Association between Citrus Consumption and Melanoma Risk in the NIH-AARP Diet and Health Study

It has been hypothesized that consumption of citrus, a group of foods particularly rich in a class of photoactive compounds known as furocoumarins, may increase the risk of malignant melanoma. However, this hypothesis has not been rigorously studied in a general sample of US men and women. This study examined the relationship between citrus intake and melanoma risk in subjects of the NIH-AARP Diet and Health Study. Among 388,467 adults, 3,894 melanoma cases were identified during a median follow-up of 15.5 years. After adjustment for relevant potential confounders, total citrus consumption was not significantly associated with melanoma risk in this cohort. Among those with higher estimated exposure to ultraviolet radiation, and among those aged 60+ years at baseline, there were significant trends toward increased melanoma risk associated with whole citrus fruit consumption (P trends = 0.01 and 0.02, respectively), but the hazard ratios of the top consumers (2+ cups per week) vs. nonconsumers were nonsignificant. Further research is needed to explore associations of citrus with melanoma risk among older adults and those with high sun exposure.

Identification and Quantification of Estrogenic Chemicals in Coffee Prepared from Capsules Using Ultra-Performance Liquid Chromatography with Tandem Mass Spectrometry

Objectives

Estrogenic chemicals (ECs) are harmful compounds that can leach from plastic, particularly when under high temperature or pressure. Capsule coffee, coffee brewed from a single-serve coffee machine using a pre-packed plastic capsule, is becoming popular but there are concerns that it may increase exposure to ECs. Therefore, the objective of this study was to identify and quantify the ECs in capsule coffee extracts and compare them to the ECs present in coffee extracts prepared using a method devoid of plastic.

Methods

Twenty-two top-selling varieties of plastic capsule coffee from 4 popular brands were brewed and 15 equivalent varieties of whole bean and ground coffee were brewed using a stainless-steel French press and used as controls. ECs were then extracted from the capsule samples and controls with liquid-liquid extraction. The ultra-performance liquid chromatography with tandem mass spectrometry analytical method was used to identify and quantify ECs in coffee extracts after testing its validity.

Results

Benzophenone was the most frequently detected EC among the 22 capsule coffee samples, evident in six samples, followed by bisphenol A (four), dibutyl phthalate (three), 4-nonylphenol (three) and bisphenol F (two). Di(2-ethylhexyl) phthalate, caprolactam, bisphenol S and dimethyl terephthalate were either not detected or detected in quantities below the method detection limit. In seven instances the concentration of ECs in capsule coffees was greater than that of coffee prepared from the French press while in five instances the opposite trend was observed. The total exposure to ECs from either capsule coffee or coffee prepared from the French press was well below that of safety guidelines.

Conclusions

These results indicate that consuming plastic capsule coffee likely increases exposure to ECs compared to coffee brewed without plastic. Future studies are needed to evaluate the estrogenic activities of capsule coffee in vitro and determine whether EC content is a valid predictor of estrogenic activity.

Funding Sources

This study was supported by the National Institutes of Health.

Determination of the Estrogenic Activity of Coffee Extract Solutions Prepared from Capsule Coffee Using the BG1Luc4E2 Assay

Objectives

Estrogenic chemicals (ECs) possess estrogenic activity (EA) which can have harmful effects on the reproductive system. Coffee is known to have estrogenic potency due to its natural phytoestrogens, but coffee prepared from plastic capsules (capsule coffee) may increase exposure to ECs and consequently increase EA, potentially increasing risk to reproductive health. The objective of this study was to determine the EA of capsule coffee extract solutions in vitro.

Methods

Six varieties of capsule coffee and two varieties of coffee prepared from whole beans using a stainless-steel French press were first brewed then concentrated and extracted. The BG1Luc4E2 assay was then conducted to determine the EA of the coffee extracts. The normalized EA (% RME2) of the coffee extracts was determined as the relative estrogenic potency compared to the maximum normalized EA of the positive control 17β-estradiol (set to 100 % RME2). EA was determined if at least one data point on the concentration-response curve was above 15% RME2 and confirmed via inhibition with the estrogen receptor antagonist ICI 182,780. The correlation between the EA estimated by the BG1Luc4E2 assay and the estrogenic potential (EEQ) was determined with Spearman's rank correlation coefficient.

