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Biomedical subjects

José G Merino

Publications and source records attributed to José G Merino.

11 recordsLinked to original sources
PubMed2006

Intra- and interrater reliability of ischemic lesion volume measurements on diffusion-weighted, mean transit time and fluid-attenuated inversion recovery MRI.

BACKGROUND AND PURPOSE: We investigated the intra- and interrater reliability of ischemic lesion volumes measurements assessed by different MRI sequences at various times from onset. METHODS: Ischemic lesion volumes were measured for intrarater reliability using diffusion-weighted (DWI), mean transit time (MTT) perfusion and fluid-attenuated inversion recovery (FLAIR) MRI at chronic (>3 days from stroke onset) time points. A single intrarater reader, blind to clinical information and time point, repeated the volume measurements on two occasions separated by at least 1 week. Interrater reliability was also obtained in the second set of patients using acute DWI, MTT and chronic FLAIR MRI. Four blinded readers performed these volume measurements. Average deviations across repeat measurements per lesion and differences between sample means between the two measurements were calculated globally, ie, across all sequences and time points, and per reader type for each sequence at each time point. RESULTS: There was good concordance of the mean sample volumes of the 2 intrarater readings (deviations were <4% and 2 mL globally, <2% and 2 mL for DWI, <6% and 7 mL for MTT, and <2% and 1 mL for FLAIR). There was also good concordance of the interrater readings (<5% and 2 mL globally). CONCLUSIONS: Repeat measurements of stroke lesion volumes show excellent intra- and interrater concordance for DWI, MTT and FLAIR at acute through chronic time points.

Brain Ischemia↗
PubMed2003

The Ischemic Stroke Genetics Study (ISGS) Protocol.

BACKGROUND: The molecular basis for the genetic risk of ischemic stroke is likely to be multigenic and influenced by environmental factors. Several small case-control studies have suggested associations between ischemic stroke and polymorphisms of genes that code for coagulation cascade proteins and platelet receptors. Our aim is to investigate potential associations between hemostatic gene polymorphisms and ischemic stroke, with particular emphasis on detailed characterization of the phenotype. METHODS/DESIGN: The Ischemic Stroke Genetic Study is a prospective, multicenter genetic association study in adults with recent first-ever ischemic stroke confirmed with computed tomography or magnetic resonance imaging. Patients are evaluated at academic medical centers in the United States and compared with sex- and age-matched controls. Stroke subtypes are determined by central blinded adjudication using standardized, validated mechanistic and syndromic classification systems. The panel of genes to be tested for polymorphisms includes beta-fibrinogen and platelet glycoprotein Ia, Iba, and IIb/IIIa. Immortalized cell lines are created to allow for time- and cost-efficient testing of additional candidate genes in the future. DISCUSSION: The study is designed to minimize survival bias and to allow for exploring associations between specific polymorphisms and individual subtypes of ischemic stroke. The data set will also permit the study of genetic determinants of stroke outcome. Having cell lines will permit testing of future candidate risk factor genes.

Academic Medical Centers↗
PubMed2003

Use of a field-to-stroke center helicopter transport program to extend thrombolytic therapy to rural residents.

BACKGROUND AND PURPOSE: Giving stroke victims who reside outside communities with hospitals that can administer tissue plasminogen activator (rtPA) access to thrombolytic therapy is a challenge. Helicopter transport to a stroke center is a potential way to make rtPA available to these communities. We examined the experience of the Shands-Jacksonville Acute Stroke Transport Program, a field-to-stroke center helicopter transport program that serves rural counties in the northeastern Florida/southeastern Georgia region. METHODS: Prospectively collected data of 111 consecutive helicopter transports to Shands-Jacksonville, from an 11-county region, over a 3-year period were reviewed. RESULTS: Eighty-five patients (76%) had a cerebrovascular event. Forty-seven patients (42%) had an ischemic stroke, 19 (17%) had a transient ischemic attack, and 19 (17%) had a hemorrhagic stroke. Thrombolytic therapy was administered to 18 ischemic stroke patients (38%), with 15 being treated intravenously. Three patients who arrived beyond the 3-hour window were treated intra-arterially. Average field-to-hospital distance for all patients was 29.4 miles (range, 11 to 90 miles). Most patients (n=65) arrived within 135 minutes from symptom onset. CONCLUSIONS: A helicopter-based transport system can link a rural region to a stroke center and promote access to thrombolytic therapy.

