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Biomedical subjects

D L Stewart

Publications and source records attributed to D L Stewart.

At least 91 records · Page 5Linked to original sources
PubMed1971

International reference preparation of anti-Mycoplasma gallisepticum serum.

The WHO Expert Committee on Biological Standardization requested the Central Veterinary Laboratory, Weybridge, England, to arrange a collaborative assay of material they had prepared to determine its suitability to serve as an international reference preparation of anti-Mycoplasma gallisepticum serum. Fourteen laboratories in eight countries performed comparative assays of the proposed reference preparation together with 3 immune sera from fowls. On the basis of the results obtained, the Committee established the preparation as the International Reference Preparation of Anti-Mycoplasma gallisepticum Serum and defined the International Unit as the activity contained in 0.0556 mg of the International Reference Preparation.

Agglutination Tests↗
PubMed1968

International reference preparation of anti-Newcastle-disease serum.

The Central Veterinary Laboratory, Weybridge, England, was requested by the WHO Expert Committee on Biological Standardization to obtain suitable material for an international reference preparation of anti-Newcastle-disease serum for standardizing the haemagglutination-inhibition test for Newcastle disease and to arrange a collaborative assay. Ten laboratories in 10 countries assayed a batch of immune chicken serum against 2 test preparations. On the basis of the results obtained, the material has been established as the International Reference Preparation of Anti-Newcastle-Disease Serum and the International Unit of Anti-Newcastle-Disease Serum has been defined as the activity contained in 0.1734 mg of the International Reference Preparation of Anti-Newcastle-Disease Serum.

Animals↗
PubMed1968

International reference Preparation of Newcastle Diseaase Vaccine (Live).

The Central Veterinary Laboratory, Weybridge, England, was requested by the WHO Expert Committee on Biological Standardization to arrange a collaborative assay to test a freeze-dried preparation of live Newcastle disease vaccine (Hitchner B1 strain) for its suitability to serve as an international reference preparation. Nine laboratories in 8 countries assayed the vaccine against a number of test preparations of different vaccine strains. On the basis of the results obtained, the material has been established as the International Reference Preparation of Newcastle Disease Vaccine (Live) and is considered suitable for standardizing the titration of the Hitchner B1 strain and related strains of virus.

Immunoassay↗
PubMed1968

International standard for anti-canine-hepatitis serum.

The Central Veterinary Laboratory, Weybridge, England, was requested by the WHO Expert Committee on Biological Standardization to obtain suitable material for an international standard for anti-canine-hepatitis serum and to arrange a collaborative assay. Eight laboratories in 7 countries assayed a batch of anti-canine-hepatitis serum against 3 test preparations. On the basis of the results obtained, the material has been established as the International Standard for Anti-Canine-Hepatitis Serum and the International Unit of Anti-Canine-Hepatitis Serum has been defined as the activity contained in 0.0796 mg of the International Standard.

Animals↗
PubMed1968

International standard for anti-canine-distemper serum.

The Central Veterinary Laboratory, Weybridge, England, was requested by the WHO Expert Committee on Biological Standardization to obtain suitable material for an international standard for anti-canine-distemper serum and to arrange a collaborative assay. Seven laboratories in 6 countries assayed a batch of anti-canine-distemper serum against 3 test preparations. On the basis of the results obtained, the material has been established as the International Standard for Anti-Canine-Distemper Serum and the International Unit of Anti-Canine-Distemper Serum has been defined as the activity contained in 0.0897 mg of the International Standard.

Animals↗
PubMedDate not supplied

Timing of intracranial hemorrhage during extracorporeal life support.