Results

All eight coffee extract solutions tested positive for EA and results were confirmed by their complete inhibition with ICI. The level of EA for the six capsule coffee extracts ranged from 48 to 56 % RME2, while the level of EA for the two coffee varieties prepared from whole beans were 40 and 42 % RME2. There was a significant correlation between EA and EEQ was (ρ = 0.8857, P = 0.0333).

Conclusions

These results indicate that the EAs of capsule coffees were higher than that of coffee prepared from a plastic-free method and that the EA measured in an in vitro model was correlated with the calculated estrogenic potential of the coffee extract's EC contents. Future studies are warranted in in vivo models as well as in humans as tests of estrogenic potency in vitro do not necessarily predict the effects in living organisms.

Funding Sources

This study was supported by the National Institutes of Health.

Relative Validity of Dietary Total Antioxidant Capacity for Predicting All-Cause Mortality in Comparison to Diet Quality Indexes in US Adults

Objectives

Dietary total antioxidant capacity (TAC) is a useful tool for assessing total antioxidant power in the diet, and high dietary TAC has been reported to be associated with lower oxidative stress and risk of chronic diseases. While traditionally diet quality index scores (DQIS) have been used to predict health outcomes, dietary TAC may also be a novel and valid predictor. Therefore, this study aimed to evaluate the associations between both dietary TAC and DQIS and all-cause mortality.

Methods

Based on the National Health and Nutrition Examination Survey (NHANES) III (1998–1994) and 1999–2006, a total of 23,797 adults aged 30 years or older who were followed-up until 2015 were included. Dietary TAC and DQIS including the Healthy Eating Index-2015 (HEI-2015), Alternative Health Eating Index-2010 (AHEI-2010), alternate Mediterranean Diet (aMED), and Dietary Approaches to Stop Hypertension (DASH) were calculated using a 1-day 24-h dietary recall. Hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality by quintiles of dietary TAC and DQIS were estimated using Cox proportional hazards models.

Results

Dietary TAC and DQIS similarly differed by sociodemographic characteristics including age, gender, race/ethnicity, education, and income and lifestyle behaviors such as physical activity and smoking among US adults (P < 0.0001 for all). After adjusting for confounders, US adults in the highest quintiles of DQIS had lower rates of all-cause mortality compared to those in the lowest quintiles (HEI-2015 HR: 0.86, 95% CI: 0.76–0.97; AHEI-2010 HR: 0.83, 95% CI: 0.73–0.93; aMED HR: 0.78, 95% CI: 0.68–0.89; DASH HR: 0.78, 95% CI: 0.69–0.89). Similarly, those in the highest quintile of dietary TAC also had a lower rate of all-cause mortality than those in the lowest quintile (HR: 0.89, 95% CI: 0.79–0.99).

Conclusions

These findings indicate that both DQIS and dietary TAC were inversely associated with all-cause mortality and that dietary TAC predicts overall mortality in US adults. Further studies should expand this investigation to assess disease-specific mortality among subpopulations defined by gender, race/ethnicity, and socioeconomic status.

Funding Sources

This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education.

Flavonoid Intake Varies by Racial/Ethnic Groups Within Sociodemographic Categories

Objectives

Diets rich in flavonoids can reduce the risk of developing chronic diseases through their antioxidant and anti-inflammatory properties. While differences in flavonoid intake by race/ethnicity have been previously described, differences between race/ethnicity within categories sociodemographic characteristics have not been fully assessed. Therefore, the objective of this study was to estimate flavonoid intake and evaluate the disparities by race/ethnicity within categories of sociodemographic characteristics in US adults.

