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Biomedical subjects

R Daniels

Publications and source records attributed to R Daniels.

At least 55 records · Page 3Linked to original sources
PubMed1994

Spinal muscular atrophy in trizygotic triplets.

The clinical, electrophysiological, pathological and genetic findings in trizygotic triplets with spinal muscular atrophy (SMA) are reported. The first child was clinically affected shortly after birth and the third one first showed symptoms at 1 month of age. Electromyography and a muscle biopsy provided evidence of lower motor neuron disease. The second child remains clinically normal, but electromyography showed fibrillation potentials and regular spontaneous motor unit activity at rest. Genetic linkage analysis revealed that the two siblings with typical type 1 SMA had the same chromosome 5q haplotype, and that the second child had a different haplotype. It is considered that in this family there is a link to SMA 5q and there is little possibility that the second child is affected. These data emphasize the need to adhere to strict clinical criteria for the diagnosis of chromosome 5q SMA.

Chromosomes, Human, Pair 5↗
PubMed1994

Monsanto's computer animal proposal system (CAPS).

Regulations and standards must include the minimum requirements with respect to veterinary care, sanitation, handling, feeding, and housing. Part 1 of the Animal Welfare Act regulations was amended to update, clarify, and expand the list of definitions of terms and standards. Section 9 CFR, Part 1, contains definitions and deals with animal welfare, animal housing, dealers, exhibitors, research facilities, and humane animal handling. The subjects in 9 CFR, Part 2, pertain to licensing, registration, identification of animals, records, institutional animal care and use committees, and adequate veterinary care. Animal welfare, humane animal handling, pets, transportation, and reporting and recordkeeping requirements are the subjects listed in 9 CFR, Part 3.

Animal Welfare↗
PubMed1993

Gifted girls in a rural community: math attitudes and career options.

This study was designed to determine the feasibility of improving gifted girls' attitudes toward mathematics. This study was conducted in three school districts in an isolated rural setting. Subjects were 24 gifted girls in Grades 4-7. A control group also contained 24 gifted girls at the same grade levels. On pretest, using the Mathematics Attitude Inventory (MAI), no significant differences were found between groups in their attitudes toward math. The intervention program included problem-solving activities, math-related career options, and self-esteem issues. MAI posttest scores after the 18-week program indicated that the program was effective in changing attitudes toward mathematics of gifted girls in a rural environment.

Anxiety↗
PubMed1992

The influence of posture on the pharmacokinetics of orally administered nifedipine.

1. Nifedipine (20 mg as capsules) and soluble paracetamol (1 g) were co-administered to eight healthy young volunteers on three separate occasions, following which in random order they stood, lay on their left side or lay on their right side for 4 h. 2. The time to maximum plasma concentration of paracetamol was significantly lower when standing or lying on the right side compared with recumbent left, indicating more rapid gastric emptying. 3. The times to maximum plasma concentrations of nifedipine and its metabolite produced at first pass were reduced when standing or lying on the right side. These postures were associated with significantly higher peak plasma concentrations and AUC values of nifedipine but not of its nitropyridine metabolite. 4. The increase in heart rate following nifedipine administration was significantly greater when lying on the right side compared with the left. 5. The data are consistent with transient saturation of first pass metabolism of nifedipine with postures which favour rapid gastric emptying. The results demonstrate the importance of defining the precise posture in studies in which pharmacokinetic and pharmacodynamic measurements are made on drugs which are absorbed rapidly and are subject to presystemic elimination.

Acetaminophen↗
PubMed1990

Genetic mapping of chronic childhood-onset spinal muscular atrophy to chromosome 5q11.2-13.3.

SPINAL muscular atrophy (SMA) describes a group of heritable degenerative diseases that selectively affect the alpha-motor neuron. Childhood-onset SMAs rank second in frequency to cystic fibrosis among autosomal recessive disorders, and are the leading cause of heritable infant mortality. Predictions that genetic heterogeneity underlies the differences between types of SMA, together with the aggressive nature of the most-severe infantile form, make linkage analysis of SMA potentially complex. We have now analysed 13 clinically heterogeneous SMA families. We find that 'chronic' childhood-onset SMA (including intermediate SMA or SMA type II, and Kugelberg-Welander or SMA type III) is genetically homogeneous, mapping to chromosomal region 5q11.2-13.3.

Adolescent↗
PubMed1989

Role of costal and crural diaphragm and parasternal intercostals during coughing in cats.

