bluuebunny/crossref_metadata_2025 huggingface dataset:
A fundamental conflict of care: Nurses’ accounts of balancing patients' sleep with taking vital sign observations at night
Authors: Hope Joanna , Recio‐Saucedo Alejandra , Fogg Carole , Griffiths Peter , Smith Gary B , Westwood Greta , Schmidt Paul E
Published: December 2017

Aims and objectives

To explore why adherence to vital sign observations scheduled by an early warning score protocol reduces at night.

Background

Regular vital sign observations can reduce avoidable deterioration in hospital. early warning score protocols set the frequency of these observations by the severity of a patient's condition. Vital sign observations are taken less frequently at night, even with an early warning score in place, but no literature has explored why.

Design

A qualitative interpretative design informed this study.

Methods

Seventeen semi‐structured interviews with nursing staff working on wards with varying levels of adherence to scheduled vital sign observations. A thematic analysis approach was used.

Results

At night, nursing teams found it difficult to balance the competing care goals of supporting sleep with taking vital sign observations. The night‐time frequency of these observations was determined by clinical judgement, ward‐level expectations of observation timing and the risk of disturbing other patients. Patients with COPD or dementia could be under‐monitored, while patients nearing the end of life could be over‐monitored.

Conclusion

In this study, we found an early warning score algorithm focused on deterioration prevention did not account for long‐term management or palliative care trajectories. Nurses were therefore less inclined to wake such patients to take vital sign observations at night. However, the perception of widespread exceptions and lack of evidence regarding optimum frequency risks delegitimising the early warning score approach. This may pose a risk to patient safety, particularly patients with dementia or chronic conditions.

Relevance to clinical practice

Nurses should document exceptions and discuss these with the wider team. Hospitals should monitor why vital sign observations are missed at night, identify which groups are under‐monitored and provide guidance on prioritising competing expectations. early warning score protocols should take account of different care trajectories.
Resilience and positive affect contribute to lower cancer‐related fatigue among Chinese patients with gastric cancer
Authors: Zou Guiyuan , Li Ye , Xu Ruicai , Li Ping
Published: December 2017

Aims and objectives

To investigate the prevalence of cancer‐related fatigue and explore the relationship between resilience, positive affect, and fatigue among Chinese patients with gastric cancer.

Background

Cancer‐related fatigue is the most distressing symptom reported frequently by cancer patients during both treatment and survival phases. Resilience and positive affect as vital protective factors against cancer‐related fatigue have been examined, but the underlying psychological mechanisms are not well understood.

Design

A cross‐sectional study.

Methods

Two hundred and three gastric cancer patients were enrolled from three hospitals in China. The Cancer Fatigue Scale, the positive affect subscale of the Positive and Negative Affect Schedule and the Connor‐Davidson Resilience Scale (CD‐RISC10) were administered. Hierarchical linear regression modelling was conducted to examine the association between resilience and cancer‐related fatigue, and the mediating effect of positive affect.

Results

The incidence of clinically relevant fatigue among patients with gastric cancer was 91.6%. Regression analysis showed that resilience was negatively associated with cancer‐related fatigue, explaining 15.4% of variance in cancer‐related fatigue. Mediation analysis showed that high resilience was associated with increased positive affect, which was associated with decreased cancer‐related fatigue.

Conclusions

Cancer‐related fatigue is prevalent among patients with gastric cancer. Positive affect may mediate the relationship between resilience and cancer‐related fatigue.

Relevance to clinical practice

Interventions that attend to resilience training and promotion of positive affect may be the focus for future clinical and research endeavours.
Unit Root Testing with Unstable Volatility
Authors: Beare Brendan K.
Published: December 2017

Unit root test statistics may not have the usual asymptotic properties when the variance of innovations is unstable. In particular, persistent changes in volatility can cause the size to differ from the nominal level. We propose a class of modified unit root test statistics that are robust to the presence of unstable volatility. The modification is achieved by purging heteroskedasticity from the data using a kernel estimate of volatility before the application of standard tests. In the absence of deterministic trend components, this approach delivers test statistics that achieve standard asymptotics under the null hypothesis of a unit root. When the data are homoskedastic, the local power of unit root tests is unchanged by our modification. We use Monte Carlo simulations to compare the finite sample performance of our modified tests with that of existing methods of correcting for unstable volatility.
The complex physiology of Cellvibrio japonicus xylan degradation relies on a single cytoplasmic β‐xylosidase for xylo‐oligosaccharide utilization
Authors: Blake Andrew D. , Beri Nina R. , Guttman Hadassa S. , Cheng Raymond , Gardner Jeffrey G.
Published: December 2017

Lignocellulose degradation by microbes plays a central role in global carbon cycling, human gut metabolism and renewable energy technologies. While considerable effort has been put into understanding the biochemical aspects of lignocellulose degradation, much less work has been done to understand how these enzymes work in an in vivo context. Here, we report a systems level study of xylan degradation in the saprophytic bacterium Cellvibrio japonicus. Transcriptome analysis indicated seven genes that encode carbohydrate active enzymes were up‐regulated during growth with xylan containing media. In‐frame deletion analysis of these genes found that only gly43F is critical for utilization of xylo‐oligosaccharides, xylan, and arabinoxylan. Heterologous expression of gly43F was sufficient for the utilization of xylo‐oligosaccharides in Escherichia coli. Additional analysis found that the xyn11A, xyn11B, abf43L, abf43K, and abf51A gene products were critical for utilization of arabinoxylan. Furthermore, a predicted transporter (CJA_1315) was required for effective utilization of xylan substrates, and we propose this unannotated gene be called xntA (xylan transporter A). Our major findings are (i) C. japonicus employs both secreted and surface associated enzymes for xylan degradation, which differs from the strategy used for cellulose degradation, and (ii) a single cytoplasmic β‐xylosidase is essential for the utilization of xylo‐oligosaccharides.
Myasthenia gravis: the role of complement at the neuromuscular junction
Authors: Howard James F.
Published: December 2017

