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Biomedical subjects

R Pace

Publications and source records attributed to R Pace.

At least 19 recordsLinked to original sources
PubMed2003

A simple HPLC-UV method for the assay of ginkgolic acids in Ginkgo biloba extracts.

Extracts from the leaves of Ginkgo biloba are among the most widely used phytotherapeutics. Some alkylphenols (ginkgolic acids, cardanols and cardols) have been described as potentially hazardous constituents in Ginkgo extracts. Accordingly, a requirement for a maximum concentration of ginkgolic acids has been proposed in the UE and US pharmacopoeias Ginkgo monographs establishing a limit value of 5 ppm. A novel HPLC-UV method, developed by the use of HPLC-APCI-MS HPLC-DAD techniques and allowing the identification of ginkgolic acids and related phenols, is described. The new analytical method, not requiring enrichment procedures, can be used for the quantification of ginkgolic acids in Ginkgo extracts.

Chemistry Techniques, Analytical↗
PubMed2003

Psychopathological assessment in children affected by Duchenne de Boulogne muscular dystrophy.

BACKGROUND: Several studies on the intelligence of children suffering from Duchenne muscular dystrophy (DMD) found impairments in linguistic functions, memory and affective development. Memory deficit mainly involves long-term memory; short-term memory impairment was also present, even if less frequently. Some studies tried to establish a correlation between the distal deletion of the dystrophin gene and low intelligence levels. METHODS: The present study investigated the cognitive, emotional and relational states in a group of DMD children. The patients were selected on the basis of physical examination, muscle biopsy, histochemical analysis, genetic testing, regular schooling. Molecular genetic testing detected a deletion in 2 high frequency deletion regions in all subjects. The following psychodiagnostic tests were used for assessment: WISC-R, Spontaneous Drawing, Draw-A-Person test, Family Drawing, Thematic Apperception test and Rorschach test. RESULTS: No impairment of the intellectual function was detected in the group of children we examined; only 2 subjects had a total IQ below average. Instead, psychic disorders were detected such as proneness to isolation, self-depreciation, past experiences of marginalization, minor depressive symptoms, insecurity signs, hypochondriac worries and high level of anxiety. In addition children exhibited poor adaptation to the environment and labile affectivity, scarcely controlled by the higher conscious levels. CONCLUSIONS: These disorders are often a dynamic prolongation of a psychological process starting when the diagnosis is made and continuing in a slow and latent fashion throughout the evolution of the disease.

Anxiety↗
PubMed2002

Identification of Ruscus steroidal saponins by HPLC-MS analysis.

A novel HPLC-UV method has been developed for the fingerprint analysis of the steroidal saponins in the rhizomes of three Ruscus species (Ruscus aculeatus, Ruscus hypoglossum and Ruscus colchicus). Saponins were identified by HPLC-ESI-MS. During the study a new major saponin was detected in the rhizomes of R. hypoglossum and R. colchicus. The structure of the new compound was defined as 1-O-[alpha-L-rhamnopyranosyl-(1-->2)-6-O-acetyl-beta-D-galactopyranosyl]-1beta,3beta,22xi,26-tetrahydroxy-furost-5(6)-en-26-O-beta-D-glucopyranoside (8) by spectral analysis.

Chromatography, High Pressure Liquid↗
PubMed2000

Orientation dependence of NMR relaxation time, T(1rho), in lipid bilayers.

The orientation dependence of the low frequency NMR relaxation time, T(1rho), of protons in aligned phospholipid bilayers was measured using 13C cross polarisation and direct proton experiments. The contribution of intra- and inter-molecular interactions to proton T(1rho) was determined by using dimyristoyl phosphatidylcholine (DMPC) with one hydrocarbon chain deuterated and dispersed in perdeuterated DMPC. The results indicated that intramolecular motions on the kHz timescale were the major cause of T(1rho) relaxation in phospholipid bilayers.

