Showing papers by "Hospital for Sick Children published in 1989"
TL;DR: The intracerebral generators of the human auditory evoked potentials were estimated using dipole source analysis of 14-channel scalp recordings and found that the response to a 400-msec toneburst presented every 0.9 sec could be explained by three major dipole sources in each temporal lobe.
Abstract: The intracerebral generators of the human auditory evoked potentials were estimated using dipole source analysis of 14-channel scalp recordings. The response to a 400-msec toneburst presented every 0.9 sec could be explained by three major dipole sources in each temporal lobe. The first was a vertically oriented dipole located on the supratemporal plane in or near the auditory koniocortex. This contributed to the scalp-recorded N1 wave at 100 msec. The second was a vertically oriented dipole source located on the supratemporal plane somewhat anterior to the first. This contributed to both the Nl and the sustained potential (SP). The third was a laterally oriented dipole source that perhaps originated in the magnopyramidal temporal field. This contributed a negative wave to the lateral scalp recordings at the latency of 145 msec. A change in the frequency of the toneburst elicited an additional negativity in the scalp-recording ---the mismatch negativity (MMN). When the frequency change was large, the mismatch negativity was composed of two distinct sources with sequential but partially overlapping activities. The earlier corresponded to the Nl dipole sources and the later to a more anteriorly located dipole with an orientation more lateral than Nl. Only the later source was active when the frequency change was small. MMN source activities peaked about 15 msec earlier in the contralateral hemisphere, while this difference was only 4 msec for the sources of the Nl.
719 citations
TL;DR: Stably introduced a human 2-5A synthetase cDNA into a human glioblastoma cell line (T98G) andConstitutive expression of the cDNA in these cells is associated with increased levels of resistance to infection by encephalomyocarditis virus.
Abstract: The interferon (IFN)-induced enzyme 2′,5′-oligoadeny late (2-5A) synthetase has been implicated in the development of antiviral activity in human and animal cells. However, its role in IFN...
135 citations
99 citations
TL;DR: The results indicate that some of the deficits associated with developmental dyslexia are amenable to treatment, and a possible reduced tendency in the present population to generalize newly acquired specific knowledge to related knowledge domains is discussed.
91 citations
TL;DR: Parenteral therapy with various copper salts, commenced either before or after neurological impairment develops, has never been convincingly shown to result in significant cessation, reversal, or prevention of the devastating neurodegenerative progression.
Abstract: Menkes’ disease (MD) is an X-linked inherited disorder of tissue copper distribution that invariably results in death with severe progressive neurodegeneration by the age of three years (Danks, 1986). Parenteral therapy with various copper salts, commenced either before or after neurological impairment develops, has never been convincingly shown to result in significant cessation, reversal, or prevention of the devastating neurodegenerative progression (Garnica, 1984).
51 citations
TL;DR: It is suggested that Down's syndrome individuals begin life with a normal complement of brain cholinergic neurons, which opens the possibility of early therapeutic intervention to prevent the development of brainCholinergic changes in patients with DS.
Abstract: We measured the activities of the cholinergic marker enzymes choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) in autopsied brains of seven infants (age range 3 months to 1 year) with Down's syndrome (DS), a disorder in which virtually all individuals will develop by middle age the neuropathological changes of Alzheimer's disease accompanied by a marked brain cholinergic reduction. When compared with age-matched controls cholinergic enzyme activity was normal in all brain regions of the individuals with infant DS with the exception of above-normal activity in the putamen (ChAT) and the occipital cortex (AChE). Our neurochemical observations suggest that DS individuals begin life with a normal complement of brain cholinergic neurons. This opens the possibility of early therapeutic intervention to prevent the development of brain cholinergic changes in patients with DS.
51 citations
TL;DR: Frog erythrocytic virus appears to acquire its envelope from lamellar membranes which surround the virus particles as seen in the electron microscope.
