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Biomedical subjects

M Roberts

Publications and source records attributed to M Roberts.

At least 19 recordsLinked to original sources
PubMed1992

Muscarinic receptor subtypes, beta-adrenoceptors and cAMP in the tracheal smooth muscle of conventional and double-muscled calves.

The total muscarinic (M1 + M2 + M3) and beta-adrenergic receptors in the tracheal smooth muscle of conventional and double-muscled calves were identified and characterized with the non-specific antagonists [3H]quinuclidinyl benzilate ([3H]QNB) and [3H]dihydroalprenolol ([3H]DHA) respectively. Although the quantity of beta-adrenoceptors in double-muscled calves was 25% lower (p < 0.05) than in conventional calves (Bmax = 327 +/- 89 fmol/mg protein), adenylate cyclase assays indicated that the basal adenylate cyclase activity and the (-)-isopropylnoradrenaline (ISO)- and sodium fluoride (NaF)-stimulated values were not significantly different between these calves. However, the density of muscarinic receptors in double-muscled calves was 40% higher (p < 0.01) than in conventional calves (Bmax = 2955 +/- 625 fmol/mg protein). Subtypes of muscarinic receptors were studied with [3H]telenzepine (M1-receptors), [3H]AF-DX 384 (M2-receptors) and [3H]4DAMP (M1 and M3-receptors). It was found that in both double-muscled and conventional calves about 40% of the receptors were of the M3-subtype, the remaining 60% being M2-receptors. From these results, it is suggested that inflammation of the respiratory tract in double-muscled calves may be complicated by an imbalance between the cholinergic bronchoconstrictor and the beta-adrenergic bronchodilator components of the autonomic nervous system.

Animals↗
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↗
PubMed1979

IgA and IgG antibody activities of serum and bronchoalveolar fluid from symptomatic and asymptomatic pigeon breeders.

Serum IgA and IgG antibody activities against pigeon serum were measured in 16 symptomatic pigeon breeders, 20 asymptomatic pigeon breeders, and 3 normal subjects by radioimmunoassay. The IgA and IgG antibody activities against pigeon antigen of the group of patients with disease was significantly greater than those of patients in the asymptomatic and the control group. The overlap of results for the symptomatic and asymptomatic breeders limits the diagnostic value of these individual IgA or IgG antibody determinations. Bronchoalveolar fluid and serum samples from a smaller group of pigeon breeders who underwent lung lavage were available for studies of antibody activity against pigeon serum. Ten asymptomatic and 6 symptomatic breeders were available for study. Both IgG and IgA antibody activities were detected by radioimmunoassay in serum samples and bronchoalveolar fluid. The IgA antibody activity determined by the radioimmunoassay was higher in the respiratory secretions.

Alveolitis, Extrinsic Allergic↗
PubMed1979

Is a healthier person less susceptible to noise-induced hearing loss?

Several studies in the literature suggest that poor health is related to hearing loss. One hundred subjects claiming occupational hearing loss were chosen randomly for this study. Information was obtained on employment, noise exposure, medical history, family history, and use of cigarettes, alcohol, and medication. Physical examination audiometric tests, and biological tests were carried out. Computer analysis of the data with chi-square test did not show conclusively that noise-induced hearing loss is related to poor health, indicated by abnormal biological or physical findings, or both. There were, however, some indications that the presence of cardiovascular risk factors may influence hearing loss.

Analysis of Variance↗