Carbon Isotopes↗
PubMed2000

Characterization of proanthocyanidins from grape seeds.

Leucoselect (grape seed selected proanthocyanidins) was analyzed. HPLC thermospray mass spectrometry (TSP-MS) allowed the detection of monomeric flavan-3-ols and dimeric proanthocyanidins. Fractionation over Sephadex LH-20 resin and analysis of the isolated fractions by gel permeation chromatography (GPC) and electrospray mass spectrometry (ESI-MS) led to the complete characterization of the proanthocyanidin constituents of Leucoselect. The analysis revealed the presence of approximately 15% of (+)-catechin (1) and (-)-epicatechin (2), 80% of (-)-epicatechin 3-O-gallate (3), dimers, trimers, tetramers and their gallates and 5% of pentamers, hexamers, heptamers and their gallates.

Anthocyanins↗
PubMed1999

Liquid chromatography-electrospray mass spectrometric identification of ginsenosides in Panax ginseng roots.

A high-performance liquid chromatographic method was developed for electrospray mass spectrometric analysis of ginsenosides in Panax ginseng roots. The analyses were performed on a reversed-phase C18 column using a binary eluent (aqueous 8 mM NH4OAc, buffered to pH 7 with NH4OH-acetonitrile) under gradient conditions. Twenty-five ginsenosides could be separated and detected. The mass spectra obtained provided information on their molecular masses. A MS-MS experiment was undertaken in order to determine the sugar unit sequences and the aglycone moieties.

Chromatography, High Pressure Liquid↗
PubMed1999

Deuteration effects on the in vivo EPR spectrum of the reduced secondary photosystem I electron acceptor A1 in cyanobacteria.

The photoreduction of the secondary PSI electron acceptor A1 in vivo has recently been detected via X-band EPR spectroscopy in intact spinach chloroplasts and in marine cyanobacteria Synechococcus PCC 7002 [Klughammer, C., and Pace, R. J. (1997) Biochim. Biophys. Acta 1318, 133-144]. A further study of the A1- EPR spectrum of Synechococcus PCC 7002 at room temperature with higher-field resolution revealed partially resolved hyperfine structure which was dominated by 0.4 mT splittings of three equivalent protons. The hyperfine splitting was not significantly affected by incubation of the cyanobacteria in 2H2O medium for 20 h, but was absent in fully deuterated cyanobacteria that were grown in 2H2O medium. Anisotropic g-factors consistent with a phylloquinone radical were derived by spectra simulation. Biosynthetic protonation of quinones via the CH3 donor L-methionine in deuterated cells maintained hyperfine structure in the A1- spectrum, indicating the incorporation of CH3 groups in 60% of the deuterated, photoactive A1 molecules. Conversely, biosynthetic quinone deuteration via L-[methyl-d3]methionine in protonated cells led to the loss of the 0. 4 mT splittings in 54% of the A1 molecules. These observations confirm the conclusion of Heathcote et al. [(1996) Biochemistry 35, 6644-6650] of the identity of EPR-detected, photoreduced A1- in vivo with a phylloquinone (vitamin K1) radical in PSI. The partially resolved hyperfine structure of the A1- spectrum indicates an altered spin distribution in the bound vitamin K1- radical in vivo compared to that of unbound vitamin K1- in vitro.

Cyanobacteria↗
PubMed1998

A SEM study of in vivo accuracy of the Root ZX electronic apex locator.

Twenty-nine unprepared, vital teeth were used to evaluate the accuracy of the Root ZX in locating the root canal foramen. After extraction of the teeth, a scanning electron microscope analyzed the relation of the file tip to the foramen. The sample was divided into two groups (Group A and Group B) according to the presence of a normal apical foramen (along the root main axis) or of a lateral foramen (deviating from the root main axis). With a tolerance level of +/- 0.5 mm, a clinical accuracy rate of 82.75% was recorded in the total sample. With a +/- 1.0-mm tolerance level, an accuracy of 100% was found. The error in locating the apex was significantly smaller in cases with a normal apical foramen (Group A) than in cases with a lateral foramen (Group B) (p < 0.001). An accuracy of 100% at the +/- 0.5-mm tolerance level was registered in Group A.

