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A B Anderson

Publications and source records attributed to A B Anderson.

At least 19 recordsLinked to original sources
PubMed1998

On the accommodation of disease rate correlations in aggregate data studies of disease risk factors.

Prentice and Sheppard (1995, Biometrika 82, 113-125) proposed a method for estimating relative risks associated with poorly measured exposures using disease rates from multiple populations and exposure and confounding factor data from sample surveys of persons in each population. The method involved an assumption of independence of disease rates across populations, conditional on exposures and confounding factors. Here, this assumption is relaxed by allowing dependencies among the disease rates within a partition of the populations, perhaps defined on the basis of geographic proximity or cultural similarity. Such dependencies could, for example, derive from unmeasured risk factors that are shared among neighboring populations. Dependencies within an element of the partition are modeled by allowing a common correlation between the disease rates of contiguous populations and by inducing correlations between the rates for noncontiguous populations using a multivariate lognormal assumption. Estimating equations are proposed for relative risk parameter estimation, and robustness and efficiency properties are assessed through simulations. The relaxed estimation procedure is shown to yield useful efficiency gains when moderate or strong disease rate dependencies are present, especially when disease rate variances are large relative to binomial variance.

Aged↗
PubMed1996

Platelet deposition and fibrinogen binding on surfaces coated with heparin or friction-reducing polymers.

The blood-contacting properties of polyethylene coated with a lubricious hydrophilic coating; an uncoated polyethylene; or a photoheparin-treated polyethylene-negative control sample were compared by measuring fibrinogen adsorption, antifibrinogen binding, and platelet attachment from human plasma. The polyethylene surfaces coated with a hydrophilic polymer were found to be similar to surfaces coated with heparin. Fibrinogen adsorption on the hydrophilic coating was 60% lower than adsorption on either the uncoated or heparin-coated polyethylene samples. Antifibrinogen binding from buffer to the hydrophilic coating was also reduced more than 85% from binding to uncoated polyethylene samples. Both the hydrophilic coating and heparin coating showed a reduction in platelet attachment by a factor of 100 over the uncoated sample as well as significantly reduced platelet activation.

Acrylic Resins↗
PubMed1995

Absorption spectra indicate conformational alteration of myoglobin adsorbed on polydimethylsiloxane.

To assess the effects of adsorption on protein structure, ultraviolet optical absorption spectra of myoglobin (Mb) bound to polydimethylsiloxane (PDMS) were measured. A flow cell, which enabled adsorption under controlled hydrodynamic conditions, was used in conjunction with a conventional spectrophotometer to obtain the spectra. Adsorption to PDMS reduced significantly the absorbance in the Soret region of the Mb spectrum, whereas the spectrum in the region near 280 nm was essentially unaffected. This result showed that disruption of the native structure of Mb occurs following interaction with PDMS. Furthermore, the change in the absorption spectrum may indicate loss of heme from the heme pocket of the adsorbed protein. Mb structure was altered from its solution configuration within fifteen min of contact with the surface. Exchange of adsorbed Mb with Mb in solution had little or no effect on the absorption spectrum of the surface-confined protein, indicating that exchange occurs only between conformationally altered species or between native species.

Adsorption↗
PubMed1994

Environmental equity: the demographics of dumping.

Research addressing "environmental equity" and "environmental racism" claims that facilities for treatment, storage, and disposal of hazardous wastes (TSDFs) are located disproportionately in minority areas. In the first comprehensive study of TSDFs to use census tract-level data, we find no nationally consistent and statistically significant differences between the racial or ethnic composition of tracts which contain commercial TSDFs and those which do not. TSDFs are more likely to be found in tracts with Hispanic groups, primarily in regions with the greatest percentage of Hispanics. Different geographic units of analysis elaborate on, but are consistent with, these results.

Black or African American↗
PubMed1991

The clinical utility of pulse oximetry in the pediatric emergency department setting.

