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R Anderson

Publications and source records attributed to R Anderson.

At least 307 records · Page 17Linked to original sources
PubMed1994

NADPH-oxidase activity of stimulated neutrophils is markedly increased by serum.

In this study we have investigated the effects of serum (10, 20, and 40% final concentrations) on the activity of NADPH-oxidase and energy metabolism of activated human neutrophils in vitro. Neutrophils were stimulated with FMLP, PMA, or opsonized zymosan in the presence and absence of serum, and generation of reactive oxidants by intact cells was measured using lucigenin-enhanced chemiluminescence (LECL). This method was also used to measure NADPH-oxidase activity in purified membrane preparations from neutrophils activated with PMA in the presence or absence of serum. Cellular ATP levels and activities of the various glycolytic enzymes were assayed using CL and spectrophotometric procedures, respectively. Inclusion of serum with neutrophils during exposure to the various stimuli of membrane-associated oxidative metabolism caused significant enhancement of the LECL responses of intact cells as well as of the activity of NADPH-oxidase in purified membranes prepared from PMA-activated neutrophils. In the absence of serum, the ATP levels and activity of glyceraldehyde-3-phosphate dehydrogenase (G3PDH), but not the other glycolytic enzymes, were decreased in activated neutrophils, while inclusion of serum preserved neutrophil ATP levels and activity of G3PDH. Serum supplementation of the cell-suspending medium appears to promote optimum activity of NADPH-oxidase in stimulated neutrophils by preventing premature, oxidative inactivation of cellular energy metabolism.

Adenosine Triphosphate↗
PubMed1994

Oxidant-mediated ciliary dysfunction in human respiratory epithelium.

Exposure of human nasal ciliated epithelium to reactive oxidants generated by the enzymatic xanthine-xanthine oxidase superoxide/hydrogen peroxide (H2O2) and glucose-glucose oxidase H2O2-generating systems, or to reagent H2O2 or hypochlorous acid (HOCl) resulted in significant alterations in ciliary beating. The earliest change noted was the presence of ciliary slowing, progressing eventually to complete ciliary stasis in some areas. Ciliary dyskinesia was seen within the first hour, often from as early as 15 min after exposure of the cells to reactive oxidants. Using peroxidases, various antioxidant enzymes, and oxidant scavengers, we confirmed that these detrimental effects on ciliary function were mediated primarily by H2O2 and HOCl. Moreover, 3-aminobenzamide (3-ABA), an inhibitor of the DNA repair enzyme poly ADP ribose polymerase, prevented H2O2-mediated inhibition of ciliary function, indicating that oxidant-mediated damage to DNA may well be the basis of the effects of H2O2 on ciliated epithelium. Acute and chronic inflammatory responses may therefore present the possible threat of H2O2- or HOCl-inflicted injury on bystander respiratory epithelium, leading to ciliary dyskinesia and slowing.

Catalase↗
PubMed1994

Relationship of sociotropy/autonomy and dependency/self-criticism to DSM-III-R personality disorders.

Relationships between Beck's constructs of sociotropy/autonomy and Blatt's constructs of dependency/self-criticism and the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; American Psychiatric Association, 1987) Axis II personality disorders were examined. Two measures of personality styles and a structured diagnostic interview for personality disorders were administered to 138 outpatients. Significant relationships were found between both sets of constructs and a number of personality disorders using both categorical and dimensional measures of Axis II psychopathology. These relationships were consistent with previous theory, supporting recent conceptualizations extending the range of psychopathology associated with these personality styles from depression to the personality disorders. However, the autonomy/self-criticism dimension was correlated with a broader range of personality disorder traits and diagnoses than anticipated.

Adult↗
PubMed1994

The new AONE.

Explore the source record for details and available documents.

Humans↗
PubMed1994

Trial of labor following cesarean delivery.

