1603-2003: Four centuries of valves.
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Blood Vessel Prosthesis↗
Biomedical subjects
A Pieri
Publications and source records attributed to A Pieri.
Primary prevention of deep venous thrombosis and pulmonary embolism in acute spinal cord injured patients.
STUDY DESIGN: Prospective clinical trial. OBJECTIVES: To evaluate the efficacy of a specific protocol for prevention of thrombo-embolic disease occurring during the acute stage of spinal cord lesions, based on the simultaneous use of pharmacological plus mechanical procedures. SETTING: Regional Spinal Unit of Florence, Italy. INTRODUCTION: Deep venous thrombosis (DVT) is a dangerous pathology whose first clinical sign can be represented by unexpected pulmonary embolism (PE). Its incidence in acute spinal cord injured (SCI) patients is reported to range between 9% and 90%. Its prevention represents one of the major challenges for the clinicians involved in the care of such patients. METHOD: Two hundred and seventy-five SCI patients consecutively admitted to our Centre were investigated by colour doppler ultrasonography of lower limbs and pelvis on admission, after 30-45 days and whenever clinically requested. Subcutaneous Nadroparine, a low molecular weight heparin (LMWH), plus early mobilisation, permanently dressed gradient elastic stockings (PGES), and external sequential pneumatic compression (ESPC) of the lower limbs, applied during the first 30 days after injury, were given to all of them. Colour doppler ultrasonography (CDUS) complete investigations of the lower limbs and pelvis were performed on admission, after 30-45 days and whenever clinically requested. The patients were divided into two groups according to their time interval from injury to the admission to our Centre. RESULTS: The incidence of detected DVT was 2% in those patients (99) admitted early to our centre (within 72 h from the trauma), who immediately received our prophylactic protocol. No PE was reported. The other group of patients (176), all admitted between 8 and 28 days (mean 12 days) developed DVT in 26% of cases. None of these patients received ESPC before being admitted to our Centre. No patient had been admitted between 3 and 8 days interval time post injury. CONCLUSION: Early application of pharmacological plus mechanical treatment for DVT prevention produces a marked reduction in such complications. It also reduces the risks of morbidity and mortality in our patients, and, not least, reduces the hospitalization costs during the early period of rehabilitation.
Acute Disease↗
Interaction between acylphosphatase and SERCA in SH-SY5Y cells.
Ca2+ transport by sarco/endoplasmic reticulum, tightly coupled with the enzymatic activity of Ca2+ -dependent ATPase, controls the cell cycle through the regulation of genes operating in the critical G, to S checkpoint. Experimental studies demonstrated that acylphosphatase actively hydrolyses the phosphorylated intermediate of sarco/endoplasmic reticulum calcium ATPase (SERCA) and therefore enhances the activity of Ca2+ pump. In this study we found that SH-SY5Y neuroblastoma cell division was blocked by entry into a quiescent G0-like state by thapsigargin, a high specific SERCA inhibitor, highlighting the regulatory role of SERCA in cell cycle progression. Addition of physiological amounts of acylphosphatase to SY5Y membranes resulted in a significant increase in the rate of ATP hydrolysis of SERCA. In synchronized cells a concomitant variation of the level of acylphosphatase isoenzymes opposite to that of intracellular free calcium during the G1 and S phases occurs. Particularly, during G1 phase progression the isoenzymes content declined steadily and hit the lowest level after 6 h from G0 to G1 transition with a concomitant significant increase of calcium levels. No changes in free calcium and acylphosphatase levels upon thapsigargin inhibition were observed. Moreover, a specific binding between acylphosphatase and SERCA was demonstrated. No significant change in SERCA-2 expression was found. These findings suggest that the hydrolytic activity of acylphosphatase increase the turnover of the phosphoenzyme intermediate with the consequences of an enhanced efficiency of calcium transport across endoplasmic reticulum and a subsequent decrease in cytoplasmic calcium levels. A hypothesis about the modulation of SERCA activity by acylphosphatase during cell cycle in SY5Y cells in discussed.
