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Biomedical subjects

K N Shaw

Publications and source records attributed to K N Shaw.

At least 55 records · Page 3Linked to original sources
PubMed1988

Serum theophylline testing in a pediatric emergency setting: potential benefit of rapid assays.

This study assessed the potential clinical benefit of rapid theophylline assays in an urban pediatric emergency department by 1) examining current practices of monitoring and adjusting theophylline therapy in children with asthma and 2) determining the relationship between these practices and the adequacy of theophylline therapy and duration of emergency department visits. Of 213 consecutive wheezing children who reported taking theophylline, levels were not obtained on 114 (52%), even though theophylline dosages were adjusted for 43 (38%). Of the 99 patients who had theophylline levels drawn, 80 were successfully enrolled in the study. Most children who received intravenous theophylline therapy 1) were treated prior to availability of serum theophylline results (83%), which took an average of one hour and 48 minutes, and 2) received suboptimal doses (12% were excessive, and 57% were inadequate). The latter patients were more likely to require additional intravenous theophylline that prolonged their stay in the emergency department. If intravenous theophylline therapy was not administered, the wait for the theophylline level was longer than the visit itself. These findings indicate that rapid immunoassays for theophylline have the potential to improve management of children with acute asthma in an emergency department by improving the accuracy of dosing and decreasing the duration of stay.

Asthma↗
PubMed1988

Correlates of reported smoke detector usage in an inner-city population: participants in a smoke detector give-away program.

As part of a smoke detector give-away program, 388 adults were surveyed to characterize smoke detector ownership in a low-income population and to identify those who would acquire a free smoke detector following their child's visit to the hospital. Factors associated with smoke detector ownership included higher education, home ownership (vs public housing), knowledge of the city smoke detector law, and the practice of other injury prevention measures. Regardless of ownership, the great majority of parents (82 per cent) acquired a free smoke detector, but those previously without a smoke detector were more likely to do so. These characteristics of smoke detector usage and acquisition should be considered in targeting future intervention strategies.

Adolescent↗
PubMed1986

Methylmalonic and propionic acidemias: lipid profiles of normal and affected human skin fibroblasts incubated with [1-14C]propionate.

Normal human skin fibroblasts and those from methylmalonic acidemia and propionic acidemia patients were grown in culture. Following incubation with [1-14C]propionate, the major lipid classes in the cells were separated by thin layer chromatography and isolated fractions analyzed by radio gas chromatography for the presence of odd-numbered long-chain fatty acids; the pattern of even-numbered long-chain fatty acids was obtained also. Normal fibroblasts incorporated a small percentage of propionate into odd-numbered fatty acids which were present in all lipids studied. The abnormal cells incorporated a larger amount while maintaining the characteristic ratios of odd-numbered fatty acids found in the normal line. Most of the radioactivity was associated with phospholipids which are the predominant constituents of cell membranes. A characteristic C15/C17 ratio was found for different phospholipids and the triglyceride fraction; pentadecanoic acid was the principal odd-numbered fatty acid utilized in the assembly of complex lipids. Compared to even-numbered long-chain fatty acids the absolute amount of odd-numbered fatty acids was low (1-2%), even in affected cells. An unusual polar lipid fraction was isolated in the course of the study. In the normal cell it contained several unlabeled eicosanoids which were missing from the same fraction of both affected cell lines.

Amino Acid Metabolism, Inborn Errors↗
PubMed1984

Immune functions in methylmalonicaciduria.

A variety of phagocytic cell and lymphocyte assays were employed to evaluate the immune status of four patients with methylmalonicaciduria . One patient had a depressed absolute granulocyte count and two patients had depressed neutrophil and monocyte chemotactic responses. All subjects had normal neutrophil phagocytic and bactericidal activities. One patient had a decreased T-cell number; blastogenic responses to phytohaemagglutinin and pokeweed mitogen were normal in all subjects. B lymphocyte measurements were variably abnormal; two children had decreased B-cell numbers; two had marginally decreased IgG levels; a third had an undetectable rubella titre; and two had elevated serum IgE concentrations. In vitro exposure of normal cells to methylmalonic acid concentrations up to 50 mg/100 ml did not affect chemotactic or lymphoproliferative responses. In conclusion, although B-cell function may be affected, no consistent abnormality of lymphocyte or phagocytic cell functions could be attributed to the metabolic disorder.

Acidosis↗
PubMed1984

Partial ornithine transcarbamylase deficiency associated with recurrent hyperammonemia, lethargy and depressed sensorium.

A 6-year-old boy presented with recurrent coma associated with hyperammonemia and infection is reported. A liver biopsy revealed decreased ornithine transcarbamylase (OTC) activity (16% of normal). The enzymatic abnormality in the child is supported by the finding of elevated orotic acid excretion in his mother following a protein load, compatible with an X-linked pattern of inheritance. Since initiation of a dietary arginine supplement, the child has not had recurrent episodes of hyperammonemia.