Dental Instruments↗
PubMed1997

A phase I trial of 5-day chronomodulated infusion of 5-fluorouracil and 1-folinic acid in patients with metastatic colorectal cancer.

The aim of this phase I study was to establish the maximum tolerated dose (MTD) of 5-fluorouracil (5-FU), administered as a 5-day chronomodulated infusion in combination with 1-folinic acid (FA) to ambulatory metastatic colorectal cancer patients. Consecutive cohorts of 6 patients were given 5-FU and FA infusions from 10.00 p.m. to 10.00 a.m. with peak delivery at 4.00 a.m. by means of a multichannel programmable pump. The FA dose was always the same (150 mg/m2/d). For the first cohort, the 5-FU dose level was 600 mg/m2/d at the first course, escalated by 100 mg/m2 for each subsequent cohort. Intrapatient dose was also escalated by 100 mg/m2 if toxicity was less than grade 2. The courses were repeated every 3 weeks. Thirty-four patients (17 previously treated) received a total of 154 courses. Dose-limiting toxicity consisted of stomatitis and diarrhoea. No significant haematological, cutaneous or cardiac toxicity was encountered. The MTD of 5-FU was reached at the fourth level (first course at 900 mg/m2/d equal to 4500 mg/m2/course) with 5-FU increased to 1100 mg/m2/d (5500 mg/m2/course) in 4 patients. The received 5-FU dose intensity (DI) over the first 3 courses at this level was 1318 mg/m2/week. Thirty-three patients were assessed for response. An objective response was achieved in 1 out of the 13 previously-treated and in 8 out of the 20 previously-untreated patients. The chronomodulated infusion of 5-FU at a dose of 900 mg/m2/d, together with FA at 150 mg/m2/d for 5 days, was safely delivered to out-patients with metastatic colorectal cancer. The low toxic profile and activity of this regimen in previously untreated patients deserves further exploration for the treatment of 5-FU-sensitive tumours.

Adenocarcinoma↗
PubMed1997

Demographic characteristics of the vision-disabled elderly.

PURPOSE: To profile certain demographic features of the low-vision population in Ontario, Canada. METHODS: Sixty-six optometrists or optometry centers, 8 ophthalmologists, and 23 Canadian National Institute for the Blind rehabilitation worker teams were recruited to the study. They were required to report on their low-vision examinations during a 3-year period. RESULTS: Reports from 4744 low-vision examinations were received. Of the patients examined, 71% were over age 65 (subsequently called seniors or elderly), and 55% were over age 75. Ninety percent of all the patients lived in households and 10% lived in institutions. Seniors made up 71% of the patients living in households and 88% of the patients living in institutions. Most of the seniors were women (65%), and 57% had functional limitations in addition to low vision, most commonly limitations in mobility, hearing, or agility. Age-related maculopathy was the primary diagnosis in 75% of seniors, and the most common secondary diagnosis was cataract (46%). The main objective for most elderly low-vision patients was to gain improvement in personal reading (75%). CONCLUSIONS: The vast majority of low-vision patients were elderly, the largest number being 75 to 84 years old. When older senior low-vision patients (> or = 85 years) were compared with younger seniors (65 to 74 years), the older seniors were more likely to be women, more likely to have additional functional limitations, more likely to live in an institution, and more likely to have age-related maculopathy and cataract. Whether some elderly low-vision patients may be helped by cataract surgery needs to be determined.

Adolescent↗
PubMed1995

Chronomodulated 5-day infusion of floxuridine and L-folinic acid in patients with advanced malignancies: a feasibility and tolerability study.

