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Biomedical subjects

A Rosati

Publications and source records attributed to A Rosati.

At least 19 recordsLinked to original sources
PubMed2006

Physiological effects of kaolin applications in well-irrigated and water-stressed walnut and almond trees.

BACKGROUND AND AIMS: Kaolin applications have been used to mitigate the negative effects of water and heat stress on plant physiology and productivity with variable results, ranging from increased to decreased yields and photosynthetic rates. The mechanisms of action of kaolin applications are not clear: although the increased albedo reduces leaf temperature and the consequent heat stress, it also reduces the light available for photosynthesis, possibly offsetting benefits of lower temperature. The objective of this study was to investigate which of these effects are prevalent and under which conditions. METHODS: A 6% kaolin suspension was applied on well-irrigated and water-stressed walnut (Juglans regia) and almond (Prunus dulcis) trees. Water status (i.e. stem water potential, psi(s)), gas exchange (i.e. light-saturated CO2 assimilation rate, Amax; stomatal conductance, g(s)), leaf temperature (T(l)) and physiological relationships in treated and control trees were then measured and compared. KEY RESULTS: In both species, kaolin did not affect the daily course of psi(s) whereas it reduced Amax by 1-4 micromol CO2 m(-2) s(-1) throughout the day in all combinations of species and irrigation treatments. Kaolin did not reduce g(s) in any situation. Consequently, intercellular CO2 concentration (C(i)) was always greater in treated trees than in controls, suggesting that the reduction of Amax with kaolin was not due to stomatal limitations. Kaolin reduced leaf temperature (T(l)) by about 1-3 degrees C and leaf-to-air vapour pressure difference (VPD(l)) by about 0.1-0.7 kPa. Amax was lower at all values of g(s), T(l) and VPD(l) in kaolin-treated trees. Kaolin affected the photosynthetic response to the photosynthetically active radiation (PAR) in almond leaves: kaolin-coated leaves had similar dark respiration rates and light-saturated photosynthesis, but a higher light compensation point and lower apparent quantum yield, while the photosynthetic light-response curve saturated at higher PAR. When these parameters were used to model the photosynthetic response curve to PAR, it was estimated that the kaolin film allowed 63% of the incident PAR to reach the leaf. CONCLUSIONS: The main effect of kaolin application was the reduction, albeit minor, of photosynthesis, which appeared to be related to the shading of the leaves. The reduction in T(l) and VPD(l) with kaolin did not suffice to mitigate the adverse effects of heat and water stress on Amax.

Carbon Dioxide↗
PubMed2006

Chronic kidney disease is still present after renal transplantation with excellent function.

According to a k/DOQI work group, chronic kidney disease (CKD) can be present also in subjects with glomerular filtration rate (GFR) >90 mL/min or a serum creatinine (sCr) below 1.3 mg/dL. The aim of this study was to document the prevalence of clinical or biologic abnormalities among 190 cadaveric renal transplant patients with excellent and stable renal function at 6 months after transplantation as well as 5 years later. The recipients were 82 women and 108 men of mean age at transplantation of 44.56 +/- 11.73 years. All patients were on Neoral-based immunosuppression with at least 5-year follow-up. Mean sCr was 1.18 +/- 0.2 mg/dL. Mean GFR was 78.57 +/- 27.06 mL/min. Systolic blood pressure was >130 mm Hg in 56.6%, although 78.3% of patients were on antihypertensive therapy; 34.3% were anemic; 75.4% had serum cholesterol >200 mg/dL; 62.2% had serum triglyceride levels >170 mg/dL. Serum intact parathyroid hormone >100 pg/mL was observed in 38% of patients and 43% were on vitamin D supplementation, and 11.4% had developed posttransplant diabetes mellitus. With respect to controls, von Willebrand factor was higher in 81.2% (P < .0001; RR = 11); serum homocysteine levels in 75% (P < 0.001; RR = 7.61); PAI-1 in 37.5% (P = .0009; RR = 4). At 5 years posttransplantation we observed an overall improvement in these abnormalities. The vast majority of renal transplant patients with excellent graft function belong to stage 1 of CKD being affected by hypertension, dyslipidemia, anemia, and residual hyperparathyroidism. Markers of endothelial dysfunction were largely abnormal, a condition that could predispose to cardiovascular events.

