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Biomedical subjects

M Roberts

Publications and source records attributed to M Roberts.

At least 181 records · Page 10Linked to original sources
PubMed1993

Immunity after treatment of human schistosomiasis: association between cellular responses and resistance to reinfection.

Previous studies have demonstrated the development of an age-dependent resistance to reinfection after chemotherapeutic cure of the helminthic parasite Schistosoma mansoni. Here we report on a longitudinal investigation of cell-mediated responses in infected individuals before and after treatment which was designed to outline those parameters important in mediating a protective response. A well-defined study group of 89 individuals with an age range of 9 to 35 years was selected from an area of high S. mansoni transmission in the Machakos district of Kenya. Peripheral blood mononuclear cell proliferation and cytokine production (interleukin-2 [IL-2], gamma interferon IL-5, IL-4, and tumor necrosis factor) in response to different crude life cycle-stage antigens of S. mansoni were assessed longitudinally in vitro before, 3 months after, and 1 year after treatment. Detailed statistical analyses of the results from this study have indicated a clear negative association between the proliferative responses to adult- and schistosomulum-stage antigens and subsequent reinfection intensity in older individuals (14 to 35 years) which was not present in the younger individuals (9 to 13 years). This association was significant even after the effects of age, sex, and exposure had been accounted for in multiple regression analyses. Cytokines were detected predominantly in response to adult worm and egg antigen extracts. An inverse association between the two cytokines gamma interferon and IL-5 was detected in response to all antigens at the three time points investigated, indicating cross-regulation in the production of these two mediators. Differences in antigen-specific cytokine levels between the two age groups were detected, with significantly higher IL-5 levels detected in the older (more resistant) age group. An inverse correlation between this cytokine and reinfection was detected but could not be dissociated from the effects of age and exposure in multiple regression analysis.

Adolescent↗
PubMed1993

Allergic bronchopulmonary mycosis caused by Pseudallescheria boydii.

Two cases of allergic bronchopulmonary pseudallescheriosis (ABPP) are described. These are the first cases of this allergic bronchopulmonary mycosis (ABPM) reported in which the clinical and serologic criteria are described. The first case was in a patient with mild asthma, and it resolved spontaneously after expectoration of a mucous plug. The second was in a patient with recurrent allergic bronchopulmonary aspergillosis with an exacerbation of ABPM caused by Pseudallescheria boydii. The total serum IgE, IgG, and IgE antibodies against P. boydii and the clinical picture well define ABPP. This diagnosis may be important to recognize in order to prevent a progression of the patient's lung disease.

Adult↗
PubMed1993

N-ras mutation in acute myeloid leukemia: incidence, prognostic significance and value as a marker of minimal residual disease.

The polymerase chain reaction (PCR) and allele specific oligonucleotide (ASO) hybridization have been used to investigate the incidence of N-ras mutation in acute myeloid leukemia (AML). The prognostic significance of these mutations and their value as markers of minimal residual disease have also been assessed. Mutated N-ras alleles were detected in 9 of 69 AML patients (13%). No significant difference in survival or remission duration was found between those patients with an N-ras mutation and those without. Four patients with N-ras mutations at presentation were followed through disease progression. The results showed no consistent pattern of association between the presence of an N-ras mutation and disease state.

Adolescent↗
PubMed1993

Allergic bronchopulmonary aspergillosis in patients with and without evidence of bronchiectasis.

Allergic bronchopulmonary aspergillosis (ABPA) may complicate 1% to 2% of all cases of chronic asthma. Twenty-eight patients fulfilling the diagnostic criteria for ABPA but without evidence of proximal bronchiectasis [ABPA-S (seropositive)] were identified over a 12-year period and classified by stage. The majority of patients were in remission but all had chronic asthma. Serum anti-Aspergillus fumigatus (Af) IgG was lower in ABPA-S (n = 28) versus ABPA-CB (central bronchiectasis) (n = 58) at the time of initial presentation (IgG-Af index 3.62 versus 7.80, t = 3.46, P < or = .001). Serum IgG1-Af was significantly lower in ABPA-S as compared with ABPA-CB (t = 2.37, P = .011), as was serum IgG2-Af (t = 1.91, P = .031) and serum IgG4-Af (t = 1.78, P = .041). There were trends toward lower concentrations of total serum IgE, serum anti-Af-IgE, and anti-Af-IgA in ABPA-S. Eleven patients with ABPA-S were evaluated closely for a total of 63 patient-years and only four exacerbations with pulmonary infiltrates were identified. No patient in either group was observed to progress to end-stage or irreversible lung disease when early recognition and treatment were instituted. We conclude that ABPA-S represents the earliest stage or apparently a less aggressive form of ABPA.

Adolescent↗
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↗
PubMed1992

Allotype-dependent stimulation of peripheral blood and synovial lymphocytes by IgG3 in rheumatoid arthritis.

