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Biomedical subjects

C Reed

Publications and source records attributed to C Reed.

At least 73 records · Page 4Linked to original sources
PubMed1990

The value of serum cryptococcal antigen in the diagnosis of cryptococcal infection in patients infected with the human immunodeficiency virus.

Serum cryptococcal antigen titres were measured in 828 HIV-infected patients with pyrexia, 69 of whom had meningism. Serum cryptococcal antigen was positive in 17 patients of whom 16 had meningism with cryptococcus isolated from their CSF. The other patient had no meningism, had no evidence of cryptococcal infection on repeated CSF examination and remains well. A positive serum cryptococcal antigen test was therefore valuable in the diagnosis of cryptococcal meningitis, although in all 16 patients meningism was present and a diagnostic lumbar puncture was therefore carried out. In our experience routine screening for serum cryptococcal antigen did not predict patients who subsequently developed cryptococcal meningitis.

Amphotericin B↗
PubMed1989

Resistance to drugs associated with the multidrug resistance phenotype following selection with high-concentration methotrexate.

To study patterns of resistance at extreme but nevertheless clinically relevant drug concentrations, we developed a series of methotrexate-selected CCRF-CEM sublines, all of which were highly resistant to this antifolate (relative resistance, 10(2)- to greater than 10(5)-fold). The least methotrexate-resistant subline was completely sensitive to drugs associated with the multidrug resistance phenotype. However, more highly methotrexate-resistant sublines were significantly cross-resistant to vincristine, vinblastine, and dactinomycin (maximum relative resistance, 40-fold). These sublines were not cross-resistant to doxorubicin, daunorubicin, and teniposide. Regression analysis indicated that relative resistance to methotrexate was correlated with relative resistance to vincristine (r = 0.96) and vinblastine (r = 0.99). Such cross-resistance in highly methotrexate-resistant cells may have important clinical implications.

Antineoplastic Agents↗
PubMed1989

Haptic integration of object properties: texture, hardness, and planar contour.

Planar objects varying in shape, texture, and hardness were classified under haptic exploration. Classes were defined by values on one dimension, or redundantly, by two or three dimensions. Response times and exploratory procedures (Lederman & Klatzky, 1987) were recorded. Experiment 1 showed that a second dimension speeded responses for all combinations (redundancy gain), but a third dimension produced no further effect. In Experiments 2 and 3, classification trials began with two redundant dimensions, and subsequently one was withdrawn (held constant). When texture and hardness varied redundantly, withdrawal of either increased response time--even when subjects were initially instructed to focus on one dimension. Joint exploration for texture and hardness dominated whenever the two varied redundantly and persisted despite withdrawal. Redundancy gains (Experiment 1), but not substantial withdrawal effects (Experiments 2 and 3), were observed for combinations of texture or hardness with planar contour, indicating less integration than between substance dimensions. Compatibility of exploratory procedures appears to constrain dimensional integration.

Attention↗
PubMed1989

The bacteriology of chronic venous ulcers treated with occlusive hydrocolloid dressings.

The bacterial flora of chronic venous ulcers treated with an occlusive hydrocolloid dressing were studied over a period of 8 weeks. A novel exudate sampling method was used in an attempt to isolate anaerobic bacteria. The flora was generally stable. Once a species was present, it remained with the exception of Pseudomonas, which appeared to be inhibited by the dressing. Twelve out of 20 ulcers contained anaerobic bacteria and healing did not appear to be impaired by the presence of any particular species of bacteria.

Aged↗
PubMed1989

Capillary blood glucose monitor. Evaluation in a newborn nursery.

The performance of a rapid capillary blood glucose monitor, the Glucoscan 2000, was evaluated in a neonatal patient population by comparison with a reference method on 283 paired patient samples. The median glucose was 56 mg/dL (3.1 mmol/L). The slope of the regression line was .93 with a correlation coefficient r of .82. The average error in Glucoscan values at low, intermediate and high glucose ranges was 43%, 20% and 12% respectively. Precision analysis by replicate determinations also showed an increased coefficient of variation, 7.4%, at low glucose values.

Blood Chemical Analysis↗
PubMed1989

Comparison of cyclophosphamide and diaziquone in a retinoblastoma xenograft model.