Acid Anhydride Hydrolases↗
An in vivo model of hyperacute rejection: characterization and evaluation of the effect of transgenic human complement inhibitors.
Hyperacute rejection (HAR) occurring after transplantation within phylogenetically distant species is a severe reaction triggered by preexisting xenoreactive antibodies and complement activation, leading to the destruction of the donor organ. Expression of human complement inhibitors in transgenic pig organs prolongs the survival of xenograft in experimental models. Moreover, the extent of protection from hyperacute rejection is dependent on the level and site of expression of the transgenic molecules and, probably, on the combination of different molecules. In this regard a small animal model to test the efficacy of expression vectors and different human molecules could be very advantageous. A murine model developed in our laboratory was characterized by measurement of several parameters characteristic of HAR in the livers of control and transgenic mice expressing transgenic human DAF (CD55) or MCP (CD46) at the end of 2 h of perfusion with human plasma and after I day. The parameters studied were heamatological values of hepatic functions (GOT and GPT), induction of pro-inflammatory molecules and histopathological evaluation. Cytokines (IL-1alpha, IL-1beta, IL-6) induction and exposure of P-selectin on the endothelial cell surface, was only observed in control animals after 2 h of perfusion, as an early event. GOT and GPT values increase dramatically after 2 h perfusion and 1 day after the treatment according to the histopathological observation of liver damage. On the contrary, the livers of hDAF or hMCP transgenic mice, under the same treatment were significantly protected although the extent of this protection is dependent on the level of expression of transgenic human molecules.
Alanine Transaminase↗
Oxidative stress and calcium homeostasis in dystrophic skin fibroblasts.
Muscular dystrophy is a genetic disease that affects primarily skeletal muscle. The dystrophin absence has been related to the degeneration of muscle fibres. Indirect evidences suggest that oxidative stress may play a role in the pathogenesis of the disease, but the significance and precise extent of this contribution is poorly understood. In this paper we show that Becker Muscular Dystrophy (BMD) and Duchenne Muscular Dystrophy (DMD) skin fibroblasts are more susceptible to H2O2 treatment than are fibroblasts from unaffected persons. In particular, we found that, in growing DMD skin fibroblasts, the oxidative treatment resulted in significantly reduced growing capacity. We also investigated the concentrations of intracellular calcium during H2O2 treatment. The intracellular free calcium concentration increased by 22%, 35%, and 40% in unaffected, BMD, and DMD fibroblasts, respectively. However, the increase of the intracellular free calcium concentration is not related, as previously hypothesized, to a reduction of acylphosphatase concentrations, which seem to be unaffected by the H2O2 treatment, but rather to reduced enzyme activity.
Acid Anhydride Hydrolases↗
Utility of an integrated clinical, echocardiographic, and venous ultrasonographic approach for triage of patients with suspected pulmonary embolism.
The potential role of ultrasound techniques in diagnosing acute pulmonary embolism (PE) has been investigated in severe cases with hemodynamic compromise, but is still unclear for the whole clinical spectrum of patients with suspected PE. The aim of this study was to assess the utility of an integrated bedside evaluation for PE based on the combination of a clinical score, 2-dimensional echocardiography, and color venous duplex scanning. A group of 117 consecutive patients with suspected PE was assessed using a clinical likelihood score, echocardiography, and venous duplex scanning in order to obtain a preliminary diagnosis of PE, which was subsequently compared with the final diagnosis obtained by lung perfusion scintigraphy and angiography. A preliminary diagnosis of PE was made in 70 patients; a final diagnosis of PE was made in 63 patients, of which 56 had and 7 did not have a preliminary diagnosis of PE. The preliminary diagnosis therefore showed 89% sensitivity and 74% specificity, with a total accuracy of 82%. In patients with massive PE, sensitivity and negative predictive values of the preliminary diagnosis were 97% and 98%, respectively. Echocardiography was poorly sensitive (51%) but highly specific (87%) for PE. Thus, the integration of clinical likelihood, echocardiography, and venous duplex scanning provides a practical approach to patients with suspected PE, allows the rapid implementation of appropriate management strategies, and may reduce or postpone the need for further instrumental evaluation of more limited access.
