Search PubMed⌕ Search

Biomedical subjects

R Anderson

Publications and source records attributed to R Anderson.

At least 325 records · Page 18Linked to original sources
PubMed1994

Chronic inhalation and biopersistence of refractory ceramic fiber in rats and hamsters.

Lifetime "nose-only" inhalation studies were conducted in rats using four types of refractory ceramic fibers (FCF), 1 micron in diameter x 22 to 26 microns length: High Purity, Kaolin, Zirconia, and After-Service; and on hamsters using Kaolin RCF. For comparison, animals also were exposed to chrysotile fibers. Rats were exposed 6 hr/day, 5 days/week for 24 months to concentrations ranging between 3 and 30 mg/m3. Time- and dose-dependent lesions in the rat included the development of interstitial fibrosis, pleural fibrosis, pulmonary tumors, and mesothelioma. Exposure to 3, 9 or 16 mg/m3 produced no excess lung tumors; no fibrosis was seen at 3 mg/m3. A significant increase in lung tumors and interstitial fibrosis was observed at 30 mg/m3. A single mesothelioma was observed in rats exposed to 9 mg/m3, while two occurred at 30 mg/m3. Hamsters were similarly exposed to 30 mg/m3 Kaolin RCF for 18 months; no lung tumors were induced, but pulmonary and pleural fibrosis were observed and there was a 42% incidence of mesothelioma. Multiple interim sacrifices together with recovery animals allowed detailed assessment of the lung burden of RCF, which was found to be dose related and, at the high doses, exceeded 10(5) fibers/mg of dry lung. During the various recovery periods there was a clear reduction in fiber burden. Mathematical modeling of these data for deposition, clearance, and retention and for species is currently underway.

Administration, Inhalation↗
PubMed1994

Comparison of the composition and opsonic activities of imported and South African-manufactured intravenous and intramuscular immunoglobulin preparations.

We compared the composition and opsonic activities for two common microbial pathogens (Staphylococcus aureus and Streptococcus pyogenes) of various imported intravenous (IV) (Sandoglobulin, Octagam and Gammagard) and intramuscular (IM) (Beriglobin and Globuman Berna) immunoglobulin (Ig) preparations with those of the corresponding locally manufactured products, Polygam (IV) and Intragam (IM). When tested at equivalent concentrations (1 g/100 ml) the total IgG and IgG subclass concentrations of the various IV and IM preparations were similar. All the test preparations (IV and IM) possessed similar opsonic activity for S. aureus and S. pyogenes. These findings demonstrate that, in respect of IgG content and protective biological activity, Intragam and Polygam, the locally manufactured IM and IV Ig preparations, respectively, compared extremely favourably with the corresponding imported products.

Humans↗
PubMed1994

A practice-based information system for multi-disciplinary care of chronically ill patients: what information do we need? The Community Care Coordination Network Database Group.

Primary care physicians provide longitudinal care for chronically ill individuals in concert with many other community-based disciplines. The care management of these individuals requires data not traditionally collected during the care of well, or acutely ill individuals. These data not only concern the patient, in the form of patient functional status, mental status and affect, but also pertain to the caregiver, home environment, and the formal community health and social service system. The goal of the Community Care Coordination Network is to build a primary care-based information system to share patient data and communicate patient related information among the community-based multi-disciplinary teams. One objective of the Community Care Coordination Network is to create a Community Care Database for chronically ill individuals by identifying those data elements necessary for efficient multi-disciplinary care.

Chronic Disease↗
PubMed1994

[Selective vascular occlusion by repetitive short laser pulse].

The occlusion of arterioles and venules (30 microns in diameter) by means of repeated dye laser pulses (577 nm, 160 microseconds, 0.5 Hz) was studied in the hamster cheek pouch model. Microscopically visible changes during and after irradiation were recorded and monitored by a video system. The energy necessary per pulse for vessel occlusion with a single pulse (arterioles 5 J/cm2, venules 3.5 J/cm2) can be lowered more than 50% with 100 pulses (1.8 J/cm2, 1.2 J/cm2). Rupture of vessels, which regularly occurs with a single pulse, can be totally avoided with 100 repetitive laser pulses. Investigations of the temperature dependence of the occlusion rate of arterioles showed different interaction mechanisms with one pulse and 100 pulses (mechanical and thermal respectively). Light and electron microscopic investigations supported this concept of selective occlusion using repeated short laser pulses. Possible clinical applications are portwine stains of the eyelid, neovascularisation on the cornea and subretinal neovascularisation.

