In silico evidence for gluconeogenesis from fatty acids in humans

The question whether fatty acids can be converted into glucose in humans has a long standing tradition in biochemistry, and the expected answer is “No”. Using recent advances in Systems Biology in the form of large-scale metabolic reconstructions, we reassessed this question by performing a global investigation of a genome-scale human metabolic network, which had been reconstructed on the basis of experimental results. By elementary flux pattern analysis, we found numerous pathways on which gluconeogenesis from fatty acids is feasible in humans. On these pathways, four moles of acetyl-CoA are converted into one mole of glucose and two moles of CO₂. Analyzing the detected pathways in detail we found that their energetic requirements potentially limit their capacity. This study has many other biochemical implications: effect of starvation, sports physiology, practically carbohydrate-free diets of inuit, as well as survival of hibernating animals and embryos of egg-laying animals. Moreover, the energetic loss associated to the usage of gluconeogenesis from fatty acids can help explain the efficiency of carbohydrate reduced and ketogenic diets such as the Atkins diet.

That sugar can be converted into fatty acids in humans is a well-known fact. The question whether the reverse direction, i.e., gluconeogenesis from fatty acids, is also feasible has been a topic of intense debate since the end of the 19^th century. With the discovery of the glyoxylate shunt that allows this conversion in some bacteria, plants, fungi and nematodes it has been considered infeasible in humans since the corresponding enzymes could not be detected. However, by this finding only a single route for gluconeogenesis from fatty acids has been ruled out. To address the question whether there might exist alternative routes in humans we searched for gluconeogenic routes from fatty acids in a metabolic network comprising all reactions known to take place in humans. Thus, we were able to identify several pathways showing that this conversion is indeed feasible. Analyzing evidence concerning the detected pathways lends support to their importance during times of starvation, fasting, carbohydrate reduced and ketogenic diets and other situations in which the nutrition is low on carbohydrates. Moreover, the energetic investment required for this pathway can help to explain the particular efficiency of carbohydrate reduced and ketogenic diets such as the Atkins diet.

Cost of dementia in Switzerland

QUESTIONS UNDER STUDY

The aim of this study was (a) to estimate the cost of dementia in Switzerland, (b) to compare the average annual cost for people with dementia who live at home and those living in an institution and (c) to analyse how the average cost per person with dementia who lives at home increases with the severity of dementia.

METHODS

This prevalence-based cost-of-illness study from a societal perspective combined top-down and bottom-up approaches and included both direct and indirect costs of dementia. Cost estimations were based on Swiss national statistics and surveys, as well as international reviews and expert interviews.

RESULTS

The total annual cost of dementia amounted up to CHF 6.3 billion for the year 2007. Together, institutional and informal care accounted for over 90% of the cost. The average annual cost was estimated at CHF 55'300 per person with dementia who lives at home and at CHF 68'900 per person who lives in an institution. The cost per person living at home with severe dementia was nearly five times the cost per person with mild dementia.

CONCLUSIONS

The present study indicates that dementia imposes a considerable economic burden on Swiss society. The cost of dementia is dominated by the costs of care. Diagnosis and treatment related costs are minor. These findings are consistent with contemporary international studies on the subject. The contribution of informal caregivers is substantial since they account for 44% of the total cost of dementia (based on market cost valuation). Given demographic developments in Switzerland, healthcare decision making should have an interest in securing this potential for the future.

Injury risk factors in junior tennis players: a prospective 2-year study

The aim was to investigate injury risk factors in junior tennis players. Fifty-five players, 35 boys and 20 girls, answered a questionnaire about training habits, time of exposure, previous injuries and equipment factors. A battery of clinical tests and functional performance tests were also carried out. All tennis-related injuries that occurred during a 2-year period were identified and recorded. An injury was defined as an injury if it was impossible to participate in regular tennis training or playing matches during at least one occasion, a time loss injury. Potential injury risk factors were tested in a forward stepwise logistic regression model for injury. Thirty-nine players sustained totally 100 new and recurrent injuries. Injuries to the lower extremity were the most common ones (51%) followed by the upper extremity (24%) and the trunk (24%). Injured players performed more singles per week (P<0.0001) and played more tennis hours per year (P=0.016) than the uninjured players. Playing tennis more than 6 h/week was found to be a risk factor for back pain. A previous injury regardless of location was identified as an injury risk factor, and a previous injury to the back was a risk factor for back pain.

