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Biomedical subjects

M Berti

Publications and source records attributed to M Berti.

122 records · Page 7Linked to original sources
PubMed1977

The mechanism of action of nitro-heterocyclic antimicrobial drugs. Primary target of 1-methyl-2-nitro-5-vinylimidazole is DNA.

The antimicrobial drug 1-methyl-2-nitro-5-vinylimidazole (MEV) preferentially blocked DNA synthesis, was mutagenic and induced coliphage lambda in Escherichia coli. The antibacterial effects of MEV are the consequences of repairable damage to DNA, as shown by hypersensitivity of recA and uvr strains to MEV and related drugs, stimulation by MEV of DNA turnover which was dependent on the product of the uvrA gene, and the presence of cross-links in DNA from MEV-treated bacteria.

Anti-Bacterial Agents↗
PubMed1977

Studies of binding C3-substitute rifamycins to human and bovine serum albumin.

The interactions of a series of C3-substituted rifamycins with human and bovine serum albumins were studied in order to find possible correlations between the degree of binding and the structural features of the various molecules. The results obtained indicate some of the physicochemical properties and, therefore, of the structural requirements which appear to determine or influence the bonding mechanisms of this series of rifamycins. Two types of interaction were found to exist, ionic and hydrophobic types. The findings suggest that the inhibition by protein of the antibacterial activities of these antibiotics depends on the type of bonding mechanism rather than the degree of binding.

Chemical Phenomena↗
PubMed1977

Synthesis and biological activities of some 7-(1,2,4-oxadiazolylacetylamino) cephalosporins.

The synthesis and the physico-chemical properties of cephalosporin derivatives carrying an (1,2,4-oxadiazol-3-yl)- or (1,2,4-oxadiazol-5-yl)acetylamino moiety in position 7 are described. The effects of the presence of an amino or hydroxyl group on the oxadiazole ring are examined. Selected heterocyclicthiomethyl substituents are also introduced in the 3 position of the cephalosporin nucleus. In vitro antimicrobial activity and effectiveness in protecting against bacterial infection in the mouse are evaluated. Only compound (V b) was found to have slight activity when compared with cephalosporins in clinical use.

Acylation↗
PubMed1976

Gardimycin, a new antibiotic from Actinoplanes. III. Biological properties.

The new antibiotic gardimycin has an interesting in vitro antibacterial activity against Gram-positive bacteria and Neisseria gonorrhoeae. Parenteral administration gives a high degree of protection against experimental infections in mice. It also shows some chemotherapeutic activity when given rectally.

Actinomycetales↗
PubMed1973

Relationships between curing of the F episome by rifampin and by acridine orange in Escherichia coli.

Subinhibitory doses of rifampin cured F(+)Escherichia coli cells from the episome. The target of the drug was transcription because E. coli mutants with a ribonucleic acid polymerase resistant to rifampin were not cured. The experimental conditions required for optimal curing with rifampin very closely resembled those required for curing with acridine orange. Mutants were found which are more resistant to curing by both acridine orange and rifampin. Probably the two drugs affect a common metabolic step, or alternatively they may inhibit the synthesis of a factor which is necessary for the replication of the episome.

Acridines↗
PubMedDate not supplied

Does aggregation substance of Enterococcus faecalis contribute to development of endocarditis?

Aggregation substance (AS) of Enterococcus faecalis which is encoded by so-called sex pheromone plasmids enables the bacteria to bind to in vitro-cultured pig kidney tubular cells. It is reported that the presence of AS is not of pivotal importance for the ability of E. faecalis to cause infective endocarditis (EN). The lines of evidence for this are twofold: 1) sex pheromone plasmids and, therefore, the gene for AS were not present more often in epidemiologically unrelated strains of E. faecalis isolated from human cases of EN than in isolates from well-water (26 vs. 18%); 2) the presence of the adhesin did not correlate with the establishment of EN in an animal (rat) model. The data are discussed with respect to the specificity of interaction of AS with eukaryotic cells and the results of other studies.

Adhesins, Bacterial↗
PubMedDate not supplied

A new formula for echo-Doppler estimation of right ventricular systolic pressure.

The Doppler formulas currently used for right ventricular systolic pressure (RVSP) evaluation include right ventricular-right atrial (RV-RA) gradient and RA pressure. The former is expressed by the velocity of the trans-tricuspid regurgitant flow; the latter is generally assumed and is different from one formula to another. In 110 patients with cardiac disease with normal or elevated pulmonary pressure, we tested a new echo-Doppler formula for the evaluation of RVSP based on the estimation of RA pressure by means of the inferior vena cava collapsibility index (IVCCI) and compared this method with two traditional formulas (methods A and B) and with cardiac catheterization values. Patients were classified into three groups on the basis of IVCCI (group 1 > 45%, group 2 between 35% and 45%, and group 3 < 35%). RVSP was evaluated by method A (RV-RA gradient + 10), method B (RV-RA gradient x 1.1 + 14), and our new method, method C, which assigns 6, 9, and 16 mmHg to RA pressure in the presence of normal (> 45%), moderately reduced (between 35% and 45%), or markedly reduced (< 35%) IVCCI, respectively. IVCCI correctly identified RA pressure in the three groups (group 1, 6.8 mmHg; group 2, 10.8 mm Hg; and group 3, 13.1 mmHg); a high correlation existed between Doppler-derived and invasively determined RV-RA gradient (r = 0.99). Method C improved noninvasive estimation of RVSP in groups 1 and 3 compared with the other methods; in group 2, Doppler estimation of RVSP by methods A and C were comparable, whereas method B significantly overestimated the actual values.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Function, Right↗
PubMedDate not supplied

