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Biomedical subjects

M E Clementi

Publications and source records attributed to M E Clementi.

26 records · Page 2Linked to original sources
PubMed1991

Antibodies against small molecules.

Compounds with low molecular weight (haptens) are not usually immunogenic. Thus, an hapten should be conjugated with a carrier protein therefore immunizing an animal, in order to induce a strong immune response and in turn obtain large amount of antibodies. Suitable macromolecules are usually albumins, thyroglobulins, haemocyanins and polylysine. The production of specific antibodies against haptens is important both for assays of hormones and drugs in biological fluids or for therapeutic applications in tumour therapy. Approaches in choice of both carrier protein and conjugation methods will be described.

Animals↗
PubMed1990

Flight and heat dissipation in birds. A possible molecular mechanism.

Birds during normal sustained flight must be able to dissipate more than 8 times as much heat as during rest in order not to be overheated. The experiments reported in this note on the hemoglobin systems from two different birds indicate the existence of a molecular mechanism by which hemoglobin is used simultaneously for oxygen transport and heat dissipation.

Animals↗
PubMed1990

Differences between horse and human haemoglobins in effects of organic and inorganic anions on oxygen binding.

Despite the fact that the horse is one of the more common domesticated animals, there are few reports dealing with the properties of its blood, and no comprehensive study has been performed on the reactivity of horse haemoglobin towards organic and inorganic ions. Here we report data on the effects of the organic phosphates D-glycerate-2,3-bisphosphate (2,3-DPG) and InsP6, and of chloride on the properties of horse haemoglobin. Thus the effect of saturating concentrations of 2,3-DPG on the oxygen affinity of horse haemoglobin is about 60% lower than with human adult haemoglobin under the same experimental conditions. The same applies also to InsP6, whose effect on oxygen binding to horse haemoglobin is decreased by about 55% compared with human adult haemoglobin. On the whole, horse haemoglobin appears to be much less sensitive to organic phosphates than previously believed. These results are discussed in the light of the primary structure of the molecule.

2,3-Diphosphoglycerate↗
PubMed1990

Arctic adaptation in whale hemoglobin: interplay of carbon dioxide and temperature in the oxygen unloading.

The functional properties of hemoglobin from the whale Balaenoptera acutorostrata have been characterized as a function of pH, CO2, organic phosphates and temperature. Carbon dioxide effect does not depend on the presence of organic phosphates such as 2,3-DPG and P6-inositol while it is strongly affected by temperature, so that at 37 degrees C it is completely abolished. This, together with the very small delta H of oxygen binding (delta H = -4 to -2 Kcal/mol of oxygen at pH 7.4) has been physiologically interpreted on the basis of the specific metabolic needs of fins and tail which are the place of a great muscular activity.

Adaptation, Physiological↗
PubMed1990

Lactate does facilitate oxygen unloading from the hemoglobin of the whale, Balaenoptera acutorostrata, after diving.

The present study reports on a specific effect of lactate on the oxygen binding properties of the hemoglobin from the whale, Balaenontera acutorostrata. In fact 0.1 mM lactate may increase the amount of oxygen unloaded to the tissues as much as 30%. Under these conditions the Bohr shift, of the magnitude of about -1, does not alter the oxygen affinity, but plays an important role in the isohydric transport of carbon dioxide.

Animals↗
PubMed1989

Arctic life adaptation--III. The function of whale (Balaenoptera acutorostrata) hemoglobin.

1. The oxygen binding properties of the hemoglobin from the Lesser Rorqual, Balaenoptera acutorostrata, has been investigated with respect to the possible effects of organic phosphates on gas transport in arctic environments. 2. The intrinsic oxygen affinity of the hemoglobin is high and strongly modulated by the effects of organic phosphates. 3. In the absence of organic phosphates, the temperature sensitivity of oxygen binding expressed by the heat of oxygenation, delta H, is -16.2 kcal/mol when corrected for the heat of oxygen in solution. 4. In the presence of organic phosphates there is a marked decrease in the temperature sensitivity delta H approximately -5 kcal/mol). 5. This feature is of great importance for oxygen unloading in the flippers and the tail, where the temperature is lower than the trunk of the whale. 6. Furthermore the organic phosphates strongly increase the Bohr coefficient, delta log P50/delta pH, from less than -0.3 in stripped hemoglobin to about -1.5 when the hemoglobin is saturated with P6-inositol. 7. This feature may be of great physiological importance by reducing the CO2 tension and acidosis after a prolonged dive.

Adaptation, Physiological↗