Plant growth limitation and nutrient loss following piled burning in slash and burn agriculture

In the forest zone of Cameroon, small-scale family farmers practicing traditional slash and burn practices achieve a clear field by piled burning of the branches and trunks of cleared vegetation. Plant growth inhibition on ash patches, and the risk of nutrient loss from these areas, was evaluated on field plots on which 0.5 t m(-2) or 1.0 t m(-2) of wood was piled and burnt, and in laboratory studies. The ash produced by burning was strongly alkaline, and laboratory bio-assessment studies showed that the saline, high pH conditions produced in ash patches prevented germination and plant growth for up to two wet seasons, as is observed in the field. Field and laboratory studies demonstrated rapid release (1 wet season) of K and S from the ash and the loss of a substantial portion of these nutrients from the soil profile by leaching. In contrast, leaching carries Mg from the ash gradually (3 to 4 wet seasons), while Ca, Cu, Zn and P are leached slowly. The nutrients contained in ash patches are considered at risk of loss both through leaching (K and S) and by erosion of ash (Ca, Mg, Cu, Zn and P). Farmers should be encouraged to spread ash patches prior to cultivation in order to exploit the nutrient content of ash and to lessen the risk of nutrient loss.

Biodiversity: bridging the gap between condition and conservation

The aim of this study is to create a two-tiered assessment combining restoration and conservation, both needed for biodiversity management. The first tier of this approach assesses the condition of a site using a standard bioassessment method, AUSRIVAS, to determine whether significant loss of biodiversity has occurred because of human activity. The second tier assesses the conservation value of sites that were determined to be unimpacted in the first step against a reference database. This ensures maximum complementarity without having to set a priori target areas. Using the reference database, we assign site-specific and comparable coefficients for both restoration (Observed/Expected taxa with > 50% probability of occurrence) and conservation values (O/E taxa with < 50%, rare taxa). In a trial on 75 sites on rivers around Sydney, NSW, Australia we were able to identify three regions: (1) an area that may need restoration; (2) an area that had a high conservation value and; (3) a region that was identified as having significant biodiversity loss but with high potential to respond to rehabilitation and become a biodiversity hotspot. These examples highlight the use of the new framework as a comprehensive system for biodiversity assessment.

Equine laminitis: loss of hemidesmosomes in hoof secondary epidermal lamellae correlates to dose in an oligofructose induction model: an ultrastructural study

Reasons for performing study: Light microscopical studies show that the key lesion of laminitis is separation at the hoof lamellar dermal-epidermal interface. More precise knowledge of the damage occurring in the lamellar basement membrane zone may result if laminitis affected tissue is examined with the transmission electron microscope. This could lead to better understanding of the pathogenesis of lesions and the means of treatment or prevention. Objectives: To investigate the ultrastructure of acute laminitis as disease of greater severity is induced by increasing oligofructose (OF) dosage. Methods: Three pairs of normal horses, dosed with OF at 7.5, 10 and 12.5 g/kg bwt via nasogastric intubation, developed laminitis 48 h later. Following euthanasia, their forefeet were processed for transmission electron microscopy. Lamellar basal cell hemidesmosome (HD) numbers and the distance between the basal cell plasmalemma and the lamina densa of the basement membrane were estimated and compared to control tissue. Results: Increasing OF dosage caused greater HD loss and more severe laminitis. The characteristic separation of the basement membrane, cytoskeleton failure and rounded basal cell nuclei results from combined HD dysassembly and anchoring filament failure. Conclusions: Without properly assembled HDs, dysadhesion between the lamina densa of the basement membrane (BM) and epidermal basal cells occurs, emphasising the fundamental importance of HDs in maintaining attachment at the lamellar interface. Medical conditions that trigger lamellar matrix metalloproteinase (MMP) activation and/or compromise entry of glucose into lamellar basal cells appear to promote loss and failure of HDs and, therefore, laminitis development. Potential relevance: A correlation between lameness severity and escalating loss of lamellar HDs now exists. Therapy aimed at protecting the lamellar environment from haematogenous delivery of MMP activators or from glucose deprivation may control laminitis development.

