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Biomedical subjects

R K Wagner

Publications and source records attributed to R K Wagner.

At least 19 recordsLinked to original sources
PubMed1991

The specificity of the effects of stimulant medication on classroom learning-related measures of cognitive processing for attention deficit disorder children.

There appear to be beneficial effects of stimulant medication on daily classroom measures of cognitive functioning for Attention Deficit Disorder (ADD) children, but the specificity and origin of such effects is unclear. Consistent with previous results, 0.3 mg/kg methylphenidate improved ADD children's performance on a classroom reading comprehension measure. Using the Posner letting-matching task and four additional measures of phonological processing, we attempted to isolate the effects of methylphenidate to parameter estimates of (a) selective attention, (b) the basic cognitive process of retrieving name codes from permanent memory, and (c) a constant term that represented nonspecific aspects of information processing. Responses to the letter-matching stimuli were faster and more accurate with medication compared to placebo. The improvement in performance was isolated to the parameter estimate that reflected nonspecific aspects of information processing. A lack of medication effect on the other measures of phonological processing supported the Posner task findings in indicating that methylphenidate appears to exert beneficial effects on academic processing through general rather than specific aspects of information processing.

Arousal↗
PubMed1990

Regional rates of myocardial fatty acid metabolism: comparison with coronary angiography and ventriculography.

In 50 patients, 1 mCi 123I phenylpentadecanoic acid (IPPA) was injected at peak ergometric stress and 1500 frames were acquired (1 frame/s) with a high count rate gamma camera. Parametric images of rates of decrease and increase for different time intervals after stress were compared with coronary angiography and LV ventriculography, separately evaluating the 3 main coronary territories: 18/150 territories supplied by normal coronaries presented rather homogeneous regional clearing rates, whereas a gradual decrease in clearing rates towards the end of the territory (frequently with peripheral defects) was seen in all 87/150 territories with significant coronary narrowing. In local correspondence to clearing defects, initial IPPA accumulations could be observed with later onset of clearing between 10 and 25 min. 44/150 territories presented abnormal clearing rates, mostly with a patchy pattern, with normal coronary anatomy, but all except one had LV dysfunction and a clinical diagnosis of cardiomyopathy, diabetes mellitus or hypertensive disease. Twenty four of the 41 patients with CAD had, in correspondence to a prior myocardial infarction, minimum or missing metabolic activity frequently in circumscribed zones, partly separated by bridges of still viable tissue with preserved but reduced clearing rates.

Angiography↗
PubMed1990

[The monitoring of gynecological radiotherapy using serial tumor marker determinations].

In 149 collum and 45 corpus carcinomas tumor marker concentrations in serum have been measured before, during and sex to eight weeks after termination of radiotherapy. For the collum carcinomas (average of FIGO I to IV) the sensitivity of CEA was found to be 51%, SCC 67%, CEA +SCC 80%. In corpus carcinomas CEA had low sensitivity and could not readily be used for therapy monitoring. However, in a number of cases CA125 was a good substitute. Six to eight weeks after termination of radiotherapy the average tumor marker levels have been declined by comparison with the pretherapeutic values (100%): For the collum carcinoma CEA dropped to 39%, SCC to 57%; for the corpus carcinoma CEA to 72%, CA 125 to 81%. The highest diagnostic information was gained by comparison of post-therapeutical tumor-marker levels with cut off values obtained from healthy women of the same age group. After treatment in 29 of 106 collum carcinomas CEA and or SCC levels did still exceed these cut off values. In eleven cases this marker elevation was due to paraaortic lymph node metastases, in seven cases a local tumor residue was discovered and in six cases general metastases. In corpus carcinomas the main reason for post-therapeutic elevated CA125 values also were paraaortic lymph node metastases. Thus, the use of serial tumor marker determination for control of gynecological radiotherapy is a helpful tool in early detecting local tumor residues and metastases. The decision making for further radiotherapeutical measures will be much easier, if accompanying tumor marker determinations have been done during primary radiotherapy.

Antigens, Neoplasm↗
PubMed1989

Developmental and individual differences in performance on phonological synthesis tasks.

This study was conducted in order to examine the role of individual differences in working memory and lexical access in accounting for age and reading skill related differences in performance on phonological synthesis tasks. The performance of 28 kindergarten, first-, and second-grade children with normal reading skills, as well as that of 28 reading-disabled second graders, was compared under four testing conditions. The testing conditions were formed by completely crossing rate of presentation of phoneme strings with type of stimulus to be blended (real or nonword). Both independent variables affected performance on the blending tasks, with better performance obtained at faster presentation rates and with real words. There was a developmental discontinuity in overall performance, with the kindergarten children obtaining substantially lower scores than the first or second graders. In the comparison of second-grade good and poor readers, there was a significant interaction between groups, presentation rates, and type of stimulus. The findings are discussed in terms of their implications for a general model of performance on the sound blending task, as well as their value for interpreting individual differences on the task.

Awareness↗
PubMed1978

The occurrence of steroid-free, "activated" estrogen receptor in target cell nuclei.

New techniques for the adrenalectomy of pigs and for the isolation of pig uterus nuclei are described. The isolated nuclei were analysed for their content of estradiol and of estradiol receptor. The concentration of the latter exceeded that of the hormone in extracts of uterine nuclei from ovariectomized pigs by ratios of 1.8--10.3. Substantial amounts of both monomer and "activated" dimer receptor but no estradiol at all were extracted from uterine nuclei of ovariectomized/adrenalectomized pigs. The mechanism of action of steroid hormones is discussed on the basis of these results.

Adrenal Cortex↗
PubMed1976

Ovarian-independent fluctuations of estradiol receptor levels in mammalian tissues.

Three types of periodic fluctuation in tissue concentrations of estradiol receptor protein have been observed. A seasonal variation is described in the uteri of 12-16-week-old calves and of ovariectomized pigs, and in mammary tumor tissue obtained from postmenopausal women. A circadian rhythm has been demonstrated in uteri of ovariectomized rats. An irregular periodic fluctuation has been found in uteri of ovariectomized and of ovariectomized/hypophysectomized rats, with the period varying from 9 to 15 days. These observations establish that a substantial turnover of receptor occurs in the absence of hormone and that 'normal' baseline values of receptor concentration do not exist.

Animals↗
PubMed1976

Oestradiol- and dihydrotestosterone receptors in normal and neoplastic human mammary tissue.

Human mammary gland and tumours derived from it contain individual receptors for oestradiol) and for dihydrotestosterone. Analysis of 97 mammary cancers by agargel electrophoresis revealed a widely varying pattern of simultaneous occurrence in different concentration ratios (46), sole presence of oestradiol receptor (23) or dihydrotestosterone receptor (8) and absence of both receptors (18). The relevance of the results is discussed and the need for an extensive cooperative study is emphasized.

Adult↗