Proximal lower limb vein thrombosis following vipera berus hand bite

Vipera berus has a wide geographical distribution throughout Central and Northern Europe. The symptoms after a bite usually are mild, life threatening symptoms are mainly described in children. We describe a case of popliteal vein thrombosis of the right leg after systemic envenoming with Vipera berus venom after a bite in the right hand by a female Vipera berus in the alpine region of Styria, Austria. Changes of the plasmatic coagulation system were obvious in our patient. These changes were due to an activation of the coagulation system and might be the reason for the thrombotic event in this usually healthy young male person.

Variable cell responses to P. gingivalis lipopolysaccharide

Porphyromonas gingivalis is a major etiological agent of chronic periodontal diseases, the virulence of which has been attributed to different factors, including lipopolysaccharide (LPS). We investigated the differential responses induced by P. gingivalis LPS stimulation of human umbilical vein endothelial cells and human oral epithelial cells. RT-PCR analysis showed that P. gingivalis LPS used Toll-like receptor 2 (TLR2) to activate epithelial cells and Toll-like receptor 4 (TLR4) to activate endothelial cells. Both cell types were stimulated by P. gingivalis LPS to produce pro-inflammatory cytokines. Cytokine Array assay showed that although patterns of cytokine expression were similar in both cell types, some cytokines were specifically secreted by the endothelial cells, and others were specific to epithelial cells. These results support the idea that the same LPS preparation can act as a TLR2 or TLR4 agonist, depending on TLR expression of the host cell, inducing cytokine profiles that differ according to the cell type.

Phase transitions in solid solution series bismutocolumbite – stibiocolumbite (Bi-Sb)(Nb0.79Ta0.21)O4

The crystal structure of bismutocolumbite, Bi(Nb0.79Ta0.21)O4 with orthorhombic (sp. gr. Pnna) stibio-tantalite structure type at ambient conditions has been de-termined at 2.59 and 9.56 GPa, and 23oC. Crystal data and results of structure refinement using powder X-ray diffrac-tion and Rietveld analysis for Bi-rich stibiocolumbite, (Sb0.52Bi0.48)(Nb0.71Ta0.29)O4, are reported. At the pressure ~2.9 GPa bismutocolumbite exhibits phase transition which is accompanied by the change of its symmetry: sp. gr. Pnna is replaced by the sp. gr. Pn21 a. This kind of transformation is anticipated at ambient pressure in bismutocolumbite- stibiocolumbite solid solution series in the compounds with Sb/(Bi+Sb) ratio higher than 0.52 which characterises the studied crystals of stibiotantalite. Similarly with scheelite-like BiVO4, in bismutocolumbite the reduction of the unit cell volume under HP is mainly a result of Bi-O polyhedral compression, which is accompanied by a rearrangement of (Nb,Ta)O6 octahedra within octahedral sheets parallel to (010). (Nb,Ta)O6 octahedra remain rigid with smaller change in size at high pressure.

Lattice parameters of La3Ga5SiO14 as a function of hydrostatic pressure

Langasite (La3Ga5SiO14) crystallizes in the polar space group P321. Here we report the pressure dependence of the lattice parameters at high hydrostatic pressures up to 10.2 GPa. The results presented in terms of compressibility agree well with results from measurements of the elastic constants. According to a Birch-Murnaghan equation of state, the bulk modulus and its pressure derivative are 134.6(2) and 2.8(1) GPa, respectively. The compression of langasite crystals is anisotropic, the c/a-ratio appears to be a linear function of the pressure applied according to c/a = 0.62460(6) + 0.00055(1)* p/GPa. Altogether four single crystals have been investigated. Two of them showed a splitting of reflections (hhl). This splitting reaches a maximum at approximately 9 GPa and proved to be reversible.

Influence of high hydrostatic pressure on lattice parameters of a single crystal of La3Nb0.5Ga5.5O14

Unit-cell parameters of La3Nb0.5Ga5.5O14 (langanite) have been determined at a number of pressures up to 23GPa in diamond anvil high pressure cells with single crystal X-ray diffraction techniques. The anisotropic behaviour of unit cell parameters of langanite is caused by differences of bonding strength in direction parallel to the a- and c-axis. Within the investigated pressure range, the c/a-ratio increases from 0.6232 to 0.6503. The volume compressibility of trigonal langanite (space group P321) is the 0.007 GPa-1, with calculated bulk modulus of 145(3)GPa (B'0=1.4(8)). At a pressure of 12.4(3)GPa a first-order phase transition was detected, characterised by a discontinuity in the pressure dependence of lattice parameter c. The high-pressure phase (presumably monoclinic, A2) with a volume compressibility of 0.011 GPa-1 (B0=93(2) GPa, B'0=1.9(9)) is more compressible as compared to the initial phase due to an abnormal pressure dependence of lattice parameter a.