The immunopathologic process of rheumatoid arthritis (RA) is primarily expressed in the synovium where rheumatoid factor (RF) synthesis is concentrated. We hypothesized that RF synthesized by rheumatoid synovial cells (RSC) may be driven via a T cell-mediated immune response developed against IgG3 epitopes. To identify and characterize specific RSC RF epitopes and T cell antigens, two 28 amino acid peptides homologous with the C-terminus of IgG1 (P1) and IgG3 [G3m(5)] (P3) were synthesized and used in RF-binding studies and lymphocyte proliferation assays. Our results indicate that (i) the C-terminus of the CH3 domain contains epitopes for IgG3-reactive RSC RF; (ii) IgG3-reactive RSC RF binds primarily to IgG3 [G3m(5)]; (iii) P3 stimulated proliferation of T lymphocytes from both RA peripheral blood and RSC; and (iv) RF production was enhanced by P3 in selected RA cell cultures. These observations suggest that the C-terminus of IgG3 allotype G3m(5) may be important in T cell activation and RF production in RA.

Amino Acid Sequence↗
PubMed1992

Recombinant P.69/pertactin: immunogenicity and protection of mice against Bordetella pertussis infection.

The immunogenicity of recombinant (r-) pertactin was examined. Parenteral immunization of mice with natural or r-pertactin produced a similar increase in serum anti-pertactin antibodies and a decrease in Bordetella pertussis lung counts following aerosol challenge. Study of the kinetics of B. pertussis growth in the respiratory tract of immunized and control mice revealed that immunization with r-pertactin halted the multiplication of B. pertussis in the lungs and facilitated the early onset of bacterial clearance. In the trachea, bacterial numbers declined sharply in immunized animals during the first 3 days after challenge but thereafter B. pertussis numbers remained fairly constant throughout the rest of the experiment. Very low doses (0.1 micrograms) of r-pertactin were immunogenic and protective but only if the antigen was absorbed to alhydrogel. In vitro proliferation assays with lymphocytes from mice primed with either natural or r-pertactin indicated that the major T-cell epitopes of pertactin are conserved in the recombinant protein.

Adjuvants, Immunologic↗
PubMed1992

Nonimmune fetal hydrops caused by bilateral type III congenital cystic adenomatoid malformation of the lung at 17 weeks' gestation.

Type III congenital cystic malformation of the lung with nonimmune hydrops and oligohydramnios was diagnosed at 17 weeks by ultrasonography. Massive fetal cardiac compression with probable associated left- and right-sided failure causing both the oligohydramnios and the ascites, respectively, was thought to be the underlying pathophysiologic mechanism of this unusual clinical presentation. Pathologic examination after termination of the pregnancy confirmed the prenatal diagnosis.

Adult↗
PubMed1992

Anaphylactoid reaction to iopamiro (after pretreatment).

A patient is described with a past history of an anaphylactoid reaction to contrast media who reacted to nonionic contrast media after pretreatment with antihistamines and steroids. The available options to reduce the incidence of reactions include use of non-ionic contrast which has a reported lower frequency than ionic contrast or some form of pretreatment. Various forms of pretreatment have been described and in the majority steroids and antihistamines are used. We describe a patient who reacted to nonionic contrast after a pretreatment regime.

Anaphylaxis↗
PubMed1992

Characterization of a Salmonella typhimurium aro vaccine strain expressing the P.69 antigen of Bordetella pertussis.

The P.69 Bordetella pertussis protective antigen was expressed by use of the trc promoter from the chromosome of a Salmonella typhimurium aro vaccine strain, BRD509, by integrating the prn gene, encoding the 93-kDa precursor of this protein, into the aroC locus. P.69 was detected on the cell surface of the S. typhimurium strain (BRD640) by agglutination and immunoelectron microscopy. BALB/c mice immunized orally or intravenously with BRD640 showed a significant level of protection against an aerosol challenge with virulent B. pertussis, compared with control animals. No anti-P.69 antibodies in the serum or anti-P.69 antibody-secreting cells in the lungs were detected in BRD640-vaccinated animals, although cells isolated from spleens showed a P.69-dependent cell proliferative response. In contrast, low levels of anti-P.69 antibodies in the serum and anti-P.69 antibody-secreting cells in the lungs were detected in immunized mice following a B. pertussis challenge.

Adhesins, Bacterial↗
PubMed1992

Future perfect.

Shrunken and frail as winter birds, a tiny man and woman negotiate the short walkway and stairs to the geriatric day hospital at UTMB, Galveston. The man has one hand on his cane, the other his wife's arm--whether for gallantry or his own support is not clear. Nor is it immediately clear, once inside, that they've entered a hospital rather than a senior citizens center. Created to fill the multiple needs of a specific population, the day hospital is a modest experiment that may harbinger the future for health care delivery.

Aged↗
PubMed1992

Country life, human values.

With small-town roots and statewide vision, Larry Krupala takes on the THA chairmanship. Meet the man who'll be leading THA through the 1992-93 year.

Chief Executive Officers, Hospital↗
PubMed1992

Errors in fluid balance with pump control of continuous hemodialysis.

The use of pumps both proximal and distal to the dialyzer during continuous hemodialysis provides control of dialysate and ultrafiltration flow rates, thereby reducing nursing time. However, we had noted unexpected severe extracellular fluid depletion suggesting that errors in pump delivery may be responsible. We measured in vitro the operation of various pumps under conditions similar to continuous hemodialysis. Fluid delivery of peristaltic and roller pumps varied with how the tubing set was inserted in the pump. Piston and peristaltic pumps with dedicated pump segments were more accurate. Pumps should be calibrated and tested under conditions simulating continuous hemodialysis prior to in vivo use.

In Vitro Techniques↗
PubMed1991

No more knives.

Explore the source record for details and available documents.

Abdomen↗