Systemic bile acid sensing by G protein-coupled bile acid receptor 1 (GPBAR1) promotes PYY and GLP-1 release

BACKGROUND AND PURPOSE

Nutrient sensing in the gut is believed to be accomplished through activation of GPCRs expressed on enteroendocrine cells. In particular, L-cells located predominantly in distal regions of the gut secrete glucagon-like peptide 1 (GLP-1) and peptide tyrosine-tyrosine (PYY) upon stimulation by nutrients and bile acids (BA). The study was designed to address the mechanism of hormone secretion in L-cells stimulated by the BA receptor G protein-coupled bile acid receptor 1 (GPBAR1).

EXPERIMENTAL APPROACH

A novel, selective, orally bioavailable, and potent GPBAR1 agonist, RO5527239, was synthesized in order to investigate L-cell secretion in vitro and in vivo in mice and monkey. In analogy to BA, RO5527239 was conjugated with taurine to reduce p.o. bioavailability yet retaining its potency. Using RO5527239 and tauro-RO5527239, the acute secretion effects on L-cells were addressed via different routes of administration.

KEY RESULTS

GPBAR1 signalling triggers the co-secretion of PYY and GLP-1, and leads to improved glucose tolerance. The strong correlation of plasma drug exposure and plasma PYY levels suggests activation of GPBAR1 from systemically accessible compartments. In contrast to the orally bioavailable agonist RO5527239, we show that tauro-RO5527239 triggers PYY release only when applied intravenously. Compared to mice, a slower and more sustained PYY secretion was observed in monkeys.

CONCLUSION AND IMPLICATIONS

Selective GPBAR1 activation elicits a strong secretagogue effect on L-cells, which primarily requires systemic exposure. We suggest that GPBAR1 is a key player in the intestinal proximal-distal loop that mediates the early phase of nutrient-evoked L-cell secretion effects.

Conscious pain mapping by laparoscopy in women with chronic pelvic pain

OBJECTIVE

To evaluate the findings and outcomes of laparoscopic conscious pain mapping in women with unsuccessfully treated chronic pelvic pain.

METHODS

Fifty consecutive women with at least one prior procedure for chronic pelvic pain had conscious pain mapping. Operative findings and clinical outcomes were documented. Preoperative and postoperative pain levels were evaluated using visual analog scales.

RESULTS

Conscious pain mapping was successful in 35 cases (70%). Twenty-nine patients had 42 specific positive sites, and six patients had diffuse visceroperitoneal pelvic tenderness. Adhesions and endometriosis accounted for 45% of positive lesions or sites. About half of women with endometriosis or adhesions mapped pain specifically to those lesions. For endometriosis, histologic but not visual diagnosis predicted positive mapping. Specific viscera accounted for 36% of positively mapped sites. Diagnoses of chronic visceral pain syndrome were suggested by the findings in 16 (46%) patients whose mapping was successful. Mean +/- standard deviation visual analog scale pain levels were 8.7 +/- 1.2 preoperatively and 5.5 +/- 3.7 postoperatively. Twenty-two women (44%) had decreased pain postoperatively and eight (16%) were pain-free.

CONCLUSION

Conscious pain mapping can be done with reasonable success in women with prior surgical evaluations and treatments for chronic pelvic pain. Chronic visceral pain syndrome, adhesions, and endometriosis were the most common diagnoses.

In vitro analysis of venom from the wasp Nasonia vitripennis: susceptibility of different cell lines and venom-induced changes in plasma membrane permeability