Ultrahigh-resolution soft-x-ray microscopy with zone plates in high orders of diffraction

We present an x-ray optical approach to overcome the current limitations in spatial resolution of x-ray microscopes. Our new BESSY full-field x-ray microscope operates with an energy resolution up to E/DeltaE=10(4). We demonstrate that under these conditions it is possible to employ high orders of diffraction for imaging. Using the third order of diffraction of a zone plate objective with 25 nm outermost zone width, 14 nm lines and spaces of a multilayer test structure were clearly resolved. We believe that high-order imaging paves the way towards sub-10-nm real space x-ray imaging.

Family quality of life among families with a member who has an intellectual disability: an exploratory examination of key domains and dimensions of the revised FQOL Survey

BACKGROUND

The Family Quality of Life Survey (FQOLS-2006) was developed as the result of increased interest in family quality of life (FQOL) among families with a member who has an intellectual disability (ID). The instrument includes nine life domains and six dimensions reflecting the main areas and characteristics of FQOL. The aim of the current study was to provide a descriptive analysis of the domains and dimensions of the survey and to explore their relationship to one another and to global satisfaction.

METHOD

A convenience sample of 35 participants with a family member who had ID completed the FQOLS-2006 in a large urban centre in Canada. The data were analysed using descriptive analyses.

RESULTS

The findings showed that although participants differentiated between different domains and dimensions, as reflected in their variability, stability was also found. For example, support from others was rated lowest across most dimensions, while family relationships and health of the family were generally rated higher.

CONCLUSIONS

The findings strengthen the importance of examining both the overall perception of FQOL as well as the perceptions in individual life domains. Moreover, they highlight the need to examine each life domain according to its various dimensions. In sum, the results call for further examination of the FQOLS-2006 as a useful tool for assessing FQOL and for implementing services based on it.

Effects of long-term bromocriptine treatment on catecholamine excretion and on circulatory adaptation to orthostasis and to exercise in patients with hyperprolactinemia

Sympatho-adrenally regulated mechanisms of the circulatory system have been studied in seven patients with hyperprolactinemia in order to evaluate the effects of long-term (1-3 months) treatment with bromocriptine. Before treatment catecholamine excretion was within the normal range. Blood volume was low and there was a marked heart rate reaction to orthostasis. ECG showed no abnormalities. Blood pressure and ECG reaction during exercise were normal. The blood pressure heart rate response to handgrip was less marked than in healthy young men. During bromocriptine treatment, serum prolactin levels normalized in all but one patient. Total catecholamine excretion was lowered. Body weight diminished. Resting heart rate and blood pressure fell significantly. Blood volume per kg body weight remained unchanged as did the orthostatic heart rate increase. The circulatory response to handgrip was less marked than before therapy. It seems that long-term bromocriptine therapy provokes a cardiovascular pattern reflecting an inhibition of sympatho-adrenal activity.

Normal growth hormone secretion is rare after microsurgical normalization of growth hormone levels in acromegaly

The effect of microsurgery on growth hormone (GH) secretion was studied in 34 patients with acromegaly. All patients showed enlarged sella volumes according to encephalography and macroadenomas at surgery. Preoperative GH levels were elevated in all 34 patients and 14 had concomitant hyperprolactinemia. There was a correlation between basal GH levels and sella size. Visual field defects, suprasellar extension, long duration of the disease, hyperprolactinemia and aneuploidy were noted in patients with low as well as high levels of GH preoperatively. The average reduction of GH levels in the total series was 71 +/- 21% (mean +/- SD). A notably similar reduction of GH levels was seen regardless of preoperative GH levels, concomitant hyperprolactinemia, visual field defects, size of the adenoma, invasive growth or increasing experience of the surgeon. Therefore, normal GH levels after surgery were reached mainly in patients with moderate GH increments preoperatively. GH levels were normalized by surgery in 15 patients but only four of these showed normal GH response to TRH and iota-dopa tests. Thus, only four patients (12%) fulfilled these criteria for cure of GH homeostasis.