Effects of speed of intrathecal injection on unilateral spinal block by 1% hyperbaric bupivacaine. A randomized, double-blind study.

BACKGROUND: To evaluate if the speed of intrathecal injection affects the lateral distribution of spinal block during unilateral spinal anaesthesia with 1% hyperbaric bupivacaine. METHODS DESIGN: prospective, randomized, double-blind study. SETTING: anaesthesia Department at a University Hospital. PATIENTS: 30 ASA physical status I-II patients, scheduled for elective orthopedic surgery involving one lower limb only (ankle and foot surgery). INTERVENTIONS: after placing the patients in the lateral decubitus position with the site to be operated on dependent, dural puncture was performed at L3-L4 interspace using a 25-Gauge Whitacre spinal needle. After the needle hole had been turned toward the dependent side, patients were randomized to receive 8 mg of 1% hyperbaric bupivacaine injected over either 40 sec (Group SLOW, n = 15) or 3 sec (Group FAST, n = 15). The lateral position was maintained for 15 min. MEASUREMENTS: a blind observer evaluated the evolution of sensory (pinprick test) and motor (modified Bromage scale) blocks on both the dependent and nondependent sides until the regression of motor block by one degree. RESULTS: No differences in the maximal sensory level on both the dependent and nondependent sides were observed in the two groups. Unilateral sensory block was onserved in 6 patients in group SLOW (40%) and in 5 patients in group FAST (33%), (p = not significant[NS]. Unilateral motor block was observed in 9 patients in group SLOW (60%) and in 10 patients in group FAST (66%) (NS). CONCLUSIONS: Extremely reduced speeds of intrathecal injection did not improve the lateral distribution of spinal block when injecting 8 mg of 1% hyperbaric bupivacaine through a pencil-point directional spinal needle.

Adult↗
PubMedDate not supplied

A prospective, randomized comparison of dexketoprofen, ketoprofen or paracetamol for postoperative analgesia after outpatient knee arthroscopy.

BACKGROUND: This prospective, randomized study was conducted to evaluate the quality of postoperative pain relief when using dexketoprofen, ketoprofen, or paracetamol after outpatient knee arthroscopy. METHODS: Without premedication, 45 ASA physical status I-II patients undergoing elective outpatient knee arthroscopy with combined sciatic-femoral nerve block, were randomly allocated to receive either 25 mg oral dexketoprofen (n = 15), 50 mg oral ketoprofen (n = 15), or 500 mg oral paracetamol (n = 15) before block placement. After completion of surgery the same pain medication was given according to standard protocols, while 50 mg oral tramadol were allowed as rescue analgesic if required by the patient. After standard discharge criteria had been fulfilled, patients were discharged from the day-surgery unit, while a telephone follow-up was performed the day after surgery using standard questionnaires evaluating the quality of pain relief during the first 24 hours after surgery. Total consumption of rescue tramadol, maximum pain complained of after hospital discharge, as well as the visual analogue scale of pain measured at hospital discharge were assessed by an independent trained observer. RESULTS: No differences in anthropometric variables, duration of surgical procedure, and fulfillment of discharge criteria were observed between the three groups. The degree of pain measured at rest at hospital discharge was similar in the three groups, while the VAS measured during motion was higher in patients receiving paracetamol (24 +/- 2.5 mm) than in those patients treated with dexketoprofen (13 +/- 6 mm) or ketoprofen (17 +/- 5 mm) (p = 0.016). Two patients (one in ketoprofen group and one in paracetamol group) required rescue tramadol after hospital discharge; however, no differences in maximum pain complained of after surgery or patient acceptance were observed between groups. CONCLUSIONS: This prospective, randomized study demonstrated that in outpatients receiving arthroscopic knee surgery, the use of 75 mg/day dexketoprofen was as effective and safe as 150 mg/day racemate ketoprofen, with a better pain relief during motion compared to 2 g/day paracetamol when patients were discharged from the day-surgery unit.

Acetaminophen↗
PubMedDate not supplied

[Correlation of the lipophilicity of the active agents with their topical anti-inflammatory activity].

