Modulation of retinal pigment epithelial cell behavior by Agaricus bisporus lectin.

PURPOSE: To determine whether Agaricus bisporus lectin (ABL) binds retinal pigment epithelial cells (RPEs), to conduct a preliminary viability study of RPEs exposed to ABL, and to evaluate the effects of ABL on RPE proliferation and RPE-mediated matrix contraction in vitro. METHODS: Using cultured bovine RPEs, immunohistochemistry was used to study ABL binding. Morphologic and trypan blue exclusion techniques were used for toxicity studies. The effect of ABL on RPE proliferation was investigated by [methyl-3H]-thymidine incorporation. The effect of ABL on RPE-mediated matrix contraction was evaluated with RPE-populated three-dimensional collagen matrices. RESULTS: ABL bound to RPE cells. This binding was inhibited by asialomucin. No change in RPE morphology or trypan blue exclusion compared with controls was observed in RPEs incubated with 5 to 60 microg/ml ABL for 3 days. Twenty-four-hour incubations of RPEs with ABL significantly inhibited RPE proliferation in a dose-dependent way, 40 microg/ml ABL inhibited proliferation by 83% (SE 14, P<0.05). ABL showed a dose-dependent significant inhibition of RPE-mediated collagen matrix contraction over 3 days, with 93% inhibition compared with controls by 40 microg/ml lectin (P<0.05). The inhibitory effect of ABL on proliferation and gel contraction was partly reversible after eliminating ABL from the culture medium. CONCLUSIONS: Bovine RPE cells bind ABL, and preliminary evaluations suggest that levels of ABL that are nontoxic to the cells potently inhibit RPE proliferation and RPE-mediated matrix contraction. ABL deserves further investigation as a potential inhibitor of RPE proliferation and cell-mediated matrix contraction in anomalous reparative processes such as proliferative vitreoretinopathy and as a laboratory tool for RPE behavioral studies.     

Improved detection of rhinoviruses in nasal and throat swabs by seminested RT-PCR

A seminested RT-PCR (nRT-PCR) was used to detect picornavirus (PV) RNA in cell cultures inoculated with rhinoviruses (HRVs) and enteroviruses (EVs). PCR tests in which a primary "touchdown" PCR was followed by secondary reactions using PV or HRV specific primers were able to differentiate HRVs of 48 serotypes from EVs. PVnRT-PCR and HRVnRT-PCR were then used to test nasal and throat swabs from adult subjects with naturally acquired respiratory virus infections. The swabs were also analysed for respiratory viruses by cell culture techniques and the rates of PV identification by the two methods were compared. PVnRT-PCR was found to be at least five times more sensitive than cell culture for the detection of PVs in these clinical specimens. Paired acute and convalescent serum samples were tested for complement fixing antibodies to adenovirus, influenza A and B, respiratory syncytial virus, parainfluenza viruses 1, 2, and 3, Myco plasma pneumoniae, and Chlamydia psittaci. An enzyme-linked immunosorbent assay (ELISA) was used to detect rises in antibody level to coronavirus types 229E and OC43. The overall rate of pathogen identification in 159 swabs from adult asthmatics increased from 28% when only cell culture and serology were used to 57% when these methods were supplemented by PVnRT-PCR. © 1993 Wiley-Liss, Inc.     

Environmental continuity: a social-geographic approach to structural change in lowering health care cost through elderly participation

Tremendous growth in the number of elderly has resulted in the need to consider options for decreasing their need for dependent living, while increasing their level of health. Environmental continuity is supported as one such alternative. An examination of how the elderly relate to their surroundings and their relationships with others enables the identification of social and cultural thresholds beyond which the elderly cannot be expected to predict, participate in, or control events in their environment. "Threshold management" is suggested as a preventive health measure for reducing social disintegration in the elderly and concomitant strains to the health care system and society.     

