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Biomedical subjects

A R Hansen

Publications and source records attributed to A R Hansen.

At least 19 recordsLinked to original sources
PubMed2001

A comparative study of the immunogold labeling on H(2)O(2)-treated and heated epoxy sections.

The purpose of this study was to compare the intensity of the immunogold labeling of H(2)O(2)-treated and heated epoxy sections. Renal swine tissue with glomerular immune complex deposits with reactivity against IgG was embedded in epoxy resin. Immunogold labeling with anti-IgG was performed on sections from these blocks. Some of these sections were treated by H(2)O(2), others were heated in a citrate solution, while some were not treated at all. Some epoxy sections, which had been exposed to both H(2)O(2) and heat, were also exposed to the same immunolabeling. The heated epoxy sections obtained an yield of specific immunogold labeling, which was twice as large as the labeling of the H(2)O(2)-treated sections. The yield of immunolabeling of the sections that had been exposed to both H(2)O(2) and heat was not significantly different from the sections that were only exposed to heat. The non-treated sections were very weakly labeled with anti-IgG. We believe that both H(2)O(2) and heat have the ability to break some chemical bonds between the epoxy resin and the antigens, but heating in citrate buffer has a larger potential in this respect than H(2)O(2). We interpret the results from the combined treatment with H(2)O(2) and heat in the following way; the bonds that are broken by H(2)O(2) will also be broken by heating in citrate solution. The practical significance of these results is that heating in citrate buffer is a more convenient method for enhancing the immunolabeling of epoxy sections than treatment with H(2)O(2).

Animals↗
PubMed2000

Plasminogen activator inhibitor-1: defining characteristics in the cerebrospinal fluid of newborns.

We measured plasminogen activator inhibitor-1 levels in the cerebrospinal fluid and plasma of newborns with and without posthemorrhagic hydrocephalus. We found that plasminogen activator inhibitor-1 levels in the cerebrospinal fluid of healthy newborns are <10 mg/mL but are greatly elevated in patients who have posthemorrhagic hydrocephalus and correlate directly with cerebrospinal fluid D-dimer and protein levels.

Enzyme-Linked Immunosorbent Assay↗
PubMed1998

CNS fibrinolysis: a review of the literature with a pediatric emphasis.

In vitro studies of cerebrospinal fluid indicate that normal cerebrospinal fluid contains very low levels of fibrinolytic enzymes but that fibrinolytic activity is higher in pathologic compared with normal conditions and in older compared with younger patients. Because of the low endogenous fibrinolytic activity of the central nervous system, intraventricular fibrinolytic therapy has been studied in adult and pediatric patients for the treatment of intraventricular hemorrhage/posthemorrhagic hydrocephalus and subarachnoid hemorrhage with secondary cerebral vasospasm. A review of the literature about endogenous and exogenous fibrinolysis studies of animals, adult humans, and pediatric humans reveals a record of predominant safety and efficacy. Although its use in the adult population for the treatment of subarachnoid hemorrhage with secondary vasospasm has become an accepted therapy in some centers, its use in the pediatric population is less common. It is no longer considered in the treatment of meningitis, but its role in the treatment of intraventricular hemorrhage/posthemorrhagic hydrocephalus is still being investigated.

Adult↗
PubMed1998

Medical management of neonatal posthemorrhagic hydrocephalus.

Posthemorrhagic hydrocephalus is a relatively common complication of premature birth. One third of patients who do not undergo spontaneous resolution require medical management aimed at normalizing intracranial pressure by correcting the imbalance between cerebrospinal fluid (CSF) production and drainage. Serial lumbar punctures intermittently remove CSF in bulk. Pharmacologic therapy decreases CSF production. Each of these therapies have attendant benefits and risks. For patients whose CSF absorption does not improve with growth and recovery, placement of an indwelling ventricular drain is ultimately required.

Cerebral Hemorrhage↗
PubMed1997

Intraventricular urokinase for the treatment of posthemorrhagic hydrocephalus.

This case series pilot study assessed the safety of intraventricular urokinase administration, alternating with cerebrospinal fluid (CSF) drainage. A secondary objective was to comment on whether this therapy achieves fibrinolysis, and whether this fibrinolysis is sufficient to prevent progression of hydrocephalus to requirement for ventriculoperitoneal shunt. Six preterm infants with progressive posthemorrhagic hydrocephalus requiring treatment with a ventricular drain received an infusion of intraventricular urokinase alternating with CSF drainage for 3 days. Of the 6 treated patients, the median gestation at birth was 26.5 weeks and the median age at treatment was 30 days. One patient had an elevation in CSF erythrocyte count most likely due to successful clot lysis. One patient had an elevated CSF leukocyte count consistent with transient meningeal irritation. No other side effects were noted. Fibrinolysis was achieved in the CSF, as documented by markedly elevated D-dimer levels. Clot size diminished ultrasonographically. However, all 6 patients eventually required a ventriculoperitoneal shunt. We conclude that intermittent infusion of intraventricular urokinase alternating with periods of CSF drainage is probably a safe way to achieve a fibrinolytic state. However, when administered at the relatively late point in the neonatal course when a ventricular drain is required, this fibrinolytic state is not sufficient to decrease the requirement for ventriculoperitoneal shunt.