Generalized myasthenia gravis (gMG) is a rare autoimmune disorder characterized by skeletal muscle weakness caused by disrupted neurotransmission at the neuromuscular junction (NMJ). Approximately 74–88% of patients with gMG have acetylcholine receptor (AChR) autoantibodies. Complement plays an important role in innate and antibody‐mediated immunity, and activation and amplification of complement results in the formation of membrane attack complexes (MACs), lipophilic proteins that damage cell membranes. The role of complement in gMG has been demonstrated in animal models and patients. Studies in animals lacking specific complement proteins have confirmed that MAC formation is required to induce experimental autoimmune MG (EAMG) and NMJ damage. Complement inhibition in EAMG models can prevent disease induction and reverse its progression. Patients with anti‐AChR+ MG have autoantibodies and MACs present at NMJs. Damaged NMJs are associated with more severe disease, fewer AChRs, and MACs in synaptic debris. Current MG therapies do not target complement directly. Eculizumab is a humanized monoclonal antibody that inhibits cleavage of complement protein C5, preventing MAC formation. Eculizumab treatment improved symptoms compared with placebo in a phase II study in patients with refractory gMG. Direct complement inhibition could preserve NMJ physiology and muscle function in patients with anti‐AChR+ gMG.
Early major complications after bariatric surgery in the USA, 2003–2014: a systematic review and meta‐analysis
Authors: Chang S.‐H. , Freeman N. L. B. , Lee J. A. , Stoll C. R. T. , Calhoun A. J. , Eagon J. C. , Colditz G. A.
Published: December 2017

The effectiveness of bariatric surgery has been well‐studied. However, complications after bariatric surgery have been understudied. This review assesses <30‐d major complications associated with bariatric procedures, including anastomotic leak, myocardial infarction and pulmonary embolism. This review included 71 studies conducted in the USA between 2003 and 2014 and 107,874 patients undergoing either gastric bypass, adjustable gastric banding or sleeve gastrectomy, with mean age of 44 years and pre‐surgery body mass index of 46.5 kg m−2. Less than 30‐d anastomotic leak rate was 1.15%; myocardial infarction rate was 0.37%; pulmonary embolism rate was 1.17%. Among all patients, mortality rate following anastomotic leak, myocardial infarction and pulmonary embolism was 0.12%, 0.37% and 0.18%, respectively. Among surgical procedures, <30‐d after surgery, sleeve gastrectomy (1.21% [95% confidence interval, 0.23–2.19%]) had higher anastomotic leak rate than gastric bypass (1.14% [95% confidence interval, 0.84–1.43%]); gastric bypass had higher rates of myocardial infarction and pulmonary embolism than adjustable gastric banding or sleeve gastrectomy. During the review, we found that the quality of complication reporting is lower than the reporting of other outcomes. In summary, <30‐d rates of the three major complications after either one of the procedures range from 0% to 1.55%. Mortality following these complications ranges from 0% to 0.64%. Future studies reporting complications after bariatric surgery should improve their reporting quality.
Antioxidant supplementation, effect on post‐thaw spermatozoan function in three sturgeon species
Authors: Li P , Xi MD , Du H , Qiao XM , Liu ZG , Wei QW
Published: December 2017

Contents

High levels of reactive oxygen species (ROS), which may be associated with reduced sperm quality, can be detected during cryopreservation of sperm of some species. Our objective was to investigate whether the addition of antioxidants to cryopreservation extenders influenced post‐thaw sperm characteristics and fertility in Acipenser dabryanus, Acipenser sinensis and Acipenser baerii. Prior to freezing, sperm samples were diluted with a base extender as control or in extender supplemented with catalase (CAT), glutathione (GSH), cysteine (NAC), ascorbic acid (VC) or their paired combinations. Protective concentrations of CAT, GSH and VC in the three species were 25 U/ml, 0.25‐0.5 mg/ml and 0.5 mg/ml, respectively. Cysteine showed no protective effect against ROS. The addition of CAT, GSH and VC positively affected either acrosome or membrane integrity of post‐thawed sperm in the three species, as well as spermatozoan motility in A. sinensis. The combination of antioxidants did not show a positive synergistic effect. This study suggested that the use of antioxidants in the cryopreservation of sturgeon sperm has potential to decrease intracellular ROS, and consequently preserve acrosome and membrane integrity, as well as spermatozoan motility.
Kiai Haji Ahmad Shah: Peranannya dalam Memantapkan Perkembangan Islam di Johor
Authors: Md Sirat Siti Maimon , Mohd. Yusof Farahwahida , Thukiman Kassim , Sacckani Saleha
Published: December 2017