Adult↗
PubMed2002

Stroke-related dementia.

Three months after a stroke, one quarter to one third of patients meet operationalized criteria for dementia, and an even greater proportion have cognitive impairment short of dementia. A significant number of these patients had mental deterioration before the stroke, implying an underlying neurodegenerative process. Current diagnostic criteria do not reflect these facts, and in addition to artificially using cerebrovascular disease to differentiate Alzheimer's disease and vascular dementia, they do not allow researchers and clinicians to identify subjects at risk in the early stages of cognitive decline. To be clinically useful, a broader concept of cognitive impairment in the setting of vascular disease needs to be developed based on data collected prospectively using cohorts of stroke patients.

Clinical Trials as Topic↗
PubMed2002

Extending tissue plasminogen activator use to community and rural stroke patients.

BACKGROUND AND PURPOSE: Guidelines for intravenous tissue plasminogen activator (tPA) use in stroke emphasize the importance of limiting its use to facilities with imaging capabilities and stroke expertise. This prospective case series set out to evaluate the safety of tPA use in patients referred from rural communities to a tertiary center. METHODS: Prospective data of 82 consecutive patients treated with tPA in London, Ontario, were reviewed. RESULTS: Twenty-three patients were transferred to London from a rural hospital (non-London patients); 49 were first evaluated in a London emergency room (London ER); and 10 were inpatients in a London hospital at the time of stroke onset. Mean transfer time and distance to London for non-London patients were 89 minutes and 41 miles. Although symptom onset to London ER times were longer for non-London than for London ER patients (123 versus 53 minutes), the door to needle times were significantly shorter for the former (49 versus 95 minutes, P<0.005). Imaging to needle times were longer for London inpatients compared with London ER patients (55 versus 36 minutes, P=0.16). The proportion of patients with >4-point improvement on the NIH Stroke Scale or cure at 24 hours was 57%, with no difference among groups (P=0.46). The overall symptomatic hemorrhage rate at 36 hours was 2%. No significant differences in outcomes were observed at 3 months. CONCLUSIONS: This prospective study suggests that it is feasible and safe to treat rural patients referred to a tertiary care center with tPA, thus extending the benefits of thrombolysis for acute stroke to a wider population.

Aged↗
PubMedDate not supplied

Clinicians and the economic evaluation of health.

Papers dealing with the economic evaluation of health care have proliferated in the clinical literature. They provide an evidence-based element to help policy makers allocate resources among competing projects. These studies are generally done from a the perspective of a health provider (public or practice) or a public health professional, they do not take into account the special nature of the patient-physician relationship. The value of these studies for a clinician caring for an individual patient is questioned because the perspective used and the values measured represent those of society or a health provider, not those of patients. In addition, since cost-effectiveness analysis fails to take into account important societal ethical beliefs that are relevant to the care of individuals, its application to individual care is limited. Physicians should use these analyses when working as private or public policy makers, not as clinicians. The English version of this paper is available too at: http://www.insp.mx/salud/index.html.

Cost-Benefit Analysis↗
PubMedDate not supplied

[Laennec and the creation of auscultation signs].

Toward the end of the 18th century, clinical diagnosis in medicine shifted its focus from reliance on symptoms, which translates to subjective experience of illness, to signs, objective manifestations of pathologic changes. Several techniques were developed to elicit signs in clinical practice, and Laennec used them routinely. He palpated and prodded his patients to get an idea of changes in internal organs. He also applied his ear directly to his patient's chest to hear their heartbeat. On one occassion, he was unable to use these techniques and had the happy occurrence of rolling up a notebook to hear his patient's chest. This led him to hear a great number of new sounds. Through detailed observations, he was able to describe, classify, and correlate these sounds with autopsy findings, thus creating a new semiology of chest diseases. In this essay explore how in which Laennec created his instrument and system of signs of chest diseases, and how he was able to transmit his inventions to his colleagues.

Auscultation↗