Molecular modification of anticholinergics as probes for muscarinic receptors. 2. Amino esters of alpha-methyltropic acid

As a continuation of our goals to study molecular probes for muscarinic cholinergic receptors, a series of 3-substituted 2-methyl-2-phenylpropanoates with the general structure of C6H5C(CH2X)(CH3)COOCH2CH2NEt2 where X = OH, OTs, F, Cl, Br, I, and OAc were prepared and their antispasmodic activities examined on isolated rat ileum preparations. Structure-activity relationship studies with these compounds provide further evidence suggesting that binding of an aromatic moiety in a specific location within the hydrophobic region of the receptor is important for anticholinergic potency. A nucleophilic displacement of chloride by "naked" fluoride under mild conditions is also reported.     

Modulation of the peritoneal clearance of liposomal cytosine arabinoside by blank liposomes

Summary Liposomes containing cytosine arabinoside (ara-C) release drug slowly and can be used to maintain a locally high concentration of ara-C in the peritoneal cavity for intracavitary chemotherapy. However, a significant amount of active drug does reach the systemic circulation and contributes to systemic toxicity. We have devised a novel method of decreasing toxicity and increasing intraperitoneal half-life by pretreatment with blank liposomes containing no active drug. This technique has resulted in prolongation of intraperitoneal half-life of the liposomal ara-C from 21 h to 165 h, enabling maintenance of a therapeutic drug concentration even at 11 days after initial injection. One hundred percent cures (60-day survival) were achieved with a single-dose therapy begun 1 day after i. p. implantation of 10⁶ L1210 leukemia cells.Supported in part by Public Health Service grants CA-01082, CA-35309, and CA 23100 from the National Cancer Institute, National Institute of Health, DHHS. This work was conducted in part by the Clayton Foundation for Research, California Division. Stephen B. Howell is a Clayton Foundation Investigator     

Studies on the development of enzyme linked immunosorbent assay (ELISA) for hepatitis B surface antigen(HBsAg) by monoclonal antibodies of different affinity constants

Mouse monoclonal antibodies to Hepatitis B surface antigen(HBsAg) were prepared and their functional capabilities tested by the method of solid phase enzyme linked immuno sorbent assay(ELISA). HBsAg binding studies indicated that one monoclonal antibody 6E-1-1 bound more HBsAg at a faster rate than the other monoclonal antibodies. Also, for the binding inhibition studies with the selected monoclonal antibody 6E-1-1, one monoclonal antibody 8D-3-6 didn’t exhibit binding inhibition for HBsAg. Then, a simultaneous ELISA method was developed for the immunodiagnosis of HBsAg. Different combinations of two monoclonal antibodies as solid phase and horseradish peroxidase(HRPO) labeled phase were studied. The combination of monoclonal antibody of higher affinity constant (6E-1-1) immobilized in a solid phase and monoclonal antibody of lower affinity constant (8D-3-6) as a HRPO labeled phase was more sensitive when two monoclonal antibodies of different affinity constants for HBsAg were prepared.     

Acute toxicity in the guinea pig and in vitro "dioxin-like" activity of the environmental contaminant 1,2,4,5,7,8-hexachloro (9H)xanthene

