Evaluation of the osmoregulatory function of taurine in brain cells

Summary Homogenous primary cultures of mouse astrocytes and cortical neurons were used to clarify the role of taurine in ion and osmoregulation in the CNS. This study indicates that both neurons and glial cells have uptake systems for taurine. The cell water content does not change during loading of cells with taurine. Chemical analysis indicates that part of the accumulated taurine is metabolized and that the product(s) are stored in the cells. Extracellular taurine (1 mM) has no effect on K⁺, Na⁺, Cl^-, or Ca²⁺ movements in astrocytes. However, astrocytes loaded to a taurine content which corresponds a concentration of 60 mM (corresponds to normal mouse cortex levels) show a 50% reduction in their K⁺ accumulation by carriers and a 100% increase in Ca²⁺ turnover rates. Movements of Ca²⁺ and K⁺ are involved in neurotransmission. It appears that taurine stored in glial cells, has an important effect on ion homeostasis in the CNS and may act indirectly on neuronal excitability.     

Body fluid changes, thirst and drinking in man during free access to water

To investigate whether human thirst and drinking during ad lib access to water occur in response to body fluid deficits, we obtained blood samples and visual analog scale thirst ratings from five healthy, volunteer, young men at hourly intervals and when they were thirsty during a normal working day. Although there were significant increases in ratings of thirst, pleasantness of drinking water, mouth dryness and unpleasantness of the taste in the mouth when subjects were thirsty enough to drink compared with intervening intervals, there were no concomitant changes in body fluid variables (microhematocrit, plasma osmolality and plasma sodium, potassium, protein and angiotensin II concentrations). Subjects drank mainly in association with eating and were not overhydrated as indicated by constantly hypertonic urine and significant tubular reabsorption of free water over the experimental period. The results indicate that during free access to water humans become thirsty and drink before body fluid deficits develop, perhaps in response to subtle oropharyngeal cues, and so provide evidence for anticipatory thirst and drinking in man.     

Long-lasting increase in the set point for cocaine self-administration after escalation in rats

Rationale: When access time to a continuous schedule of drug self-administration is restricted, animals tend to limit intake to a certain level over time and across doses. This observation suggests an endogenous constraint or set point that determines the individual’s preferred level of pharmacological effects. Objectives: To assess whether the transition to increased levels of drug intake is associated with a change in set point. Methods: Two groups of rats were trained on a 1-h continuous schedule of cocaine self-administration (250 μg/injection), after which access to cocaine was increased to 6 h in one group (Long Access or LgA rats) or kept to 1 h in the other group (Short Access or ShA rats). After 22 sessions on this regimen, different doses of cocaine were tested (31.25, 62.5, 125, and 250 μg/injection). For each dose, the post-response time-out period was reduced to 4 s to reduce any temporal limitations on self-injections and subjects were tested several times. Results: In LgA rats, the first hour intake escalated over time and eventually reached a level 200% greater than that of ShA rats. Though all rats maintained relatively constant intake across doses, LgA rats took nearly two times as much cocaine than ShA rats. When access to cocaine for LgA rats was reduced to 1 h, intake returned very slowly toward pre-escalation levels but was still elevated even after 2 months of reduced availability. Conclusions: These data suggest that the transition to escalated levels of intake is associated with a long-lasting change in cocaine set point. Received: 12 February 1999 / Final version: 21 May 1999     

Expression and characterization of αvβ5 integrin on intestinal macrophages

Macrophages play a crucial role in maintaining homeostasis in the intestine, but the underlying mechanisms have not yet been elucidated fully. Here, we show for the first time that mature intestinal macrophages in mouse intestine express high levels of αvβ5 integrin, which acts as a receptor for the uptake of apoptotic cells and can activate molecules involved in several aspects of tissue homeostasis such as angiogenesis and remodeling of the ECM. αvβ5 is not expressed by other immune cells in the intestine, is already present on intestinal macrophages soon after birth, and its expression is not dependent on the microbiota. In adults, αvβ5 is induced during the differentiation of monocytes in response to the local environment and it confers intestinal macrophages with the ability to promote engulfment of apoptotic cells via engagement of the bridging molecule milk fat globule EGF‐like molecule 8. In the absence of αvβ5, there are fewer monocytes in the mucosa and mature intestinal macrophages have decreased expression of metalloproteases and IL 10. Mice lacking αvβ5 on haematopoietic cells show increased susceptibility to chemical colitis and we conclude that αvβ5 contributes to the tissue repair by regulating the homeostatic properties of intestinal macrophages.     

