PubMed Health⌕ Search

Biomedical subjects

J Irazuzta

Publications and source records attributed to J Irazuzta.

12 recordsLinked to original sources
PubMed2001

Hypothermia attenuates beta1 integrin expression on extravasated neutrophils in an animal model of meningitis.

Brain injury in meningitis occurs in part as a consequence of leukocyte migration and activation. Leukocyte integrins are pivotal in the inflammatory response by mediating adhesion to vascular endothelium and extracellular matrix proteins. We have demonstrated that moderate hypothermia early in the course of meningitis decreases leukocyte sequestration within the brain parenchyma. This study examines whether hypothermia alters neutrophil integrin expression in a rabbit model of bacterial meningitis. Prior to the induction of meningitis, peripheral blood samples were obtained and the neutrophils isolated. Sixteen hours after inducing group B streptococcal meningitis, animals were treated with antibiotics, i.v. fluids, and mechanically ventilated. Animals were randomized to hypothermia (32-33 degrees C) or normothermia conditions. After 10 hours of hypothermia or normothermia, neutrophils were isolated from the blood and cerebral spinal fluid (CSF), stained for beta1 and beta2 integrins, and analyzed using flow cytometry. Cerebral spinal fluid neutrophil beta1 integrin expression was significantly decreased in hypothermic animals. Beta-1 integrins can assume a higher affinity or "activated" state following inflammatory stimulation. Expression of "activated" beta1 integrins was also significantly decreased in hypothermic animals. Beta2 CSF neutrophil integrin expression was decreased in hypothermic animals, but failed to reach significance. These data suggest hypothermia may attenuate extravasated leukocyte expression of both total and "activated" beta1 integrins.

Animals↗
PubMed2000

Integrin expression on neutrophils in a rabbit model of Group B Streptococcal meningitis.

Products released by polymorphonuclear cells (PMNs) during an acute inflammatory response can result in diffuse tissue injury. Integrins are cell surface adhesion proteins that play a pivotal role in inflammation by allowing PMNs to adhere to the endothelium and migrate through the extracellular matrix. We examined the expression of beta1 and beta2 integrins on neutrophils from blood and cerebrospinal fluid (CSF) in an animal model of Group B Streptococcal meningitis. We further evaluated whether integrin expression correlates with pathophysiologic markers of central nervous system inflammation. Our data demonstrate that beta3 and beta2 integrin expression on circulating neutrophils does not significantly increase as a consequence of meningitis. In extravesated CSF neutrophils, a significant increase in expression of both beta1 and beta2 integrins is noted. Furthermore, a majority of the beta1 integrins on extravesated neutrophils have undergone affinity modulation. Using regression analysis, we demonstrated that increasing beta1 integrin expression correlates with decreasing CSF glucose concentration and serum/CSF glucose ratio. Regression analysis approached significance when CSF protein was compared to PMN beta1 integrin expression. Polymorphonuclear leukocytes beta1 integrin expression also showed a direct correlation to myeloperoxidase activity in brain tissue. Beta2 expression on CSF PMNs did not correlate with these markers of inflammation/sequestration. These data demonstrate integrin expression on extravesated neutrophils markedly increases during meningitis and support a role for beta1 integrins on neutrophils in the pathophysiologic consequences of meningitis.

Animals↗
PubMed2000

Evaluating the frequency rate of hypomagnesemia in critically ill pediatric patients by using multiple regression analysis and a computer-based neural network.