Abstract: Frog erythrocytic virus (FEV), one of the largest icosahedral viruses, is enveloped, measures up to 450 nm in diameter, and contains double stranded DNA. The virus is found in the cytoplasm of erythrocytes of Rana catesbeiana, Rana septentrionalis, and Rana clamitans from Algonquin Park, Ontario (Canada). Acidophilic inclusions in infected erythrocytes stained with Giemsas stain correspond to viroplasms from which FEV buds and forms aggregates of virus particles as seen in the electron microscope. Frog erythrocytic virus appears to acquire its envelope from lamellar membranes which surround the virus particles. The virus is structurally sensitive to cesium chloride, potassium tartrate and glycerol. It is also sensitive at pH 1 to 5 and a temperature of 56 C for 15 min. The virus contains at least 16 proteins which range in relative molecular mass from 19.5 to 91.0 kilodaltons (kDa), with two major proteins of 31.0 and 43.0 kDa. The viral DNA has a buoyant density of 1.690 ± 0.005 g/ml, guanine plus cytosi...
35 citations
TL;DR: Drug-induced interstitial nephritis is characterised by inflammatory lesions of the renal interstitium developed after at least 7 to 10 days of therapy, and the clinician should be aware of possible drug interactions which are likely to increase the nephrotoxic risk of a given agent.
Abstract: Scores of drugs in common clinical use are capable of inflicting various degrees of damage to the kidney. Similarly, a large number of widely employed chemicals may adversely affect renal tissue as part of their toxic potential. A xenobiotic may damage the kidney by more than one mechanism. For example, NSAIDs may cause decreased renal perfusion, interstitial nephritis, primary glomerulopathy and/or altered potassium homeostasis. A large number of drugs and chemicals inflict their damage on the renal tubular cell secondary to intracellular accumulation to concentrations substantially higher than in the plasma or in other tissues. These include aminoglycosides, mercury and carbon tetrachloride and cephaloridine. Drug-induced interstitial nephritis is characterised by inflammatory lesions of the renal interstitium developed after at least 7 to 10 days of therapy. The immunological nature of this reaction is suggested by the associated fever, maculopapular rash and arthralgia observed in some of the patients. Although eosinophilia, eosinophiluria, and raised blood IgE levels are characteristic, immunoglobulins are not deposited in renal tissue, and the basic mechanism has not been elucidated. Renal biopsy demonstrates oedema and interstitial inflammatory reaction, mainly with lymphocytes, monocytes, eosinophils and plasma cells. Less frequent, vasculitis of small vessels or granulomatous reaction may develop, leading to necrotising glomerulonephritis. The drugs most commonly causing acute interstitial nephritis are methicillin, ampicillin, cephalosporins, rifampicin (rifampin), sulphonamides, phenindione and allopurinol. Other penicillins, NSAIDs, phenytoin, thiazides and frusemide (furosemide) are less frequently associated with this syndrome. Drugs and chemicals may affect renal function by pharmacologically decreasing glomerular filtration rate and/or renal blood flow. These include the NSAIDs, radiological contrast media and cyclosporin. Normal renal function depends upon an intact glomerular apparatus. Many drugs and chemicals are capable of damaging the glomerulus, causing its increased permeability to large molecules such as proteins. Several drugs including d-penicillamine, thiopronine, captopril, pyrithioxine and methimazole, are believed to exert their damage through their sulfhydryl group which bind with high affinity to glomerular structures. A variety of xenobiotics or their metabolites may be deposited in the renal tubule causing obstruction of urine flow and a secondary damage to tubular epithelium. Sulphonamides, methotrexate and ethylene glycol are good examples.(ABSTRACT TRUNCATED AT 400 WORDS)
28 citations
TL;DR: In this paper, the authors developed a measure of temperament for preschool-age children, the Child Characteristics Questionnaire (CCQ) for 24-month-old toddlers (Lee & Bates, 1985) was modified for use at age 4.
Abstract: To develop a measure of temperament for preschool-age children, the Child Characteristics Questionnaire (CCQ) for 24-month-old toddlers (Lee & Bates, 1985) was modified for use at age 4. The modified version was called the Preschool Characteristics Questionnaire (PCQ) and was completed by 121 mothers. Maximum likelihood factor analysis of the PCQ revealed four factors—Persistent/Unstoppable, Negative Adaptation and Affect, Difficult, and Irregular—accounting for 36.1% of the total variance. Correlations between difficult temperament at age 7 months and age 4 years revealed moderate stability of the difficult temperament trait. Of the infants classified as difficult at age 7 months, 46% continued to be perceived as difficult at age 4.
