Biomedical subjects

V Parisi

Publications and source records attributed to V Parisi.

At least 19 recordsLinked to original sources

PubMed2002

Human serum albumin adsorption onto a-SiC:H and a-C:H thin films deposited by plasma enhanced chemical vapor deposition.

In the present paper, we report the study of the adsorption behavior of a model protein such as human serum albumin (HSA) onto surfaces of a-SiC:H and a-C:H thin films deposited by using the plasma-enhanced chemical vapor deposition (PECVD) technique. The surface composition and surface energy of the various substrates as well as the evaluation of the adsorbed amount of protein has been carried out by means of X-ray photoelectron spectroscopy (XPS) and contact angle measurements. It has been found that HSA tends to preferentially adsorb on Si-rich surfaces, as far as the relative amount of adsorbed HSA decreases with increasing S-C concentration. Preliminary elements of mechanistic models are proposed for the correlation between chemical factors and the observed protein adsorption behavior.

Adsorption↗

PubMed2001

Correlation between optical coherence tomography, pattern electroretinogram, and visual evoked potentials in open-angle glaucoma patients.

OBJECTIVE: [corrected] To correlate the nerve fiber layer (NFL) thickness and the visual function evaluated by electrophysiologic retinal and cortical responses assessed in open-angle glaucoma (OAG) eyes. DESIGN: Prospective case-control study. PARTICIPANTS: Thirty glaucoma patients (mean age, 47.1 +/- 7.15 years; refractive error range, +/- 2 spherical equivalent) with a mean deviation of computerized static perimetry (24/2 Humphrey, Dublin, CA) from -5 to -28 dB and intraocular pressure less than 21 mmHg on pharmacologic treatment and 14 age-matched control participants. METHODS: Nerve fiber layer thickness was measured by optical coherence tomography. Retinal and visual pathway function was assessed by simultaneously recording pattern electroretinograms (PERGs) and visual evoked potentials (VEPs) using high-contrast (80%) checkerboard stimuli (the single check edges subtend 15 minutes of the visual arc) reversed at the rate of two reversals per second. Linear regression analyses were adopted to establish the correlation between NFL thickness and PERG and VEP parameters. MAIN OUTCOME MEASURES: Nerve fiber layer thickness measurements in each quadrant (superior, inferior, nasal, and temporal) were taken and then averaged (12 values averaged) and identified as NFL overall, whereas the data obtained in the temporal quadrant only (three values averaged) were identified as NFL temporal. PERG P50 implicit time and P50-N95 amplitude and VEP P100 implicit time and N75-P100 amplitude were also measured. RESULTS: In OAG eyes, we found a significant (P < 0.01) reduction in NFL thickness in both NFL overall and NFL temporal evaluations with respect to the values observed in control eyes. PERG and VEP parameters showed a significant (P < 0.01) delay in implicit time and a reduction in peak-to-peak amplitude. In OAG eyes, the NFL overall and NFL temporal values were significantly correlated (P < 0.01) with the PERG P50 implicit time and P50-95 peak-to-peak amplitude. No correlations (P > 0.01) between NFL values and VEP parameters were found. CONCLUSIONS: There is a correlation between PERG changes and NFL thickness, but there is no correlation between VEP changes and NFL thickness in patients affected by OAG.

Adult↗

PubMed2001

Evaluation of primary surgical procedures for retinal detachment with macular hole in highly myopic eyes: a comparison [corrected] of vitrectomy versus posterior episcleral buckling surgery.

PURPOSE: To evaluate postoperative outcomes between pars plana vitrectomy (PPV) and posterior episcleral buckle procedure (PEBP) in myopic eyes with retinal detachment (RD) and macular hole (MH). DESIGN: Retrospective nonrandomized comparative interventional trial. PARTICIPANTS AND INTERVENTION: The study included 30 phakic, highly myopic eyes (from 19-30 negative diopters) of 30 patients with an RD and MH. The patients were divided into two groups: They were assigned to PPV (15 eyes, group A) or to PEBP (15 eyes, group B). No significant (P > 0.01) differences in preoperative visual acuity (VA) between group A and group B eyes were found. Follow-up was 12 months. MAIN OUTCOME MEASURES: Anatomic attachment of the retina was determined, and VA was measured. RESULTS: Retinal reattachment was obtained on 11 of 15 (73.3%) eyes of group A and on 14 of 15 (93.3%) eyes of group B. In group A eyes the VA was substantially unmodified after surgical treatment, whereas in group B eyes the VA observed after surgical treatment increased significantly (P < 0.001) with respect to the preoperative values. CONCLUSIONS: PEBP resulted in better postoperative anatomic and functional results compared with PPV in eyes with extreme degrees of myopia, pronounced posterior staphyloma, and posterior vitreous schisis affected with RD caused by MH.

