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Biomedical subjects

M Giacomini

Publications and source records attributed to M Giacomini.

At least 37 records · Page 2Linked to original sources
PubMed2000

Application of artificial neural network for the identification of fresh water bacteria.

A method based on artificial neural network (ANN) for monitoring aquatic bacteria which would be useful for health care is presented. Environmental micro-organisms include a large number of taxa. Some species that normally are not pathogenic can represent a risk in certain conditions, such as old people and immuno-compromised individuals. A system based on unsupervised ANN has been set up using the fatty acid profiles of standard strains, obtained by gas-chromatography, as learning data. The Kohonen output map resulted in a powerful tool for identification of fresh isolates coming from a line of the major civil water system of Genova (Italy).

Bacteria↗
PubMed2000

Application of Kohonen neural network for the elaboration of electrogastrograms.

A method is presented for processing and analysis of electrogastrography (EGG) a noninvasive technique by which gastric myolectrical activity is recorded using abdominal surface electrodes. The analysis is based on FFT and on unsupervised artificial neural networks. Three kinds of patterns can be identified on the neurons of a Kohonen output map with 32 x 16 neurons: one relating to noisy spectral profiles, one relating to pre-prandial profiles, one relating post-prandial profiles. It is concluded that the described method is reliable and can be used for objective automated analysis of EGG and for investigation of possible relations of the EGG with gastric pathologies.

Diagnosis, Computer-Assisted↗
PubMed1999

Life support in the intensive care unit: a qualitative investigation of technological purposes. Canadian Critical Care Trials Group.

BACKGROUND: The ability of many intensive care unit (ICU) technologies to prolong life has led to an outcomes-oriented approach to technology assessment, focusing on morbidity and mortality as clinically important end points. With advanced life support, however, the therapeutic goals sometimes shift from extending life to allowing life to end. The objective of this study was to understand the purposes for which advanced life support is withheld, provided, continued or withdrawn in the ICU. METHODS: In a 15-bed ICU in a university-affiliated hospital, the authors observed 25 rounds and 11 family meetings in which withdrawal or withholding of advanced life support was addressed. Semi-structured interviews were conducted with 7 intensivists, 5 consultants, 9 ICU nurses, the ICU nutritionist, the hospital ethicist and 3 pastoral services representatives, to discuss patients about whom life support decisions were made and to discuss life-support practices in general. Interview transcripts and field notes were analysed inductively to identify and corroborate emerging themes; data were coded following modified grounded theory techniques. Triangulation methods included corroboration among multiple sources of data, multidisciplinary team consensus, sharing of results with participants and theory triangulation. RESULTS: Although life-support technologies are traditionally deployed to treat morbidity and delay mortality in ICU patients, they are also used to orchestrate dying. Advanced life support can be withheld or withdrawn to help determine prognosis. The tempo of withdrawal influences the method and timing of death. Decisions to withhold, provide, continue or withdraw life support are socially negotiated to synchronize understanding and expectations among family members and clinicians. In discussions, one discrete life support technology is sometimes used as an archetype for the more general concept of technology. At other times, life-support technologies are discussed collectively to clarify the pursuit of appropriate goals of care. CONCLUSIONS: The orchestration of death involves process-oriented as well as outcome-oriented uses of technology. These uses should be considered in the assessment of life-support technologies and directives for their appropriate use in the ICU.

Attitude of Health Personnel↗
PubMed1999

Qualitative modelling of the response of cytoskeletal actin filaments in endothelial cells subjected to shear stress.

An approach to modelling cytoskeletal function based on qualitative process theory and qualitative algebra is presented. A computer environment for qualitative modelling and simulation of physical systems, specifically oriented to the construction of biomedical knowledge bases, is used. The system that is being set up for the cytoskeleton is intended to serve as a tool for testing assumptions about cytoskeletal function, for the evaluation of experimental data and for planning experimental work. The aspects of cytoskeletal function that have been modelled so far are focal adhesion and the reorganisation of the vascular endothelial cell cytoskeleton in response to fluid-imposed shear stress. Starting from a natural language description, the subsequent levels of analysis leading to the formal structural description and the resulting implementation for these aspects within the development environment are presented.

Actins↗
PubMed1999

Level of human immunodeficiency virus DNA in peripheral blood mononuclear cells correlates with efficacy of antiretroviral therapy.