The present study concerns the relation between the therapeutic activity of some FANS in formulation for topical use and their lipophylic nature. The efficacy of topic formulations of three widely used FANS: cinnoxicam, piroxicam and diclofenac have been evaluated through the decrease of plantar edema induced by egg's white in the rat's hind paw. The volume increases after one hour were 55% in the group of rats treated with cinnoxicam, 64% in the animals treated with piroxicam and 79% in those treated with diclofenac, against 86% of control group. The partition coefficient (P) of the three active drugs have been detected. The P found for the three drugs 4.9, 3.3, 0.9 respectively demonstrate the direct correlation between the pharmacological activity of the topic formulation and its lipophylic nature.

Administration, Topical↗
PubMedDate not supplied

Block distribution and cardiovascular effects of unilateral spinal anaesthesia by 0.5% hyperbaric bupivacaine. A clinical comparison with bilateral spinal block.

BACKGROUND: A low dose of hyperbaric local anaesthetic solution, pencil point needle and slow speed of intrathecal injection have been reported to obtain a unilateral distribution of spinal anaesthesia. This should also minimize cardiovascular effects of spinal block. The aim of this prospective, randomized, parallel group study was to evaluate cardiac performance during unilateral subarachnoid block and to compare it with that produced by standard bilateral spinal anaesthesia. METHODS: With Ethic Committee approval and patients' consent we studied 30 ASA I-II patients scheduled for one leg surgery. Dural puncture was performed by 25-G Whitacre needle with patients lying in the lateral position and the side to be operated on dependent. Patients then randomly received 8 mg of 0.5% hyperbaric bupivacaine injected over 80 sec with needle hole orientated towards the dependent side (Unilateral, n = 15), or 15 mg of the same solution injected over 6 sec with needle bevel cranially directed (Control, n = 15). Only patients of the Unilateral group remained in the lateral position for 15 min. Noninvasive Arterial blood pressure, heart rate, stroke volume index and cardiac index were measured before spinal block (baseline) and then at 5, 15, 30 and 45 min; while sensory and motor blocks were evaluated at 15, 30 and 45 min on both sides. RESULTS: Unilateral spinal anaesthesia was observed in 11 patients of the Unilateral group (73%). Three patients of the Control group (20%) required colloids for intraoperative hypotension. Mean arterial blood pressure and heart rate decreased from baseline only in the Control group (p = 0.001 and p = 0.0003 respectively), while heart rate was decreased in Control even when compared to Unilateral group (p = 0.01). The stroke volume index was unchanged in the two groups (p = 0.22), while the cardiac index showed a 15-20% decrease from baseline in Control group (p = 0.001), with a significant decrease at 30 and 45 min when compared to Unilateral (p = 0.01). DISCUSSION: The use of 8 mg of 0.5% hyperbaric bupivacaine slowly injected through a directional needle provided a spinal block relatively restricted to the operative side with minimal effects on cardiovascular homeostasis.

Aged↗
PubMedDate not supplied

Incidence of hypotension and bradycardia during integrated epidural/general anaesthesia. An epidemiologic observational study on 1200 consecutive patients. Italian Study Group on Integrated Anaesthesia.

BACKGROUND: Combined epidural/general anaesthesia might theoretically emphasise the cardiovascular effects of epidural block alone. The goal of the present investigation was to evaluate the incidence of both hypotension and bradycardia during integrated epidural/general anaesthesia in a multicentric, observational study. METHODS: The incidence of clinical hypotension (systolic arterial blood pressure decrease by 30% or more from baseline), and bradycardia (heart rate < 50 beats/min) and other side effects have been evaluated in 1200 consecutive patients receiving integrated epidural/general anaesthesia. The time from induction of epidural anaesthesia to induction of general anaesthesia was considered as preoperative; while the time after general anaesthesia induction was considered as intraoperative. RESULTS: Preoperatively hypotension developed in 85 patients (2.8%), and bradycardia in 54 patients (4.5%). Intraoperatively, hypotension was observed in 380 patients (31.6%), and bradycardia in 153 patients (12.7%). Hypotension and bradycardia were not influenced by the type of surgical procedure, the type of maintenance of general anaesthesia (inhalational versus total intravenous general anaesthesia) and the level of epidural block (lumbar versus thoracic); but they were more frequent in patients with ASA physical status II and III-IV compared to patients with ASA physical status I (p < 0.05). Prophylactic volume preload decreased the incidence of hypotension from 41.5% to 22.4% (p < 0.0001), while prophylactic atropine before epidural block did not affect the incidence of bradycardia. Patients receiving epidural clonidine showed an increased incidence of intraoperative bradycardia compared to those who did not receive it (p < 0.0001). DISCUSSION: Randomized, controlled studies should be advocated in order to compare the incidence of hypotension and bradycardia during integrated anaesthesia and during epidural block alone. Our results demonstrated that the use of integrated epidural/general anaesthesia produces an incidence of perioperative hypotension and bradycardia similar to that reported when central blocks are used alone.

Adult↗