OBJECTIVES: To determine the frequency rate of hypomagnesemia in patients admitted to the pediatric intensive care unit (ICU), and to identify subsets of patients (grouped by disease) who are at greatest risk of hypomagnesemia. We also compared a neural network model with multiple regression analysis to identify independent variables that would correlate with hypomagnesemia and to predict serum magnesium values in critically ill pediatric patients overall. DESIGN: Prospective, multicenter study. SETTING: Tertiary level medical/surgical pediatric ICUs. PATIENTS: Data were obtained at admission to the pediatric ICU for 463 patients from newborn to 18 yrs old who were admitted with a variety of surgical and nonsurgical conditions. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Total serum magnesium values were obtained within the first 24 hrs after admission in 463 pediatric patients admitted to four pediatric ICUs. Hypomagnesemia (defined as total serum magnesium <0.75 mmol/L) was found in 51 (11%) of the 463 patients, with the highest frequency rate (72%) and lowest mean serum magnesium level (0.66 +/- 0.17 mmol/L) in patients admitted after surgery with extensive osseous involvement (spinal fusion and craniofacial reconstruction). To determine whether hypomagnesemia could be predicted on the basis of other laboratory and clinical criteria, multiple regression analysis was performed and showed age, weight, and albumin levels weakly associated (r2 = .14, p < .001) with magnesium levels within the different diagnostic groups. These data were used to produce a mathematical model able to predict magnesium levels within 5% of the actual values in 23% of patients. A neural network was also created to compare its predictive capabilities to those of the multiple regression model. Once trained on a random subset (85%) of the patient population, the neural network was able to predict magnesium levels to within 5% of actual values for 88% of the remaining 15% of patients, comparing favorably with the predictions derived from the multiple regression model. CONCLUSIONS: Hypomagnesemia is not uncommon (11%) in critically ill pediatric patients, but is very common (72%) in patients admitted after surgery for spinal fusion or craniofacial reconstruction. Patients who undergo surgery for correction of scoliosis and craniofacial anomalies should have serum magnesium levels monitored closely after surgery. In other patients, a neural network or multiple regression model could help predict which patients would be at risk of developing hypomagnesemia, thereby focusing testing on patients likely to benefit from such testing.

Adolescent↗
PubMed1998

Decrease in costs for management of lower airway disease in the pediatric intensive care unit.

BACKGROUND: We investigated whether a recently restructured pediatric intensive care unit (PICU) had a decrease in the cost of patient care over the years. METHODS: We retrospectively studied 89 previously healthy patients admitted to the PICU of a community-based, university-affiliated teaching hospital over a 4-year period (1991 to 1994) for treatment of lower airway disease. Data collected were patient age, severity of illness, length of stay in both PICU and hospital, prorated hospital bill, year of admission, and patient-specific PICU-originated costs (POC). RESULTS: There was a decrease of POC over the 4-year period, though two factors were associated with a cost increase in this group of patients: an increase in the severity of illness and intubation. The decrease over the years remained present even when excluding intubated patients and adjusting for severity of illness. A decline of 58% below the initial cost for diagnostic tests was the most prominent of all the individual areas studied. Decreases in POC correlated with decreases in the prorated hospital bill. CONCLUSIONS: The costs of management for these previously healthy patients treated for lower airway disease decreased over the study period. We speculate that the time related decrease in costs is a reflection of the learning curve of the pediatric critical care team. The decrease in POC did not shift costs to other areas of the hospital.

Asthma↗
PubMed1997

Simple method of multipurpose airway access through percutaneous tracheostomy in rabbits (Oryctolagus cuniculus).

Before percutaneous tracheostomy, rabbits were anesthetized and placed in the supine position with the head extended. A needle cricothyroidotomy was then performed. With the help of a guidewire and vessel dilator, a sheath introducer with sideport extension was secured into the airway. This system provided airway access for introduction or sampling of materials while the animal was breathing around the sheath introducer or through the sideport. This simple procedure was used successfully in more than 25 rabbits that recuperated and lived for several days without ongoing medical support.

Animals↗
PubMed1994

Neurologic deficits restored after elective posterior fossa decompression.

Arnold Chiari malformation is a condition in which the contents of the posterior fossa are herniated below the level of the foramen magnum, and it occurs in three basic forms. Patients with this condition frequently have obstructive hydrocephalus which requires a ventriculo-peritoneal shunt. This article describes the case of a infant female patient with Arnold Chiari Type I, who suffered an episode of acute hydrocephalus and neurologic deterioration after ventriculo-peritoneal shunt malformation. A shunt revision did not reverse her neurologic deficits, so a posterior fossa decompression was performed which did improve her condition.

Acute Disease↗
PubMed1993

Effects of fentanyl administration on respiratory system compliance in infants.