In the development of a society and a nation-state, the aspect of leadership plays a key role. Moreover, the leadership comes from the figures who are called ulama’ or Muslim scholars. Kiai Haji Ahmad Shah is a renowned scholar in Johor. He served as Cadi or an Islamic Judge in several districts in Johor before being appointed Chief Islamic Judge of Johor. He was born in 1901 in Kampung Rimba Terjun, Pontian, Johor. His excellence in mastering various fields of knowledge and the talent of leadership began since childhood. His personal excellence attracted the public to explore the teachings of Islam, and he became a role model to amny leaders as well as murabbi or educators of today. The persistence of Kiai Haji Ahmad Shah in facing the challenge of developing and strengthening the faith of Muslims in the era before independence were the main focus of this study. This also shows the Islamic leadership in Kiai Haji Ahmad Shah; a leader who really believes in the "Leadership by Example"
Spark Advance Modeling of Hydrogen-Fueled Spark Ignition Engines Using Combustion Descriptors
Authors: Verma Saket , Das L. M.
Published: December 2017

In-cylinder pressure-based combustion descriptors have been widely used for engine combustion control and spark advance scheduling. Although these combustion descriptors have been extensively studied for gasoline-fueled spark ignition (SI) engines, adequate literature is not available on use of alternative fuels in SI engines. In an attempt to partially address this gap, present work focuses on spark advance modeling of hydrogen-fueled SI engines based on combustion descriptors. In this study, two such combustion descriptors, namely, position of the pressure peak (PPP) and 50% mass fraction burned (MFB) have been used to evaluate the efficiency of the combustion. With a view to achieve this objective, numerical simulation of engine processes was carried out in computational fluid dynamics (CFD) software ANSYS fluent and simulation data were subsequently validated with the experimental results. In view of typical combustion characteristics of hydrogen fuel, spark advance plays a very crucial role in the system development. Based on these numerical simulation results, it was observed that the empirical rules used for combustion descriptors (PPP and 50% MFB) for the best spark advance in conventional gasoline fueled engines do not hold good for hydrogen engines. This work suggests revised empirical rules as: PPP is 8–9 deg after piston top dead center (ATDC) and position of 50% MFB is 0–1 deg ATDC for the maximum brake torque (MBT) conditions. This range may vary slightly with engine design but remains almost constant for a particular engine configuration. Furthermore, using these empirical rules, spark advance timings for the engine are presented for its working range.
Response to Comment on “Rapid cooling and cold storage in a silicic magma reservoir recorded in individual crystals”
Authors: Cooper Kari M. , Till Christy B. , Kent Adam J. R. , Costa Fidel , Rubin Allison E. , Gravley Darren , Deering Chad , Cole Jim , Bose Maitrayee
Published: December 2017

In a recent paper, we used Li concentration profiles and U-Th ages to constrain the thermal conditions of magma storage. Wilson and co-authors argue that the data instead reflect control of Li behavior by charge balance during partitioning and not by experimentally determined diffusion rates. Their arguments are based on (i) a coupled diffusion mechanism for Li, which has been postulated but has not been documented to occur, and (ii) poorly constrained zircon growth rates combined with the assumption of continuous zircon crystallization.
Taking the lead
Beyond Politics
Michael P. Vandenbergh and Jonathan M. Gilligan
Cambridge University Press, 2017. 493 pp.
Authors: Victor David G.
Published: December 2017

Faced with government inaction, private firms emerge as major players in climate change mitigation
Parasite-Mediated Degradation of Synthetic Ozonide Antimalarials Impacts
In Vitro
Antimalarial Activity
Authors: Giannangelo Carlo , Stingelin Lukas , Yang Tuo , Tilley Leann , Charman Susan A. , Creek Darren J.
Published: December 2017

The peroxide bond of the artemisinins inspired the development of a class of fully synthetic 1,2,4-trioxolane-based antimalarials, collectively known as the ozonides. Similar to the artemisinins, heme-mediated degradation of the ozonides generates highly reactive radical species that are thought to mediate parasite killing by damaging critical parasite biomolecules. We examined the relationship between parasite dependent degradation and antimalarial activity for two ozonides, OZ277 (arterolane) and OZ439 (artefenomel), using a combination of
in vitro
drug stability and pulsed-exposure activity assays. Our results showed that drug degradation is parasite stage dependent and positively correlates with parasite load. Increasing trophozoite-stage parasitemia leads to substantially higher rates of degradation for both OZ277 and OZ439, and this is associated with a reduction in
in vitro
antimalarial activity. Under conditions of very high parasitemia (∼90%), OZ277 and OZ439 were rapidly degraded and completely devoid of activity in trophozoite-stage parasite cultures exposed to a 3-h drug pulse. This study highlights the impact of increasing parasite load on ozonide stability and
in vitro
antimalarial activity and should be considered when investigating the antimalarial mode of action of the ozonide antimalarials under conditions of high parasitemia.
Interstitial lung disease secondary to Cetuximab in bladder cancer: an Oncologist’s perspective
Authors: Price Louise , Glynn Patricia , Zarkar Anjali
Published: December 2017

A wide variety of cytotoxic medications cause interstitial lung disease (ILD). For the first time, we describe ILD in an 82-year-old woman with muscle invasive bladder cancer 10 days after receiving cetuximab as part of a novel trial. She had no significant medical history or drug allergies, had good exercise tolerance and a 5 pack-year smoking history. She received neoadjuvant chemotherapy (gemcitabine, cisplatin) with a good response on MRI. She was eligible for a phase 2 trial of cetuximab with chemotherapy and radiotherapy for muscle invasive bladder cancer (TUXEDO), in which the trial arm used cetuximab plus standard chemoradiotherapy to the bladder (64 grey in 32 fractions plus mitomycinandfluorouracil). Ten days after her third infusion of cetuximab, she was presented with type 1 respiratory failure. Thoracic CT scan demonstrated new widespread ground glass change in the lungs. She received high-dose steroids (prednisolone 1 mg/kg), broad spectrum antibacterial cover and non-invasive ventilation. She survived to be discharged with residual respiratory failure.
Stenotrophomonas maltophilia: an emerging multidrug-resistant opportunistic pathogen in the immunocompromised host
Authors: Baumrin Emily , Piette Evan W , Micheletti Robert G
Published: December 2017