Animals↗
PubMed1994

In vitro activity of readily available household materials against HIV-1: is bleach enough?

This report describes experiments assessing the effectiveness against HIV of potential disinfecting agents that are commonly available to IDU when they are sharing syringes. We exposed cell-free HIV, HIV-infected cells, and HIV-infected blood containing known quantities of HIV to household cleaning agents, alcohols, peroxide, and highly acidic materials for 1 min, in order to examine the effects of these materials on the infectivity of the HIV. Undiluted liquid laundry bleach and dilute liquid dish detergent reduced the number of culturable HIV to an undetectable level under the experimental conditions used. Diluted bleach was not completely effective. Other potential disinfecting agents, including ethanol, isopropyl alcohol, and hydrogen peroxide, were unable to disinfect high numbers of HIV-infected cells or infected blood. Liquid dish detergent warrants further study as a possible acceptable alternative to bleach. Our data provide support for recommendations to IDU that they disinfect shared syringes every time between users with full-strength liquid laundry bleach to reduce their risk of acquiring or transmitting HIV. When bleach is not available, liquid dish detergent or other available disinfecting agents such as rubbing alcohol, hydrogen peroxide, or high alcohol content beverages are more effective than water at disinfecting HIV, recognizing that these materials are less effective than bleach. Although these materials are effective, they should not be viewed as a substitute for decreased sharing of injection equipment by IDU, or increased availability of sterile needles and syringes.

1-Propanol↗
PubMed1993

Clinical manifestations of AIDS in the era of pneumocystis prophylaxis. Multicenter AIDS Cohort Study.

BACKGROUND: Among patients infected with human immunodeficiency virus type 1 (HIV-1), early and widespread use of prophylactic regimens against Pneumocystis carinii is changing the pattern of illnesses related to the acquired immunodeficiency syndrome (AIDS). METHODS: We conducted a subcohort analysis of 844 men with AIDS (87 percent of whom have since died) from a prospectively followed cohort of 2592 HIV-1-infected homosexual men. RESULTS: A total of 138 men received prophylaxis before the diagnosis of AIDS, but 39 (28 percent) nevertheless had P. carinii pneumonia at some time. Only four illnesses occurred more frequently in men who received P. carinii prophylaxis before the onset of AIDS: Mycobacterium avium complex disease, which developed in 33.4 percent, as compared with 17.3 percent of the 706 men who did not receive early prophylaxis; wasting syndrome (18.4 percent vs. 6.4 percent); cytomegalovirus disease (44.9 percent vs. 24.8 percent); and esophageal candidiasis (21.3 percent vs. 12.8 percent). Collectively, these four diseases accounted for the initial AIDS-related illness in 42.7 percent of those who received prophylaxis before the onset of AIDS, as compared with 10.7 percent of those who did not. During the three six-month periods before the diagnosis of AIDS (0 to 6, > 6 to 12, and > 12 to 18 months), the geometric mean CD4+ cell counts were 48, 87, and 147 per cubic millimeter, respectively, in men who received prophylaxis against P. carinii, as compared with 118, 211, and 279 per cubic millimeter in those who did not. CONCLUSIONS: M. avium complex disease, esophageal candidiasis, wasting syndrome, and cytomegalovirus disease are more common in HIV-infected patients who have received prophylaxis against P. carinii than in those who have not. Prophylaxis may delay the first AIDS illness for 6 to 12 months.

AIDS-Related Opportunistic Infections↗
PubMed1993

Clofazimine and B669 inhibit the proliferative responses and Na+, K(+)-adenosine triphosphatase activity of human lymphocytes by a lysophospholipid-dependent mechanism.