OBJECTIVE: To determine if the analgesic doses of fentanyl used in a pediatric intensive care unit (ICU) setting adversely affect dynamic total respiratory system compliance in awake, intubated infants. DESIGN: Prospective case-control study. SETTING: Pediatric and pediatric cardiac ICUs of a tertiary university hospital. PATIENTS: Thirteen awake and mechanically ventilated children < 6 months of age. INTERVENTIONS: Measurements of dynamic total respiratory system compliance were obtained during steady-state conditions for 6 mins and continued for 10 mins after the rapid, intravenous administration of 4 micrograms/kg of fentanyl. No patient had received a narcotic, benzodiazepine, or muscle relaxant within the previous 4 hrs. MEASUREMENTS AND MAIN RESULTS: After fentanyl administration, dynamic total respiratory system compliance was unchanged in three patients, improved in nine patients, and deteriorated in one patient. The mean value for the entire group increased from 0.76 mL/cm H2O/kg before infusion to 0.82 mL/cm H2O/kg after infusion (p < .02), representing a 9.6% increase. None of the patients showed oxygen desaturation as assessed by continuous pulse oximeter, or episodes of chest wall rigidity. CONCLUSIONS: This work corroborates our clinical impression that rapid infusions of fentanyl at the dose tested in small infants do not adversely affect dynamic total respiratory system compliance. To the contrary, the sedating and analgesic effects may improve synchronous breathing and decrease voluntary muscle tone, resulting in improved dynamic total respiratory system compliance.

Fentanyl↗
PubMed1983

C-reactive protein measurement: a reliable method of diagnosing and monitoring the infected newborn for the assessment of a mezlocillin therapeutic trial.

Clinical and bacteriological efficacy of mezlocillin was evaluated in 41 neonates (including 12 premature babies) with clinical and laboratory evidence of bacterial infection, as shown by elevated C-reactive protein serum concentrations. They received intravenous mezlocillin (80 to 100 mg/kg/dose) every 8 h for 10.4 days. The mean serum concentration (+/- S.E.M.) of mezlocillin in full-term neonates was 214 +/- 19.8 mg/l 1 h after the infusion and 52.0 +/- 9.3 mg/l prior to the next infusion. In premature neonates these mean concentrations were respectively 167 +/- 23.4 mg/l and 40.7 +/- 6.7 mg/l. The efficacy of mezlocillin was documented by the decrease in C-reactive protein serum concentrations and by improvement in clinical condition. Therapy with mezlocillin alone proved to be safe and effective when used for non-nosocomial infections during the neonatal period.

Bacteria↗
PubMedDate not supplied

Monitoring in pediatric intensive care.

Monitoring plays an essential role in the management of critically ill children, although continuous observation along with frequent clinical examination remains the best readily available monitor. Unfortunately, human beings do not have the capability of a prolonged, uninterrupted attention span and nurses often have multiple tasks assigned that limit their ability for continuous observation. Furthermore, some information cannot be obtained accurately by clinical examination alone, e.g. oxygen saturation, ICP, etc. Therefore, it is important to understand the principles and practical points to be able to use these monitors, and first rule out malfunction, disconnection, or improper electrode placement when abnormal reading appear on these monitors before initiating clinical intervention on a patient.

Child↗
PubMedDate not supplied

Compared contralateral application of topical nitroglycerin on purpura fulminans.

In cases of purpura fulminans (PF), various treatments have been used to prevent the cutaneous involvement and extensive skin necrosis that can be both disfuguring and debilitating. In this article, we present a case where improvement in the progression of purpuric areas was accomplished by topical administration of nitroglycerin (TNG), as evidenced by comparison with symmetrical contralateral areas not so treated.

Administration, Topical↗
PubMedDate not supplied

Utilization of diagnostic resources for meningoencephalitis in the pediatric ICU.

To determine whether a Pediatric Critical Care team has an evolution of medical practice that decreases the utilization of diagnostic tests and consults, we examined the records of 69 patients admitted for meningitis or meningoencephalitis at Women and Children's Hospital in Charleston, W.Va., a university-affiliated, teaching hospital. The study was conducted from August 1990 to August 1994. We found that utilization of diagnostic resources (UDR) decreased over the four years, and there was a direct relationship between an increase in severity of illness and an increase in UDR. When adjusted per severity of illness, UDR decreased by $423 per year. The presence of a consult was a factor leading to an increase in resources, which were associated with an increased utilization of diagnostic tests and length of stay. The consultation rate was independent of the severity of illness and experienced a decrease over the years.

Analysis of Variance↗