PETAL LOSS, a trihelix transcription factor gene, regulates perianth architecture in the Arabidopsis flower

Perianth development is specifically disrupted in mutants of the PETAL LOSS (PTL) gene, particularly petal initiation and orientation. We have cloned PTL and show that it encodes a plant-specific trihelix transcription factor, one of a family previously known only as regulators of light-controlled genes. PTL transcripts were detected in the early-developing flower, in four zones between the initiating sepals and in their developing margins. Strong misexpression of PTL in a range of tissues universally results in inhibition of growth, indicating that its normal role is to suppress growth between initiating sepals, ensuring that they remain separate. Consistent with this, sepals are sometimes fused in ptl single mutants, but much more frequently in double mutants with either of the organ boundary genes cup-shaped cotyledon1 or 2. Expression of PTL within the newly arising sepals is apparently prevented by the PINOID auxin-response gene. Surprisingly, PTL expression could not be detected in petals during the early stages of their development, so petal defects associated with PTL loss of function may be indirect, perhaps involving disruption to signalling processes caused by overgrowth in the region. PTL-driven reporter gene expression was also detected at later stages in the margins of expanding sepals, petals and stamens, and in the leaf margins; thus, PTL may redundantly dampen lateral outgrowth of these organs, helping define their final shape.

On the loss of regularity for a class of weakly hyperbolic operators

In this paper we determine bounds for the optimal loss of regularity in the Sobolev scale for a class of weakly hyperbolic operators. (C) 2009 Elsevier Inc. All rights reserved.

Loss of Ergodicity in the Transition from Annealed to Quenched Disorder in a Finite Kinetic Ising Model

We consider a kinetic Ising model which represents a generic agent-based model for various types of socio-economic systems. We study the case of a finite (and not necessarily large) number of agents N as well as the asymptotic case when the number of agents tends to infinity. The main ingredient are individual decision thresholds which are either fixed over time (corresponding to quenched disorder in the Ising model, leading to nonlinear deterministic dynamics which are generically non-ergodic) or which may change randomly over time (corresponding to annealed disorder, leading to ergodic dynamics). We address the question how increasing the strength of annealed disorder relative to quenched disorder drives the system from non-ergodic behavior to ergodicity. Mathematically rigorous analysis provides an explicit and detailed picture for arbitrary realizations of the quenched initial thresholds, revealing an intriguing ""jumpy"" transition from non-ergodicity with many absorbing sets to ergodicity. For large N we find a critical strength of annealed randomness, above which the system becomes asymptotically ergodic. Our theoretical results suggests how to drive a system from an undesired socio-economic equilibrium (e. g. high level of corruption) to a desirable one (low level of corruption).

Weight loss during prolonged lactation in rural Bangladeshi mothers

To determine the duration of lactation which is associated with weight loss in rural Bangladeshi mothers and also to determine the relationship with consumption patterns of principal food items, a cross-sectional study was carried out among 791 lactating rural Bangladeshi mothers aged 18-40 years. Results were compared with 333 non-pregnant and non-lactating mothers of a similar age group. The duration of lactation was up to 60 months. The mean difference in body-weight and body mass index (BMI) of lactating mothers who breastfed their children up to 24 months was significantly lower compared to non-lactating mothers of the same age group, but no differences were observed for those who breastfed beyond 24 months. The frequency of consumption of principal food items was comparable between the non-lactating and the lactating mothers who breastfed beyond 24 months. Results of multiple linear regression analysis showed that body-weight of mothers was negatively correlated with 1-12 month(s) and 13-24 months of lactation after controlling for height, education, and food consumption (slope -1.04, p < 0.05 and slope -1.23, p < 0.05 respectively). Height and consumption of meat and milk were significantly positively correlated with body-weight (slope 0.53, p < 0.001; slope 1.44, p < 0.001; and slope 0.75, p < 0.05 respectively). The study concluded that Bangladeshi women who breastfed up to 24 months were of lower weight than non-lactating mothers, most likely due to the effect of lactation. These mothers were not taking any additional foods during their lactating period. Based on the findings of the study, it is recommended that mothers consume additional energy-rich foods during the first 24 months of lactation to prevent weight loss.