Amino Acid Metabolism, Inborn Errors↗
PubMed1983

Neonatal pyruvate carboxylase deficiency with renal tubular acidosis and cystinuria.

This report concerns a patient with severe congenital lacticacidosis associated with proximal renal tubular acidosis and cystinuria. Enzyme studies with cultured skin fibroblasts obtained from the patient revealed zero pyruvate carboxylase activity, but propionyl-CoA carboxylase activity was normal. Administration of various vitamins in large amounts did not improve the clinical condition. In contrast, the patient began to thrive when her diet was supplemented with aspartic acid, asparagine, glutamic acid, and glutamine. The particular dietary treatment used and the biochemical findings merit consideration for management of future cases.

Acidosis↗
PubMed1982

Treatment of hyperargininaemia due to arginase deficiency with a chemically defined diet.

A brother and sister aged 11 and 17 years have been reported previously to have hyperargininaemia and arginase deficiency: they were treated with a semi-synthetic diet consisting of fat, carbohydrate, minerals, vitamins and essential amino acids in amounts equivalent to 0.55-0.65 g protein kg-1 day-1 for 2 years. Plasma arginine levels fell from 0.50-0.90 mumol/1 to 0.13-0.30 mumol/1 (normal range 0.02-0.15). Increased concentrations of arginine in the cerebrospinal fluid (CSF) fell from 0.069-0.098 mumol/l to 0.040-0.056 mumol/l (normal mean +/- SD = 0.020 +/- 0.006). Dibasic aminoaciduria returned to normal within 1 week. Substitution of the keto-acid analogues of five essential amino acids in the formula lowered arginine concentrations further, but proved to be unpalatable. Urinary concentrations of orotic acid, uridine and uracil fell toward normal but remained increased, even when the plasma ammonia concentration was measured as normal. Both patients showed a stable clinical improvement.

Adolescent↗
PubMed1979

Hyperlysinemia with saccharopinuria due to combined lysine-ketoglutarate reductase and saccharopine dehydrogenase deficiencies presenting as cystinuria.

A 7-year-old boy with speech delay, hyperactive behavior, and minor neurologic abnormalities had been found in the past to have "intermittent cystinuria." A more detailed investigation revealed hyperlysinemia and hyperlysinuria, with lesser increases in urinary excretion of arginine and cystine. The plasma and urine abnormalities increased on a diet of 3 gm of protein/kg body weight/day. Saccharopine, a normal metabolite of lysine not found in the body fluids of normal people, was present in plasma, cerebrospinal fluid, and urine of the patient. Lysine-ketoglutarate reductase and saccharopine dehydrogenase activities were not detectable in extracts of cultured skin fibroblasts. Re-examination of the urine of previously studied cases of this double enzyme deficiency suggests that saccharopinuria of variable degree is the rule and not the exception.

Cells, Cultured↗
PubMed1978

Ultrastructural studies on neuroblastoma: evaluation of cytodifferentiation and correlation of morphology and biochemical and survival data.

Fifteen cases of neuroblastoma, ganglioneuroblastoma and ganglioneuroma were studied by electron microscopy. Ultrastructural features of cytodifferentiation, including numbers of dense core neurosecretory granules (NSG) and neuritic processes, were used to evaluate variation within the neuroblastoma group to determine whether differences in cytodifferentiation exist where light microscopic variations are not evident. These studies revealed that undifferentiated neuroblastomas do show ultrastructural variations not evident by light microscopy. The ultrastructural findings for each case were compared with initial urinary catecholamine excretory patterns, the latter having recently been shown to have valuable prognostic significance. There was a positive correlation, in the undifferentiated neuroblastomas, between increased numbers of NSG and prognostically favorable biochemical excretory patterns. Conversely, low numbers of NSG were associated with an unfavorable biochemical pattern and fatal clinical course. These correlations between ultrastructural differentiation and the biochemical secretory pattern indicate that ultrastructural evaluation of undifferentiated neuroblastomas would appear to have prognostic value, particularly in cases lacking initial biochemical data or as an adjunct to biochemical studies.

Abdominal Neoplasms↗
PubMed1978

Initial urinary catecholamine metabolite concentrations and prognosis in neuroblastoma.

Initial urinary catecholamine metabolite and amino acid excretion patterns were examined in 54 children with neuroblastoma. The relationships between prognosis and age at diagnosis, stage of disease, primary site, and histologic grade of tumor were similar in this population to those found in previous studies, but only age and stage were found to be independent prognostic variables. Prognosis in disseminated disease was found to correlate directly with the urinary vanilmandelic acid (VMA)/homovanillic acid (HVA) ratio but not with the absolute levels of HVA. The presence of the dopa metabolite, vanillactic acid, as well as increased amounts of cystathionine and/or low levels of VMA indicated poor prognosis. These results are consistent with the hypothesis that biochemically primitive neuroblastomas deficient in dopamine beta-hydroxylase are move virulent than their mature analogues which produce epinephrine, norepinephrine, and their metabolites.

Adrenal Gland Neoplasms↗