Adult↗
PubMed2006

Low 1-year cyclosporine microemulsion doses are associated with better 5-year renal graft function: an insight from MOST, a multinational observational study.

BACKGROUND: In earlier registry analyses, cyclosporine at doses of < 3 mg/kg/d at 1 year post-renal transplantation has been associated with significant graft loss or reduction in renal function. Improvements in cyclosporine formulation with increased bioavailability, plus the use of more efficient comedications, may now confer better outcomes. To determine the effect of the 1-year cyclosporine microemulsion (CsA-ME) dose on renal allograft function at 5 years, we analyzed data collected from 2889 patients with documented graft survival to year 5 in a prospective, multinational, observational study-Neoral MOST. RESULTS: Glomerular filtration rate (GFR) at year 1 was 63 +/- 20 mL/min and 59 +/- 22 mL/min at year 5. The multivariate analysis including year 1 CsA-ME dose as factor and GFR at 1 year as covariate revealed the most significant factors affecting GFR at year 5 were 1-year GFR, donor age > 60 years, and CsA-ME dose at 1 year. Risk factors associated with reduction in 5-year GFR (<65 mL/min) included donor or recipient age >60 years, delayed graft function, cadaveric donor, previous graft, and acute rejection. CsA-ME dose <3 mg/kg/d was found to protect GFR. Analysis of GFR at each year posttransplantation (Wilcoxon model) found 1-year CsA-ME (cutoff 3 mg/kg/d) had a significant effect at each time point. CONCLUSIONS: Compared to higher doses, CsA-ME <3 mg/kg/d at year 1 posttransplantation is associated with increased preservation of renal allograft function at year 5.

Aged↗
PubMed2005

Efficacy and safety of Palmaz stent implantation in the treatment of renal artery stenosis in renal transplantation.

To verify the long-term efficacy and safety of Palmaz stent implantation in the treatment of transplant renal artery stenosis (TRAS), we reviewed the charts of 26 patients affected by TRAS and treated by percutaneous transluminal angioplasty (PTA) followed by permanent insertion of a Palmaz stent. The mean follow-up period was 43.31 +/- 33.6 months. The mean blood pressure fell significantly at 1 month after stenting (118 +/- 8.1 vs 101 +/- 7.8 mmHg; P < .0001); then remained stable. Renal artery blood flow, as determined by Doppler ultrasonography, was reduced from 352.5 +/- 56.5 to 157.3 +/- 53.7 cm/sec at 1 month after stenting (P < .0001). Renal function improved after stenting (serum creatinine 2.2 +/- 1.4 mg/dL preinsertion versus 1.72 +/- 1.05 at 3 years). In conclusion, in cases of severe or recurrent TRAS, stenting of the renal artery has proved to be an effective therapeutic tool. This method, which has low procedure costs and an extremely low complication rate has proved to be safe and to offer the potential of preserving luminal patency, improving the long-term efficacy of percutaneous angioplasty.

Blood Pressure↗
PubMed2005

The changing role of progesterone in preterm labour.

Progesterone is an essential hormone in the process of reproduction. It is involved in the menstrual cycle, implantation and is essential for pregnancy maintenance. Although the pharmacokinetics and pharmacodynamics of progesterone have been well studied, and since 1935 it has been synthesised and is now available commercially, its use in the pathophysiology of pregnancy remains controversial. One of these concerns is the way in which the hormone is administered, with parenteral use proving the best way to obtain optimal plasma levels. Another concern is the paucity of randomised controlled trials and the different dosages and populations studied. As a result, the therapeutic application of progesterone in pregnancy is restricted to the prevention and treatment of threatened miscarriage, recurrent miscarriage and preterm birth. Progesterone is efficacious when continuation of pregnancy is hampered by immunological factors, luteinic and neuroendocrine deficiencies and myometrial hypercontractility. This may explain the reduction in the incidence of preterm birth in high risk pregnant women using high-dosage prophylactic progesterone.

