a percentage of the gross energy intake (6.0% v. 6.5% for UG and LG, respectively). However, cattle grazing UG had significantly (P<0.001) greater mean daily CH4 emissions than those grazing LG when expressed relative to BWG (261 v. 197 g CH4/kg, respectively). The greater DM intake and BWG of cattle grazing LG than UG reflected the poorer nutritive value of the UG grassland. Although absolute rates of CH4 emissions (g/day) were lower from cattle grazing UG than LG, cattle grazing UG would be expected to take longer to reach an acceptable finishing weight, thereby potentially off-setting this apparent advantage. Methane emissions constitute an adverse environmental impact of grazing by cattle but the contribution of cattle to ecosystem management (i.e. promoting biodiversity) should also be considered when evaluating the usefulness of different breeds for grazing semi-natural or unimproved grassland.

Visual and anatomical outcomes following vitrectomy for complications of diabetic retinopathy: the DRIVE UK study.

INTRODUCTION: End-stage diabetic eye disease is an important cause of severe visual impairment in the working-age group. With the increasing availability of refined surgical techniques as well as the early diagnosis of disease because of screening, one would predict that the prevalence of this condition is decreasing and the visual outcome is improving. AIM: To study the prevalence and visual outcome following vitrectomy for complications of diabetic retinopathy. MATERIALS AND METHODS: This study identified the patients who underwent vitrectomy from January 2007 to December 2009 because of diabetes-related complications in South East London. Data collected included baseline demographics, best-corrected visual acuity, indication for the vitrectomy, complication, outcome, and duration of follow-up. RESULTS: The prevalence of people requiring vitrectomy who are registered in the diabetes register of this region was 2 per 1000 people with diabetes. Vitrectomy was required in 185 eyes of 158 patients during this period. These included 83 Caucasians, 51 Afro-Caribbeans, 17 South Asians, and 7 from other ethnic groups. There were 58 patients with type I diabetes and 100 with type II, with a mean duration of diabetes of 23 and 16.5 years, respectively. The reason for vitrectomy included tractional retinal detachment (TRD) in 109 eyes, non-clearing vitreous haemorrhage (NCVH) in 68 eyes, and other causes in 8 eyes. In all, 50% of the eyes with TRD and NCVH, and 87% of the eyes with NCVH improved by at least three ETDRS lines at 12 months. Poor predictors of visual success included longer duration of diabetes (OR: 0.69), use of insulin (OR: 0.04), presence of ischaemic heart disease (OR: 0.04), delay in surgery (OR: 0.59), and the failure to attend clinic appointments (OR: 0.58). Preoperative use of intravitreal bevacizumab in eyes with TRD undergoing vitrectomy showed a marginal beneficial effect on co-existent maculopathy (P=0.08) and required less laser intervention post procedure, but did not affect the number of episodes of late-onset vitreous haemorrhage post vitrectomy (P=0.81). CONCLUSION: Visual outcome has improved significantly in eyes with complications due to diabetic retinopathy compared with the previously reported Diabetic Vitrectomy Study.

Interrelation of parathyroid hormone and vitamin D metabolites in adolescents from the UK and The Gambia.

Parathyroid hormone (PTH) is used as a marker of vitamin D (VD) status. However, PTH depends on many other factors. The 24,25-dihydroxy VD (24,25VD) concentration may be a sensitive marker because its production is reduced in VD deficiency. The relationship between VD metabolites, their ratio and PTH was investigated in adolescents from the UK and The Gambia with different calcium intakes and VD status. In the UK, there was a significant positive (+ve) association between 25VD and both 1,25-dihydroxy VD (1,25VD) and 24,25VD and a negative (-ve) association with PTH. The 24,25:25VD ratio was consistent across the 25VD concentration range. There was a +ve association between PTH and 1,25:25VD, (1,25+24,25):25VD or 1,25:24,25VD, a -ve association with 24,25VD and none with 1,25VD or 24,25:25VD. Using LnPTH and 1,25:25VD ratio (but not 1,25VD:24,25VD or 25VD:24,25VD) increased uniformity between groups and strength of relationships compared to PTH and 1,25 or 25VD alone. In The Gambia, there was a significant -ve relationship between 25VD and PTH and none with 1,25VD. There was a +ve association between 1,25VD or 1,25:25VD and PTH. The more uniform prediction of PTH by the 1,25VD:25VD ratio may be because this better reflects the extent to which PTH-induced 1,25VD production can be met by VD supply. Further validation is needed.

