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Biomedical subjects

P Carletti

Publications and source records attributed to P Carletti.

At least 19 recordsLinked to original sources
PubMed2006

Chemical and biological characterization of dissolved organic matter from silver fir and beech forest soils.

Despite a growing attention to the dissolved organic matter (DOM) in terrestrial ecosystems and evidence of the fact that vegetation affects the quality of both undissolved and dissolved organic matter in soil, the role of DOM as a biological indicator is still poorly understood. In this work, the fertility of 59 sites, divided into eight key alliances of the order Fagetalia sylvaticae Pawl., was studied considering chemical and biological parameters such as soil DOM, hormone-like activity, low-molecular-weight (LMW) aliphatic and phenolic acids, and floristic data. Both non-parametric tests and principal component analysis (PCA) revealed differences between silver fir and beech forests and within each type of forest. There were also differences between neutrophilous and acidophilous types. What's more, PCA reveals the dominance of the auxin (IAA)-like activity, and of some phenolic acids in distinguishing the acidophilous beeches (ACI) form the other types, whereas the gibberellin (GA)-like activity is more relevant in neutrophilous conditions such as thermophilous (THE) and mesophilous (MESO) beeches and montane (MO), high montane (HMA), high montane (HMC) silver fir forests. The GA-like activity is also related to the succinic, fumaric, malonic, and l-malic acids in the MO, HMA and HMC silver fir forests. Moreover, the role of LMW aliphatic acids in mobilizing the hormone-like activity, which improves forest growth, is stressed. The growth of seedlings of Picea abies was influenced by the phenolic acid content. At concentrations between 1 and 100 microM, phenylacetic and protocatechuic acids inhibited root growth to the same extent as indoleacetic acid, while p-hydroxybenzoic acid had a stimulating effect comparable to that of gibberellic acid. The aliphatic and phenolic acids appear to be related to plant strategies that influence soil fertility affecting plant growth through rhizodeposition. The role of LMW aliphatic and phenolic acids as molecular markers of ecosystem function is noted.

Abies↗
PubMed1995

[Echo-Doppler in chronic kidney transplant rejection. The diagnostic prospects using indices of the ascending systolic phase].

To date, Doppler US has been rarely used to diagnose chronic renal transplant rejection because of its low sensitivity. Nevertheless, all the results have been obtained from the analysis of flow-metric indices, mainly considering the diastolic phase of the Doppler waveform, e.g., the resistance index (RI) and the pulsatility index (PI). This study was aimed at investigating if Doppler diagnostic accuracy in renal transplant monitoring can be increased by studying the systolic phase, considering peak arterial systolic velocity (Vp), acceleration time (AT) and acceleration index (AI). Seventy-six renal transplant recipients were examined with color-Doppler and duplex Doppler US, which showed 47 well-functioning and 29 hypofunctioning kidneys. The diagnosis was confirmed with perfusion scintigraphy with 99mTc DTPA, biopsy and 6-month clinical-laboratory follow-up. The means of Vp, AI, AT and RI relative to the group of patients with normal renal function were compared with those in the group of patients with chronic rejection. Critical values were measured at the segmental arteries (Vp = 70 cm/s, AI = 7 m/s2, AT = 100 ms), at the interlobar arteries (Vp = 45 cm/s, AI = 4 m/s2, AT = 100 ms) and at the arcuate arteries (Vp = 35 cm/s, AI = 3 m/s2, AT = 100 ms). On the basis of these values, normal functioning transplants were differentiated from hypofunctioning ones. RIs were altered (> 0.75) in 8 of 17 chronic rejections and in 3 of 47 normal transplants, with 47.1% sensitivity and 93.6% specificity. The combination of RI with Vp and AI strongly increased both sensitivity (100%) and specificity (82.98%). Combined AI and RI exhibited 94.1% sensitivity and 89.3% specificity. In conclusion, the indices of the ascending systolic phase, in peripheral vascular samplings, are clearly more efficacious than RI alone and index combination exhibits the highest diagnostic accuracy.

Adult↗
PubMed1995

Leaching and corrosion of polyvinyl chloride (PVC) tubes in a dialysis water distribution system.

PVC tubes, from the dialysis water distribution system of a 14 and a 7 year old plant, were analysed by scanner electron microscopy (SEM) and X-ray microanalysis (EDAX). Results showed that the leaching of material occurs depending on time of use. The phenomenon does not modify the chemical composition of the material. Results suggest that PVC alterations, induced by time, could support bacterial proliferation thus reducing the quality of dialysate.

Corrosion↗
PubMed1994

Behavior of beta 2-microglobulin (B2-m) serum levels in uremic patients.