A novel colorimetric assay was developed and validated for accurate quantitation of human immunodeficiency virus (HIV) DNA in peripheral blood mononuclear cells (PBMCs). We tested 318 sequential samples from 56 subjects, 53 of whom were undergoing dual or triple therapy. Patients were considered responders when viremia levels were below 5, 000 HIV RNA copies/ml. The mean DNA copy numbers for untreated and responder subjects were similar (72 and 75, respectively), while it was 4.54-fold higher for nonresponders (339). This report provides strong evidence that HIV DNA levels in PBMCs correlate with therapeutic efficacy and suggests that DNA quantitation is a useful tool to monitor the decay of the HIV reservoir toward disease remission, especially when viremia is undetectable.

Anti-HIV Agents↗
PubMed1999

Home telecare.

Technology can be used to help the care of people at home in many ways and home health care is one of the fastest growing areas of health-care provision. Home-based technology has two main facets: passive monitoring and active measurement. Technical solutions must be acceptable to both the health-care staff and the assisted person, and should supplement not replace human carers. Other important aspects of technical solutions are: simplicity of operation and management, availability, reliability and affordability. The introduction of a home telecare system always requires changes in organization, since it is not enough simply to transmit data. The data must be received and interpreted, and advice for care must be provided. The most important aspects of home telecare are: organization and training; improving the quality of care; improving the quality of life; economy; and technology.

Cardiovascular Diseases↗
PubMed1999

Data integration to assist gastric emptying data analysis.

The diagnosis of dyspepsia is very difficult because the symptoms are clinically aspecific and the gastric emptying time tests are of complex interpretation. An integrated and automated analysis of clinical and instrumental data may improve the diagnostic process. We present a system to collect data on dyspeptic patient from different sources which has been set up to assist the clinician in the diagnosis of dyspepsia. The data base integrates a wide set of symptoms with data coming from laboratory tests. Moreover, we assess the feasibility of classifying gastric emptying profiles using both octanoid acid excretion data and electrogastrography.

Adult↗
PubMed1999

ArchAIDS connects a clinical department and a virological laboratory to automatize the follow up of AIDS patients.

A communication system for the automation of the follow up of AIDS patients set up by DIST at the Molecular Virology Unit in the Advanced Biotechnology Centre of Genova and at the Department of Internal Medicine of the Medical School of Genova is presented. This system includes a distributed database to store both clinical and virological data and a set of procedures to transfer patient data with a complete respect of requirements about completeness and privacy.

Acquired Immunodeficiency Syndrome↗
PubMed1999

An integration system to rapidly identify aquatic bacteria.

An identification system for aquatic bacteria which would be useful for aspects ranging from pollution monitoring to health care, is described. It contains relevant information concerning the nature, taxonomy and activity of aquatic bacteria and allows to identify fresh isolates by means of their chemotaxonomic profiles. The system is simple and user friendly, so that it can be used by people not familiar with computers and has a modular interface that allows an easy interaction with laboratory instruments. The system is also connected with artificial neural network based programs to identify strains starting from the considered chemotaxonomic features.

Bacteria↗
PubMed1998

A novel and innovative quantitative kinetic software for virological colorimetric assays.

This study addresses the limited range of quantification with colorimetric assays (ELISA) starting from the analysis of color production in a reference external curve. An automatic ELISA management software, designated Quanti-Kin Detection System (QKDS) is described, which retains the sensitivity of the end-point reading and extends the dynamic range up to five logarithms with mathematical interpretation of color production. The QKDS software is a generic system suitable for different types of ELISA with substrate incubation at room temperature, does not require dedicated instruments, performs accurate quantification (including assay quality control) and has a user friendly interface. Specific applications were developed for three types of analytes: antibodies, viral antigens and nucleic acids. Data are presented on three representative QKDS applications to HIV antibodies, p24 antigen and proviral DNA kits. The precision of quantification is strictly correlated with the precision of the kit; however, for almost all samples with known analyte amount, the error percentage was below 10%, only for two cases in quantification of HIV proviral DNA the error percentage was around 25%. The necessity for a wide quantification range has been demonstrated by measuring clinical samples, which showed a distribution in all possible quantification ranges for all kits.

Animals↗
PubMed1998

Intratracheal pulmonary ventilation at low airway pressures in a ventilator-induced model of acute respiratory failure improves lung function and survival.