Reading, Demographic, Social and Psychological Factors Related to Pre-adolescent Smoking and Non-smoking Behaviors and Attitudes

The purpose of this study was to examine reading, demographic, social and psychological factors related to pre-adolescent smoking and non-smoking behaviors and attitudes. The school-home humanistic education program was implemented in a large, urban public school system. It stressed responsible decision-making, increased self-esteem and the inter-relationships among the acquisition of knowledge of the consequences of smoking, personal feelings, family relationships and behavior. The results showed that family involvement was necessary to affect smoking attitudes and behaviors. Of all the variables studied, reading had a most pervasive relationship. Peer influence and self-esteem also were related to smoking knowledge, smoking attitude, future smoking intentions and the "purchase" of cigarettes. Two of several conclusions drawn from the results are: 1. Family involvement is necessary to affect attitudes and behaviors. 2. Health education research that does not investigate the relationship between program outcomes and reading achievement may be misleading.     

Propranolol and atenolol inhibit norepinephrine spillover rate into plasma in conscious spontaneously hypertensive rats

Summary Radiotracer techniques capable of measuring norepinephrine clearance and spillover rate into plasma were used to test the hypothesis that the antihypertensive effects of propranolol and atenolol in conscious spontaneously hypertensive rats are associated with an inhibition of norepinephrine release from postganglionic sympathetic neurons. The 10%–15% fall in mean arterial pressure produced over 4 h by propranolol (1, 3.3 and 10 mg/kg, s. c.) and atenolol (1, 3.3 and 10 mg/kg, s. c.) was not dose-related, and only the largest dose of propranolol caused a significant bradycardia. Each dose of atenolol significantly lowered heart rate. The decrease in blood pressure caused by propranolol and atenolol was not related to the decrease in heart rate. Both propranolol and atenolol inhibited norepinephrine clearance by 12% to 16%. The 1 mg/kg doses of propranolol and atenolol significantly suppressed norepinephrine spillover rate by 21 % and 32%, respectively, at 4 h postinjection. As the dose of propranolol was increased, the inhibition of norepinephrine spillover was reversed as plasma epinephrine concentration rose by 125%. The suppression of norepinephrine spillover rate caused by atenolol was more persistent but did diminish after the 10 mg/kg dose, when plasma epinephrine concentration was elevated by 55%. Both drugs suppressed plasma renin concentration, but the inhibition of norepinephrine spillover rate by propranolol and atenolol was not related to the fall in plasma renin concentration. By comparison, treatment with the adrenergic neuron blocking agent bretylium (5, 10, 20 and 40 mg/kg, s. c.) elicited a dose-related vasodepression with no change in heart rate or plasma renin concentration. The 10 mg/kg dose of bretylium inhibited norepinephrine spillover rate by 40%, but increasing the dose did not produce a further suppression of norepinephrine spillover rate. Bretylium caused a dose-related elevation of plasma epinephrine concentration (354% increase at 40 mg/kg). In a separate study, propranolol (10 mg/kg) and bretylium (40 mg/kg) significantly increased epinephrine spillover rate by 85% and 118%, respectively. Based on these data, we conclude that the -adrenoceptor antagonists lower blood pressure by inhibiting norepinephrine release from postganglionic sympathetic neurons. Send offprint requests to T. K. Keeton at the above address     

Amine Prodrugs Which Utilize Hydroxy Amide Lactonization. I. A Potential Redox-Sensitive Amide Prodrug

Several amides of 3-(3,6-dioxo-2,4-dimethylcyclohexa-l,4-diene)-3,3-diniethylpropionic acid (2) have been synthesized and tested as model redox-sensitive pro-prodrugs of amines. The reduction of these model pro-prodrugs generated hydroxy amide intermediates 4a-4h, the lactonization of which resulted in amine release. The rates of lactonization of 4a-4h were investigated at pH 7.4 and 37°C. The half-lives for appearance of the product lactone la from these intermediates were found to range from 1.4 to 3.4 min. With such rapid lactonization rates, it is believed that reduction will be the rate-limiting step in the two-step conversion of the pro-prodrug to the amine.     

Isolation and characterization of irradiation fusion hybrids from mouse Chromosome 1 for mapping Rmc-1, a gene encoding a cellular receptor for MCF class murine retroviruses

An irradiation-reduced somatic cell hybrid mapping panel was constructed of BALB/c mouse Chromosome 1. Nineteen hybrids were selected from a pool of 292 clones to generate a fine structure physical map of the distal 40 cM of the chromosome. The hybrids contain mouse DNA fragments only from Chromosome 1, ranging from 5 cM to 20 cM. Utilizing a viral infectibility assay, a cellular receptor gene,Rmc-1, for the MCF class of murine retroviruses was found to be linked toLamb2, in the region between theLamb2 andBxv-1 loci. In addition, analysis of the hybrid mapping panel resulted in the remapping of three loci,Atpb, Ly-5, andPmv-24, as compared to the mouse linkage map. Two previously unmapped endogenous proviruses are also putatively assigned positions on the chromosome.     