Pulse oximetry provides a noninvasive, painless, accurate, and rapid method for measuring arterial oxygen saturation (SaO2). It has been shown to be valuable in anesthesia and critical care and recently has been used extensively in the outpatient setting. As is often the case with new technologies, little has been published on the basic issues of reliability, reproducibility, and effect on patient care. This prospective clinical study evaluated the basic principles of pulse oximetry in the pediatric emergency department setting and tested the hypotheses that pulse oximetry SaO2 measurements are reliable and provide valuable information, in addition to clinical and laboratory data which affect patient assessment and management. One hundred twenty patients were enrolled in phase 1 and 437 in phase 2 of the study. Pulse oximetry readings were reproducible with an intraclass correlation of 0.87. SaO2 measurements changed the assessed degree of illness in 188 (53%) patients; 47 (13%) were felt to be more ill and 130 (37%) to be less ill than at initial assessment. Sixty-nine (17%) patients were identified in whom SaO2 readings changed management plans; 27 (8%) were managed more aggressively (intubation, surgery, or admission), while 40 (11%) were managed less aggressively (discharged). In three cases, pulse oximetry was instrumental in the diagnosis of a serious illness. The results from this study indicate that pulse oximetry SaO2 readings are stable and reproducible and provide information which impacts significantly on patient assessment and management.

Adolescent↗
PubMed1990

Local anesthesia in pediatric patients: topical TAC versus lidocaine.

Lacerations requiring sutures are a common surgical emergency in children. Traditional anesthesia prior to suturing has been intradermal lidocaine. TAC (0.5% tetracaine, 1:2,000 adrenalin, 11.8% cocaine) is a topically applied anesthetic. A randomized, placebo-controlled, double-blind clinical study was conducted to test the hypothesis that topical TAC and intradermal lidocaine are equally efficacious with respect to patient compliance with the suturing process, ie, anesthetic application and placement of sutures, and development of wound complications. Patients less than 18 years old, with lacerations 5 cm or less in length, located in well vascularized, nonmucous membrane areas were included. Patients were entered into the intradermal or topical groups; the intradermal group received lidocaine and the topical group was randomized to receive either TAC or placebo. One hundred fifty-one patients were enrolled in the study. There was no significant difference in the rates of successful initial anesthesia with TAC (89%) and lidocaine (79%). TAC was significantly better (P less than .002) with regard to patient compliance with the suturing process than lidocaine or placebo. Seventeen percent of patients who received placebo had initial anesthesia. These results suggest that TAC, when applied correctly, may be the preferred anesthetic for laceration repair in children.

Administration, Topical↗
PubMed1989

Duration of fever prior to onset of a simple febrile seizure: a predictor of significant illness and neurologic course.

This study tested the hypothesis that the duration of fever prior to the onset of a simple febrile seizure may be an important clinical variable with respect to patient outcome. The duration of fever prior to seizure according to patient history was defined as either long (greater than or equal to 24 hours) or short (less than 24 hours). We hypothesized that simple febrile seizures which occur with a history of a fever of long duration (LDF) are more likely to be associated with a significant illness at presentation or a subsequent neurologically abnormal course than are simple febrile seizures which occur with a history of a fever or short duration (SDF). Of 100 cases which met study criteria for simple febrile seizures, nine had a LDF and 91 had a SDF prior to the development of a seizure. No statistical differences in age, sex, maximum fever recorded in the emergency department, duration of seizure, WBC, or electrolytes were found between patients with SDF and LDF (P less than 0.01). Of the nine patients with a LDF, all had either a significant illness at the time of initial visit or a subsequent neurologically abnormal course. Of the 91 patients with a SDF, 88 had a good outcome, while two had a significant illness at the time of visit, and one had a subsequent neurologically abnormal course. These results suggest that children with a history of LDF prior to the occurrence of a simple febrile seizure are more likely to have a serious illness at presentation or a subsequent neurologically abnormal course than are children with seizures which occur with a history of SDF.

