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Biomedical subjects

J Brown

Publications and source records attributed to J Brown.

At least 721 records · Page 40Linked to original sources
PubMed1990

Effects of standard and variant strains of infectious bursal disease virus on infections of chickens.

T-cell-mediated and humoral immune responses were measured in chickens infected with standard and variant strains of infectious bursal disease virus. One-day-old and 3-week-old chickens were infected with these viruses and then given sheep RBC, killed Brucella abortus strain 19, and Newcastle disease virus. Appropriate serologic tests were used to monitor the primary and secondary responses to the antigens. Lymphoblast transformation assays were performed weekly. The response to the infectious bursal disease virus was determined by virus neutralization tests, microscopic examination of bursas, and bursal to body weight ratios. One-day-old chickens had T-cell-mediated and humoral immune suppression with both strains of virus, compared with controls. The lymphoblast transformation responses indicated that the variant strain was significantly (P less than 0.05) more suppressive than the standard strain. Three-week-old chickens had humoral immune suppression with the standard strain, but not with the variant strain. The lymphoblast transformation response was transiently suppressed at this age by the variant strain only. During the first week of infection, 1-day-old and 3-week-old chickens had lower neutralizing antibody titers to the variant strain than to the standard strain.

Age Factors↗
PubMed1990

Continuous multiple location body temperature measurement of infants.

This study was done to evaluate the most suitable location of skin temperature sensors to enable long term temperature measurements of infants. A high accuracy eight channel temperature monitor was developed. Linear semiconductor sensor probes were constructed in association with this. System accuracy and stability were tested. Preliminary clinical studies have shown considerable variation from the core temperature for all surface measurement locations.

Body Temperature↗
PubMed1990

Computer polygraphic system for infants at risk for sudden infant death syndrome (SIDS).

We have designed and developed a suite of equipment for polygraphic assessment of infants thought to be at risk for Sudden Infant Death Syndrome. A range of commercially available and custom made instrumentation is used to monitor cardio-respiratory function and thermal activity. The PC based system records continuous overnight trends and is able to detect apnoea, bradycardia, tachycardia, oxygen desaturation and other significant clinical events, producing summary data and graphs at the conclusion of the monitoring. The system is fully interactive and adaptable to various clinical and research requirements.

Computer Graphics↗
PubMed1990

From basic concepts to clinical reality. Unresolved issues in the diagnosis of dependence.

This chapter discusses clinical and conceptual issues pertaining to the diagnosis of alcohol and drug dependence. Emphasis is given to the difficulties involved in moving from diagnostic concepts, such as those contained in the major psychiatric classification systems, to the clinical situation where diagnostic decisions are made. To illustrate how diagnostic concepts approximate clinical reality, a set of case histories is used to organize a discussion of unresolved issues in the diagnosis of dependence. These issues include the putative syndrome nature of dependence, the problem of diagnosing polysubstance use, the primary-secondary distinction, the presence of other psychopathology, and the use of multiaxial evaluation.

Adult↗
PubMed1989

Characterization of cell lines derived from a multiply aneuploid human bladder transitional-cell carcinoma, UCRU-BL-13.

A series of cultured cell lines (designated UCRU-BL-13) has been established from different serial passages of a multiply aneuploid human bladder transitional-cell carcinoma xenografted in nude mice. Serial passage of the xenografts in vivo and of the cell lines in vitro was accompanied by shifts in the tumor ploidy, with dominance of different major peaks. Despite this, the expression of tumor markers remained constant, and consistent chromosomal markers were observed both in the 8th xenograft passage and in a subline in tissue culture established over a year apart. Chromosomal numbers reflected the predominant aneuploid peaks observed; consistent numerical and structural changes included a marker derived from chromosome 1, 8p-, -10, 11q+, and 17q+. The cell line derived from the initial xenograft comprised a mixture of transitional, adenocarcinoma and squamous carcinoma cells in early passage, but adenocarcinoma cells were absent from later passages. The lines expressed the B-blood-group antigen, histocompatibility antigens, receptors for transferrin and EGF, and reacted with a series of monoclonal antibodies (MAbs) directed to malignant human epithelial cell lines. These lines provide a model for studying the evolution of tumor heterogeneity and drug resistance in bladder carcinoma exhibiting multiple aneuploidy.

Aneuploidy↗
PubMed1989

Human atrial natriuretic factor (ANF). Characterisation of a monoclonal antibody panel and its use in radioimmunoassay.

The production of nine monoclonal antibodies to human atrial natriuretic factor (ANF 1-28) is described. All possible combinations of two antibodies failed to reveal any which could simultaneously bind ANF. Studies with ANF analogues and the antibodies having the three highest affinity values (KD = 5, 25 and 21 pM) indicated that the antibodies are directed to the central portion of the antigen molecule. The highest affinity antibody was able to replace polyclonal antisera in the radioimmunoassay of ANF in extracts of plasma.

