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Biomedical subjects

M Roberts

Publications and source records attributed to M Roberts.

At least 235 records · Page 13Linked to original sources
PubMed1989

Motor vehicle driving among diabetics taking insulin and non-diabetics.

OBJECTIVE: To determine whether rates of road traffic accidents were higher in diabetics treated with insulin than in non-diabetic subjects. DESIGN: Controlled, five year retrospective survey. SETTING: Diabetic, dermatology, and gastroenterology outpatient clinics. PATIENTS: 596 Diabetics treated with insulin (354 drivers) aged 18-65 attending two clinics and 476 non-diabetic outpatients (302 drivers). MAIN OUTCOME MEASURES: Rates of accidents in diabetic and non-diabetic subjects. RESULTS: A self completed questionnaire was used to record age, sex, driving state, and rates of accidents and convictions for motoring offences among diabetic and non-diabetic volunteers. For the diabetic volunteers further information was obtained on treatment, experience of hypoglycaemia, and declaration of disability to the Driving and Vehicle Licensing Centre and their insurance company. Accident rates were similar (81 (23%) diabetic and 76 (25%) non-diabetic drivers had had accidents in the previous five years). A total of 103 diabetic drivers had recognised hypoglycaemic symptoms while driving during the previous year. Only 12 reported that hypoglycaemia had ever caused an accident. Overall, 249 had declared their diabetes to an insurance company. Of these, 107 had been required to pay an increased premium, but there was no excess of accidents in this group. CONCLUSIONS: Diabetic drivers treated with insulin and attending clinics have no more accidents than non-diabetic subjects and may be penalised unfairly by insurance companies.

Accidents, Traffic↗
PubMed1989

IgG antibody against formaldehyde human serum proteins: a comparison with other IgG antibodies against inhalant proteins and reactive chemicals.

Immune responses to formaldehyde (F) have been recorded for seven decades. More recently, sensitive assays for antibody against F-human serum albumin (HSA) have been reported. IgG antibody against F-HSA has been said to correlate with symptoms against F-HSA. We report on 61 serum samples analyzed for IgG antibodies against F-HSA. IgG antibodies against F-HSA were most prevalent in subjects who had received intravenous F. In no case (either presumed symptomatic to F or with IgG antibody against F-HSA) was there a correlation of serologic results with symptoms. We also reviewed inhalation disease caused by chemicals and proteins acting as immunogens and report that at this time there is no evidence that gaseous F meets the criteria for causation of inhalational IgG-mediated lung disease by clinical or serologic studies. Very high IgG antibody levels occur in respiratory immunologic inhalational disease, and the absence of these high IgG levels against F is strong evidence against F or F proteins being an inhalational antigen of significance.

Allergens↗
PubMed1989

Fluctuations of serum IgA and its subclasses in allergic bronchopulmonary aspergillosis.

Exacerbations of allergic bronchopulmonary aspergillosis (ABPA) are characterized by chest roentgenographic infiltrates, peripheral blood eosinophilia, and elevation of total serum IgE. Also elevated are serum immunoglobulin antibodies directed against Aspergillus fumigatus, IgE-Af, serum IgG-Af, and serum IgA-Af. We measured serum IgA-Af, IgA1-Af, and IgA2-Af by ELISA to determine whether elevations of IgA-Af occurred before or during an exacerbation (like IgG-Af) or after (like IgE-Af). Ten exacerbations of ABPA were studied in seven patients with an average of 10 serial sera per patient analyzed. We used an indirect amplified ELISA with Af initially sensitizing microtiter wells. A "serologic" rise of immunoglobulin Af was identified when optical densities were twice the baseline sera. Serum IgA-Af was elevated over baseline before (n = 5) and during (n = 1) the time of an exacerbation. Serum IgA1-Af was elevated over baseline before (n = 5) or at the time (n = 5) of an exacerbation in all 10 cases. Serum IgA2-Af was elevated before (n = 2) and during (n = 5) exacerbations. Analogous to total serum IgE and IgG-Af, these experiments demonstrate substantial elevations of serum IgA-Af, IgA2-Af, and particularly, IgA1-Af before or during exacerbations characterized by roentgenographic infiltrates. The data are consistent with a contributory role of IgA-Af in the pathogenesis of ABPA.

