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Biomedical subjects

B Diamant

Publications and source records attributed to B Diamant.

At least 55 records · Page 3Linked to original sources
PubMed1977

Sodium fluoride--a stimulus for a calcium-triggered secretory process.

Calcium triggers the secretion of histamine from mast cells after previous exposure of the cells to sodium fluoride. The secretory process can be divided into a fluoride-activating step and a calcium-induced secretory step dependent on cellular metabolic energy. The secretory response induced by compound 48/80 in the absence of extracellular calcium was found to decrease after fluoride pretreatment of the cells. The response was, however, unaffected, provided calcium was introduced to the cells simultaneously with compound 48/80.

Animals↗
PubMed1976

Studies on histamine-retaining granules obtained from isolated rat mast cells.

Histamine-retaining granules were isolated from rat mast cells after sonication in either sucrose of Ficoll-Hypaque media. The preparations obtained were compared in regard to recovery and spontaneous loss of histamine. The effect of agents known to release histamine from intact rat mast cells (antigen, compound 48/80, decylamine, the ionophores A23187 and X537A as well as ATP) was studied on the granules. Antigen and compound 48/80 did not release histamine. Decylamine and X537A induced a pronounced release independent of the presence of divalent cations. ATP caused a small, but significant release, which showed an absolute requirement for magnesium. A23187 released histamine only in the presence of either calcium or magnesium, and this release was unaffected by certain agents known to inhibit histamine release from intact rat mast cells. The results seem to exclude the possibility that agents known to induce release of histamine from intact rat mast cells by a calcium-and energy-dependent process would exert this action through a direct effect on intracellularly localized granules.

Adenosine Triphosphate↗
PubMed1976

Flour allergy in bakers. I. Identification of allergenic fractions in flour and comparison of diagnostic methods.

Extract of wheat flour obtained by extraction, centrifugation and dialysis was immunochemically characterized by quantitative immunoelectrophoresis using rabbit antibodies. The analysis revealed wheat flour to be composed of 40 antigens, some of which were immunologically partially identical with antigens of rye flour and of common grass pollen. Furthermore, antigens of the gliadin fraction of wheat flour were identified. 25 bakers with allergic complaints working in and around Copenhagen were clinically tested with wheat flour and related extracts. Among 13 bakers with respiratory complaints (asthma and/or rhinitis), 11 showed positive reactions to wheat flour extract when tested in histamine release from basophil leukocytes radioallergosorbent test and skin test, whereas further 2 were positive in the basophil test only. The ability of the IgE of individual sera to adsorb to the individual antigens of wheat flour was examined by means of crossed radioimmunoelectrophoresis. On the basis of these results, individual allergenic components of wheat flour were identified, three of these with comparatively high affinity and frequency.

Antigens↗
PubMed1975

Effects of adenosine-5'-triphosphate (ATP) on rat mast cells: influence on anaphylactic and compound 48/80-induced histamine release.

Anaphylactic histamine release from mast cells isolated from actively sensitized rats was inhibited by pre-incubation with micromolar concentrations of ATP. The inhibition was reversible under various experimental conditions and was counteracted by the presence of calcium in the incubation medium. Histamine release induced by compound 48/80 was similarly affected. Mast cells exposed to antigen under conditions when histamine release was inhibited by ATP became desensitized. The results indicate that ATP inhibits the release mechanism at a step which occurs after the binding of antigen to IgE.

Adenosine Triphosphate↗
PubMed1975

The influence of phosphatidyl serine on the release of histamine from isolated rat mast cells induced by different agents.

The influence of phosphatidyl serine (PS) on histamine release from isolated rat mast cells induced by antigen, compound 48/80, adenosine-5'-triphosphate (ATP), the ionophore A23187, and decylamine was studied. PS enhanced antigen-induced release but inhibited the release caused by compound 48/80, A23187, and decylamine. PS did not influence the release induced by ATP. The different effects of PS on the action of the various histamine releasing agents do not conform to a unifying model for the action of PS on the release process. Possible interactions between PS and the agents in the incubation medium as well as at specific reactive sites on the plasma membrane might explain some of the effects of PS. Consequently, the results cannot be used as evidence for the existence of basic differences in the release process induced by various calcium- and energy-dependent releasing agents.

Adenosine Triphosphate↗
PubMed1975

Assessment of left ventricular function in secundum atrial septal defect: evaluation by determination of volume, pressure, and external systolic time indices.

Left ventricular function and volume data from 17 control subjects and 27 young patients with secundum atrial septal defect (ASD) without overt left or right ventricular failure were compared. ASD patients were subdivided in low shunt (Qp/Qs less than 2.0) and high shunt (Qp/Qs larger than or equal to 2.0) groups. Mean left ventricular (LV) stroke volume was significantly less in ASD patients (46 +/- 16 ml/m2 in the low shunt and 44 +/- 9 ml/m2 in high shunt group) compared with control patients (51 +/- 13 ml/m2, P less than 0.01 and P less than 0.02, respectively). There was no significant difference in mean left ventricular end-diastolic volume (LVEDV) between any group of patients (control subjects 67 +/- 17 ml/m2; low shunt ASD 66 +/- 17 Ml/m2, and high shunt ASD 62 +/- 12 ml/m2). High shunt ASD had a significantly lower cardiac index compared with control patients (5.0 liters/min/m2 vs. 5.9 liters/min/m2, P less than 0.02). Both low shunt and high shunt ASD showed significantly lower stroke work indices than control subjects (42 +/- 13 GmM/m2 and 37 +/- 8 GmM/m2 compared with 51 +/- 14 GmM/M2 , P less than 0.05 and P less than 0.001, respectively) but only the high shunt group had a significantly lower peak systolic pressure (94 +/- 12 mm Hg vs. 109 +/- 11 mm Hg for control patients, P less than 0.01). There was no significant difference between the control and ASD groups in LV end-diastolic, mean right atrial, right ventricular end-diastolic, and pulmonary pressures. External systolic time intervals were compared in 5 control and 12 ASD patients. There was no significant difference between the two groups of patients in absolute values or indices for pre-ejection period, ejection time, or electromechanical systole. However, the ratio of the pre-ejection period index to left ventricular ejection time index (PEPI/LVETI) was significantly higher in ASD patients (P less than 0.05). In young subjects with large shunt ASD, certain indicators of left ventricular function are depressed. Evaluation of PEPI/LVETI may allow noninvasive determination of LV function.

Adolescent↗