This study was performed in 97 hemodialysis patients (85 on HD and 12 on CAPD) to investigate the possible correlation between B2-m and hemodialysis-related amyloidosis syndromes (HRA-S); differences in B2-m and HRA behavior between patients hemodialysed with cellulose and synthetic membranes were also included in the present study. Data indicate that B2-m levels are not correlated with dialysis length or with the type of membrane used for the dialysis. On the contrary, in 16 patients with the Carpal Tunnel Syndrome, a significant correlation was found between the CTS, the dialysis length and the type of membrane (greater incidence with cellulosic membranes).

Adult↗
PubMed1993

Does anemia correction by rHuEPO improve uremic cardiopathy?

The correction of renal anemia by recombinant human erythropoietin (rHuEPO) makes it possible to assess the effect of anemia on uremic cardiopathy (UC). So far, conflicting results have been reported. We studied 10 hemodialyzed patients aged (51 +/- 18 years, dialytic age 47 +/- 18 months) before and after rHuEPO treatment. All patients underwent an echocardiogram before, and six months after stable hematocrit (31 +/- 2) was obtained. The results show a reduction in LVDD. No improvement in ejection fraction and in ventricular hypertrophy was observed, probably owing to an increase in blood pressure. Finally, there is a possibility that the myocardium of hemodialyzed patients undergoes anatomical changes which may not improve, even after anemia correction.

Adult↗
PubMed1992

HBV infection in hemodialysis patients: monitoring and prevention.

From 1986 to 91, 174 dialysis patients were studied. The prevalence of previous HBV infection and of chronic carriers was 33.3 and 4.6%, respectively. Immunization rate after vaccination (3 doses) was 63%. In 1991, we proposed a vaccination with 4 doses and recommend a 6-monthly anti-HBs evaluation to assess the timing of any booster dose needed.

Aged↗
PubMed1992

Epidemiology of viral hepatitis in dialysis centers: a national survey.

Because of the great problem of viral hepatitis in hemodialysis patients, the Italian Society of Nephrology decided to perform a national epidemiologic survey. We contacted 467 nephrological centers by a questionnaire which let us have information on 25,746 uremic patients: 18,338 on HD, 2,250 on PD and 5,176 with kidney transplant, respectively 78.5% of the total Italian dialysed patients and 91.4% of the total transplanted patients. Statistical analyses were performed. HBV infections occur in 7.8% of the patients (2,008 cases) but considering that 485 cases became spontaneously negative, the true overall incidence of chronic carriers falls to 4.9%. The main causes of the infection are reported as transfusions (64.3%) and dialysis environment (12%). The vaccination program performed by 93.2% of the centers, obtained an efficacious seroconversion in 4,626 of 7,790 cases vaccinated: the vaccine currently most utilized is the recombinant type administered by means of 3 versus 4 boosters. In the 2nd part of the survey, we report information concerning the presence of nephropaties associated with HBV infections in nonuremic patients (208 cases). We present and discuss the clinical picture of the nephropaties, the hystologic bioptic pattern and the prognosis of the kidney pathology.

Carrier State↗
PubMed1992

Risk factors and clinical expression of HCV infection in hemodialysis patients.

In our Dialytic Unit, the prevalence of antibodies to HCV (anti-HCV) was 16.4% in 1990 (73 hemodialyzed) and 21% in 1991 (105 hemodialyzed). The incidence of seroconversion was 13.1%. The transaminase behavior was similar in a group of anti-HCV-positive and a group of anti-HCV-negative patients and with previous HBV infection. Blood transfusions and dialytic age did not affect anti-HCV positivity.

Adult↗
PubMed1990

LY 171555-induced catalepsy and defensive behavior in four strains of mice suggest the involvement of different D2 dopamine receptor systems.

The D2 dopamine receptor agonist LY 171555 (0.5 to 5 mg/kg) induces dose-dependent catalepsy in C57BL/6, DBA/2 and BALB/c inbred strains of mice. This effect shows marked strain-dependent differences, since the response of C57BL/6 is significantly lower than those presented by the other two inbred strains at all doses tested. In previous studies we have shown that the D2 agonist at doses ranging from 0.5 to 5 mg/kg induces hyperdefensive responses toward nonaggressive opponents in mice of the C57BL/6 and BALB/c but not of the DBA/2 strain. Here we report that the outbred CD1 mice present both cataleptic and hyperdefensive responses when challenged with LY 171555. Forty-five percent of individuals presenting high defensive response and 11% high cataleptic scores. No correlation was found between catalepsy and hyperdefensiveness in CD1 mice following administration of 1 mg/kg of the D2 agonist. These results suggest that D2 receptor stimulation results in different behavioral responses, possibly mediated by different dopaminergic systems, depending on the genetic make up.

Animals↗
PubMed1985

[Growth hormone after baclofen in normal and acromegalic subjects].

