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Biomedical subjects

L Marchini

Publications and source records attributed to L Marchini.

16 recordsLinked to original sources
PubMed2001

Case reports: evolution of prosthetic rehabilitation for a patient with severe loss of periodontal support.

This paper describes the development of a technique to make a fixed bridge for a patient with severe reduction of periodontal support. Initially, the bridge was temporarily cemented over copings. However, when the super-structure was periodically removed for inspection, the copings were easily dislodged, with a risk of fracture of the abutment teeth. Consequently, the technique was modified by using lateral screws to fix the bridge to the copings. This design allows easy periodical removal, cleaning, repair and inspection of the abutment teeth.

Cementation↗
PubMed1999

Diagnostic strategies in venous thromboembolism.

BACKGROUND AND OBJECTIVE: Diagnosis of acute deep vein thrombosis (DVT) and of pulmonary embolism (PE) is often difficult: symptomatic patients are usually investigated employing several diagnostic tests, which should be appropriately selected and sequenced, taking into account their sensitivity, specificity, safety and cost. The objective of this paper is to evaluate the performance of the new diagnostic tests and their combination in rational diagnostic strategies. DESIGN AND METHODS: A literature review was made using a Medline(R) database search for the period 1988-1998 on the following key words in various combinations: diagnosis, diagnostic strategy, venous thrombosis, pulmonary embolism, venous thromboembolism. Results of a new study by our group on diagnosis of DVT in hospitalized patients are also discussed. RESULTS: In patients with symptoms or signs suggestive of DVT, compression ultrasound (CUS) appears to be the diagnostic test of first choice, since it is a noninvasive test with high specificity and sensitivity for proximal DVT (about 97%). When CUS gives a negative result it is usually recommended that the test is repeated after one week, since its sensitivity for calf DVT is poor. The positive and negative predictive values (PPV and NPV) of CUS in symptomatic outpatients can be improved if adequate consideration is given to clinical diagnosis, using a standardized model (ref. #9), which allows symptomatic outpatients to be categorized as having a high, moderate or low probability of DVT. In case of agreement between clinical diagnosis and CUS results, no further testing is needed: patients with high or intermediate clinical probability and positive CUS results are treated, while in patients with low clinical probability and negative CUS results the diagnosis of DVT is excluded. In the case of discrepancy between clinical diagnosis and CUS results, D-dimer test and/or venography are requested. However in patients who develop signs or symptoms of DVT in the hospital the clinical model does not work, and diagnosis should be based on an appropriate mix of CUS, D-dimer (DD) test and venography. In patients presenting with signs or symptoms of pulmonary embolism, the ventilation/perfusion (V/P) lung scan remains a pivotal diagnostic test, and pulmonary angiography the reference standard, but both methods have limitations and in recent years other diagnostic tests such as echocardiography, helical (or spiral) computerized tomography, and magnetic resonance imaging have been introduced into clinical practice. Moreover, all four diagnostic tools mentioned for DVT diagnosis can be considered. Several diagnostic strategies have been proposed and evaluated in comparative studies but there is still debate over the most efficient test combination or sequence. INTERPRETATION AND CONCLUSIONS: Diagnostic strategies which include adequate consideration of clinical diagnosis using standardized models have the potential of being more efficient for outpatients (but not for inpatients) with symptoms or signs suggesting DVT of lower limbs. For patients with suspected PE, several diagnostic strategies have been assessed: V/P lung scan remains a pivotal diagnostic test, but its limitations have been increasingly recognized and newer non-invasive techniques are gaining credit. A consensus is still to be reached over the most appropriate combination of diagnostic tests.

Angiography↗
PubMed1997

Evaluation of circulating galanin levels after exercise-induced pituitary hormone secretion in man.

The neuropeptide galanin (GAL) is widely distributed in the central and peripheral nervous systems, anterior pituitary, and adrenal medulla. GAL is colocalized with corticotropin (ACTH) in the human pituitary and with epinephrine (E) and norepinephrine (NE) in chromaffin cells of the adrenal medulla. The function of GAL in peripheral tissues is not known, although the presence of the peptide in corticotrophs and the adrenal gland suggest that it participates in stress responses. In the present study, we investigated whether GAL is cosecreted with ACTH during activation of corticotrophs by an acute physical exercise test. Circulating levels of GAL and pituitary hormones were measured in healthy exercise-tested and control male subjects. Blood samples were collected during basal conditions, maximal power output (MPO), and the recovery period. Control subjects were sampled during the resting condition. The pituitary response to exercise was characterized by a significant increase in ACTH plasma levels (peak value 13.28 +/- 2.19 v 6.68 +/- 1.01 pmol/L, P < .05) and growth hormone (GH) serum levels (peak value, 14.53 +/- 5.59 v 0.29 +/- 0.1 microg/L, P < .02), with the peak in hormone levels detected 15 minutes after the end of exercise. No change in circulating prolactin (PRL) levels was detected. An expected significant increase in plasma levels of both E (peak value, 1,574.41 +/- 403.31 v 267.44 +/- 60.03 pmol/L, P < .01) and NE (peak value, 7,275.25 +/- 955.80 v 961.51 +/- 168.40 pmol/L, P < .01) was also observed. Plasma GAL levels were not affected by the acute exercise test, with the levels being comparable to baseline during the exercise test and the recovery phase. At any sample time, GAL values were comparable between exercise-tested and control subjects. These data show that despite the colocalization of GAL and ACTH within the same pituitary cells, the two peptides are not coreleased in response to stress resulting from acute physical exercise. Furthermore, pituitary GAL seems not to be involved in the stimulation of GH secretion in exercise-tested subjects. The results also indicate that GAL is not coreleased with E or NE in response to the exercise-induced stress condition.