Stenotrophomonas maltophiliais a multidrug-resistant opportunistic pathogen with increasing prevalence and high morbidity and mortality. In addition to its classic association with pulmonary infections,S. maltophiliacan cause skin and soft tissue infections with varying clinical presentations. We describe the case of a man in his 30s with B-cell acute lymphoblastic leukaemia who presented with a solitary patch of faint but tender purpura found to have rapidly progressiveS. maltophiliainfection diagnosed on skin biopsy.S. maltophiliainfection should be considered in the cutaneous evaluation of the immunocompromised host.
Comprehensive, integrated approaches to suicide prevention: practical guidance
Authors: Caine Eric D , Reed Jerry , Hindman Jarrod , Quinlan Kristen
Published: December 2017

Background

Efforts in the USA during the 21st century to stem the ever-rising tide of suicide and risk-related premature deaths, such as those caused by drug intoxications, have failed. Based primarily on identifying individuals with heightened risk nearing the precipice of death, these initiatives face fundamental obstacles that cannot be overcome readily.

Objective

This paper describes the step-by-step development of a comprehensive public health approach that seeks to integrate at the community level an array of programmatic efforts, which address upstream (distal) risk factors to alter life trajectories while also involving health systems and clinical providers who care for vulnerable, distressed individuals, many of whom have attempted suicide.

Conclusion

Preventing suicide and related self-injury morbidity and mortality, and their antecedents, will require a systemic approach that builds on a societal commitment to save lives and collective actions that bring together diverse communities, service organisations, healthcare providers and governmental agencies and political leaders. This will require frank, data-based appraisals of burden that drive planning, programme development and implementation, rigorous evaluation and a willingness to try-fail-and-try-again until the tide has been turned.
Invariant entanglement and generation of quantum correlations under global dephasing
Authors: Karpat Göktuğ
Published: December 2017

We investigate the dynamics of quantum entanglement and more general quantum correlations quantified via negativity and local quantum uncertainty, respectively, for two-qubit systems undergoing Markovian collective dephasing. Focusing on a two-parameter family of initial two-qubit density matrices, we study the relation of the emergence of the curious phenomenon of time-invariant entanglement and the dynamical behavior of local quantum uncertainty. Developing an illustrative geometric approach, we demonstrate the existence of distinct regions of quantum entanglement for the considered initial states and identify the region that allows for completely frozen entanglement throughout the dynamics, accompanied by generation of local quantum uncertainty. Furthermore, we present a systematic analysis of different dynamical behaviors of local quantum uncertainty, such as its sudden change or smooth amplification, in relation with the dynamics of entanglement.
Influence of deposition temperature on structural, morphological, and optical properties of ZnS thin films
Authors: Temel Sinan
Published: December 2017

ZnS thin films were deposited onto glass substrates by chemical bath deposition (CBD) technique at different deposition temperatures (75, 80, 85, 90 °C) with non-toxic complexing agent tri-sodium citrate. Effects of deposition temperature on structural, morphological, and optical properties of thin films were investigated by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and ultraviolet–visible spectroscopy, respectively. The XRD results show that all produced ZnS thin films have cubic structure. The calculated grain size values are between 13 and 26 nm. It was observed that the grain size values increase and crystallization of films improve as the deposition temperature increases. The FESEM images reveal that film surfaces are formed by almost homogeneously dispersed nanostructured particles. Optical characterization results show that ZnS thin films have high transmittance of about 80% in the range of 400–800 nm with band gap energy values between 3.52 and 3.65 eV. As the deposition temperature increases, the band gap energy values increase. According to these results, it was observed that the structural, morphological, and optical properties of ZnS films vary depending on the deposition temperature.
Determining the understanding levels of pre-service physics teachers about magnetic induction
Authors: Dinçer Tuğbanur , Özcan Özgür
Published: December 2017

Energy is a phenomenon that cannot be created or destroyed, but can be changed from one form into another. Electromagnetic induction is a good example where the same principle of energy conversion is applied. The induced current resulting from electromagnetic induction is related to some physical variables. These variables can change either directly or inversely proportionally to each other. However, semi-structured interviews with 20 pre-service physics teachers have shown that these relations are quite complex. For these reasons, pre-service physics teachers have some difficulty in establishing these relations and therefore they are at different understanding levels. Within the scope of this study, understanding levels of pre-service physics teachers about electromagnetic induction were determined.
Determination of radioactivity levels of salt minerals on the market
Authors: Yüksel Zeynep , Tufan M. Çağatay
Published: December 2017

Human beings have been continuously exposed to natural radioactive rays since their existence in the world. From the end of the 19th century, besides natural sources, mankind has been exposed inevitably to artificial radioactive sources with the development of technology. Radiation has beneficial effects on human beings but also can have harmful consequences if overexposed. Therefore, it is important for both public and governmental institutions to know radioactivity levels, particularly in foodstuffs, for human health. There have been rumours among the public that the level of radioactivity in salt minerals exported from abroad is high. In this study, the radioactivity levels of imported and domestic salts on the market shelves have been determined by using gamma spectrometry units with HPGe detector.
Four-body bound state calculations using three-dimensional low-momentum effective interaction Vlow-k
Authors: Radin M. , Mohseni H. , Nazari F. , Hadizadeh M. R.
Published: December 2017

