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Biomedical subjects

G Brule

Publications and source records attributed to G Brule.

At least 19 recordsLinked to original sources
PubMed2000

Simple rapid procedure for preparation of large quantities of ovalbumin.

A simple rapid procedure for preparation of large quantities of highly purified homogeneous ovalbumin from egg white by using an anion exchanger is described. It is based on the principle of frontal chromatography. The volume of "mucin-free" egg white loaded onto the column was determined in order to exceed resin capacity. Thus, competition between proteins for resin sites was created. Owing to its high negative charge density, ovalbumin drives other egg white proteins from the column progressively. Two hundred and fifty milliliters of Q-Sepharose FF gel eluted isocratically with 0. 5 M NaCl extracted 9.55 g of ovalbumin with a purity rate of 83%. A 6.75 g amount of ovalbumin, with a purity rate of 94%, was recovered with an isocratic elution program using 0.14 M NaCl. Purified ovalbumins were compared by electrophoresis and analytical chromatography with other ovalbumin preparations.

Chromatography, Ion Exchange↗
PubMed1994

Interaction between Ca2+ release from inositol trisphosphate sensitive stores and Ca2+ entry through neuronal Ca2+ channels expressed in Xenopus oocyte.

Rat cerebellar RNA injected into Xenopus oocytes leads to the expression of putative P-type voltage-dependent Ca2+ channels (VDCCs). The monitoring of intracellular Ca2+ variations by recording the Ca2+ dependent chloride current in voltage clamped oocytes indicates that activation of these Ca2+ channels by depolarization gives rise to two distinct components of cytosolic Ca2+ elevation. If the early component (T1) can be directly attributed to the Ca2+ entry through VDCCs, the second delayed one (T2) is related to a Ca2+ release from InsP3 sensitive stores activated following Ca2+ entry. Modifications of cytosolic Ca2+ by direct injection of Ca2+ into oocytes or by increasing the Ca2+ influx through VDCCs suggest that the Ca2+ release from intracellular InsP3 sensitive stores can be modulated in a differential manner. Namely, discrete elevations of cytosolic Ca2+ switch on the Ca2+ release whereas higher Ca2+ concentrations dampen the release. These results suggest a functional coupling between P-type VDCCs and InsP3 receptors.

Animals↗
PubMed1993

Positive regulation by protein kinase C of slow Na current in Xenopus oocytes.

The slow inward Na current observed during sustained depolarization of the Xenopus oocyte membrane is due to a complex mechanism described as the induction of the channels. The present work investigates the role of protein phosphorylation in Na channel function. Injection of alkaline phosphatase in the oocytes decreased inward current. Therefore, the possible involvement of protein kinase in Na channel induction was explored. Treatment of oocytes with two activators of protein kinase C (PKC) resulted in enhanced Na current amplitude, whereas the treatment of oocytes with two potent PKC inhibitors decreased the inward current. These results imply that PKC phosphorylation is a fundamental step of Na channel induction. The possibility that the depolarization of the oocyte membrane may be the factor involved in PKC activation is discussed.

Alkaloids↗
PubMed1981

[N-Methyl-9 hydroxy-ellipticine (NSC 264-137) in the treatment of malignant metastases. Preliminary results (author's transl)].

In a phase II trial 2 N-Methyl-9-Hydroxy-Ellipticine (NMHE) was administered in weekly infusions of 100mg/m2 over 1 hour to patients with malignant metastases. Prior to injection, the drug was dissolved in 250 ml isotonic glucose. The results were evaluated in 67 patients. Objective regression was observed in 23 (34%) and was superior to 50% in 10 cases. Patients showing signs of regression under treatment were mostly those with breast cancer (10/24 cases), soft tissue sarcoma (3/9 cases) and renal cancer (2/8 cases). The main toxic effect was haemolysis (2 cases), probably due to an immunoallergic mechanism. Attention is drawn to the lack of bone marrow toxicity.

