Structure and function studies of plant cell wall polysaccharides.
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Carbohydrate Sequence↗
Biomedical subjects
M O'Neill
Publications and source records attributed to M O'Neill.
Adsorption filtration of leukocyte-reduced single donor platelet units.
The effect of adsorption filtration of leukocyte-reduced single donor platelet (SDP) units collected on a CS-3000+ with a TNX chamber was compared to filtration of SDP units prepared via an isoradial chamber. The leukocyte enumeration technique employed a Nageotte chamber and had a nominal lower detection limit of 0.05 leukocytes/microliter (if no cells were seen, the concentration was recorded as 0.01 microliter). Although the prefiltration leukocyte content of the TNX units was unexpectedly low (2.4 +/- 2.8 x 10(4) per unit), filtration reduced the leukocyte content further to no greater than 1.7 +/- 0.07 x 10(3) (p < 0.05). (The full extent of the leukocyte removal could not be assessed as no leukocytes were seen in counting any of the 20 filtered TNX units). The 20 isoradial (control) SDP units achieved similar leukocyte depletion, with a postfiltration leukocyte content of 2.7 +/- 2.5 x 10(3) (p > 0.05, compared to filtered TNX units). Thus while significant leukocyte reduction occurred with adsorption filtration of both control and leukocyte-depleted SDP units, comparison of the relative degree of reduction awaits application of more sensitive leukocyte counting techniques. This study documented, however, that additional leukocyte reduction can be obtained by applying adsorption filtration to SDP units with an already low leukocyte content.
Adsorption↗
Exercise and pregnancy: a review.
The effects of pregnancy on the maternal cardiorespiratory system include increases in oxygen consumption, cardiac output, heart rate, stroke volume, and plasma volume. The increase in oxygen reserve seen in early pregnancy is reduced later, suggesting that maternal exercise may present a greater physiologic stress in the third trimester. Evidence suggests that weight-bearing exercise produces a greater decrease in oxygen reserve than nonweight-bearing exercise. Furthermore, to maintain a heart rate below 140 beats per minute during pregnancy, the intensity of weight-bearing exercise must be reduced. Nonweight-bearing, water-based exercise results in smaller fetal heart rate changes and a lower maternal heart rate than the same exercise performed on land. Exercising in the supine position in late pregnancy has raised concerns because cardiac output in the supine position is lower than in the lateral position at rest, presumably because the gravid uterus partially obstructs the inferior vena cava. Sustained exercise produces a training effect on the mother, although reported associations between this effect and the experience of labor are not consistent. Short-term changes in fetal heart rate provide circumstantial evidence that physical activity can influence the fetus. Acute effects of exercise that can potentially affect the fetus include hyperthermia, changes in uteroplacental flow, reduced levels of maternal glucose, and increased uterine contractions. Moderate to high levels of sustained maternal exercise have been associated with reduced birthweight. Much research remains to be done on the effects of specific exercise regimens during pregnancy, the effects on previously sedentary women, and the long-term health consequences to the offspring of women who perform vigorous exercise during pregnancy.
Birth Weight↗
Exciton radiative decay and homogeneous broadening in CdTe/Cd0.85Mn0.15Te multiple quantum wells.
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Journal Article↗
Cardiac sympathetic nerve stimulation enhances cardiovascular performance during hyperkalaemia in the anaesthetized pig.
A rapid increase in arterial plasma potassium concentration to values seen during intense exercise depresses cardiac function at rest. Increasing the cardiac concentration of noradrenaline by right-sided sympathetic stimulation in eleven anaesthetized pigs significantly augmented cardiovascular performance during hyperkalaemia, while electrical pacing of the right atrium at equivalent rates to sympathetic stimulation afforded no protection against the deleterious effects of hyperkalaemia. We conclude that the inotropic effect of sympathetic activation may be important in sustaining cardiac function during exercise-induced hyperkalaemia.
Animals↗
Diagnosis of vertical human immunodeficiency virus type 1 infection by whole blood culture.