The benefits and optimal applications of chemotherapy in the management of retinoblastoma remain to be defined. There are major obstacles to its further study in the clinical setting. A xenograft model of human retinoblastoma heterotransplanted directly into the anterior chamber of the nude mouse eye has been adapted for evaluation of therapeutic efficacy. Cyclophosphamide, the most effective conventional drug, and diaziquone, an experimental agent, both produced documented and comparable responses in each of four xenograft cell lines. There was no evidence of rapidly emerging drug resistance or cross-resistance between two agents when sequential chemotherapy courses were given. Diaziquone is an effective chemotherapeutic agent for retinoblastoma in the xenograft model, and may have applications in clinical management.

Animals↗
PubMed1989

Visceral leishmaniasis (kala azar) in a patient with AIDS.

A patient with HIV infection presented with multiple cutaneous Kaposi's sarcomata. Biopsy of one of these showed the presence of amastigotes within an otherwise typical Kaposi's sarcoma. Further investigations proved the patient to have visceral leishmaniasis (kala azar). Visceral leishmaniasis has been reported in HIV infection but it is rare and this presentation is unique. The patient made a good response to a prolonged course of treatment with sodium stibogluconate and allopurinol.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Increased oxidation of uroporphyrinogen by an inducible liver microsomal system. Possible relevance to drug-induced uroporphyria.

1. The hypothesis that uroporphyria-inducing drugs stimulate the oxidation of uroporphyrinogen by a microsomal NADPH-dependent mechanism was tested. 2. 3,4,3',4'-Tetrachlorobiphenyl, a very effective inducer of uroporphyria in chick-embryo hepatocyte cultures, stimulates the NADPH-dependent oxidation of uroporphyrinogen by chick-embryo microsomal fraction in vitro. 3. Two different actions of 3,4,3',4'-tetrachlorobiphenyl are apparently required for this effect: (a) induction of a microsomal system by treatment in vivo and (b) interaction with the induced microsomal fraction in vitro, producing an oxidizing species. 4. The analogue 2,4,2',4'-tetrachlorobiphenyl is relatively ineffective in both the production of porphyria in culture and the stimulation of porphyrinogen oxidation in vitro. 5. Rat hepatocytes do not develop uroporphyria when treated with polychlorinated biphenyls in culture, yet they respond to these drugs with typical induction of cytochrome P-448-dependent drug metabolism. 6. These data provide support for the hypothesis of an increased oxidation of uroporphyrinogen in drug-induced uroporphyria, but also suggest that induction of cytochrome P-448 is not the only factor involved. 7. Both I and III isomers of uroporphyrin and heptacarboxylate porphyrin accumulate when chicken hepatocytes are made uroporphyric by drugs; treatment with desferrioxamine causes a marked decrease in both isomers, suggesting that iron may be involved in the accumulation of both.

Aminolevulinic Acid↗
PubMed1988

Isolation and partial characterisation of a 26 kilodalton antigen from Plasmodium falciparum recognised by an inhibitory monoclonal antibody.

A 26 kDa protein, present in trophozoites and schizonts of Plasmodium falciparum, has been identified as the target of a monoclonal antibody that weakly inhibits parasite growth in vitro. The antigen has been purified to homogeneity by immuno-affinity chromatography and electrophoresis. The sequence of 19 amino acids at the N-terminus of the protein has been determined.

Amino Acid Sequence↗
PubMed1987

Non-cytocidal natural variants of human immunodeficiency virus isolated from AIDS patients with neurological disorders.

To understand the mechanism of HIV-mediated neuropathology five viral isolates were obtained from four AIDS cases with central nervous system manifestations as the primary involvement. The isolates were identified as HIVs by antigenic cross-reactivity and nucleic acid hybridizations to HIV-specific antibodies and DNA probes. The replication and cytopathic properties of these isolates were studied and compared with lymphadenopathy-associated virus (HIVLAV). All isolates had replication competence equivalent to LAV, but four isolates did not kill T4 (CD-4) cells. This isolation of non-cytocidal natural variants of HIV raises the possibility that in some AIDS cases the neurological disorders might be due to HIV variants that are non-cytocidal to T4 cells. The results also indicate that virus replication and cytotoxicity are not always concordant functions in HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Activated K-ras and N-ras oncogenes in primary renal mesenchymal tumors induced in F344 rats by methyl(methoxymethyl)nitrosamine.

