342 research outputs found
A study of acromegaly-associated headache with somatostatin analgesia.
To characterise somatostatin analogue responsive headache in acromegaly, hitherto not systematically documented in a significant cohort. Using the UK pituitary network, we have clinically characterised a cohort of 18 patients suffering from acromegaly-related headache with a clear response to somatostatin analogues. The majority of patients had chronic migraine (78%) as defined by the International Headache Society diagnostic criteria. Headache was present at the time of acromegaly presentation and clearly associated temporally with disease activity in all cases. Short-acting somatostatin analogues uniquely resolved pain within minutes and the mean duration of analgesia was 1-6 hours. Patients on long-acting analogues required less short-acting injections (mean 3.7 vs. 10.4 injections per day, p=0.005). 94% used somatostatin analogues to control ongoing headache pain. All patients presented with macroadenoma, most had incomplete resection (94%) and headache was ipsilateral to remnant tissue (94%). Although biochemical control was achieved in 78% of patients, headache remained in 71% of them. Patients selected for this study had ongoing headache post-treatment (mean duration 16 years after diagnosis); only 4 patients reached headache remission 26 years (mean, range 14-33) after the diagnosis. Headache in acromegaly patients can be persistent, severe, unrelieved by surgery, long-lasting and uncoupled from biochemical control. We show here that long-acting analogues allow a decrease in the number of short-acting analogue injections for headache relief. Further studies are needed to understand the mechanisms, markers and tumour tissue characteristics of acromegaly-related headache. Until then, this publication serves to provide the clinical characteristics as a reference point for further study
Segment-specific association between cervical pillar hyperplasia (CPH) and degenerative joint disease (DJD)
BACKGROUND: Cervical pillar hyperplasia (CPH) is a recently described phenomenon of unknown etiology and clinical significance. Global assessment of pillar hyperplasia of the cervical spine as a unit has not shown a relationship with degenerative joint disease, but a more sensible explanation of the architectural influence of CPH on cervical spine biomechanics may be segment-specific. OBJECTIVE: The objective of this study was to determine the level of association between degenerative joint disease (DJD) and cervical pillar hyperplasia (CPH) in an age- and gender-matched sample on a [cervical spine] by-level basis. RESEARCH METHODS: Two-hundred and forty radiographs were collected from subjects ranging in age between 40 and 69 years. The two primary outcome measures used in the study were the segmental presence/absence of cervical pillar hyperplasia from C3 to C6, and segment-specific presence/absence of degenerative joint disease from C1 to C7. Contingency Coefficients, at the 5% level of significance, at each level, were used to determine the strength of the association between CPH and DJD. Odds Ratios (OR) with their 95% Confidence Intervals (95% CI) were also calculated at each level to assess the strength of the association. RESULTS: Our study suggests that an approximately two-to-one odds, or a weak-to-moderate correlation, exists at C4 and C5 CPH and adjacent level degenerative disc disease (DDD); with the strongest (overall) associations demonstrated between C4 CPH and C4–5 DDD and between C5 CPH and C5–6 DDD. Age-stratified results demonstrated a similar pattern of association, even reaching the initially hypothesized OR ≥ 5.0 (95% CI > 1.0) or "moderately-strong correlation of C ≥ .4 (p ≤ .05)" in some age categories, including the 40–44, 50–59, and 60–64 years of age subgroups; these ORs were as follows: OR = 5.5 (95% CI 1.39–21.59); OR = 6.7 (95% CI 1.65–27.34); and OR = 5.3 (95% CI 1.35–21.14), respectively. CONCLUSION: Our results suggest that CPH has around two-to-one odds, that is, only a weak-to-moderate association with the presence of DJD (DDD component) at specific cervical spine levels; therefore, CPH may be but one of several factors that contributes (to a clinically important degree) to the development of DJD at specific levels in the cervical spine
Inter-examiner reliability of the diagnosis of cervical pillar hyperplasia (CPH) and the correlation between CPH and spinal degenerative joint disease (DJD)
BACKGROUND: Cervical pillar hyperplasia (CPH) is a recently described phenomenon of unknown aetiology. Its clinical importance is poorly understood at the present time; therefore, the objective of this study was to determine (1) the inter-examiner reliability of detecting CPH and (2) if there is a clinically important correlation (r > 0.4) between the number of cervical spine levels showing signs of degenerative joint disease (DJD) and CPH. METHODS: The sample consisted of 320 radiographs of human male and female subjects who ranged from 40 to 79 years of age. The inter-examiner reliability of assessing the presence/absence of pillar hyperplasia was evaluated on 50 neutral lateral radiographs by two examiners using line drawings and it was quantified using the kappa coefficient of concordance. To determine the presence/absence of hyperplastic pillars as well as the presence/absence of DJD at each intervertebral disc and zygapophysial joint, 320 AP open mouth, AP lower cervical and neutral lateral radiographs were then examined. The unpaired t-test at the 5% level of significance was performed to test for a statistically significant difference between the number of levels affected by DJD in patients with and without hyperplasia. The Spearman's rho at the 5% level of significance was performed to quantify the correlation between DJD and age. RESULTS: The inter-examiner reliability of detecting cervical pillar hyperplasia was moderate with a kappa