Methods

A total of 15,775 US adults aged 20 years and older in NHANES 2007–2014 were included in this cross-sectional study. Flavonoid intake was calculated by linking food consumption data from a 24-hour diet recall to a flavonoid database which has been expanded on by our research group using the USDA Databases for the Flavonoid (Release 3.3), and Isoflavone (Release 2.1) in addition to the USDA's Expanded Flavonoid Database for the Assessment of Dietary Intakes (Release 1.1). Mean (SE) flavonoid intakes by sociodemographic categories were compared with one-way ANOVA.

Results

Among US adults, mean (SE) total flavonoid intake was 227.6 (8.0) mg/day, and total flavonoid intake was highest in 40–59 year olds, non-Hispanic whites, those with a poverty-income ratio (PIR) ≥1.85, those with a college education or above, and those married or living with a partner. In most sociodemographic categories, Hispanics consistently had the lowest total flavonoid intakes compared to other races/ethnicities. Among Hispanic subgroups, total flavonoid intake was lowest in men, 20–39 years olds, PIR < 1.3, less than high school education, and single marital status (men only). Ethnic disparities in flavonoid intake were more pronounced between certain sociodemographic subcategories including men, 40–59 year olds, PIR < 1.3, less than high school education, and married marital status (men only).

Conclusions

These findings indicate that there are significant racial differences in flavonoid intake. Notably, Hispanics tended to have the lowest intake. Certain sociodemographic populations such as males, low income or low educated may be at an increased risk of flavonoid under-consumption.

Funding Sources

This research received no external funding.

Orange Juice Consumption Is Not Associated with Excess Weight Gain in a Large Prospective Cohort of US Children and Adolescents

Objectives

Given the conflicting evidence regarding fruit juice consumption and childhood obesity, we sought to evaluate associations between 100% orange juice (OJ) consumption and changes in anthropometric parameters in a large prospective cohort of US children and adolescents.

Methods

Participants from the Growing Up Today Study II (n = 7301) completed a baseline questionnaire in 2004 and follow-up questionnaires in 2006 and 2008. Data from these questionnaires were then used to assess mean 2-year changes in anthropometric characteristics in relation to OJ consumption. Changes in body mass index (BMI) percentile and height-for-age z-score (HAZ) were computed across OJ consumption categories using mixed linear regression modeling.

Results

Girls’ 2-year mean (SD) change in BMI percentile was not associated with OJ consumption after full adjustment: −0.44 (0.36) for OJ non-consumers, 0.20 (0.41) for 1–3 glasses/month, −0.04 (0.34) for 1–6 glasses/week, and −0.77 (0.62) for ≥1 glass/day (P-trend = 0.49). Meanwhile, girls’ 2-year mean (SD) change in HAZ was positively associated with OJ consumption: 0.03 (0.01) for non-consumers, 0.03 (0.02) for 1–3 glasses/month, 0.06 (0.01) for 1–6 glasses/week, and 0.09 (0.02) for ≥1 glass/day after full adjustment (P-trend = 0.02). There were no significant associations in boys.

Conclusions

These results indicate that OJ consumption was not associated with BMI percentile but was positively associated with HAZ change in girls, suggesting that OJ consumption is unlikely to contribute towards obesity.

Funding Sources

This study was supported by the Florida Department of Citrus, an executive agency of the state of Florida.

Impacts of Aging and Blackcurrant Supplementation on the Gut Microbiome Profile of Female Mice (P20-031-19)

Objectives

Blackcurrant, an anthocyanin-rich berry, has multiple health benefits. The purpose of this study was to examine the impacts of blackcurrant supplementation and aging on gut bacterial communities in female mice.

Methods

Three-month and 18-month old female mice were provided standard chow diets with or without anthocyanin-rich blackcurrant extract (BC) (1% w/w) for four months. Upon study completion, fecal samples were collected directly from the animals’ colons. Microbiome DNA was extracted from the fecal samples and the V3-V4 regions of their 16S rRNA gene were amplified and sequenced using