Adolescent↗
PubMed1989

Graves' disease: an analysis of thyroid hormone levels and hyperthyroid signs and symptoms.

PURPOSE: Assessment of disease severity for patients with hyperthyroidism involves clinical evaluation and laboratory testing. To determine if there is a correlation between symptoms and thyroid function test results, we prospectively studied hyperthyroid patients using a standardized symptom rating scale and serum thyroid function parameters. PATIENTS AND METHODS: We examined 25 patients with untreated, newly diagnosed Graves' disease using the Hyperthyroid Symptom Scale (HSS) and serum levels of thyroxine (T4), triiodothyronine (T3) relative insulin area (RIA), and estimates of free thyroxine index (FTI). In addition, we compared thyroid hormone levels with standard measures of depression and anxiety in these patients. RESULTS: When regression analyses controlling for age were performed, none of these symptom ratings were associated with FTI or T3 RIA. The HSS was correlated with goiter size and anxiety ratings and was inversely correlated with age. CONCLUSION: The present study suggests that there is no relationship between the clinical assessment of disease severity and serum levels of thyroid hormone in untreated Graves' disease.

Adult↗
PubMed1989

Alcohol, cigarette smoking and breast cancer.

The results of two case-control studies of breast cancer which included questions on exposure to tobacco and alcohol are reported. One study included 998 hospital cases and a like number of matched hospital controls while the other included 118 cases identified during mammographic screening and a like number of matched normal screenees. Both studies used the same questionnaires and the same methods to obtain information. The results with regard to cigarette smoking differed between the two studies. The hospital-based study showed a decreased risk of breast cancer with increasing amounts smoked (relative risk for 15 or more cigarettes per day was 0.82, 95% confidence interval 0.60-1.13) while the screening study showed an increased risk (relative risk for 15 or more cigarettes per day was 2.90, 95% confidence interval 1.16-7.25). Evidence is presented that both results may be attributable to bias in the selection of cases and controls. It is concluded that reliable results on the relationship between smoking and breast cancer are only likely to come from population-based studies. These studies, in general, have found no relationship. Neither study produced any hint of an association between alcohol consumption and breast cancer. From this, it appears that bias in subject selection may not be such a significant factor in interpretation of studies of alcohol and breast cancer as it is in studies of smoking and the disease. A number of other difficulties in the interpretation of studies of alcohol and breast cancer are considered, including the great variation in the amount of alcohol consumed. It is concluded that the assertion that alcohol is a risk factor for breast cancer remains unproven.

Adult↗
PubMed1989

Lack of cross-reactivity between IgE to salmon and protamine sulfate.

Immediate type-generalized reactions to protamine sulfate are uncommon but may be fatal. The mechanisms of severe or fatal reactions are unknown in most cases. One theory is that contaminating fish (salmon) proteins present in protamine solutions induce anaphylaxis in salmon-sensitive subjects. A second hypothesis is that protamine interacts with anti-salmon IgE to cause anaphylaxis. We assessed these hypotheses by establishing an indirect amplified enzyme-linked immunosorbent assay (ELISA) for IgE to salmon. Sera obtained from two subjects anaphylactically sensitive to salmon demonstrated high binding to salmon that was not inhibited by preincubation of sera with 500 or 1000 micrograms of protamine or Aspergillus fumigatus. Serum from a patient who experienced anaphylactic shock from protamine was indistinguishable from control sera in the ELISA for IgE to salmon. Anti-protamine IgE could not be demonstrated in separate experiments. The assays prove that 1) serum IgE to salmon is not inhibited by protamine and 2) serum from a patient experiencing a severe reaction to protamine did not contain IgE to salmon or protamine. The experiments do not support the notion that there is cross-reactivity between IgE to salmon and protamine sulfate in the cases evaluated.

