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Biomedical subjects

R Lombardi

Publications and source records attributed to R Lombardi.

At least 19 recordsLinked to original sources
PubMed2006

Fungal contamination in hospital environments.

OBJECTIVES: To assess the degree of fungal contamination in hospital environments and to evaluate the ability of air conditioning systems to reduce such contamination. METHODS: We monitored airborne microbial concentrations in various environments in 10 hospitals equipped with air conditioning. Sampling was performed with a portable Surface Air System impactor with replicate organism detection and counting plates containing a fungus-selective medium. The total fungal concentration was determined 72-120 hours after sampling. The genera most involved in infection were identified by macroscopic and microscopic observation. RESULTS: The mean concentration of airborne fungi in the set of environments examined was 19 +/- 19 colony-forming units (cfu) per cubic meter. Analysis of the fungal concentration in the different types of environments revealed different levels of contamination: the lowest mean values (12 +/- 14 cfu/m(3)) were recorded in operating theaters, and the highest (45 +/- 37 cfu/m(3)) were recorded in kitchens. Analyses revealed statistically significant differences between median values for the various environments. The fungal genus most commonly encountered was Penicillium, which, in kitchens, displayed the highest mean airborne concentration (8 +/- 2.4 cfu/m(3)). The percentage (35%) of Aspergillus documented in the wards was higher than that in any of the other environments monitored. CONCLUSIONS: The fungal concentrations recorded in the present study are comparable to those recorded in other studies conducted in hospital environments and are considerably lower than those seen in other indoor environments that are not air conditioned. These findings demonstrate the effectiveness of air-handling systems in reducing fungal contamination.

Air Conditioning↗
PubMed2004

Reducing the risk of intraoperative neurological complications during carotid endarterectomy with early distal control of the internal carotid artery.

AIM OF THE STUDY: To assess the feasibility and effectiveness of a modified surgical technique with early clamping of the distal internal carotid artery (ICA) during carotid endarterectomy in a single centre experience. STUDY DESIGN: Retrospective study, teaching hospital. MATERIAL AND METHODS: Between 1996 and 2002, 2235 CEAs were performed. Until April 1999, the intra-operative strategy consisted of standard isolation and dissection of the carotid bifurcation preliminary to ICA clamping (group 1; 1090 interventions). Starting from May 1999, we performed early isolation and clamping of the distal ICA, followed by dissection of the carotid bifurcation and clamping of the external and common carotid artery (group 2; 1145 interventions). RESULTS: The modified technique was feasible in all the patients of group 2. In group 2 there was a significantly lower incidence of neurological deficit on waking than in group 1 (0.4% and 1.8%, respectively; p=0.02). CONCLUSIONS: Early distal control of the internal carotid artery during CEA is feasible and could contribute to reducing intra-operative neurological events.

Carotid Artery, Internal↗
PubMed2003

Axonal swellings predict the degeneration of epidermal nerve fibers in painful neuropathies.

OBJECTIVE: To correlate the density of swellings in intraepidermal nerve fibers (IENF) with the longitudinal measurement of the epidermal innervation density in patients with painful neuropathy and to assess the predictive value of IENF swelling to progression of neuropathy. METHODS: Fifteen patients with persistent pain in the feet underwent neurologic examination, nerve conduction studies, quantitative sensory examination, and skin biopsies at proximal thigh and distal leg. In all patients and in 15 healthy subjects, IENF density and swelling ratio (no. swellings/no. IENF) were quantified at distal leg. Follow-up study, including IENF density and swelling ratio quantification, was performed a mean of 19.2 months later. Double staining confocal microscope studies using anti-human protein-gene-product 9.5, anti-tubule, anti-neurofilament, and anti-synaptophysin antibodies were performed to assess specific accumulation within swellings. Ultrastructural investigation of IENF was also carried out. RESULTS: Patients with neuropathy had lower density of IENF and higher swelling ratio than healthy subjects (p < 0.01) at distal leg. At follow-up, patients showed a parallel decrease in both IENF density (p = 0.02) and swelling ratio (p = 0.002). However, swelling ratio remained higher (p = 0.03) than in controls. Progression of neuropathy was confirmed by the decay in sural nerve sensory nerve action potential amplitude. Double immunostaining studies suggest accumulation of tubules and ubiquitin-associated proteins within swellings. Swollen and vacuolated IENF were identified in patients with neuropathy by conventional and immuno-electron microscopy. CONCLUSIONS: Increased swelling ratio predicted the decrease in IENF density in patients with painful neuropathy. Its quantification could support earlier diagnosis of sensory axonopathy.

