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Biomedical subjects

T Longo

Publications and source records attributed to T Longo.

At least 19 recordsLinked to original sources
PubMed1994

A comparison between the hemolytic and antibacterial activities of new quaternary ammonium polymers.

New quaternary ammonium polymers, which in a previous work had shown relevant antibacterial properties, have been investigated as regards to their hemolytic activity (HA) in comparison with a low molecular weight commercial antibacterial agent, Steramine G (SG). All polymers exhibit negligible, or at most modest, HA at dosages and contact times at which SG is strongly hemolytic.

Anti-Bacterial Agents↗
PubMed1994

[Peritoneal reactions caused by starch used regularly for lubricating surgical gloves. Review of the literature].

The contamination of the operating field by a number of substances including the starch used to lubricate surgical gloves is one of the causes of foreign body granuloma formation. The role of starch is particularly clearly documented in the peritoneal cavity where it may provide the basis of a well defined nosological phenomenon, "starch peritonitis", but it has also been reported in most other anatomical districts. The most logical solution to this problem is to use starch-free surgical gloves prepared using another type of lubricant without the aforesaid drawbacks. This paper analyses international clinical and experimental literature focusing on the damaging effects resulting from the introduction of starch into the peritoneal cavity.

Gloves, Surgical↗
PubMed1993

Biomechanical factors in abdominal aortic aneurysm rupture.

Hitherto the size of abdominal aortic aneurysms (AAA) has been considered the most important factor in determining the risk of rupture. For this reason most interest has been devoted to physical, echographic and tomographic analyses of the shape of AAA. However, it is known that rupture can also occur in small AAA. Other factors must be considered to have an important role in the natural history of aneurysms. The aim of this study was to characterise the mechanical stress in the wall of an AAA due to pressure in the presence of atherosclerosis, intraluminal thrombus and anatomical restraints. The Finite Elements Method (FEM) was used to determine wall stress distribution. Due to the simplicity of the AAA structure an axisymmetric model has been built. The results of the structural analysis confirms that maximum stress increases with diameter. These effects may be reduced by the presence of intraluminal thrombus, which in the models reduces maximum stress by up to 30%; however this is not the case for dissecting thrombus. On the other hand atherosclerotic plaques cause stress concentration and a significant increase in maximum wall stress. The risk of rupture can increase by about 200%. Finally the investigation shows the FEM is a versatile tool for studying the mechanics of vascular structures. It enables the influence of various parameters on wall stress to be quantified in diagnostic settings, and so could be useful for predicting the rupture of AAA, although at present such predictions are limited by data leakage and by the approximations used in the model.

Aged↗
PubMed1993

The association between abdominal aortic aneurysms and chronic leg ischaemia. Prevalence in 125 consecutive patients.

A study was carried out to see if in patients with atherosclerotic lesions of the lower limbs the percentage of abdominal aneurysms is higher than in the general population. One hundred twenty five consecutive patients were studied in two different hospitals and compared with a control group. In the two groups with peripheral vascular diseases the patients had a prevalence of aneurysms of 12%, while in the control group the prevalence was of 3%. All patients were operated on successfully except two of them who are now in follow up with regular ultrasound assessment, one with an aortic aneurysm of 3.2 cm and the other with an aortic diameter of 4 cm and moderate liver failure.

Aged↗
PubMed1991

[Importance of Staphylococcus epidermidis in the bacterial colonization of abdominal drains in surgical patients].

Bacterial adherence to biomaterials as an element of clinical relevance is a well-known factor in the pathogenesis of sepsis. Drainages, intravascular catheters, surgical prostheses and other devices are susceptible to bacterial colonization with clinical consequences. In the last few years attention has been paid to coagulase-negative Staphylococcus (S. epidermidis), mainly to some strains able to produce a highly adhesive polysaccharide substance, called glycocalix or slime. This promotes adherence either interbacterial either between bacteria and biologic tissues or synthetic materials acting as a pathogenetic factor in sepsis being able to increase bacterial resistance to phagocytes and antibiotics. Bacterial contamination of 40 abdominal drainage tubes in patients operated in elective and in emergency surgery for various pathology has been evaluated. Sonication of the tip of the drainage was utilized in order to promote the detachment of adherent colonies and its effectiveness was compared to that of microcentrifugation. Culture of 25 drainages (62.5%) showed no bacterial contamination; 7 drainages (17.5%) have proved to be colonized by S. epidermidis, in 4 cases the isolated strains were also methicillin-resistant, 2 of which slime-producing. Out of the 7 drainages colonized by S. epidermidis, 4 were removed from patients operated in emergency: none of the isolated strains was slime-producing. Six drainages (15%) were colonized by Gram+ bacteria (S. fecalis, P-sensible cocci, rods), 1 (2.5%) by E. coli and 1 (2.5%) by P. aeruginosa, S. epidermidis appears to be the chief contaminant of abdominal drainages, especially in emergency surgery; slime production has always been observed in methicillin-resistant strains: this confirms the hypothesis that slime production is typical of specialized, virulent strains.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1990

[Heterotopia of the gastric fundus wall in bilobate gallbladder associated with dilatation of the main bile duct. Description of a case].

On the basis of a recent case of fundic gastric heterotopia in the gallbladder, the principal, possible embryogenetic hypotheses of the malformation are described and discussed. The possibility that acid secretion of the gastric glands contained in the ectopic fundic mucosa determined part of the symptomatological and clinical picture accompanying signs of lithiasic cholecystopathy is also evaluated.