A number of sites in the state of Missouri have been contaminated with polychlorinated dibenzodioxins and dibenzofurans as a result of improper waste-oil application for dust control. In addition to these compounds, relatively high levels of 1,2,4,5,7,8-hexachloro(9H)xanthene (1,2,4,5,7,8-HCX), a by-product of hexachlorophene manufacture, were also detected. Unlike the dibenzodioxins and dibenzofurans, no animal toxicity data are available on the chlorinated xanthenes. In view of the potential importance of this novel class of environmental contaminants, studies were conducted to examine the acute oral toxicity in guinea pigs and in vitro "dioxin-like" activity of 1,2,4,5,7,8-HCX. Animals administered a single oral dose of 0.02, 0.1, 0.5 or 2.5 mg 1,2,4,5,7,8-HCX/kg in corn oil and sacrificed 42 d later exhibited no treatment-related pathology. Guinea pigs given 12.5 mg/kg displayed mild to moderate distension and histologically observable subserosal edema of the urinary bladder, in addition to mild fatty vacuolization of pancreatic acinar cells. The alterations were considered to be of minimal toxicological significance. No compound- or dose-related mortality, body weight loss, or organ weight changes were noted at any dose level. Results using an in vitro bioassay for "dioxin-like" activity confirmed preliminary data suggesting that 1,2,4,5,7,8-HCX is about 10(6) times less potent than 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in this assay system. These findings indicate that 1,2,4,5,7,8-HCX may represent a relatively low environmental hazard compared to 2,3,7,8-TCDD.     

Acetylcholinesterase and manometry in the diagnosis of the constipated child

We studied 309 constipated infants and children who underwent rectal manometry (n = 261) and/or punch rectal biopsy, in which acetylcholinesterase histochemistry (n = 124) was compared with routine histologic examination (n = 93) for diagnostic accuracy. A 99% diagnostic accuracy was achieved with acetylcholinesterase histochemistry compared with 61% accuracy with routine hematoxylin-eosin staining on punch rectal biopsy. We recommend screening cooperative, quiet patients with rectal manometry. Most patients with abnormal manometric studies or those on whom manometry cannot be performed should have superficial punch biopsy (except those ill infants who require urgent operative intervention). This plan of management provides the least invasive but the most accurate evaluation of the constipated child. Deep rectal biopsy can be avoided except in the very rare child with hypoganglionosis or "skip-area" aganglionosis, which can be detected by manometry.     

Effect of phenothiazine derivatives on the thermotropic phase transition of liposomal phospholipid membrane

The effect of phenothiazine derivatives on the thermotropic transition of liposomal lipid bilayer made of dipalmitoyl phosphatidylcholine and dipalmitoyl phosphatidic acid was investigated with differential scanning calorimetry. The thermograms of the liposomal bilayer incorporated with levomepromazine, chlorpromazine, prochlorperazine, perphenazine and fluphenazine were obtained and the size of cooperative unit of the transition were calculated from the ratio of the van’t Hoff enthalpy change to the calculated enthalpy change of the transition. The results showed that incorporation of phenothiazine derivatives into the liposomal bilayer reduced the transition temperature at which the transition from solid state to liquid-crystalline state occurs, and broadened the thermogram peaks. Phenothiazine derivatives also significantly reduced the size of cooperative unit of the transition. The effect of the drugs was proportional to the concentration of the drug in the bilayer. This means that phenothiazine derivatives might have significant fluidizing effects on the biomembrane. The sizes of cooperative unit were successfully correlated with pharmacological activities of the drugs and the surface pressure increases of lipid monolayer by these drugs. These correlations might be ascribed to a possible hydrophobic nature of interaction between the biomembrane and the drugs involved in their pharmacology.     

Stereochemical aspects of diels-alder reaction of substituted penta-2,4-dienols and maleic anhydride derivatives

Reaction of diene alcohol5 and maleic anhydride in benzene at either room temperature or reflux proceeds probably through a intermolecular Diels-Alder cycloaddition followed by lactone formation to give adduct6.     

Serum vitamin D status and metabolic syndrome: a systematic review and dose-response meta-analysis