The qualitative and quantitative performance of a human immunodeficiency virus type 1 (HIV-1) whole blood culture method was assessed for use in the diagnosis of vertical HIV-1 infection. This method requires < 1 mL of whole blood and allows for the quantification of blood virus load. HIV-1 was isolated from 36 (95%) of 38 whole blood specimens from 27 HIV-1-infected children compared with 0 of 16 whole blood specimens from 16 uninfected children. HIV-1 titers were significantly higher in severely symptomatic children (2450 TCID/mL) than in less symptomatic children (179 TCID/mL). This simple quantitative culture assay may be useful for the early diagnosis of vertical HIV-1 infection, the assessment of blood virus load, and the evaluation of antiretroviral therapies.
Acquired Immunodeficiency Syndrome↗
Schizophrenics and social judgement. Why do schizophrenics get it wrong?
Videotaped social interactions were shown to a population of schizophrenics and controls who were asked to comment on the emotional state of the principal protagonist. Their free responses were subjected to a content analysis to examine which of three possible explanations of known schizophrenic inaccuracies on this task were responsible: formal thought disorder, selective avoidance of psychological factors, or perceptual/attentional deficits. Neither selective avoidance nor marked thought disorder were found to explain these errors. The schizophrenics as a group rated much the same, irrespective of clinical profile. Their judgements of personality were less clear-cut than the controls.
Adult↗
Community participation in Quebec's health system: a strategy to curtail community empowerment?
Since the beginning of the 1970s, the province of Quebec has undergone a major reform of its health and social services system. Following this reform, the state has become a major protagonist, and the participation of the population is a built-in element in the system, guaranteed by law. Now, about 20 years later, there is a major effort to reorganize health services, in the wake of a "dewelfarization" mood that has reached Canada and Quebec. This article reviews the successes and pitfalls of public participation in Quebec's health system, presents the way in which participation is dealt with in current reform proposals, and draws lessons for people in many countries who have recently been encouraged to jump onto the bandwagon of participation as a strategy to promote the health of populations.
Community Health Centers↗
Enamel microabrasion: a microscopic evaluation of the "abrosion effect".
Enamel surfaces have been found to acquire a glasslike luster and an exceptionally smooth texture following enamel microabrasion procedures. A commercially available enamel microabrasion compound containing abrasive particles and a mild concentration of hydrochloric acid, when applied by rotary compression, simultaneously abrades and erodes (abrosion) the enamel surface. Human enamel surfaces were evaluated microscopically after routine enamel microabrasion procedures. The results show distinct evidence of enamel surface changes that have been described as the abrosion effect.
Complex Mixtures↗
Structural analysis of the glycoprotein allergen Art v II from the pollen of mugwort (Artemisia vulgaris L.).
The glycoprotein allergen Art v II, from the pollen of mugwort (Artemisia vulgaris L.) was treated with peptide:N-glycosidase F (PNGase F) to release asparagine-linked oligosaccharides. The oligosaccharides were isolated by gel permeation chromatography and their structures determined by 500-MHz 1H NMR spectroscopy, fast atom bombardment-mass spectrometry, and high-pH anion-exchange chromatography. The high-mannose oligosaccharides Man5GlcNAc2, Man6GlcNAc2, Man7GlcNAc2, Man8GlcNAc2, and Man9GlcNAc2 were present in the ratios 2:49:19:24:6 and accounted for all the asparagine-linked oligosaccharides released from Art v II by PNGase F. The NH2-terminal amino acid sequences of Art v II and of four peptides generated by cyanogen bromide (CNBr) cleavage of deglycosylated Art v II were determined. The first 30 amino acid residues of Art v II did not contain any potential N-glycosylation sites. One potential N-glycosylation site was identified in one of the CNBr fragments. The native protein conformation was shown by enzyme-linked immunosorbent assay inhibition assays to be essential for the binding of rabbit IgG to Art v II and for the binding of human IgE to the major IgE-binding epitope(s) in this allergen. At least one minor IgE-binding epitope still bound IgE after denaturation of the allergen. Removal of the high-mannose chains from denatured Art v II had no significant effect on the binding of human IgE to the minor IgE-binding epitope(s).
Allergens↗
Pulmonary hemorrhage and necrotizing glomerulonephritis without glomerular immune deposits: report of two cases.