Age of Onset↗
PubMed1997

Predictors of ventriculoperitoneal shunt among babies with intraventricular hemorrhage.

We aimed to identify medical care practices that influence the need for ventriculoperitoneal shunt among infants who develop intraventricular hemorrhage. We reviewed the medical records of 82 babies with ultrasonographically documented intraventricular hemorrhage. We compared the 10 babies who required a ventriculoperitoneal shunt to the 72 controls who had intraventricular hemorrhage, but did not require a ventriculoperitoneal shunt or die, prior to discharge. We considered maternal, perinatal, and neonatal risk factors as potential predictive variables. Maternal preeclampsia, prenatal steroids, and cesarean delivery were associated with a reduced risk of shunt. Patients who did require a shunt were more likely than their nonshunted peers to be treated with dopamine, to receive greater volumes of total intravenous fluid, largely as albumin and red blood cells, and to have a higher incidence of acidosis, patent ductus arteriosus and systolic hypertension. Previously identified antecedents and correlates of intraventricular hemorrhage appear also to be the antecedents and correlates of progression to ventriculoperitoneal shunt among infants with intraventricular hemorrhage. These findings are consistent with the possibility that prenatal and postnatal care practices influence the risk for ventriculoperitoneal shunt among babies with intraventricular hemorrhage. This offers the promise that changes in obstetric and neonatal care will reduce the need for ventriculoperitoneal shunt in very low birthweight infants.

Cerebral Hemorrhage↗
PubMed1995

Field triage of trauma patients based upon the ability to follow commands: a study in 29,573 injured patients.

UNLABELLED: If a trauma system is to deliver "the right patient to the right hospital at the right time," a simple triage tool that can be used in the field to rapidly identify patients with a significant risk of morbidity and mortality is vital. OBJECTIVE: The purpose of this study was to evaluate the effectiveness of the Glasgow Coma Scale's Motor Response Component (GMR) in identifying such patients. METHODS: From patient records in a well established state trauma registry, the predictive power of the Glasgow Motor Score was compared with the predictive power of the Injury Severity Score (ISS), Trauma Score, and whole Glasgow Coma Scale Score (GCS), using discriminant analysis and logistic regression. RESULTS: Complete data were available for analysis for 29,573 patients. Nine percent died. The analyses demonstrated that the GMR was almost as good as the TS and better than the other scores in identifying patients at risk of dying. The highest discriminant accuracy was obtained by predicting that patients with a GMR of 6 would live and that all others (GMR 1-5) were at risk of dying. This means separating patients according to whether or not they follow simple commands. CONCLUSIONS: The study demonstrated the GMR to be a good predictor of mortality in injured patients. Patients at risk of dying can best be identified by separating patients into those who cannot follow simple commands (GMR 1-5) from all others. This rapid and simple assessment could be useful as a prehospital tool to identify patients at risk of dying. First responders and nonmedical personnel not skilled in the use of the Trauma Score can easily determine if victims are able to follow commands and potentially identify the patients who are likely to require urgent trauma center care.

Glasgow Coma Scale↗
PubMed1991

Acute ethanol intoxication decreases the likelihood of resuscitation from cardiac arrest in rats.

BACKGROUND AND METHODS: Acute ethanol intoxication has been shown to depress myocardial performance in both laboratory and clinical studies. The present study was designed to examine the effect of acute ethanol intoxication on resuscitation of rats subjected to cardiac arrest. Rats were given 1.2 g ("moderately intoxicated") or 2.4 g ("highly intoxicated") of ethanol/kg, or distilled water ("nonintoxicated" rats). Using a standardized technique, we induced cardiac arrest. CPR was then attempted using chest compressions interposed with abdominal compressions. Resuscitation was said to be successful if BP returned spontaneously within 6 mins of institution of chest compressions interposed with abdominal compressions, and if systolic BP was 50% of its prearrest level within 10 mins of discontinuation of chest compressions interposed with abdominal compressions. Mean +/- SD serum ethanol levels were 121.3 +/- 12.9 mg/dL (26.3 +/- 2.8 mmol/L) (moderately intoxicated rats) and 254.4 +/- 34.6 mg/dL (55.2 +/- 7.5 mmol/L) (highly intoxicated rats). RESULTS: Resuscitation was successful in 75% (15/20) of nonintoxicated rats, 46.7% (7/15) of moderately intoxicated rats, and 33.3% (5/15) of highly intoxicated rats. The difference in resuscitation rates was significant for nonintoxicated rats compared with either intoxicated rats as a group (p = .021) or highly intoxicated rats (p = .019), but was not significant for nonintoxicated rats compared with moderately intoxicated rats. CONCLUSION: Acute ethanol intoxication appears to decrease the likelihood of successful resuscitation in a dose-dependent fashion.