The lethal effects of crude venom prepared from the ectoparasitic wasp Nasonia vitripennis were examined with cultured cells from six insect and two vertebrate species. Venom caused cells from Sarcophaga peregrina (NIH SaPe4), Drosophila melanogaster (CRL 1963), Trichoplusia ni (TN-368 and BTI-TN-5B1-4), Spodoptera frugiperda (SF-21AE), and Lymantria dispar (IPL-Ldfbc1) to round up, swell, and eventually die. Despite similar sensitivities and overlapping LC50 values [0.0004-0.0015 venom reservoir equivalents (VRE)/microl], profound differences were noted at the onset of cytotoxicity among the six insect cell lines: over 80% of the NIH SaPe4 and SF21AE cells were nonviable within 1 h after addition of an LC99 dose of venom, whereas the other cells required a 5-10-fold longer incubation period to produce mortality approaching 100%. In contrast, cells from the grass frog, Rana pipiens (ICR-2A), and goldfish, Carassius auratus (CAR), showed little sensitivity to the venom: six venom reservoir equivalents were needed to induce 50% mortality in ICR-2A cells [50% lethal concentration (LC50) = 0.067 VRE/microl), and 9 VRE did not yield sufficient mortality in CAR cells for us to calculate an LC50. All susceptible cells showed similar responses when incubated with wasp venom: retraction of cytoplasmic extensions (when present), blebbing of the plasma membrane, swelling of the plasma and nuclear membranes, condensation of nuclear material, and eventual cell death attributed to lysis. The rate of swelling and lysis in NIH SaPe4 and BTI-TN-5B1-4 cells exposed to venom appeared to be dependent on the diffusion potential of extracellular solutes (Na+ = choline > sucrose > or = raffinose > K+), which is consistent with a colloid-osmotic lysis mechanism of cell death. When T. ni cells were cotreated with venom and the K+ channel blocker 4-aminopyridine, cell swelling and lysis increased with increasing drug concentration. In contrast, cells from S. peregrina were protected from the effects of the venom when treated in a similar manner. Addition of certain divalent cations (Zn+2 and Ca+2) to the extracellular media 1 h postvenom incubation rescued both BTI-TN-5B1-4 and NIH SaPe4 cells, suggesting that protection was gained from closure of open pores rather than prevention of pore formation. Venom from N. vitripennis displayed no hemolytic activity toward sheep erythrocytes, supporting the view that venom intoxication is not by a nondiscriminate mechanism. A possible mode of action of the venom is discussed.

Plasma renin activity levels influence the effect of converting enzyme inhibitors in preserving renal function in hypertension

OBJECTIVE

To study the effect of treatment with cilazapril versus nifedipine on the glomerular filtration rate (GFR), microalbumin excretion rate (mu Alb) and baseline plasma renin activity (PRA) levels in non-diabetic or diabetic essential hypertension.

DESIGN AND METHODS

Thirty-four moderate essential hypertensives and thirty-two type II diabetic hypertensives with currently normal renal function completed the study, receiving treatment with a converting enzyme inhibitor (CEI, 5-10 mg/day cilazapril) or a non-CEI (20-40 mg slow-release nifedipine three times a day) during a 12-month controlled follow-up study.

RESULTS

Either treatment induced a similar reduction in blood pressure. Patients with PRA > 3 ng/ml per h treated with cilazapril showed a proportional increase in GFR, whereas in those treated with a non-CEI there was a decline in GFR after 8 and 12 months. Only diabetic patients treated with cilazapril showed a mu Alb reduction associated with a stable GFR.

CONCLUSION

PRA predicts the effect of CEI preserving renal function in essential and diabetic hypertension.

Water quality problems in Nogales, Sonora

This article presents the results of a transboundary water quality monitoring program at the two Nogales area in the Arizona-Sonora border region. The program was carried out jointly in 1990 by U.S. and Mexican institutions. The results show pollution problems due to deficiencies in Nogales, Sonora municipal sewerage system, causing not only sewage spills in several parts of the city but also creating occasional transboundary problems. The results also showed potential illegal dumping of industrial hazardous waste (VOCs) into Nogales' municipal sewerage system. All of the organic compounds found in the sewage samples are solvents frequently used by the border industry. Occasional brakes of pipes spill the pollutants into the Nogales Wash, a water stream that runs parallel to Nogales' main sewerage line. Samples of the municipal water system showed no traces of pollutants. However, two rounds of samples detected concentrations of VOCs in wells used to supply water by trucks to low income neighborhoods in Nogales, Sonora. Ironically, the pollution detected in these wells has a greater impact in low income groups of the city that pay three to four times more per liter of water they consume, than the rest of the inhabitants with clean water from the municipal system.

Overdrive prolongation of refractoriness and fatigue in the early stages of human bundle branch disease

OBJECTIVES

The aim of this study was to assess the response of refractoriness in normal and diseased human bundle branches to changes in cycle length, as well as during a long period of continuous overdrive pacing.

BACKGROUND

The anterograde refractory period of the bundle branches in patients with functional bundle branch block shortens as the rate is increased. The rate-dependent response of refractoriness in diseased bundle branches is quite different. However, this difference has not been precisely delineated, and its physiologic meaning is uncertain.

METHODS

Refractoriness of the bundle branches was measured by the extrastimulus technique in 16 patients with tachycardia-dependent bundle branch block and 10 patients with functional bundle branch block, both after basic trains of 8 atrial-paced impulses at different cycle lengths and during a 10-min period of continuous overdrive pacing.