23 citations
TL;DR: Thirty neonates with ileostomy patients followed-up retrospectively received a sodium substitution of at least 4-6 mmol/kg orally per day, and all patients were successfully fed orally and most of them nursed at home until closure of the ILEostomy.
Abstract: The main function of the colon is fluid and sodium conservation. In ileostomy patients these colonic functions are lacking. The consequence is excessive loss of fluid and sodium, failure to thrive, and skin excoriation around the ileostomy. Patients with ileostomies require 6-10 mmol/kg sodium per day. With ordinary feeds, infants receive 2-4 mmol/kg sodium; therefore the sodium deficit may be estimated at 4-6 mmol/kg per day. Monitoring of adequate sodium substitution is best carried out by measuring the concentration of sodium in spot urine. Levels higher than 10 mmol/1 sodium signify an adequate oral sodium intake. During the initial period of oral feeding, glucose excretion in the ileostomy fluid must be monitored, as glucose-positive ileostomy effluence necessitates additional sodium substitution in order to activate the sodium and glucose cotransport. Thirty neonates with ileostomies were followed-up retrospectively. All patients received a sodium substitution of at least 4-6 mmol/kg orally per day. The 30 patients had a total of 4769 ileostomy-days. All patients were successfully fed orally and most of them nursed at homeuntil closure of the ileostomy.
22 citations
TL;DR: The association of maternal antibodies to Ro (SS-A) from transient "neonatal" SLE to SLE in childhood is extended, and it is suggested that maternal antibody to Ro-A may be of fundamental importance in the pathogenesis of some cases of childhood SLE.
Abstract: In this study of 71 children with systemic lupus erythematosus (SLE) and 188 of their first-degree relatives, we demonstrated that the development of SLE in male children younger than age 18, and in all children younger than age 10 at the time of diagnosis, is strongly correlated with the presence of antibodies to Ro (SS-A) in the mother's serum. When the relative antibody concentration was quantified, increased quantities of antibody to Ro (SS-A) were also found in mothers of male probands and mothers of probands whose SLE was diagnosed before age 10. No similar association was found for the presence or amount of antibody to Ro (SS-A) in other first-degree relatives or for antibody to La (SS-B) or nuclear RNP in any relative. The explanation for the association of maternal anti-Ro (SS-A) antibodies and early diagnosis of SLE or male sex is not apparent. These findings extend the association of maternal antibodies to Ro (SS-A) from transient "neonatal" SLE to SLE in childhood, and suggest that maternal antibodies to Ro (SS-A) may be of fundamental importance in the pathogenesis of some cases of childhood SLE.
TL;DR: A two-year prospective study compared individual and group models of support for foster parents and showed greater foster parent satisfaction with the group model.
Abstract: A two-year prospective study compared individual and group models of support for foster parents. Results showed greater foster parent satisfaction with the group model. An independent critique identified methodological flaws that would preclude further differentiation of the models and suggested that clinical impressions and trends in favor of the group model be given credibility. Operation of the group model is described, and reasons for the differences between clinical and experimental findings are discussed.
01 Jan 1989
TL;DR: A prototypical model-based diagnostic expert system for skeletal dysplasias is discussed in the context of the competent expert systems methodology and an advanced generic architecture for second generation diagnostic systems.
Abstract: A prototypical model-based diagnostic expert system for skeletal dysplasias is discussed in the context of the competent expert systems methodology and an advanced generic architecture for second generation diagnostic systems.
TL;DR: It is shown here that certain T cell populations can be expanded by administration of particular immunoglobulins isolated from hybridomas derived from scid Ig+ mice.
