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Biomedical subjects

E Marchi

Publications and source records attributed to E Marchi.

33 records · Page 2Linked to original sources
PubMed1987

Comparison between sulbenicillin and piperacillin levels in serum and in bronchial secretions--a pharmacokinetic study.

In order to assess pharmacokinetic differences between sulbenicillin (S) and piperacillin (P), two penicillin derivatives, 24 in-patients, 12 males and 12 females mean age 59.4 years, suffering from recurrent bronchial infections were enrolled. Patients were randomly allocated to S (12 patients) and to P (12 patients) and were given 2 g i.m. every 12 h of the awarded antibiotic, for a 7-day period. At the first and 7th day blood samples (0.25, 0.5, 1, 2, 4, 6, 8 and 12 h after dosing) as well as sputum samples (1, 2, 4, 8, 12 h after dosing) and urine samples (3, 6, 9 and 12 h after dosing) were collected, and the levels of S or P were determined by bacillus subtilis test. The pharmacokinetic analysis was performed by a standard program. On day 1 and 7 the mean peak serum concentration occurred at the first hour for S (39.9 +/- 5.2; 40.9 +/- 5.1 mcg/ml, respectively) and for P (32.2 +/- 5.4; 33.1 +/- 5.4 mcg/ml, respectively). Serum AUC0-12 and AUC0-00 (mg/l.h) levels of S were significantly higher (p less than 0.01 or less) than those of P on day 1 and 7. Similarly MRT (8 h) and Cmax (mg/l) where higher but only on day 7. Sputum AUC0-12 (mg/l.h) level of S was significantly higher (p less than 0.05) than that of P on day 1 and 7. In conclusion serum and sputum S appear to have a different pharmacokinetic profile in respect to P. However, when compared to the AUC, both drugs reach antibacterial levels.

Aged↗
PubMed1987

Some aspects of "deep lung" cellular immunity in chronic bronchitis before and after therapy with tiopronin.

Fifteen patients suffering from obstructive chronic bronchopneumonia in a clinical steady-state phase received 0.6 g of tiopronin once a day during 10 days per os. The lymphocyte subsets (OKT3, OKT4 and OKT8) have been identified in peripheral blood and in bronchoalveolar lavage liquid (BAL) before and after treatment and phagocytosis has been evaluated in pulmonary alveolar macrophages (PAM) (phagocytosis index, phagocytosis percentage, superoxide-ion production). A highly significant improvement in the phagocytosis process has been observed in the PAM, as well as an increase in the number of lymphocytes T3 and in the T4/T8 ratio (due to an increase in T4 lymphocytes) in the BAL; while in peripheral blood T3 and T4 lymphocytes and the T4/T8 ratio only showed a nonsignificant increase after treatment. The possible mechanisms on which these variations are based have been investigated.

Aged↗
PubMed1986

In vitro and in vivo evaluation of L/105, a new topical intestinal rifamycin.

L/105 (4-deoxy-4'-methylpyrido [1',2'-1,2] imidazo [5,4-c] rifamycin SV; INN: Rifaximin) is a new rifamycin active in vitro against both gram-positive and gram-negative microorganisms. The activity of L/105 was comparable to that of rifampicin and, against gram-positive bacteria, higher than that of neomycin. The antibacterial activities of L/105 and rifampicin were equally affected by the highest size of inoculum used (10 cells/ml) and they were equally bactericidal against Staphylococcus aureus and Escherichia coli. The speed and the degree of development of resistance to L/105 were quite superimposable on those of neomycin. In vivo, L/105 did not show therapeutic activity by oral route in the staphylococcal infection in the mouse till the highest dosage used (10 mg/kg b.w.); under the same conditions, gentamicin was equally ineffective. After subcutaneous administration, L/105 showed therapeutic activity (ED50 = 0.46 mg/kg b.w.) practically superimposable on that of orally administered rifampicin.

Administration, Oral↗
PubMed1985

4-Deoxypyrido[1',2':1,2]imidazo[5,4-c]rifamycin SV derivatives. A new series of semisynthetic rifamycins with high antibacterial activity and low gastroenteric absorption.