RESULTS

The baseline refractory period in the bundle branches of patients with functional bundle branch block measured 430 +/- 32 ms (mean +/- SD) and shortened to 368 +/- 30 ms at the shortest cycle length. The maximal effect was reached within the 1st min of overdrive pacing. The baseline refractory period of the bundle branches was significantly longer in patients with tachycardia-dependent bundle branch block (611 +/- 184 ms) and demonstrated a cumulative overdrive prolongation in 15 (83%) of 18 studies with typical manifestations of fatigue. In two other studies, this occurred only after ajmaline administration.

CONCLUSIONS

A rate- and time-dependent prolongation of refractoriness frequently occurs in diseased human bundle branches. When absent, this response may be induced under the effects of sodium channel blockers. This would suggest that an abnormality in the recovery from inactivation of the sodium channel might underlie the early stages of bundle branch disease.

Verifying the reliability of interchanging casts between Hanau Modular articulators

PURPOSE

The purpose of this study was to test the Hanau Modular Articulator system with programmed fossae to determine its interchangeability.

MATERIALS AND METHODS

Eight Hanau Modular Articulators were tested using the same measuring system as previously developed in a similar investigation on a different instrument.

RESULTS

It was determined that the Hanau Modular System with programmed fossae did possess accuracy when a measuring device was transferred between the eight articulators tested.

CONCLUSIONS

Laboratory procedures for multiple restorations can be accomplished with accuracy when master casts and mountings are transferred between Hanau Modular Articulators.

Comparison of the physical properties of two types of polydimethyl siloxane for fabrication of facial prostheses

The in vitro physical properties of two types of polydimethyl siloxane, MDX 4-4210 and a new material A-2186, were compared. The properties that were investigated in this study were tensile strength, elongation, tear strength, and surface hardness. The properties tested were selected because of their clinical significance for fabricating a facial prosthesis. According to the results obtained in this investigation, the new material, A-2186, had greater tear resistance, tensile strength, and a larger percentage of elongation. A-2186 material, also proved to be softer at the surface than the MDX 4-4210. This combination of physical properties makes this material, A-2186, a better choice than the traditional MDX 4-4210 for the fabrication of facial prostheses.

Superoxide anion and hydrogen peroxide metabolism in soybean embryonic axes during germination

The total rate of mitochondrial O2- production in the presence of NADH as substrate increased from 200 to 1340 pmol/min per axis between 2 and 30 h of imbibition. The activities of the enzymes involved in hydroperoxide metabolism, e.g., superoxide dismutase, catalase, peroxidase and glutathione and ascorbate peroxidases, markedly changed during the germination of soybean embryonic axes. Superoxide dismutase was the enzymatic activity affected the most during the initial stages of germination. Intracellular O2- steady-state concentration, calculated from the rate of O2- production and superoxide dismutase activity, showed a 2-fold increase from 2 x 10(-8) M to 4 x 10(-8) M in germination phase I, declined in phase II to 2 x 10(-8) M and remained constant over the rest of the incubation period. The reaction of H2O2 and luminol catalyzed by Co2+ was utilized to measure H2O2 diffused out of the soybean axes after 5 to 10 min of incubation. The catalase-sensitive luminol emission of diffusates prepared from axes previously imbibed from 2 to 30 h corresponded to a H2O2 intracellular steady-state concentration in the range of 0.3 to 0.9 microM. The activity of metal-containing antioxidant enzymes was determined in the extracellular fluid. Cell wall peroxidase activity increased from 10 to 300 mumol/min per mg protein and appears as a potentially important pathway for H2O2 utilization. Hydrogen peroxide metabolism in soybean embryonic axes during early inhibition appears to have the following main features: (a) mitochondrial membranes are the most important source of cytosolic O2- and H2O2; (b) H2O2 is regulated at a steady-state concentration of 0.3-0.9 microM; (c) catalase is the main enzyme in terms of H2O2 utilization; (d) H2O2 exo-diffusion is quantitatively important destiny of intracellular H2O2; and (e) extracellular peroxidase located at the cell wall affords an enzymatic system able to use diffused H2O2.

Positional accuracy of four die tray systems

This study evaluated the positional accuracy of dies with four die tray systems. The die trays were: (1) Accu*trac Precision die system, (2) Model-Tray system, (3) Sterdo Split model tray, and (4) Tricodent One*Cast die tray system. Positional change of the dies was measured by using an Olympus binocular scanning tunneling microscope (STM). Positional change of the dies was the difference between preremoval and postremoval die position. Results show that all four die tray systems are not significantly different in most measurement categories, although the Model-Tray system was significantly different from the other die tray systems in one measurement category.