Adult↗
PubMed2002

Detection and potential indicators of the presence of hepatitis C virus on surfaces in hospital settings.

AIMS: The risk of hepatitis C virus infection in hospital environments can be assessed not only by studying epidemiological data and work practices, but also by the detection of these viruses (or indicators thereof) in health-care settings, on instruments etc. METHODS: Since standardized techniques specific to this end do not exist, this study was undertaken to apply methods currently used on clinical samples to the assessment of environmental HCV risk, either through direct detection of the virus (RT-PCR), or by probing for haemoglobin as a potential indicator of blood contamination. The tested techniques were applied in a trial environmental monitoring programme undertaken in various hospital laboratories and clinics, during which total bacterial count determinations were performed in parallel with haemoglobin and hepatitis C virus detection. SIGNIFICANCE AND IMPACT OF THE STUDY: The data indicate that the applied methods are of value in detecting low levels of contamination in a hospital environment.

Environmental Monitoring↗
PubMed2002

Aetiology and pathogenesis of hypertrophic cardiomyopathy.

UNLABELLED: The term hypertrophic cardiomyopathy is used to describe an autosomal dominant cardiac disorder, characterized by myocyte hypertrophy and disarray, interstitial fibrosis and small vessel disease, with or without macroscopic hypertrophy. More than 100 mutations in ten genes, all encoding sarcomeric proteins, have been identified as responsible for this disease. Mutations in the genes for beta-myosin heavy chain, myosin binding protein-C, and cardiac troponin T are the most common. Other genes involved are alpha-tropomyosin, cardiac troponin-I, essential and regulatory light chains, alpha-cardiac actin, titin, and alpha-myosin heavy chain. Some mutations are more frequently associated with a given phenotype, but no particular phenotype is mutation specific; in fact, some mutations exhibit highly variable clinical, electrocardiographic and echocardiographic manifestations. This variability in the phenotypic manifestations is probably due to the influence of environmental factors and/or modifier genes. While the aetiology of hypertrophic cardiomyopathy has been extensively elucidated, its pathogenesis is not completely understood. Mutated proteins are incorporated in the sarcomere and impair myocyte contractility. This probably triggers the compensatory local release of trophic factors, which influence the development of the typical anatomical features of the disease, with a pathway similar to that observed in secondary, pressure overload hypertrophy. CONCLUSIONS: The various pathological cardiac changes seen in hypertrophic cardiomyopathy are probably due to a compensatory response to impaired myocyte function resulting from mutations in the genes encoding sarcomeric proteins.

Cardiomyopathy, Hypertrophic↗
PubMed2001

Sphingoid base signaling via Pkh kinases is required for endocytosis in yeast.

In yeast, sphingoid base synthesis is required for the internalization step of endocytosis and organization of the actin cytoskeleton. We show that overexpression of either one of the two kinases Pkh1p or Pkh2p, that are homologous to mammalian 3-phosphoinositide-dependent kinase-1 (PDK1), can specifically suppress the sphingoid base synthesis requirement for endocytosis. Pkh1p and Pkh2p have an overlapping function because only a mutant with impaired function of both kinases is defective for endocytosis. Pkh1/2p kinases are activated in vitro by nanomolar concentrations of sphingoid base. These results suggest that Pkh1/2p kinases are part of a sphingoid base-mediated signaling pathway that is required for the internalization step of endocytosis. The Pkc1p kinase that is phosphorylated by Pkh1/2p kinases and plays a role in endocytosis was identified as one of the downstream effectors of this signaling cascade.

3-Phosphoinositide-Dependent Protein Kinases↗
PubMed2001

Low plasma levels of vitamin B(6) are independently associated with a heightened risk of deep-vein thrombosis.