Abortion, Habitual↗
PubMed2004

The predictive localizing value of tonic limb posturing in supplementary sensorimotor seizures.

OBJECTIVE: To determine whether early tonic limb posturing is reliable in lateralizing or localizing of the seizure generator in 14 patients with pharmacoresistent supplementary sensorimotor area (SSMA) seizures. METHODS: All patients underwent high-quality MRI scans and stereo-EEG recordings. RESULTS: The SSMA seizure semiology predicted focal or regional ictal onset in the SSMA in six (43%) patients: Three had a focal SSMA seizure onset, and three had a regional seizure onset with involvement of one SSMA plus adjacent neocortex. The eight remaining patients had diffuse uni- or bilateral seizure onset. Eight of 14 patients underwent a frontal or central cortical resection, but a good outcome was seen in only 3: 2 with no SSMA resection and 1 with an extensive central removal. CONCLUSIONS: SSMA semiology is suggestive of early involvement of this region but is by no means a reliable indicator that the primary SSMA contains the seizure focus.

Adolescent↗
PubMed2004

A simple method to estimate photosynthetic radiation use efficiency of canopies.

BACKGROUND AND AIMS: Photosynthetic radiation use efficiency (PhRUE) over the course of a day has been shown to be constant for leaves throughout a general canopy where nitrogen content (and thus photosynthetic properties) of leaves is distributed in relation to the light gradient. It has been suggested that this daily PhRUE can be calculated simply from the photosynthetic properties of a leaf at the top of the canopy and from the PAR incident on the canopy, which can be obtained from weather-station data. The objective of this study was to investigate whether this simple method allows estimation of PhRUE of different crops and with different daily incident PAR, and also during the growing season. METHODS: The PhRUE calculated with this simple method was compared with that calculated with a more detailed model, for different days in May, June and July in California, on almond (Prunus dulcis) and walnut (Juglans regia) trees. Daily net photosynthesis of 50 individual leaves was calculated as the daylight integral of the instantaneous photosynthesis. The latter was estimated for each leaf from its photosynthetic response to PAR and from the PAR incident on the leaf during the day. KEY RESULTS: Daily photosynthesis of individual leaves of both species was linearly related to the daily PAR incident on the leaves (which implies constant PhRUE throughout the canopy), but the slope (i.e. the PhRUE) differed between the species, over the growing season due to changes in photosynthetic properties of the leaves, and with differences in daily incident PAR. When PhRUE was estimated from the photosynthetic light response curve of a leaf at the top of the canopy and from the incident radiation above the canopy, obtained from weather-station data, the values were within 5 % of those calculated with the more detailed model, except in five out of 34 cases. CONCLUSIONS: The simple method of estimating PhRUE is valuable as it simplifies calculation of canopy photosynthesis to a multiplication between the PAR intercepted by the canopy, which can be obtained with remote sensing, and the PhRUE calculated from incident PAR, obtained from standard weather-station data, and from the photosynthetic properties of leaves at the top of the canopy. The latter properties are the sole crop parameters needed. While being simple, this method describes the differences in PhRUE related to crop, season, nutrient status and daily incident PAR.

Juglans↗
PubMed2004

Donor characteristics can influence overall transplant activities: the Italian experience.

The notable increase in organ donations and transplants in Italy in recent years has lead to the development of an atypical approach to kidney transplantation. All propitious considerations left aside regarding the organ donation rate which has placed Italy among the European leaders, a careful comparative evaluation of the data taken from Italian and international registries demonstrates that renal transplantations in Italy have not shared the same significant growth. The typology of the donors has influenced in a decisive way not only the number of renal transplantations, but also the access to transplant for some age groups and probably even the quality and cost. The overall view which emerges is complex and somewhat contradictory, but we believe that this perspective can furnish solid arguments for choices that need not to be delayed for the living donor transplant, the divulgence of a donation culture in the population, and the criteria for the allocation of the organs.