OBJECTIVE: To examine several variables that may affect the success rate for a trial of labor after previous cesarean delivery, as well as those affecting the rate of uterine rupture. METHODS: Between June 1, 1990 and December 31, 1991, we performed a consecutive, prospective study of 593 pregnant women who had had at least one abdominal delivery in the past, and attempted a trial of labor in each. Particular attention was given to the success rate of vaginal delivery, the type of previous uterine incision, use of oxytocin, estimated maternal blood loss, 5-minute Apgar scores, and reason for the previous cesarean operation. RESULTS: Four hundred seventy-eight patients (81%) had a successful vaginal delivery. Oxytocin induction or augmentation was successful in 46 of 67 (69%) and 117 of 167 cases (70%), respectively. Estimated maternal blood loss was less than 500 mL in 453 cases (95%). Five patients (0.8%) experienced true uterine rupture, resulting in severe neurologic sequelae in one infant. The only consistent indication of uterine rupture was an abrupt and prolonged fetal bradycardia. The majority (463; 97%) of infants who were delivered vaginally had 5-minute Apgar scores of 8 or greater. CONCLUSION: Our success rate of 81% suggests that a trial of labor after previous cesarean delivery is a safe and desirable option, but only after thorough patient counseling. An abrupt and persistent fetal bradycardia may be the only indication that uterine rupture has occurred.

Apgar Score↗
PubMed1994

Expression of the Bordetella pertussis P.69 pertactin adhesin in Escherichia coli: fate of the carboxy-terminal domain.

The mature pertactin protein (P.69) of Bordetella pertussis can be isolated from the bacterial cell surface as a polypeptide with an apparent molecular mass of 69,000 Da as determined by sodium dodecyl sulphate gel electrophoresis. However the open reading frame of prn, the pertactin gene, encodes a polypeptide with a predicted molecular mass of 93,478 Da, referred to as P.93. Expression of the prn gene in Escherichia coli leads to the synthesis of the full-length P.93 polypeptide, which is rapidly processed to the mature P.69 protein located at the cell surface. The P.93 precursor polypeptide is processed at both termini. A 34 amino acid long signal sequence is removed from the amino-terminus and a polypeptide sequence of about 30,000 Da (P.30) is cleaved from the carboxy-terminus. Deletion of the 3' region of prn, encoding P.30, results in the expression of an intracellular form of P.69. Antiserum which recognizes P.30 was raised using synthetic peptides based on the primary amino acid sequence of the region. This anti-P.30 serum was used in a Western blot analysis of fractionated cells of B. pertussis and E. coli harbouring the intact prn gene. The P.30 polypeptide was readily detected in outer membrane fractions prepared from both of these bacterial species, although it could not be shown to be exposed at the cell surface.

Amino Acid Sequence↗
PubMed1994

Characterization of the adenosine receptors mediating hypothermia in the conscious mouse.

1. The effects of a range of adenosine receptor-selective ligands on body temperature were investigated following intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) injection in conscious mice. The compounds tested were the non-selective adenosine receptor agonist 5'-N-ethyl-carboxamidoadenosine (NECA), the adenosine A1 receptor-selective agonists cyclopentyl-adenosine (CPA), N6-(9R-phenyl-isopropyl)-adenosine (R-PIA) and N-(1S,trans)-[2-hydroxyclopentyl]-adenosine (GR79236), the A2a receptor selective agonist 2-[p-(2-carboxyethyl)phenethylamino]-5'-N-ethylcarboxyamidoaden osine (CGS-21680), the A2b receptor agonist N-[(2-methylphenyl)methyl[adenosine (metrifudil) and the A3 receptor agonist N6-(4-aminophenylethyl)adenosine (APNEA). 2. NECA (0.01-1 microgram, i.c.v.), all of the A1-selective agonists (0.01-1 microgram, i.c.v.) and APNEA (0.1-3 micrograms i.c.v.) produced profound and dose-related hypothermia and sedation. However, CGS-21680 (0.1-10 micrograms i.c.v.) and metrifudil (0.01-1 microgram i.c.v.), produced only mild hypothermia at the highest doses tested. 3. The hypothermic response to the A1 receptor-selective agonists, GR79236 and R-PIA was dose-dependently antagonized by peripheral administration of either the non-selective adenosine receptor antagonist, 8-phenyltheophylline (8-PT, approximately 40 and 30 fold rightward shifts of the dose-response curves respectively at 10 mg kg-1, i.p.), or the adenosine A1 receptor-selective antagonist, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, approximately 20 fold shift of the GR79236 dose-response curve at 1 mg kg-1, i.p.). The hypothermic response to APNEA was similarly dose-dependently antagonized by the A1 receptor-selective antagonist, DPCPX (5 fold shift at 0.1 mg kg-1, i.p.). 4.8(p-Sulphophenyl)theophylline (8-SPT, 10 and 30 mg kg-1, i.p.), a non-selective adenosine receptorantagonist that penetrates the blood brain barrier poorly, produced only modest antagonism (approximately 2 fold shift at 30 mg kg-1, i.p.) of the hypothermic response to GR79236.5. These data suggest that hypothermia induced by adenosine analogues in the conscious mouse is mediated via adenosine A1 receptors, which are probably located in the CNS.