Bacterial Infections↗
PubMed1988

Effector mechanism of tumor immunity in murine plasmacytoma.

The development of concomitant tumor immunity to plasmacytoma (PC) was previously demonstrated by the detection of splenic immune T-lymphocytes that inhibited the growth of PC in local adoptive transfer (Winn) assay. This immunity was down-regulated by cyclophosphamide-sensitive suppressor T-cells. The effector mechanism was further studied. It was found that immune spleen cells contained no cytotoxic T-lymphocytes as determined by 51Cr release assay. Immune spleen cells, however, exerted a cytostatic effect on PC cells in vitro; coculture of immune spleen cells with PC cells inhibited the [3H]thymidine uptake by tumor cells. No in vitro generation of cytolytic activity was observed. The cytostatic effector cells were found to be radiosensitive, nonadherent, Thy-1+, Lyt-1-2+ lymphocytes that required direct cell-cell contact for cytostasis. Plasmacytoma arising from transplants of mixtures of PC cells and immune spleen cells had a slower growth rate in vivo and incorporated less [3H]thymidine in vitro, findings consistent with the cytostatic effect of immune spleen cells. Studies comparing cytostatic cells assayed in vitro and immune splenic effector cells assayed in vivo (Winn assay) revealed that the former were short-lived (less than 26 days), high dose cyclophosphamide (200 mg/kg) resistant, and cross-reacting to other PC, whereas the latter were long-lived (greater than or equal to 102 days), high dose cyclophosphamide sensitive, and individual tumor specific. Immune spleen cells, however, could inhibit heterologous PC growth in vivo, if the homologous PC were also present. These findings are consistent with the hypothesis that the concomitant tumor immunity in PC involves terminal cytostatic effector T-cells with a broader target spectrum and tumor-specific helper T-cells that are required for clonal expansion and maturation of cytostatic cells in vivo.

Animals↗
PubMed1987

The influence of steroid hormones on the uterine cervix during pregnancy.

This paper reviews the evidence concerning the actions of steroid hormones on the connective tissues of the pelvis. Most available data concern the effects of steroids on the cervix. The time course of cervical softening in rats, sheep and humans suggests the possibility that the changes in connective tissue biochemistry that underlie the physiological phenomenon of cervical softening are under hormonal control. Both oestrogens and progestogens have been implicated in the control of cervical softening. However, recent experiments using inhibitors of 3 beta-hydroxysteroid dehydrogenase suggest that cervical softening can be produced in both sheep and humans by progesterone withdrawal in the absence of high circulating concentrations of oestradiol-17 beta.

3-Hydroxysteroid Dehydrogenases↗
PubMed1987

Latent oculogenital infection with Chlamydia trachomatis.

Thirty patients attending a sexually transmitted disease clinic were evaluated for genital and ocular infection with chlamydia. Eight patients had positive conjunctival immunofluorescent staining. This represents an asymptomatic, latent carrier state with important epidemiologic considerations.

Chlamydia Infections↗
PubMed1987

Haemophilus influenzae type b unsuspected bacteremia.