This study was conducted to determine the timing of intracranial hemorrhage (ICH) in patients on extracorporeal life support (ECLS) to improve the use of the head ultrasound in the detection of ICH. A review was conducted of all neonatal ECLS patients at the neonatal intensive care nursery at Kosair Children's Hospital in Louisville, Kentucky, from May, 1985 through November, 1994 to establish a study group of infants in whom an ICH developed while on ECLS. Thirty infants who had an ICH (excluding subarachnoid hemorrhage and infarction) on ECLS were included in the study. Data were collected that included patients demographics, age at initiation of ECLS, duration of ECLS, type of ECLS support (venoarterial or venovenous), oxygenation index and last arterial blood gas before ECLS, hours of ECLS before ICH, and grade of ICH. ICH occurred in 9.9% of the neonatal patients requiring ECLS. These included 8 infants with a Grade I bleed, 1 infant with a Grade II, 4 infants with a Grade III, and 17 infants with a Grade IV. Ten of the 30 patients had sepsis as their primary diagnosis, and these infants were more likely to have an ICH while on ECLS compared to nonseptic infants (p < 0.02). The Kaplan-Meier curve showed that 50% of ICHs occurred in the first 24 hours of ECLS, 75% by 48 hours, and that 85% of ICHs occurred within 72 hours of initiation of bypass. There was no difference in timing of ICH in the septic infants compared to the nonseptic infants. The late occurring bleeds (> 72 hours) were all associated with significant neurologic changes or with multiorgan failure. It is concluded that daily head ultrasounds should be performed during the first 3 days of ECLS because most ICHs (85%) occur in the first 72 hours of cardiopulmonary bypass. In this era of cost containment, subsequent head ultrasounds should be obtained with changes in the infant's neurologic status or with the development of multiorgan failure.

Blood Gas Analysis↗
PubMedDate not supplied

Evaluation of post extracorporeal membrane oxygenation follow-up testing.

The purpose of this study was to evaluate all post extracorporeal membrane oxygenation (ECMO) tests for their ability to detect any change in the incidence of unanticipated medical problems, and their charge to the patient. The current post ECMO protocol consists of the following tests: brain stem auditory evoked response, head computed tomography, cerebral blood flow, head ultrasonography, electroencephalography, eye examination for retinopathy of prematurity, and pneumocardiography. A retrospective review was conducted for all surviving neonatal ECMO patients treated from January, 1985, to December, 1994. The results of each test were classified as either normal, having a minor abnormality, or having a major abnormality. Statistical analyses were performed on each test comparing the incidence of minor and major abnormalities to all neonates in the neonatal intensive care nursery. Two hundred ninety-six infants survived their course on ECMO, and composed the study population. There were no significant differences between the incidence of abnormal results compared with the expected values for the following tests: cerebral blood flow (p=0.13), the eye examination (p=0.54), and pneumocardiography (p=0.22). The analyses for the brain stem auditory response, head computed tomography, head ultrasonography, and electroencephalography showed higher than expected incidences of abnormal results (p < 0.01). The data also were evaluated for major abnormalities on computed tomography and head ultrasonography. Of 161 infants who had both tests performed, 11 (6.8%) had normal head ultrasonography results, yet had a major abnormality noted on computed tomography (p < 0.01). This study is the first to review the current post ECMO protocol comprehensively, and the results suggest excluding the cerebral blood flow, eye, and pneumocardiography tests. This would result in a significant savings of $1,400 without compromising patient care. In addition, comparisons of neuroradiographic studies indicate that computed tomography of the head is sensitive enough to detect all central nervous system abnormalities that were found by ultrasonography. Excluding the post ECMO head ultrasonography, an additional savings of $300 would occur. These recommended changes reflect the current post ECMO protocol at Kosair Children's Hospital.

Brain↗
PubMedDate not supplied

Complicated cannula insertions and cannula dislodgments associated with extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation therapy remains a life saving modality for neonates with cardiopulmonary disease that is unresponsive to conventional therapy. Vital to its success is the insertion and maintenance of appropriately sized vascular cannulas. Problematic insertion and accidental dislodgments can be life threatening. To determine the treatment and outcome of these complications, a survey of participating Extracorporeal Life Support Organization centers was undertaken. Venous cannulation complications (13 patients) were due to inadequate vein size or tearing during initial attempts at cannulation. Proximal and alternative site cannulation were used. Difficult arterial cannulations (seven patients) were most often due to creation of an intimal flap that was corrected by proximal cannulation of the same vessel. The 10 cases of accidental dislodgment were most often associated with changes in position. Despite copious hemorrhage in many instances, 6 of 10 patients survived with intact neurologic status. Methods for dealing with these life threatening cannula related complications are described.

Cardiovascular Diseases↗