BACKGROUND: Elevated plasma levels of total homocysteine (tHcy) before and after an oral methionine load (PML) are associated with an elevated risk of deep-vein thrombosis (DVT). We investigated whether plasma levels of B vitamins that are involved in Hcy metabolism are associated with an elevated risk of DVT. METHODS AND RESULTS: We compared 397 cases with previous DVT with 585 matched healthy controls. The plasma levels of folate, vitamin B(12), vitamin B(6,), and fasting and PML tHcy were measured. The ORs for DVT associated with high (>95th percentile) fasting levels and PML increases of tHcy were 2.1 (95% CI, 1.2 to 3.4) and 2.4 (95% CI, 1.5 to 3.9) after adjustment for established risk factors for DVT. Fasting plasma levels and PML increases in tHcy correlated negatively with vitamin levels. The crude OR for folate levels in the lowest quartile compared with the highest was 1.5 (95% CI, 1.1 to 2.1), and that for B(6) levels in the lowest and second quartiles compared with the highest was 1.5 (95% CI, 1.0 to 2.1). However, after adjustment for established risk factors and fasting and PML tHcy, the ORs for B(6) levels in the lowest and second quartiles only remained statistically significant (lowest quartile: OR, 1.8; 95% CI, 1.2 to 2.8; second quartile, OR, 1.9; 95% CI, 1.3 to 2.9). CONCLUSIONS: High fasting and PML tHcy and low vitamin B(6) plasma levels are associated with an elevated risk for DVT independently of established risk factors for DVT. The association of low vitamin B(6) levels with the risk for DVT is independent of fasting and PML tHcy levels.

Adolescent↗
PubMed2001

Epidermal nerve fiber density in sensory ganglionopathies: clinical and neurophysiologic correlations.

We assessed the involvement of somatic unmyelinated fibers in sensory ganglionopathies by skin biopsy and quantitative sensory testing (QST). Sixteen patients with ganglionopathy, 16 with axonal neuropathy, and 15 normal controls underwent skin biopsy at the proximal thigh and the distal leg. Intraepidermal nerve fibers (IENF) were immunostained by antiprotein gene product 9.5, and their linear density was quantified under light microscopy. Confocal microscopy studies with double staining of nerve fibers and basement membrane were also performed. Healthy subjects and neuropathy patients showed the typical proximodistal gradient of IENF density; in neuropathies, values were significantly lower at the distal site of the leg, confirming the length-dependent loss of cutaneous innervation. Conversely, ganglionopathy patients with hyperalgesic symptoms did not show any change of IENF density between the proximal thigh and the distal leg. The distinct pattern of epidermal denervation seen in sensory ganglionopathy reflected the degeneration of somatic unmyelinated fibers in a fashion that was not length-dependent, which was consistent with both clinical and neurophysiologic observations and supported the diagnosis.

Biopsy↗
PubMed2001

Flow Rate Profiler: an instrument to measure blood velocity profiles.

In this paper we present Flow Rate Profiler (FRP), an instrument for measuring the blood velocity by means of ultrasound-based techniques. The velocity is directly related to the shear rate, which is in turn proportional to the shear stress, a parameter expressing the pressure exerted by the blood on the vessel walls. The knowledge of this value is important in medicine to establish the state of the vessels, directly related to vascular diseases. FRP provides a non-invasive measure of the blood velocity by exploiting the red corpuscles property of diffusing ultrasound waves: in practice blood velocity is determined by a cross-correlation technique, which analyses the time shift between correlated subsequent echo waves, instead of frequency shift characteristic of the Doppler technique. The acquired data are then processed on a personal computer by means of mathematical techniques based on the evaluation of the correlation function, giving a reconstructed velocity profile and showing a good adherence with experimental data, since the average error is nearly the 10%. The reconstructed profile is displayed to the operator, who can follow the vessel status in real time. A few comparisons between the reconstructed and the experimental profiles are also presented, together with a study on a small set of patients suffering from artery hypertension.

Blood Flow Velocity↗
PubMed2001

Multicenter study of homocysteine measurement--performance characteristics of different methods, influence of standards on interlaboratory agreement of results.

