Search PubMed⌕ Search

Biomedical subjects

M Roberts

Publications and source records attributed to M Roberts.

At least 217 records · Page 12Linked to original sources

Anaphylaxis and asthma in a scrimshander due to deer bone dust.

A boilermaker who engraved deer bone (scrimshaw) as his artistic vocation developed recurrent anaphylaxis while scraping deer bones. These bones has been boiled in NaClO and dried, leaving residual NaOH and altered deer protein. He had recurrent episodes of anaphylaxis when exposed to the bone dust. The anaphylaxis appears to be the result of exposure of traumatized skin to NaOH and antigen with sufficient absorption of antigen to result in anaphylaxis, although inhalation may have been contributory. The most severe, near fatal episode of anaphylaxis may have been worsened by captopril. The patient's reaction by prick test to protein extracted in buffered saline from the deer bones boiled in NaClO and NaOH but not to natural deer protein suggested IgE antibody against deer protein altered by boiling in alkali. The scrimshander is now working with deer bone after prophylactic therapy and control of exposure.

Anaphylaxis↗

Measuring the HIV epidemic: the Western Australian experience.

Previous discussion about sources of error in measuring the human immunodeficiency virus (HIV) epidemic has tended to emphasise errors which underestimated the number of HIV infected persons. Data are provided from Western Australia illustrating potential errors which may result in overestimating the size of the epidemic. Duplication of persons notified in more than one State and multiple notifications by doctors and laboratories of single cases may give rise to substantial errors in over-estimation.

Contact Tracing↗

America's best hospitals. Exclusive survey.

To identify the nation's best hospitals, U.S. news surveyed in 12 specialties from aids to urology. The survey yielded 57 different hospitals, many of which appear on more than one of the 12 specialty lists. The following hospitals, all of which found their way onto at least four of the lists, represent the cream of America's medical institutions.

Attitude of Health Personnel↗

Topoisomerase I activity associated with human immunodeficiency virus (HIV) particles and equine infectious anemia virus core.

In the present study, we found a topoisomerase I (topo I) activity in two strains of human immunodeficiency virus type 1 (HIV-1) and equine infectious anemia virus (EIAV) particles. The topo I activity was located in the EIAV cores and differed from the cellular topo I in its ionic requirements and response to ATP, indicating that these were two distinct forms of this enzyme. Topo I activity was removed from the viral lysates and viral cores by anti-topo I antiserum. The only protein recognized by this antiserum was an 11.5 kd protein in HIV lysate and 11 kd in EIAV lysate. We showed that the 11 kd protein recognized by the anti-topo I antiserum is the EIAV p11 nucleocapsid protein. Furthermore, purified topo I protein blocked the binding of the antibodies to the p11 protein and vice versa, purified p11 protein blocked the binding of these antibodies to the cellular topo I. These results suggest that the EIAV p11 nucleocapsid protein and the cellular topo I share similar epitopes.

Antibodies↗

Hydrogen ultrathin phase-encoded spectroscopy (HUPSPEC).

This paper describes a new clinical spectroscopy pulse program, hydrogen ultrathin phase-encoded spectroscopy. This sequence combines high spatial resolution with magnitude hydrogen spectroscopy. A linear volume is spatially frequency encoded with a conventional readout gradient and phase encoded spectrally by incrementing the timing of acquisition. The pulse sequence is implemented on a whole-body MRI scanner and supports several standard scanner options, including autoprescanning, offset of the center of field of view in the frequency-encoding direction, and oblique imaging. Some preliminary experimental experience is reported, demonstrating the possibility of observing the spectral linewidths of fat and water in marrow, and of observing the spectral linewidths of fat and water in marrow, and of observing multiline spectra. Combination of the technique with water suppression methods in a sequence called WASHUP is also discussed.

Adult↗

Role of bacterial and host factors in the pathogenesis of Shigella septicemia.

To determine the role of bacterial and host factors in the pathogenesis of shigellemia, blood and fecal Shigella isolates were compared for serum resistance and siderophore production, and shigellemic patients were examined for decreased serum bactericidal activity or increased serum transferrin saturation compared to control patients with non-bacteremic shigellosis. The majority of both blood (36/38) and fecal (36/48) Shigella isolates were sensitive to normal serum (greater than 2 log kill/60 min). Shigella dysenteriae type 1 strains were the most sensitive, and Shigella sonnei strains were the most resistant. Siderophore production was species- and serotype-dependent. Shigella dysenteriae type 1 produced only enterochelin; most Shigella flexneri expressed only aerobactin, and Shigella sonnei secreted both types of siderophores. No difference in siderophores was noted between blood and fecal strains within a given serotype. In contrast, shigellemic patients exhibited a 43-fold decrease in serum bactericidal activity and a two-fold increase in transferrin saturation compared to well-nourished control patients. These results indicate that the pathogenesis of Shigella septicemia is not related to serum resistance or siderophore production but may involve serum abnormalities associated with malnutrition.