Results

Taxonomic analysis showed a significantly decrease in alpha diversity in aged female mice, compared to young counterparts. BC consumption did not alter the alpha diversity in either young or aged mice compared to control diets. For beta diversity, we observed the clustering was associated with age but not diet. The phylogenic abundance analysis showed that the relative abundance of several phyla, including Firmicutes, Bacteroidetes, Cyanobacteria, Proteobacteria, and Tenericutes was higher in aged compared to young mice. Among them, the abundance of Firmicutes was downregulated by BC in the young but not the aged mice. The abundance of Bacteroidetes was increased by BC in both the young and the aged groups. Noticeably, Verrucomicrobia was the only phylum whose relative abundance was upregulated in the aged female mice compared to the young mice. Meanwhile, its relative abundance in the aged group was suppressed by BC. Interestingly, Desulfovibrio, which is the most representative sulfate-reducing genus, was detectable only in young female mice, and BC increased its relative abundance.

Conclusions

Our results characterized the gut microbiome compositions in young and aged female mice, and indicated that the gut microbiome of young and aged female mice responded differently to four month BC administration. Through additional research, the microbial alterations observed in this study should be further investigated to inform our understanding of the effect of BC on the gut microbiome, the possible health benefits related to these changes, and the differing effects of BC supplementation across populations.

Funding Sources

This study was supported by the USDA NIFA Seed Grant (#2016-67018-24492) and the University of Connecticut Foundation Esperance Funds to Dr. Ock K. Chun. We thank the National Institute on Aging for providing aged mice for the project and Just the Berries Ltd. for providing the blackcurrant extract.

Association of Urinary Cadmium with Cancer Mortality Is Influenced by Zinc Intake in Follow-up Study of NHANES 1988–1994 and 1999–2004 (P18-026-19)

Objectives

Exposure to cadmium (Cd), a toxic heavy metal, increases risk of numerous chronic diseases and overall mortality. However, little work has been conducted to examine the effect of Zn intake on the association between Cd burden and mortality. The aim of this study was to examine whether the association between urinary Cd concentration and all-cause and disease specific mortality differs by Zn intake level among a representative sample of the US adult population.

Methods

A total of 15,642 US adults aged 30 years and older in the National Health and Nutrition Examination Survey 1988–1994 and 1999–2004 were followed up through December 31, 2011. Participants’ Zn intake was assessed through 24-hour dietary recalls. The main outcomes included mortality from cardiovascular disease (CVD), cancer, and all causes. Using Cox proportional hazards models, hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated for quartiles of urinary Cd, quartiles of dietary Zn, and for quartiles of urinary Cd stratified by level of dietary Zn.

Results

Of 5367 total deaths that occurred over a mean follow-up of 15 years, 1194 were attributed to cancer and 1677 were attributed to CVD. After adjustment for potential confounders, positive relationships were observed between urinary Cd and all-cause mortality (HR for highest vs. lowest quartile (Q4 vs. Q1): 1.38; 95% CI: 1.14–1.68; P-trend < 0.0001) and cancer mortality (HR for Q4 vs. Q1: 1.54; 95% CI: 1.05–2.27; P-trend < 0.005), but not CVD mortality (HR for Q4 vs. Q1: 1.22; 95% CI: 0.95–1.57; P-trend = 0.0502). Negative associations were observed between dietary Zn and all-cause mortality (HR for Q4 vs. Q1: 0.88; 95% CI: 0.75–1.02; P-trend < 0.05) and cancer mortality (HR for Q4 vs. Q1: 0.82; 95% CI: 0.65–1.03, P-trend < 0.05). Among the lowest tertile of Zn consumers, there was a clear positive association between urinary Cd and cancer mortality (HR for Q4 vs. Q1: 1.79; 95% CI: 1.07–3.01), however, among the highest Zn consumers, this association was somewhat diminished (HR for Q4 vs. Q1: 1.66; 95% CI: 0.80–3.41).

Conclusions

These findings support existing evidence that Cd burden is associated with greater mortality, and also demonstrate that greater Zn consumption is associated with reduced risk of cancer death related to Cd.

Funding Sources

This study received no financial support.

Associations Between OJ Consumption and Dietary and Lifestyle Characteristics and Anthropometric Parameters in a Cross-Sectional Study of U.S. Children from GUTS I and II (P18-007-19)

Objectives

Concerns about orange juice's (OJ) high sugar content have contributed to reduced consumption in the U.S. The objective of this study is to evaluate the association between 100% OJ consumption and anthropometric indicators and health-related behaviors in adolescents.