Adult↗

PubMed2001

Metal concentrations in Helix pomatia, Helix aspersa and Arion rufus: a comparative study.

In this study we evaluated the differences between concentrations of copper, iron, zinc, manganese, lead and cadmium in three terrestrial gastropods: Helix pomatia, Helix aspersa and Arion rufus, collected in a semi-rural location in Northern Italy. Metal concentrations in the foot and in the digestive gland were measured. In the hepatopancreas, copper and zinc did not differ significantly in the three species; the levels of copper were also similar in the foot. In comparison to Helix sps., A. rufus demonstrated lower concentrations of manganese and cadmium in the hepatopancreas and higher concentrations in the foot. In the slug the mucus produced in the foot could represent an efficient elimination mechanism of some elements. We also investigated correlations between the trace element content in the soft tissues and the mollusk size (weight of the body and height of the shell).

Animals↗

PubMed2001

Impaired visual function in glaucoma.

OBJECTIVE: This work aims to evaluate whether glaucomatous visual field defects could be related to an impaired retinal function, to a delayed neural conduction in postretinal visual pathways, or both. METHODS: Visual field by Humphrey perimeter (central 24-2 threshold test) and simultaneous recordings of visual evoked potential (VEP) and pattern electroretinogram (PERG) were assessed in 21 subjects with open angle glaucoma (POAG) and in 15 age-matched controls (C). RESULTS: VEP: in POAG eyes we found P100 latency significantly (P<0.01) delayed when compared with controls and correlated with mean deviation (index of global visual field damage, MD) of 24-2 Humphrey perimetry (P<0.001); the P100 amplitudes were significantly (P<0.01) lower in POAG eyes than in control eyes and correlated with MD (P<0.001). PERG: POAG eyes showed P50 latency significantly (P<0.01) delayed when compared with controls and correlated with MD (P=0.002); the P50 and N95 amplitudes were significantly (P<0.01) lower in POAG than in control eyes and correlated with MD (P50: P=0.006; N95: P=0.002). Retinocortical time (RCT: difference between VEP P100 and PERG P50 latencies) and latency window (LW: difference between VEP N75 and PERG P50 latencies) were significantly (P<0.01) longer in POAG eyes than in control eyes and correlated with MD (RCT: P<0.001; LW: P<0.001). No significant correlations (P>0.05) were found between electrophysiological parameters and the corrected pattern standard deviation (index of localized visual field damage) of 24-2 Humphrey perimetry. CONCLUSION: In patients with open angle glaucoma the reduction of the index of global visual field damage (MD) could be ascribed to two sources of functional impairment: one retinal (impaired PERG) and one postretinal (delayed RCT and LW). In the postretinal impairment, a postsynaptic degeneration at the level of the lateral geniculate nucleus could be suggested.

Electroretinography↗

PubMed2001

Morphological and functional retinal impairment in Alzheimer's disease patients.

OBJECTIVE: Our study aims to assess the optic nerve fiber layer thickness in vivo, the function of the innermost retinal layer and whether a correlation exists between morphological and functional parameters in patients affected by Alzheimer's Disease (AD). METHODS: Seventeen AD patients (mean age 70.37+/-6.1 years, best corrected visual acuity >8/10 with refractive error between +/-3 sf, intra-ocular pressure (IOP)<18 mmHg) were enrolled. They were compared to 14 age-matched controls. Nerve fiber layer (NFL) thickness was measured by optical coherence tomography (OCT). Three different measurements in each quadrant (superior, inferior, nasal, and temporal) were taken and averaged. The data in all quadrants (12 values averaged) were identified as NFL Overall. Retinal function was assessed by pattern electroretinogram (PERG) recordings using high-contrast (80%) checkerboard stimuli subtending 15 min of the visual arc and reversed at the rate of two reversals/s. RESULTS: In AD eyes, there was a significant (P<0.01) reduction in NFL thickness in each quadrant and in the NFL Overall evaluation compared with the values observed in control eyes. PERGs showed a significant (P<0.01) delay in N35, P50 and N95 implicit times, and reduction in N35-P50 and P50-N95 amplitudes. NFL Overall values were significantly correlated (P<0.01) to the PERG P50 and N95 implicit times and P50-N95 amplitude. No correlations (P>0.01) between NFL values and other PERG parameters (N35 implicit time, N35-P50 amplitude) were found. CONCLUSIONS: Our results suggest that in AD patients, there is a reduction of NFL thickness evaluated in vivo by OCT and this morphological abnormality is related to a retinal dysfunction as revealed by abnormal PERG responses.

