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Biomedical subjects

C David

Publications and source records attributed to C David.

At least 55 records · Page 3Linked to original sources
PubMed1988

[In vitro effect of combinations of netilmicin and amikacin with fosfomycin and pefloxacin on 31 strains of heterogeneous methicillin- resistant Staphylococcus aureus].

The Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) of 31 strains of Staphylococcus aureus resistant to methicillin and gentamicin were determined towards aminoglycosides: netilmicin (N) and amikacin (A). The results of the study showed a large discordance between the technic using dilution in Mueller-Hinton broth and the technic using agar diffusion with antibiotic discs. The level of sensitivity appears to decrease by dilution. The problem of using these aminoglycosides in combination with other antibiotics as fosfomycin (F) and pefloxacin (P) was faced. In vitro, antibacterial activity of combinations [N-F], [N-P] and [A-F], [A-P], was studied by microtiter checkerboard method. The antibacterial effects of these combinations were evaluated by determination of Fractional Bactericidal Indices (FBC-indices). The combination netilmicin or amikacin with pefloxacin has an additive bactericidal effect in most cases, without discrimination between the different aminoglycosides (FBC #0.82). Netilmicin or amikacin in combination with fosfomycin are found to be additive or moderately synergistic (FBC #0.53). No occurrence of antagonism was observed.

Amikacin↗
PubMed1984

Phase I study of immunotherapy by live Brucella abortus (strain 19 BA) in cancer patients.

Twenty-eight patients showing negative responses against Brucella antigens were included in a preliminary trial of immunotherapy by a live Brucella abortus vaccine. Seventeen patients had squamous cell lung carcinoma, eight had acute myeloid leukemia, and three were classified as "others." Brucella abortus strain 19 BA was administered sc in a single injection at doses ranging from 5 X 10(7) viable organisms to 10(10), ie, 40 times the usual vaccine dose. No important toxicity was noted. Edematous reactions at the injection site and febrile responses were infrequent and moderate, hemocultures were all negative, spleen volume did not vary significantly, and cbc showed an increase of polymorphonuclear cells and lymphocytes.

Blood Cell Count↗
PubMed1983

Influence of the culture conditions of Brucella abortus on its antitumor properties.

A heat-inactivated rough mutant of B. abortus increased resistance to a transplantable lymphoma when cultured on solid agar (ag) but not when cultured on a fluid medium (fl). The ag organisms were smaller, more toxic and induced more interferon 2 h after injection than fl. They also contained a phospholipid (cardiolipin) absent from fl preparations.

Animals↗
PubMed1983

[Effects of prolonged consumption of lactose or hydrolyzed lactose in the rat. 5. Intestinal metabolism of glucose and galactose].

Effect of Prolonged Consumption of Lactose or Hydrolyzed Lactose in Rats.--5. Intestinal Metabolism of Glucose and Galactose. The intestinal metabolism of galactose is different according to the form of ingestion. With a lactose diet (L), the galactose is abundant in intestinal contents (Tab. I), since neither the intestinal flora (Tab. II), nor the epithelial tissue (Tab. III) can easily metabolize the galactose. The glucose disappears more rapidly than the galactose (Tab. I). With a hydrolyzed lactose diet (LH), the intestinal contents of two hexoses are identical (Tab. I). In this case, the enzymic activity of epithelium metabolizes an amount of galactose 6 times as big as with the lactose diet (Tab. III).

Animals↗
PubMed1983

Structure of T-DNA in roots transformed by Agrobacterium rhizogenes.

DNA isolated from hairy roots incited on Daucus carota by Agrobacterium strains harboring the Ri plasmid was probed with Ri plasmid fragments to identify plasmid sequences transferred and integrated into the plant genome. One hairy root line was incited by an A. rhizogenes natural isolate strain harboring two large plasmids in addition to the Ri plasmid. DNA from hairy roots incited by this strain contained a total of five nonidentical copies of T-DNA which together comprised a T-DNA complement representing a 34-42 kb segment of the Ri plasmid. A second hairy root line was incited by a Ti plasmidless A. tumefaciens strain into which the Ri plasmid had been conjugated. Hairy root DNA incited by this strain contained four identical T-DNA copies 17-18 kb in length and one truncated copy. T-DNA borders occurred at preferential sites of the Ri plasmid. T-DNA structure in these hairy root lines is similar to T-DNA structure in tumors incited by Ti plasmids of A. tumefaciens.

DNA↗
PubMed1982

[Intestinal absorption of glucose and galactose in the rat determined by blood hexose].

Adult rats are used to consume their diet within the space of 30 min. They are sacrified after fasting 2 hours or 30 to 90 min. after the end of meal. Blood sugars are determined. -- The administration of galactose (GAL group) at 40 p. 100 of the diet induces a high postprandial galactosemia (near 600 mg p. 100 ml) without glycemia change: the absorbed galactose is not converted into glucose. -- The consumption of glucose-galactose mixture (G-G group) don't induce postprandial hyperglycemia. However, galactosemia is about 250 mg p. 100 ml. In our conditions, glucose and galactose seem absorbed by two different systems. The galactose absorption would be favoured; otherwise, the absorbed glucose would be partly epimerized into galactose. Galatitolemia goes on 24 hours after the meal but it is not immediately modified by the galactose consumption. The galactosemia and galactitolemia variations are independent one of the others.

Animals↗
PubMed1982

[Effect of prolonged consumption of lactose or hydrolyzed lactose in the rat. 2. Digestibility, retention and utilization of lactose components].