After the demonstration that moderate hyperhomocysteinemia is associated with thrombosis, many hematological labs are becoming interested in total homocysteine (tHcy) measurement. This prompted us to organize a collaborative study to investigate the performance of methods used in this setting and to assess the between-lab comparability of results. Two pairs of pooled plasma (A1-A2 and B1-B2) were prepared at the coordinating Center. tHcy levels were normal in A1-A2 and moderately high in B1-B2. Within each pair tHcy levels were similar but not identical. Aliquots were taken from each pool to prepare sets of 100 samples (coded from 1 to 100). Each set consisted of 25 replicates for each pool. Samples were frozen and shipped in dry ice to 16 labs with a common frozen aqueous standard. Labs were asked to measure (in blind) tHcy with their methods and standards. Results were sent to the coordinating Center both as raw readings and as tHcy levels. The following methods were used: High Pressure Liquid Chromatography (HPLC) in 12 labs (home-made in 10 and commercial in 2); Enzyme Immuno Assays (EIA) in 2; Fluorescence Polarization Immunoassay (FPIA) in 2 and Capillary Electrophoresis (CE) in one. Results for paired pools (A1-A2 and B1-B2) were analyzed by the Student t test to assess for the ability to discriminate between similar but not identical tHcy levels. Results for each pool were used to assess within-lab reproducibility and between-lab comparability. Within-lab reproducibility expressed as median CV ranged from 12.6 to 13.9% (home-made HPLC); from 9.2 to 11.4% (commercial HPLC); from 21.8 to 24.2% (EIA); from 2.7 to 3.3% (FPIA) and from 11.2 to 22.0% (CE). All labs, except one using CE and 2 using home-made HPLC, were able to discriminate between similar tHcy levels in the normal range (pools A1-A2). Ten labs (4 using home-made HPLC, 2 commercial HPLC, 2 FPIA, one EIA and one CE) were able to discriminate between similar moderately high tHcy levels (pools B1-B2). Between-lab comparability expressed as CV was 14.0% 13.9%, 15.6% and 14.5% for pools A1, A2, B1, and B2. These values were considerably lower (CV values < 5.2%) when a common plasma standard was used for calculation of tHcy levels, while the use of a common aqueous standard failed to achieve the necessary harmonization. In conclusion, performance characteristics of the FPIA method compare favorably with the well-established HPLC methods. It is simpler and more suitable to be used by general hematological labs. Between-lab comparability of results is still a problem. The establishment of an international plasma standard would be of help to harmonize tHcy measurement across laboratories.

Chromatography, High Pressure Liquid↗
PubMed2001

Measurement on Tinetti test: instrumentation and procedures.

A measurement system and associate signal processing procedures for quantifying subject's performance during the performance-oriented assessment of balance as defined in Tinetti test (TT) is described. It is based on two inclinometers measuring trunk inclination in two orthogonal planes. Signals from the transducers are acquired by a PC through A/DC board. Signal processing consists in computing morphological parameters describing the main features of subject movement during the different TT maneuvers. The system is simple, cheap, user friendly, causes no discomfort to the patient and can easily be modified to comply with either new requirements or the needs of other performance tests dealing with trunk movement. Preliminary results of measurements on both normals and patients suggest the viability of this approach and the possibility of discriminating normal from abnormal performance, based on the values of the morphological parameters.

Aged↗
PubMed2000

Rvs161p and Rvs167p, the two yeast amphiphysin homologs, function together in vivo.

Mutations in RVS161 and RVS167, the two yeast amphiphysin homologs, cause very similar growth phenotypes, a depolarized actin cytoskeleton, and a defect in the internalization step of endocytosis. Rvs161p and Rvs167p have been shown to interact in the two-hybrid system, but their localization in the cell may be different thus raising the question whether the interaction is physiologically relevant. Here we demonstrate that the two proteins function together in vivo. We find that the steady state level of Rvs167p is strongly reduced in an rvs161Delta strain. Similarly, the level of Rvs161p is strongly reduced in an rvs167Delta strain. We demonstrate that these reduced protein levels at steady state are due to a decreased stability of either Rvs protein in the absence of the other protein. Furthermore, we find that the amount and ratio of Rvs161p and Rvs167p are critical parameters for receptor-mediated endocytosis. In addition, by using the two-hybrid system we show that the interaction of Rvs167p with actin is not abolished in an abp1Delta strain suggesting that Abp1p is not essential for this interaction.

