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Biomedical subjects

G Merico

Publications and source records attributed to G Merico.

13 recordsLinked to original sources
PubMed2006

Effect of L-thyroxine treatment on left ventricular function in subclinical hypothyroidism.

Aim of this study was to investigate the effects of thyroxine treatment on myocardial regional left ventricular (LV) systolic and diastolic function in patients with subclinical hypothyroidism (SH) by tissue Doppler imaging (TDI). Forty-two patients (29 women and 13 men; mean age 52.2+/-15.1 years) with SH, as judged by elevated serum thyroid-stimulating hormone (TSH) levels (>3.6 mIU/l; range, 3.8-12.0) and free thyroid hormones (FT4 and FT3) within the normal range, and 30 euthyroid volunteers (21 women and nine men; mean age 50.4+/-17.1 years) underwent standard echocardiography and TDI-derived early (Em) and late (Am) diastolic velocities, systolic (Sm) velocity, and isovolumetric relaxation time (IVRTm). Patients were randomly assigned to receive or not L-thyroxine replacement therapy. All patients returned after 6 months to repeat thyroid function tests and the evaluation of all parameters. No significant differences were seen in the Sm peak between SH and control groups. Respect to controls, SH patients exhibited a lower Em, a higher Am, and, subsequently, a reduced Em/Am ratio of both lateral wall (LW) and interventricular septum (IVS) (P<0.001 for both). The IVRTm was distinctly longer in SH patients, as compared to controls (P<0.001). At 6 months, L-thyroxine-treated patients showed a significant increase of Em (P<0.01) and a subsequent increase of the Em/Am ratio (P<0.01), whereas IVRTm significantly reduced (P<0.05). No significant change in any of these parameters was observed in the untreated group. Our data suggest that SH is associated with a subtle, reversible impairment of myocardial function. TDI analysis detects and extends these functional defects by displaying alterations in regional myocardial function. L-T4 replacement therapy should be advised for these patients with the aim to correct preclinical cardiac dysfunction and prevent the development of clinically significant myocardial dysfunction.

Echocardiography, Doppler↗
PubMed2006

Endothelial function in young subjects with vaso-vagal syncope.

BACKGROUND: The aim of this study was to determine whether endothelial function and inappropriate peripheral vasomotion have a significant role in the pathogenesis of neurally mediated syncope. METHODS: In 16 patients (mean age 28.2+/-5.8 years) with previous vaso-vagal syncope and in matched healthy subjects, endothelium-dependent flow-mediated dilation (FMD) and endothelium-independent response to glyceryl trinitrate (GTN), 25 mug, were measured in the brachial artery from high-resolution ultrasonography. Heart rate variability (HRV) analysis at rest and during tilt test was compared between two groups. RESULTS: In the subjects with positive tilt test, all HRV parameters were significant higher respect to subjects with negative tilt test (P<0.001). The patients with positive tilt test, showed persistent, marked variability of heart rate (HR), due to increased vagal activity with withdrawal sympathetic tone and consequently reduction of blood pressure (BP) (-30.4+/-4.2 mmHg, P<0.001) accompanied by a decrease in HR (-24.3+/-4.5 beats/min, P<0.001) compared to negative tilt test subjects. These findings prove the real presence of vagal hypertone in patients with syncope. In our study, HR reached values lower than 40 beats/min. FMD in patients with neurally mediated syncope were significantly greater than those in controls (respectively, 9.2+/-2.8% vs. 4.6+/-1.4%, P<0.01) whereas no differences were shown in the response to GTN (18.4+/-4.4% vs. 16.1+/-4.2%, n.s.). CONCLUSIONS: The augmented endothelial function and the abnormal vasodilation of peripheral arteries in association with bradycardia play an important role in the development of vaso-vagal syncope in young subjects.

Adult↗
PubMed1999

Microscopy in Camillo Golgi's times.

The research by Camillo Golgi in histology and pathology dates from 1865, the year in which he obtained his MD degree, to 1923, when his last scientific article was published. Beginning in the mid 1855s, microscope manufacturers in Europe started producing objectives based on the principle of immersion introduced in 1847 by Giovan Battista Amici. The immersion objectives greatly improved the resolution of microscopic observations at high magnifications. From 1860 to 1872, technological improvements in microscope optics and the practicality of their use provided a larger community of investigators effective tools needed to study the structure of the nervous system. This progress in microscopy was associated with the application of new histological techniques, mastered by the chromoargentic reaction introduced by Golgi in 1873. In 1872, further progress in microscopy stemmed from the application of notions of applied physics to the production of microscope optics. These developments in microscopy will be briefly reviewed here.

Histology↗
PubMed1987

[Colonic hemorrhage caused by vascular dysplasia. Surgical treatment].

On the basis of their own clinical experience and the data provided in the literature, the authors examine the question of the surgical therapy of the two main dysplastic diseases of the colon, i.e. colonic angiodysplasia and angiomatosis. While the larger cavernous angiomas necessarily call for surgery, large-bowel angiodysplasia and capillary angiomas, which are disease falling primarily within the internist's sphere of competence, may be treated conservatively, when symptomatic, by endoscopic electrocoagulation, though a surgical approach may be contemplated in that small percentage of cases presenting coagulopathy or frequent, intense haemorrhages with a severe anaemic tendency.

Colon↗
PubMed1987

[Our experience in the surgical treatment of diverticular disease (I: Election)].

The authors review their patient population with regard to the surgical treatment of diverticular disease. This population consists of 76 cases, 30 of which were subjected to elective surgery. They conclude by stating that, in the light of their experience, the most effective elective operation is resection of the tract affected by diverticuli followed by and end-to-end anastomosis with the protection of a decompressive transversostomy.

