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Biomedical subjects

B David

Publications and source records attributed to B David.

At least 181 records · Page 10Linked to original sources
PubMed1981

Grass pollen hyposensitization versus placebo therapy. I. Clinical effectiveness and methodological aspects of a pre-seasonal course of desensitization with a four-grass pollen extract.

The present work reports the results of a double-blind clinical trial, comparing the effects of hyposensitization treatment versus placebo in 33 patients with allergic rhinitis, sensitive to a crude extract of the pollen of four different grasses (Dactylis glomerata, Lolium perenne, Secale cereale, and Phleum pratense). The distribution of these patients in the two groups was done randomly and gave two comparable groups, as far as clinical and biological features are concerned. The treatment course included five low doses of the aqueous extract followed by 12 injections of Al(OH)3-adsorbed aliquots of the same extract. Evaluation of the clinical scores was based on diary cards on which symptoms and medications were recorded. A reevaluation of the significance of the symptom and medication scores is presented and the link between both scores is studied. Particular attention is given to the methodological and statistical problems raised during this study. The non-parametric tests reveal a significant difference (P less or equal to than 0.03) in the total clinical score between the treated and the placebo groups for the second half of the observation period, when the pathology was most intense.

Adolescent↗
PubMed1981

Antigens and allergens in Dermatophagoïdes farinae mite. I. Immunochemical and physicochemical study of two allergenic fractions from a partially-purified Dermatophagoïdes farinae mite extract.

The fractionation of a partially-purified extract of Dermatophagoïdes farinae mite culture has been undertaken by gel filtration. Two fractions were isolated. One, P25, is a protein-rich fraction with mol. wt about 25,000. The other, GP8, is a polysaccharide-rich fraction with mol. wt around 8,000. By crossed immunoelectrophoresis, we detected eleven antigens in the partially-purified dialysed D. farinae extract (Df 80d) as well as in P25 fraction. One of them, ag 11, seems the most important allergen since in crossed-radio immunoelectrophoresis experiments it displays the faster radiostaining, implying that it binds the greatest part of the mite-specific IgE present in a pool of sera from mite-sensitive patients. By crossed-line immunoelectrophoresis, we demonstrated the absence of ag 11 in GP8, in which only ag 5 and ag 6 were identifiable. By radioalloergosorbent tests (RAST), it was found that P25- and GP8- coated paper discs can fix specific IgE induced in the majority of D. farinae sensitive patients. Defining a 'major allergen' as an allergen to which the majority of sensitive patients develop specific IgE, both P25 and GP8 do appear to contain at least one major allergen. By RAST inhibition method, using Df 80d as a solid phase, the allergenic activity of P25 appeared as slightly higher than that of Df 80d, whereas GP8 displayed a very weak inhibitor capacity. Thus, the allergic specificity of GP8 differs from that of Df 80d or P25.

Allergens↗
PubMed1980

Studies on Dermatophagoides pteronyssinus allergens: measurement of the relative potencies of D. pteronyssinus purified extracts by in vitro and in vivo methods.

To standardize the Dermatophagoides pteronyssinus extracts used in clinical allergy practice, the relative potencies of several purified extracts were estimated by radioallergosorbent test (RAST) inhibition, histamine release, and intracutaneous titration testing, and the results were compared. The potencies of nine independently prepared D. pteronyssinus extracts were assayed with respect to an extract adopted as a reference. In vivo the cutaneous wheal surface after intradermal injections was measured on a population of D. pteronyssinus-sensitive subjects. In vitro RAST inhibition was performed with the reference extract as allergosorbent and with a pool of human IgE-rich sera from patients sensitized to D. pteronyssinus but untreated. For histamine release human basophils from patients allergic to D. pteronyssinus were used. In the three method dose-response curves were plotted for the reference extract and the other extracts. A comparison of the measurement of in vitro and in vivo potencies is reported. Simialr results were obtained with the three methods: all the extracts but one were as potent as the reference preparation. However, for routine purposes RAST inhibition appears to be the most convenient and reliable procedure.

Allergens↗
PubMed1980

[Echograpic diagnosis of a rare malformation: iniencephaly (author's transl)].

We describe a case of iniencephaly, which is a maldevelopment rare enough to warrant the publication of known cases. The ultrasound pictures that are taken and presented show a spina bifida and an omphalocoele were associated with the cerebral abnormality. It is further confirmation of the great value of routine ultrasound making early diagnosis of fetal malformations.

Adult↗
PubMed1979

[Acute leukaemia with lymphoblastic features occurring during myeloma (author's transl)].

Leukaemias which complicate myeloma under treatment are usually acute non-lymphocytic leukaemias. We report here a case of acute leukaemia with lymphoblastic features occurring 30 months after diagnosis of myeloma. The exceptional character of this association lead us to refine the cytological diagnosis by studying surface markers and ultrastructural cytochemistry. Because of the absence of T or B markers, and the absence of peroxidase activity in the nuclear envelope, the endoplasmic reticulum, and the Golgi apparatus of blastic cells, we conclude that this leukaemia is "null" lymphoblastic.