In this paper, we solve the coupled Yakubovsky integral equations for four-body (4B) bound state using the low-momentum effective two-body interaction [Formula: see text] in a three-dimensional (3D) approach, without using a partial wave (PW) decomposition. The renormalization group (RG) evolved interaction is constructed from spin-independent Malfliet–Tjon potential using the Lee–Suzuki method. The cutoff dependence of the 4B binding energy and wave function is investigated for a wide range of the momentum cutoff [Formula: see text] of [Formula: see text] interaction from 1.0 to 8.0[Formula: see text][Formula: see text].
Effect of iron stores and hysterectomy on iron absorption and distribution in pregnant mice.
Authors: Batey R , Gallagher N
Published: December 2017

Intestinal uptake (U) and transport (T) of 50Fe from a 1-mug oral dose was studied in the mouse. U increased to a similar degree in both pregnant and iron-deficient animals. The increase in T was greater in pregnant than in iron-deficient mice. In iron-loaded pregnant mice, U increased to levels found in pregnant animals, whereas T increased, but by a lesser amount. Termination of pregnancy by delivery or hysterectomy at days 20-21 resulted in a fall in U and T to normal levels within 24 h. Eighty percent of iron transported across the intestine in pregnancy was recovered from the fetuses, compared to 6.7% recovered in the maternal liver. Hepatic uptake was lower in pregnant than in iron-deficient mice or in postpartum mice with persisting iron deficiency. Hepatic uptake by the maternal liver after an intravenous dose of 2 mug 50Fe increased to levels in iron-deficient mice within 5 min of hysterectomy. The results demonstrate an effect of pregnancy on intestinal iron transport and its distribution that was dependent on the presence of fetuses and placentas.
HCO3 transport in rat jejunum: relationship to NaCl and H2O transport in vivo.
Authors: Podesta R B , Mettrick D F
Published: December 2017

HCO3- absorption and its association with Na+ absorption has been studied in the rat jejunum in vivo, using a single-pass perfusion technique. The method of disequilibrium pH, the only valid way of demonstrating jejunal H+ secretion, was used to distinguish between an HCO3- pump and H+ secretion as the mechanism of HCO3- absorption. HCO3- stimulated Na+ absorption; Na+ deletion inhibited HCO3 absorption, decreased luminal acidification, and decreased the level of luminal PCO2. These results confirmed an Na+:H+ cation exchange, the possible mechanism of which is discussed in terms of results using other tissues. Na+-dependent HCO3-absorption made up a larger part of total HCO3-absorption as the luminal HCO3-concentrations diminished, although the precise degree of Na+-dependency could not be determined because of the unstirred layer effect. The mechanism of Na+-independent HCO3-absorption was not established, but it was not affected by PD, Cl-, or H2O movements. Glucose-stimulated and HCO3-stimulated Na+ absorption were less than additive. The physiological importance of HCO3-stimulated Na+ absorption in the acidic postprandial jejunum is probably due entirely to the effect of free CO2 in the lumen.
Fatty liver in hypervitaminosis A: synthesis and release of hepatic triglycerides.
Authors: Singh M , Singh V N
Published: December 2017

Feeding large doses (30,000 IU/100 g body wt per day) of vitamin A to young rats for 2 days produced fatty liver, caused a stimulation of oxidation and esterification of [1-14C]palmitate by liver slices, and increased the activity of hepatic palmitoyl-CoA synthetase. Under similar conditions, however, release of hepatic triglycerides into the plasma, as judged from the post-Triton triglyceridemia, remained unaffected. It is indicated by the present findings that excessive intake of vitamin A produces fatty liver by stimulating the synthesis of triglycerides in liver without affecting the rate of secretion of hepatic triglycerides. An involvement of altered oxidation of fatty acids in the liver can also be ruled out because in hypervitaminosis A this process is increased rather than decreased as required for fatty liver production.
Intestinal absorption of zinc: a role for a zinc-binding ligand in milk.
Authors: Duncan J R , Hurley L S
Published: December 2017

This study examined the proposal that a low molecular weight, zinc-binding ligand (ZBL) in certain milks is important for zinc absorption in the neonatal period. Ten-day-old rats, in which intestinal ZBL is absent, fed (by stomach intubation) 65Zn-labeled ZBL from rat milk, absorbed significantly more 65Zn than those fed free 65ZnCl2 or bovine milk fractions. ZBL from human milk appeared to have an intermediate effect, possibly due to species specificity. 65Zn was found in the ZBL fraction in intestinal mucosa of 10-day-old rats fed rat or human milk fractions, but not in those fed bovine milk or free 65ZnCl2. In contrast, in 18-day-old rats, which have an endogenous intestinal ZBL, there were no differences in zinc absorption, and any of the labeled milk fractions or free 65Zn caused localization of 65Zn in the ZBL fraction of intestinal mucosa. These results support the hypothesis that the intestinal ZBL plays a role in zinc absorption and that in the neonatal period before its development the milk ZBL is valuable for this function. This mechanism may be important in normal human infants as well as in acrodermatitis enteropathica patients.
Insulin antagonistic effects of epinephrine and glucagon in the dog.
Authors: Sacc� L , Eigler N , Cryer P E , Sherwin R S
Published: December 2017