Serum growth hormone (GH) levels in basal conditions (two samples) and 30, 60, 90, 120, 150 and 180 minutes after oral administration of baclofen (20 mg) were evaluated in 6 healthy subjects and in 6 acromegalic patients. The effect of cimetidine (400 mg i.v.) administrated 45 minutes after baclofen (20 mg by mouth) were evaluated in 9 healthy women. Baclofen was able to significantly rise serum GH levels in normal subjects but no in acromegalic patients. Cimetidine suppress GH increase induced by baclofen. It was concluded that: 1) baclofen, GABAb receptor agonist, stimulate GH secretion by inhibition of GIF secretion or by stimulation of GRF secretion; 2) istamine, through H2 receptors in the hypothalamus, is important to mediate GH release induced by stimulation of GABAb receptors.

Acromegaly↗
PubMed1985

[Prolactin after baclofen in healthy subjects and prolactinoma patients].

Serum prolactin (PRL) levels in basal conditions (two samples) and 30, 60, 90, 120, 150 e 180 minutes after oral administration of baclofen (20 mg) were evaluated in 6 healthy subjects and in 10 patients with prolactinoma. The effect of baclofen (20 mg by mouth) on the PRL secretion cimetidine (400 mg i.v.) or domperidone (20 mg i.v.) induced were evaluated in 9 healthy women by administration of baclofen 60 minutes before cimetidine or domperidone. Baclofen was unable to significantly rise serum PRL levels in healthy subjects and in patients affected by prolactinoma and furthermore did not interfere with PRL rise domperidone induced. On the contrary baclofen decreased PRL rise cimetidine induced. It was concluded that: in basal condition, GABAb receptor don't play an obvious role in modulation of PRL secretion; when H2 istaminergic inhibition on PRL secretion is blocked (at an hypothalamic site), a GABA inhibition, b receptor mediated, on PRL secretion became more clear; the domperidone blockade of hypophysial dopaminergic receptors suggests that GABAb modulation of prolactin secretion don't obtain itself by dopaminergic pathways.

Adult↗
PubMed1984

[Neurohypophyseal diabetes insipidus. Anatomo-clinical correlations].

Eighteen patients aged between 14 and 60 years suffering from diabetes insipidus were studied. Diabetes insipidus was diagnosed by means of Robertson's test. All patients underwent C.T. scanning and evaluation of PRL basally and after TRH (200 mcg e.v.). Twelve patients (66%) showed neurological lesions (secondary central diabetes insipidus). Six of these patients had hyperprolactinaemia. Our data suggest that most of central diabetes insipidus are associated with central system nervous (S.N.C.) damage. In same cases the presence of hyperprolactinaemia suggests a brain damage. Therefore neuroradiological study is very important in all cases of neurohypophyseal diabetes insipidus.

Adolescent↗
PubMed1984

[Evaluation of TSH secretion after GnRh in patients with primary hypothyroidism].

6 women (mean age 38 years) with high Thyroid Stimulating Hormone (TSH) serum levels because affected from primary hypothyroidism were studied. 6 healthy women (mean age 31 years) represented the control group. All subjects underwent evaluation of serum TSH, Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH), basally and 20, 30, 60, 120 minutes after administration of Gonadotropin Releasing Hormone (GnRH: 100 meg. IV). Seric FSH and LH show a large increase 30 minutes after GnRH either in healthy or in hypothyroid subjects. TSH is unresponsive to GnRH in normal condition, while shows a clear decrease (-78%) 30 minutes after GnRH in primary hypothyroidism. Rarely the hypothalamic releasing hormones possess an inhibitory effect on anteipophyseal secretions. Previously a GnRH inhibitory effect on prolactin (PRL) release from PRL secreting tumors in rat. The GnRH inhibitory effect on TSH release in pathological conditions such as primary hypothyroidism is difficult to explain: it may be that GnRH acts on Central Nervous System or at pituitary level: in the last case it could bind sites which are not quite different in the different glycoprotein secreting cells.

Adult↗
PubMed1981

[GH after baclofen and diazepam].

It has been proposed that GABAergic receptors possess two functionally distinct, but strictly co-operating binding sites, one for GABA itself, another for benzodiazepines. The activation of GABA receptor is followed by opening of the Cl- channels. This action is strengthened if both binding sites of GABA receptor are contemporaneously engaged by their respective agonists. Baclofen, a GABAergic drug, is able, in acute administration, to determine an increase of serum GH in man. The aim of this work was to control if benzodiazepines can strengthen this metabolic effect of Baclofen in vivo. Five healthy voluntary women were studied. Blood samples for serum GH evaluation were collected basally and 30, 60, 90, 120, 150, 180, 210 minutes after oral administration of 20 mg. of Baclofen. This test was repeated one week after oral administration of 12 mg. die of Diazepam. The results were analyzed for paired data. The finding show that the metabolic effect of Baclofen on GH secretion are prolonged in time after Diazepam premedication and suggest that GABA-benzodiazepines interaction is effective at hypothalamo-hypophyseal level in man.

Baclofen↗