Enhancement of early human E rosette formation by cholinergic stimuli.

The effects of the cholinergic stimuli carbamylcholine (carbachol) and dibutyrl cyclic guanosine monophosphate (DBCGMP) were determined on both 'early' and 'total' E rosette formation. Ficoll-Hypaque-separated lymphocytes were preincubated with either carbachol or DBCGMP over a 10(-3) M to 10(-13) M dose range. Both agents significantly enhanced 'early', but not 'total' E rosette formation. Peak enhancement above control values occurred at 10(-7) M (72%) and 10(-9) M (69%) for carbachol and 10(-5) M (70%) and 10(-7) M (70%) for DBCGMP. Kinetic studies showed a rapid onset of enhancement (2.5 min) for carbachol, whereas DBCGMP required 15 min for significant enhancement to occur. The muscurinic nature of carbachol enhancement of E rosettes was demonstrated. Atropine at 10(-7) M completely abolished the carbachol effect while showing little inhibition of the DBCGMP effect on rosette formation. These studies indicate that the cholinergic stimuli carbachl and DBCGMP significantly enhance the 'early' E rosette former in man. Human T lymphocytes appear to have functional cholinergic receptors that can be blocked by the muscurinic antagonist atropine. The role of the cyclic nucleotides and their stimulants on the immune system is incompletely understood, but it would appear that they are extremely important in the differentiation and function of the T lymphocyte. E rosette formation may be a useful model in man for studying the effects of the cyclic nucleotides on the human T lymphocyte.     

ENaC, renal sodium excretion and extracellular ATP

Sodium balance determines the extracellular fluid volume and sets arterial blood pressure (BP). Chronically raised BP (hypertension) represents a major health risk in Western societies. The relationship between BP and renal sodium excretion (the pressure/natriuresis relationship) represents the key element in defining the BP homeostatic set point. The renin–angiotensin–aldosterone system (RAAS) makes major adjustments to the rates of renal sodium secretion, but this system works slowly over a period of hours to days. More rapid adjustments can be made by the sympathetic nervous system, although the kidney can function well without sympathetic nerves. Attention has now focussed on regulatory mechanisms within the kidney, including extracellular nucleotides and the P2 receptor system. Here, we discuss how extracellular ATP can control renal sodium excretion by altering the activity of epithelial sodium channels (ENaC) present in the apical membrane of principal cells. There remains considerable controversy over the molecular targets for released ATP, although the P2Y₂ receptor has received much attention. We review the available data and reflect on our own findings in which ATP-activated P2Y and P2X receptors make adjustments to ENaC activity and therefore sodium excretion.     

Tamoxifen and Ovarian Function

Background

Some studies suggest that the clinical parameter “amenorrhea” is insufficient to define the menopausal status of women treated with chemotherapy or tamoxifen. In this study, we investigated and compared the ovarian function defined either by clinical or biological parameters in pre-menopausal breast cancer patients treated with tamoxifen administered as adjuvant therapy.

Materials and Methods

Between 1999 and 2003, 138 premenopausal patients consecutively treated for early breast cancer were included. Sixty-eight received tamoxifen in monotherapy as the only adjuvant systemic treatment (Group I) and 70 were treated with tamoxifen after adjuvant chemotherapy (Group II). All patients had a confirmed premenopausal status based on clinical parameters and hormonal values at study entry. They were followed prospectively every 3 months for 3 years: menses data, physical examination and blood tests (LH, FSH, 17-beta-estradiol). Vaginal ultrasonography was carried out every 6 months. After 3 years, prospective evaluation was completed and monitoring of ovarian function was performed as usual in our institution (1x/year). All data were retrospectively evaluated in 2011.

