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Biomedical subjects

A Rinaldi

Publications and source records attributed to A Rinaldi.

At least 55 records · Page 3Linked to original sources
PubMed1996

[Detection of microbubbles formed in the blood/CO2 interphase during decompression in barometric conditions similar to laparoscopy].

HYPOTHESIS AND OBJECTIVES: Intraperitoneal insufflation (IPI) with CO2 during laparoscopic surgery establishes a pressure gradient that determines the passage of gas from the peritoneal cavity to the blood and surrounding tissues. The transport and clearance of CO2 are assured by proper sweeping when regional blood flow is adequate in volume and distribution. But if IPI hyperpressure surpasses regional venous capillary pressure (10 to 15 mmHg) and there is no cardio-circulatory adaptation to the phenomenon, CO2 clearance may be compromised. Under these conditions, the expected post-insufflation increase in PetCO2 will not take place. Bearing in mind the physical characteristics of CO2, retention of this gas in the intraperitoneal cavity produces blood and tissue saturation under a higher-than-atmospheric pressure, after a certain period of time in contact. Rapid intraperitoneal decompression after laparoscopic surgery carries with it the risk of microbubble formation due to release of CO2 that had been dissolved under hyperbaric conditions. MATERIAL AND METHODS: To test this hypothesis, the barometric conditions of laparoscopy were reproduced inside an observation capsule containing blood and CO2. RESULTS: Magnification revealed that after decompression bubbles formed in the blood/CO2 interphase. The images were recorded on magnetic videotape. Thirty minutes after decompression, the bubbles could still be seen, even after the interphase was swept with a current of air. DISCUSSION: Rapid intraperitoneal decompression after laparoscopy can generate the formation of microbubbles which, if not eliminated, will give rise to local ischemic manifestations. This same decompression, correcting the local circulatory alterations and activating the CO2 transport that had been compromised, could introduce gas bubbles into the blood stream such as are responsible for delayed gaseous microembolism. The simultaneous observation of changes in PetCO2 (stability or post-insufflation decreases) and hemodynamic parameters during laparoscopy, would allow evolving anomalies to be detected early and therapeutic action to be taken to prevent the formation of microbubbles.

Carbon Dioxide↗
PubMed1995

X-linked ichthyosis without STS deficiency: clinical, genetical, and molecular studies.

We report on a Sardinian pedigree with congenital ichthyosis associated with normal levels of steroid sulfatase and a normal molecular pattern, as detectable with a cDNA probe for the steroid sulfatase (STS) gene. Though the pattern of transmission of the disease is consistent with X-linked recessive inheritance, this form of ichthyosis was found to segregate independently of genetic polymorphisms detected by probes of the region Xp22.3, where the STS locus has been mapped. The search for close genetic linkages with other polymorphic markers scattered along the entire X chromosome has so far been fruitless. For the time being, the main conclusion derived from these data is that STS deficiency is not a sine qua non for X-linked ichthyosis which may also result from a mutational event at an X-chromosomal site genetically unlinked to the STS locus.

Arylsulfatases↗
PubMed1995

Autoxidation of 4-methylcatechol: a model for the study of the biosynthesis of copper amine oxidases quinonoid cofactor.

The autoxidation of 4-methylcatechol under quasi-physiological conditions, leading to 2-hydroxy-5-methyl-1,4-benzoquinone, was investigated. The effects of pH and metal ions were examined. An electrophilic attack of dioxygen to the 4-methylcatechol monoanion to form a transient peroxo species is proposed. It was concluded that such a non-enzymic conversion is likely for this model compound and for its physiological counterpart, a specific tyrosyl residue incorporated in the protein chain at the active site of copper amine oxidases.

Amine Oxidase (Copper-Containing)↗
PubMed1995

A hydroxyquinone with amine oxidase activity: preparation and properties.