Adenosine↗
PubMed1994

Antibody-dependent enhancement of respiratory syncytial virus infection by sera from young infants.

Respiratory syncytial virus (RSV) convalescent-phase sera and control sera from both infants ( < 6 months) and older individuals (1.5 to 90 years) were assayed for RSV-specific antibodies by neutralization, in vitro enhancing activity, and immunoprecipitation. Enhancement of RSV infection in U937 cells was demonstrated with convalescent-phase sera and was shown to be dependent on Fc receptors by blocking with human immunoglobulin G (P < 0.01). Convalescent-phase sera from infants enhanced infection at concentrations closer to physiological ones (10(-1) to 10(-3) dilutions of serum), while convalescent-phase sera from older individuals enhanced infection only at much lower concentrations (10(-3) to 10(-6) dilutions of serum; P < 0.01). To our knowledge, this is the first report of RSV-enhancing antibody activity in the sera of infants. The observed enhancing activity and the low neutralizing antibody levels are confined mostly to convalescent-phase sera from infants aged 0 to 6 months, suggesting that these factors may contribute to the increased severity of RSV disease frequently encountered in young infants.

Adolescent↗
PubMed1994

Investigation of the relative contributions of cigarette smoking and mineral dust exposure to activation of circulating phagocytes, alterations in plasma concentrations of vitamin C, vitamin E, and beta carotene, and pulmonary dysfunction in South African gold miners.

OBJECTIVES: To determine the relative effects of cigarette smoking and mineral dust exposure on numbers and activity of circulating phagocytes, plasma nutritional antioxidant state, and pulmonary function in South African gold miners. METHODS: Pulmonary function was assessed spirometrically, whereas reactive oxidant generation by circulating phagocytes, and plasma concentrations of the nutritional antioxidative nutrients vitamin C and vitamin E and beta carotene were measured with chemiluminescence, spectrophotometry, or high performance liquid chromatography respectively. RESULTS: Cigarette smoking, but not mineral dust exposure, was associated with increased numbers and pro-oxidative activity of circulating neutrophils and monocytes, decreased plasma concentrations of vitamin C, and pulmonary dysfunction. DISCUSSION: In this study group occupational exposure to mineral dust has not been found to promote increases in the numbers or reactivity of circulating phagocytes or to be a significant cause of pulmonary dysfunction, the changes found being due primarily to cigarette smoking.

Adult↗
PubMed1994

Ethnic differences in stroke mortality between non-Hispanic whites, Hispanic whites, and blacks. The National Longitudinal Mortality Study.

BACKGROUND AND PURPOSE: Although US blacks are known to have an excess stroke mortality compared with US whites, little is known about the stroke burden of the Hispanic white population. This report will provide estimates of the relative burden of stroke mortality in the US black and Hispanic population relative to the white population and examine the consistency of this relation across age. METHODS: Data were from participants aged > 45 years from the National Longitudinal Mortality Study. There were 1844 stroke deaths among 239,734 non-Hispanic whites, 46 deaths among 12,527 Hispanic whites, and 234 deaths among 23,468 black participants. Standard statistical methods were used to examine the ethnic differences in stroke mortality. RESULTS: The hazard ratios for black men and women (relative to non-Hispanic whites) were nearly identical, at > 4.0 at age 45 but marginally < 1.0 by age 85. For both Hispanic men and women, the hazard ratios (relative to non-Hispanic whites) were approximately 1.0 at age 45 but were marginally significantly < 1.0 at older ages. The ethnic differences in stroke death rates reveal differences in age distributions of age at fatal stroke between these groups. Approximately 6% of fatal strokes for non-Hispanic whites occurred before age 60, whereas > 15% occurred in both Hispanic whites and blacks. CONCLUSIONS: These results suggest that (1) for Hispanics, stroke risk is similar to that for non-Hispanic whites at young ages but is marginally lower at older ages, (2) the excess stroke mortality in blacks mainly occurs at younger ages (between 45 and 55 years), and (3) the relation between stroke risk for blacks and Hispanics relative to whites is similar by sex. The impact of age on relative stroke mortality would argue against simple age adjustment for describing ethnic differences in stroke mortality. Finally, proportionally, more strokes occur at older ages in non-Hispanic whites than in either US blacks or Hispanic whites.