Tooth loss in Brazilian middle-aged adults: multilevel effects

Objective. To examine the link between tooth loss and multilevel factors in a national sample of middle-aged adults in Brazil. Material and methods. Analyses were based on the 2003 cross-sectional national epidemiological survey of the oral health of the Brazilian population, which covered 13 431 individuals (age 35-44 years). Multistage cluster sampling was used. The dependent variable was tooth loss and the independent variables were classified according to the individual or contextual level. A multilevel negative binomial regression model was adopted. Results. The average tooth loss was 14 (standard deviation 9.5) teeth. Half of the individuals had lost 12 teeth. The contextual variables showed independent effects on tooth loss. It was found that having 9 years or more of schooling was associated with protection against tooth loss (means ratio range 0.68-0.76). Not having visited the dentist and not having visited in the last >= 3 years accounted for increases of 33.5% and 21.3%, respectively, in the risk of tooth loss (P < 0.05). The increase in tooth extraction ratio showed a strong contextual effect on increased risk of tooth loss, besides changing the effect of protective variables. Conclusions. Tooth loss in middle-aged adults has important associations with social determinants of health. This study points to the importance of the social context as the main cause of oral health injuries suffered by most middle-aged Brazilian adults.

Effects of Perilipin (PLIN) Gene Variation on Metabolic Syndrome Risk and Weight Loss in Obese Children and Adolescents

Context: Genetic polymorphisms at the perilipin (PLIN) locus have been investigated for their potential utility as markers for obesity and metabolic syndrome (MS). We examined in obese children and adolescents (OCA) aged 7-14 yr the association of single-nucleotide polymorphisms (SNP) at the PLIN locus with anthropometric, metabolic traits, and weight loss after 20-wk multi-disciplinary behavioral and nutritional treatment without medication. Design: A total of 234 OCA [body mass index (BMI = 30.4 +/- 4.4 kg/m(2); BMI Z-score = 2.31 +/- 0.4) were evaluated at baseline and after intervention. We genotyped four SNPs (PLIN1 6209T -> C, PLIN4 11482G -> A, PLIN5 13041A -> G, and PLIN6 14995A -> T). Results: Allele frequencies were similar to other populations, PLIN1 and PLIN4 were in linkage disequilibrium (D` = 0.999; P < 0.001). At baseline, no anthropometric differences were observed, but minor allele A at PLIN4 was associated with higher triglycerides (111 +/- 49 vs. 94 +/- 42 mg/dl; P = 0.003), lower high-density lipoprotein cholesterol (40 +/- 9 vs. 44 +/- 10 mg/dl; P = 0.003) and higher homeostasis model assessment for insulin resistance (4.0 +/- 2.3 vs. 3.5 +/- 2.1; P +/- 0.015). Minor allele A at PLIN4 was associated with MS risk (age and sex adjusted) hazard ratio 2.4 (95% confidence interval = 1.1-4.9) for genotype GA and 3.5 (95% confidence interval = 1.2-9.9) for AA. After intervention, subjects carrying minor allele T at PLIN6 had increased weight loss (3.3 +/- 3.7 vs. 1.9 +/- 3.4 kg; P = 0.002) and increased loss of the BMI Z-score (0.23 +/- 0.18 vs. 0.18 +/- 0.15; P +/- 0.003). Due to group size, risk of by-chance findings cannot be excluded. Conclusion: The minor A allele at PLIN4 was associated with higher risk of MS at baseline, whereas the PLIN6 SNP was associated with better weight loss, suggesting that these polymorphisms may predict outcome strategies based on multidisciplinary treatment for OCA. (J Clin Endocrinol Metab 93: 4933-4940, 2008)