Older people in China and the United Kingdom differ in the relationships among parathyroid hormone, vitamin D, and bone mineral status.

To explore whether there are ethnic differences in relationships among parathyroid hormone (PTH), vitamin D, and bone mineral status, 352 healthy volunteers, 60-83 years old, were studied in Shenyang, Peoples' Republic of China (108 men, 110 women), and in Cambridge, UK (67 men, 67 women), in late winter. Early morning fasting blood and 2-h fasting urine were analyzed for 25-hydroxyvitamin D (25OH-D), PTH, and free deoxypyridinoline (DPD). Hip bone mineral status was measured using dual-energy X-ray absorptiometry (Lunar). There were significant differences (P < 0.001) in plasma 25OH-D and PTH concentrations between Shenyang and Cambridge [25OH-D nmol/L: Shenyang = 29.0 (SD 12.7), Cambridge = 35.7 (12.9)]; PTH ng/L: Shenyang = 34.3 (13.4), Cambridge = 25.2 (11.0)]. PTH was negatively related to 25OH-D in both populations. The relationship was exponential, best described by an inverse log-log equation with no break point (P < 0.001), indicating that the exponential curve did not tend toward a low plateau. PTH was higher for a given 25OH-D and decreased less with increasing 25OH-D in Shenyang than in Cambridge (country-ln25OH-D interaction, P = 0.0005). After adjusting for bone area, weight, height, age, and sex, hip bone mineral content (BMC) was significantly related to PTH concentration in Cambridge but not in Shenyang [femoral neck coefficient: Cambridge = -0.064 (SE 0.027), P = 0.02; Shenyang = -0.027 (0.028), P = 0.3; trochanter: Cambridge = -0.116 (0.034), P = 0.001; Shenyang = -0.019 (0.027), P = 0.5]. There was a significant country-lnPTH interaction at the trochanter (P = 0.02), but not at the femoral neck (P = 0.7). A weak positive association between BMC at the femoral neck and 25OH-D concentration was found in Cambridge [coefficient: 0.054 (0.028), P = 0.05] but not in Shenyang (coefficient: -0.013, P = 0.5; country-ln25OH-D interaction, P = 0.07). Urinary DPD concentration was also positively related to plasma PTH concentration in Cambridge subjects only [coefficient: 0.2 (0.08), P = 0.02]. These data suggest that although PTH increases when 25OH-D decreases, and Chinese people have a higher PTH for a given 25OH-D, older Chinese adults may be more resistant than Britons to the effects of PTH on bone.

Age- and gender-related differences in bone mineral status and biochemical markers of bone metabolism in Northern Chinese men and women.