Prolactinomas in men: clinical characteristics and the effect of bromocriptine treatment

Thirty-seven men with prolactin (PRL) producing pituitary adenomas were studied to elucidate if patient's delay might cause the predominance of large tumours in men as compared to women in whom microadenomas predominate. We found two clinical subgroups; one presented with short duration of symptoms, dominated by local signs from the growth of notably large tumours, the other exhibited a long history of disease with hypogonadism as the dominating symptom. There was a correlation between tumour size and PRL levels. The age at the time of diagnosis showed no correlation to duration of symptoms, size of adenoma or PRL levels. Four patients with small adenomas, moderate hyperprolactinemia and short duration of symptoms showed signs of hypergonadotropic hypogonadism. Surgery or irradiation, performed in 14 patients, did not normalize PRL levels. Bromocriptine was equally beneficial in the two clinical subgroups, improving clinical symptoms and normalizing PRL levels in all but three patients. The study shows that the predominance of large tumours in men does not depend on patient's or doctor's delay, but on a high frequency of presumably rapidly growing PRL producing tumours. In the majority of patients, these tumours do not give signs of hypogonadism before the tumour is revealed by local signs of tumour growth.

Urinary cyclic AMP corrected for glomerular filtration rate in the differential diagnosis of hypercalcemia

To evaluate the usefulness of urinary cyclic AMP (U-cAMP) expressed as nmol/100 ml glomerulus filtrate (GF) when discriminating various hypercalcemic states, we studied 99 patients. Patients with primary hyperparathyroidism (PHPT) showed a positive correlation between individual S-calcium levels and U-cAMP, nmol/100 ml GF (females r=0.49, n=40, p less than 0.01 and males r=0.91, n=7 p less than 0.001). There was also a correlation between U-cAMP, nmol/100 ml GF, and the weight of the adenomas (females r=0.36, n=32, p less than 0.05) and males r=0.79, n=6, p less than 0.05). Patients with PHPT and normal renal function excreted more U-cAMP than controls, 6.0 +/- 1.6 versus 4.3 +/- 1.0 nmol/100 ml GF (mean +/- SD). Of 47 patients with PHPT and normal renal function, 29 showed values below the upper normal limit, 6.3 nmol/100 ml GF (mean +/-2 SD), of the control group; the overlap was 62%. When U-cAMP was expressed as mumol/24 hours, the overlap was 40/47 (85%) and, when expressed as mumol/g creatinine, 31/47 (66%). Three patients with sarcoidosis and two with malignancies and hypercalcemia showed excretory values of U-cAMP, nmol/100 ml GF, above the upper normal limit. Patients with acromegaly or prolactinoma showed normal values of U-cAMP, nmol/100 ml GF. The present data indicate that all three types of determinations of urinary cAMP based on 24 hour urine collections are of little value in the differential diagnosis of hypercalcemic states.

Cushing's syndrome due to an ACTH-producing neuroendocrine tumour in the nasal roof

A patient with ectopic adrenocorticotrophic hormone (ACTH) production from a neuroendocrine tumour of the nasal roof is presented. By indirect immunoperoxidase techniques the tumour cells were shown to be distinctly positive for ACTH and beta-endorphin but negative for other peptides derived from pro-opiomelanocortin. Neither corticotropin releasing hormone (CRF) found in some tumours associated with ectopic Cushing's syndrome, nor gastrin immunoreactivity, which coexists with ACTH in normal rat pituitary and in rat and human gastrointestinal cells, were demonstrable in the tumour. A review of other, previously recognized locations of CRF/ACTH producing tumours is given to increase the awareness of the ectopic Cushing's syndrome, which may lack the classical features and is characterized by fulminant clinical course, extreme fatigue, weakness, pale facial swelling, oedema and hypokalaemic alkalosis.

Cortisol insufficiency caused by electroconvulsive therapy? A case report

A 30-year-old woman was treated with a series of electroconvulsive therapy (ECT) due to a personality disorder with depressive symptoms. Three days after the last ECT, anisocoria was noticed. It subsided after 2 days, and attacks of syncope, vertigo, anorexia and weight loss started. These symptoms ceased by administration of cortisone acetate and fluoro-cortisone. During an observation time of five years, repeated attempts to omit the cortico-steroids or reduce the cortisone dose to less than 20 mg/day have resulted in immediate symptoms of cortisol deficiency. Plasma adrenocorticotrophin (ACTH) and cortisol and urinary cortisol were low during cortisol withdrawal. Cortisol response to ACTH stimulation and cortisol and ACTH response to hypoglycemia were normal. The cortisol deficiency was considered to be due to a defect in the central nervous regulation of ACTH secretion. As it occurred in close connection to ECT, it seems likely that the treatment induced a defect, or aggravated a preexisting one, in neural pathways controlling corticotrophin-releasing factor and ACTH secretion.