Intimal dissection of the hepatic artery after thrombectomy as a cause of graft loss in pediatric living-related liver transplantation

HAT is the main cause of graft loss in pediatric living-related LTx. Revascularization of the graft by thrombectomy and re-anastomosis has been reported to be effective for graft salvage in cases of HAT and should be attempted when potential donors are not available for emergency re-transplantation. Immediate complications secondary to revascularization attempts in cases of HAT are not described. Late complications are mainly related to biliary tree ischemia. We report a case of child who experienced intimal hepatic artery dissection, which extended into intra-hepatic branches of the artery after a thrombectomy with a Fogarty balloon catheter in an attempt to restore arterial flow after HAT. This complication led to acute deterioration of the graft and the need for emergency re-transplantation.

The effect of oestrogen and alendronate therapies on postmenopausal bone loss around osseointegrated titanium implants

Objectives This study evaluated the influence of oestrogen deficiency and its therapies on bone tissue around osseointegrated implants. Methods Implants were placed in 66 female rats tibiae. The animals were assigned into five groups: control (CTL), sham, ovariectomy (OVX), oestrogen (EST), and alendronate (ALE). While CTL was sacrificed 60 days after implant placement, other groups were subjected to ovariectomy or sham surgery according to group and euthanized after 90 days. Blood and urine samples were collected at sacrifice day for osteocalcin (OCN) and deoxypyridinoline (DPD) quantification. Densitometry of femur and lumbar vertebrae was performed in order to evaluate rats` skeletal impairment. Non-decalcified sections were referred to fluorescent and light microscopy for analyses of mineral apposition rate (MAR), eroded and osteoclastic surfaces, bone-to-implant contact (BIC), and bone area fraction occupancy (BAFO). Results Results from the OVX group showed significantly lower bone mineral density (BMD), BIC, BAFO, and MAR, while OCN, deoxipiridinoline, eroded surface and ostecoclastic surface were increased compared with the other groups of the study. ALE reduced OCN and DPD concentrations, MAR, osteoclastic and eroded surfaces, and no difference was in BIC and BAFO relative to SHAM. EST and CTL showed similar results to SHAM for measurements. Conclusions Oestrogen deficiency exerted a negative influence on bone tissue around implants, while oestrogen replacement therapy and alendronate were effective against its effects. Although alendronate therapy maintained the quantity of bone around implants, studies evaluating bone turnover kinetics are warranted. To cite this article:Giro G, Coelho PG, Pereira RMR, Jorgetti V, Marcantonio E Jr, Orrico SRP. The effect of oestrogen and alendronate therapies on postmenopausal bone loss around osseointegrated titanium implants.Clin. Oral Impl. Res. 22, 2011; 259-264.doi: 10.1111/j.1600-0501.2010.01989.x.

Insertion/deletion polymorphism of the angiotensin converting enzyme gene and loss of the insertion allele in aldosterone-producing adenoma

The genetic mechanisms responsible for the formation of adrenocortical adenomas which autonomously produce aldosterone are largely unknown, The adrenal renin-angiotensin system has been implicated in the pathophysiology of these tumours, Angiotensin-converting enzyme (ACE) catalyses the generation of angiotensin II, and the insertion/deletion (I/D) polymorphism of the ACE gene regulates up to 50% of plasma and cellular ACE variability in humans. We therefore examined the genotypic and allelic frequency distributions of the ACE gene I/D polymorphism in 55 patients with aldosterone-producing adenoma, APA, (angiotensin-unresponsive APA n = 28, angiotensin-responsive APA n = 27), and 80 control subjects with no family history of hypertension, We also compared the ACE gene I/D polymorphism allelic pattern in matched tumour and peripheral blood DNA in the 55 patients with APA, The frequency of the D allele was 0.518 and 0.512 and the I allele was 0.482 and 0.488 in the APA and control subjects respectively, Genotypic and allelic frequency analysis found no significant differences between the groups, Examination of the matched tumour and peripheral blood DNA samples revealed the loss of the insertion allele in four of the 25 patients who were heterozygous for the ACE I/D genotype. The I/D polymorphism of the ACE gene does not appear to contribute to the biochemical and phenotypic characteristics of APA, however, the deletion of the insertion allele of the ACE gene I/D polymorphism in 16% of aldosterone-producing adenomas may represent the loss of a tumour suppressor gene/s or other genes on chromosome 17q which may contribute to tumorigenesis in APA.