BACKGROUD/OBJECTIVESEvidence has suggested an association between serum vitamin D and metabolic syndrome (MetS), but prospective studies are very limited. The objective was to assess the dose-response association between serum vitamin D concentration and MetS risk using a systematic review and meta-analysis of updated observational studies.MATERIALS/METHODSUsing MEDLINE, PubMed, and Embase, a systematic literature search was conducted through February 2020 and the references of relevant articles were reviewed. A random-effects model was used to estimate the summary odds ratio/relative risk and 95% confidence interval (CI). Heterogeneity among studies was evaluated with I² statistic. In total, 23 observational studies (19 cross-sectional studies, and four cohort studies) were included in the meta-analysis.RESULTSThe pooled estimates (95% CI) for MetS per 25-nmol/L increment in serum vitamin D concentration were 0.80 (95% CI, 0.76–0.84; I² = 53.5) in cross-sectional studies, and 0.85 (95% CI, 0.72–0.98; I² = 85.8) in cohort studies. Similar results were observed, irrespectively of age of study population, study location, MetS criteria, and adjustment factors. There was no publication bias for the dose-response meta-analysis of serum vitamin D concentrations and MetS.CONCLUSIONSDose-response meta-analysis demonstrated that a 25-nmol/L increment in the serum vitamin D concentration was associated with 20% and 15% lower risks of MetS in cross-sectional studies and cohort studies, respectively.     

Associations Between Thyroid Hormone Levels and Urinary Concentrations of Bisphenol A,F, and S in 6-Year-old Children in Korea

ObjectivesBisphenol A (BPA) is used in the electrical, mechanical, medical, and food industries. Previous studies have suggested that BPA is an endocrine disruptor. Regulation of BPA has led to increased use of bisphenol F (BPF) and bisphenol S (BPS). However, few studies have investigated the associations of BPF and BPS with thyroid dysfunction in children. Our study investigated the associations of prenatal BPA and early childhood BPA, BPF, and BPS exposure with thyroid function in 6-year-old children.MethodsPrenatal BPA concentrations were measured during the second trimester of pregnancy in an established prospective birth cohort. We measured urinary BPA, BPF, and BPS concentrations and thyroid hormone levels (thyroid-stimulating hormone, total T₃, and free T₄) in 6-year-old children (n=574). We examined the associations between urinary bisphenol concentrations and percentage change of thyroid hormone concentrations using multivariate linear regression. We also compared thyroid hormone levels by dividing the cohort according to BPA, BPF, and BPS concentrations.ResultsThe associations between prenatal BPA and total T₃ levels were statistically significant in all models, except for girls when using a crude model. The associations between urinary BPA and BPS concentrations and levels of all thyroid hormones were not statistically significant. However, we observed that lower free T₄ levels (−1.94%; 95% confidence interval, −3.82 to −0.03) were associated with higher urinary BPF concentrations in girls only.ConclusionsOur findings identified significant associations between prenatal BPA exposure and total T₃ levels in all children and between BPF exposure and free T₄ levels in girls only.     

Dietary Patterns in Runners with Gastrointestinal Disorders

Individuals with inflammatory bowel disease (IBD), irritable bowel syndrome (IBS) and reflux frequently experience gastrointestinal symptoms (GIS), potentially enhanced by high-intensity running. Food avoidances, food choices, and GIS in runners with IBS/IBD (n = 53) and reflux (n = 37) were evaluated using a reliability and validity tested questionnaire. Comparisons to a control group of runners (n = 375) were made using a Fisher’s Exact test. Runners with IBS/IBD experienced the greatest amount of exercise-induced GIS followed by those with reflux. Commonly reported GIS were stomach pain/cramps (77%; 53%), bloating (52%; 50%), intestinal pain/cramps (58%; 33%), and diarrhea (58%; 39%) in IBS/IBD and reflux groups respectively. In the pre-race meal, those with IBS/IBD frequently avoided milk products (53%), legumes (37%), and meat (31%); whereas, runners with reflux avoided milk (38%), meat (36%), and high-fibre foods (33%). When considering food choices pre-race, runners with IBS/IBD chose grains containing gluten (40%), high fermentable oligo-, di-, mono-saccharides and polyols (FODMAP) fruits (38%), and water (38%). Runners with reflux chose water (51%), grains containing gluten (37%), and eggs (31%). In conclusion, while many runners with IBS/IBD and reflux are avoiding trigger foods in their pre-race meals, they are also consuming potentially aggravating foods, suggesting nutrition advice may be warranted.