Cadaver↗
PubMed2004

Excellent outcome of renal transplantation using single old kidneys in old recipients.

Aim of this monocentric study is to compare the outcome of 101 renal transplants performed in patients older than 55 years with single kidney retrieved from donors older than 50 years, with 263 transplants performed in patients younger than 55 years transplanted with young kidneys. Delayed graft function (DGF) had similar incidence (24 vs 23%). Acute rejections (AR) were fewer in younger recipients without statistical significance. A 6-month serum creatinine < 130 mmol/L was less frequent in older recipients (RR 1.20; p=0.004). 5-year patient survival rate was lower in older patients (80.6% vs 92.6%; p=0.009). Crude 5-year graft survival rate was lower in older recipients (68.5% vs 84.5%; p=0.004). Adjusting for death with functioning kidney 5-year graft survival was still, but not significantly, lower in older recipients (82.8% vs 90%; p=NS). This data outline that graft survival rate must be always adjusted for death with functioning grafts and that excellent outcomes with a 5-year graft survival, higher that 80% can be obtained in old patients using single cadaveric kidneys.

Aging↗
PubMed2004

Younger dialytic patients are really at risk to be not transplanted. The Tuscany experience.

The huge increase in organ donation (27.2 pmp in 2002), that characterized our regional transplant program was mainly due to the increase of marginal (older) donors. As allocating organs coupling donor and recipient age is mandatory, aim of this study was to verify the consequences of such retrieval policy over the renal transplant activity. According our longitudinal data younger uremic patients in Tuscany waiting list for transplantation, have the lowest chance to receive kidney transplantation, mainly with respect to older patients that are easily removed from the waiting list. This unfair condition need to be corrected either by promoting living donation, either increasing cadaveric donation from younger donors.

Adolescent↗
PubMed2003

Intractable temporal lobe epilepsy with rare spikes is less severe than with frequent spikes.

OBJECTIVE: To analyze clinical, electrophysiologic, and neuroradiologic characteristics of a group of patients with nonlesional intractable temporal lobe epilepsy (TLE) and rare or absent interictal epileptiform abnormalities (IEA). METHODS: Between 1990 and 2000, 31 patients (11 men; mean +/- SD age 34.3 +/- 11.7 years) with nonlesional intractable TLE were consecutively selected on the basis of the absence or paucity of IEA (<1/h) on serial scalp EEG recording; these were defined as "oligospikers." The clinical and laboratory characteristics of oligospikers were compared with those of a group of 27 age-matched control subjects (10 men; mean +/- SD age 38.5 +/- 11 years), randomly selected from a pool of patients with nonlesional TLE with frequent IEA. RESULTS: Oligospikers showed a later age at seizure onset (mean +/- SD 19.1 +/- 14.4 versus 10.2 +/- 7.4 years; p = 0.004), lower monthly frequency of complex partial seizures (median 6 versus 12; p = 0.035), lower incidence of secondarily generalized tonic-clonic seizures (10 versus 81%; p < 0.001), and no status epilepticus (0 versus 22%) than control subjects. Also, hippocampal atrophy (HA) was less commonly found in oligospikers (55 versus 96%; p = 0.001). However, there were no differences between the two groups in the frequency of family history of epilepsy, risk factors, febrile convulsions, and type of medication. Twenty-three (74%) oligospikers and 25 (93%) control patients underwent either a selective amygdalohippocampectomy or corticoamygdalohippocampectomy. Excellent surgical outcome (Engel's Class Ia) was found in 14 of 23 (61%) oligospikers and 17 of 25 (67%) control patients. CONCLUSIONS: This study identified a subgroup of patients with nonlesional intractable TLE with no or few IEA. Oligospikers have a later age at seizure onset, less frequent and less severe seizures, besides a lower incidence of HA. The similarity of etiologic factors compared with patients with frequent IEA suggests that the rarity of spikes could reflect a disease not really distinct but less severe, even though still intractable and incapacitating enough to consider surgery. In spite of the absence or paucity of IEA, oligospikers have excellent surgical outcome.