Administration of methyl(methoxymethyl)nitrosamine to newborn Fischer 344 rats results in the preferential induction of renal tumors arising from the mesenchymal component of the kidney. DNA from a significant proportion of these tumors was capable of transforming NIH/3T3 cells. This report describes the renal tumor model, the detection of two different ras transforming genes in the kidney tumors (the N-ras oncogene in 1 and K-ras oncogene in 10 kidney tumors) and the characterization of DNA sequences specifying the transformed phenotype.

Animals↗
PubMed1985

Intrinsic laryngeal muscle activity in a spastic dysphonia patient.

EMG activity from four intrinsic laryngeal muscles (thyroarytenoid, posterior cricoarytenoid, interarytenoid, and cricothyroid) was obtained from one female spastic dysphonia patient while she performed a variety of speech and nonspeech tasks. These tasks were performed before and during a period of temporary unilateral laryngeal muscle paralysis. In the nonparalyzed condition, adductory muscle activity showed intermittent sudden increases that coincided with momentary voice arrests. These muscle patterns and accompanying voice interruptions were not present either when speech was produced in falsetto register or at anytime during the paralysis condition. The data suggest that individuals with this type of spastic dysphonia have normal morphology of recurrent laryngeal nerves and intrinsic laryngeal muscles, which means that the triggering mechanism(s) for spastic dysphonia symptoms must be located at some point neurologically upstream from the larynx.

Combined Modality Therapy↗
PubMed1985

A comparison of intranasal and oral flunisolide in the therapy of allergic rhinitis. Evidence for a topical effect.

Intranasal flunisolide is an effective treatment for allergic rhinitis. Flunisolide has high bioavailability when administered to normal subjects (50% of an intranasal dose reaches the systemic circulation) with minimal systemic effects. Bioavailability in patients with active rhinitis averages 62.4 +/- 15.7%. The oral dose bioequivalent to 100 micrograms intranasally is 500 micrograms. To define the comparative trial and systemic effects of intranasal flunisolide in patients with active allergic rhinitis, a multicenter, randomized, double-blind, placebo-controlled study was conducted during the 1983 ragweed hayfever season. Ninety-nine patients with ragweed hayfever for greater than or equal to 2 years and positive prick skin tests to ragweed were randomly allocated to one of three treatment groups: 0 = oral flunisolide 500 micrograms b.i.d. and intranasal placebo b.i.d.; N = intranasal flunisolide 50 micrograms per nostril b.i.d. and oral placebo b.i.d.; P = intranasal and oral placebo b.i.d. Treatment continued for 4 weeks. Patients kept daily symptom scores. Patients were evaluated by a blinded observer every 2 weeks and were globally evaluated at the study's end. Data were analyzed for each center and pooled. There were no significant differences in symptom severity of sneezing, nasal congestion, and throat itch in the 0 (oral flunisolide) and P (placebo) groups. N (nasal flunisolide) was significantly more effective than O or P (P less than or equal to 0.005) for each symptom for at least one 2-week period. Global evaluation demonstrated control of overall hayfever severity for N (nasal flunisolide) but not for O (oral flunisolide). We conclude that the therapeutic efficacy of flunisolide is achieved by topical and not by systemic action.

Administration, Intranasal↗
PubMed1984

Assessment of tachyphylaxis following prolonged therapy of asthma with inhaled albuterol aerosol.

Controversy exists concerning possible tachyphylaxis of the acute bronchodilating effect of albuterol, especially with regard to the duration of its acute bronchodilating action. We evaluated 140 patients with bronchial asthma in a prospective double-blind controlled study of possible tachyphylaxis to albuterol aerosol as compared to isoproterenol aerosol. We demonstrated statistically significant tachyphylaxis with regard to duration of acute bronchodilating effect. We believe that this tachyphylaxis is not clinically significant because there was no tachyphylaxis with regard to peak bronchodilating effect and because the duration of bronchodilating effect remains significantly greater, both quantitatively and statistically, when compared to isoproterenol aerosol. Moreover, it appeared that most of the tachyphylaxis was present at four weeks of therapy. There was a small increment of tachyphylaxis after eight weeks of therapy, but no further increase in tachyphylaxis was demonstrated after 13 weeks of inhaled albuterol therapy. We therefore feel that clinically significant tachyphylaxis to inhaled albuterol aerosol must be quite unusual and that chronic therapy with inhaled albuterol aerosol is probably both safe and efficacious for bronchospastic disorders.

Adolescent↗