To further define the clinical features and natural history of unsuspected Haemophilus influenzae type b (Hib) bacteremia, we retrospectively reviewed the records of 322 Hib infections observed during a 45-month period at Children's Hospital, Boston. We identified 31 patients with unsuspected Hib bacteremia and 19 with unsuspected Hib antigenemia and sterile blood cultures. Bacteremic patients were typically under two years of age (81%), had high fevers (mean = 39.5 degrees C), and frequently had otitis media (65%) diagnosed as their only focus of infection at presentation. Nineteen of 31 were empirically treated with oral antibiotics. Ten of 31 (32%) developed focal infectious complications consisting of meningitis (n = 7), cellulitis (n = 2), and pneumonia (n = 1). Children with focal infectious complications differed from those without infectious complications in having a significantly higher mean fever of 40.3 degrees C compared to 39.7 degrees C (P less than 0.05). Five of 19 (26%) empirically treated patients developed focal complications (all meningitis) compared to five of 12 (42%) untreated patients. Blood cultures at follow-up visit were positive in three of 19 (9%) treated patients and seven of 12 (42%) untreated patients (P less than 0.05). Of the 19 children with antigenemia and sterile blood cultures, 16 (84%) were empirically treated with antibiotics, and none had positive blood cultures or focal infections on follow-up evaluation. Children with occult Hib bacteremia are at high risk for developing serious focal infections, particularly meningitis, despite empiric antibiotic therapy. Once Hib bacteremia is suspected, strong consideration should be given to parenteral in hospital antibiotic therapy. The utility of rapid antigen detection for identifying high-risk patients requires further evaluation.

Antigens, Bacterial↗
PubMed1985

Increase in cervical extensibility during labor induced after isolation of the cervix from the uterus in pregnant ewes.

Surgical transection of the cervix was done on eight ewes in late pregnancy. This procedure resulted in most of the length of the cervix being mechanically disconnected from the uterus. Labor was induced by injection of dexamethasone phosphate into a fetal hind limb during operation in four of the eight ewes. The success of the induction of labor was confirmed by observation of increased uterine activity and by measurement of the concentrations of progesterone and 17 beta-estradiol in peripheral plasma. Ewes were put to death approximately 48 hours after injection of dexamethasone and the extensibility of the isolated portion of the cervix was determined. Cervices taken from ewes in which labor had been induced were found to have softened considerably compared to control cervices taken from ewes in which the cervix had been transected without induction of labor. The results suggest that cervical softening can still occur during labor in the absence of any direct mechanical or local vascular connection between the cervix and uterus.

Animals↗
PubMed1985

Population structure in the Connecticut Valley: II. A comparison of multidimensional scaling solutions of migration matrices and isonymy.

In a previous paper (Swedlund et al., 1984) we have described the population structure of the historical Connecticut River Valley of Massachusetts in terms of matrimonial migration matrices. Using procedures described by Morton (1973), Harpending and Jenkins (1974), Jorde (1980), and others the exchanges between subdivisions which make up the matrices are made column stochastic and analyzed to predict genetic kinship. Subsequently the kinship estimates within and between subdivisions can be interpreted as genetic covariance and compared to the actual geographic distances between the respective subdivisions using a principal components analysis. In the present paper we extend these results by applying nonmetric multidimensional scaling to the migration matrices, and to isonymy matrices based on the same communities. We demonstrate that the multidimensional scaling configurations of marital migration represent the actual geographic relationships between the communities quite effectively for this particular case study from historical Massachusetts. Moreover, we argue that while these migration data may provide good estimates of social and genetic exchange between the subdivisions, surname analysis may also be informative of processes not revealed in the migration matrices alone.

Demography↗
PubMed1985

Effect of inhibition of prostaglandin synthesis on cervical softening and uterine activity during ovine parturition resulting from progesterone withdrawal induced by epostane.

The effects of an inhibitor of 3 beta-hydroxysteroid dehydrogenase (epostane) on uterine activity and cervical softening have been studied in eight sheep during late pregnancy. Treatment with epostane led to a rapid decline in the concentration of progesterone measured in utero-ovarian venous plasma, to less than 10% of the pretreatment value within 30 min of bolus injection. This was followed by a significant (P less than 0.02) increase in the concentrations of metabolites of prostaglandins E and F in utero-ovarian venous plasma and uterine activity similar to that seen in the final stages of normal labour. Measurements of cervical tissue extensibility made ex vivo showed the cervix to have softened considerably. These changes occurred without any significant change in the concentration of oestradiol-17 beta in utero-ovarian venous plasma. Infusion of mefenamic acid, an inhibitor of prostaglandin synthesis, prevented the changes in uterine activity and cervical softening that occurred after injection of epostane alone. Mefenamic acid also reduced the increase in concentrations of metabolites of prostaglandins E and F in plasma, although the concentration of progesterone in these animals showed the same abrupt fall which occurred in sheep after injection of epostane alone. These results suggest that progesterone withdrawal, in the absence of any subsequent rise in circulating oestrogen concentrations, is sufficient stimulus to induce cervical softening in the ewe. Cervical softening following progesterone withdrawal can be prevented by inhibition of prostaglandin synthesis.