The aim of this study was to provide insight into the bone mineral status and biochemical markers of bone metabolism in a Chinese population from Shenyang, in the north of China, where hip fracture incidence is low. A total of 194 healthy men and women, aged 25-35 years and 65-75 years, were studied. Bone mineral density (BMD) at the lumbar spine (LS) and femoral neck (FN) was measured using dual-energy X-ray absorptiometry. Fasting blood and 24 h urine samples were collected for bone alkaline phosphatase (bAP), osteocalcin, calcium, phosphate, and free deoxypyridinoline (Dpd). Both older women and men had lower BMD compared with younger women and men by 27.2 +/- 3.0% (mean +/- SE) and 9.8 +/- 3.0% at the LS and 22.0 +/- 3.4% and 12.8 +/- 3.4% at the FN, respectively, after adjusting for bone and body size (p < 0.01). BMD at the two sites was lower in older women than in older men by 10.7 +/- 4.1% and 10.2 +/- 4.2%, respectively, after size correction (p < 0.05). Plasma bAP, osteocalcin, calcium, and phosphate concentrations were higher in older women than younger women by 69.3 +/- 9.7%, 77.2 +/- 11.1%, 7.5 +/- 2.3%, and 8.0 +/- 3.8%, respectively, and older men by 67.6 +/- 11.1%, 72.1 +/- 11.0%, 7.7 +/- 2.3%, and 23.8 +/- 3.8%, respectively (p < 0.01). However, plasma osteocalcin, calcium, and phosphate concentrations were lower in older men compared with their younger counterparts by 35.6 +/- 11.0%, 8.7 +/- 2.3%, and 14.1 +/- 3.8%, respectively (p < 0.05). Urinary calcium and phosphate output were lower in older men compared with younger men by 48.0 plus minus 10.3% and 27.6 +/- 6.9%, respectively (p < 0.01), whereas there were no differences between older and younger women. No differences in Dpd between older and younger groups were found. This study demonstrates that bone mineral status is lower in older people in Shenyang, as has been shown in populations elsewhere. The pronounced low bone mineral status in older women may be associated with increased bone turnover, which was not observed in older men.

Inbred lines of mice derived from long-term growth selected lines: unique resources for mapping growth genes.

Lines of mice selected for many generations for high or low growth in several laboratories around the world have been collected, and from these, inbred lines are being developed by recurrent full-sib mating in Edinburgh. There are seven high selected lines and four low lines (each low line is from the same base population as one of the high lines), and the histories of each are summarized. Mean body weight of males at 70 days of age in the Edinburgh laboratory in the heaviest inbred line (77 g) is 4.8-fold higher than in the lightest line (16 g), and 1.9-fold higher than in the least extreme high line (41 g). Litter size, food intake, and fat content also differ substantially. These inbred extreme selected lines are a uniquely valuable resource for QTL or gene mapping, candidate gene identification, and elucidation of epistatic effects.

Macular hole surgery using silicone oil tamponade.

BACKGROUND/AIMS: Most surgeons performing macular hole surgery using long acting gas recommend strict postoperative face down posturing for 10-15 days. Patients with chronic systemic illness such as arthritis may be unable to carry out this postoperative regime. Thus there is a need for alternative techniques that would eliminate such a regime. The authors review a series of patients who underwent macular hole surgery using silicone oil without any postoperative posturing. METHODS: A retrospective case note review was performed of patients who had undergone macular hole surgery with silicone oil tamponade. The patients were unable to posture due to chronic illness and had stage 2, 3, or 4 full thickness macular holes. Removal of silicone oil performed with or without cataract surgery was arranged 3 months or more after surgery. RESULTS: 10 eyes of 10 patients underwent surgery. Duration of oil tamponade ranged from 3-9 months. Following oil removal the hole was closed in eight eyes (80%), of which only three showed any improvement in visual acuity (38%) even after cataract extraction. All eyes developed cataract to varying degrees and one eye developed raised intraocular pressure which settled after oil removal. A serious complication, endophthalmitis, occurred in one eye following removal of sutures after cataract extraction. CONCLUSION: The anatomical results (80%) in this series are in keeping with those reported in other studies using gas tamponade. The visual results are disappointing and less rewarding than those obtained after successful surgery using gas tamponade.

The role of arbuscular mycorrhizal fungi in the transfer of nutrients between white clover and perennial ryegrass.