Associations between serum amino acids and incident type 2 diabetes in Chinese rural adults

Background and aimsSome amino acids (AAs) may be associated with type 2 diabetes (T2DM). This study aimed to determine the associations of individual AAs with the development of T2DM in rural Chinese adults.Methods and resultsA cohort study of 1199 individuals aged 18 years or older was conducted from 2006 to 2008 in a rural community of Deqing, China, a repeated survey was done in 2015 and data linkage with the electronic health records system was performed each year for identifying new T2DM cases. A high-performance liquid chromatography approach was used to measure the baseline serum concentrations of 15 AAs. Cox proportional hazards models were used to examine the associations between AAs and the risk of incident T2DM. A total of 98 new T2DM cases were identified during the follow-up of 12 years on average. Among 15 AAs, proline was associated with an increased risk of incident T2DM after adjusted for age, sex, body mass index, fasting plasma glucose, family history of T2DM, smoking status, alcohol use, and history of hypertension, the adjusted hazard ratio for 1-standard deviation increment was 1.20 (95% confidence interval: 1.00, 1.43). The association tended to be more marked in subjects younger than 60 years and overweight/obese subjects. Among participants without hypertension, proline and phenylalanine were associated with an increased risk of incident T2DM, while aspartic acid was associated with a decreased risk.ConclusionSerum proline was associated with the risk of incident T2DM in rural Chinese adults and might be a potential predictor.     

Tone as a health concept: An analysis

Study designConcept analysis.IntroductionThis paper is a report on the analysis of the concept of tone in chiropractic.PurposeThe purpose of this paper is to clarify the concept of tone as originally understood by Daniel David Palmer from 1895 to 1914 and to monitor its evolution over time.MethodsData was sourced from Palmer's original work, published between 1895 and 1914. A literature search from 1980 to 2016 was also performed on the online databases CINHAL, PubMed and Scopus with key terms including ‘tone’, ‘chiropractic’, ‘Palmer’, ‘vitalism’, ‘health’, ‘homeostasis’, ‘holism’ and ‘wellness’. Finally hand-searches were conducted through chiropractic books and professional literature from 1906 to 1980 for any references to ‘tone’. Rodgers' evolutionary method of analysis was used to categorise the data in relation to the surrogates, attributes, references, antecedents and consequences of tone.ResultsA total of 49 references were found: five from publications by Palmer; three from the database searches, and; the remaining 41 from professional books, trade journals and websites.Major conclusionsThere is no clear interpretation of tone in the contemporary chiropractic literature. Tone is closely aligned with functional neurology and can be understood as an interface between the metaphysical and the biomedical. Using the concept of tone as a foundation for practice could strengthen the identity of the chiropractic profession.     

Clinical evaluation of insulin resistance and β-cell function by the homeostasis model assessment in patients with systemic lupus erythematosus

The aim of this preliminary study was to evaluate insulin resistance and secretion using homeostasis model assessment (HOMA) in patients with systemic lupus erythematosus (SLE). The fasting glucose and insulin concentrations, HOMA insulin resistance (IR), HOMA -cell, antidouble-stranded DNA antibodies (anti-dsDNA), C3, C4, and SLE disease activity index (SLEDAI) were determined in a total of 58 female SLE patients. All patients were classified into subgroups according to the presence of anticardiolipin antibodies (aCL+ vs. aCL-) and SLEDAI scores (SLEDAI <3 vs. SLEDAI >3). Results showed that SLE patients with and without aCL had significantly higher fasting insulin levels, HOMA IR, and HOMA -cells than controls. Similar results were also found in SLE patients with different disease activities. Pearsons correlation analysis showed that there was a highly significant correlation of HOMA IR with fasting insulin concentration in the SLE patients and SLE subgroups overall. However, HOMA -cells were positively correlated with HOMA IR and fasting insulin level, but negatively correlated with fasting glucose concentration in SLE patients overall. In conclusion, SLE patients, regardless of the presence of aCL and different disease activities, had a higher risk of insulin resistance and abnormal insulin secretion than age-matched healthy controls, based on fasting insulin concentration, HOMA IR, and HOMA -cells.Abbreviations HOMA Homeostasis model assessment - IGT Impaired glucose tolerance - IR Insulin resistance - NGT Normal glucose tolerance - SLE Systemic lupus erythematosus - SLEDAI SLE disease activity index