Age Factors↗
PubMed1994

Effect of chronic theophylline therapy on brain blood flow and function in adult asthmatics.

The impact of theophylline therapy on neuropsychological (NP) function in adult asthmatics is unclear. Additionally, whether the previously demonstrated acute reduction in cerebral blood flow (CBF) persists with continued administration of theophylline, or whether accommodation develops, has not been previously reported. We examined the effects of chronic theophylline administration on CBF and NP function in adults with mild to moderate asthma. Sixty adult patients with mild to moderate asthma were entered into this double-blind, placebo-controlled, crossover, random sequence study. Subjects received theophylline or placebo for 6 wk interposed with a 2-wk washout period. At the conclusion of Week 1 and Week 6 of each drug phase, patients received NP testing, and CBF was determined using the 133Xenon washout method. Forty-three patients completed the study. Theophylline administration was associated with small (6%), but statistically significant, reductions in CBF after both 1 and 6 wk of treatment. No differences consequent to theophylline administration were observed in any of the tests of NP function after 1 or 6 wk of therapy. While CBF was decreased after theophylline, the changes were small compared with previously reported decrements in CBF immediately after theophylline administration.

Adult↗
PubMed1994

Dietary cholesterol and downregulation of cholesterol 7 alpha-hydroxylase and cholesterol absorption in African green monkeys.

In this study, hepatic production of bile acid was considered together with intestinal cholesterol absorption as potential regulatory sites responsive to dietary cholesterol. Sequential liver biopsies were taken from 45 feral African green monkeys studied during three different diet periods. Low-fat Monkey Chow was fed during the baseline period, a cholesterol and fat-enriched diet was then fed for 12 wk during period 2, and finally, after a washout period of 10 wk, three subgroups were fed low-, moderate-, and high-cholesterol diets for 12 mo during period 3. The percentage of cholesterol absorbed in the intestine was significantly lower when higher levels of cholesterol were fed; however, this percentage was significantly and positively correlated to plasma cholesterol concentration at each dietary cholesterol level. Hepatic free and esterified cholesterol content were significantly elevated by dietary cholesterol challenge and remained elevated even after 20 wk of low-cholesterol diets. Hepatic mRNA abundance for cholesterol 7 alpha-hydroxylase (C7H) was significantly lower (approximately 60%) when the high-cholesterol diet was fed, with the decrease being greater than that seen for low density lipoprotein (LDL) receptor mRNA. At the same time, hepatic mRNA abundance for apolipoprotein B and hepatic lipase were not diet sensitive. C7H activity was decreased to a similar extent by diet as was C7H mRNA, although the correlation between enzyme activity and mRNA abundance was only r = 0.5, suggesting that dietary regulation includes factors in addition to transcriptional regulation. Activity and mRNA abundance of C7H remained decreased when liver esterified cholesterol content was reduced to only a two- to three-fold elevation over baseline, at a time when plasma cholesterol and hepatic LDL receptor mRNA abundance had returned to baseline levels. These data on liver C7H, obtained in one of the few primate species predisposed to cholesterol gallstone formation, support the hypothesis that the liver may attempt to downregulate intestinal cholesterol absorption by decreasing bile acid production when increased amounts of absorbed dietary cholesterol reach the liver. Presumably this represents attempted downregulation of intestinal cholesterol absorption by limiting bile acid availability as a means to maintain hepatic cholesterol balance.

Animals↗
PubMed1994

First trimester biochemical screening for trisomy 21: the role of free beta hCG, alpha fetoprotein and pregnancy associated plasma protein A.

The potential efficacy of screening for trisomy 21 in the first trimester, using maternal serum markers alpha fetoprotein, free beta human chorionic gonadotropin, unconjugated oestriol and pregnancy associated plasma protein A, was studied in an unselected population of women between the seventh and fourteenth week of gestation. Using a combination of alpha fetoprotein and free beta human chorionic gonadotropin, 53% of affected pregnancies could be identified at a false positive rate of 5%. Unconjugated oestriol and pregnancy associated plasma protein A levels were lower in cases of trisomy 21, but their inclusion with other markers did not significantly improve detection rate. Monitoring the same pregnancies also in the second trimester showed that screening in the first trimester identified the same cases as in the second. We conclude that first trimester screening using free beta human chorionic gonadotropin and alpha fetoprotein, is a viable possibility and will lead to detection rates in excess of 50%. Prospective studies are needed to confirm these observations.