Adult↗
Drosophila melanogaster acylphosphatase: a common ancestor for acylphosphatase isoenzymes of vertebrate species.
An open reading frame encoding a putative acylphosphatase was found in Drosophila melanogaster. The corresponding gene product shows 40% identity and 22 additional amino acid residues at the C-terminus as compared to muscle- and common-type human acylphosphatases. Moreover, all the residues involved in the catalytic mechanism of vertebrate enzymes are conserved in the D. melanogaster acylphosphatase. The D. melanogaster protein and a deletion mutant, similar in length to vertebrate acylphosphatases, were produced by cloning the corresponding cDNA in Escherichia coli. The wild-type enzyme is a protein with a well-established three-dimensional fold and a markedly reduced conformational stability as compared to vertebrate isoenzymes. The specific activity of the enzyme is significantly lower than that found in vertebrate enzymes though the substrate binding capability is basically unaltered. The deletion of 22 residues does not cause a significant change in k(cat), while affecting the apparent binding parameters. This work suggests that the genes encoding the vertebrate enzymes originate from an ancestor gene by duplication and subsequent evolution.
Acid Anhydride Hydrolases↗
Diagnosis of vertebrobasilar insufficiency: time to rethink established dogma?
As isolated symptoms, vertigo, dizziness and imbalance are not regarded by neurologists as reflections of transient ischemia in the vertebrobasilar circulation. The purpose of this retrospective study was to demonstrate that these symptoms can and do occur in isolation. To this end, we analyzed the symptoms, stroke risk factors and diagnostic algorithms in 27 patients with a diagnosis of transient vertebrobasilar ischemia. None of the 27 patients included in the review complained of any associated neurologic symptoms. Against the reference standard of brain imaging, the site of the pathologic lesion was defined in the brainstem/cerebellum with the Torok monothermal caloric test, with a sensitivity greater than 86%. Vestibular decruitment and hyperactive caloric responses were of particular diagnostic value. Thus, we recommend that the neurologic dogma with regard to brainstem cerebellar ischemia be rethought.
Adolescent↗
Alteration of free calcium levels and acylphosphatase muscular isoenzyme in cultured dystrophic skin fibroblasts.
Levels of free intracellular calcium have been measured on two cell lines of cultured human fibroblasts carrying the genetic lesions occurring in Duchenne and Becker dystrophies. Both cell lines elicited a markedly higher content of the cation (98 nM and 57 nM, respectively) than control fibroblasts (35 nM). Differences toward controls were statistically significant (p < 0.01). Dystrophic fibroblasts were also found to possess a significantly reduced amount by about 50% of muscular acylphosphatase isoenzyme as compared to normal cells. As acylphosphatase was demonstrated to be involved in the regulation of Ca2+-ATPase activity from different sources, a hypothesis was formulated that could explain the disruption of calcium homeostasis as an effect of the altered acylphosphatase activity.
Acid Anhydride Hydrolases↗
Alteration of intracellular free calcium and acylphosphatase levels in differentiating SH-SY5Y neuroblastoma cells.
Levels of acylphosphatase isoenzymes and free intracellular calcium have been investigated in cultured SH-SY5Y human neuroblastoma cells under stimulation with all-trans retinoic acid and phorbol-12-myristate-13-acetate. Under these conditions morphological and functional characteristics demonstrated the differentiation of SH-SY5Y cells towards neuronal phenotype. Retinoic acid treatment caused a progressive and synchronous increase of the organ common-type acylphosphatase and of free intracellular calcium but not of the muscle-type acylphosphatase. Phorbol-12-myristate-13-acetate treatment gave rise to a peak of the muscle-type acylphosphatase levels during the early differentiation stage whereas organ common-type isoenzyme and free calcium levels show a pattern similar to that observed in retinoic acid-treated cells. These evidences indicate that the two acylphosphatase isoenzymes play different roles in SH-SY5Y differentiation and that during this process the expression of organ common-type acylphosphatase increases in a synchronous way with intracellular free calcium concentration.