Abstract: Although the scid defect is complete in the majority of young and adult mice, ~41% of those that are kept for nine months or more, develop some form of T and B cell involvement. The nature of the T cells that develop in these scid mice is described by Carroll et al. this volume. B cell involvement is characterized by the presence of large amounts of serum immunoglobulin in mice which were previously immunoglobulin negative. Mice which have high serum antibody titres have been called “leaky” and will be referred to as scid Ig+ in this text. Scid Ig+ mice have expressed µ, γ1, γ2b, γ3 and κ; so far no γ2b, α or λ production has been detected. We have isolated hybridomas from completely deficient and scid Ig+ mice. In independent fusions from scid mice no Ig producing hybridomas were obtained; however, large numbers of Ig producing hybridomas have been isolated from fusion of spleen cells of scid Ig+ mice. Analysis of the hybridomas isolated from scid Ig+ mice has revealed a restricted heterogeneity with respect to the κ light chains and the VH regions expressed in the collection of hybridomas obtained from each individual mouse. Furthermore, idiotypes appear to be shared by immunoglobulins derived from some individual scid Ig+ mice analyzed. Preliminary studies suggested that in scid Ig+ mice the defect involved in the failure to produce normal B cells is overcome on rare occasions. The pauciclonal B cells that emerge proliferate in the absence of normal auto-regulatory mechanisms perhaps being activated by auto- or environmental antigens. That both stimuli may be involved is suggested by our finding that a proportion of antibodies from these scid Ig+ mice have specificity for nuclear antigens and antigens expressed by certain strains of Enterobacter and Serratia. As suggested by previous studies there appears to be a relationship between the T and B cells that appear in scid Ig+ mice. We show here that certain T cell populations can be expanded by administration of particular immunoglobulins isolated from hybridomas derived from scid Ig+ mice.
01 Jan 1989
TL;DR: This chapter presents the criteria developed at a large Canadian pediatric hospital for the diagnosis of brain death, and the experience in reaching this diagnosis over a recent four year period.
Abstract: This chapter presents the criteria developed at a large Canadian pediatric hospital for the diagnosis of brain death, and our experience in reaching this diagnosis over a recent four year period. The historical development of Canadian guidelines is reviewed and future recommendations are presented.
TL;DR: 6PP is as good as 24 at predicting severe reflux and an adequate prediction of the degree of acid reflux in both infants and children for those with moderate reflux.
Abstract: 24 hour ambulatory pH monitoring is the “gold” standard for detecting gastro-oesophageal reflux (GOR) but requires an overnight admission. In children there are few studies of abbreviated pH monitoring suitable for day patient use. Some have suggested that in infants GOR is mostly post-prandial thus abbreviated post-prandial pH monitoring may be a suitable test for reflux. Others believe that in infants most GOR occurs when asleep. We have investigated 100 patients (20 10% reflux. Those with severe reflux (>20% 20/71) were detected in both tests. In those under 6/12, 13/20 refluxed on 24 and 12/20 on 6PP. Only 3/20 had significantly more reflux in the sleep period. The data indicates that 6PP is as good as 24 at predicting severe reflux and an adequate prediction of the degree of acid reflux in both infants and children for those with moderate reflux. GOR did not occur significantly more frequently during sleep in infants under 6/12 of age.
TL;DR: There are limitations on the use of radiolabelled antibodies for targeting isotopes to primary tumour masses, and a possible important role for antibodies in targeting therapeutic agents to minimal residual disease and diffuse tumours presenting as micro-metastasis is outlined.
Abstract: The idea of antibodies acting as magic bullets to target cytotoxic compounds selectively to specific sites in the body was introduced by Hericourt and Richet in 1895 [10] and Ehrlich in 1913 [7]. The use of hetero-antisera as a targeting medium has however, in many cases, been fraught with problems. These include difficulties in absorbing reagents to obtain sera of high specificity, and the irreproducibility of batches of antisera prepared in different animals [3, 13]. Despite this, several workers have successfully used radiolabelled polyclonal antisera for scintigraphic studies in patients with a variety of malignancies [2, 8, 16]. In addition, Order and Lenhard have used radiolabelled hetero-antisera to treat hepatocellular carcinoma and Hodgkin’s disease [15, 20]. To avoid the problem of host antibody responses changing the pharmacokinetics of the targeting agent, they used antibodies prepared in a variety of different species.