Adrenocorticotropic Hormone↗
PubMed1995

Lipoprotein Lp(a) and cerebrovascular disease in the elderly: correlations with the severity of extracranial carotid atherosclerosis assessed by ultrasonography.

High levels of lipoprotein Lp(a) are related to cerebrovascular disease clinical manifestations, as well as to the severity of extracranial carotid atherosclerosis assessed by ultrasonography. In order to investigate the relationship of Lp(a) to the severity of carotid atherosclerosis in the elderly, 100 subjects, aged 78.5 +/- 0.6 yrs underwent an echo-color-doppler scanning of carotids; atherosclerosis severity, assessed as maximum percentage stenosis, presence of complicated plaque and Intima-Media Thickness (IMT), was related to Lp(a) levels, assayed by an immunoenzymatic procedure. A slight association between Lp(a) and CVD clinical manifestations was apparent only in subjects under 78 yrs and for Lp(a) values above 25 mg/dL. Lp(a) levels were not related either to the degree of stenosis, the presence of complicated plaque, or IMT. As for other selected risk factors, while no relationship was found for clinical CVD and IMT, the maximum percentage of stenosis and the presence of complicated plaques were positively related to LDL-cholesterol in subjects under 78 yrs. We can conclude that Lp(a), albeit unrelated to the severity of extracranial vessel atherosclerosis, maintains a role as cerebrovascular risk factor in the elderly, being slightly related to clinical manifestations; however its discriminant power is lower than in middle-aged people and further decreases throughout ageing.

Aged↗
PubMed1991

Effects of cytidine 5'-diphosphocholine administration on basal and growth hormone-releasing hormone-induced growth hormone secretion in elderly subjects.

The basal and GH-releasing hormone-stimulated secretion of GH declines in the elderly. We tested the ability of cytidine 5'-diphosphocholine, a drug used in the treatment of stroke and Parkinson's disease, to alter GH secretion in 11 healthy elderly volunteers, aged 69-84. Each subject received an iv infusion of 2 g of cytidine 5'-diphosphocholine or normal saline. GHRH and TRH were also administered during cytidine 5'-diphosphocholine infusions. The infusion of cytidine 5'-diphosphocholine induced a 4-fold (p less than 0.05) increase in serum GH levels over basal values. A small increase in GH was seen after GHRH administration. However, the addition of GHRH to the cytidine 5'-diphosphocholine infusion resulted in a GH response which was significantly greater than that seen after GHRH alone; the integrated concentration of GH was more than 2-fold greater in the cytidine 5'-diphosphocholine treated group (706.85 +/- 185.1 vs 248.9 +/- 61.4 micrograms.l-1.(120 min)-1; p = 0.01). The PRL and TSH responses to TRH were not significantly affected by cytidine 5'-diphosphocholine infusion, indicating that dopaminergic mechanisms are not involved. These studies demonstrate that cytidine 5'-diphosphocholine can enhance basal and GHRH-stimulated GH release in the elderly, but the mechanism of action of the drug remains unclear.

Aged↗
PubMed1985

[Effect of blood levels of carboxyhemoglobin (COHb) on erythrocyte filtration time in young smokers].

The effects of chronic exposure to carbon monoxide on some rheologic parameters (erythrocyte filtration time in particular) and on FEV1, and on FEF25-50 were studied in young smokers. A positive correlation among number of cigarettes day, COHb blood levels and erythrocyte filtration time was found. Packed red cell volume, fibrinogen concentration and platelet count were unaffected; no evidence of small-airway obstruction was observed. The alteration of erythrocyte deformability may be an early sign of hemorheological impairment which can progressively worse if high COHb blood levels are chronically maintained, with damaging effects on vessel function.

Adult↗
PubMed1985

[The hormonal response to hypercalcemic stimulation: the difference between male and female young people].

The aim of our study was to evaluate the pattern of response of thyroid Calcitonin (CT) secretory cells in young healthy people after specific stimulation. For this purpose, test of 60'' i.v. calcium infusion in a dose of 4 mg/Kg lean body mass was employed. Blood samples were taken at times-5', 0', 2', 5', 10', 15', and 30' after the infusion, to determine total Calcium (Ca), ionized calcium (Ca++) and CT concentrations. As a result, plasma CT increased significantly (f = 24.51, p less than 0.000001) in both sexes, while males showed stimulated CT values about double than the female ones: the difference was statistically significant throughout the test. In males too, we observed a strong and significant (r = 0.92, p less than 0.01) correlation between ionized calcium increases and CT responses. This correlation was found neither in males as regards total calcium, nor in females. In conclusion, our data confirm the higher CT secretion in males, indicating also a more constant pattern of response in this sex. Eventually, ionized calcium proves to be the real effective provocative stimulus for CT secretion.

Adult↗
PubMed1975

[On the hypouricemic action of an alkaline mineral water in the aged].

The importance of loading tests, particularly venous loading with fructose, in the determination of changes in purine metabolism is stressed. Such changes may well be present even if basic uricaemia is within the limits of normal. Fructose loading was used to determine the hypouricaemising and uricosuric effects of a mediomineral water in aged subjects following daily administration. A hypouricaemising effect was noted and there was an improvement in loading curve patterns. This effect is considered to be primarily due to the uricosuric activity of the water itself. Sugar tolerance and the insulin response to loading, on the other hand, were not altered by the treatment.

Aged↗