Loss of heterozygosity of the APC gene in oral squamous cell carcinoma

The aim of this study was to investigate loss of heterozygosity (LOH) of the APC tumor suppressor gene loci, using restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) in 40 cases of oral squamous cell carcinoma (OSCC). Observed informativity was 72.5% for APC exon 11 and 82.5% for APC exon 15. LOH at APC exon 11 was observed in 2 (6.9%) of 29 informative cases, and no LOH was observed for APC exon 15. Our results suggest that inactivation of the APC gene plays a minor role in the carcinogenesis of OSCC. (C) 2008 Elsevier GmbH. All rights reserved.

Mammaplasty with Inferior Pedicle Flap After Massive Weight Loss

After massive weight loss, one of the stigmas that afflict women is the remaining deformity of the breasts which become flaccid and ptotic, with an absent or flat upper pole. The authors propose the use of a well-established mammaplasty technique to fill the upper pole, reshape the breast cone, and correct ptosis with nipple-areola complex (NAC) repositioning. A total of 16 patients were analyzed; all underwent gastroplasty between 18 and 24 months prior to mammaplasty. The mean age was 41.6 years (range = 26-62) and the mean BMI previous to the mammaplasty was 29.2 kg/m(2) (range = 24.9-38.9). The technique included a dermo-lipo glandular flap pedicled on the inframammary fold (IMF) together with a superior flap containing the NAC. All patients who underwent surgery were satisfied with the outcomes since a more aesthetic breast shape was achieved, with projection of the upper pole and correction of ptosis. Adverse events included dehiscence at the junction point of the flaps in the inframammary fold, which resolved with secondary-intention wound healing in three patients; partial necrosis of the areola in one patient; epidermolysis in one of the NACs in one patient; and infection in one of the breasts in one patient, which resolved with proper antibiotic therapy. When compared to the current mammaplasty techniques performed in formerly obese patients, this is a good surgical option because it uses tissues adjacent to the breast itself and does not require silicone prosthesis for breast augmentation. The patients reported increased self-esteem and improvement in their quality of life.

Collagen and Elastic Content of Abdominal Skin After Surgical Weight Loss

Collapsed skin folds after bariatric weight loss are often managed by plastic procedures, but changes in dermal composition and architecture have rarely been documented. Given the potential consequences on surgical outcome, a prospective histochemical study was designed. The hypothesis was that a deranged dermal fiber pattern would accompany major changes in adipose tissue. Female surgical candidates undergoing postbariatric abdominoplasty (n = 40) and never obese women submitted to control procedures (n = 40) were submitted to double abdominal biopsy, respectively in the epigastrium and hypogastrium. Histomorphometric assessment of collagen and elastic fibers was executed by the Image Analyzer System (Kontron Electronic 300, Zeiss, Germany). Depletion of collagen, but not of elastic fibers, in cases with massive weight loss was confirmed. Changes were somewhat more severe in epigastrium (P = 0.001) than hypogastrium (P = 0.007). Correlation with age did not occur. (1) Patients displayed lax, soft skin lacking sufficient collagen fiber network. (2) Elastic fiber content was not damaged, and was even moderately increased in epigastrium; (3) Preoperative obesity negatively correlated with hypogastric collagen concentration; (4) Future studies should pinpoint the roles of obesity, and especially of massive weight loss, on dermal architecture and response to surgery.