Alcoholic Intoxication↗
PubMed1991

Infections resulting from animal bites.

Animal bites are a major public health problem. This article reviews the epidemiology and treatment of animal bites. The epidemiology, clinical presentation, and treatment of infections caused by Pasteurella multocida and Capnocytophaga canimorsus (DF-2) are reviewed in detail.

Animals↗
PubMed1990

Complications in the emergency transport of pregnant women.

Emergency transport of pregnant women is increasing in frequency. The physiologic changes of pregnancy cause a gravid woman and her fetus to be particularly vulnerable during transport. As the uterus enlarges, it compresses the vena cava and the aorta of the mother when she is in the supine position. Aortocaval compression may lead to uteroplacental insufficiency, supine hypotension, and potentially cardiopulmonary arrest. In addition, aortocaval compression is associated with placental abruption. This report presents three cases that illustrate the tragic outcomes of transporting pregnant women in the supine position. Pregnant women should be transported in a position of lateral tilt.

Abruptio Placentae↗
PubMed1986

The potentiating effects of alcohol on driver injury.

It is well established that alcohol (ethanol) is associated with increased probability of traumatic injury. This relationship has been attributed to alcohol's impairment of judgment and psychomotor performance, leading to increased probability of an injury-producing mishap. Once an accident occurs, it is widely believed that alcohol may protect against injury. However, controlled laboratory studies using animal models indicate that alcohol exacerbates the injurious effects of trauma. In this study, detailed analysis of data from more than 1 million drivers involved in motor vehicle crashes indicates that when the effects of injury-related variables such as safety belt use, vehicle deformation, vehicle speed, driver age, and vehicle weight are taken into account, the drinking driver is more likely to suffer serious injury or death compared with the nondrinking driver. These findings do not support the widespread belief that alcohol is protective against injury, but rather indicate that alcohol increases vulnerability to injury in any given crash.

Accidents, Traffic↗
PubMed1986

Effect of nifedipine on cerebral high-energy phosphates after cardiac arrest and resuscitation in the rat.

We studied the effect of nifedipine, a calcium entry blocker, on the recovery of cerebral adenosine triphosphate (ATP), creatine phosphate (CP), and lactate levels following resuscitation from cardiac arrest. Using the cardiac arrest and resuscitation model of de Garavilla, Babbs, and Tacker with an arrest time of eight minutes, 76% of the animals arrested were resuscitated with an average intermittent abdominal compression-CPR time of 3.3 minutes. Rats were assigned randomly to the following groups: nonischemic; eight minutes of arrest without resuscitation; and postresuscitation treatment with either IV normal saline; 3 micrograms/kg nifedipine; 10 micrograms/kg nifedipine; or 30 micrograms/kg nifedipine. Treated animals were sacrificed at either 20 or 120 minutes thereafter. As expected, after eight minutes of cardiac arrest, the levels of ATP and CP dropped to near 0 and rebounded in all resuscitated animals. By 120 minutes after resuscitation, rats given the 10-micrograms/kg dose of nifedipine had levels of ATP equivalent to nonischemic values. Return of CP values to nonischemic levels was seen only at the 3-micrograms/kg dose and was independent of time of measurement. The ATP and CP levels in these nifedipine-treated groups were significantly better when compared to saline-treated controls. There were no treatment-dependent differences in lactate levels. We conclude that clinically appropriate doses of nifedipine had a beneficial effect on the recovery of cerebral high-energy phosphates after cardiac arrest and resuscitation.

Adenosine Triphosphate↗
PubMed1984

Effect of ethanol on lactic acidosis in experimental hemorrhagic shock.

Many trauma victims who have hemorrhagic shock are also intoxicated. Ethanol could worsen the severity of shock and decrease the amount of blood loss necessary to reach or maintain the shock state, perhaps by increasing lactic acidosis. We examined the effect of ethanol on lactic acidosis in a group of rats that were intoxicated, then put in a state of hemorrhagic shock (MAP = 40 mm Hg). These animals were compared to a control group that were in a similar state of hemorrhagic shock but not intoxicated. The volumes of blood necessary to reach and maintain the predetermined model state of shock for two hours in each group were also measured. The animals were paralyzed and placed on controlled ventilation. The ethanol produced an expected baseline lactic acidosis, and it took significantly less blood volume loss to keep the intoxicated group in shock. However, during shock there was no significant difference in the state of lactic acidosis. These results suggest that acute ethanol intoxication made the animals more sensitive to hemorrhage. This effect was not mediated by an increase in lactic acidosis in our model.

Acidosis↗
PubMed1984

Sudden death in a child with an occult hindbrain malformation.

Chiari type I malformation in previously asymptomatic children can contribute to sudden death. We report a case of a 3-year-old child with this syndrome who died 48 hours after an apparently mild head injury. The case illustrates that, in children with abnormal head size or shape, it may be important to obtain skull films after even minimal craniocerebral trauma.

Arnold-Chiari Malformation↗