STUDY OBJECTIVE: The pulmonary parenchyma in patients with acute respiratory failure (ARF) is commonly not involved in a homogenous disease process. Conventional mechanical ventilation (MV) at elevated positive end-expiratory pressure (PEEP) and peak inspiratory pressure (PIP) aims at recruiting collapsed or nonventilated lung units. Invariably, those pressures are also transmitted to the healthiest regions, with possible extension of the disease process (barotrauma). During intratracheal pulmonary ventilation (ITPV), a continuous flow of fresh gas is delivered directly at the carina, bypassing the dead space proximal to the catheter tip. In healthy sheep, it allows lowering tidal volume (VT) to as low as 1.0 mL/kg, at respiratory rates (RR) up to 120 breaths/min, while maintaining normocapnia. In a model of ventilator-induced lung injury, we wished to explore whether ITPV, applied at low VT and low PEEP and tailored to ventilate the healthiest regions of the lungs, could provide adequate oxygenation and alveolar ventilation, without any attempt to recruit lungs. DESIGN: Randomized study in sheep. SETTING: Animal research laboratory. PARTICIPANTS: We induced ARF in 12 sheep following 1 to 2 days of MV at a PIP of 50 cm H2O, except that 5 to 8% of lungs were kept on apneic oxygenation of 5 cm H2O, sparing those regions from the injury process. INTERVENTIONS: Sheep were randomized to volume-controlled MV (control group) (n = 6) with VT of 8 to 12 mL/kg, PEEP of 5 to 10 cm H2O, or to ITPV (n = 6) at PEEP of 3 to 5 cm H2O, VT of 2.5 to 4 mL/kg, PIP of <20 cm H2O, at RRs sufficient to sustain normocapnia. MEASUREMENTS AND RESULTS: Hemodynamic status in the ITPV group progressively improved, and all six sheep were weaned to room air within 83+/-54 h. Sheep in the control group had progressively deteriorating conditions and all animals died after a mean of 50+/-39 h. Barotrauma and postmortem histopathologic changes were more pronounced in the control group. CONCLUSION: In this model of ventilator-induced lung injury, low PEEP-low VT ventilation with ITPV sustained normocapnia and prevented further lung injury, allowing weaning to room air ventilation.

Acute Disease↗
PubMed1997

A change of heart and a change of mind? Technology and the redefinition of death in 1968.

In 1968, an ad hoc committee of Harvard faculty publicly redefined death as "brain death". What interests and issues compelled the redefinition of death, and formed the "spirit" of this precedent-setting policy? This paper reports on an historical study of the files of the Harvard ad hoc committee, the proceedings of an international conference on ethical issues in organ transplantation, and a review of the medical literature and media in the decades preceding the redefinition of death. This analysis of the technological and professional forces involved in the redefinition of death in 1968 questions two common theses: that technological "progress", primarily in the areas of life support and electroencephalography, literally created brain-dead bodies and dictated their defining features (respectively), and that Harvard's definition of brain death by committee constituted a net loss of autonomy for medicine. In fact, medical researchers through the 1960s disputed and negotiated many features of the brain death syndrome, and transplantation interests-perhaps more kidney than heart-played a particularly influential role in tailoring the final criteria put forth by Harvard in 1968. It is also doubtful whether Harvard's definition of brain death by multidisciplinary committee undermined medical privilege and autonomy. The Harvard Ad Hoc Committee may not have succeeded in establishing definitive, indisputable brain death criteria and ensuring their consistent application to all clinical cases of brain death. However, it did gain significant ground for transplant and other medical interests by (1) establishing brain death as a technical "fact" and the definition of brain death as an exercise for medical theorists, (2) involving non-medical ethics and humanities experts in supporting the technical redefinition of death, and, (3) successfully involving transplant surgeons in the redefinition of death and attempting (albeit unsuccessfully) not to exclude them from the actual diagnosis of death in individual cases.

Brain Death↗
PubMed1997

Clearance of mucus from endotracheal tubes during intratracheal pulmonary ventilation.

BACKGROUND: Intratracheal pulmonary ventilation (ITPV) is a form of tracheal gas insufflation in which all gas emerges in a cephalad direction from the tip of a reverse-thrust catheter positioned within an endotracheal tube. In vitro experiments have shown that this rapid gas flow, with 5 ml/h of normal saline added to the gas flow, continuously removes tracheal secretions from within the endotracheal tube. The authors evaluated its effectiveness to remove mucus in long-term studies in sheep. METHODS: Fourteen healthy sheep were tracheally intubated and ventilated for 3 days with ITPV or with volume-controlled ventilation. Measurements were made of the total amount of secretions within the endotracheal tubes (weight gain), the protein content within the endotracheal tubes, and the increase in resistance to constant air flow. The structure of the airways was examined grossly and histologically. Three additional sheep were ventilated for 24 h with ITPV, and Evans Blue dye was added to the saline to assess the distribution of the infused saline. RESULTS: There was significantly less mucus in endotracheal tubes of sheep ventilated with ITPV than with conventional ventilation, as shown by minimal weight gain (0.70 +/- 0.14 g vs. 2.44 +/- 0.81 g; P < 0.001), lower protein content (14.09 +/- 10.79 mg vs. 294.99 +/- 153.06 mg; P < 0.001), and lower resistance to constant air flow (6.15 +/- 0.54 cm H2O x 1(-1) x s(-1) vs. 15.34 +/- 5.28 cm H2O x 1(-1) x s(-1); P < 0.001). Results of gross and histological examinations of the tracheas of animals in both groups were similar, and the tracheas were well preserved. More than 95% of the instilled saline was recovered during ITPV. Only traces of Evans Blue dye were found near the tip of the endotracheal tubes. CONCLUSION: Intratracheal pulmonary ventilation makes it possible to keep the endotracheal tubes of sheep ventilated for 3 days free of mucus without suctioning.