The preparation and some properties of a hydroxyquinone showing an amine oxidase-like activity are described. The compound, 2-hydroxy-5-methyl-1,4-benzoquinone, oxidizes a wide range of primary amines, both benzylic and non-benzylic, at the expenses of molecular oxygen in the presence of Cu2+ ions, and reacts with hydrazine derivatives leading to stable, inactive adducts. This behaviour is similar to that of 2,4,5-trihydroxyphenylalanine quinone-containing amine oxidases and therefore the present compound could be a useful model to understand the reaction mechanism of those enzymes.

Amine Oxidase (Copper-Containing)↗
PubMed1995

Effect of NAD(P)H:quinone oxidoreductase on tyrosinase-mediated oxidation of opioid neuropeptides Leu-enkephalin and Met-enkephalin.

In vitro experiments are reported showing that NAD(P)H:(quinone acceptor) oxidoreductase (QR), purified from Glycine max seedlings, reduces Leu- and Met-enkephalin-tyrosinase oxidation products, in the presence of NADH or NADPH. QR was not capable to catalyze the reduction of N-acetyl-dopaquinone formed by the cation of mushroom tyrosinase on N-acetyl-L-tyrosine, while it was able to reduce dopachrome. The results support the hypothesis that QR can inhibit the formation of melanin-like compounds, as catalyzed by the action of tyrosinase on Leu-enkephalin and Met-enkephalin. It is proposed that, in the presence of NAD(P)H as the electron donor, the inhibition occurs by the specific conversion of the dopachrome-derivative into the reduced precursor, leucodopachrome-derivative.

Enkephalin, Leucine↗
PubMed1994

Automated percutaneous discectomy in herniated lumbar discs treatment: experience after the first 200 cases.

Two hundred patients presenting lumbo-sacral radicular pain were treated with automated percutaneous discectomy and were divided into two groups, on the ground of their symptomatology: group A included those patients that, otherwise, would undergo conservative therapy, because of their moderate pain; group B gathered patients whose severe pain needed undelayed surgery. The success rate that we reported in group A was 85%, while, in group B, it was 64%. Recurrences needing open surgery occurred in 15% of group B. Although characterized by delayed recovery, this technique seems to have good results even in so called surgical patients, in comparison with open surgery.

Adolescent↗
PubMed1994

Photometric estimation of cadaverine oxidation by copper amine oxidase.

A simple method for the photometric estimation of 1-piperideine, produced by the action of copper amino oxidases on cadaverine, is described. A discussion on the formation of 1-piperideine from lysine in acidic medium is also reported, together with some observations on the nature of acid 1-piperideine-ninhydrin condensation product.

Amine Oxidase (Copper-Containing)↗
PubMed1993

Childhood precursors of affective vs. social deficits in adolescents at risk for schizophrenia.

Childhood attentional and neuromotor precursors of social competence and affective deficits in adolescents at risk for schizophrenia, adolescents at risk for affective disorder, and matched comparison adolescents were examined. The subjects were offspring of parents with schizophrenia or affective disorder and of normal parents matched on age, sex, and socioeconomic status from the New York High-Risk Project (Sample B). On the basis of interviews conducted when the subjects were children and adolescents, social competence was rated from child reports and parent reports, affective deficits were assessed by affective flattening ratings, and smiling was assessed by counting broad smiles. Adolescents at risk for schizophrenia had significantly greater social and affective deficits than adolescents at risk for affective disorder and comparison adolescents. In subjects at risk for schizophrenia, childhood neuromotor dysfunction predicted adolescent affective flattening, and childhood attentional dysfunction predicted adolescent social deficits. The results suggest that affective and social deficits in schizophrenia have different childhood precursors.

Adolescent↗
PubMed1992

[Transesophageal echo-Doppler in children: the importance of the exact measurement of the aortic diameter and its variations over time for estimating the aortic output].