The inspiratory phase of coughs often consists of large inspired volumes and increased motor discharge to the costal diaphragm. Furthermore, diaphragm electrical activity may persist into the early expiratory portion of coughs. To examine the role of other inspiratory muscles during coughing, electromyograms (EMG) recorded from the crural diaphragm (Dcr) and parasternal intercostal (PSIC) muscles were compared to EMG of the costal diaphragm (Dco) in anesthetized cats. Tracheal or laryngeal stimulation typically produced a series of coughs, with variable increases in peak inspiratory EMGs of all three muscles. On average, peak inspiratory EMG of Dco increased to 346 +/- 60% of control (P less than 0.001), Dcr to 514 +/- 82% of control (P less than 0.0002), and PSIC to 574 +/- 61% of control (P less than 0.0005). Augmentations of Dcr and PSIC EMG were both significantly greater than of Dco EMG (P less than 0.05 and P less than 0.002, respectively). In most animals, EMG of Dco correlated significantly with EMG of Dcr and of PSIC during different size coughs. Electrical activity of all three muscles persisted into the expiratory portions of many (but not all) coughs. The duration of expiratory activity lasted on average 0.17 +/- 0.03 s for Dco, 0.25 +/- 0.06 s for Dcr, and 0.31 +/- 0.09 s for PSIC. These results suggest that multiple respiratory muscles are recruited during inspiration of coughs, and that the persistence of electrical activity into expiration of coughs is not unique to the costal diaphragm.

Animals↗
PubMed1988

Cell growth and division in relation to differentiation of mouse erythroleukemia cells.

Addition of certain inhibitors of RNA or protein synthesis to cells cultured in 20% serum, but not 5% serum, induces the differentiation of mouse erythroleukemia cells. Differentiation also was induced by culture at a low serum concentration (0.1%) to starve cells to quiescence, then inducing division by exposing cells to either of two high-pH regimes.

Alanine↗
PubMed1985

The sympathetic nervous system in human obesity.

No evidence for increased thermic sensitivity to NE during mixed nutrient overfeeding in humans was found by the authors although in small rodents increased NE sensitivity is an important regulator of adaptive thermogenesis. Additionally no intrinsic defect in the thermic response of NE in two separate groups of obese individuals was found by the authors but an apparent decrease in the plasma appearance rate of NE in one group of homogeneously obese subjects was noted, the clinical significance of which remains to be determined.

Basal Metabolism↗
PubMed1981

Syntheses and biological evaluation of 2- and 9-aminobenzonorbornenes as conformationally rigid analogs of amphetamines.

Isomers of the 2- and 9-aminobenzonorbornenes were prepared as rigid analogs of amphetamine and were employed to study the conformational requirements of indirectly acting sympathomimetic agents. Of this series of isomeric amines, the exo-2 and anti-9 isomers closely resemble the fully extended conformation of amphetamine. The other two amines, the endo-2 and syn-9 isomers, conformationally resemble the folded conformation of amphetamine. The isomers that resemble the extended conformation of amphetamine increased the spontaneous motor activity in mice while the isomers resembling the folded form either decreased or had no effect on motor activity. These compounds also were studied for their ability to accelerate the efflux of tritiated norepinephrine from vesicular and nonvesicular storage sites of isolated perfused rabbit atria; either alpha-methyl-p-tyrosine- or reserpine-pretreated rabbits were used. Amphetamine and the exo-2 and anti-9 isomers of aminobenzonorbornene could accelerate norepinephrine efflux from either compartment while the endo-2 and syn-9 isomers could accelerate the efflux from only the nonvesicular compartment at the concentrations studied. Fenfluramine and methylphenidate also were studied for their ability to accelerate efflux. Fenfluramine and methylphenidate resembled the aminobenzonorbornenes that correspond to the folded conformation of amphetamine in their ability to accelerate the efflux from nonvesicular storage. However, fenfluramine also resembled amphetamine and the aminobenzonorbornenes corresponding to the extended conformation of amphetamine in its ability to accelerate efflux from vesicular storage sites. The response to methylphenidate was similar to that of the aminobenzonorbornenes resembling the folded conformation of amphetamine.

Amphetamines↗
PubMed1979

1,2-Dialkyl-4-pyrazolidinethiols as potential antiradiation agents.

The reaction between 3-chloropropylene sulfide and the 1,2-dialkylhydrazines was employed to prepare a series of 1,2-dialkyl-4-pyrazolidinethiols. Evidence is presented to support the structure proposed for the product. These mercaptoheterocycles are related to the beta-mercaptoethylamines and were prepared as potential radiation protective agents. No significant activity was observed.

Animals↗