Aged↗

PubMed2001

Electrophysiological evaluation of the macular cone adaptation: VEP after photostress. A review.

In the present review, the methodologies and clinical applications of the visual evoked potentials (VEPs) after photostress, will be described. Photostress induces transient VEP changes consisting of an increase in response latency and a decrease in amplitude. When serial VEP recordings are obtained at discrete time intervals (i.e., every 20 s) after bleaching, the recovery of VEP waveform can be evaluated. The time needed for the VEP to recover to the pre-bleach, baseline status (recovery time after photostress) ranges in normal subjects between 68 and 78 s. Patients with different pathologies (maculopathies, ocular hypertension and glaucoma, diabetes with or without retinopathy, multiple sclerosis with optic neuritis) showed an abnormal response after photostress (higher increase in latency and decrease in amplitude and longer recovery time) with respect to age-matched controls. Our results indicate that the VEPs after photostress represent an objective, although not specific, index of the dynamic properties of macular performance after exposure to intense light stimulation.

Adaptation, Ocular↗

PubMed2001

DNA quadruplexes and dynamical genetics.

In a recent paper, we have put forward the hypothesis that there exist smart purposive mechanisms - tandem repeat length managers - which regulate the length of some tandem repeat, or cause rearrangements, and are almost always driven by some variable number tandem repeat. We have called the framework in which such mechanisms act 'dynamical genetics'. The purpose of this paper is to contribute to lay the foundations of a molecular study of the above mechanisms, by proposing a hypothesis, based on various kinds of supporting evidence and plausibility arguments, about the special importance of DNA quadruplexes for dynamical genetics, and by considering the involved enzymes. This hypothesis states that a tandem repeat length manager acts almost always by monitoring a DNA tract that has the characteristics of being a variable number tandem repeat and/or forming a DNA quadruplex, and that it is almost always driven by at least one of them.

Aging↗

PubMed2001

On new hypotheses about autosomal dominant polycystic kidney disease type 1.

The purpose of this paper is to suggest a partial explanation of the aetiology of autosomal dominant polycystic kidney disease type 1, one of the most common genetic diseases in humans. To this aim we put forward a number of interconnected ideas, based on a number of experimental evidences and plausibility arguments. We stress the major role played by the instability of some genomic tandem repeats, together with the DNA structures known as quadruplexes, the pseudogenes and the gene conversion. The model we propose can be considered a multi-hit generalization of the well-known two-hit model, a generalization that could well have a validity also outside the specific context. We finally provide an indication of the likely guilty DNA segment for the above disease, and we propose a possible simple experimental line of action aimed to confirm or disproof our suggestion.

Age of Onset↗

PubMed2001

Impact of surgical treatment on quality of life of patients with gastrointestinal tumors.

Quality-of-life assessment is becoming an important concern even of surgeons. The new trend applies specifically to surgical oncology, where particular attention is now being paid to the outcome of surgical treatment. Gastrointestinal cancers are heterogeneous in their presentation and in treatment, but they share common aspects related to the surgical approach. A functional outcome is fundamental in all the operations performed for gastrointestinal cancers and many improvements have been made thanks to the increased rate of conservative approaches and the amelioration of the technology applied to surgery. The measurement of the surgical outcome and the methods to be applied is still undergoing extensive evaluation but the flourishing interest in the issues concerning quality of life all over the surgical community will rapidly lead to a better definition of goals and results.

Colorectal Neoplasms↗

PubMed2001

Effects of perceptions and mentorship on pursuing a career in academic medicine in obstetrics and gynecology.

PURPOSE: To understand the perceptions of residents and Fellows in obstetrics and gynecology about the impacts of race or ethnicity, gender, and mentorship experiences on pursuing careers in academic medicine. METHOD: Two surveys were administered: one to a sample of 2,000 Fellows of the American College of Obstetricians and Gynecologists, and one to the 4,814 obstetrics and gynecology residents taking the 1998 in-training examination. The questionnaires asked about demographics, perceptions about careers in academic medicine, and residents' experiences with mentorship. RESULTS: Response rates were 96.8% for residents and 40.6% for FELLOWS: Of the residents, 26.1% indicated they would not consider a career in academic medicine. First-year women residents were more inclined to pursue careers in academic medicine than were first-year men (p =.042), but their interest declined during residency. Women residents (43%)-especially minorities-felt that men were mentored and recruited more for faculty positions, while men (38%) felt that women were mentored and recruited more. Fellows' reports of recruitment did not differ by gender. Most white residents did not perceive racial or ethnic bias in mentoring or recruiting, while most non-white residents did. Almost one third of non-white women residents felt that supervisors were more likely to condescend to women and minority individuals. CONCLUSIONS: It is likely that neither men nor women residents in obstetrics and gynecology receive adequate mentorship for careers in academic medicine. Perceptions of bias are a serious barrier to developing racial, ethnic, and gender diversity in leadership positions.