coefficient of 0.51. The unpaired t-test indicated that there was no statistically significant difference (p > 0.05) between the presence/absence of cervical pillar hyperplasia and the number of levels affected by DJD in an age-matched population, regardless of whether all elements were considered together, or the discs and facets were analyzed separately. A Spearman correlation rank of 0.67 (p < 0.05) suggested a moderately strong correlation between the number of elements (i.e. discs/facets) affected, and the age of the individual. CONCLUSION: Cervical pillar hyperplasia is a reasonable concept that requires further research. Its evaluation is easy to learn and acceptably reliable. Previous research has suggested that CPH may affect the cervical lordosis, and therefore, alter biomechanics which may result in premature DJD. This current study, however, indicates that, globally, CPH does not appear to be related to the development of DJD
Studies on an alkali-thermostable xylanase from Aspergillus fumigatus MA28
An alkalitolerant fungus, Aspergillus fumigatus strain MA28 produced significant amounts of cellulase-free xylanase when grown on a variety of agro-wastes. Wheat bran as the sole carbon source supported higher xylanase production (8,450 U/L) than xylan (7,500 U/L). Soybean meal was observed to be the best nitrogen source for xylanase production (9,000 U/L). Optimum medium pH for xylanase production was 8 (9,800 U/L), though, significant quantities of the enzyme was also produced at pH 7 (8,500 U/L), 9 (8,200 U/L) and 10 (4,600 U/L). The xylanase was purified by ammonium sulphate precipitation and carboxymethyl cellulose chromatography, and was found to have a molecular weight of 14.4 kDa with a Vmax of 980 μmol/min/mg of protein and a Km of approximately 4.9 mg/mL. The optimum temperature and pH for enzyme activity was 50 °C and pH 8, respectively. However, the enzyme also showed substantial residual activity at 60–70 °C (53–75%) and at alkaline pH 8–9 (56–88%)
A Gene's Ability to Buffer Variation Is Predicted by Its Fitness Contribution and Genetic Interactions
BACKGROUND: Many single-gene knockouts result in increased phenotypic (e.g., morphological) variability among the mutant's offspring. This has been interpreted as an intrinsic ability of genes to buffer genetic and environmental variation. A phenotypic capacitor is a gene that appears to mask phenotypic variation: when knocked out, the offspring shows more variability than the wild type. Theory predicts that this phenotypic potential should be correlated with a gene's knockout fitness and its number of negative genetic interactions. Based on experimentally measured phenotypic capacity, it was suggested that knockout fitness was unimportant, but that phenotypic capacitors tend to be hubs in genetic and physical interaction networks. METHODOLOGY/PRINCIPAL FINDINGS: We re-analyse the available experimental data in a combined model, which includes knockout fitness and network parameters as well as expression level and protein length as predictors of phenotypic potential. Contrary to previous conclusions, we find that the strongest predictor is in fact haploid knockout fitness (responsible for 9% of the variation in phenotypic potential), with an additional contribution from the genetic interaction network (5%); once these two factors are taken into account, protein-protein interactions do not make any additional contribution to the variation in phenotypic potential. CONCLUSIONS/SIGNIFICANCE: We conclude that phenotypic potential is not a mysterious "emergent" property of cellular networks. Instead, it is very simply determined by the overall fitness reduction of the organism (which in its compromised state can no longer compensate for multiple factors that contribute to phenotypic variation), and by the number (and presumably nature) of genetic interactions of the knocked-out gene. In this light, Hsp90, the prototypical phenotypic capacitor, may not be representative: typical phenotypic capacitors are not direct "buffers" of variation, but are simply genes encoding central cellular functions
FEM Simulation of Non-Progressive Growth from Asymmetric Loading and Vicious Cycle Theory: Scoliosis Study Proof of Concept
Scoliosis affects about 1-3% of the adolescent population, with 80% of cases being idiopathic. There is currently a lack of understanding regarding the biomechanics of scoliosis, current treatment methods can be further improved with a greater understanding of scoliosis growth patterns. The objective of this study is to develop a finite element model that can respond to loads in a similar fashion as current spine biomechanics models and apply it to scoliosis growth. Using CT images of a non-scoliotic individual, a finite element model of the L3-L4 vertebra was created. By applying asymmetric loading in accordance to the ‘vicious cycle’ theory and through the use of a growth modulation equation it is possible to determine the amount of growth each region of the vertebra will undergo; therefore predict scoliosis growth over a period of time. This study seeks to demonstrate how improved anatomy can expand researchers current knowledge of scoliosis
The effect of growth on the correlation between the spinal and rib cage deformity: implications on idiopathic scoliosis pathogenesis