The effect of glucagon and/or epinephrine on the response to physiologic insulin infusion was evaluated in dogs. Insulin alone produced a transient fall (50%) in glucose output, a threefold rise in glucose clearance, and a decline in plasma glucose, which then stabilized (40--45 mg/dl) afer 1 h. Glucagon infusion prevented the fall in glucose output, but had no effect on insulin-induced elevations in glucose clearance. The fall in plasma glucose was delayed (20 min), but late hypoglycemia was unaltered. Epinephrine infusion blocked the fall in glucose output as well as the insulin-induced rise in glucose clearance and uptake. Thus, while epinephrine and glucagon were equally effective in preventing the fall in glucose output induced by insulin, epinephrine was more effective in preventing insulin-induced hypoglycemia by virtue of its direct inhibitory action on insulin-stimulated glucose utilization. Simultaneous addition of glucagon and epinephrine increased glucose output twofold, suppressed glucose clearance, and caused a 15--30 mg/dl increase in plasma glucose despite ongoing hyperinsulinemia. Our data thus indicate that synergistic hormone interactions may play a role in the counterregulation of insulin hypoglycemia.
Secretory effects of gastrins on isolated perfused porcine pancreas
Authors: Jensen S. L. , Rehfeld J. F. , Holst J. J. , Fahrenkrug J. , Nielsen O. V. , Schaffalitzky de Muckadell O. B.
Published: December 2017

The effects of the four main forms of gastrin (component I, gastrin-34, gastrin-17, and gastrin-14) on insulin, glucagon, and exocrine secretion were measured on the isolated perfused porcine pancreas. All gastrins were studied in concentrations ranging from 10(-11) to 10(-8) M. Depending on the glucose concentration in the perfusate, all four gastrins increased insulin or glucagon secretion in a dose-dependent manner in concentrations above 10(-10) M. These concentrations are slightly above the arterial concentrations in normal pig and man, but they correspond to gastrin concentrations measured in patients with achlorhydria and gastrinomas. The exocrine secretion was stimulated by all gastrins in a dose-dependent manner. The lowest concentrations that stimulated flow rate significantly were within the physiologic range, 10(-11) and 10(-10) M. All gastrins induced maximal flow rate at a concentration of 10(-9) M. The sulfated form of gastrin-17 had the greatest efficacy. The results indicate that all gastrins may influence the exocrine secretion under normal conditions and the endocrine secretion in diseases with endogenous hypergastrinemia.
Influence of experimental diabetes and insulin on matrix-induced cartilage and bone differentiation
Authors: Weiss R. E. , Reddi A. H.
Published: December 2017

The influence of streptozotocin-induced diabetes on discrete stages of matrix-induced endochondral bone formation has been investigated. Mesenchymal cell proliferation was inhibited in diabetic rats as evidenced by a 65% reduction of ornithine decarboxylase (ODC) activity and a 56% reduction of [3H]thymidine incorporation per microgram DNA compared to nondiabetic controls; the inhibition was prevented by insulin treatment. In diabetic animals, chondrogenesis on day 7 was reduced by 49% compared to control animals as assessed by 35SO4 incorporation. Exogenous insulin was stimulatory to cartilage development when present during days 0 through 4 (mesenchymal cell proliferation). Calcification of cartilage and osteogenesis were reduced by more than 50% in diabetic rats and corrected by insulin as measured by alkaline phosphatase activity and 45Ca incorporation. Decreased in vivo endochondral bone growth and development during diabetes is the result of 1) inhibition of insulin-dependent mesenchymal cell proliferation, 2) decreased and delayed cartilage formation due to impaired mesenchymal cell proliferation, 3) decreased and delayed vascular invasion prior to chondrolysis and osteogenesis, and 4) reduced insulin-dependent calcification and ossification.
Circadian sleep and feeding patterns in the rat: possible dependence on lipogenesis and lipolysis
Authors: Danguir J. , Nicolaidis S.
Published: December 2017

Sleep and feeding patterns were continuously recorded in rats under intravenous saline (control) and alternating insulin-epinephrine (experimental) infusions. The infusion of insulin (lipogenetic hormone) during the normally light period (0800-1600) replaced by epinephrine (lipolytic hormone) during the normally lipogenetic dark period (1600-0800) resulted in a complete inversion of the normal circadian distribution of sleep and feeding patterns and also of their correlation. Insulin infusion resulted in low blood glucose and glycerol levels whereas epinephrine increased these physiological parameters. Different control conditions showed that the fluctuations of sleep and feeding were dependent on the rate of utilization of the circulating metabolites at the cellular level. These results together with previous data suggest that the relation between sleep and feeding and their concomitant circadian fluctuation are possibly modulated by a common factor, namely the metabolic rate that is influenced by the lipogenesis/lipolysis rate.
Influence of low-energy diets on whole-body protein turnover in obese subjects
Authors: Garlick P. J. , Clugston G. A. , Waterlow J. C.
Published: December 2017