Acid Anhydride Hydrolases↗
Alteration of acylphosphatase levels in familial Alzheimer's disease fibroblasts with presenilin gene mutations.
Acylphosphatase (AcPase), an enzyme that modulates the activity of Ca(2+)-ATPase by hydrolysing its phosphorylated moiety, has been found to be significantly higher in cultured skin fibroblasts from donors affected by early onset familial Alzheimer's disease (EOFAD) with PS-1 and PS-2 gene mutations. Of the two known isoenzymes of acylphosphatase, only the erythrocyte one accounts for the total increase in activity. No relevant alteration was observed in phosphotyrosine phosphatase activity (PTPase), in Ca(2+)-ATPase and Na+, K(+)-ATPase activities of the same cells as compared to age-matched controls. This finding could suggest a possible explanation for the calcium-dependent biochemical alterations previously described in Alzheimer's disease fibroblasts.
Acid Anhydride Hydrolases↗
Crystallisation and preliminary X-ray analysis of the 'common-type' acylphosphatase.
Single crystals of a 'common-type' acylphosphatase from bovine testis have been grown. Crystals belong to space group C2 and have cell dimensions a = 64.6 A, b = 36.5 A, c = 45.2 A and beta = 104.8 and contain one monomer per asymmetric unit. The crystals diffract better than 2.0 A resolution and are well suited for an X-ray structure determination.
Acid Anhydride Hydrolases↗
Setting up and statistical evaluation of a new haemoglobin assay.
A new method for the determination of haemoglobin concentration in human whole blood has been devised. The assay takes advantage of the lysis of erythrocytes that occurs when blood penetrates the pores of a microporous membrane by a strong capillary effect. The released haemoglobin reacts with the reagents previously dried on the membrane, diffuses through the pores of the membrane and produces a uniform coloured spot whose reflectance at 556 nm can be evaluated at the side to that of application of the sample. In the experimental conditions used by authors, a linear relationship was obtained when the reciprocal reflectance was plotted against the haemoglobin concentration. Data obtained by the reflectometric method were compared with reference values on the same samples from centralized laboratories. Statistical analysis gave a correlation coefficient of 0.985 and only 4% of all haemoglobin determinations were outside the 95% confidence interval. No interference was observed by haematocrit, erythrocyte count, mean corpuscular volume or mean corpuscular haemoglobin concentration and leukocyte count. This method proved to be useful for rapid, accurate and precise assay of total haemoglobin on both capillary and venous blood.
Blood Cell Count↗
Expression of human acylphosphatase in Escherichia coli affects intracellular calcium levels.
In vitro experiments demonstrated the ability of acylphosphatase to hydrolyze the phosphorylated intermediate that is formed during the activity of Na+, K(+)- and Ca(2+)-ATPases of mammalian cells membranes. In order to investigate the effect of this enzyme on intracellular cation levels, a synthetic gene for human muscle acylphosphatase has been expressed in E. coli strains BL21 and JM101. Intracellular total steady-state calcium concentration, as measured by isotopic exchange, was significantly higher in transformed cells as compared to controls and the rising was dependent on the level of acylphosphatase expression. Accordingly also free intracellular calcium concentration, as measured by Fura-2 fluorescence, increased in transformed cells. On the other hand, phosphate levels were not affected by the expression of acylphosphatase, while sodium and rubidium levels increase in transformed cells. Intracellular pH resulted to be slightly affected by the expression of acylphosphatase, cytoplasm of transformed JM101 bacteria being more alkaline (pH 7.45) as compared to control cells (pH 7.40). On the basis of these results, it can be suggested that acylphosphatase acts in vivo by regulating the cation transport in E. coli.