The purpose of the study was to evaluate a new non invasive system of hemodynamic monitoring. The aortic systolic, diastolic and mean diameter have been measured with eco-TM and the aortic blood flow with pulsed Doppler, in order to obtain the aortic output. The aortic systolic diameter and the derived aortic output were then compared to the corresponding values obtained with CT. Ten healthy children were asked to be explored with CT under general anaesthesia and an oesophageal probe was positioned. The mean aortic diameter value was 7.18 +/- 0.91 mm. The systolic and diastolic aortic diameter was 7.87 +/- 0.91 mm and 6.65 +/- 1 mm respectively. The aortic systolic diameter measured with CT was 8.2 +/- 0.92 mm. Correlation analysis with aortic systolic diameter with eco TM as the dependent variable and aortic systolic diameter with CT as the independent variable revealed a highly significant correlation (r = 0.95, coefficient of determination 0.90). The mean percentage difference between systolic and diastolic diameter measured with TM eco scan was 15% with maximum variation 22% and minimum of 10% (p less than 0.003). The aortic blood flow calculated from the systolic aortic diameter was 29% higher than that obtained from diastolic aortic diameter. This would suggest that the correct measurement of the aortic diameter has to be considered in the final evaluation of aortic output especially in children in whom the elasticity of the aortic wall represents a major factor in determining fluctuations of aortic diameter.

Aorta↗
PubMed1991

Description of a home care service for cancer patients through quantitative indexes of evaluation.

Home care (HC) was created and developed in Romagna, as in other parts of Italy, thanks to the endeavor of a private institution, the "Istituto Oncologico Romagnolo". The care is gratis to advanced cancer patients and is based on the palliative philosophy of treatment of the symptoms and the person within the framework of continuity of care permitted by the oncologic approach. To evaluate the intensiveness of the operation in terms of medical and nursing care by means of quantitative indexes, we examined several variables which emerged from a retrospective analysis of our case study. The average duration of care of the 484 patients in the program as of 31 December 1990 was 84.1 days. Four hundred and twenty-three patients of the 484 (87.1% of the total) have died and 61 were still in the HC program at the time of this analysis. The 61 living patients were thus excluded from the descriptive analysis to give greater homogeneity to the study group. The average duration of care for the 423 decreased patients was 68.1 days. Out of a total of 28,759 days of HC for the entire group, the patients actually spent 23,534 days (81.8%) at home. The average duration of hospitalization was 13.5 days, and in 33.2% of the cases it was motivated by psychologic and family causes. The place of death was the home in 44.3% of the cases. A medical or nursing visit was made at the home every 1.4 days, and the average number of visits per patient was 39.0. Although none of the indexes alone can give overall indications of the intensiveness of a HC service, they may constitute a working proposal for the definition of the most objective criteria possible for the quantitative evaluation of such experiences.

Adolescent↗
PubMed1991

Premutation for the Martin-Bell syndrome analyzed in a large pedigree segregating also for G6PD-deficiency. I: A working hypothesis on the nature of the FRAX-mutations.

A large Sardinian family including 13 Martin-Bell syndrome (MBS) patients, several instances of normal transmitting males or females, and the G6PD-Mediterranean mutant segregating in some of its branches, has been thoroughly investigated with the hope of gaining further insight on the nature of the FRAX-mutation. All the MBS patients and the 15 obligate heterozygous women present in the pedigree could be traced back through their X-chromosome lineage to the same ancestress, who must have been heterozygous for a silent premutation at the FRAX-locus. This premutation appears to have turned into a true FRAX-mutation at least 9 times during the gametogenesis of the ancestress' X-related descendants of whom four are males. This finding alone suggests that the transition from the FRAX premutation to the true mutation can be the result of intra- as well as interchromosomal events. This conclusion is supported by the additional observation that the genetic phase between the FRAX and the G6PD loci remained unaltered when the transition occurred in a repulsion double heterozygote for the premutation and the G6PD-Mediterranean mutant. The data described are compatible with the hypothesis that MBS patients and normal transmitting males are, respectively, hemizygous for deletion or duplication products generated by aberrant recombination events at a highly recombinogenic site of the region Xq27-Xqter. The overall message stemming from this report is that no firm conclusion can be drawn on the genetic linkage between the FRAX-locus and other markers of this region until the nature of the FRAX-mutations and the mechanism of their occurrence are fully understood.