Animals↗
PubMed1997

Artificial neural network identification of heterotrophic marine bacteria based on their fatty-acid composition.

The traditional approach to biochemical identification of marine fresh isolates requires considerably long culture preparation times and large quantities of expensive materials and reagents, and the results are not reliable. On the other hand, taxonomy tests based on DNA composition, although sensitive and reliable, require long execution time and high costs. A method is presented for the classification of fatty-acid profiles, extracted from marine bacteria strains, at genus level based on supervised artificial neural networks. The proposed method allows the correct identification of all patterns belonging to the test set. Moreover, a quantitative measure of the importance of each fatty acid for bacterial classification is also achieved. This measure allows the determination of a cluster of fatty acids to be controlled with greater care. The results show that the proposed method is reproducible and rapid, so that it can be routinely used in the marine microbiology laboratory to identify fresh isolates.

Algorithms↗
PubMed1997

Medical necessity in Canadian health policy: four meanings and ... a funeral?

Four meanings of medical necessity have emerged, evolved, and dominated past and current health policy debates about the appropriate level of service coverage under Canada's health insurance program. To explore the shift in definition, provincial government and national health care association position papers responding to federal legislative and policy reviews of Canada's health insurance program from 1957 to 1984 were examined, as were more current reports on medical necessity. Four meanings of medical necessity predominated: "what doctors and hospitals do"; "the maximum we can afford"; "what is scientifically justified"; and "what is consistently funded across all provinces." These meanings changed with time as different stakeholder associations and governments redefined the concept of medical necessity to achieve different policy objectives for health service coverage under Canada's health insurance program.

Attitude to Health↗
PubMed1997

Intratracheal pulmonary ventilation and continuous positive airway pressure in a sheep model of severe acute respiratory failure.

STUDY OBJECTIVES: Previously we have shown that optimal pulmonary gas exchange can be sustained at normal airway pressures in a model of severe acute respiratory failure (ARF), using intratracheal pulmonary ventilation (ITPV), with weaning to room air. In an identical model of ARF, we have now explored whether ITPV, combined with continuous positive airway pressure (CPAP), can sustain adequate ventilation, with weaning to room air. DESIGN: Randomized study in sheep. SETTING: Animal research laboratory at the National Institutes of Health. INTERVENTIONS: ARF was induced in 12 sheep, using mechanical ventilation at peak inspiratory pressure of 50 cm H2O, but excluding 5 to 8% of lungs. Sheep were then randomized into two groups: the CPAP-ITPV group (n=6), in which ITPV was combined with a novel CPAP system; and a control group (n=6) in which the same CPAP circuit was used, but without ITPV. MEASUREMENTS AND RESULTS: All sheep in the CPAP-ITPV group were weaned to room air in 38.7+/-14 h. PaO2/fraction of inspired oxygen (FIO2) progressively increased from 108.8+/-43 to 355.7+/-93.1; PaCO2 remained within normal range; respiratory rate (RR) ranged from 18 to 120 breaths/min, and tidal volume (VT) was as low as 1.1 mL/kg. All sheep in the control group (CPAP alone) developed severe respiratory acidosis and hypoxemia after 4.8+/-4 h. PaO2/FIO2 decreased from 126.6+/-58.2 to 107.2+/-52.5 mm Hg, with a final PaCO2 of 166.8+/-73.3 mm Hg. CONCLUSIONS: All sheep treated with CPAP-ITPV maintained good gas exchange without hypercapnia at high RR and at low VT, with weaning to room air. All control animals treated with CPAP alone developed severe hypercapnia, respiratory acidosis, and severe hypoxemia, and were killed.

Acidosis, Respiratory↗