Acute Disease↗
PubMed1978

Early vulvar carcinoma.

Fifty-eight cases of early vulvar neoplasia were reviewed from the Tumor Registry at Magee-Womens Hospital, between 1947 and 1976. Twenty-three cases were carcinoma in situ; 16 were microinvasive, and 19 were occult carcinoma. All of the cases were treated surgically. The modality of surgical treatment varied from local excision to radical vulvectomy with inguinal lymph node dissection. Regardless of the surgical therapy, none of the patients died of the vulvar malignancy. It is recommended, as part of routine gynecologic surveillance, that more critical attention be given to examination for early epithelial neoplastic lesions of the vulva. This can be accomplished by simple inspection and the use of special diagnostic aids. Biopsy specimens should be reviewed histologically for depth of invasion and the treatment individualized to the patient with considerations for conservatism, especially in younger women.

Adult↗
PubMed1978

Cellular histamine release, specific and total serum IgE levels in hay fever patients and controls.

The amount of histamine released from blood leucocytes by allergen, the amount of allergen required to release 50% histamine and the total IgE and IgE specific for Dactylis glomerata are compared in nine hay fever patients and five control individuals. The variation with time of total IgE, of specific IgEe and of the percentage of histamine released at a fixed allergen concentration, corresponding to the cellular sensitivity, is shown for one control individual with positive in vitro and skin tests, but without clinical symptoms. For four patients with a low total IgE level the evolution of these parameters during a 1 year treatment period is presented.

Adult↗
PubMed1978

Magnetic enzyme immunoassay of anti-grass pollen specific-IgE in human sera.

This paper reports a magnetic solid-phase sandwich enzyme immunoassay for specific IgE antibodies in human sera. Crude extracts of grass pollen bound to magnetic polyacrylamide agarose beads were mixed with human serum to be tested. After washing in a magnetic rack, the beads were incubated with the glucose-oxidase-labelled sheep anti-IgE. The enzyme activity associated with the beads was measured by colorimetric assay. Results obtained from sixty-one human sera, as measured by the magnetic enzyme immunoassay, gave a linear correlation coefficient of 0.98 with the values as determined by radio-immunoassay. This procedure, which allows the grass pollen specific IgE in human sera, to be measured, is easy to perform, reproducible and may avoid the use of radioactive compounds.

Antibody Specificity↗
PubMed1976

[Intracellular histamine content in human basophils and individual variation in allergic persons during densensitization].

A positive correlation has been found to exist between the percentage of basophiles and the histamine content in a suspension of washed human leukocytes obtained from allergic and healthy donors. The mean value of histamine per basophile was 1,9 +/- 0,3 pg. The leukocyte histamine content was measured as a function of time in a non-allergic person and during the desensitization period of allergic patients.

Basophils↗
PubMedDate not supplied

Congestive heart failure due to diastolic or systolic dysfunction. Frequency and patient characteristics in an ambulatory setting.

OBJECTIVE: To determine the age- and sex-specific frequencies and characteristics of patients with diastolic and systolic dysfunction heart failure. DESIGN: Retrospective medical record survey encompassing 1 year. SETTING: Community-based family practice office. PATIENTS: One hundred thirty-six patients who met the modified Framingham criteria for the diagnosis of congestive heart failure (CHF) and had a known left ventricular ejection fraction. Diastolic dysfunction was defined as an ejection fraction of 45% or greater and systolic dysfunction heart failure as an ejection fraction of less than 45%. MAIN OUTCOME MEASURES: Age- and sex-specific frequency; patient comorbid conditions; medications taken; and number of emergency department visits, hospitalizations, and deaths. RESULTS: The frequency of CHF increased with age for men and women (1.3% for patients 45-54 years old to 8.8% for patients > 75 years old). The distribution according to left ventricular ejection fraction and age varied according to sex. Women had later onset of CHF that was predominantly diastolic dysfunction heart failure. Men had proportionately more systolic dysfunction heart failure at all ages. Forty percent of all patients with CHF had diastolic heart failure, and these patients had fewer functional limitations (76% with New York Heart Association classes I and II), fewer hospitalizations for CHF, and a trend toward fewer deaths during the study year compared with patients with systolic dysfunction. CONCLUSIONS: Congestive heart failure is a heterogeneous condition in this family practice setting, and diastolic dysfunction heart failure occurs frequently. Further study of the natural history and treatment of diastolic dysfunction heart failure should be performed in the primary care setting.

Aged↗
PubMedDate not supplied

Ultrastructural changes in mouse peritoneal mast cells in response to L-leucine methyl ester or anti-IgE.

