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Biomedical subjects

G Brown

Publications and source records attributed to G Brown.

At least 289 records · Page 16Linked to original sources
PubMed1991

Use of the cell saver during elective abdominal aortic aneurysm surgery--influence on transfusion with bank blood. A retrospective survey.

One hundred and two patients undergoing elective abdominal aortic aneurysm repair and admitted to ICU at RPAH in 1989/90 were studied. In forty patients a cell saver was used during the operative procedure (Group CS) while in the remaining sixty-two patients intraoperative blood loss was drained and discarded conventionally (Group NCS). Preoperative ASA grade and postoperative APACHE score were similar in these two groups. The amount of bank blood transfused intraoperatively was less in Group CS than in Group NCS (0.6 +/- 0.2 vs 3.3 +/- 0.3 units) (mean +/- SEM) (P less than 0.0001). The total amount of bank blood transfused during hospital admission was also less in Group CS (1.5 +/- 0.4 vs 4.8 +/- 0.4 units, P less than 0.0001). Of Group CS, 22 patients (55%) received no bank blood compared to two patients (3%) in Group NCS. There was no difference between the groups with respect to postoperative haemoglobin and creatinine levels. ICU stay was similar in both groups. We conclude that use of the cell saver reduces perioperative bank blood transfusion in elective abdominal aortic surgery.

Aged↗
PubMed1991

Effects of pituitary-testicular axis suppression in utero and during the early neonatal period with a long-acting luteinizing hormone-releasing hormone analog on genital development, somatic growth, and bone density in male cynomolgus monkeys in the first 6 months of life.

The specific role of late fetal and early neonatal gonadotropins and/or sex steroids on genital development, linear growth, and bone mass accretion remains unclear. To investigate this, we attempted to selectively suppress pituitary-testicular activation from midgestation through early infancy with a long-acting LHRH agonist (LHRHA), D-Trp6,Pro9-NEt-LHRH, in microspheres. The agonist was injected sc on days 72-81 in utero, on day 1 of life, and 3 months postnatally in male cynomolgus monkeys. Control animals were treated with placebo. We then examined the consequences of such an intervention in the first 6 months of life. In the LHRHA-treated animals, marked suppression of plasma testosterone and gonadotropin levels were evident in the first 3 months of life compared to control values. The mean testicular volumes of the LHRHA group were significantly lower at birth and in the first 2 months of life than those of the placebo group (P less than 0.05). However, by 4 months of age, the mean testicular volumes of the two groups were comparable. Similarly, the mean stretched phallic lengths of the LHRH approximately A group were significantly lower than those of the placebo group throughout the first 6 months of life (P less than 0.05). By contrast, LHRHA treatment had no effect on somatic growth, as mean body weights, total body lengths, and trunk lengths of the two groups were similar over the first 6 months of life. Mean bone widths and densities of the distal third of the left radius and the left midfemur were similar in the two groups at 1 and 6 months of life. We conclude that pituitary-testicular axis suppression with a long-acting LHRHA in utero and during early infancy results in markedly stunted penile and testicular growth without affecting general somatic growth and bone density of appendicular cortical bone in the cynomolgus monkey in the first 6 months of life. Thus, an intact fetal and neonatal pituitary-testicular axis is critical for normal genital growth. However, the sex steroid requirement for maintenance of bone mineral content of appendicular cortical bone may be lower than that necessary for normal genital development.

Aging↗
PubMed1991

Studies of bone marrow and leucocyte counts in peripheral blood in fetal and newborn foals.

Clinical and pathological records of 124 foals were studied. The foals were assigned to six groups; normal, premature, dysmature, bacterially infected, neonatal maladjustment syndrome and Equid herpesvirus type 1 (EHV-1) infected. Also, 6 pony fetuses were sampled via catheters in the umbilical vein and artery between 280 and 310 days gestation. Bone marrow aspiration was performed on a further 14 foals. Premature foals had significantly lower neutrophil counts than normal foals up to 5 h. Foals with bacterial infections had significantly lower neutrophil counts up to age 12 h. EHV-1 infected foals had significantly lower neutrophil counts up to age 24 h and significantly lower lymphocyte counts than all other groups up to age 12 h. Premature foals showed a higher neutrophil count and neutrophil/lymphocyte (N:L) ratio in survivors compared with non-survivors when all ages were considered, although the differences were not significant before 35 h. Discriminant analysis showed a 99% chance that the EHV-1 group could be identified from all other groups except dysmature foals, where discrimination between the two groups was about 90%. In catheterized fetuses, age-related increases in neutrophil counts and the N:L ratio occur from 280 to 310 days of gestation. In one preparation available for study leading up to parturition, the N:L ratio widened during the 3 days pre-partum. The bone marrow aspirates showed no significant changes in the myeloid:erythroid (M:E) ratio during the first 4 days post partum. The left shift (LS) index was significantly higher in foals suffering bacterial infection compared with normal or dysmature foals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Pharmacologic treatment of primary and secondary pulmonary hypertension.