Adolescent↗
PubMed1994

Characterization of exposure and dose of man made vitreous fiber in experimental studies.

The use of fibrous test materials in in vivo experiments introduces a number of significant problems not associated with nonfibrous particulates. The key to all aspects of the experiment is the accurate characterization of the test material in terms of fiber length, diameter, particulate content, and chemistry. All data related to fiber properties must be collected in a statistically sound manner to eliminate potential bias. Procedures similar to those outlined by the National Institute of Occupational Safety and Health (NIOSH) or the World Health Organization (WHO) must be the basis of any fiber characterization. The test material to which the animal is exposed must be processed to maximize the amount of respirable fiber and to minimize particulate content. The complex relationship among the characteristics of the test material, the properties of the delivery system, and the actual dose that reaches the target tissue in the lung makes verification of dose essential. In the case of man-made vitreous fibers (MMVF), dose verification through recovery of fiber from exposed animals is a complex task. The potential for high fiber solubility makes many of the conventional techniques for tissue preservation and digestion inappropriate. Processes based on the minimum use of aggressive chemicals, such as cold storage and low temperature ashing, are potentially useful for a wide range of inorganic fibers. Any processes used to assess fiber exposure and dose must be carefully validated to establish that the chemical and physical characteristics of the fibers have not been changed and that the dose to the target tissue is completely and accurately described.

Animals↗
PubMed1994

Relationship between lung biopersistence and biological effects of man-made vitreous fibers after chronic inhalation in rats.

This article describes the relationship between fiber biopersistence and the chronic toxicity of different chemical compositions of man-made vitreous fibers (MMVF) in the lung. Rats were exposed in "nose-only" inhalation chambers, 6 hr/day, 5 days/week, for 24 months to aerosol concentrations of 30 mg/m3 containing comparable fiber numbers and similar dimensions of fibrous glass (FG) or refractory ceramic fiber (RCF). Interim sacrifices were performed periodically to monitor fiber number and dimensions in the lung and the progression of pulmonary alterations. At each interim sacrifice, three to six recovery animals were removed from each exposure group and held until two years to determine the biopersistence of fibers after different exposure times. Fibers were recovered from the ashed lungs, counted, and measured using optical and scanning electron microscopy (SEM). Fiber chemistry was assessed in 91-week recovery lungs using energy dispersive spectroscopy (EDS) analysis. RCF induced lung fibrosis and an elevation in lung tumors and pleural mesotheliomas. FG exposure resulted in no lung fibrosis, no statistically significant increase in the lung tumor incidence, and no mesotheliomas. After two years of continuous exposure, the number of World Health Organization fibers per milligram dry lung recovered from RCF and FG exposed lungs was comparable. EDS analysis of recovery lungs showed that most of the alkalis and alkaline earths had leached from the FG fibers over time. A slight change in RCF chemistry was observed. These findings indicate that the change in the chemical composition of fibers may be an important determinant of the chronic toxicity of MMVFs.

Administration, Inhalation↗
PubMed1994

An experimental approach to the evaluation of the biopersistence of respirable synthetic fibers and minerals.

The biopersistence of fibers and minerals in the respiratory tract is an important parameter in the toxicity of those materials. The biopersistence of respirable synthetic fibers and minerals in man can be most closely evaluated in an animal model. While acellular and in vitro systems are important for initial evaluation of solubility and durability, they cannot simulate the dynamics of inhalation deposition and clearance and the subsequent systemic reaction to fibers and minerals that occurs in the animal. To evaluate the biopersistence of synthetic fibers, male rats were exposed to a well defined rat respirable aerosol of man-made vitreous fibers (MMVF), 6 hr/day for 5 days. Following exposure, subgroups were sacrificed at intervals ranging from 1 hr to 52 weeks. Following sacrifice, the lungs were removed, weighed, and immediately frozen at 20 degrees C for subsequent digestion by low temperature plasma ashing. The number, size distribution, and chemical composition of the fibers in the aerosol and lung were determined. With this animal model the role of biopersistence in altering the geometry and clearance of fibers can be systematically evaluated. The model also can be applied for the evaluation of the biopersistence of nonfibrous minerals.

Air Pollutants↗