The best schedule for administering floxuridine (FUDR) has not yet been established. Duration of infusion, need (and dosage) of leucovorin (folinic acid, FA), and circadian timing need to be further specified. Nevertheless, FUDR delivery according to circadian rhythms has allowed increase of dose intensity without enhancing the side effects. A 5-day infusional schedule combining FUDR and L-FA was devised as an attempt to increase dose intensity and to provide therapy every 3 weeks to patients with advanced cancer. An ambulatory programmable-in-time pump was used for this purpose. Fourteen patients entered this trial. Two dose levels (mg/kg x 5 days) were evaluated: 0.5 mg/kg/day in six patients and 0.525 mg/kg/day in eight patients. Both patient groups received a concurrent infusion of L-FA 10 mg/m2/day i.v. The delivery patterns of both FUDR and L-FA varied sinusoidally during the 24 hours with a maximum at 18.00 hours. Courses were repeated every 3 weeks. Of 35 courses, treatment produced mucosites greater than grade 2 in only two of them. No severe diarrhea, the dose-limiting toxicity of FUDR when infused over 14 days, was encountered at the dose levels tested. This 5-day chronotherapy schedule allowed delivery of a larger amount of FUDR than the flat delivery described in a previous report. A daily dose of 0.525 mg/kg FUDR, combined with 10 mg/mg2 L-FA, with intraindividual dose escalation according to tolerance, is recommended for future investigations of the activity of this chronotherapy schedule.

Adult↗
PubMed1995

[Localization of the apical foramen using the newest electronic instruments: stereomicroscopy and SEM (scanning electron microscopy)].

Introduction of double impedence as new parameter in root canal length electronic measurement allowed first and second generation electronic apical localizers main problems overcoming: precision failure in presence of conducting fluids. Our study's purpose was an in vitro evaluation of two third generation instruments (Apit-Osada and Root ZX-Morita Corp.) ability in apical foramen localization using sodium hypoclorite as irrigating solution. 40 human monorooted teeth with immature apex were studied. 20 samples were measured by Apit and 20 by Root ZX; measurements were recorded when apical foramen was reached. Samples were fixed for stereomicroscope observation before and after apical 3 mm worn and prepared for SEM observation. Evaluations about each system's precision were made by calculating difference between foramen position determined by electronic localizer and its real anatomical position determined by a computed image analizing system linked to SEM. All measurements were included between a minimum value of -0.45 mm and a maximum value of 0.26 mm. Mann Whithney U test was performed to compare average values of the two sample groups but his was not meaningful (p = 0.18) showing that there is no valuable difference in accuracy between Apit and Root ZX. According to most researchers, who consider a +/- 0.5 mm error range clinically acceptable, and considering that in vitro measurements never exceded this limit value we conclude confirming both instruments' safety.

Dental Equipment↗
PubMed1994

A robotics-assisted procedure for large scale cystic fibrosis mutation analysis.

We describe a convenient, efficient, semiautomated protocol for assaying large numbers of DNA samples for over 20 mutations causing cystic fibrosis. The protocol uses the following: (1) a programmable robotic workstation to perform rapid pipetting and dot-blotting operations, (2) an allele-specific oligonucleotide hybridization in a single water bath without correcting for G+C content of oligonucleotides, and (3) a combinatorial system that allows direct determination of the genotype for more frequent mutations. We have used this system routinely for 16 months for carrier detection and for diagnosis of cystic fibrosis. The method can be readily applied to any combination of allele-specific oligonucleotide assays whether for multiple alleles at one locus or for a few alleles at multiple loci.

Base Sequence↗
PubMed1994

Establishment of a cell line from a hepatocellular carcinoma from a patient with hemochromatosis.