Methods

Data from the Growing Up Today Study (GUTS), an ongoing prospective cohort study of adolescents from across the U.S. which began its first cohort (GUTS I) in 1996 and its second cohort (GUTS II) in 2004, were analyzed.

Results

In a cross-sectional examination of baseline data (n = 26,503), there was a significant trend toward lower prevalence of overweight and obesity among children who reported consuming more OJ among boys of GUTS I and girls and boys of GUTS II. Across each cohort and gender, OJ intake was positively associated with height, height-for-age z-score, total energy intake, consumption of fruits and non-starchy vegetables, consumption of foods of low nutritional quality, and physical activity, while screen time was negatively associated with OJ consumption. In boys across both cohorts, the adjusted odds ratios (OR & 95% CI) of being classified as overweight or obese were 0.90 (0.76, 1.08) for 1–3 glasses of OJ per month, 0.94 (0.80, 1.11) for 1–6 glasses per week, 1.01 (0.82, 1.24) for 1 glass per day, and 1.13 (0.87, 1.48) for >1 glass per day (P-trend = 0.3251), using non-consumers as a reference. In girls, the ORs were 0.87 (0.74, 1.30) for 1–3 glasses per month, 0.97 (0.83, 1.14) for 1–6 glasses per week, 1.04 (0.84, 1.28) for 1 glass per day, and 0.68 (0.52, 0.89) for >1 glass per day (P-trend = 0.4345).

Conclusions

The results indicate that children consuming more OJ tended to practice healthier dietary and lifestyle habits than OJ non-consumers. Additionally, a lower prevalence of overweight and obesity was observed among children who consumed more OJ. In adjusted analyses controlling for other obesity risk factors, OJ consumption was not associated with higher odds of being overweight or obese.

Funding Sources

The Florida Department of Citrus, an executive agency of the state of Florida, provided funding for this project.

Free fatty acid receptor 1 agonist, MR1704, lowers blood glucose levels in rats unresponsive to the sulfonylurea, glibenclamide

Preclinical Research & Development MR1704 is a selective G protein-coupled receptor 40/free fatty acid receptor 1 agonist, which exhibited favorable pharmacokinetic profiles and glucose-lowering effects in animal models. We studied the effects of MR1704 in a sulfonylurea-desensitized Sprague-Dawley rat model and evaluated the risk of pancreatic β-cell exhaustion compared to that of glibenclamide in Zucker fatty rats. Rats fed ad libitum a diet containing 0.03% glibenclamide exhibited lower non-fasting blood glucose levels compared to those in rats fed a control diet during the first 6 days. However, the response to glibenclamide disappeared on day 9. In a rat oral glucose tolerance test (OGTT), MR1704 reduced the plasma glucose excursion, whereas glibenclamide did not show this effect. In Zucker fatty rats, oral administration of MR1704 reduced glucose excursion during the OGTT, and the effects of MR1704 were maintained after 2-week treatment. In contrast, the glucose-lowering effects of glibenclamide were diminished, and glucose tolerance was aggravated after 2-week treatment. These results indicated that MR1704 provided more sustainable effects compared to those of the sulfonylurea, glibenclamide suggesting that MR1704 may be an attractive therapeutic option for diabetic patients who are unresponsive to sulfonylurea treatment.

A novel free fatty acid receptor 1 (GPR40/FFAR1) agonist, MR1704, enhances glucose-dependent insulin secretion and improves glucose homeostasis in rats