A series of 4-deoxypyrido[1',2':1,2]imidazo[5,4-c]rifamycin SV derivatives (6-11) were prepared that demonstrated high antibacterial activity suitable for an intestinal disinfectant. These compounds are zwitterionic in nature and are poorly absorbed through the gastroenteric tract but maintain the ability to cross the bacterial cell wall. X-ray crystallographic data are presented to demonstrate the zwitterionic nature of these compounds. The structure-activity relationship of this novel series of antibiotics is discussed and the derivative with the highest ratio between subcutaneous and oral activity (6) was selected for clinical development. At the outset of this work several 3-(quaternary ammonium bromides) (1-5) were prepared and tested for antibacterial activity. These compounds were demonstrated to be too polar to even cross the bacterial cell wall but led to the synthesis of 6-11.

Animals↗
PubMed1985

A study of structure-activity relationships in 4-deoxypyrido[1',2'-1,2]imidazo[5,4-c]rifamycin SV derivatives by electron spectroscopy for chemical analysis and 1H NMR.

A new class of rifamycins, 4-deoxypyrido[1',2'-1,2]imidazo[5,4-c]rifamycin SV derivatives, has been synthesized. They are potent antibacterial agents and are not absorbed at the gastrointestinal level and can therefore probably be used as antibacterial intestinal disinfectants. From the present X-ray, electron spectroscopy for chemical analysis, and 1H NMR study, it appears that this peculiar pharmacokinetic behavior is mainly to be attributed to the fact that the pyridoimidazo system exists in these compounds in a mesomeric betaine form, bearing one positively and one negatively charged nitrogen. If it is assumed that rifamycins are generally absorbed by passive diffusion, the presence of the two oppositely charged nitrogens, together with the presence of the phenolic hydroxyls, means that these molecules are ionized at all pH values encountered along the gastrointestinal tract, which thus prevents their absorption. These molecules also display a strong tendency to self-associate both in solution and in the solid state, and the increase in molecular size may also play a role in preventing their absorption.

Magnetic Resonance Spectroscopy↗
PubMed1977

Synthesis and antibacterial activity of some derivatives of tolypomycinone. Relationship between structure and activity in ansamycins.

3-Aminotolypomycinoes and 3,16-diamino-16,17-dihydrotolypomycinones are formed by the addition of primary and secondary amines to tolypomycinone, obtained by mild hydrolysis of the antibiotic tolypomycin Y.3-Amino-16,17-dihydrotolypomycinones are formed by the addition of primary and secondary amines to 16,17-dihydrotolypomycinone. In vitro microbiological tests showed high antibacterial activity in compounds obtained by the addition of primary amines, which must be unbranched in the alpha position to the nitrogen atom to position 3 of the naphthoquinone ring. The relationship between structure and activity is described, and evidence is presented that hydrogen bonding between the amino NH bonded to C3 and the amide CO of tolypomycinone is very important for biological activity.

Escherichia coli↗
PubMedDate not supplied

Low molecular weight heparin restores antithrombin III activity from hyperglycemia induced alterations.

Alteration of antithrombin III (ATIII) activity, glycemia level dependent, exists in diabetes mellitus. In this study the ability of a low molecular weight heparin (LMWH) (Fluxum, Alfa-Wassermann S.p.A., Bologna, Italy), as well as unfractioned héparin, to preserve ATIII activity from glucose-induced alterations, both in vitro and in vivo, is reported. The subcutaneous and intravenous LMWH and heparin administration increases basal depressed ATIII activity in diabetic patients. Heparin shows an equivalent effect on both anti-IIa and anti-Xa activity of ATIII, while LMWH is more effective in preserving the anti-Xa activity. Similarity, heparin preserves ATIII activity from hyperglycemia-induced alterations, during hyperglycemic clamp, and LMWH infusion is able to preserve a significant amount of anti-Xa activity from glucose-induced alterations. Since diabetic patients show a high incidence of thrombotic accidents, LMWH appears to be a promising innovation for the prevention of diabetic thrombophylia.

Adult↗