Search PubMed⌕ Search

Biomedical subjects

M Roberts

Publications and source records attributed to M Roberts.

At least 325 records · Page 18Linked to original sources
PubMed1980

Long-term corticosteroid effect on lymphocyte and polymorphonuclear cell function in asthmatics.

The effect of long-term alternate-day steroid administration on lymphocyte and polymorphonuclear cell (PMN) functions was studied in 10 steroid-dependent adult asthmatic patients. The duration of alternate-day prednisone usage ranged from 3 to 12 yr with an average of 6.7 +/- 3.6 yr. Maintenance steroid dosage at the time of study ranged from 20 to 50 mg on alternate days, averaging 31 +/- 8 mg. Prednisone caused marked lymphopenia, suppression of phytohemagglutin (PHA) lymphocyte transformation and PMN adherence 4 hr after ingestion. By 24 hr these measurements returned to normal or higher. These effects appeared at all doses between 20 and 50 mg of prednisone. In contrast, there was no statistically significant suppression of the total leukocyte count, total and active erythrocyte (E) rosette-forming lymphocytes, serum immunoglobulin concentrations, polymorphonuclear cell (PMN) phagocytosis, or delayed skin reactivity. We conclude that the acute effects of prednisone on lymphocyte and PMN function are transient and return to normal levels by 24 hr. The continued administration of beclomethasone dipropionate by inhalation did not interfere with the recovery of the transient leukocyte abnormalities induced by oral prednisone.

Asthma↗
PubMed1980

Expression of the lactose transposon Tn951 in Escherichia coli, Proteus and Pseudomonas.

The control of beta-galactosidase specified by the lactose transposon Tn951 (inserted into RP1 to give pGC9114) has been studied in Escherichia coli K12, Proteus mirabilis, Pseudomonas aeruginosa and Pseudomonas putida; in the first two species comparison could be made with Flac. In E. coli K12, the Tn951 and chromosomally encoded enzymes showed marked qualitative differences in regulatio, the former giving a substantially lower maximum induced level and induction ratio. Several parameters were slightly affected by strain background. In P. mirabilis, beta-galactosidase control determined by both Flac (in accord with earlier work) and pGC9114 was markedly different from E. coli in that maximal induced levels were about an order of magnitude lower and the induction ratio was reduced to 3 to 5. In Ps. aeruginosa and Ps. putida, Tn951-specified lac expression was qualitatively similar to that in P. mirabilis. Possible reasons for anomalous expression in Proteus and Pseudomonas are discussed.

DNA Transposable Elements↗
PubMed1980

Extended evaluation of allergic bronchopulmonary aspergillosis.

The clinical status and laboratory findings of 19 patients with allergic bronchopulmonary aspergillosis (ABPA) evaluated over a period ranging from 3 months to 10 years are reviewed (average 2.6 years). Criteria establishing the diagnosis of ABPA as well as an estimate of duration of ABPA prior to diagnosis in selected cases is presented. 10 of the 19 patients currently require chronic corticosteroids for control of asthma as compared to 4 patients at the time of initial diagnosis. 16 exacerbations of ABPA have occurred in 8 patients. There is no correlation between the severity of asthma and either the number of exacerbations or persistent radiographic stigmata of ABPA. Pulmonary function tests range from normal to obstructive and restrictive changes.

Adolescent↗
PubMed1980

Detection of antibodies in human serum using trimellityl-erythrocytes: direct and indirect haemagglutination and haemolysis.

Utilizing trimellityl-erythrocytes (TM-E), antibodies were detected in sera of seven workers with trimellitic anhydride (TMA) induced airway syndromes by direct haemagglutination, indirect haemagglutination with anti-human IgG, IgA or IgM or by haemolysis. Detectable levels of antibody were obtained with all three methods. The most sensitive technique was indirect haemagglutination using anti-IgG. When added as an inhibitor, TM-human serum albumin produced a 10- to 800-fold reduction in titres. TM-ovalbumin of similar epitope density was less inhibitory and sodium trimellitate the least inhibitory on a molar basis. All of the assays using haptenized human red cells were also capable of detecting anti-TM antibodies in Rhesus monkeys whose airways had been exposed to TMA. These assays are useful for detecting anti-TM antibodies and may also be adapted to demonstrate antibodies induced against other inhaled haptens in sera of environmentally exposed individuals or in animal models of such exposure.

Animals↗
PubMed1980

IgA antibody against Aspergillus fumigatus antigen in patients with allergic bronchopulmonary aspergillosis.

