Showing papers by "Hospital for Sick Children published in 1979"

Artificial beta cell

Abstract: An artificial beta cell regulates blood glucose concentration in a subject by continuously analyzing blood from the patient and deriving a computer output signal to drive a pump which infuses insulin at a rate corresponding to the signal. A value of blood glucose concentration from the analyzed blood is used by a computer to determine a rate of change of this concentration which in turn is used to derive a projected blood glucose level. A sigmoidal relationship between the projected blood glucose concentration and the rate of infusion is used to determine the actual rate of infusion required and hence an output signal is fed to the pump to create this actual rate of insulin infusion.

Mutations affecting immunoglobulin light chain secretion by myeloma cells. I. Functional analysis by cell fusion.

Abstract: Two clones of MOPC 315 cells have been selected which synthesize but do not secrete Ig lambda light chains. These clones were analyzed by fusion with a cell line synthesizing and secreting kappa chains. Conditions were established for recovery at high frequency (approximately 10−3) of spontaneously fused, viable hybrid cells. The resulting hybrid cell lines synthesized both kappa and lambda chains but secreted only kappa chains. Hybrid cells produced by fusion of a lambda-secreting clone of MOPC 315 with the kappa-secreting cell line were also isolated and shown to synthesize and secrete both kappa and lambda chains. These results suggest that the nonsecretion of lambda chains was not due to a defect in the secretion mechanism of the variant cells. A more likely alternative is that the lambda chains in the variant cell lines were structurally altered to a form which could not be secreted.

Effects of methylphenidate (Ritalin) on selective attention in hyperactive children.

Abstract: This study investigated the effect of methylphenidate (Ritalin) on the selective attention of hyperactive children designated as favorable or adverse responders to stimulant medication Using a type II incidental learning paradigm, it was found that children in the drug condition recalled more central and less incidental stimuli than those children in the placebo condition While no differential effects on recall were found for responder type, methylphenidate did affect the spontaneous overt labeling of central stimuli by the favorable responder group Results were interpreted in terms of the role of methylphenidate in narrowing the focus of attention Implications for the classification of hyperactive children as favorable and adverse responders were also discussed

Purine Nucleoside Phosphorylase Deficiency

Abstract: The biochemical features of two families with purine nucleoside phosphorylase deficiency are compared. Laboratory studies and an evaluation of kinetic and physical properties of erythrocyte purine nucleoside phosphorylase give evidence that a) the degree of abnormality in uric acid and nucleoside concentrations in plasma and urine reflect the severity of the enzymatic deficiency and b) structural alterations of the mutant enzymes result from structural gene mutations and demonstrate genetic heterogeneity in the disease purine nucleoside phosphorylase deficiency.

Measurement of anaesthetic gas concentration

Abstract: The invention provides a device capable of monitoring the concentration of anaesthetic gas in a breathing mixture being delivered to a patient to cause narcosis and consists essentially of an electronic transducer which provides an output signal proportional to the concentration of anaesthetic gas in a breathing mixture. The transducer includes a sensor having first and second electrical conductors positioned in proximity to one another and defining a space between the conductors. A substantially non-conductive material fills the space between the conductors and has a molecular structure which permits the absorption of the anaesthetic gas thereby causing variations in the electrical characteristics of the sensor. An electrical circuit is provided which is coupled to the sensor to provide the output signal which is proportional to the variations in the electrical characteristics of the sensor.

Vitamin E deficiency and seizures in animals and man.

Abstract: Study of 100 children with grand mal convulsive disorders and 100 medically healthy children of matching age showed significantly lower plasma levels of vitamin E in the former (means 632.2 +/- 17.3 and 822.5 +/- 21.8 micrograms/dl respectively; p less than 0.001). This finding accords with the ability to prevent seizures in rodents by giving alpha-tocopherol before exposing them to a convulsion-inducing environment.

Partial trisomy 20 confirmed by gene dosage studies

Abstract: We describe a female infant with multiple congenital anomalies and mental retardation, pre- and postnatal growth failure, microcephaly, unusual facial appearance, and minor skeletal anomalies, all very suggestive of the partial trisomy 20(p) syndrome. Although she was born to karyotypically normal parents, she had an extra small metacentric chromosome. Analysis of metaphase and prometaphase chromosomes by GTG banding and Giemsa 11 staining showed that the extra chromosome was a number 20 with a deletion of the distal end of the long arm. Gene dose studies of adenosine deaminase (ADA) and inosine triphosphatase (ITP) supported the cytogenetic interpretation.

Aphasic Dissolution and Language Acquisition

Abstract: Publisher Summary Both children and aphasics show incomplete inflectional rosters: they tend to use base lexical forms and often miss the bound inflectional morphemes that indicate person, number, or tense. The linguistic situations in which some of the morphemes are needed are not present in the beginning stages of acquisition; they only gradually become identifiable in child speech. Aphasics, by contrast, possess all the contexts, although they may not use them with the same frequency as the normal subject. Some of the agrammatic quality of child speech reflects not so much the loss of a particular morpheme as the absence of the context in which the morpheme might occur. This disorder is different from that of the aphasic. Aphasics are more likely than children to respond with a semantic paraphasia, to produce disordered phonemic approximations to the target word, to perseverate on a previous response, or to give a neologistic or totally irrelevant response. They rarely assert that they do not know the name and almost never make visual confusions. Children and aphasics operate with a less than full repertoire of grammatical constructions and each sometimes fails to derive the content and syntax of heard utterances. For agrammatic aphasics, the syntax of language is simplified to a string of grammatically and prosodically disconnected short utterances that contain the content words of the message. Their difficulty in producing certain forms seems to differ along several dimensions from the acquisition of grammar in children. The aphasic creates new strategic modes of dealing with his limitations: initiating utterances with stressed vocatives, sequencing content words in a loose pattern, substituting adverbs of degree and time for inflections and functors, and producing predicate adjectives more often than pronominal modifiers.

Phenotypic vs. genotypic sex and cognitive abilities.

Abstract: As a test of whether sex differences in cognitive functioning are determined by chromosomal constitution or hormonal events, eight subjects whose phenotypic sex differed from their genotypic sex were given a standard intelligence test. The results indicated that differences between verbal and nonverbal abilities corresponded to phenotypic rather than genotypic sex. The roles of environmental factors, sex steroid hormones, and alternate genetic mechanisms in determining intellectual dimorphisms are examined.

Reduction of nitrous oxide contamination in a paediatric hospital.

Abstract: Ambient nitrous oxide concentrations were recorded in an operating room during delivery of the gas at low and medium flow-rates, with and without the application of simple scavenging devices. Residual background levels of nitrous oxide were still present more than one hour after disconnection of the flowmeters and use of the room. Scavenging reduced concentrations tenfold. Adjacent corridors and the post-anaesthetic recovery room were contaminated with nitrous oxide from the operating rooms and from patients. A vigorous programme of checking for leaks and repairing and maintaining equipment, coupled with the use of suction scavenging, can reduce atmospheric contamination with nitrous oxide below 30 p.p.m., which is well within the limit suggested by the U.S. National Institute for Occupational Safety and Health.