Verifying the reliability of interchanging casts with semiadjustable articulators

Interchangeability of a semiadjustable articulator could be of significant convenience and economic benefit to the restorative dentist. The manufacturer of the Whip-Mix Model 2240 articulator claims such interchangeability. This study evaluated the accuracy of the cross-mounting capability of eight such articulators, then compared the measured results with those obtained from eight semiadjustable instruments for which the manufacturer makes no such promise of interchangeability. It was determined that the Model 2240 articular did possess accuracy when a measuring device was transferred between the eight materials tested.

Recovery of erythrocyte Na(+)-K(+)-Cl- cotransport activity by enalapril

We studied total exchangeable sodium, ion transport activity at maximal rate, and erythrocyte Na+ content in response to angiotensin converting enzyme inhibition in mild-to-moderate essential hypertensive patients with normal renal function. Twenty-five patients (mean age 56 years, range 40-62 years) who had abnormal red blood cell Na(+)-K(+)-Cl- cotransport or red blood cell Li(+)-Na+ countertransport were treated with either enalapril (20 mg daily) or hydrochlorothiazide (50 mg daily) during a 30-day period. During the period of enalapril treatment, Na(+)-K+ pump and Na(+)-K(+)-Cl- cotransport increased significantly from 4,282 +/- 255 to 5,236 +/- 325 mumol/l red blood cell/hr (p less than 0.01) and 166 +/- 21 to 220 +/- 24 mumol/l red blood cell/hr (p less than 0.05), respectively. Mean intracellular Na+ content in erythrocytes decreased from 11.4 +/- 0.40 to 10.0 +/- 0.33 mmol/l (p less than 0.01) and exchangeable Na+ from 39.8 +/- 0.6 mmol/kg to 35.6 +/- 0.6 mmol/kg (p less than 0.001). Sodium reduction correlated with the recovery of Na(+)-K(+)-Cl- cotransport activity (r = -0.65, p less than 0.01). During treatment, systolic and diastolic blood pressures were reduced significantly (p less than 0.01). In 12 patients treated with hydrochlorothiazide, Na(+)-K(+)-Cl- cotransport, Na(+)-K+ pump, Na(+)-Li+ countertransport, and Na+ permeability did not change significantly while Na+ content decreased from 11.7 +/- 0.3 to 10.3 +/- 0.2 mmol/l (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Renal sodium handling abnormalities in hypertensive and normotensive patients with a family history of hypertension

We measured the effective renal plasma flow, the glomerular filtration rate and the fractional excretion of sodium under low and high sodium intakes in the normotensive offspring of hypertensives and in essential hypertensive patients. During the high sodium intake, 57% of the offspring and 42% of the hypertensive patients showed an increase in effective renal plasma flow and fractional excretion of sodium. In the remaining hypertensives, enalapril improved the renal haemodynamic and sodium-handling responses. Enalapril also reduced the blood pressure in all hypertensives, whether they showed a normal or an abnormal response to a high sodium intake. In the hypertensive patients with an abnormal response to a high sodium intake, the intra-erythrocyte sodium content was higher than in the normal responders. Thus, abnormal renal haemodynamic and sodium-handling responses to a high sodium intake were observed in 50% of the hypertensive patients and the offspring. The high intra-erythrocyte sodium content observed in the hypertensive patients suggests that extrarenal alterations in sodium handling were present.

Effect of stress conditions on Escherichia coli outer and inner membranes, separated by Sephacryl S-500 chromatography

A chromatographic method for the separation of outer and inner membranes of Escherichia coli is described. This method is much faster than the generally used equilibrium centrifugation and has a greater versatility in the volumes that can be treated. Both techniques are used to examine the effects of different stress conditions on the E. coli membrane. The obtained results illustrate the equivalence of both methods.

Role of cardiopulmonary mechanoreceptors in the postural regulation of renin

To change the stretch on cardiopulmonary mechanoreceptors, large shifts of blood in the capacity space were elicited by tilting and by exerting positive lower body pressure in the tilted position. Twelve volunteers underwent invasive hemodynamic studies and in 10 other subjects cardiac size was determined by radionuclide cardiography. In all 22 subjects tilting caused the expected increase of renin, which was abolished by lower body compression. Decompression caused renin to increase again. Right atrial pressure in invasive studies and end-systolic and end-diastolic counts in noninvasive studies showed a significant and strong negative correlation with renin and norepinephrine levels. Thus, the degree of stretch of the cardiopulmonary mechanoreceptors is a major determinant of reflex regulation of renin release in humans.