IgA antibodies against Aspergillus fumigatus (Af) antigen were measured by a radioimmunoassay in sera from patients with allergic bronchopulmonary aspergillosis (ABPA) and compared with IgA antibody levels in asthmatics who had positive prick tests to Af and normal controls. The assay for IgA antibody discriminated between both control groups and the ABPA group at two serum dilutions (10(-2) and 10(-3)) but did not discriminate all individual ABPA sera from the peak levels of antibody in the control groups. IgA antibody against Af may participate in the immunopathogenetics of pulmonary inflammation in some cases of ABPA and may be of some diagnostic value in some, but not all, cases.

Antigens, Fungal↗
PubMed1980

Antibodies in hemodialysis patients against hapten-protein and hapten-erythrocytes.

Serum samples obtained from hemodialysis patients with immediate-type hypersensitivity reactions and hemodialysis patients with no reactions were analyzed for antibody activity against hapten-protein complexes prepared from PA and MDI. These chemicals, used in preparation of plastics, have been shown to be associated with immunologically mediated disease in other studies. IgE and IgG antibodies against P-HSA and MDI-HSA were detected in several sera, but symptomatic patients could not be differentiated from asymptomatic patients by antibody levels. Antibodies capable of agglutinating or hemolyzing P-E were also detected in some sera from hemodialysis patients. These studies demonstrate that although no clinical disease has yet been correlated with these antibodies, sufficient exposure of hemodialysis patients to protein-reactive chemicals occurs to elicit an immunologic response against hapten-protein or hapten-cells. Such antibodies may have immunopathogenetic significance in subjects systemically exposed to fluids which have been in contact with plastics.

Albumins↗
PubMed1980

In vitro IgE formation by peripheral blood lymphocytes from normal individuals and patients with allergic bronchopulmonary aspergillosis.

Peripheral blood lymphocytes from five normal donors and five individuals with allergic bronchopulmonary aspergillosis (ABPA) were used for measurement of in vitro IgE formation in tissue culture preparations. IgE was measured by a sensitive radioimmunoassay using concentrated tissue culture medium (TCM) and expressed as ng IgE/ml of TCM. The results demonstrated that IgE was formed by unstimulated lymphocytes from one of five normal donors (range 1.5-2.4 ng/ml) and in two of five ABPA donors (range 2-4 ng/ml). However, when different dilutions of pokeweed mitogen were added to the tissue culture, three of five normal donors and three of five ABPA donors in remission showed enhanced IgE formation. At the time of an ABPA exacerbation in one individual, there was a definite increse in IgE synthesis up to 40 ng/ml which was suppressed by pokeweed mitogen to 17.3 ng/ml. Clear differences between normals and ABPA patients in remission are not apparent.

Aspergillosis, Allergic Bronchopulmonary↗
PubMed1979

Cytogenetic findings in Roberts-SC phocomelia syndrome(s).

Roberts syndrome and SC phocomelia syndrome are an autosomal recessive condition of prenatal and postnatal growth retardation, symmetrical limb reduction, and craniofacial abnormalities. A distinction has been made between the two syndromes on the basis of relative severity of these manifestations. Where chromosome studies have been carried out, most have been reported as normal. However, there have been two reports of consistent centromere abnormalities; one in a patient with SC phocomelia (pseudothalidomide syndrome), the other in a patient with Roberts syndrome. Four patients with similar phenotypic manifestations have recently been shown in our laboratory to have the same centromere puffing and splitting. These four patients had other clinical manifestations in common, including bilateral corneal opacities, microcephaly, absence of radii, limited extension at knees and elbows, apparent enlargement of the phallus, and survival beyond the neonatal period.

Abnormalities, Multiple↗
PubMed1979

Allergic bronchopulmonary aspergillosis in pediatric practice.

Twelve cases of allergic bronchopulmonary aspergillosis in the pediatric age group are reported. The average age of diagnosis was 14.5 years with a range from 6 to 18 years. All patients had a history of pulmonary infiltrations or atelectasis or both documented by chest radiographs. Eight patients had bronchograms or tomograms, and seven of them showed proximal bronchiectasis. Total serum IgE concentrations were elevated in all patients. Preciptitating antibodies against Aspergillus fumigatus were positive in all patients at the time of diagnosis, and became negative in some after therapy. The specific IgE or IgG antibody activity agaist Af was elevated in all 12 patients. After prednisone was started the total serum IgE sharply declined to a plateau and remained at this level until a flare of allergic aspergillosis occurred. A flare of allergic aspergillosis is characterized by an increasing total serum IgE concentration followed by pulmonary infiltration. Clinical and roentgenologic improvements were observed after steroid therapy. The importance and methods of early diagnosis in the pediatric population are discussed.