Activation of G protein‐coupled receptor 40/Free fatty acid receptor 1 (GPR40/FFAR1), which is highly expressed in pancreatic β cells, is considered an important pharmacologic target for the treatment of type 2 diabetes mellitus. The aim of this study was to determine the effect of MR1704, a novel GPR40/FFAR1 agonist, on glucose homeostasis in rats. MR1704 is a highly potent and selective, orally bioavailable agonist with similar in vitro potencies among humans, mice, and rats. Treatment of rat islets with MR1704 increased glucose‐dependent insulin secretion. Augmentation of glucose‐dependent insulin secretion was abolished by adding a GPR40/FFAR1 antagonist. In mouse, insulinoma MIN6 cells, palmitic acid induced the activity of caspase 3/7 after a 72‐h exposure, while pharmacologically active concentrations of MR1704 did not. In an oral glucose tolerance test in normal Sprague‐Dawley rats, orally administered MR1704 (1–10 mg·kg⁻¹) reduced plasma glucose excursion and enhanced insulin secretion, but MR1704 did not induce hypoglycemia, even at 300 mg·kg⁻¹, in fasted Sprague‐Dawley rats. In addition, orally administered MR1704 reduced plasma glucose excursion and enhanced insulin secretion in diabetic Goto‐Kakizaki rats. Oral administration of MR1704 once daily to Goto‐Kakizaki rats reduced their blood glucose levels during a 5‐week treatment period without reducing pancreatic insulin content; as a result, hemoglobin A1C levels significantly decreased. These results suggest that MR1704 improves glucose homeostasis through glucose‐dependent insulin secretion with a low risk of hypoglycemia and pancreatic toxicity. MR1704 shows promise as a new, glucose‐lowering drug to treat type 2 diabetes mellitus.

Pharmacological inhibition of diacylglycerol acyltransferase 1 reduces body weight and modulates gut peptide release--potential insight into mechanism of action

OBJECTIVE

Investigation was conducted to understand the mechanism of action of diacylglycerol acyltransferase 1 (DGAT1) using small molecules DGAT1 inhibitors, compounds K and L.

DESIGN AND METHODS

Biochemical and stable-label tracer approaches were applied to interrogate the functional activities of compounds K and L on TG synthesis and changes of carbon flow. Energy homeostasis and gut peptide release upon DGAT1 inhibition was conducted in mouse and dog models.

RESULTS

Compounds K and L, dose-dependently inhibits post-prandial TG excursion in mouse and dog models. Weight loss studies in WT and Dgat1(-/-) mice, confirmed that the effects of compound K on body weight loss is mechanism-based. Compounds K and L altered incretin peptide release following oral fat challenge. Immunohistochemical studies with intestinal tissues demonstrate lack of detectable DGAT1 immunoreactivity in enteroendocrine cells. Furthermore, (13) C-fatty acid tracing studies indicate that compound K inhibition of DGAT1 increased the production of phosphatidyl choline (PC).

CONCLUSION

Treatment with DGAT1 inhibitors improves lipid metabolism and body weight. DGAT1 inhibition leads to enhanced PC production via alternative carbon channeling. Immunohistological studies suggest that DGAT1 inhibitor's effects on plasma gut peptide levels are likely via an indirect mechanism. Overall these data indicate a translational potential towards the clinic.

Novel scaffold for cathepsin K inhibitors

Pyrrolopyrimidine, a novel scaffold, allows to adjust interactions within the S3 subsite of cathepsin K. The core intermediate 10 facilitated the P3 optimization and identified highly potent and selective cathepsin K inhibitors 11-20.

Synthesis and structure–activity relationship of RXR antagonists based on the diazepinylbenzoic acid structure

Synthesis and structure-activity relationship of RXR antagonists employing a diazepinylbenzoic acid scaffold are described. Of those antagonists, sulfonamide derivatives (6v and 6w) reveal a high antagonistic activity and good pharmacokinetic properties.

Synthesis and structure–activity relationship of novel RXR antagonists: Orally active anti-diabetic and anti-obesity agents

A series of diazepinylbenzoic acid derivatives were synthesized and tested in the inhibition assay of the transactivation of RXR. Oral treatment of cyano derivatives (16f) was found to show anti-diabetic and anti-obesity effects in KK-A(y) mice.