Adult↗
PubMed1991

DNA methylase from Pisum sativum.

DNA methylase activity was detected in nuclei from pea shoots. The enzyme can only be extracted by low-salt treatment if the nuclei are pretreated with micrococcal nuclease. Only a single enzyme was detected, and it was purified to a specific activity of 1620 units/mg of protein. It has an Mr of 160,000 on gel filtration and SDS/PAGE. Pea DNA methylase methylates cytosine in all four dinucleotides, and this is interpreted to show that it acts on CNG trinucleotides. Although it shows a strong preference for hemi-methylated double-stranded DNA, it is also capable of methylation de novo. Homologous DNA is the best natural substrate. In vitro the enzyme interacts with DNA to form a salt-resistant complex with DNA that is stable for at least 4 h.

Base Sequence↗
PubMed1991

Olive milling wastewater as a medium for growth of four Pleurotus species.

Four species of Pleurotus were adapted to grow on olive milling wastewater, and in certain conditions produced high yield of fruit bodies. Some biochemical transformations were observed in the olive milling wastewater owing to the growth of Pleurotus. In particular, the fungi actively excreted large amounts of laccase in the medium, and at the same time the concentration of phenolics and other toxic compounds significantly decreased, as revealed by HPLC analysis and toxicity tests on standard cultures of human cell lines.

Culture Media↗
PubMed1991

Microassay for DNA methyltransferase.

A microassay for DNA methylase is described which can detect activity in as few as 50 tissue culture cells. The cells are lysed and incubated for 2 h at 37 degrees C with 3 microCi high specific activity [3H]AdoMet and 0.5 microgram poly[d(I-C).d(I-C)] in a volume of 23 microliters. Ribonuclease is present during the assay and the product DNA is isolated by phenol extraction after protease digestion.

DNA Modification Methylases↗
PubMed1991

Social competence and positive and negative symptoms: a longitudinal study of children and adolescents at risk for schizophrenia and affective disorder.

OBJECTIVE: The authors longitudinally examined social competence and positive and negative symptoms in children at risk for schizophrenia, children at risk for affective disorder, and matched normal subjects. METHOD: The subjects were offspring of parents with schizophrenia or affective disorder and normal comparison subjects matched on age, sex, and socioeconomic status. Ratings of social competence (Premorbid Adjustment Scale), affective flattening and poverty of speech (Scale for the Assessment of Negative Symptoms), and positive formal thought disorder (Scale for the Assessment of Positive Symptoms) were based on videotaped psychiatric interviews conducted in childhood (N = 144), early adolescence (N = 127), and adolescence (N = 106). RESULTS: In childhood, there were no significant group differences. In early adolescence, the subjects at risk for schizophrenia had poorer social competence than those at risk for affective disorder and the normal subjects. In early adolescence, the subjects at risk for schizophrenia also had greater positive thought disorder than those at risk for affective disorder but did not differ significantly from the normal subjects; there were no differences in negative symptoms. In adolescence, the subjects at risk for schizophrenia had poorer social competence and greater positive and negative symptoms than the adolescents at risk for affective disorder and the normal subjects. CONCLUSIONS: During early adolescence and adolescence, poor social competence may be more characteristic of children at risk for schizophrenia than those at risk for affective disorder. Higher levels of positive and negative symptoms may also be specific to subjects at risk for schizophrenia, but only during adolescence.

Adolescent↗
PubMed1991

Decrease in DNA methylase activity during preimplantation development in the mouse.

During early mouse development, there are large-scale changes in DNA methylation. These changes may be due to the availability or stability of the enzyme, DNA methyltransferase (methylase), which is responsible for maintenance of DNA methylation. A microassay for methylase activity in preimplantation embryos shows that the level of maternally inherited enzyme is extremely high in the egg and that this activity is stable for the first three cleavage divisions. However, from the 8-cell to the blastocyst stage, there is a marked and absolute decrease in enzyme activity.

Animals↗