Alkaloids↗
PubMed1980

[Influence of age on the secretion of gastric juice and electrolytes in the preruminant calf].

Four preruminant Friesian calves were fitted with an innervated abomasal fundic pouch cut from the lesser curvature. They were fed twice daily a milk substitute containing only spray-dried skim-milk powder as protein source. The daily outflow of gastric juice regularly increased from 400 to 1 800 g/day between 2 and 16 weeks of age and did not change later. The daily outflow/100 kg liveweight increased until 7 to 9 weeks of age and decreased later until 30 weeks (fig. 1). The pH of the secretion always ranged between 1 and 2, except during the days following surgery and when the calves were ill (fig. 2). Expressed in absolute terms, the total outflow of hydrogen, sodium, potassium and chloride ions increased with age; this was mainly due to the increase in the outflow of gastric juice since the ion concentration showed a cyclic pattern with age (fig. 3). When expressed on a liveweight basis, the daily ion output alternatively showed increasing and decreasing periods, mainly in relation to changes in concentration, but no significant trend with age was observed (fig. 4).

Abomasum↗
PubMed1980

[Pains in cancer patients (author's transl)].

Pain is a frequent and complex symptom in cancer patients. For successful treatment, it is necessary to recognize the exact origin. Pain is often the direct or indirect consequence of neoplastic spread to osseous or peripheral nervous tissues. But for one patient out of five, it is induced by previous treatments and rarely is unrelated to the cancer. Surgery, radiotherapy, hormonotherapy and chemotherapy often improve, temporarily at least, painful symptoms induced by tumor growth. For chronic persisting pain, the oncologist may use peripheral analgesics, anxiolytics, morphinics, local and neurosurgical treatment. Moreover the specific indications of each modality must be recognized and if necessary combined if the analgesic effect is inadequate or too brief.

Humans↗
PubMed1978

[Hydrolyzed lactose contained in the ultrafiltrate of milk or milk products in an enzymatic membrane reactor].

Milk and milk by-products with a low lactose content, very interesting from a nutritional and technological point of view, were obtained by the application of the enzymatic membrane reactor technique. A previous separation of the aqueous phase of milk or ultrafiltrate was necessary and realized by ultrafiltration. The enzyme, a commercial beta-galactosidase, was maintained in solution in the retentate part of the membrane reactor. The optimal conditions of the lactose hydrolysis in milk and whey ultrafiltrates were determined. The behaviour of the aqueous phase of milk in membrane reactor, specially of mineral salts, was studied. Three possibilities were proposed to avoid a calcium-phosphate deposit on the surface of (and in) the reactor membranes: a precipitation of calcium salts by heating, a partial demineralization by electrodialysis or ion exchange, a calcium complexation by addition of sodium citrate. A continuous process for the lactose hydrolysis of milk and demineralized whey or milk ultrafiltrate was proposed. The organoleptic quality of low lactose milk, before and after heat treatment, was evaluated by a tasting panel. High sweeting syrup, were obtained by concentration of lactose hydrolyzed and demineralized ultrafiltrates. Nutritional aspects of these products are discussed specially from the toxicological point of view of galactose.

Animals↗
PubMedDate not supplied

[Structure-activity relationship of a new family of calcium antagonist molecules derived from monosaccharides].

The Ca++ antagonist effects of new drugs derived from monosaccharides were tested in the rat duodenal muscle preparation in vitro. The structure-activity relationship shows that: 1. The monoacetonide products (nR-O-MAG and nR-S-MAG) with alkyl chain from 8 to 9 C atoms induce a maximal reduction of muscular tonus and contraction. 2. The inhibitory effect rapidly decreases when the alkyl chain has a number of C atoms smaller than 7 or larger than 9. 3. The diacetonide (DAG) and acetonide (G) products induce an inhibition of less extent. 4. The Ca++ antagonist effect is very slightly changed by the type of heteroatom (O or S) linking the alkyl chain to the monosaccharide. 5. The type of monosaccharide affects the Ca++ antagonist activity.

Animals↗