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Biomedical subjects

G Rodriguez

Publications and source records attributed to G Rodriguez.

At least 163 records · Page 9Linked to original sources
PubMed1982

Programming time as a function of response duration: a replication of "dit-dah" without possible guessing artifacts.

Reaction time was longer prior to longer-lasting pressing responses for low probability, unanticipated movements. By contrast, reaction time was independent of response duration for high probability, anticipated movements. This replicates and extends previous findings for choice and simple reaction time in the "dit-dah" paradigm. The present results (unanticipated responses) cannot be given a selective anticipation interpretation because the comparison is between responses which are never anticipated. The previous paradigm was open to an alternative interpretation in which selective anticipation of dit rather than dah could have produced the differences in choice reaction time. Confirmation of the finding that variations in required response duration lead to differences in reaction time supports the view that the underlying parameter of "complexity" in the "memory drum theory" may be response duration.

Journal Article↗
PubMed1982

Growth hormone, prolactin and cortisol nyctohemeral variations during naloxone-induced opiate receptor blockade in man.

To evaluate the role of endogenous opioid peptides in prolactin (Prl), growth hormone (GH) and cortisol neuroregulation, 50 mg of the opiate antagonist naloxone was infused over 24 h to 6 normal male volunteers. An additional naloxone dose (5 mg) was given iv as a bolus injection at 20.00 h. blood specimens were collected hourly by means of a portable constant withdrawal pump. Naloxone failed to alter 24 h secretion of GH and Prl. The sleep-related GH and Prl rise was also unaffected by the opiate blocker. Moreover, naloxone failed to alter the circadian rhythm of cortisol and its 24 h concentration. The results do not suggest, a major role of opiate receptors in spontaneous GH, Prl and cortisol secretion in man.

Adult↗
PubMed1980

A computer analysis of specific and aspecific interictal epileptic activity in man.

The preliminary results are reported for a systematic computerized analysis of interictal EEG recordings from patients with different epileptic syndromes. Both interical specific epileptic activity and non-specific background EEG signals are processed by special programs. Specific achievement are: a) Automatic recognition of spikes and quantification in every channel of their temporal incidence; b) definition of morphology and temporal relationship among spikes simultaneously recorded from different cortical and subcortical structures. Non-specific achievement: a) Characterization of background pattern; b) identification, quantification and localization of pathological frequencies. The study of changes in the described parameters induced by pharmacological therapies and measured drug plasma levels, has supplied additional criteria for the evaluation of epileptic dynamics and the monitoring of optimal treatment modes.

Computers↗
PubMed1978

Epidemiology of endemic goitre in western Colombia.

This paper reports on recent epidemiological observations in western Colombia, which further demonstrate the presence of naturally-occurring goitrogens contaminating water supplies in areas where goitre persists despite prolonged and continuous iodine supplementation. 'Prospective' and 'cross-sectional' studies in 41 localities where the populations have been on a uniform and adequate iodine supplementation for the last 10-20 years indicate that, in the endemia of western Colombia, environmental factors other than nutritional iodine deficiency are responsible for differences in goitre prevalence. Further epidemiological studies to determine the causal factors for the persistence of the endemia established a correlation between the sources of drinking water and goitre prevalence rates. Organic compounds containing sulfur with marked thionamide-like antithyroid activity were isolated from water supplying endemic goitre districts, and results are presented supporting the hypothesis that sedimentary rocks rich in organic matter are the main source of water-borne goitrogens. Bacteriological investigations showed that the presence of Klebsiella pneumoniae in drinking water and bacterial concentration were related significantly with goitre prevalence only in the presence of other variables, particularly the presence of sedimentary rocks. In the light of these epidemiological observations and experimental studies it may be concluded that, at present, endemic goitre in western Colombia is not due to nutritional iodine deficiency, but that water supplies are contaminated with sulfur-bearing organic compounds with thionamide-like antithyroid activity most probably deriving from sedimentary rocks rich in organic matter and that these compounds are the main factor underlying the endemia.

Adolescent↗
PubMed1977

Computerized EEG analysis for studying the effect of drugs on the central nervous system.

Samples of our experience in quantitative pharmaco-EEG are reviewed to discuss and define its applicability and limits. Simple processing systems, such as the computation of Hjorth's descriptors, are useful for on-line monitoring of drug-induced EEG modifications which are evident also at the visual visual analysis. Power spectral analysis is suitable to identify and quantify EEG effects not evident at the visual inspection. It demonstrated how the EEG effects of compounds in a long-acting formulation vary according to the sampling time and the explored cerebral area. EEG modifications not detected by power spectral analysis can be defined by comparing statistically (F test) the spectral values of the EEG from a single lead at the different samples (longitudinal comparison), or the spectral values from different leads at any sample (intrahemispheric comparison). The presently available procedures of quantitative pharmaco-EEG are effective when applied to the study of mutltilead EEG recordings in a statistically significant sample of population. They do not seem reliable in the monitoring of directing of neuropyschiatric therapies in single patients, due to individual variability of drug effects.

Alcoholic Intoxication↗
PubMed1976

An approach to the analysis of menstrual patterns in the critical evaluation of contraceptives.

An approach to a standardized analysis of menstrual bleeding patterns is presented. The method utilizes a prospective bleeding record and characterizes the menstrual pattern of a woman according to bleeding and nonbleeding events without imposing definitions of cycle or intermenstrual bleeding. Further, the analysis is done within a time reference period similar to life-table analysis, with the experience of each woman having equal value. The method is thus applicable to the study of menstrual patterns of both normal, untreated women, and women on experimental contraceptive regimens in which expected bleeding patterns are disrupted. The methodology is aided by computer programs to process the data and by the use of standard statistical packages for comparison of output data of different groups.

Computers↗