Nutritional balances are made with groups of 12 rats Wistar receiving well-balanced diets with 40 p. 100 of sucrose (T), or 40 p. 100 of lactose (L and P), or hydrolyzed lactose (LH and PH). Whey (L) and ultrafiltration permeate (P) are used in crude state or after enzymic industrial lactase hydrolysis (LH and PH). The animals consume diets during eight months. Faeces contain neither lactose nor galactose, but glucose in small quantities. In all urines occurs about 0,5 mg/day of glucose. The lactose diets (L and P) provoke a week lactosury (0,36 p. 100 of ingestion). Galactose and galactitol are abundant in urines: with lactose diets (L and P), the urinary excretion is equal to 4 p. 100 of ingested galactose. In urines of hydrolyzed lactose diets (LH and PH) the excretion reaches 26 p. 100 of ingestion. In this case the excretion is remarkably invariable from third day of eighth month: the urinary galactose corresponds to 23 p. 100 and galactitol to 3 p. 100 of consumed galactose. The urines of lactose diets (L and P) and hydrolyzed lactose diets (LH and PH) contain 100 and 300 mg/day of non sugar reducing substances respectively, i.e. 40 p. 100 of total urinary reducing power. The apparent retention of lactose (L and P) is 95,5 p. 100 and that of the hydrolyzed lactose (LH and PH) is 86 p. 100 after 8 months of experiment but it is estimated that digestive flora consumes 40 p. 100 of dietary lactose (L and P).

Animals↗
PubMed1982

[Reactions in the rats from prolonged consumption of lactose or hydrolyzed lactose. 3. Crystalline lens].

Three groups of 15 rats Wistar receive a well-balanced diet with 40 per cent of sucrose (T), lactose (P) or hydrolyzed lactose (PH) in the form of ultrafiltration permeate. After 160 days, no cataract is revealed in the T and P groups. In the PH group, 14 rats reached by cataracts in both eyes: it is slightly developed (PH 2), mildly developed (PH 3) or practically total (PH 4). The inositol disappearance, the high quantity of galactitol, the water and sodium increases are the factors observed before the lens opacification and are responsible for the cataract. Then, during the opacification, soluble proteins, potassium and hydratation of the lens decrease. Galactose 1-P is slowly formed before and during the lens opacification. The lens of the P group (lactose) differ from the control group (T) by the nature and the quantity of hexitols, only.

Animals↗
PubMed1981

Interleukin 2, production in the syngeneic mixed lymphocyte reaction.

In the syngeneic mixed lymphocyte reaction, Ly 1 cells proliferate following stimulation with Ia-positive macrophage-like cells. The proliferation is accompanied by the release of interleukin 2 into the medium. Both the proliferation and interleukin 2 production are dependent on the expression of Ia antigenic determinants, as the addition of haplotype-specific anti-Ia antisera to the cultures inhibits both parameters.

Animals↗
PubMed1981

Tryptic peptide comparison of Ia antigen alpha and beta polypeptides from the I-A mutant B6.C-H-2bm12 and its congenic parental strain B6.

Previous studies of the B5.C-H-2 bm12 (bm12) strain have demonstrated the presence of a mutation localized to the I-A subregion of the mouse H-2 major histocompatibility complex. This mutation has been shown to be responsible for defects in Ir-gene function in Ia and MLR determinants. A comparison of the molecular size of the bm12 mutant and the parental B6 Ia-antigen component polypeptides failed to demonstrate any differences in the alpha and beta polypeptides. Thus, no major structural additions for deletions are present in the Ia alpha and beta chain polypeptide or carbohydrate structure. A significant decrease in the amount of invariant (31K) polypeptide was, however, consistently observed in the bm12 Ia antigen preparations. Tryptic peptide comparisons of 14C B6 and 3H bm 12 alpha and beta polypeptides demonstrated a limited number of peptide differences in the bm 12 beta polypeptide but none in the bm12 alpha polypeptide. The significance of these biochemical mutations and altered biological phenomena are discussed in relation to a model of the immunological interaction sites on Ia antigens.

Animals↗
PubMed1980

[Effect of prolonged consumption of lactose or hydrolyzed lactose in rats--nutritive efficiency and anatomical changes (author's transl)].

Growing rats receive for 270 days well-balanced diets with 40 p. 100 of lactose or industrial hydrolyzed lactose. Whey and ultrafiltration permeate are used in crude state or after enzymic lactose hydrolysis. In lactose diets the ingesta and the food efficiency are considerably reduced as well as the growth. The water intake is greatly increased. The dry mater digestibility is not modified by the lactose after an experiment of 7 months. Hydrolyzed lactose provokes all these phenomena but with a weaker intensity. In a zootechnical point of view the lactose hydrolysis reduces the detrimental properties of lactose. After 270 days animals having received lactose show a high hypertrophy of small intestine and caecum tissues as well as a small renal hypertropy (dry matter/100 g of living weight). Hydrolyzed lactose involves the comparable modifications but with a less extent. Numerous facts attributed to lactose molecule are partially imputable to galactose molecule mainly the increase of water consumption. Only the growth of bone tissue (femur) is provoked by the lactose molecule itself and not to its components. When the diet is well-balanced the presence of whey proteins does not seem to modify the lactose effects.

Animals↗
PubMed1979

Genetic control of experimental autoimmune myasthenia gravis in mice. I. Lymphocyte proliferative response to acetylcholine receptors is under H-2-linked Ir gene control.

As a first step in determining the genetic control of experimental autoimmune myasthenia gravis in mice, we tested the proliferative responses of lymph node cells to torpedo acetylcholine receptors (TAR). Studies with congenic and recombinant inbred strains of mice revealed that T-cell responses to TAR are controlled by an H-2 linked Ir gene, mapping in the I-A subregion of mouse major histocompatibility complex.

Acetylcholine↗