Acute Disease↗
PubMed1987

[Synchronous abdomino-perineal amputation (global evaluation of the intervention in our experience)].

In the light of their experience, the Authors examine the validity of synchronous abdomino-perineal resection. Their study population consists of 224 such operations. On the basis of the results achieved, the conclusion is reached that there is still no realistic alternative today to synchronous abdomino-perineal resection for the treatment of malignancies whose lower borders lie at a distance of less than 6.5 cm from the anal margin.

Female↗
PubMedDate not supplied

[Anastomotic complications in the surgical treatment of rectal neoplasms].

The authors review the problems relating to the healing of colorectal anastomotic complications following anterior resection. They report on their own experience with 328 anastomoses, 281 of which constructed manually and 47 using a mechanical suturing gun. Following manual anastomosis, the reported incidence of clinical dehiscence was 1%, as against a 10.3% incidence of radiologically detectable dehiscence. In the cases of mechanically produced anastomoses the incidence of clinical dehiscence was 6.4%. In 2 cases stenosis developed as a result of the clinically manifest dehiscence following manual anastomosis. In the patients undergoing mechanical anastomosis, occlusion occurred in one case and stenosis in another, without any concomitant peri-anastomotic inflammatory processes; these complications were caused by a membrane extending between the margins of the anastomosis. The authors ascribe the greater incidence of clinically important dehiscence following mechanical anastomosis to a greater sensitivity of the mechanical suture to colonic contamination compared to the manual suture. According to the authors, the stenosis is attributable to inflammatory processes resulting from the dehiscence in the manual anastomosis cases and from the anastomotic structure in the mechanical-suture case.

Anastomosis, Surgical↗
PubMedDate not supplied

[Biomechanical-clinical interpretation of firearm wounds. General problems. X. Propedeutic ABC of terminal ballistics].

Any discussion of firearms which failed to take due account of the complex interaction between the weapon and its user would be missing the point. This interaction takes on a major role, particularly in the case of military ordinance weapons; their "optimal" use demands the maximum control of this interaction, which is of the utmost importance for the tactical role of the soldier-weapon system. The use of the latest long-barrelled ordinance firearms is more acceptable precisely because of their smaller calibre (which also means reduced interaction with the user). Today the traditional primacy of the long-barrelled weapon (now getting progressively shorter) is threatened by the short-barrelled gun cartridge, which we have seen used on an extensively scale in recent militia warfare. Paradoxically, it is precisely this cartridge, whose main shortcoming is its low propellant content (and thus reduced kinetic energy) which is expected to provide the kind of killing performance capable of snuffing out even "the dead man's last five seconds".

Biomechanical Phenomena↗
PubMedDate not supplied

[Biomechanical-clinical interpretation of firearm wounds. General problems. XI. Propedeutic ABC of terminal ballistics].

The pathogenetic potentiality of firearms differs in relation to whether we are dealing with rifled long-barrelled weapons, handguns, or smooth-bore long-barrelled guns. Up until a few years ago, the tissue-damaging effect, at least in the modern warfare context, of short-barrelled or smooth-bore long-barrelled firearms, was thoroughly negligible; today, however, their impact, as causes of wounds and death, is steadily increasing, and for the first time small bullets designed for low-cost military training are also coming to play a primary role on the battlefield. At the same time short-gun bullets are appearing which, which in the name of "stopping power" seem to contradict the very definition of a handgun. The smooth-bore long-barrelled gun, in turn, is casting off the anti-humanitarian image of the trench gun to play the more suggestive ordinance role of the grenadiercumhunter.

Biomechanical Phenomena↗
PubMedDate not supplied

[Terminal ballistics. 1].

We have chosen to conceive of terminal ballistics as a violent and extremely rapid confrontation between two forms of resistance before the final state of rest is reached. This definition, which cannot help but don the admittedly loud and outlandish garb of physics, is the most promising for the purposes of biological interpretation. The main characters on this stage are two, but only one of these really plays the lead, namely the human target, which acts out the basic roles inherent in its physical make-up; the other, the bullet, remains a background figure, frozen in its walk-on part, and ready for the next performance. This modus operandi, which is no simplification, but rather an academic necessity, enables us to focus on images which stand out more clearly as a result of an intensive macroscopic spotlight which brings out the features of the individual phenomena, broken down into a succession of close-ups, and subtracts them from the cold physical nature of this or that form of inert matter, which here is merely an occasional, disagreeable witness, or even more, a standing from time to time for but one of the infinite facets of the biological composite being. Here, then, faced with a kind of exploded macrophotograph of a complex kaleidoscope, we see the animal universe, of which we capture so far the plasticity, the subdivisibility, the anisotropy and the cavitation.

Animals↗
PubMedDate not supplied

[Terminal ballistics. 3].

This brief chapter, focusing essentially on a single topic, has been written in homage to Emile Theodor Kocker, a masterful exponent of the art of surgery and founder of the culture of terminal ballistics. For most of the literature we are indebted to Fackler and Dougherty, who, with the particular grasp, and fair of historians, act as guides on a trial which is only apparently retrograde, but which actually bears eloquent witness to the fact that even in the most physically tangible of arts, namely the art of surgery, inspired curiosity may help us to go well beyond the limits of our day and age. This chapter is also dedicated to the memory of another great surgeon, Vittorio Pettinari, who for one of the authors was an incomparable mentor and past-master of such curiosity.

Animals↗