Anaphylaxis↗
PubMed1989

Inhibition of biological activities of the aerobactin receptor protein in rough strains of Escherichia coli by polyclonal antiserum raised against native protein.

The aerobactin iron-uptake system of plasmid ColV-K30, genetically isolated from other plasmid determinants by molecular cloning, was sufficient to restore full virulence in a mouse peritonitis model to a clinical Escherichia coli isolate, D551 (O78:H-), whose resident aerobactin-encoding ColV plasmid had been lost by curing. Antiserum was raised in rabbits against live E. coli K12 cells expressing the outer-membrane aerobactin receptor protein and absorbed with an isogenic strain lacking the receptor. This antiserum inhibited binding of aerobactin, cloacin DF13 and bacteriophage B74K to the native protein in whole E. coli K12 bacteria expressing the receptor, or in membranes prepared from such organisms. However, it did not react with the native receptor protein in several wild strains unless lipopolysaccharide was first removed by treatment with trichloroacetic acid, nor did it protect mice in experimental infections with strain D551. Antisera raised in rabbits against partially or fully denatured forms of the aerobactin receptor reacted only in assays involving denatured protein; they showed no inhibition of the biological activities of the native receptor.

Animals↗
PubMed1989

Influence of Lsh, H-2, and an H-11-linked gene on visceralization and metastasis associated with Leishmania mexicana infection in mice.

Visceral infection and metastatic lesion development following intravenous or subcutaneous inoculation of Leishmania mexicana amastigotes were examined in different B10 congenic mouse strains carrying alternative alleles at Lsh, H-2, or H-11. The results show that, despite a failure to observe any differences in rates of expansion of primary lesions in mice inoculated subcutaneously, each of these genes could be shown to exert some influence during visceralization and metastatic spread of L. mexicana infection. Of particular interest were (i) the continuous advantage observed throughout 160 to 200 days of infection in Lshr versus Lshs mice, (ii) the association between structural gene polymorphism at H-2 and profound visceral and metastatic spread of the parasite producing disease phenotypes akin to diffuse cutaneous leishmaniasis and post-kala-azar dermal leishmaniasis in humans, and (iii) similar effects observed in mice differing at H-11, the functional basis for which involves modified expression of major histocompatibility complex class II molecules. The results are discussed in relation to the human disease and the possibility that homologs for each of these genes regulate leishmanial infections in humans.

Animals↗
PubMed1989

Expression in Escherichia coli K-12 of the 76,000-dalton iron-regulated outer membrane protein of Shigella flexneri confers sensitivity to cloacin DF13 in the absence of Shigella O antigen.

One of the chromosomal segments associated with virulence in Shigella flexneri encodes the production of aerobactin and the synthesis of an iron-regulated 76-kilodalton outer membrane protein believed to be the ferric-aerobactin receptor. However, S. flexneri expressing this putative aerobactin receptor, which is slightly larger than that encoded by pColV, is insensitive to the killing action of cloacin DF13, a bacteriocin which binds to other aerobactin receptor proteins and kills the cells. In this paper we show that the conjugal transfer of DNA encoding the iron-regulated 76-kilodalton protein from S. flexneri to Escherichia coli K-12 conferred cloacin DF13 sensitivity on the recipients. However, E. coli K-12 which had also inherited genes specifying Shigella O-antigen biosynthesis remained cloacin insensitive. The data suggest that it is unwise to use cloacin DF13 sensitivity alone to screen transconjugants or clinical isolates for the expression of aerobactin receptor proteins.

Antigens, Bacterial↗
PubMed1989

The effects of age on isotypic antibody responses to Aspergillus fumigatus: implications regarding in vitro measurements.

