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Biomedical subjects

C Nelson

Publications and source records attributed to C Nelson.

At least 163 records · Page 9Linked to original sources
PubMed1987

Field replication of classwide peer tutoring.

We conducted a large-scale field replication study of classwide peer tutoring applied to spelling instruction (Greenwood, Delquadri, & Hall, 1984). Two hundred and eleven inner-city students in four schools participated during their first- and second-grade school years. The effects of classwide peer tutoring were compared to teacher instructional procedures and pretest probes using a group replication design (Barlow, Hayes, & Nelson, 1984). Analysis of group and individual results indicated that (a) both teacher instructional procedures and classwide peer tutoring were effective in increasing spelling performance above pretest levels, (b) peer tutoring produced statistically greater gains relative to the teachers' procedures for both low and high student groups formed on pretest levels, (c) these outcomes were representative of groups, classes, individuals, and years during the project, and (d) participant satisfaction with the program was generally high. A separate analysis of the social importance of treatment outcome revealed differential findings for low and high groups related to pretest levels. Implications of these findings are discussed.

Achievement↗
PubMed1986

Inadvertent middle cerebral artery embolism by a detachable balloon: management by embolectomy. Case report.

A case of middle cerebral artery embolism by a detachable intra-arterial balloon is presented. The balloon migrated after being detached in an effort to occlude the internal carotid artery proximal to an unclippable giant paraclinoid aneurysm. Volume expansion, induced hypertension, anticoagulation therapy, rapid middle cerebral artery embolectomy, and good collateral circulation are factors that may have contributed to the patient's complete recovery from hemiplegia.

Collateral Circulation↗
PubMed1986

Dry-reagent strips for measuring phenytoin in serum.

A new reagent strip has been developed for measuring phenytoin in serum or plasma. It utilizes the chemistry of the Apoenzyme Reactivation Immunoassay System (ARIS) and is designed for use with the Seralyzer reflectance photometer. The 90-s test relies on comparison of strip reactivities with a two-point calibration line, which can be validly stored in the instrument for two weeks. Within-run CVs for controls at five concentrations ranged from 2.7 to 5.6%, between-run CVs from 2.3 to 6.3%. Phenytoin values obtained for clinical serum samples correlated well (r greater than 0.99) with those obtained by liquid chromatography or substrate-labeled fluorescent immunoassay. The speed and convenience of this assay for monitoring phenytoin in serum make it well suited for decentralized test sites such as emergency rooms, urgent-care centers, and physician's offices.

Chromatography, High Pressure Liquid↗
PubMed1984

Effects of elevated prolactin and its normalization on thyroid hormone, cardiac beta-adrenoreceptor number and beta-adrenergic responsiveness.

Subcutaneous inoculation of the prolactin secreting MtTW15 adenoma in male Wistar Furth rats for 4 weeks produced a significant increase in serum prolactin and a corresponding decrease in peripheral beta-adrenergic responsiveness. Both the isoproterenol induced drink and heart rate responses used to assess the beta-adrenergic responsiveness were significantly reduced in the hyperprolactinemic rat. Serum T3 and T4 levels were measured as was cardiac beta-adrenergic receptor number to ascertain if an alteration of thyroid hormone and a resultant decrease in beta-adrenergic receptor number was responsible for the attenuated beta-adrenergic responsiveness. Serum T4 was significantly reduced in the hyperprolactinemic group (1.9 +/- 0.3 microgram%) as compared to the control group (6.4 +/- 0.l5 microgram%). However there was no significant difference in serum T3 or in cardiac beta-adrenergic receptor number between the two groups. Removal of the MtTW15 adenoma resulted in a normalization of serum prolactin, T4, and in the responsiveness of the peripheral beta-adrenergic system within 4-6 weeks. These results indicate that the attenuated beta-adrenergic responsiveness associated with hyperprolactinemia is reversible and not dependent on a reduction in beta-adrenergic receptor number.

Adenoma↗
PubMed1984

Hypophyseal metastatic renal cell carcinoma and pituitary adenoma. Case report and review of the literature.

A patient with a remote history of nephrectomy for renal cell carcinoma presented with a visual field defect. At surgery, a metastasis from the hypernephroma and an adenoma were found coexisting in the anterior pituitary gland. Although hypernephromas are known to act as "recipient" tumors in cases in which two primary neoplasms coexist, it is unusual for a renal cell carcinoma to metastasize into another tumor.

Adenocarcinoma↗
PubMed1984

Chemical modification of gamma-carboxyglutamic acid, the vitamin K-dependent amino acid which binds Ca2+.

gamma-Carboxyglutamic acid (Gla), the vitamin K-dependent Ca2+ binding amino acid, can be chemically modified in several specific reactions. Practical outlines of the published procedures for the thermal decarboxylation of Gla to Glu in dry proteins and the specific exchange labeling of the gamma-proton of Gla with tritium are presented. The applications of these procedures in the analysis of the role of Gla residues in Ca2+ binding and in biological activity are also discussed. In addition, the reversible formation of pyro-gamma-carboxyglutamic acid is described for the first time. Pyro-gamma-carboxyglutamic acid is formed from Gla in over 99% yield in a first-order reaction with a half-time of 3.5 h at pH 10 and 110 degrees C. The mass spectrum of the dimethyl ester of the reaction adduct is consistent with pyro-gamma-carboxyglutamic acid and treatment of the reaction adduct with 2 M KOH for 24 h at 110 degrees C quantitatively regenerates Gla. The applications of this reversible reaction to the quantitative analysis of Gla in proteins are discussed.

1-Carboxyglutamic Acid↗
PubMed1984

Median nerve F-wave conduction in healthy subjects.

This study of the normal median nerve was designed to compare techniques of using the shortest and average F-wave latencies, F-wave values between extremities, and F-wave values with the conventional motor response values and to determine the relationships between F-wave latency and arm length. We examined 40 median nerves in 20 subjects with no known pathology. The motor response latency was measured from wrist and elbow stimulation sites by conventional techniques. We then applied multiple stimuli at the same sites to record a series of 10 F-wave latencies and determined shortest and average F-wave latencies. Values of F-wave and M-response conduction are reported. No significant difference was found in F-wave latency or velocity between extremities within subjects, using either the shortest or average latency technique. We propose a formula for calculating the estimated F-wave distal latency based on the conventional motor response distal latency. The F-wave conduction velocities of the forearm were faster and more variable than the motor nerve conduction velocities. A high correlation was found between F-wave distal latency and arm length. Using the method described, the F wave can be a useful measure in evaluating the conduction of proximal segments of peripheral motor nerves.

Adolescent↗
PubMed1983

Impact of choice of anesthetic with vagotomy testing.

Incomplete vagotomy is the most important cause of recurrent ulcer disease. Despite this, intraoperative vagotomy testing has not gained widespread acceptance. We used a technique with Congo red, a nontoxic azine dye that turns black (pH, 3.0) intraoperatively. The vagolytic effects of various general anesthetics has been shown. We found that halothane, used as a general anesthetic, combined with pentagastrin administration as a vagally synergistic stimulant, produced the most reliable, safe, and reproducible result when using Congo red intraoperatively.

Anesthesia, General↗