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N Hill

Publications and source records attributed to N Hill.

62 records · Page 4Linked to original sources
PubMed1975

Atopic hypersensitivity to cis-dichlorodiammineplatinum(II) and other platinum complexes.

Allergic reaction to an antitumor agent, cis-dichlorodiammineplatinum(II) (DDP) was investigated. A 15-year-old white male with pulmonary metastases from embryonal carcinoma of testis was treated with a combination of DDP, bleomycin, and vinblastine. The dose of DDP varied from 2 to 2.25 mg/kg given i.v. He received 7 doses of DDP in 9 months. An anaphylactic reaction was seen within 3 min of the initiation of i.v. infusion of the 8th dose of DDP. The reaction was due to atopic hypersensitivity, as confirmed by an immediate wheal and flair reaction and increased histamine release from leukocytes with DDP. His serum IgE level was elevated. Neither the presence of chloride nor the amine grouping in DDP was essential for reactivity. The replacement of platinum with palladium abrogated the reactivity. There was no cross-reactivity with 3 other platinum complexes of known antitumor activity (platinum blue, platinum(II) 1,2-diaminocyclohexane malonate, and platinum(II) ethylenediamine malonate). This was also confirmed by the lack of reaction to subsequent i.v. administration of platinum(II) 1,2-diaminocyclohexane malonate (10 mg/kg) in this patient.

Adolescent↗
PubMedDate not supplied

Classification of 1H MR spectra of human brain neoplasms: the influence of preprocessing and computerized consensus diagnosis on classification accuracy.

We study how classification accuracy can be improved when both different data preprocessing methods and computerized consensus diagnosis (CCD) are applied to 1H magnetic resonance (MR) spectra of astrocytomas, meningiomas, and epileptic brain tissue. The MR spectra (360 MHz, 37 degrees C) of tissue specimens (biopsies) from subjects with meningiomas (95; 26 cases), astrocytomas (74; 26 cases), and epilepsy (37; 8 cases) were preprocessed by several methods. Each data set was partitioned into training and validation sets. Robust classification was carried out via linear discriminant analysis (LDA), artificial neural nets (NN), and CCD, and the results were compared with histopathological diagnosis of the MR specimens. Normalization of the relevant spectral regions affects classification accuracy significantly. The spectra-based average three-class classification accuracies of LDA and NN increased from 81.7% (unnormalized data sets) to 89.9% (normalized). CCD increased the classification accuracy of the normalized sets to an average of 91.8%. CCD invariably decreases the fraction of unclassifiable spectra. The same trends prevail, with improved results, for case-based classification. Preprocessing the 1H MR spectra is essential for accurate and reliable classification of astrocytomas, meningiomas, and nontumorous epileptic brain tissue. CCD improves classification accuracy, with an attendant decrease in the fraction of unclassifiable spectra or cases.

Astrocytoma↗
PubMedDate not supplied

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Absenteeism↗
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Membrane potential of rat adipocytes: effect of phospholipase C, concanavalin A, and adenosine.

The change in transmembrane potential of rat adipocytes was measured using the fluorescent probe 3,3'-diethylthiadicarbocyanine iodide, diS-C2-(5). The method was calibrated by altering the potassium ion concentration while keeping the sum of potassium and sodium ions at a constant concentration of 153 mM (Bailey et al: Bioelectrochem. Bioenergetics 21:333-42, 1989). Two insulin-mimetic agents, phospholipase C from Clostridium perfringens and concanavalin A, induced a dose dependent hyperpolarization of rat epididymal adipocytes, like insulin. Removal of endogenous adenosine with adenosine deaminase or adenosine receptor blockade with isobutylmethylxanthine following the initiation of insulin-induced hyperpolarization resulted in depolarization. These same agents induced hyperpolarization of -6 to -8 mV when added without insulin. The replacement of adenosine with its analogue, N6-phenylisopropyladenosine, plus insulin depolarized the cells toward the transmembrane potential established by insulin, -2.0 mV. These studies suggest that adenosine receptor occupancy is required to maintain insulin-induced hyperpolarization.

1-Methyl-3-isobutylxanthine↗