Acid Anhydride Hydrolases↗
Rebound caloric nystagmus.
Rebound caloric nystagmus (RCN), a distinctly different phenomenon from secondary phase nystagmus (SPN), was serendipitously discovered during the course of routine neurotological evaluations. RCN occurred when the horizontal semicircular canal was brought into a truly horizontal plane after the primary phase nystagmus (PPN) had ended. The maximum slow-phase velocities (SPVMax) of both PPN and RCN were almost identical. The pathological lesion was an Arnold-Chiari malformation (ACM). Two other patients with posterior fossa lesions also showed RCN. To determine if RCN is an unrecognized normal phenomenon, 11 healthy subjects were tested. The average SPV of RCN in normals was 0.7 degrees per second. Such a small value of RCN is probably of no significance. It therefore appears that RCN is a sign of posterior fossa neuroaxial lesions.
Adult↗
The Italian Pain Questionnaire.
In order to overcome the cross-cultural semantic barriers related to the literal translation of the McGill Pain Questionnaire (MPQ) in non-English speaking areas, an Italian Pain Questionnaire (IPQ) has been developed, based on the 3 factorial structures proposed by Melzack and Torgerson: sensory, affective and evaluative. A group of 30 normal subjects (15 doctors and 15 university students) was used to define 5 anchor words of the intensity verbal scale by means of a visual analogue scale, and a 5-point Present Pain Intensity (PPI) verbal scale was derived. For the semantic key, a first group of 80 subjects (30 university students and patients, respectively, and 20 doctors) was asked to sort out appropriate pain descriptors from 203 pain-related words with the help of clinical literature and Italian dictionaries. Subsequently, a second group of 80 subjects (of identical structural composition) was asked to allocate the 56 words previously chosen on the basis of word frequencies (at least 45%) to the most appropriate category in the Italianized MPQ. Testees were then asked to assign an intensity value to each word, using a VAS scale. The final pain vocabulary was formed from those words, which reflected a statistically significant intensity change (P less than 0.05) within each group. The IPQ comprises 42 pain descriptors, distributed into 3 major classes (sensory, affective and evaluative) and 16 subclasses. It represents the most parsimonious, meaningful and idiomatic set of Italian pain descriptors, providing quantitative information that can be treated statistically, yet preserving a close structural parallel with the MPQ.
Adolescent↗
[Multiparameter evaluation of tricuspid insufficiency using two-dimensional echocardiography, Doppler and contrast echocardiography].
The evaluation of the presence and severity of tricuspid insufficiency is still difficult even if many criteria of grading are available for different techniques. In this study the data obtained from Doppler mapping of the right atrium, from the analysis of the hepatic vein flow and from the contrast echocardiography of the inferior vena cava in 56 patients with mitral or mitral-aortic valvulopathy and with clinically suspected tricuspid insufficiency were submitted to the cluster analysis. This analysis was used to redistribute the study population according to the following parameters: diameter of the inferior vena cava, maximal systolic and diastolic flow of the hepatic veins, the length of regurgitant jet in right atrium and the duration of contrast in vena cava. The aim was to identify the variability range of each degree of severity. None of the analyzed parameters "per se" identifies the regurgitation severity because there is a large variability in the intermediate degrees. The cluster analysis shows a definite pattern of parameters for each cluster (1 = no significant regurgitation, 2 = mild, 3 = moderate, 4 = severe insufficiency).(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Chronic total renal artery occlusion: a diagnostic challenge.
Chronic renal artery occlusion must be suspected whenever a moderate hypertensive patient over 50 years of age presents increase of blood pressure refractory to treatment, sometimes causing heart failure or stroke. This suspicion is reinforced by the presence of renal insufficiency and of anatomical and/or functional lateralization of renal damage at intravenous pyelography.
Adult↗