Results

Three patients were excluded from the study in group I and 2 were excluded in group II. Patients were divided into 4 subgroups according to clinical data, i.e. menses patterns. These patterns were assessed by questionnaires. a: Regular menses (>10 cycles/year) b: Oligomenorrhea (5 to 9 cycles/year) c: Severe oligomenorrhea (1 to 4 cycles/year) d: Complete amenorrhea Estrogen levels did not appear to have any impact on disease-free survival rates after 3 or 8 years. FSH values were also documented and analyzed. They exhibited the same profile as estradiol values.

Conclusions

Amenorrhea is an insufficient parameter to define menopausal status in patients receiving tamoxifen. Low estradiol levels must be coupled with other biological parameters to characterize endocrine status. These data are very important for the choice of endocrine therapy.     

A widespread plant-fungal-bacterial symbiosis promotes plant biodiversity,plant nutrition and seedling recruitment

Highly diverse microbial assemblages colonize plant roots. It is still poorly understood whether different members of this root microbiome act synergistically by supplying different services (for example, different limiting nutrients) to plants and plant communities. In order to test this, we manipulated the presence of two widespread plant root symbionts, arbuscular mycorrhizal fungi and nitrogen-fixing rhizobia bacteria in model grassland communities established in axenic microcosms. Here, we demonstrate that both symbionts complement each other resulting in increased plant diversity, enhanced seedling recruitment and improved nutrient acquisition compared with a single symbiont situation. Legume seedlings obtained up to 15-fold higher productivity if they formed an association with both symbionts, opposed to productivity they reached with only one symbiont. Our results reveal the importance of functional diversity of symbionts and demonstrate that different members of the root microbiome can complement each other in acquiring different limiting nutrients and in driving important ecosystem functions.     

Mucin secretion by the human colon cell line LS174T is regulated by bile salts

We recently reported that bile salts play a role in the regulation of mucin secretion by cultured dog gallbladder epithelial cells. In this study we have examined whether bile salts also influence mucin secretion by the human epithelial colon cell line LS174T. Solutions of bile salts were applied to monolayers of LS174T cells. Mucin secretion was quantified by measuring the secretion of [3H]GlcNAc labeled glycoproteins. Both unconjugated bile salts as well as taurine conjugated bile salts stimulated mucin secretion by the colon cells in a dose-dependent fashion. Hydrophobic bile salts were more potent stimulators than hydrophilic bile salts. Free (unconjugated) bile salts were more stimulatory compared with their taurine conjugated counterparts. Stimulation of mucin secretion by LS174T cells was found to occur at much lower bile salt concentrations than in the experiments with the dog gallbladder epithelial cells. The protein kinase C activators PMA and PDB had no stimulatory effect on mucin secretion. We conclude that mucin secretion by the human colon epithelial cell line LS174T is regulated by bile salts. We suggest that regulation of mucin secretion by bile salts might be a common mechanism, by which different epithelia protect themselves against the detergent action of bile salts, to which they are exposed throughout the gastrointestinal tract.      

Evaluation of the rectal V30 parameter in patients diagnosed with postoperative endometrial cancer

BackgroundThe present paper reports on analysis of 184 patients who were diagnosed with endometrial cancer. The main objective of this study was to address parameter V_rec(30Gy) which determines a volume of the rectum irradiated with a dose of 30 Gy during radiotherapy.Materials and methodsAll patients were irradiated with an IMRT technique on linear accelerators. The planning target volume (PTV) contour was determined by a radiation oncologist. The clinical target volume (CTV) was drawn on CT images obtained in a prone position. For statistical analysis, appropriate tests (e.g. the Shapiro-Wilk, Wilcoxon) were used.Results and discussionThe performed analysis showed that the recommended condition for V_rec(30Gy) is met only in 3% of patients and the observed median value exceeds 90%. The obtained results were compared with the studies in which the V_rec(30Gy) values were related to various radiotherapy techniques.ConclusionsThe analysis showed that the condition for V_rec(30Gy) is satisfied in the case of only 3% of patients. Due to the difficulty with meeting the condition, it should be reconsidered based on real results.