We describe the establishment and characterization of a novel hepatoma cell line. This cell line, designated RBHF-1, was established from a hepatocellular carcinoma of a 67-yr-old man with a history of genetic hemochromatosis. At this writing, the cells have been maintained in RPMI-1640 tissue-culture medium and fetal calf serum without any additional supplements for 30 mo. The cells form colonies on soft agar and are not tumorigenic in nude mice. The cell line is polymorphic and displays characteristics of mature hepatocytes by synthesizing albumin, alpha 2-macroglobulin, fibronectin and alpha-fetoprotein. Cytogenetic analysis shows multiple chromosomal aberrations, with a consistent deletion in the long arm and deletions or rearrangements in the short arm of chromosome 1. There is no evidence for hepatitis B or hepatitis C virus infection of the cell line. The cells contain no detectable intracellular iron after staining with Perls' stain. Unlike other hepatoma cell lines, there is no detectable binding of epidermal growth factor to RBHF-1 cells. This is the first cell line to be established from a patient with hemochromatosis, and it provides a potentially important model for the study of hepatocyte transformation in association with iron overload.

Aged↗
PubMed1994

Outpatient laparoscopic cholecystectomy.

Outpatient Laparoscopic Cholecystectomy was attempted in 98 patients selected from 266 patients presenting for elective cholecystectomy (37%). Two patients required admission following conversion to "open" Cholecystectomy, one patient was admitted for observation because of a technically difficult Laparoscopic Cholecystectomy and 16 patients were admitted because of refractory nausea and vomiting in the early post-operative period. Seventy-nine patients (81%) were able to be discharged home within 4 to 6 hours of surgery, with only one patient requiring readmission to hospital because of the onset of nausea and vomiting. There were no post-operative complications attributable to the outpatient experience. We believe this approach to elective gallbladder pathology can be safely accomplished in selected patients and will be increasingly utilized in the future.

Adult↗
PubMed1994

[The ultrastructural aspects of the carious lesion].

The aim of the present study was to analyse under SEM the ultrastructural alterations in tubular content and peri- and intertubular dentin in teeth subject to active carious lesions. The samples used were teeth with grade 2 active carious lesions without signs of abrasion, wear, erosion and conservative reconstruction. The coronal fragments obtained by fracture were fixated, dehydrated and metallized before SEM analysis. The study was performed by analysing samples of amelo-dentinal junctions towards the pulpo-dentinal edge. By correlating histopathological lesions to their topographical distribution and to the physiopathological mechanisms involved, it was possible to subdivide dentin underlying a carious lesion into three main zones: demineralisation zone, sclerosis zone, subsclerotic dentin zone. The individualization of these sectors was based on the identification of basic lesions linked to changes in tubular lumen and peri and intertubular dentin. The demineralisation zone was in fact characterised by: dentinal infection and reversal of normal tissue morphology in the outermost layers; the fibrous appearance of intertubular dentin and disappearance of peritubular dentin; modifications in the tubular content secondary to demineralisation, such as sheaths, hollow rods and intratubular crystals. The sclerosis zone was characterised by: fully occluded tubules, tubules fully occluded by rods, tubules partially occluded by hollow rods and by thickening of peritubular dentin. The third zone was the result of tissue-forming activity on the pulpodentinal edge in response to carious lesions and was represented by regular and irregular tertiary dentin. From an analysis of all data collected it is possible to hypothesize that changes in the demineralisation zone are the results of a passive tissue response exclusively linked to physicochemical mechanisms; whereas those in the sclerosis zone are due to the realisation of a lithogenic environment of multifactorial genesis at a intratubular level. The site in which there is the greatest probability of observing a cellular response is the subsclerotic dentinal zone.

Adolescent↗
PubMed1994

Synthesis and antihepatotoxic activity of silybin 11-O-phosphate.

Silybin 11-O-phosphate 3 was synthesized by selective phosphorylation of silybin with POCl3. The pharmacological activity of 3 was evaluated in the rat by using the praseodymium poisoning test. Preliminary results showed that the compound possesses antihepatotoxic activity, possibly with lower potency compared to the reference drug silybin hemisuccinate.

Alanine Transaminase↗