The demonstration of elevated serum immunoglobulin E (IgE), immunoglobulin G (IgG), and immunoglobulin A (IgA) antibodies to Aspergillus fumigatus (Af) is a valuable aid in the serodiagnosis of allergic bronchopulmonary aspergillosis (ABPA). It is important to recognize cases of ABPA, because repeated untreated episodes of pulmonary infiltrates can result in bronchiectasis and even fatal fibrotic lung disease. Serum samples from patients with ABPA have increased isotypic antibodies to Af when compared with patients with asthma and immediate cutaneous reactivity but in whom ABPA has been excluded. There is little information regarding age-related changes of isotypic antibodies to a specific allergen or in comparison of such changes with age-related changes in total class-specific antibody. We determined IgE-Af, IgG-Af, and IgA-Af and total IgE, IgG, and IgA concentrations in serum samples from children with asthma (ages less than 1 through 5 years, 6 through 10 years, and 11 through 15 years) and compared the results with those in children with APBA and adults with asthma. The use of an indirect amplified ELISA with Af adsorbed to microtiter wells demonstrated that serum samples from children with ABPA have elevated IgE-Af, IgG-Af, and IgA-Af concentrations compared with those in serum samples from children with asthma. The assays were sensitive and highly specific in discriminating ABPA from asthma in children. Isotypic antibodies to Af in children do not demonstrate age-related increases as occur for total serum IgE, IgG, and IgA concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Brachylaima apoplania n. sp. (Digenea: Brachylaimidae) from the Polynesian rat, Rattus exulans (Rodentia: Muridae), in New Zealand: origins and zoogeography.

Brachylaima apoplania n. sp. is described from the small intestine of the Polynesian rat (Rattus exulans) on Tiritiri Matangi Island, New Zealand. The new species is most similar to Brachylaima ratti Baugh, 1962, from Rattus rattus. The two species differ only in morphometric characters, B. apoplania possessing significantly smaller suckers, pharynx, testes, ovary, and cirrus sac. The close resemblance between B. apoplania and B. ratti, the close relationship between their hosts, and archaeological evidence on the origin and early dispersal of R. exulans are used to hypothesize a common Southeast Asian origin for the 2 Brachylaima species. Brachylaima apoplania is believed to have dispersed subsequently throughout the South Pacific islands, along with its rodent host, in the canoes of the ancestors of the modern Polynesians and Maoris.

Animals↗
PubMed1988

Physiological and 15N-NMR analysis of molecular nitrogen fixation by Methanococcus thermolithotrophicus, Methanobacterium bryantii and Methanospirillum hungatei.

Two mesophilic methanogenic bacteria, Methanobacterium bryantii strain MOH and Methanospirillum hungatei strain GP1 were demonstrated, using several different experimental approaches, to fix dinitrogen. Evidence includes (1) growth with N2 as the sole nitrogen source; (2) incorporation of 15N2 into cellular material (both soluble amino acid pools and insoluble cell protein and other macromolecules) detected by 15N-NMR spectroscopy; (3) acetylene reduction to ethylene by the cells, and inhibition of this reaction by bromoethanesulfonic acid (BES), a methanogen inhibitor. High-resolution 15N-NMR analysis of ethanol extracts of these organisms and cross-polarization magic-angle sample spinning analysis of the solid debris from these extracts are compared to labeled material from Methanococcus thermolithotrophicus, a methanogen previously determined to fix dinitrogen.

Clostridium↗
PubMed1988

The 5' flanking region of the human pS2 gene mediates its transcriptional activation by estrogen in MCF-7 cells.

The pS2 gene is transcriptionally induced by oestrogen in the human breast cancer cell line MCF-7. We demonstrate here that the 5' flanking sequences (-3000 to +10 bp) of the pS2 gene possess the properties of an oestrogen-inducible promoter. Interestingly, this oestrogen induction could not be demonstrated in transient transfection assays in MCF-7 cells, but only in stably transformed MCF-7 cells, which suggests that some factors responsible for oestrogen induction may be present in limiting amounts in these cells and absent in HeLa cells.

Base Sequence↗