The relationship between the phospholipase-stimulating and immunosuppressive properties of the riminophenazine anti-mycobacterial agent clofazimine and its experimental analogue, B669, has been investigated in vitro. At concentrations of 0.6 microM and upwards, both riminophenazines, particularly B669, caused dose-related inhibition of mitogen- and alloantigen-stimulated uptake of tritiated thymidine by human mononuclear leucocytes (MNL), while in short-term assays both agents increased the release of lysophosphatidylcholine (LPC) and arachidonic acid from these cells. Arachidonate per se at a concentration of 20 microM did not affect mitogen-activated lymphocyte proliferation, while cyclooxygenase and 5'-lipoxygenase inhibitors, as well as water- and lipid-soluble oxidant-scavengers and anti-oxidant enzymes, failed to protect the cells against the anti-proliferative effects of clofazimine and B669. However, LPC caused dose-related inhibition of lymphocyte proliferation. Moreover, co-incubation of NML with alpha-tocopherol (vitamin E), a lysophospholipid complex-forming agent, or with lysophospholipase, protected the cells against clofazimine and B669, as well as against LPC. Na+, K(+)-adenosine triphosphatase was identified as the primary target of riminophenazine/LPC-mediated inhibition of lymphocyte proliferation. Excessive release of anti-proliferative lysophospholipids during clofazimine or B669 treatment of mitogen- or antigen-activated lymphocytes is the probable biochemical mechanism of the immunosuppressive activity of these agents.

Anti-Infective Agents↗
PubMed1993

The association between prenatal care and birth weight among women exposed to cocaine in New York City.

OBJECTIVES: Although the association between antenatal cocaine use and adverse birth outcomes has been well documented, relatively little is known about interventions that may ameliorate these consequences. We therefore examined the relationship between prenatal care and birth weight among a population of prenatal cocaine users. DESIGN: Population-based retrospective analysis. PATIENTS: All single-gestation live births to white non-Hispanic, black non-Hispanic, and Hispanic residents of New York City who gave birth between 1988 and 1990 with a positive indication for cocaine recorded on birth certificates (N = 7923). MAIN OUTCOME MEASURES: We contrasted mean birth weight and rates of low birth weight (< 2500 g) among cocaine users with one to three prenatal care visits, four or more visits, and unknown numbers of visits with users who reported no prenatal care. We used ordinary least squares and logistic regression to control for age, parity, smoking, alcohol, other drugs, weight gain, prepregnancy weight, employment, marital status, participation in the Supplemental Food Program for Women, Infants and Children, and method of finance. MAIN RESULTS: Adjusted odds ratios of low birth weight for cocaine users with four prenatal care visits or more as compared with those who had none were 0.51 for blacks (95% confidence interval [CI], 0.44 to 0.59), 0.39 for whites (95% CI, 0.23 to 0.66), and 0.37 for Hispanics (95% CI, 0.28 to 0.48). Adjusted mean birth weight differences between users with four visits or more and those with none were 262 g for blacks (P < .001), 247 g for whites (P < .001), and 317 g for Hispanics (P < .001). CONCLUSIONS: The receipt of prenatal care among cocaine users is associated with significant improvements in birth weight. Enrollment of cocaine users in prenatal care may be an effective start to a more comprehensive approach to this problem.

Adult↗
PubMed1993

Epidemiologic analysis of Kaposi's sarcoma as an early and later AIDS outcome in homosexual men.