Effect of a novel bifunctional endothelin receptor antagonist, IRL 3630A, on guinea pig respiratory mechanics

This study characterized the in vitro pharmacological properties of a newly developed endothelin receptor antagonist, N-butanesulfonyl-[N-(3, 5-dimethylbenzoyl)-N-methyl-3-[4-(5-isoxazolyl)-phenyl]-(D)- alanyl]-( L)-valineamide sodium salt (IRL 3630A), and its in vivo effects on respiratory mechanics were determined. IRL 3630A showed highly balanced affinities to human endothelin ET(A) and ET(B) receptors, giving apparent K(i) values of 1.5 and 1.2 nM, respectively. This compound also potently antagonized the endothelin-1-induced intracellular Ca(2+) increases in both embryonic bovine tracheal (EBTr) cells expressing endothelin ET(A) receptors and human Girardi heart (hGH) cells expressing endothelin ET(B) receptors. In guinea pig isolated tracheas having both endothelin ET(A) and ET(B) receptors, IRL 3630A greatly inhibited endothelin-1-induced contraction (pA(2)=7.1), which was partially or scarcely suppressed by the endothelin ET(A) receptor antagonist cyclo[-(D)-Trp-(D)-Asp-(L)-Pro-(D)-Val-(L)-Leu-] (BQ-123) or the endothelin ET(B) receptor antagonist N-(3, 5-dimethylbenzoyl)-N-methyl-3-(4-phenyl)-(D)-phenylalanyl-(L)-t ryptop han (IRL 2500), respectively. Bolus i.v. injections of IRL 3630A administered into anaesthetized guinea pigs at 10 and 30 microg/kg inhibited endothelin-1 (1.3 microg/kg)-induced changes in respiratory resistance and compliance in a dose dependent manner, whereas both sodium 2-benzo[1, 3]dioxol-5-yl-4-(4-methoxy-phenyl)-4-oxo-3-(3,4, 5-trimethoxy-benzyl)-but-2-enoate (an endothelin ET(A) receptor antagonist: PD 156707) and IRL 2500 at doses of up to 30 microg/kg did not affect endothelin-1-induced changes in respiratory mechanics, reflecting the in vitro results. IRL 3630A is thus an effective bifunctional endothelin receptor antagonist, and will be useful in clarifying the role of endothelin in pulmonary diseases such as bronchial asthma.

[A case of pulmonary fat embolism and cardiac arrest after prosthetic replacement of the femoral stem]

We experienced a case of cardiac arrest which occurred after prosthetic replacement of the femoral stem. The patient died three hours and fifty minutes after the end of operation, following hypouresis, pulmonary edema and hypoxia. According to the autopsy, extensive and severe fat embolism was documented in the lung and kidney, and this is considered to be the cause of the death. When prosthetic replacement of the femoral head is performed, we have to keep in mind the danger of fat embolism.

Stereoselective synthesis of a novel and bifunctional endothelin antagonist, IRL 3630

IRL 3630 (3), a single enantiomer of IRL 3461 with more potency was identified. Coupling reaction of the racemic fragment (1) with the chiral (L)-valinesulfonamide (2) under a biphasic solvent system (CH2Cl2-H2O) successfully led to the predominant formation of the desired isomer (3) with concomitant isomerization of 1. IRL 3630, N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-+ ++isoxazolyl) -phenyl]-(D)-alanyl]-(L)-valineamide, is a highly potent and bifunctional (ETA + ETB) antagonist [Ki(ETA) = 1.5 nM, Ki(ETB) = 1.2 nM].

Discovery of IRL 3461: a novel and potent endothelin antagonist with balanced ETA/ETB affinity

IRL 3461, N-butanesulfonyl-[N-(3,5-dimethylbenzoyl)-N-methyl-3-[4-(5-+ ++isoxazolyl) -phenyl]-alanyl]-(L)-valineamide, a potent and bifunctional (ETA + ETB) [Ki(ETA) = 1.8 nM, Ki(ETB) = 1.2 nM] antagonist was discovered by structural modification of IRL 2500, an ETB selective antagonist. IRL 3461 was found to be stable on incubation with human, rat, mouse, and guinea pig plasmas.