Adult↗
PubMed2003

One-year posttransplant renal function is a strong predictor of long-term kidney function: results from the Neoral-MOST Observational Study.

BACKGROUND: Peritransplant risk factors influence short-term and long-term graft survival, and 1-year serum creatinine is known to predict long-term graft survival. To examine interrelationships between risk factors, renal function at 1 year, and long-term graft function in patients maintained on cyclosporine, we analyzed data collected from 10,692 de novo or maintenance renal transplant recipients in an ongoing international, prospective, observational study--Neoral-MOST (Multinational Observational Study in renal Transplantation). The effect of donor age, delayed graft function, acute rejection, donor type, panel-reactive antibodies, and previous graft on 1- and 5-year renal function and their relationship to 1-year serum creatinine was assessed. RESULTS: Donor age, delayed graft function, acute rejection, and donor type significantly increased the risk for serum creatinine > 130 micromol/L at 1 year posttransplant, and 1-year serum creatinine was the strongest predictor of 5-year renal function. After adjustment for 1-year serum creatinine, an ongoing influence was observed for donor age, donor type, and previous graft. Delayed graft function and acute rejection had a significant effect on serum creatinine at year 1 but no additional impact on long-term graft function. CONCLUSIONS: Serum creatinine at 1 year is influenced by risk factors known to affect overall graft survival and is predictive of 5-year renal graft function. The effects of delayed graft function and acute rejection appear to be limited to their influence on serum creatinine at 1 year, whereas donor type and previous graft predominantly affect later stages of graft life.

Creatinine↗
PubMed2003

Estimating photosynthetic radiation use efficiency using incident light and photosynthesis of individual leaves.

It has been theorized that photosynthetic radiation use efficiency (PhRUE) over the course of a day is constant for leaves throughout a canopy if leaf nitrogen content and photosynthetic properties are adapted to local light so that canopy photosynthesis over a day is optimized. To test this hypothesis, 'daily' photosynthesis of individual leaves of Solanum melongena plants was calculated from instantaneous rates of photosynthesis integrated over the daylight hours. Instantaneous photosynthesis was estimated from the photosynthetic responses to photosynthetically active radiation (PAR) and from the incident PAR measured on individual leaves during clear and overcast days. Plants were grown with either abundant or scarce N fertilization. Both net and gross daily photosynthesis of leaves were linearly related to daily incident PAR exposure of individual leaves, which implies constant PhRUE over a day throughout the canopy. The slope of these relationships (i.e. PhRUE) increased with N fertilization. When the relationship was calculated for hourly instead of daily periods, the regressions were curvilinear, implying that PhRUE changed with time of the day and incident radiation. Thus, linearity (i.e. constant PhRUE) was achieved only when data were integrated over the entire day. Using average PAR in place of instantaneous incident PAR increased the slope of the relationship between daily photosynthesis and incident PAR of individual leaves, and the regression became curvilinear. The slope of the relationship between daily gross photosynthesis and incident PAR of individual leaves increased for an overcast compared with a clear day, but the slope remained constant for net photosynthesis. This suggests that net PhRUE of all leaves (and thus of the whole canopy) may be constant when integrated over a day, not only when the incident PAR changes with depth in the canopy, but also when it varies on the same leaf owing to changes in daily incident PAR above the canopy. The slope of the relationship between daily net photosynthesis and incident PAR was also estimated from the photosynthetic light response curve of a leaf at the top of the canopy and from the incident PAR above the canopy, in place of that measured on individual leaves. The slope (i.e. net PhRUE) calculated in this simple way did not differ statistically from that calculated using data from individual leaves.

Adaptation, Physiological↗
PubMed2001

High cysteine levels in renal transplant recipients: relationship with hyperhomocysteinemia and 5,10-MTHFR polymorphism.