Reliability of level of care decisions in a Long-Term Care program

This paper addresses the question of the degree of agreement between experienced assessors making level-of-care placement decisions for the same client, given a comparable opportunity to obtain and record client information in a community-based Long-Term Care program.A systematic sample of 246 cases was selected, consisting of 47 preadmission assessments and 199 reviews. The resulting data were subjected to analysis using the statistic Kappa and the degree of agreement categories suggested by Fleiss.¹ It was found that at the level-of-care extremes— Extended Care and Personal Care—the agreement between two nurse assessors for reviews could be considered excellent. In the Intermediate Care range, however, the reliability of the level-of-care decision can only be considered fair. Agreement for initial assessments was less, withK=0.469 indicating, overall, only fair agreement. While there was most often only a one-care-level difference between assessors, the program assessor tended to recommend a higher level than the study or check assessor. This has implications for funding agencies and/or facility planners who must assess the likely care requirements of an increasing number of disabled elderly. From a program management perspective, the preceding analyses allow an objective judgement of the extent of the placement decision problem, if any, and further provide a definition of areas most in need of revision. The value of collaboration between practitioner and researcher is evident in these analyses.Dr. Stark is Director, Division of Health Services Research and Development and Assistant Professor, Department of Health Care and Epidemiology, The University of British Columbia. Dr. Gutman is Director, Gerontology Centre and Associate Professor, Faculty of Interdisciplinary Studies, Simon Fraser University. Dr. Brothers is Research Associate, Division of Health Systems, The University of British Columbia. Address enquiries to Dr. A. Stark, Director, Division of Health Services Research and Development, Office of the Coordinator of Health Sciences, The John F. McCreary Health Sciences Centre, 2194 Health Sciences Mall, The University of British Columbia, Vancouver, B.C., V6T 1Z6.The research described in this paper, as well as the larger study of which it is a part, is supported by a grant from the B.C. Health Care Research Foundation. In addition, the cooperation and support of the Ministry of Health, Province of British Columbia is gratefully acknowledged.     

Protein covalent binding of maxipost through a cytochrome P450-mediated ortho-quinone methide intermediate in rats.

(3S)-(+)-(5-Chloro-2-methoxyphenyl)-1,3-dihydro-3-fluoro-6-(trifluoromethyl)-2H-indole-2-one) (MaxiPost, BMS-204352) is a potent and specific opener for maxi-K channels and has potential to prevent and treat ischemic stroke. Following single intravenous doses of [14C]BMS-204352 to rats, only 10 to 12% of radioactivity was extractable from plasma with organic solvents. The unextractable radioactivity remained associated with the proteins (mostly albumin) after SDS-polyacrylamide gel electrophoresis or dialysis. Following acid hydrolysis in 6 M HCl for 24 h at 110 degrees C from plasma proteins collected from nine rats dosed with [14C]BMS-204352, one major radioactive product was isolated and identified as a lysine-adduct of des-fluoro des-O-methyl BMS-204352 by liquid chromatography/mass spectrometry and NMR analyses as well as by comparison with the synthetic analog, lysine-adduct of des-fluoro BMS-204352 (BMS-349821). The covalent binding of BMS-204352 results from the displacement of the ring-fluorine atom of des-O-methyl BMS-204352 with the epsilon-amino group of a lysine residue. Microsomal incubations of [14C]BMS-204352 resulted in low levels of covalent binding of radioactivity to proteins. This in vitro covalent binding required cytochrome P450-reductase cofactor NADPH and was attenuated by glutathione. P4503A inhibitors ketoconazole and troleadomycin selectively prevented the covalent binding in vitro. Based on these observations, a two-step bioactivation process for the protein covalent binding of BMS-204352 was postulated: 1) P4503A-mediated O-demethylation leading to spontaneous release of HF and the formation of an ortho-quinone methide reactive metabolite and 2) nucleophilic addition of the epsilon-amino group of protein lysine residue(s) in protein to form des-fluoro des-O-methyl BMS-204352 lysine adduct.