Spontaneous Chemiluminescence of Soybean Embryonic Axes during Imbibition

Isolated soybean (Glycine max L. var Hood) embryonic axes have a spontaneous chemiluminescence (about 150 counts per minute per embryo) that increases showing two phases, upon water imbibition. The first photoemission burst was measured between 0 and 7 hours of imbibition with a maximum of about 350 counts per minute per embryo after 2 hours. The second photoemission phase, between 7 and 30 hours, increased from about 220 to 520 counts per minute per embryo. Both chemiluminescence phases were inhibited by infused butylated hydroxyanisole while only the second phase was inhibited by infused salicylhydroxamic acid. On the basis of the sensitivity of the lipoxygenase reaction to both inhibitors (about 90%), the first burst is tentatively assigned to oxy-radicals mobilized upon water uptake by the embryonic axes, and the second phase is tentatively identified as due to lipoxygenase activity. The in vivo lipoxygenase activity of the embryonic axes was estimated by both the fraction of total oxygen uptake that was inhibited by butylated hydroxyanisole and by the fraction of photoemission that was inhibited by butylated hydroxyanisole and by salicylhydroxamic acid. Both approaches indicated marked increases (5-fold and 12-fold, respectively) of lipoxygenase activity between 2 and 30 hours of imbibition. The measured chemiluminescence per O(2) uptake ratio (the experimental quantum yield) for the lipoxygenase reaction (3.3 x 10(-14) counts per O(2) molecule) was used to estimate the O(2) uptake due to lipoxygenase activity from the photoemission of the embryonic axes after 30 hours of imbibition. The value (0.54 microliters per minute per axis) was close to the butylated hydroxyanisole-sensitive O(2) uptake (1.2 microliters O(2) per minute per axis) of the same embryonic axes. Chemiluminescence may afford a noninvasive assay for lipoxygenase activity in intact plant tissues.

Effects of Light Quality on Tiller Production in Lolium spp

Variations in phytochrome status in grasses were provoked by end of day red and far-red treatments and above canopy irradiations. Lolium perenne L. and Lolium multiflorum Lam. plants developed more tillers when illuminated with higher red/far-red ratios. These results show that branching of grasses is controlled by phytochrome activity in a way similar to that in dicotyledon plants.

Effects of water stress on the chlorophyll content, nitrogen level and photosynthesis of leaves of two maize genotypes

The dynamics of leaf chlorophyll level, nitrogen content, photosynthesis and stomatal conductance were followed in detail in two cultivars of maize (Zea mays) during a short period of water stress, applied at tasseling, and during the subsequent recovery phase. Plants used in the experiment were grown in sand-nutrient solution culture under field weather conditions. Water stress reduced chlorophyll levels, stomatal conductance and photosynthesis, but the nitrogen content of the leaves was not affected. It is concluded that the stress-induced loss of chlorophyll is not mediated by a lack of nitrogen. Considerable differences were observed between genotypes in the rate of post-stress recovery of chlorophyll level. Recovery, upon rewatering, of stomatal conductance and photosynthesis preceded that of chlorophyll level. Losses of up to 40% of leaf chlorophyll content were insufficient to affect rates of photosynthesis measured at mid-day.

Primitive earth synthesis of nicotinic acid derivatives

Nicotinonitrile, 2-cyanopyridine, and 4-cyanopyridine can be synthesized under primitive earth conditions by the action of electric discharges on ethylene and ammonia. The electric discharge first synthesizes pyridine and hydrogen cyanide, which react in the discharge to form the cyanopyridines. Nicotinonitrile would have hydrolyzed in the primitive ocean to nicotinamide and nicotinic acid.

Prebiotic synthesis of propiolaldehyde and nicotinamide

We have identified propiololdehyde as a product of the action of an electric discharge on mixtures of methane and water or methane, nitrogen, and water. The aldehyde reacts with cyanoacetaldehyde and ammonia (other "prebiological molecules") to yield nicotinonitrile. This substance can be hydrolyzed to nicotinamide and nicotinic acid.

Cyanoacetylene in prebiotic synthesis

Cyanoacetylene is a major nitrogen-containing product of the action of an electric discharge on a mixture of methane and nitrogen. It reacts with simple inorganic substances in aqueous solution to give products including asparticacid, asparagine, and cytosine.