A glasshouse experiment was conducted in which 15N was used as a tracer applied as (15NH4)2SO4 to donor plants of white clover and perennial ryegrass. Nitrogen transfer via hyphae of arbuscular mycorrhizal fungi (AMF) or by other routes was studied by separating the root systems of the two plant species, as donors and receivers, when growing in the same pot, with selective mesh barriers of varying pore sizes in the presence and absence of AMF. Inoculation with AMF increased DM production and nitrogen (N) yield of clover plants. Transfer of 15N occurred between white clover and grass plants but was independent of AMF. Pore size of the mesh barriers controlled the degree of 15N enrichment in the grass, suggesting that transfer was mediated by mass flow and/or diffusion. Additional experiments showed that grass roots could pass through pores of 60-microm diameter, and hyphal links could not be detected by autoradiography, thus supporting the conclusions of the tracer experiment.

Uptake of Zn by arbuscular mycorrhizal white clover from Zn-contaminated soil.

A randomised block glasshouse pot experiment compared the growth and Zn uptake of mycorrhizal and nonmycorrhizal white clover plants grown in a sterile soil/sand mixture containing 25 mg Zn kg(-1) to which five application rates of Zn (as ZnSO4) from 0 to 400 mg kg(-1) were made. Two mycorrhizal inocula infected roots from the field and from clover trap cultures, were compared. Mycorrhizal infection (ranging from 33% to 46% of total root length) and Zn application had little effect on plant growth. Increasing Zn application rate led to increased uptake of Zn in roots and shoots (especially roots), but the increases were significantly greater in non-mycorrhizal controls than in mycorrhizal treatments. In contrast, P uptake was higher in mycorrhizal than in non-mycorrhizal plants. Plants that received trap culture inoculum had significantly lower Zn uptake than those that received field inoculum. The results indicate that mycorrhizal infection may have exerted some protective effect against plant Zn accumulation at the range of soil Zn concentrations studied and may have immobilised Zn in or near the roots to some extent. However, this mycorrhizal effect cannot be explained simply by tissue dilution, hyphal sequestration or root immobilisation of Zn.

Choroidal effusions and hypotony caused by severe anterior lens capsule contraction after cataract surgery.

PURPOSE: To report the clinical features and management of two patients with pseudophakic anterior capsule contraction with secondary tractional ciliary body detachments and hypotonous choroidal effusions. METHODS: Case reports. RESULTS: In two eyes of two patients with pseudophakia, severe anterior lens capsule contraction and tractional ciliary body detachments, anterior capsulotomy (one Nd:YAG laser, one surgical), was followed by resolution of the ocular hypotony and resolution/nonrecurrence of the choroidal effusions. In both cases, continuous curvilinear capsulorhexis was used during cataract surgery. CONCLUSION: Anterior capsule contraction following pseudophakia may result in tractional ciliary detachment and secondary ocular hypotony. Radial anterior capsulotomy appeared to be effective in both cases.

Pruritus: more scratch than itch.

Itch is one of the major symptoms of skin disease although it remains poorly studied. Little is known about its mediators or the neurological processes involved in either the detection of an itch stimulus or the induction of the main response to itch, scratch. This lack of knowledge may be due to the subjective nature of the sensation itself and the related difficulties in quantifying it, and is compounded by the absence of a convincing animal model. Defining itch as that sensation which provokes the desire to scratch provides two approaches to measurement, that of itch itself, and the behavioural response, scratch. The measurement of itch itself traditionally involves the use of questionnaires or visual analogue scale, both of which rely on the dubious assumption that the subject is able to relate their experiences accurately. By contrast experimental induction of itch and measurement of areas of allokinesis around application sites may provide a more reliable and repeatable method of itch quantification. Recent advances in two areas that may prove relevant are discussed: new technological improvements in movement meters and compatible software; and some recently described animal models.

Effect of growth hormone on height, weight, and body composition in Prader-Willi syndrome.