Actins↗
PubMed2000

Protein kinase C-dependent modulation of Na+ currents increases the excitability of rat neocortical pyramidal neurones.

The effect of the protein kinase C (PKC) activator 1-oleoyl-2-acetyl-sn-glycerol (OAG) on TTX-sensitive Na+ currents in neocortical pyramidal neurones was evaluated using voltage-clamp and intracellular current-clamp recordings. In pyramid-shaped dissociated neurones, the addition of OAG to the superfusing medium consistently led to a 30% reduction in the maximal peak amplitude of the transient sodium current (I(Na,T)) evoked from a holding potential of -70 mV. We attributed this inhibitory effect to a significant negative shift of the voltage dependence of steady-state channel inactivation (of approximately 14 mV). The inhibitory effect was completely prevented by hyperpolarising prepulses to potentials that were more negative than -80 mV. A small but significant leftward shift of INa,T activation was also observed, resulting in a slight increase of the currents evoked by test pulses at potentials more negative then -35 mV. In the presence of OAG, the activation of the persistent fraction of the Na+ current (INa,P) evoked by means of slow ramp depolarisations was consistently shifted in the negative direction by 3.9+/-0.5 mV, while the peak amplitude of the current was unaffected. In slice experiments, the OAG perfusion enhanced a subthreshold depolarising rectification affecting the membrane response to the injection of positive current pulses, and thus led the neurones to fire in response to significantly lower depolarising stimuli than those needed under control conditions. This effect was attributed to an OAG-induced enhancement of INa,P, since it was observed in the same range of potentials over which I(Na,P) activates and was completely abolished by TTX. The qualitative firing characteristics of both the intrinsically bursting and regular spiking neurones were unaffected when OAG was added to the physiological perfusing medium, but their firing frequency increased in response to slight suprathreshold depolarisations. The obtained results suggest that physiopathological events working through PKC activation can increase neuronal excitability by directly amplifying the I(Na,P)-dependent subthreshold depolarisation, and that this facilitating effect may override the expected reduction in neuronal excitability deriving from OAG-induced inhibition of the maximal INa, T peak amplitude.

Animals↗
PubMed2000

An intact SH3 domain is required for myosin I-induced actin polymerization.

The yeast type I myosins (MYO3 and MYO5) are involved in endocytosis and in the polarization of the actin cytoskeleton. The tail of these proteins contains a Tail Homology 2 (TH2) domain that constitutes a putative actin-binding site. Because of the important mechanistic implications of a second ATP-independent actin-binding site, we analyzed its functional relevance in vivo. Even though the myosin tail interacts with actin, and this interaction seems functionally important, deletion of a major portion of the TH2 domain did not abolish interaction. In contrast, we found that the SH3 domain of Myo5p significantly contributes to this interaction, implicating other proteins. We found that Vrp1p, the yeast homolog of WIP [Wiskott-Aldrich syndrome protein (WASP)-interacting protein], seems necessary to sustain the Myo5p tail-F-actin interaction. Consistent with recent results implicating the yeast type I myosins in regulating actin polymerization in vivo, we demonstrate that the C-terminal domain of Myo5p is able to induce cytosol-dependent actin polymerization in vitro, and that this activity requires both an intact Myo5p SH3 domain and Vrp1p.

Actins↗
PubMed2000

Platelets from a patient heterozygous for the defect of P2CYC receptors for ADP have a secretion defect despite normal thromboxane A2 production and normal granule stores: further evidence that some cases of platelet 'primary secretion defect' are heterozygous for a defect of P2CYC receptors.