A variety of diseases are associated with elevation of pressure within the pulmonary circulation. Pulmonary hypertension is considered a contributor to the morbidity and mortality associated with these conditions. An understanding of the pathophysiology and consequences of pulmonary hypertension is required when considering pharmacologic treatment. Information regarding the potential benefits and toxicities of the drug therapy for primary and secondary hypertension is necessary when considering the use of specific agents for an individual patients.

Heart Diseases↗
PubMed1990

Regression of coronary artery disease as a result of intensive lipid-lowering therapy in men with high levels of apolipoprotein B.

BACKGROUND AND METHODS: The effect of intensive lipid-lowering therapy on coronary atherosclerosis among men at high risk for cardiovascular events was assessed by quantitative arteriography. Of 146 men no more than 62 years of age who had apolipoprotein B levels greater than or equal to 125 mg per deciliter, documented coronary artery disease, and a family history of vascular disease, 120 completed the 2 1/2-year double-blind study, which included arteriography at base line and after treatment. Patients were given dietary counseling and were randomly assigned to one of three treatments: lovastatin (20 mg twice a day) and colestipol (10 g three times a day); niacin (1 g four times a day) and colestipol (10 g three times a day); or conventional therapy with placebo (or colestipol if the low-density lipoprotein [LDL] cholesterol level was elevated). RESULTS: The levels of LDL and high-density lipoprotein (HDL) cholesterol changed only slightly in the conventional-therapy group (mean changes, -7 and +5 percent, respectively), but more substantially among patients treated with lovastatin and colestipol (-46 and +15 percent) or niacin and colestipol (-32 and +43 percent). In the conventional-therapy group, 46 percent of the patients had definite lesion progression (and no regression) in at least one of nine proximal coronary segments; regression was the only change in 11 percent. By comparison, progression (as the only change) was less frequent among patients who received lovastatin and colestipol (21 percent) and those who received niacin and colestipol (25 percent), and regression was more frequent (lovastatin and colestipol, 32 percent; niacin and colestipol, 39 percent; P less than 0.005). Multivariate analysis indicated that a reduction in the level of apolipoprotein B (or LDL cholesterol) and in systolic blood pressure, and an increase in HDL cholesterol correlated independently with regression of coronary lesions. Clinical events (death, myocardial infarction, or revascularization for worsening symptoms) occurred in 10 of 52 patients assigned to conventional therapy, as compared with 3 of 46 assigned to receive lovastatin and colestipol and 2 of 48 assigned to receive niacin and colestipol (relative risk of an event during intensive treatment, 0.27; 95 percent confidence interval, 0.10 to 0.77). CONCLUSIONS: In men with coronary artery disease who were at high risk for cardiovascular events, intensive lipid-lowering therapy reduced the frequency of progression of coronary lesions, increased the frequency of regression, and reduced the incidence of cardiovascular events.

Adult↗
PubMed1990

Inositol lipids and phosphates in the regulation of the growth and differentiation of haemopoietic and other cells.