Adolescent↗
PubMed1979

The ecology of gonococcal plasmids.

Of 261 strains of Neisseria gonorrhoeae examined for plasmids, 6 were plasmid-free, 217 contained only a small multicopy 2.6 X 10(6) dalton plasmid and 38 carried a large 24.5 X 10(6) dalton plasmid. Restriction enzyme digests and DNA-DNA hybridization studies revealed that the large plasmids isolated between 1940 and 1978 share a common core of DNA sequences (70 to 100%) and represent a group of closely related molecules.

Base Sequence↗
PubMed1979

The evaluation of selected parameters of immune function in asthmatics after long-term corticosteroid therapy.

The availability of inhaled beclomethasone diproprionate permitted the discontinuation of continuous, long-term systemic corticosteroid therapy (SCT) in a group of asthmatics who had previously required SCT to control their asthma. Twelve patients had been on SCT for a period of 2-22 years with an average duration of 7 years. To determine whether this previous long-term SCT and the current use of inhaled beclomethasone diproprionate had an effect on leucocyte functions, a variety of studies reflecting T lymphocyte, B lymphocyte and granulocyte function was done. The results were compared with those of twelve asthmatic patients of similar age ranges who had never received steroids. Results showed that the two patient populations could not be differentiated on the basis of phytohaemagglutinin stimulation of lymphocytes, sheep erythrocyte rosette formation, IgG, IgA, IgM and IgE concentrations or granulocyte bactericidal activity. Delayed skin reactivity was present in both groups, with more positive reactions in the non-SCT group. Polymorphonuclear adherence values were slightly lower in the SCT female population using beclomethasone diproprionate. The latter two minor differences may be due to the previous SCT, the use of beclomethasone diproprionate or the limited population of patients studied. We conclude from these studies that the long-term use of SCT at the low doses required for control of asthma resulted in little permanent effect on the variety of lymphocyte and granulocyte functions tested.

Adrenal Cortex Hormones↗
PubMed1979

Applications of the Redy sorbent system to hemodialysis and peritoneal dialysis.

The application of sorbent technology to the treatment of uremia has been limited by the inability to adsorb urea adequately. Conversion of urea to ammonium carbonate and adsorption by zirconium phosphate provides a practical means of removing urea. This combination, together with hydrated zirconium oxide and carbon, removes uremic waste products from dialysate. Over 1500 patients are undergoing maintenance hemodialysis with this system. The dialysate composition can be modified for the treatment of patients with acute renal failure. This sorbent system is now being used for the regeneration of peritoneal dialysate. Twenty patients have undergone a total of 90 dialyses, each of 4 to 24 hours duration. One home patient has been solely on this system for two months. The application of sorbent technology to peritoneal dialysis may be the most promising approach to a wearable dialysis system.

Adsorption↗
PubMed1979

The management of allergic bronchopulmonary aspergillosis.

Twenty-five patients with allergic bronchopulmonary aspergillosis (ABPA) were observed for periods of 12 months to 10 years (average duration, 2.6 years) after initial therapy with prednisone, which was then tapered and discontinued unless maintained at minimal doses as required for control of asthma. Thirteen patients have had no recurrence, 4 patients did not comply with the initial regimen and could not be considered to be controlled, and 8 patients had 12 recurrent episodes of ABPA characterized by pulmonary infiltrates with no explanation other than ABPA. The exacerbations were closely correlated with sharp increases in total serum IgE, which subsequently decreased after resumption of prednisone therapy. The increase of IgE preceded the pulmonary infiltrates in 7 or 12 exacerbations. The exacerbations, characterized by increased serum IgE and pulmonary infiltrates, may be associated with minimal symptoms. Acute asthma without pulmonary infiltrates was not associated with increased IgE. Four exacerbations occurred during administration of beclomethasone diproprionate used for control of asthma, and therefore, this agent does not appear to prevent or reverse exacerbations of ABPA. Twelve exacerbations occurred in 8 persons, with 2 patients having 4 and 2 recurrences, respectively. This suggests that exacerbations are more likely to occur in certain patients. Serial measurements of total serum IgE appears to be a useful index of disease activity in ABPA. In the 4 patients who did not comply with the prednisone therapy regimen or regular physician visits, patterns of IgE changes, clinical evaluations, and chest roentgenograms were not of use in evaluation of the clinical state or progress of the patient. A treatment regimen is suggested for initial therapy and recurrences of ABPA on the basis of these observations.

Aspergillosis, Allergic Bronchopulmonary↗