Antibodies, Monoclonal↗
PubMed1989

Centrally acting alpha-2 agonists, peripherally acting adrenergic-blocking drugs, and direct vasodilators in the treatment of mild and moderate essential hypertension.

The experience with three groups of antihypertensive agents in a large hypertension clinic serving a black patient population is reported. A retrospective review of clinic records was undertaken to determine the efficacy and adverse effects of the centrally acting adrenergic agonists methyldopa and clonidine, the alpha-1 antagonist prazosin, and the direct vasodilator hydralazine in patients with mild and moderate hypertension. Treatment with methyldopa, clonidine, or prazosin, usually in combination with a diuretic produced a 30 to 38 mmHg decrease in systolic blood pressure, and a 24 to 28 mmHg reduction in diastolic blood pressure. Similar declines in blood pressure levels occurred when hydralazine was used with an alpha-2 adrenergic agonist or beta-adrenoceptor blocking agent. Evidence of clinical efficacy, defined as a decrease in systolic blood pressure to below 140 mmHg and in diastolic blood pressure to below 90 mmHg, was observed in 80% or more of the patients. An 88% efficacy rate was seen with methyldopa. Effective doses of the drugs varied considerably; most patients, however, responded at a dose close to the average dose for each agent. The most serious adverse effect observed was elevation of hepatic enzyme levels in patients receiving methyldopa, which necessitated withdrawal of the drug. Two patients treated with 0.4 mg clonidine twice a day experienced "rebound" hypertension when the drug was abruptly discontinued. Overall, good clinical efficacy and patient acceptance were found with these three groups of antihypertensive agents.

Adult↗
PubMed1989

Leukocyte function in Pelger-Huët anomaly of dogs.

Leukocyte function was evaluated in five dogs with Pelger-Huët (P-H) anomaly and in five control dogs. No significant differences were found between groups in neutrophil adherence, random movement, chemotaxis, phagocytosis, or bacterial killing of Staphylococcus intermedius. Neutrophils migrated rapidly into inflammatory sites where progressive nuclear lobulation was noted over time. Antibody titers to exogenous antigens were similar in the P-H and control groups indicating B- and T-lymphocyte cooperation in humoral immunity. Lymphocyte blastogenesis to phytohemagglutinin also was similar in both groups suggesting the presence of a responsive T-lymphocyte population. These findings indicate that no apparent predisposition to infection or immunodeficiency exists in dogs with P-H anomaly.

Animals↗
PubMed1989

Use of maximal expiratory flows to evaluate central airways obstruction in infants.

Partial expiratory flow-volume (PEFV) curves obtained by the rapid compression technique were employed to assess airway function in three infants with three different lesions of the central airways (vascular ring, congenital tracheal stenosis, subglottic polyp). Preoperatively, all three demonstrated severe flow limitation with a relatively constant forced expiratory flow over the tidal volume range. Postoperatively the PEFV curves changed to a normal convex shape, and the maximal expiratory flows at functional residual capacity (VmaxFRC) returned to normal. The PEFV curve adds to our physiologic assessment of the severity of the central airway obstruction in infants and to the efficacy of our therapeutic intervention.

Airway Obstruction↗
PubMed1989

Clinical and hemodynamic course of infants and children with anomalous left coronary artery.

The clinical history of all 17 patients with anomalous left coronary artery presenting over the last 20 years was studied, with special emphasis on those who underwent reimplantation of the anomalous coronary artery into the aorta, a procedure that became our "treatment of choice" during this period. These patients were also evaluated for ventricular performance, residual mitral regurgitation, and wall integrity. Early in our experience with reimplantation, two patients died while we waited for them to achieve a more favorable size for surgery. Eight of nine survived reimplantation; three of these were under 1 year of age when operated upon. One of these eight patients has required additional mitral valvuloplasty, but all are doing well clinically up to 12 years after operation. Preoperative left ventricular ejection fraction of 0.37 +/- 0.16 increased to 0.67 +/- 0.07 (p less than 0.001) by 1 year after surgery, despite ventricular wall abnormalities in four patients. Thus reimplantation of the anomalous left coronary artery should be undertaken upon diagnosis, since surgery can be performed successfully in infancy, with resultant improvement in ventricular function and an adequate clinical condition for at least 12 years.

Adolescent↗
PubMed1989

Simple procedures for preparing putative toxic metabolites of pyrrolizidine alkaloids.

New procedures are described for converting unsaturated pyrrolizidine alkaloids to chemically reactive pyrrolic esters (dehydro-alkaloids), which are probable primary toxic metabolites formed from these alkaloids in vivo. Preparations of dehydro-necines, including dehydroretronecine (DHR) are also described. Dehydrocrotanecine, and four new dehydro-alkaloids, are described for the first time. The methods give superior yields to earlier procedures, do not require a high degree of chemical expertise, and are particularly suitable for making small amounts of compounds for toxicological experiments.