The authors separately studied the epidemiology (risk and risk factors) of Kaposi's sarcoma occurring as an initial acquired immunodeficiency syndrome (AIDS) outcome (early Kaposi's sarcoma) and later after a different initial AIDS outcome (later Kaposi's sarcoma) in a cohort of 2,591 human immunodeficiency virus type 1-infected gay men of the Multicenter AIDS Cohort Study between 1984 and 1992. Among 844 AIDS cases, 202 presented with early Kaposi's sarcoma, 101 subsequently developed later Kaposi's sarcoma, and 541 were not diagnosed with Kaposi's sarcoma. Overall, 37.4% of AIDS cases were diagnosed with Kaposi's sarcoma prior to death. Kaposi's sarcoma diagnosed on the skin was significantly more common with early Kaposi's sarcoma (77.3%) than with later Kaposi's sarcoma (65.1%). Men presenting with an AIDS outcome other than Kaposi's sarcoma were at high risk for later Kaposi's sarcoma. Later Kaposi's sarcoma onset in men with a previous AIDS outcome was associated with the following characteristics: 1) lower immune status prior to AIDS and 2) longer post-AIDS survival. A Kaposi's sarcoma diagnosis in a man with a previous AIDS illness approximately doubled the risk (hazard) for death. Histories of urethral gonorrhea and scabies prior to study entry were more common in early Kaposi's sarcoma cases than in later Kaposi's sarcoma cases. However, self-reported sexual activity at study entry and prior to AIDS onset was highest in the later Kaposi's sarcoma group. In this cohort, cigarette smoking had a protective association against all Kaposi's sarcoma in univariate and multivariate models. Only 21.0% of the later Kaposi's sarcoma and 25.0% of the early Kaposi's sarcoma men smoked at least one-half pack of cigarettes daily at study entry compared with 33.8% of non-Kaposi's sarcoma and 35.5% of seroprevalent men still AIDS free. The reasons for this surprising association are unclear. However, other evidence which documents that habitual smoking alters the immune system (and possibly cytokine levels) in ways that could perhaps influence Kaposi's sarcoma pathogenesis should be considered.

Acquired Immunodeficiency Syndrome↗
PubMed1993

AIDS: trends, predictions, controversy.

One of the persistent controversies that surfaces in the media about AIDS is whether the heterosexual population is at risk. The latest projections provide an emphatic affirmative.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Follow-up of angle-closure glaucoma suspects.

One hundred twenty-nine patients thought to be at risk for developing angle-closure glaucoma underwent a baseline examination, which included gonioscopy, refraction, anterior chamber pachymetry, ultrasound biometry, and an angle-closure provocative test. Patients were then followed up with no treatment. Mean follow-up was 2.7 years with a range up to six years. Twenty-five patients developed angle closure in at least one eye during the follow-up period, but in most (17 of the 25 patients), the angle closure was nonacute (that is, no clinical signs or symptoms and no increase in intraocular pressure). None of the test factors studied showed a high sensitivity or positive predictive accuracy in detecting the eyes that later developed angle closure.

Adult↗
PubMed1993

The riminophenazine agents clofazimine and B669 inhibit the proliferation of cancer cell lines in vitro by phospholipase A2-mediated oxidative and nonoxidative mechanisms.

Clofazimine, a riminophenazine antimicrobial agent, and its analogue B669 were investigated for their effects on FaDu cells, a human squamous carcinoma cell line. These agents, at concentrations within the therapeutic range (0.25-2 micrograms/ml), caused a dose-dependent tumor cell cytotoxicosis which was greatly enhanced in the presence of human neutrophils. The neutrophil-mediated increment in tumoricidal activity, but not the direct antitumor effects of the drugs per se, was inhibited by catalase. The effects of these drugs on three more cell carcinoma lines as well as on two primary cultures and a noncarcinoma cell line were also investigated and compared with the activity of the standard antitumor chemotherapeutic agents bleomycin, cisplatin, and methotrexate. All seven cultures were sensitive to clofazimine and B669 compared to six that were sensitive to cisplatin, three that were sensitive to bleomycin, and one that was sensitive to methotrexate. The treatment of FaDu cells with clofazimine and B669 was associated with enhanced activity of phospholipase A2, as evidenced by increased release of radiolabeled arachidonate and lysophosphatidylcholine from membrane phospholipids. Inhibitors of arachidonic acid metabolism, protein kinase C inhibitors, as well as water and lipid soluble antioxidants failed to protect the cells against the cytotoxic activity of clofazimine and B669. However, alpha-tocopherol, a lysophospholipid-complexing agent, completely blocked the antiproliferative effects of the riminophenazines and also protected the cells against the direct cytotoxic effect of lysophosphatidylcholine, while the lysophospholipid-neutralizing enzyme lysophospholipase protected against the riminophenazines. These observations demonstrate that the tumoricidal properties of clofazimine and B669 are probably due to increases in the lysophospholipid content of cell membranes.

Animals↗
PubMed1993

Mutation analysis and haplotype correlation for 139 cystic fibrosis patients from the Nebraska Regional Cystic Fibrosis Center.