AIMS: To evaluate the effect of the administration of growth hormone on stature, body weight, and body composition in children aged between 4 and 10 years with Prader-Willi syndrome. METHODS: Height, weight, and skinfold thickness were recorded in 25 children using standard anthropometric techniques at recruitment, and six months later, shortly before the start of daily subcutaneous injections of growth hormone. Body composition was assessed via a measurement of total body water using stable isotopes. Measurements were repeated at the end of the six months of growth hormone administration. Measurements of height, weight, and skinfold thickness were expressed as standard deviation scores (SDSs). RESULTS: There was a significant reduction in the percentage of body fat after growth hormone treatment; height velocity doubled during treatment; body weight did not change significantly when expressed as an SDS. Skinfold thickness at both the triceps and subscapular site decreased in absolute terms and when expressed as an SDS. CONCLUSIONS: These results indicate sufficient potential benefit to justify a more prolonged trial of growth hormone treatment and an exploration of different dosage regimens in children with Prader-Willi syndrome.

Energy intake in early infancy and childhood fatness.

OBJECTIVE: To investigate whether aspects of infant energy intake are related to fatness in early childhood. DESIGN: Longitudinal investigation of infants studied at 12 weeks and 2-3.5 y. SUBJECTS: 20 healthy infants, breast-fed or formula-fed, from the general population. MEASUREMENTS: Milk volume intake (MVI) by deuterium turnover, estimated energy intake, weaning status and body composition in infancy, body composition in childhood. RESULTS: MVI was not related to infant skinfolds or percentage fat. Weaning was inversely related to MVI (P < 0.04) at 12 weeks, and inversely related to skinfolds (P = 0.055) and fat mass (P = 0.020) in childhood. MVI and total energy intake were not related to childhood fatness. CONCLUSIONS: Early weaning was associated with a moderate reduction in childhood fatness. Two possible mechanisms are discussed. However, early infant energy intake was not an important determinant of later fatness in this population.

Telescoping intramedullary rodding with Bailey-Dubow nails for recurrent pathologic fractures in children without osteogenesis imperfecta.

We reviewed four children with multiple, recurrent, pathologic fractures caused by bone disease, excluding osteogenesis imperfecta, and in whom multiple osteotomies with telescoping intramedullary stabilization had been performed. The diagnoses were myelomeningocele in two children and Rett syndrome and fibrous dysplasia in one child each. Five long bones were stabilized; four femora and one tibia. The average age at surgery was 6 years 6 months; the average number of fractures that had occurred in the involved bone before surgery was 3.0 per bone. At an average follow-up of 2 years 4 months, the average number of fractures that had occurred after surgery in the stabilized bones was 0.2 per bone. There were no infections, nonunions, or rod complications. We believe that in the carefully selected patient, multiple osteotomies with intramedullary telescoping rod stabilization can be quite successful in solving the problem of recurrent fractures in children with diseases other than osteogenesis imperfecta.

Investigation of the relationship between infant temperament and later body composition.

OBJECTIVE: To investigate the ability of maternally-rated infant temperament to predict fatness and activity patterns in early childhood. DESIGN: Longitudinal investigation of infants studied at 12 weeks and followed up at 2-3.5 y of age. SUBJECTS: Thirty healthy full-term infants from the general population. MEASUREMENTS: Body composition, behavioural activity and temperament at 12 weeks; anthropometry, body composition, diet and behavioural activity at follow-up. RESULTS: Infant temperament predicted later behaviour and fatness. Easily soothable infants had leaner childhood skinfold thicknesses (P < 0.02) and were more active in childhood (P < 0.025). Infant distress was also related to childhood diet composition. CONCLUSIONS: Infant temperament can predict later body composition and behaviour. Both energy intake and energy expenditure may be mechanisms by which the relationship develops.

Total energy expenditure in 9 month and 12 month infants.