Chemical Phenomena↗
PubMed1989

Lymphocyte reactivity to mitogens and natural killer cell activity in crossbred swine during the reproductive cycle.

The effect of pregnancy and lactation on the cell-mediated immune response of first litter gilts was assessed using the response of circulating lymphocytes to in vitro mitogen stimulation and the cytotoxic activity of the circulating natural killer (NK) cells. Groups of gilts were sampled during the first, second and third trimester of gestation, weekly during lactation, at weaning and estrus following weaning of the piglets. No significant differences were found in the response of the cells from any of the groups to phytohemagglutinin A or concanavalin A stimulation. The natural killer cell activity, measured as cytotoxicity, decreased during gestation reaching a low point during the second and third week of lactation.

Animals↗
PubMed1989

Two-year comparative trial on the immunogenicity and adverse effects of purified chick embryo cell rabies vaccine for pre-exposure immunization.

The human diploid cell rabies vaccine (HDCV) has been shown to be highly immunogenic when used for pre-exposure immunization. However, the high cost of the product and the adverse reactions seen following booster doses of HDCV have limited its use. A purified chick embryo cell (PCEC) rabies vaccine was compared with the HDCV by two routes of administration for reactogenicity, antibody response, duration of antibody, and anamestic response to boosters over a 2 year period. The study showed that the two vaccines were comparable in their immunogenicity and reactogenicity after initial three dose series. No adverse reactions were noted following the 2 year booster with PCEC. The PCEC can be produced at less than one-half the cost of the HDCV.

Adult↗
PubMed1989

Antimyosin imaging in acute transmural myocardial infarctions: results of a multicenter clinical trial.

Murine monoclonal antimyosin antibody has been shown experimentally to bind selectively to irreversibly damaged myocytes. To evaluate the safety and efficacy of monoclonal antimyosin for identifying acute transmural infarction, 50 patients with acute Q wave myocardial infarction were entered into a phase I/II multicenter trial involving three clinical sites. Indium-111 antimyosin was prepared from an instant kit formulation containing 0.5 mg of diethylene triamine pentaacetic acid (DTPA)-coupled Fab fragment (R11D10) and 1.2 to 2.4 mCi of indium-111. Average labeling efficiency was 92%. Antimyosin was injected 27 +/- 16 h after the onset of chest pain. Planar or tomographic imaging was performed 27 +/- 9 h after injection in all patients, and repeat imaging was done 24 h later in 39 patients. Of the 50 patients entered, 46 showed myocardial uptake of antimyosin (sensitivity 92%). Thirty-one of 39 planar scans performed at 24 h were diagnostic; 8 showed persistent blood pool activity that cleared by 48 h. Focal myocardial uptake of antimyosin corresponded to electrocardiographic infarct localization. No patient had an adverse reaction to antimyosin. In addition, 125 serum samples, including 21 collected greater than 42 days after injection, were tested for human antimouse antibodies, and all samples were assessed as having undetectable titers. Intensity of antimyosin uptake was correlated with infarct location and the presence or absence of collateral vessels. There was a significant correlation between faint uptake and inferoposterior infarct location. In 21 patients who had coronary angiography close to the time of antimyosin injection, there was a significant correlation between faint tracer uptake and closed infarct-related vessel with absent collateral flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

In vivo assessment of 111In-labeled hematoporphyrin derivative in breast tumor-bearing animals.

The biological behavior of 111In-labeled HPD has been investigated in tumor-bearing animals. Mice mammary adenocarcinomas and 7,12-dimethylbenz(a)anthracine induced breast tumors in Sprague-Dawley female rats were clearly visualized by 111In-HPD nuclear scintigraphy. Optimal scans were obtained after a 48 h delay. In normal and tumor-bearing animals, the highest uptake of 111In-HPD 72 h post-injection was found in the liver, the spleen and the kidneys. Depending on the size and the extent of necrosis, the uptake of 111In-HPD by malignant breast tumors varied from 2.5% injected dose (ID) (range 0.14-5.3% ID) in mice to 1% (range 0.22-8.1% ID) in rats. Benign breast tumor uptake of 111In-HPD was less than 1% ID. No significant amount of the radiopharmaceutical was found in pulmonary abscesses and abdominal cysts (less than 0.1% ID). Scintigrams of these infectious or inflammatory lesions were normal. Malignant tumor to blood, heart and lung ratios averaged 50:1, 10:1 and 3:1 respectively. Tumor to brain ratio ranged from 72 to 444:1.

9,10-Dimethyl-1,2-benzanthracene↗