Attitude of Health Personnel↗

PubMed2001

Early postoperative enteral nutrition improves gut oxygenation and reduces costs compared with total parenteral nutrition.

OBJECTIVE: To evaluate the potential clinical, metabolic, and economic advantages of enteral nutrition over total parenteral nutrition. DESIGN: Prospective, randomized clinical trial. SETTING: Department of surgery in a university hospital. PATIENTS: Two hundred and fifty-seven patients with cancer of the stomach (n = 121), pancreas (n = 110), or esophagus (n = 26) were randomized to receive postoperative total parenteral nutrition (TPN group, n = 131) or early enteral nutrition (EEN group, n = 126). The nutritional goal was 25 kcal/kg/day. The two nutritional formulas were isocaloric and isonitrogenous, and they were continued until oral intake was at least 800 kcal/day. MEASUREMENTS: Morbidity, mortality, length of hospital stay, and treatment costs were evaluated in all patients. In 40 consecutive patients, selected nutritional, immunologic and inflammatory variables were studied. Moreover, intestinal oxygen tension was evaluated by micropolarographic implantable probes. MAIN RESULTS: The nutritional goal was reached in 100/126 (79.3%) patients in the EEN group and in 128/131 (97.7%) patients in the TPN group (p <.001). In the EEN group, hyperglycemia (serum glucose, >200 mg/dL) was observed in 4.7% of the patients vs. 9.1% in the TPN group (p = NS). Alteration of serum electrolyte levels was 3.9% in the EEN group vs. 13.7% in the TPN group (p <.01). No significant difference was found in nutritional, immunologic, and inflammatory variables between the two groups. The overall complication rate was similar (40.4% for TPN vs. 35.7%, for EEN; p =.52). No difference was detected for either infectious or noninfectious complications, length of hospital stay, and mortality. From postoperative day 5, intestinal oxygen tension recovered faster in the EEN group than in the TPN group (43 +/- 5 mm Hg vs. 31 +/- 4 mm Hg at day 7; p <.001). EEN was four-fold less expensive than TPN ($25 vs. $90.60/day, respectively). CONCLUSION: EEN represents a rational alternative to TPN in patients who undergo upper gastrointestinal tract surgery for cancer and who clinically require postoperative artificial nutrition.

Aged↗

PubMed2001

Saccadic eye movement and visual pathways function in diabetic patients.

We assessed saccadic eye movements (SEM) and the visual evoked potentials (VEP) with the aim to evaluate whether a correlation exist between SEM and visual pathways function, in insulin-dependent diabetes mellitus (IDDM) patients. In IDDM patients we observed significantly longer SEM latency, while SEM velocity and accuracy were similar to those of the controls; VEP showed a significant delay of the latencies and significant reduction of the amplitudes in IDDM patients no relationship between SEM and VEP parameters were found. In conclusion SEM latency delay suggest an impairment of the saccadic eye movement system, while impaired VEP may be ascribed to a dysfunction of the visual pathways. The lack of correlation between VEP impairment and SEM latency delay suggests that in our IDDM patients the delay of saccadic latency could be ascribed to a difuse neuronal problem exceeding the visual pathways disfunction.

Adult↗

PubMed2000

Visual electrophysiological responses in subjects with cerebral autosomal arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).

OBJECTIVES: To evaluate visual electrophysiological responses in subjects with cerebral autosomal arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). METHODS: Three subjects (one male and two females, mean age 55.3+/-2.9 years) belonging to an Italian family already diagnosed with CADASIL through clinicopathological and genetic studies and 14 control subjects (6 males and 8 females, mean age 52.7+/-3.6 years) were enrolled in the study. Flash electroretinogram (ERG), oscillatory potentials (OPs) and simultaneous recordings of pattern electroretinogram (PERG) and visual evoked potentials (VEPs) were assessed in all 3 subjects with CADASIL and age-matched controls. RESULTS: Subjects with CADASIL showed: reduced ERG, OP and PERG (N35-P50, P50-N95) amplitudes with respect to our normal limits; delayed PERG (N35, P50) and VEP (P100) implicit times when compared with our normal limits; and VEP (N75-P100) amplitudes and retinocortical times within our normal limits. CONCLUSIONS: Subjects with CADASIL present a dysfunction in the outer, middle and innermost retinal layers when the index of neural conduction in the postretinal visual pathways is normal. The delay in visual cortical responses observed in subjects with CADASIL may be ascribable to retinal impairment with a possible functional sparing of the postretinal visual structures.