<p>Abstract</p> <p>Background</p> <p>Numerous studies have attempted to quantify the correlation between the surface deformity and the Cobb angle without considering growth as an important factor that may influence this correlation. In our series, we noticed that in some younger referred children from the school-screening program there is a discrepancy between the thoracic scoliometer readings and the morphology of their spine. Namely there is a rib hump but no spinal curve and consequently no Cobb angle reading in radiographs, discrepancy which fades away in older children. Based on this observation, we hypothesized that in scoliotics the correlation between the rib cage deformity and this of the spine is weak in younger children and vice versa.</p> <p>Methods</p> <p>Eighty three girls referred on the basis of their hump reading on the scoliometer, with a mean age of 13.4 years old (range 7–18), were included in the study. The spinal deformity was assessed by measuring the thoracic Cobb angle from the postero-anterior spinal radiographs. The rib cage deformity was quantified by measuring the rib-index at the apex of the thoracic curve from the lateral spinal radiographs. The rib-index is defined as the ratio between the distance of the posterior margin of the vertebral body and the most extended point of the most projecting rib contour, divided by the distance between the posterior margin of the same vertebral body and the most protruding point of the least projecting rib contour. Statistical analysis included linear regression models with and without the effect of the variable age. We divided our sample in two subgroups, namely the younger (7–13 years old) and the older (14–18 years old) than the mean age participants. A univariate linear regression analysis was performed for each age group in order to assess the effect of age on Cobb angle and rib index correlation.</p> <p>Results</p> <p>Twenty five per cent of patients with an ATI more than or equal 7 degrees had a spinal curve under 10 degrees or had a straight spine. Linear regressions between the dependent variable "Thoracic Cobb angle" with the independent variable "rib-index" without the effect of the variable "age" is not statistical significant. After sample split, the linear relationship is statistically significant in the age group 14–18 years old (p < 0.03).</p> <p>Conclusion</p> <p>Growth has a significant effect in the correlation between the thoracic and the spinal deformity in girls with idiopathic scoliosis. Therefore it should be taken into consideration when trying to assess the spinal deformity from surface measurements. The findings of the present study implicate the role of the thorax, as it shows that the rib cage deformity precedes the spinal deformity in the pathogenesis of idiopathic scoliosis.</p
Evaluation of behavioural and antioxidant activity of Cytisus scoparius Link in rats exposed to chronic unpredictable mild stress
<p>Abstract</p> <p>Background</p> <p>Various human diseases have oxidative stress as one of their component. Many herbs have been reported to exhibit properties that combat oxidative stress through their active constituents such as flavonoids, tannins, phenolic compounds etc. <it>Cytisus scoparius </it>(CS) Link, (Family: Leguminosae), also called <it>Sarothamnus scoparius</it>, has been shown in <it>invitro </it>experiments to be endowed with anti-diabetic, hypnotic and sedative and antioxidant activity. Therefore this study was carried out to evaluate CS for its anxiolytic, antidepressant and anti-oxidant activity in stressed rats.</p> <p>Methods</p> <p>60% methanolic extract of CS was quantified for phenolic content by Folin-Ciocalteau's method. Chronic unpredictable mild stress (CMS) was employed to induce stress in rats. CS (125 and 250 mg/kg, p.o) and diazepam (DZM) (2 mg/kg, p.o) was administered during the 21 day stress exposure period. Anxiolytic and antidepressant activities of CS were assessed in open field exploratory and behavioural despair paradigms, respectively. Plasma glucose and total lipids; endogenous antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT); non-enzymic-ascorbic acid and thiobarbituric acid reactive substances (TBARS) levels were measured in brain, kidneys and adrenals using standard protocols to assess the effect of CS.</p> <p>Results</p> <p>Total phenolic content of CS was found to be 8.54 ± 0.16% w/w. CMS produced anxiogenic and depressive behaviour in experimental rats with metabolic disturbance. Significant decrease in SOD, CAT levels and increase in lipid peroxidation level was observed in stressed rats. CS administration for 21 days during stress exposure significantly increased the ambulatory behaviour and decreased the freezing time in open field behaviour. In behavioural despair test no significant alteration in the immobility period was observed. CS also improved SOD, CAT, and ascorbic acid level and controlled the lipid peroxidation in different tissues.</p> <p>Conclusion</p> <p>CS possesses anti-stress and moderate anxiolytic activity which may be due, in part, to its antioxidant effect that might warrant further studies.</p
Selection of Conditions for Cellulase and Xylanase Extraction from Switchgrass Colonized by Acidothermus cellulolyticus
Solid-state fermentation has been widely used for enzyme production. However, secreted enzymes often bind to the solid substrate preventing their detection and recovery. A series of screening studies was performed to examine the role of extraction buffer composition including NaCl, ethylene glycol, sodium acetate buffer, and Tween 80, on xylanase and cellulase recovery from switchgrass. Our results indicated that the selection of an extraction buffer is highly dependent on the nature and source of the enzyme being extracted. While a buffer containing 50 mM sodium acetate at pH 5 was found to have a positive effect on the recovery of commercial fungal-derived cellulase and xylanase amended to switchgrass, the same buffer had a significant negative effect on enzyme extraction from solid fermentation samples colonized by the bacterium Acidothermus cellulolyticus. Xylanase activity was more affected by components in the extraction buffers compared to cellulase. This study demonstrated that extraction followed by diafiltration is important for assessing enzyme recovery from solid fermentation samples. Reduction in activity due to compounds present in the switchgrass extracts is reversible when the compounds are removed via diafiltration
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