Two children with a syndrome of pulmonary hemorrhage and necrotizing, nonimmune glomerulonephritis are reported. A boy and girl, both of East Indian descent, developed recurrent lung infiltrates from the age of 3 months and 2 years, respectively. Both subsequently presented with pulmonary hemorrhage, fever, arthritis, hematuria, and nephrotic range proteinuria at 1.5 and 6 years of age, respectively. Renal biopsy in each case showed acute, severe, focal and segmental, necrotizing and crescentic glomerulonephritis without immune deposits. Subsequent renal biopsies revealed severe glomerular and tubulointerstitial scarring. No vasculitis or granulomas were seen on renal, skin, or lung biopsies. Antineutrophil cytoplasmic antibodies (ANCA) were not detected in sera taken 1.5 years in the boy and 3.5 years in the girl after the onset of renal disease. The boy was treated with prednisone, azathioprine, and plasmapheresis, but developed progressive renal impairment and commenced dialysis within 4 years. Subsequent to renal transplantation, he developed an immunoblastic lymphoma and died. The girl was treated initially with prednisone and later with cyclophosphamide. After 4 years, she had a normal glomerular filtration rate (GFR). While necrotizing nonimmune glomerulonephritis associated with pulmonary hemorrhage is rare, and cases are characteristically difficult to classify because of many overlapping features, it is possible that these children had a unique illness.
Child↗
Hurler's disease with diastematomyelia.
A case of Hurler's disease is reported in a child with a gibbous deformity of the lumbar vertebrae L1/L2 and a localized diastematomyelia of the spinal cord at L1/L3. The association of an enzyme disorder affecting connective tissue with spinal cord dysraphism has not been reported before, and may be fortuitous. However, as each condition is rare, the occurrence of both gibbous deformity due to Hurler's and diastematomyelia in the same child, makes it unlikely to be a chance association. We suggest that defective neurulation in this case may be related to mesodermal damage associated with mucopolysaccharidosis.
Brain↗
Familial infantile oesophageal achalasia.
Oesophageal achalasia is uncommon in children and in its familial form it is a rarity. The presentation and management of two male siblings who presented with oesophageal achalasia as infants are reported. A high degree of consanguinity in the parents of the children existed, suggesting autosomal recessive transmission.
Esophageal Achalasia↗
Effects of experimental context, demand characteristics, and situational cues: new data.
When in 1964 stress induced by Restricted Environmental Stimulation (REST) was publicized, Orne and Scheibe showed "sensory deprivation" effects could be produced merely by manipulating contextual cues. Since REST is now widely regarded as beneficial, it seemed appropriate to reexamine these early findings. Stringently replicating Orne and Scheibe's procedures, 10 subjects were exposed to conditions designed to generate expected REST effects. Conditions for 10 controls suggested that nothing was expected to happen. Analyses did not confirm earlier findings as no significant difference was found between experimental and control groups on any measure. A postexperimental inquiry identified positive attitudes toward REST. The specific experimental context, demand characteristics, and situational cues did not elicit responses inconsistent with the general sociopsychological context. Researchers are cautioned about attributing causality to contextual cues because context exists merely at a correlative level with data collection.
Adaptation, Psychological↗
Prevention of hypothyroidism related to mantle irradiation for Hodgkin's disease: preparative phantom study.
To decrease the incidence of hypothyroidism related to mantle irradiation for Hodgkin's disease, we initiated a study designed to protect the thyroid gland using a phantom. A thyroid phantom was filled with technetium-99m. The thyroid phantom was placed inside of its corresponding anterior neck position in a whole body phantom. An anterior scintiscan of the head and neck region demonstrated the radioactivity in the simulated thyroid. A mantle port included a focused block that would shield the thyroid from the anterior port. The phantom was exposed (4 MeV) to 180 cGy (AP-PA) at midplane with lithium fluoride dosimeters in the position of the thyroid. The thyroid received an average of 12 cGy from the anterior field and 48 cGy from the posterior field for a total of 60 cGy per treatment or 30% of the prescribed dose. A complete mantle field course of radiation of 4000 cGy would lead to a thyroid dose of 1200 cGy at a daily fractional dose of 60 cGy. We elected not to block the thyroid from the posterior field to prevent shielding and potential underdosage of involved nodal sites. The present study suggests a method of safe and effective thyroid shielding which needs to be tested clinically to determine whether it would reduce the incidence of chemical and clinical hypothyroidism or simply extend the period until occurrence.