Adolescent↗

Clinical and serologic follow-up of four children and five adults with bird-fancier's lung.

We report the clinical and serologic findings in four children and five adults with chronic avian hypersensitivity pneumonitis. All subjects were treated with corticosteroids and bird exposure was reduced or eliminated. After a variable period, ranging from 6 months to 10 years, their clinical and serologic findings were reassessed. In terms of symptomatology, chest findings, and pulmonary functions, all four children improved and four adults improved, whereas one adult had a progressive clinical deterioration, ultimately resulting in her death 5 years later. In terms of serologic data, precipitating antibody tended to persist, and antibody to avian antigens, as determined by ELISA, remained positive, although the titer declined. We conclude that, while serologic positivity remains, the prognosis for children and adults with chronic avian hypersensitivity pneumonitis is very good, provided that irreversible damage has not already occurred at the time of diagnosis.

Adult↗

Yersinia enterocolitica aroA mutants as carriers of the B subunit of the Escherichia coli heat-labile enterotoxin to the murine immune system.

Plasmid p5F which directs the expression of the Escherichia coli heat-labile enterotoxin B subunit (LT-B) from the ptac promoter was introduced into the attenuated Yersinia enterocolitica O:8 aroA mutant strain YAM.1. YAM.1 (p5F) expressed high levels of cell-associated and secreted LT-B in a stable fashion when grown on normal laboratory medium. The strain was used as a live oral vaccine in BALB/c mice and vaccinated mice developed high levels of gut-associated and systemic antibodies to both LT-B and the lipopolysaccharide (LPS) of the vaccine strain. Anti-LT-B and anti-LPS responses in the sera were predominantly of the IgG class whereas gut-associated antibodies were predominantly IgA. ELISPOT assays carried out on selected tissues prepared from vaccinated mice showed significant numbers of cells synthesising IgG and IgA antibodies to LT-B. These results show that Y. enterocolitica aroA mutants can be used effectively as carriers of heterologous antigens to the murine immune system.

Animals↗

Resistance and allergy to recombinant human insulin.

Insulin allergy and antibody-mediated resistance may complicate therapy with animal insulins. We describe a 53-year-old man manifesting both resistance and persistent systemic allergy despite treatment with recombinant human insulin. Insulin resistance and symptoms of allergy appeared in this patient several months after initiating therapy with mixed beef-pork insulin, as is often the case. Symptoms initially improved, but persisted, and then worsened again, despite continuous human insulin therapy. Total insulin-binding capacity by Scatchard analysis, high plasma insulin-binding capacity, and specific anti-insulin antibody levels were consistent with an immunologic form of insulin resistance. Glucocorticoid therapy was required both to reduce allergic findings and to restore glycemic control. Although recently available human insulins may be less immunogenic than animal forms, immune responses to exogenous human insulin still may pose significant clinical problems.

Adult↗

Dental caries experience in schoolchildren in fluoridated and non-fluoridated communities in Western Australia.

A cross-sectional survey was undertaken in 1987 to measure the difference in caries experience in schoolchildren between a fluoridated (0.8 mg/L F-) and a non-fluoridated region (0.1-0.4 mg/L F-). 3436 children aged 5-15 yr were examined. Children in the non-fluoridated region had a higher caries experience than those in the fluoridated region. Mean differences were 1.06 dfs (95% CI = 0.66 to 1.47, P less than 0.001) and 0.48 DFS (95% CI = 0.23 to 0.72, P less than 0.001). After adjusting for potential confounding factors (fluoride tablet consumption, socioeconomic status, number of fissure-sealed surfaces, and mobility between regions) the relative risk of not being caries-free in the non-fluoridated region compared with the fluoridated region was 1.43 (95% CI = 1.21-1.70, P less than 0.0001) for the primary dentition and 1.39 (95% CI = 1.18-1.63, P less than 0.0001) for the permanent dentition.

Adolescent↗

Construction and characterization in vivo of Bordetella pertussis aroA mutants.

A DNA fragment encoding a kanamycin resistance determinant was used to insertionally inactivate the cloned aroA gene of Bordetella pertussis in Escherichia coli K-12, and a conjugative shuttle vector system based on the suicide vector pRTP1 was used to deliver the mutations from E. coli back into B. pertussis CN2992FS and BP1. The aroA mutation was introduced by allelic exchange into the chromosome of B. pertussis, resulting in otherwise isogenic parental and aroA mutant pairs. The B. pertussis aroA mutants grew well on laboratory medium supplemented with aromatic compounds but failed to grow on unsupplemented medium. The B. pertussis aroA mutants expressed the normal B. pertussis extracellular, virulence-associated proteins; inactivated, whole-cell vaccines prepared from the mutants protected mice as efficiently as vaccines made from the parent strains against intracerebral challenge with the virulent B. pertussis 18323. Live B. pertussis aroA bacteria inefficiently colonized the lungs of NIH/S mice after they were challenged with aerosol, unlike the wild-type B. pertussis organism. Mice exposed to three separate aerosols of live B. pertussis aroA bacteria were protected against lung colonization after being exposed to an aerosol containing the virulent parental B. pertussis strain. High-level antibodies against B. pertussis rapidly appeared in the sera of mice immunized by aerosol with the B. pertussis aroA strains and challenged with the virulent parent.