BACKGROUND: Long-term survival of renal transplant recipients seems to be influenced by the occurrence of thromboembolic complications and cardiovascular disease. Preliminary data available in the literature found high levels of cysteine (Cy) as a risk factor for deep venous thrombosis independently of high homocysteine (tHcy) levels, but no data are available about Cy levels in renal transplant recipients. METHODS: To investigate Cy, tHcy, and plasminogen activator inhibitor-1 (PAI-1) levels and the prevalence of 5,10-methylenetetrahydrofolate reductase (MTHFR) in renal transplantation, we studied 70 stable renal transplant recipients and 66 age- and sex-matched normal subjects as controls. RESULTS: Cy, tHcy, and PAI-1 levels were significantly higher in renal transplant recipients with respect to controls (Cy: 254 micromol/L [117-466] vs. 198 micromol/L [99-331], P<0.001; tHcy: 17.0 micromol/L [4.0-68] vs. 8.1 micromol/L [2.0-24.0], P<0.00001; PAI-1: 16.8 IU/ml [5.1-45.5] vs. 7.9 IU/ml [4.0-18.0], P<0.00001). High Cy levels were detected in 35.8% of patients. Hyperhomocysteinemia, both in the fasting state and postmethionine loading test, was diagnosed in 90% of cases. The odds ratios for Cy and tHcy levels within the fourth quartile with respect to the other quartiles were markedly increased in renal transplant recipients even after adjustment for prevalent cardiovascular risk factors, glomerular filtration rate, tHcy and, Cy, respectively (Cy: 29.0 micromol/L [95% CI 7.0-111]; tHcy: 29.9 micromol/L [95% CI 7.5-118.1]). Fasting tHcy levels correlated well with PAI-1 (r=0.65; P<0.0001) but not with Cy levels (r=0.10; P=0.4). The prevalence of the MTHFR 677TT genotype in renal transplant recipients was not significantly higher in patients than in controls (mutant allele frequency: 0.48 in patients and 0.47 in controls) and was associated with significantly higher fasting and postmethionine tHcy levels both in controls and patients. After 2 months of vitamin supplementation, tHcy (Pre: 17.0 micromol/L [4.0-68]; Post: 7.5 micromol/L [2.3-21.9]; P<0.0001) and PAI-1 levels (Pre: 16.8 IU/ml [5.1-45.5]; Post: 10 IU/ml [2.0-25]; P<0.001) were significantly decreased, whereas Cy levels showed a small decrease that did not reach statistical significance (Pre: 254 micromol/L [117-466]; Post: 209 micromol/L [168-300]; P=0.3). Patients with the MTHFR 677TT genotype had the major percentage of decrease of tHcy levels with respect to the other genotypes. CONCLUSION: In conclusion, this study demonstrates the presence of elevated Cy plasma levels in renal transplant recipients. Vitamin supplementation reduces tHcy but not Cy levels, and the amount of decrease seems to be influenced by the MTHFR genotype.

5,10-Methylenetetrahydrofolate Reductase (FADH2)↗
PubMed2001

Characterization of multidrug transporters in a normal renal tubular cell line resistant to doxorubicin. Multidrug transporters in the LLC-PK(1) cell line and its resistant counterpart.

LLC-PK(1) is a proximal tubular cell line derived from normal pig kidney which has a structure and function similar to those of renal proximal tubular cells and which expresses baseline levels of P-glycoprotein. We isolated by drug selection a doxorubicin-resistant cell line (LLC-PK(1)/ADR) that exhibited a multidrug-resistant phenotype; this cell line was characterized by reduced intracellular drug concentrations, an increased drug extrusion, and increased expression of a 170-kDa P-glycoprotein detected by Western blot analysis with monoclonal antibody C219. In addition, an increased expression of MDR1 mRNA was seen by reverse transcriptase-polymerase chain reaction. These results suggest that it is possible to induce the overexpression of P-glycoprotein by chronic treatment with doxorubicin in a normal cell line that physiologically expresses low levels of this protein. This multi-resistant cell line could provide an interesting model for studying the role of P-glycoprotein and the consequence of its induction in a normal tissue.

ATP Binding Cassette Transporter, Subfamily B, Mem↗