Rates of whole-body protein synthesis and breakdown in obese subjects have been measured by three methods: constant intravenous infusion of [1-14C]leucine, repeated oral doses of [15N]glycine, and a single oral dose of [15N]glycine. The three techniques gave similar rates of synthesis and breakdown when the subjects received a normal diet containing 8.0 MJ and 70 g protein. After 3 wk on a low-energy diet (2.1 MJ), repeat measurements were made. When the low-energy diet contained protein (50 g), rates of protein synthesis and breakdown were little different from those with the normal diet. When the low-energy diet contained no protein, there was a 40% fall in whole-body protein synthesis and a smaller fall in breakdown. Excretion of 3-methylhistidine in the urine did not change with either low-energy diet. We conclude that the decrease in dietary energy from 8.0 to 2.1 MJ did not influence protein turnover, but that dietary protein was necessary if rates of whole-body protein synthesis and breakdown were to be maintained.
Intravenous infusions of nutrients and sleep in the rat: an ischymetric sleep regulation hypothesis
Authors: Danguir J. , Nicolaidis S.
Published: December 2017

Unrestrained food-deprived rats received their daily caloric needs through continuous or discontinuous intravenous infusions of specific nutritive substances over a period of 3 consecutive days each, and the effect on sleep monitored by electroencephalogram was examined. Continuous glucose or lipid infusions did not affect the daily sleep quotas. Amino-acid infusion brought about a significant increase in paradoxical sleep (PS), whereas slow-wave sleep (SWS) remained unchanged. Rats that received the highly nutritive composite solution showed significant increase in both SWS and PS. The same increase in SWS and PS was observed when exogenous insulin was coinfused with continuous infusion of glucose or when glucose infusions were discontinuous. These findings suggest that sleep might be related to both the nature and the degree of utilization of the circulating metabolites. A model for the action on sleep of nutrients at the systemic level was proposed; only when substances are metabolized is there a direct effect on sleep mechanisms.
Relationship between plasma osmolality and plasma vasopressin in human subjects
Authors: Hammer M. , Ladefoged J. , Olgaard K.
Published: December 2017

The relationship between plasma osmolality (pOsm) and plasma vasopressin (pAVP) was studied in 13 human subjects during dehydration. The fit of linear, log-linear, parabolic, and exponential models was tested. For all of the data, the nonlinear models had the best fit. However, when individual differences in either gain or threshold were allowed for, the linear models were better than log-linear models. Finally, analyses were made with individual data points. Linear models had the best fit in half of the subjects, whereas for the others the parabolic model gave the best fit. For those subjects investigated in the low range of the osmoregulatory curve, a linear relationship was found, whereas, for those having the most pronounced increase in pOsm, the most significant improvement was found with the parabolic model. This finding indicates that the relationship is not stable during dehydration in the whole range and that hypovolemia probably can influence the secretion rate and/or metabolic clearance rate and thereby the relationship.
Insulin binding and glucose uptake of adipocytes in rats adapted to hypergravitational force
Authors: Kobayashi M. , Mondon C. E. , Oyama J.
Published: December 2017

Rats were exposed to 4.15 g for 1 yr and weight and age matched, and lean noncentrifuged rats were used as control groups. Rats exposed to chronic hypergravity (hypergravic rats) were found to show lower ambient insulin levels, greater food intake with smaller body weight gain, and decreased size of isolated adipocytes. The ability of adipocytes from the hypergravic rats to bind insulin was increased. With Scatchard analysis, both number and affinity of receptors were increased. In contrast to the increased binding, glucose transport was found to be decreased in adipocytes from these animals. However, when the data were expressed as a percentage of maximal effect, the half maximal insulin effect for both the hypergravic and lean control groups was produced at an insulin concentration of 0.23 +/- 0.02 ng/ml, which was lower than the insulin concentration of 0.31 +/- 0.02 ng/ml for the weight-matched control group (P less than 0.05). This increased insulin sensitivity in the hypergravic group was accounted for by an increased number of receptors.
Phosphoribosylpyrophosphate bioavailability in diabetic rat renal cortex in vivo
Authors: Cortes P. , Verghese C. P. , Venkatachalam K. K. , Schoenberger A. M. , Levin N. W.
Published: December 2017

Experimental diabetes induces increased content of RNA and UTP in the renal cortex. Studies were designed to assess the bioavailability of 5-phosphoribosyl-1-pyrophosphate (PRPP) in the diabetic renal cortex because PRPP is an important determinant of the de novo synthesis of nucleotides. The tissue bioavailability of PRPP determines the effects of orotate or adenine administration on UTP, ATP, and GTP content and on the incorporation of labeled precursors into UTP and ATP. Diabetic and control rats with chronic intravenous cannulas were infused over 2.5-24 h with orotate or adenine. Orotate administration induced greater decreases in ATP and GTP and in labeled adenine incorporation into ATP concomitant with smaller increases in UTP in controls than in diabetic animals. Adenine administration induced a greater decrease of labeled orotate incorporation into UTP and a smaller increase in ATP in controls than in diabetic animals. Prolonging the adenine infusion resulted in disappearance of these differences. The results are compatible with greater initial bioavailability of PRPP in the diabetic renal cortex than in controls but with a rate of maximal PRPP generation that is the same in both tissues.
Uridine triphosphate and RNA synthesis during diabetes-induced renal growth
Authors: Cortes P. , Levin N. W. , Dumler F. , Rubenstein A. H. , Verghese C. P. , Venkatachalam K. K.
Published: December 2017