Aerosols↗

The momentum of human behavior in a natural setting.

Adults with mental retardation in a group home received popcorn or coffee reinforcers for sorting plastic dinnerware. In Part 1 of the experiment, reinforcers were dispensed according to a variable-interval 60-s schedule for sorting dinnerware of one color and according to a variable-interval 240-s schedule for sorting dinnerware of a different color in successive components of a multiple schedule. Sorting rates were similar in baseline, but when a video program was shown concurrently, sorting of dinnerware was more resistant to distraction when correlated with a higher rate of reinforcement. In Part 2 of the experiment, popcorn or coffee reinforcers were contingent upon sorting both colors of dinnerware according to variable-interval 60-s schedules, but additional reinforcers were given independently of sorting according to a variable-time 30-s schedule during one dinnerware-color component. Baseline sorting rate was lower but resistance to distraction by the video program was greater in the component with additional variable-time reinforcers. These results demonstrate that resistance to distraction depends on the rate of reinforcers obtained in the presence of component stimuli but is independent of baseline response rates and response-reinforcer contingencies. Moreover, these results are similar to those obtained in laboratory studies with pigeons, demonstrating that the determination of resistance to change by stimulus-reinforcer relations is not confined to controlled laboratory settings or unique to the pigeon.

Journal Article↗

When AIDS comes home.

Without loosening its grip on urban centers, AIDS is becoming more common in small-town and rural Texas. As a result, all hospitals face serious implications.

Acquired Immunodeficiency Syndrome↗

Fracture strength of Class I versus Class II restored premolars tested at the marginal ridge. 2. Cavosurface bonding and cavosurface plus internal enamel bonding.

The purpose of this study was to test the difference between the strength of the marginal ridge of extracted teeth with a Class I composite resin restoration and the strength of the marginal ridge of teeth with a Class II amalgam restoration with retention grooves. A statistically significant difference in fracture strengths was found among groups. No statistically significant difference was found among restored preparations, beveling technique, and restorative material. Statistically significant differences in fracture strength were found between the whole tooth group and treatment groups; between the whole tooth group and Class II amalgam restoration group; and between the unrestored tooth preparation group and all other tooth groups.

Acid Etching, Dental↗

Insulin allergy: re-evaluation after two decades.

We reevaluated IgE-mediated insulin allergy using sera obtained 16 to 21 years ago and, 1 and 5 years ago. All antibodies had specificity for human and bovine insulin. We reevaluated Prausnitz-Kustner reactivity after 15 years and the IgE antibody and cutaneous reactivity appeared unchanged. IgE-mediated insulin allergy appears to be declining.

Antibodies, Anti-Idiotypic↗

Phenotypic characteristics of dissociated mononuclear cells from rheumatoid synovial membrane.

The phenotypic characteristics of enzymatically dissociated synovial membrane mononuclear cells from 8 patients (14 samples) with rheumatoid arthritis (RA) were assessed by fluorescence activated flow cytometry and compared to peripheral blood (PB) mononuclear cells from 18 patients with RA and 14 normal controls. There was no significant difference between the percentage of CD4+ and CD8+ lymphocytes in synovial membrane compared to RA and normal PB. Double labelling experiments revealed similar percentages of CD4+ CDw29+ (helper-inducer) and CD4+ CD45R+ (suppressor-inducer) cells in RA and normal PB. In contrast, SM CD4+ CDw29+ cells were present in significantly higher proportions than in RA and normal PB (p less than 0.001). Conversely, synovial membrane CD4+ CD45R+ cells were present in significantly lower proportions than in RA and normal PB (p less than 0.001). A similar pattern of CDw29 and CD45R antigen expression was noted on CD8+ lymphocytes reflecting increased killer-effector (p less than 0.001) and decreased suppressor-effector (p less than 0.001) cells, respectively. Other experiments revealed a significant increase in the percentage of synovial membrane CD20+ cells (B lymphocytes) and HLA-DR+ cells compared to RA PB (p less than 0.02 and p less than 0.001) and normal PB (p less than 0.01 and p less than 0.005), and similar proportions of CD14+ cells (monocytes/macrophages). Our results suggest that RA synovial membrane contains populations of T and B lymphocytes that differ quantitatively and qualitatively from those in PB. These may account for some of the abnormalities in intraarticular humoral and cellular immune responses in patients with RA.

Antigens, CD↗