OBJECTIVES: To measure the total energy expenditure of 9 and 12 month old infants and compare with current recommendations for energy intake. DESIGN: Cross-sectional study. Total energy expenditure assessed using the doubly labelled water technique over a 10 d period. Classical anthropometric measurements taken. SETTING: Community based study in and around Cambridge, UK. SUBJECTS: Twenty infants aged 9 months of age and 20 infants aged 12 months of age recruited via local hospital birth records. MAIN OUTCOME MEASURES: Total energy expenditure calculated via the doubly labelled water technique. RESULTS: Measurements of total energy expenditure was successful in 34 cases. Mean total energy expenditure was 73.5 kcal/kg, 73.2 kcal/kg, 77.1 kcal/kg and 77.6 kcal/kg in the nine month old boys, nine month old girls, twelve month old boys and twelve month old girls respectively. These measurements are approximately 17% below current recommendations (FAO/WHO/UNU, 1985) at nine months of age and 22% below at one year of age. CONCLUSION: The data are consistent with findings in younger infants and older children in that the measurements of total energy expenditure are about 20-25% below current recommendations. It is unlikely that contemporary infants are being underfed and thus more likely that changes in feeding practices and modification of infant formula composition has led to the reduction in energy intake and energy expenditure in such infants.

The relationship between components of infant energy expenditure and childhood body fatness.

OBJECTIVE: To investigate whether any component of infant energy expenditure is related to fatness in early childhood, and whether infant fatness is related to childhood variables. DESIGN: Longitudinal investigation of infants studied at 12 weeks and followed up at 2.5 to 3.5 years of age. SUBJECTS: 30 healthy full-term infants selected from the general population. MEASUREMENTS: Sleeping metabolic rate, total energy expenditure, anthropometry and behaviour at 12 weeks; anthropometry, body composition and behaviour in follow-up. RESULTS: Energy expenditure at 12 weeks (minimal metabolism, total energy expenditure, energy expended on physical activity, behaviour) showed no relationship with later fatness. Infant fatness (skinfold thicknesses and percentage fat) showed in contrast a strong relationship with childhood fatness. Infant fatness also predicted childhood behaviour. CONCLUSIONS: These data do not support the theory that reduced energy expenditure in early infancy is related to later fatness. However, infant fatness influences both later fatness and activity patterns.

Good Samaritan surgeon wrongly accused of contributing to President Lincoln's death: an experimental study of the President's fatal wound.

BACKGROUND: When President Abraham Lincoln was shot in the back of the head at Ford's Theater in Washington, D.C., on April 14, 1865, he was immediately rendered unconscious and apneic. Doctor Charles A. Leale, an Army surgeon, who had special training in the care of brain injuries, rushed to Lincoln's assistance. When Doctor Leale probed the wound in Lincoln's thickened scalp, feeling for the bullet, he dislodged a blood clot, and Lincoln began to breathe again. However, Lincoln progressively deteriorated and died at 7:22 AM on April 15, 1865. During the postmortem examination of Lincoln's body, numerous secondary missiles of bone and metal were found in the track of pultaceous brain tissue, extending completely through the brain to the front of the skull. In February 1995, an article in a popular magazine alleged that Doctor Leale had caused further (fatal) damage to Lincoln's brain by thrusting his finger into the brain through the bullet hole. The article alleged (wrongly) that most bullet wounds of the brain incurred in Civil War times were not fatal. STUDY DESIGN: The following study demonstrates that it is impossible to introduce even the tip of the little finger through a hole in the skull resulting from a .41-caliber bullet fired from a derringer. In our study, a .41-caliber derringer was used to fire bullets into numerous fresh skulls; the bullet holes all had razor-sharp edges and were much too small to accommodate a fingertip. RESULTS: Thus, the allegation that President Lincoln's brain was damaged further because Doctor Leale thrust his finger through the bullet hole into the brain parenchyma is not valid. In this study, experimental data are presented to demonstrate the foregoing point. CONCLUSIONS: The wound made by John Wilkes Booth's derringer ball in Lincoln's brain was devastating; it was clearly the cause of his death. Good Samaritan surgeon Leale has been falsely accused of contributing to Lincoln's death.