We studied the ultrastructural features of mouse peritoneal mast cells in response to a non-immunologic lysosomotropic agent, L-leucine methyl ester (Leu-OMe), as compared to well-known immunologic stimulation mediated by anti-IgE antibodies. Total peritoneal exudate cells were collected from CBA/J mice, with mast cells representing 3 to 8% of total cells. The secretory granules in unstimulated mast cells were heterogeneous in size and shape, but intragranular material displayed a homogeneous electron-dense appearance. Stimulation with either Leu-OMe, for Leu-OMe doses lower than 1.5 mM, or anti-IgE was associated with fusion of the granule membranes with one another and with the plasma membrane, as evidenced by morphologic changes noted by electron microscopy. Ultrastructurally, electron density characterizing the granular matrix decreased to varying degrees in the granules, as did its homogeneity, even within a given mast cell. At higher Leu-OMe doses (> 1.5 mM), the effect of this lysosomotropic compound on mast cells was associated with an apparent loss of membrane and cellular integrity, suggesting high Leu-OMe dose-mediated cytotoxicity. These results show that activation induced in mouse peritoneal mast cells by Leu-OMe and anti-IgE may have distinct characteristics, as assessed by morphologically different patterns. Furthermore, high Leu-OMe doses (> 1.5 mM) induced cytotoxicity targeted toward mast cells.

Animals↗
PubMedDate not supplied

Calcium-phosphate-adjuvanted allergens: total and specific IgE levels before and after immunotherapy with house dust and Dermatophagoides pteronyssinus extracts.

Results of total and specific IgE levels before and after immunotherapy carried out with calcium-phosphate-adjuvanted house dust and mite allergens for 36 patients are reported here. Total and specific IgE levels were evaluated by radioimmunological methods based on the IgE/anti-IgE interaction. Total IgE levels were not significantly different before and after immunotherapy; most of the specific IgE levels remained on the same order. IgE levels after immunotherapy varied only slightly in most patients and were not correlated with therapeutic results. Advantages of calcium phosphate compared to aluminium compounds are reported.

Adjuvants, Immunologic↗
PubMedDate not supplied

Production of a monoclonal antibody against a major allergen of Dactylis glomerata pollen (Dg1).

A mouse monoclonal antibody was produced against the most frequent allergen Ag Dg1ief, purified from the Dactylis glomerata grass pollen by isoelectric focusing. Using the immunoprint technique, this monoclonal antibody detected Ag Dg1ief in D. glomerata pollen and some cross-reacting molecules in four other grass pollens. This hybridoma was grown in ascitic fluid. An immunosorbent was made from it and, by affinity chromatography, was used to purify monoclonal Ag Dg1m from the pollen extract. Ag Dg1m (6,000 to 8,000 daltons) appeared to be 4 to 5 times smaller than Ag Dg1ief. It appeared as a weak allergen in passive cutaneous anaphylaxis in rats, but was more potent in triggering histamine release on human basophils from grass-pollen sensitive patients. These results suggest that Ag Dg1m could be a part of the Ag Dg1ief used to induce production of this monoclonal antibody.

Animals↗
PubMedDate not supplied

Biological effect of transferrin on mast cell mediator release during the passive cutaneous anaphylaxis reaction: a possible inhibition mechanism involving iron.

A purification procedure for passive cutaneous anaphylaxis inhibitory factor from BALB/c mouse serum has been previously described. In the present work, this inhibitory activity was found to be related to transferrin. No activity was obtained using iron-unsaturated transferrin, whereas iron-saturated transferrin appeared to be potent. The in vivo inhibition of IgE-dependent mediator release from rat mast cells was also obtained using free iron. This effect was observed when iron was injected prior to or simultaneously with mouse IgE in rat skin. Iron and iron-saturated transferrin could play a role in the mechanism of desensitization by modulating the responsiveness of mast cells.

Animals↗
PubMedDate not supplied

Comparison of the allergenic potency of spores and mycelium of Cladosporium.

The allergenic potency of spore and mycelium extracts of Cladosporium was estimated by RAST, RAST inhibition and PCA tests. Spores contained a concentration of allergens higher than mycelia. Results of PCA tests suggested that spores contained specific allergens. However, in a comparative study of extracts from different species of Cladosporium animal and human models gave different estimates of the allergenic potency of the different species. In spite of these variations it was shown that extracts from spores of Cladosporium contained the highest amount of Cladosporium allergens.

Animals↗
PubMedDate not supplied

Nonspecific B and T cell-stimulatory activity mediated by mast cells is associated with exosomes.

Bone marrow-derived mouse mast cells (BMMC) and mast cell lines P815 and MC9 have recently been shown to induce antigen-independent B and T lymphocyte activation. It has been demonstrated that a physical contact between mast cells and B and T lymphocytes is not necessary since mast cell supernatants contain full activity. Electron microscopy studies revealed the presence in mast cell supernatants of small vesicles called exosomes with a heterogeneous size from 60 to 100 nm of diameter. When cocultured with spleen cells, purified exosomes induce B and T cell blast formation, proliferation as well as IL-2 and IFN-gamma production. In contrast to P815 and MC9 mast cell lines, a pretreatment with IL-4 is required for BMMC to produce active exosomes. Structurally, these exosomes were found to harbor immunologically relevant molecules such as MHC class II, CD86, LFA-1 and ICAM-1. Here we provide for the first time the evidence that mast cells use exosomes as sophisticated messengers to communicate with cells of the immune system.

Animals↗