3-Hydroxysteroid Dehydrogenases↗
PubMed1985

Splenic immune effector and suppressor cells in mice bearing a growing plasmacytoma.

The occurrence of tumor immunity in mice bearing a growing plasmacytoma (PC) was studied by local adoptive transfer assay. Spleen cells from mice with a large PC but not with a nonpalpable or small PC retarded and often inhibited entirely the growth of homologous PC. They occasionally caused late regression of growing homologous and heterologous PC. The individual tumor-specific immune effector cells were found to be radiosensitive, non-adherent, Thy 1-positive T-cells. They were resistant to treatment of mice with high-dose cyclophosphamide (CTX). Their generation, however, was abrogated by low-dose CTX and irradiation at the early stage of their development. Spleen cells from PC-bearing mice treated with high-dose CTX were enhanced in their effector activity, suggesting the co-existence of CTX-sensitive suppressor cells. The suppressor cells could be demonstrated in spleens of mice bearing a heterologous PC and were found also to be radiosensitive, non-adherent, Thy 1-positive T-cells. Their generation was blocked by treatment of mice with CTX during the early stage of PC development. These findings provide evidence for the occurrence of immune effector T-cells in mice with a growing PC. This immunity appears to be down-regulated by CTX-sensitive suppressor cells.

Animals↗
PubMed1984

Inhibition of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) activity in first- and second-trimester human pregnancy and the luteal phase using Epostane.

The effects of a competitive inhibitor of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) (Epostane, Sterling Winthrop, Guildford, England) on serum progesterone (P), estradiol (E2), and cortisol have been studied in three groups of pregnant women awaiting termination of pregnancy (5 to 8 weeks, 8 to 12 weeks, and 12 to 18 weeks of pregnancy) and 15 women in the luteal phase of the menstrual cycle. A single-dose randomized double-blind study was performed, each woman receiving a placebo, 50 mg of Epostane, or 100 mg of Epostane. In the pregnant group, there was a significant decline in the serum P concentration after both 50 mg and 100 mg of Epostane. The percentage fall increased with both drug dosage and advancing gestation. A similar fall in serum E2 was observed. Both of these effects were temporary. In the luteal phase group, a significant decline in serum P was observed after 100 mg of Epostane, but the serum E2 was not significantly different from the pretreatment concentration. Serum cortisol did not differ significantly from control values. These findings suggest that Epostane is an effective inhibitor of placental and ovarian 3 beta-HSD, which may have a role as an interceptive agent.

3-Hydroxysteroid Dehydrogenases↗
PubMed1984

The influence of spontaneous and induced labour on the rise in prostaglandins at amniotomy.

Maternal peripheral plasma levels of 13,14-dihydro-15-keto-prostaglandin F (PGFM) were measured immediately before and 5 min after amniotomy. Three groups of women were studied: women in late pregnancy; women in spontaneous labour; and women who had received intravaginal prostaglandin E2 (PGE2) pessary. There was no significant difference in the magnitude of the rise in PGFM after amniotomy in late pregnancy or during spontaneous labour suggesting that labour has no influence on the release of prostaglandin F2 alpha (PGF2 alpha) induced by artificial rupture of the fetal membranes. However, local administration of PGE2 before amniotomy caused a greater rise in PGFM suggesting that PGE2 can influence the release and/or metabolism of PGF2 alpha.

Adult↗