Dementia, Multi-Infarct↗

PubMed2000

A new look at the challenging world of tandem repeats.

Recent research has shown a correlation between some genetic diseases and genomic sequences tandemly repeated a variable and excessive number of times. The excessive number of tandem repeats is usually caused by a progressive expansion, generally considered as purely harmful. We put forward a number of hypotheses: the main one is that the number of repeats has normally a specific significance, and that there exist purposive mechanisms having as a primary function the management of tandem repeats length; such a function is generally useful and only rarely may it become harmful, because of some malfunctioning. These hypotheses are suggested by plausibility arguments, and are supported by a number of recent experimental results. They could provide a simple and unifying explanation of many pathological and non-pathological phenomena replacing many ad hoc assumptions. We finally propose to call the study of the above tandem repeat managing mechanisms 'dynamical genetics'.

Aging↗

PubMed2000

The role of chemotherapy in the management of gastric cancer.

Despite a marked decline in the incidence of gastric carcinoma in Western countries, the majority of patients presents with advanced inoperable tumors. In this setting, usually the aim of therapy is palliation, with the exception of chemotherapy administered in the attempt to downstage the tumor and to facilitate potentially curative surgery in patients with locally advanced nonmetastatic disease. This review will focus on the use of chemotherapy for advanced gastric cancer and after curative surgery, providing an overview of future directions for clinical research: preoperative (neoadjuvant) systemic chemotherapy, intraperitoneal treatment, and newer drugs.

Antimetabolites, Antineoplastic↗

PubMed2000

Detection of circulating tumor cells in carcinoma patients by a novel epidermal growth factor receptor reverse transcription-PCR assay.

The epidermal growth factor receptor (EGFR) is overexpressed in 50-70% of human primary breast, lung, and colon carcinomas, whereas it is not usually expressed in hematopoietic cells. We developed a novel reverse transcription-PCR (RT-PCR)-Southern blot assay for the detection of circulating, EGFR mRNA-expressing tumor cells in carcinoma patients. The assay was set up by increasing the amount of cDNA step by step in the PCR reaction. The highest sensitivity and specificity were found when using 800 ng of cDNA in the PCR reaction. Peripheral blood samples from 91 patients with either colon (38), lung (30), or breast (23) carcinomas and from 38 healthy volunteers were analyzed. EGFR transcripts were found in 44 of 75 (59%) patients with metastatic carcinoma and in 4 of 38 (10.5%) healthy donors (P < 0.001; chi2 test). The expression of EGFR, cytokeratin 19, and carcinoembryonic antigen mRNA in blood samples from patients with metastatic colon carcinoma was compared. EGFR, cytokeratin 19, and carcinoembryonic antigen transcripts were found in 8 of 11 (73%), 3 of 11 (27%), and 5 of 11 (45%) patients, respectively. Furthermore, two of seven (29%) Dukes' B and five of nine (55%) Dukes' C colon carcinoma patients were found to express EGFR mRNA in the peripheral blood. All patients that expressed EGFR transcripts in the peripheral blood were found to express the EGFR protein in the corresponding primary carcinoma, as assessed by immunohistochemistry. These data suggest that the EGFR assay that we developed is a highly specific and sensitive technique to detect circulating tumor cells in patients affected by different carcinoma types.

Breast Neoplasms↗

PubMed1999

A novel parameter to estimate the minimum number of bound ligands needed to activate an ion channel.

We consider the Hill coefficient obtained from concentration-response curves and we stress the differences between the use of binding and the use of current for the response. We first show that in order to estimate the cooperativity of binding sites one must use the coefficient obtained from the binding curves and not that obtained from the current curves. For what concerns the estimation of the minimum number of bound ligands needed to activate the channel, while the coefficient obtained from the binding is simply not applicable, we show that the coefficient obtained from the current is not appropriate. We finally introduce a novel parameter that predicts the number of ligand molecules required to open the channel from current measurements at very low ligand concentration. The above considerations are exemplified by a few theoretical models.

Animals↗