Hodgkin Disease↗
A century of home parenteral nutrition for Crohn's disease.
During an 11-year period, 41 patients with Crohn's disease were placed on home parenteral nutrition (HPN) for a mean of 1,083 days (range: 33 to 3,258 days). Data were retrospectively analyzed to determine whether HPN had an effect on the course of their disease, i.e., on the number of operative procedures performed and the intensity of required medical therapy. Data represented information obtained during a total of 121 patient-years of HPN for Crohn's disease. The main indications for HPN were short bowel syndrome (66%) and high stoma output. Twenty-four of 41 patients (59%) underwent surgery for Crohn's disease during the course of HPN. There was no significant difference between the number of procedures performed per patient per year of Crohn's disease during pre-HPN and HPN periods (p greater than 0.25). Although there was no significant change in body weight, both serum albumin and transferrin levels increased during HPN (p less than 0.01 and p less than 0.01, respectively). Twenty-nine percent of patients were taking prednisone while on HPN, compared with 54% of patients during the pre-HPN period (p less than 0.01). HPN appeared to result in a significant improvement in the numerically assessed quality of life. During the HPN period, 24 patients had 1 or more HPN-related complications that required 1 to 13 hospital admissions (mean: 1.8). These complications included catheter sepsis in 19 patients, blocked or damaged catheters in 15 patients, and dehydration and/or electrolyte imbalance in 5 patients. Eight patients died, with 7% of deaths secondary to catheter-related sepsis. Although permanent HPN is associated with an identifiable morbidity and mortality and is not associated with a reduction in the frequency of surgery for Crohn's disease, benefits include a decrease in the intensity of medical therapy, an improvement in patients' nutritional state, and a significant perceived improvement in patients' quality of life. Without HPN, we believe all patients would have died secondary to malnutrition and/or dehydration.
Adult↗
The value of CT scans for children with headaches.
We studied the value of CT scans for all children referred because of headache to one secondary and one tertiary pediatric centre during a 1 year period. Of 117 children who were seen by the Pediatric Neurology Service, at the I.W.K. Children's Hospital, 4 had CT scans and only 1 of these was abnormal. The consultant Pediatrician saw 40 children because of headache. CT scans were done on 3 of these patients and all were normal. None of the children who had a clinical assessment alone had unrecognized neurological disease during 20 months of follow-up. Therefore only 1 of 157 children had significant intracranial pathology. We conclude that CT scans have a limited role in the management of children with headache.
Adolescent↗
Myocyte structure, function, and calcium kinetics in the cardiomyopathic hamster heart.
The hereditary cardiomyopathic strain of the Syrian hamster has been studied extensively as a model of cardiomyopathy and heart failure. However, the primary defect underlying the cascade of events leading to heart failure has not been identified. In the present study, isolated cardiac cells were obtained for study from 8-mo-old cardiomyopathic (Bio 14.6) and age-matched normal hamsters (F1B). We examined the relationships among structure, contractile function, and calcium kinetics in these isolated cardiomyocytes. The cardiomyopathic myocytes were wider and longer than controls, and myopathic cells were less calcium tolerant. The sarcoplasmic reticulum and T-tubule systems from myopathic hearts were more abundant as determined by electron microscopy. The amplitude and velocity of contraction was decreased in cardiomyopathic cells, whereas diastolic relaxation velocity was not different between the two groups. The size of the rapidly exchangeable calcium pool determined by 45Ca2+ uptake was significantly increased in cardiomyopathic myocytes. Time-averaged cytosolic Ca2+ in these cells (472 +/- 60 nM) was significantly higher than control (260 +/- 15 nM) as measured by the fura-2 fluorescence ratio. When extracellular Ca2+ ([Ca2+]o) was increased to greater than 1.2 mM, the resulting increase in intracellular calcium concentration was less than that in normal control cells. The corresponding [Ca2+]o-induced increase in amplitude of cell motion was significantly attenuated in the cardiomyopathic cells compared with normal control myocytes. We conclude that distinct abnormalities of contractile function and calcium homeostasis can be identified in single cells isolated from cardiomyopathic hamster hearts.
Animals↗