Adult↗
PubMed1988

Syphilitic aneurysm of the abdominal aorta: report of two cases.

We have described two histologically confirmed syphilitic abdominal aortic aneurysms arising below the renal arteries. Serological tests were negative and the patients had in the past been treated with penicillin and bismuth. We consider that there may be a correlation between atherosclerosis and syphilis in the natural history of some abdominal aortic aneurysms and the hazard of indiscriminate use of antibiotics for the treatment of other inflammatory vessel disease may allow syphilis to develop insidiously.

Aorta, Abdominal↗
PubMed1986

Ultrasound evaluation of atherosclerosis. Methodological problems and technological developments.

The evaluation of atherosclerosis requires the definition of the object to be measured and of the questions the investigation is required to answer. In the first part of this paper some of the problems that arise when planning and defining evaluation of atherosclerosis are discussed. The second part is a review of the principal methods based on ultrasound technology. The working principles and clinical applications of each method are discussed. The rationale of each type of instrument with respect to others is highlighted.

Arteriosclerosis↗
PubMed1985

Hemodynamic factors changing blood flow velocity waveform and profile in normal human brachial artery.

We have investigated the influence of changes of perfusion pressure and local peripheral resistance on blood flow velocity waveform and profile in normal human peripheral arteries. Blood flow velocity and profile were recorded from the distal end of the left brachial artery in ten normal subjects by means of an ultrasonic device. The records were obtained in basal conditions and after blood pressure in the brachial artery and local peripheral vascular resistance were changed, separately or together, by progressive inflation of two arm cuffs, one encircling the proximal half of the left arm and the other the middle part of the left forearm. Both blood flow velocity waveform and profile were shown to be markedly modified by changes in perfusion pressure and local peripheral vascular resistance. Reduction of perfusion pressure decreased both forward and reverse peak velocities, but had the largest effect upon reverse velocity. The upslope and the downslope of the forward velocity wave were left unchanged. Increase in local peripheral vascular resistance markedly augmented reverse peak velocity, whether perfusion pressure was normal or reduced. Increased resistance only slightly influenced peak forward velocity.

Arm↗
PubMed1984

[Diagnostic algorithms. Analysis of the factors conditioning their definition. An illustrative case (bilio-pancreatic pathology)].

A case of biliopancreatic pathology studied with traditional (the old algorithm) and the latest (new algorithm) diagnostic techniques is examined. A comparative analysis reveals the second to be simpler, less expensive and less dangerous to the patient. The hope is expressed that doctors will become better informed of the diagnostic criteria to employ for the purpose of cost reduction.

Biliary Tract Diseases↗
PubMed1981

The behavior of the Nicoladoni-Branham sign at rest and under effort.

The Nicoladoni-Branham sign may change because of exercise. Both dogs with femoral AVF and patients with lower-extremity AVF showed an increase in the Nicoladoni-Branham reaction after exercise as compared with its magnitude at rest. In both groups the AVFs were located near active muscles. We did not find this behavior in 3 patients with AVFs at points distant from the muscles used in exercise.

Animals↗
PubMed1979

[Effects of dopamine, noradrenaline and isoproterenol on pulmonary circulation in anesthetized dogs].

Experiments were performed on 19 anaesthetized open-chest dog instrumented with polyethylene catheters inserted: into the aorta, in pulmonary artery and in left atrium and with an electromagnetic flow-transducer placed around the ascending aorta in order to record : systemic arterial and pulmonary pressures, mean left auricular pressure and phasic aortic flow. Heart rate, stroke volume, total systemic and pulmonary resistance, cardiac work were moreover calculated. Each dog was given intravenously by slow infusione : Dopamine (micrograms 5--10--20/kg/min/ 5 min), Isoproterenol (microgram 0.125--0.25--0.5/kg/min/5 min) and Norepinephrine (microgram 0.25--0.5--1 /kg/min/5 min). Results obtained on systemic hemodynamics agree with those reported by many other investigators. On pulmonary circulation : Isoproterenol, at the tested doses, elicited vasodilator effects, Norepinephrine increased total pulmonary resistance but not pulmonary vascular resistance, while Dopamine did not modify or slightly reduced vascular pulmonary tone.

Animals↗
PubMed1979

A comparative study of poly(glycolic acid) and catgut as suture materials. Histomorphology and mechanical properties.

The "quality" of poly(glycolic acid) as an absorbable suture material was investigated in comparison with catgut. Tissue reactions to poly(glycolic acid) and plain catgut were examined histomorphologically at different time intervals after implantation in rats, and compared. Four mechanical properties were also examined as relevant quality factors: elastic stiffness, tensile strength, toughness, and percent elongation at rupture of the suture material per se (unknotted). The variation of these properties in poly(glycolic acid) implants was followed since their insertion in the tissues. Histological behavior and mechanical properties appear to be more closely correlated in the case of poly(glycolic acid) than in the case of catgut, as a consequence of a greater regularity of tissue reaction towards the synthetic material. Both tissue reaction and tensile properties variation are independent of size in the case of the braided poly(glycolic acid) sutures examined. Elastic stiffness and tensile strength decrease steadily in time; toughness and ultimate elongation display an increase up to a maximum within one day since implantation, and then decrease.

Abdominal Muscles↗