Profiling of trans-azetidine-2,4-dicarboxylic acid at the human metabotropic glutamate receptors mGlu1b, -2, -4a and -5a

We have tested the two enantiomers of trans-azetidine-2,4-dicarboxylic acid, (2S,4S)-azetidine-2,4-dicarboxylic acid ((2S,4S)-ADA) and (2R,4R)-azetidine-2,4-dicarboxylic acid ((2R,4R)-ADA) for activity at the human metabotropic glutamate receptors mGlu1b, mGlu2, mGlu4a and mGlu5a expressed in mammalian cells. In Chinese hamster ovary (CHO) cells expressing human mGlu2 receptors, 500 microM (2S,4S)-ADA inhibited forskolin-stimulated cAMP accumulation by 33 +/- 3% while 100 microM (1S,3R)-1-Aminocyclopentane-1,3-dicarboxylic acid induced an inhibition by 66 +/- 5%. The (2R,4R)-ADA enantiomer was inactive at human mGlu2 receptors. In CHO cells expressing human mGlu4a receptors, 10 microM L-AP4 inhibited forskolin-stimulated cAMP levels by 37 +/- 4% whereas both ADA enantiomers of trans-azetidine-2,4-dicarboxylic acid (500 microM) had no such effect. In CHO cells expressing human mGlu1b receptors and L cells expressing human mGlu5a receptors, both enantiomers, applied at 500 microM or 1 mM, were ineffective in stimulating inositolmonophosphate accumulation and did not affect quisqualate-stimulated inositolmonophosphate accumulation. We conclude that (2S,4S)-azetidine-2,4-dicarboxylic acid is a weak human mGlu2 receptor agonist and that (2R,4R)-azetidine-2,4-dicarboxylic acid is inactive at human mGlu2 receptors. Trans-azetidine-2,4-dicarboxylic acid has no significant agonistic effect on human mGlu4a receptors and neither agonistic nor antagonistic effects on human mGlu1b and mGlu5a receptors.

Effect of prior administration of succinylcholine on duration of action of vecuronium during enflurane anaesthesia

The effects of succinylcholine, which was given to facilitate tracheal intubation on the duration of action of subsequently administered vecuronium bromide, were evaluated in 54 adult patients who underwent abdominal surgeries under enflurane anaesthesia. The electromyographic response to train-of-four ulnar nerve stimulation was measured. Twenty-seven patients received 1 mg.kg-1 of succinylcholine, followed by 0.15 mg.kg-1 of vecuronium when the electromyographic response recovered to 50% of control after succinylcholine-induced neuromuscular blockade. The other 27 patients served as the control group, receiving 0.15 mg.kg-1 of vecuronium without prior administration of succinylcholine. In both groups, administration of supplemental 0.04 mg.kg-1 of vecuronium was repeated whenever the electromyographic response recovered to 25% of control during surgical procedures. The duration of blockade induced by the initial 0.15 mg.kg-1 of vecuronium was 56.5 +/- 12.8 (mean +/- s.d.) min for the group with succinylcholine, and 58.5 +/- 21.5 min for the control group. In both groups, the average duration of four consecutive supplemental doses of vecuronium was approximately 35 min. No significant differences between groups were found in the duration of neuromuscular blockade induced by initial and supplemental doses of vecuronium.

[Prostaglandin E1 (PGE1) prevents the pressure responses to tracheal intubation in hypertensive patients]

Forty-five hypertensive patients for elective abdominal surgery were investigated regarding the effects of PGE1 on the cardiovascular responses to tracheal intubation. Administration of PGE1 at the dose of 0.10 or 0.20 micrograms.kg-1.min-1 for 10 minutes before tracheal intubation significantly reduced the blood pressure responses immediately after the intubation and 2 minutes later. The increases in heart rate were not altered with and without the administration of PGE1. So the increases in rate pressure products were markedly reduced with PGE1 compared with the control values. Plasma concentration of catecholamines was measured before and after tracheal intubation. Norepinephrine was elevated markedly immediately after the intubation and this change was not affected by the infusion of PGE1. These results demonstrate that PGE1 ameliorates the pressure responses by the release of norepinephrine and thus reduces the increases in rate pressure products immediately after tracheal intubation.