UTP, CTP, and RNA synthesis were studied in the renal cortex of diabetic and control rats in vivo. The incorporation of UTP into RNA (nmol/h DNA) was used as estimate of RNA synthesis rate. Two to three days after streptozotocin injection, UTP and CTP ppol size and orotate incorporation into UTP and RNA were greater in diabetic animals than in controls. In addition, RNA content and RNA synthesis rate were increased. These changes were corrected by insulin infusion. In diabetic animals, additional increases in UTP pool, RNA content, and RNA synthesis rate followed contralateral nephrectomy. This increase in RNA content was greater than in uninephrectomized controls. The changes in the diabetic renal cortex were not accompanied by increased plasma concentrations of growth hormone. The increase in RNA content in the diabetic renal cortex is probably due to increased RNA synthesis. Increased synthesis of pyrimidines and expansion of the UTP pool may make this substrate more readily available for the synthesis of UDP sugars and may facilitate the synthesis of basement membrane in diabetes.
Effects of vitamin D metabolites on bovine parathyroid hormone release in vitro
Authors: Chertow B. S. , Baker G. R. , Henry H. L. , Norman A. W.
Published: December 2017

We evaluated the effects of 1 alpha,25-dihydroxycholecalciferol (1,25(OH)2D3), 24R,25-dihydroxycholecalciferol (24,25(OH)2D3), and 25-hydroxycholecalciferol (25(OH)D3) on the release of parathyroid hormone (PTH). Bovine parathyroid tissues were incubated in vitro for 4 h in low-calcium (1.0 mM) medium. 1,25(OH)2D3 ((10(-9)-10(-12)M), 24,25(OH)2D3 (10(-6)-10(-8)M), and 25(OH)D3 (5 X 10(-7)-5 X 10(-9)M) inhibited PTH release. Inhibition by all metabolites was concentration and time dependent. On a molar basis, 1,25(OH)2D3 was the most potent metabolite, being at least 100 times more potent than 24,25(OH)2D3 and 25(OH)D3; 24,25(OH)2D3 was about 5 times more potent than 25(OH)D3 at concentrations producing 65% inhibition. Inhibition by high concentrations of metabolites was evident by 1 h of incubation; inhibition was progressive throughout incubation, and maximal suppression to 30-40% of control occurred during the fourth and final hour of incubation. 1,25(OH)2D3 (10(-11) M), a low concentration that did not inhibit secretion, transiently stimulated release. In conclusion, under conditions of low-calcium-stimulated PTH release, 1,25(OH)2D3, 24,25(OH)2D3, and 25(OH)D3 inhibited PTH release, 1,25(OH)2D3 was the most potent inhibitor.
Effects and interactions of 24R,25(OH)2D3 and 1,25(OH)2D3 on bone
Authors: Malluche H. H. , Henry H. , Meyer-Sabellak W. , Sherman D. , Massry S. G. , Norman A. W.
Published: December 2017

The effects of various combinations of therapy with 1 alpha,25-dihydroxycholecalciferol (1,25(OH)2D3) and 24R,25-dihydroxycholecalciferol (24R,25(OH)2D3) on structural and dynamic parameters of bone were evaluated in 40 chicks raised on a vitamin D-deficient diet from time of hatching and supplemented with the dihydroxylated metabolites. The results showed that: 1) the maintenance of volumetric density of bone is dependent on the presence of 1,25(OH)2D3, 2) lack of 1,25(OH)2D3 is associated with an increase in the number of osteocytes per unit volume of bone, most probably due to decreased amounts of bone formed by each osteoblast before becoming an osteocyte, 3) adequate quantities of either 24R,25(OH)2D3 or 1,25(OH)2D3 are needed to prevent accumulation of osteoid or the production of endosteal fibrosis, and 4) maintenance of normal tetracycline label width requires both hydroxylated compounds with one of them in sufficient amounts. The data of this study demonstrate that the integrity of certain parameters of bone structure could be maintained only with 1,25(OH)2D3, others with either dihydroxylated metabolites, and still others with a combination of both. These data underscore the biological activity of 24R,25(OH)2D3 by demonstrating its effectiveness on bone.
Stereospecific stimulation of brown adipocyte respiration by catecholamines via beta 1-adrenoreceptors
Authors: Bukowiecki L. , Follea N. , Paradis A. , Collet A.
Published: December 2017

Regulation of respiration by catecholamines was studied in adipocytes isolated from interscapular brown adipose tissue of warm-acclimated rats by rapid digestion of collagenase. (-)-Norepinephrine stimulated adipocyte respiration 10–12 times above basal values in less than 3 min. (Vmax = 410 +/- 29.5 nmol O2 . min-1 . 10(-6) cells-1). Stimulated respiration remained stable for at least 20 min, provided that cells were incubated in balanced salt media containing bicarbonate. The maximal capacity of total brown adipose tissue for norepinephrine-stimulated respitarion was estimated at 1.5 ml O2/min per rat. beta-Adrenergic agonists increased calorigenesis stereospecifically with an order of potency expected for respiratory stimulation via adrenoceptors of the beta 1-subtype: (-)-isoproterenol (1/2 Vmax = 2 nM) greater than (-)-norepinephrine (1/2 Vmax = 20 nM) approximately equal to (-)-epinephrine (1/2 Vmax = 40 nM) greater than corresponding (+)-stereoisomers. The alpha-adrenergic agonist phenylephrine (1/2 Vmax = 5 microM) stimulated adipocyte respiration as rapidly and as effectively as beta-agonists. Although alpha-adrenoreceptors are present in brown adipose tissue, studies with alpha- and beta-adrenergic antagonists revealed that norepinephrine elicits thermogenesis at physiological concentrations (less than or equal to 1 microM) predominantely via beta 1-adrenergic pathways.