Cystic fibrosis (CF) is the most common autosomal recessive disorder in Caucasian populations with an approximate frequency of one in 2,500 live births and a carrier frequency of one in 25. We studied 400 individuals seen at The Nebraska Regional Cystic Fibrosis Center that included 139 CF patients, 206 parents, and 55 unaffected siblings to determine the frequency of the delta F508, R117H, G542X, S549R/N, G551D, R553X, R560T, and W1282X mutations. In addition, we determined haplotypes on each of these individual's chromosomes using four markers that included XV-2c, KM-19, pMP6d.9, and G2. Results from this study showed that the delta F508 mutation was present in 70% of CF chromosomes. Of the 139 CF patients 74 (53%) were homozygous for the delta F508 deletion, 47 (34%) were heterozygous for the delta F508 deletion and an unknown mutation, and 18 (13%) carried two unknown mutations. Four additional mutations were also found in our population and included G542X (6%), G551D (5%), R553X (4%), and R560T (1%). One patient was documented to be a compound heterozygote for G542X/G551D. A polymorphism, F508C, that has previously been reported in several families was also present in our study. The most common haplotype associated with the delta F508 deletion in our CF patients was the E haplotype (CF Consortium B) while other mutations were associated with a variety of haplotypes.

Base Sequence↗
PubMed1993

3T3 cell integration and differentiative potential during limb development in the mouse.

In this study we have investigated the ability of embryonic mouse limb cells to induce the differentiation of 3T3 cells both in vivo and in vitro. Using the exo utero surgical technique we introduced labeled 3T3 cells into the embryonic mouse limb and monitored their subsequent development. We found no indication that the normal pattern of tissue differentiation was perturbed; rather we observed that 3T3 cells were closely associated with a variety of limb mesodermal tissues which include muscle, tendon, and ligament. In very rare instances did we observe 3T3 cells associated with cartilage. To further investigate the differentiative potential of 3T3 cells we cocultured labeled 3T3 cells with limb cells under conditions that favored either cartilage or muscle differentiation. The results from these experiments suggest that 3T3 cells avoid regions of chondrogenesis and rarely participate in myotube formation. We conclude that 3T3 cells are not responding to differentiation signals present in the developing limb, but rather are responding to signals involved in growth and tissue morphogenesis.

3T3 Cells↗
PubMed1993

Chronic inhalation toxicity of size-separated glass fibers in Fischer 344 rats.

This study was initiated to determine the chronic biological effects in Fisher 344 rats of inhaled size-separated respirable fractions of fibrous glass (FG) having compositions representative of common building insulation wools. Rats were exposed using nose-only inhalation chambers, 6 hr/day, 5 days/week, for 24 months to three concentrations (3, 16, and 30 mg/m3) of two different compositions of FG (designated MMVF 10 and MMVF 11), or to filtered air (negative control). Fibrous glass findings were compared to those from a concurrent inhalation study of chrysotile asbestos and refractory ceramic fiber (RCF). The FGs used in this study were size selected to be largely respirable in the rat and the aerosol generation technique did not alter the dimensions of the fibers. Interim euthanizations took place at 3- to 6-month intervals to monitor progression of pulmonary changes. Fibers were recovered from digested lung tissue for determination of changes in fiber number and morphology. In animals exposed to 30 mg/m3 of MMVF 10 or MMVF 11, 4.2 +/- 0.9 x 10(5) and 6.4 +/- 3.1 x 10(5) fibers/mg dry lung tissue, respectively, were recovered after 24 months of exposure. Exposure to chrysotile asbestos (10 mg/m3) and to a lesser extent RCF (30 mg/m3) resulted in pulmonary fibrosis as well as mesothelioma and significant increases in lung tumors. FG exposure was associated with a nonspecific inflammatory response (macrophage response) in the lungs that did not appear to progress after 6-12 months of exposure. These cellular changes are reversible and are similar to the effects observed after inhalation of an inert dust. No lung fibrosis was observed in the FG-exposed animals. Further, FG exposure resulted in no mesotheliomas and no statistically significant increase in lung tumor incidence when compared to that of the negative control group. These findings, along with previous inhalation studies, suggest that respirable fibrous glass does not represent a significant hazard for fibrotic or neoplastic lung disease in humans.

Aerosols↗