Stimulation of phosphatidylinositol 4,5-bisphosphate hydrolysis is an important signalling reaction involved in the responses of cells to some, but not all, stimuli that promote cell proliferation. Active agents in this regard include antigens activating T and B lymphocytes, angiotensin (employing a receptor encoded by the mas oncogene), bombesin and platelet-derived growth factor PDGF). However, accumulating evidence suggests that inositol lipids and phosphates also have other roles in the regulation of cell growth and differentiation. Growth factor receptors that encode tyrosine kinases (such as that for PDGF) activate a kinase that synthesises phosphatidylinositol 3-phosphate, a novel lipid, and loss of this kinase-activating function abolishes growth-promoting activity. Human interleukin-4, a lymphokine that activates B lymphocytes, appears to employ phosphatidylinositol 4,5-bisphosphate hydrolysis as a brief initial signal that is followed by a sustained rise in cyclic adenosine monophosphate (cAMP): both signals are needed for the successful induction of the surface antigen CD23. Moreover, the same inositol lipid signalling pathway as is employed by antigen-stimulated mature T lymphocytes to provoke proliferation may be redeployed in immature T cells to trigger their elimination when they encounter self-antigens. Finally, studies of HL60 promyelocytic cells have shown that these cells contain high concentrations of inositol 3,4,5,6-tetrakisphosphate, 1,3,4,5,6-pentakisphosphate and hexakisphosphate, three inositol polyphosphates that are probably formed independently of inositol lipid metabolism. When these cells are induced to differentiate either towards neutrophils (in the presence of dimethylsulphoxide) or macrophages (in phorbol myristate acetate), cessation of growth and acquisition of differentiated characteristics are accompanied by large and different changes in the concentrations of these inositol phosphates that may be characteristic of these two pathways of differentiation.

Animals↗
PubMed1990

Models of haemopoiesis.

To date, various models have been proposed to explain the diversification of haemopoietic stem cells along one of at least six pathways of differentiation. Consideration of evidence for and against particular models leads to the conclusion that a precise lineage map for the haemopoietic system is, as yet, unavailable. However, recently available cell and molecular biology techniques provide the means to resolve this problem.

Hematopoiesis↗
PubMed1990

Phorbol myristate acetate treatment of normal human myeloid blast cells promotes monopoiesis and inhibits granulopoiesis.

Fractionation of mononuclear cells from human fetal liver provides a cell population at early stages of myeloid differentiation which, when cultured, generates neutrophils and macrophages for up to a month. These studies describe the further purification of an undifferentiated myeloid blast cell population by rosette sedimentation of unwanted cells, after coating these cells with monoclonal antibodies which identify macrophages and erythroblasts. In culture, the purified blast cells generated only neutrophils and macrophages. When treated with 10 nM PMA, 62% of the purified cells were induced to differentiate towards macrophages within 48 h. PMA-induced cells acquired morphological features of macrophages and synthesized alpha-naphthyl acetate esterase. The differentiation of the remaining blast cells towards neutrophils, seen in untreated cultures, was completely inhibited by PMA, as revealed by the absence of increases in the numbers of cells expressing lactoferrin and an antigen which appears at the promyelocyte stage of differentiation. Thus, PMA effects intracellular changes which both promote monopoiesis and inhibit granulopoiesis, suggesting a reciprocal interaction between intracellular processes which regulate the capacity for the two pathways of maturation. The purified blast cell population provides a good model system for studies of molecular events which regulate the expression of macrophage characteristics.

Cell Differentiation↗
PubMed1990

Clinical evaluation of an acetaminophen meter for the rapid diagnosis of acetaminophen intoxication.

STUDY OBJECTIVES: To test the accuracy of a newly developed meter that determines serum acetaminophen concentration after a 30-second analysis of one drop of whole blood. DESIGN: Sixty-six blood samples from patients with known or suspected drug overdose were analyzed for the presence of acetaminophen. In all cases determination of serum acetaminophen concentration was performed simultaneously with the meter and by a reference laboratory. SETTING: Eligible patients were those who presented during a nine-month period to the emergency departments of two tertiary care hospitals (including a pediatric hospital). RESULTS: Thirty-one specimens had a laboratory-confirmed detectable acetaminophen concentration. The meter identified these toxic specimens in all cases; there were no false-negatives (sensitivity, 100%). Among the 35 specimens not containing acetaminophen, the meter invariably confirmed a nondetectable serum acetaminophen concentration (specificity, 100%). Acetaminophen measurements by the meter correlated strongly with laboratory determinations (r = .985, P less than .001). Repeated testing of one specimen documented the precision and reproducibility of the meter's analysis; mean coefficient of variation was .08 in measuring toxic acetaminophen concentrations. Drug coingestion had no significant effect on the accuracy of the meter. Instrument accuracy was maintained after more than 100 uses without recalibration. CONCLUSIONS: This meter identifies the possibility of rapid and accurate determinations of serum acetaminophen concentration. The instrument is ideally suited for patients with acetaminophen poisoning in whom expeditious and appropriate administration of antidotal therapy is desired.

Acetaminophen↗
PubMed1990

Detection of articular defects using magnetic resonance imaging: an experimental study.