Two unrelated patients with a congenital bleeding diathesis associated with a severe defect of the platelet ADP receptor coupled to adenylate cyclase (P2(CYC)) have been described so far. In one of them, platelet secretion was shown to be abnormal. We recently showed that platelets with the primary secretion defect (PSD; characterized by abnormal secretion but normal granule stores, thromboxane A(2) production, and ADP-induced primary wave of aggregation) have a moderate defect of P2(CYC). Therefore, the interaction of ADP with the full complement of its receptors seems to be essential for normal platelet secretion, and PSD patients may be heterozygotes for the congenital severe defect of P2(CYC). In this study, we describe 2 new related patients with a severe defect of P2(CYC) and the son of one of them, who is to be considered an obligate heterozygote for the defect. The 2 patients with the severe defect had lifelong histories of abnormal bleeding, prolonged bleeding times, abnormalities of platelet aggregation and secretion, lack of inhibition of adenylate cyclase by ADP, and a deficiency of platelet-binding sites for [(33)P]2 MeS-ADP (240 and 225 sites per platelet; normal range, 530 to 1102). The son of one of them had a mildly prolonged bleeding time and abnormalities of platelet aggregation and secretion similar to those found in patients with PSD. In addition, his platelets showed a moderate defect of binding sites for [(33)P]2 MeS-ADP (430 sites per platelet) and of adenylate cyclase inhibition by ADP. This study of a family with the platelet disorder characterized by a defect of the platelet P2(CYC) receptor supports our hypothesis that the full complement of the platelet ADP receptors is essential for normal platelet secretion and that some patients with the common, ill-defined diagnosis of PSD are actually heterozygous for the defect.

Adenosine Diphosphate↗
PubMed2000

[Extramedullary primary cutaneous plasmacytoma. Description of a case] .

Primary cutaneous plasmacytomas of the chest wall are very rare. In this report we describe a case of a 70-years old man, affected by chronic obstructive pulmonary disease and renal failure. He was admitted because of a painful tumor on the right lateral chest wall: a transcutaneous fine needle aspiration and excisional biopsy revealed as a metastasis from lung cancer without clinical and or radiological evidence of pulmonary tumors and or other neoplasms. Because of failure of chemotherapy, the patient had undergone to bone marrow biopsy that it revealed medullary plasmacytosis < 5% plasma cells with a beta 2 microglobulin elevated. An other following excisional biopsy of a chest wall with immunocytochemistry revealed to be a cutaneous plasmacytomas. The patient was treated with local irradiation for a total dose of 40 cGy and systemic chemotherapy, stopped because of death by myocardial infarction. Cutaneous plasmacytomas appear to be more aggressive than non cutaneous extramedullary plasmacytomas; they should be separately categorized from them in future studies.

Aged↗
PubMed1999

Evaluation of platelet function with the PFA-100 system in patients with congenital defects of platelet secretion.

The template bleeding time is still the screening test for defects of platelet function, although it is an invasive and poorly reproducible technique. The PFA-100 measures platelet function at high shear. Whole blood is aspirated through a capillary to an aperture of a membrane coated with platelet agonists. The system measures the time required to obtain occlusion of the aperture by a platelet plug (closure time). We measured the closure times in the PFA-100 system and the bleeding time in seven patients with delta-storage pool deficiency, 10 patients with "primary secretion defect" (not due to abnormalities of platelet granules or the arachidonate pathway), and 40 controls. Measurements were repeated I and 4 hours after intravenous infusion of desmopressin in six delta-storage pool deficiency and eight primary secretion defect patients. Baseline bleeding time and closure times with the collagen/epinephrine cartridge were longer in delta-storage pool deficiency and primary secretion defect patients than in controls. In contrast, closure times with the collagen/adenosine diphosphate cartridge were normal in both delta-storage pool deficiency and primary secretion defect patients. Treatment with desmopressin increased the plasma von Willebrand Factor levels, shortened the prolonged bleeding time, shortened the closure times with the collagen/adenosine diphosphate cartridge, and normalized the closure times with the collagen/ epinephrine cartridge. Therefore, the PFA-100 test may be a less invasive alternative to the bleeding time in the diagnosis and therapeutic monitoring of patients with platelet secretion defects. The collagen/epinephrine cartridge is more sensitive than the collagen/adenosine diphosphate cartridge to defects of platelet secretion.

Adult↗