This study evaluates magnetic resonance imaging (MRI) in the detection of surgically created articular defects in bovine knees. A total of 26 articular defects was created in 2 fresh cadaveric cows' knees. The defects created include chondromalacic grade 2 defects, chondral and osteochondral defects from 3 to 15 mm in diameter. The knee joints were repaired in a normal saline bath to exclude air in the joint prior to MR scanning. T1 weighted spin echo (SE) images and 3D gradient echo (FISP 40 degrees 3D) images were obtained. The T1 weighted SE imaging technique detected 15 defects (57.7%) compared with FISP 3D imaging technique detection of 17 defects (65.4%). The two techniques combined enable 21 of 26 defects (80.8%) to be detected. The imaging techniques used in this study were not able to detect chondromalacic defects less than 10 mm in diameter, nor chondral defects less than 5 mm in diameter. However, small osteochondral defects of 3 mm in diameter are detectable provided the depth of the defect is not less than 10 mm. The FISP 3D imaging technique alone is more sensitive in detecting chondral defects. Both imaging techniques have similarly high sensitivities in detecting osteochondral defects. The imaging time for combined T1 weighted SE and FISP 3D sequence is short (16.5 mm) and this combined technique may be useful for MR scanning of knee joints suspected to have articular defects.

Animals↗
PubMed1990

The effects of a pectin-supplemented elemental diet in a boy with short gut syndrome.

The effect of a pectin-supplemented diet in short gut syndrome was investigated in a 3-year-old boy. Nitrogen absorption was higher and stomach-to-anus transit time was prolonged during pectin supplementation of the enteral feed. Pectin supplementation had no adverse effects on electrolyte balance or glucose absorption. These data indicate that pectin supplementation of enteral feed may enhance nitrogen absorption and seems not to adversely affect absorption in short gut syndrome.

Child, Preschool↗
PubMed1990

Relationship between hopelessness and ultimate suicide: a replication with psychiatric outpatients.

A prospective study of 1,958 outpatients found that hopelessness, as measured by the Beck Hopelessness Scale, was significantly related to eventual suicide. A scale cutoff score of 9 or above identified 16 (94.2%) of the 17 patients who eventually committed suicide, thus replicating a previous study with hospitalized patients. The high-risk group identified by this cutoff score was 11 times more likely to commit suicide than the rest of the outpatients. The Beck Hopelessness Scale thus may be used as a sensitive indicator of suicide potential.

Adolescent↗
PubMed1990

Life events and the course of bipolar disorder.

The authors examined the impact of life stress on the course of bipolar disorder over a 2-year period in a group of 61 outpatients. The patients were followed prospectively with ongoing assessments of stressful life events, symptoms, levels of maintenance medication, and compliance with treatment regimens. As predicted, survival analyses indicated a significant association between life events and relapse or recurrence of the disorder. These effects could not be explained by differences in levels of medication or compliance. Further research is recommended to examine which specific subgroups of bipolar patients are most susceptible to stress.

Adult↗
PubMed1990

Consumer perspectives of direct marketing techniques and charitable contributions to healthcare institutions.

This study analyzes consumer sentiment toward the use of direct mail and telemarketing in the solicitation of donations for healthcare organizations. In addition, reasons for giving to healthcare organizations are examined. It was found that consumers have a more positive disposition toward the use of direct mail than in the use of the telephone. This study also provides an indication of healthcare's relative position to other charitable organizations.

Attitude to Health↗
PubMed1990

Construction alternatives for free-standing facilities.

Many hospitals are exploring free-standing facilities as an option for providing more efficient imaging services. Mr. Brown discusses the pros and cons of an emerging building technology, manufactured construction, in which building and site preparation are done simultaneously. He presents the criteria managers should use to make a knowledgeable decision.

Academic Medical Centers↗
PubMed1990

Clinical pharmacy workload measurement: pharmacokinetic and drug information services.

Clinical workload measurement statistics have not been completely documented or related to service characteristics. The Clinical Hospital Pharmacy Administrative Group of British Columbia measured the time required for provision of clinical pharmacokinetic and drug information services utilizing standard definitions of component activities. Pharmacists in 10 participating hospitals independently recorded the time required for the various components of these services. The data collected allows for an estimation of workload requirements by similar institutions and allows for comparison of the impact of differences in methods of organization of the services on workload measurement.

British Columbia↗