Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “generalization”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1978

Changes of sensitivity to the cuing properties of narcotic drugs as evidenced by generalization and cross-generalization experiments.

With a discrete-trial, food-reward, two-lever procedure, rats were trained to discriminate 0.04 mg/kg fentanyl from saline. Individual threshold doses for generalization of fentanyl and for cross-generalization of morphine were determined repeatedly during a 17-week posttraining period. Threshold doses of both drugs almost continuously shifted in both the up- and downward direction. Shifts of fentanyl threshold doses covaried with those of morphine threshold doses. These shifts can best be described by a sustained oscillation, the mean amplitude of which amounts to a factor 3.65 of the dose-range for fentanyl, and to a factor 1.85 for morphine. The upper and lower limits of oscillation were symmetrical with respect to baseline. The oscillation can be described by a function expressing that the more distant a point along the function is from the baseline, the more it is susceptible to (positive/negative) acceleration along the intensity (i.e., dose) axis.

Animals↗
PubMed1979

General practitioners and postgraduate education in the Northern Region.

We describe a survey of general practitioners in the Northern Region which was carried out during the summer of 1977 as the result of a commission from the Education Committee of the North of England Faculty of the Royal College of General Practitioners. Seventy-five per cent of a one in two random sample of general practitioner principals returned a postal questionnaire in which their perceptions of postgraduate education were sought and their behaviour measured by the number of sessions they attended during the previous year at their 'usual' and other postgraduate centres. Almost half the respondents had more than a basic qualification and all but three per cent had held full-time hospital appointments, two thirds of them at the level of senior house officer or above. Their experience as general practitioner principals averaged 15 years and 57 per cent held part-time appointments outside their practices. Only four per cent had not attended any postgraduate events during the previous year but the remaining respondents had attended eight sessions on average, six of which were at their usual centres. Those attending more than the average number of sessions tended to have registered between 1950 and 1969, to work in larger practices, to hold additional appointments, or to be trainers or College tutors. Most of the respondents were conservative in their perceptions of teaching methods, the topics discussed at meetings, and the contributors to postgraduate education but the younger general practitioners and a group of established general practitioners affiliated to the Royal College of General Practitioners held more radical views. They agreed about the primacy of traditional clinical topics but were sceptical of the value of ward rounds and formal lectures and favoured the seminar and clinical attachments. They saw a need for more material about practice management and wanted experienced general practitioners and community paramedical staff as teachers in addition to hospital consultants. Most of the respondents believed that their usual centres were well organized and managed but failed to cater for the special requirements of general practitioners in non-clinical aspects of practice. Lunchtime and evenings were seen as the most convenient for weekday meetings and Sunday as the most convenient day of the week. A majority of respondents believed that post-graduate education had altered their practice of clinical medicine but only 15 per cent believed it had caused changes in their practice organization.

Education, Medical, Continuing↗
PubMed1977

Pathophysiology of generalized penicillin epilepsy in the cat: the role of cortical and subcortical structures. I. Systemic application of penicillin.

The mechanism of precipitation of generalized epileptiform discharges in feline generalized penicillin epilepsy, a model of human generalized corticoreticular ('centrencephalic') epilepsy, was studied in acute and chronic experiments in cats with implanted skull and intracerebral electrodes. Single shock and low frequency repetitive stimulation of subcortical sites from which prior to penicillin administration spindle activity and recruiting responses could be elicited, readily triggered epileptiform discharges in the same animals after penicillin. These structures comprised the intralaminar and midline thalamic nuclei, the neostriatum, and some posterior thalamic association nuclei (Pulvinar and nucleus lateralis posterior). Subcortical and cortical structures which prior to penicillin elicited neither spindle activity nor recruiting responses were significantly less effective in triggering generalized epileptic bursts after penicillin injection. The probability with which such bursts were elicited from these structures was still, however, in many instances above chance level. It is concluded that the generalized epileptiform discharges in feline generalized penicillin epilepsy can be triggered from a large number of brain sites, but most reliably so from subcortical nuclei involved in spindle generation and recruiting responses. The experimental evidence presented still does not allow one to determine whether epileptic alteration of neuronal function in this form of epilepsy primarily resides in cortical or subcortical nerve cells or in both.

Animals↗
PubMed1979

Effects of changes in cortical excitability upon the epileptic bursts in generalized penicillin epilepsy of the cat.

Previous studies had suggested that the epileptic bursts of feline generalized penicillin epilepsy represent the response of hyperexcitable cortex to thalamocortical volleys normally evoking spindles. If this were the case, it should be possible to convert the epileptic bursts of generalized penicillin epilepsy into spindles by decreasing the excitability of cortical neurons. In cats exhibiting the EEG signs of feline generalized penicillin epilepsy cortical excitability was decreased by hypoxia, by the topical application to the cortex of KCl (inducing spreading depression), barbiturates, GABA, AMP or noradrenaline. During generalized penicillin epilepsy, hypoxia and KCl-induced spreading depression abolished epileptic bursts which were replaced by spindles. When spindles and epileptic complexes occurring in the same animal were compared, a direct correlation between the frequencies of these two rhythms could be demonstrated, that of the epileptic complexes being about half that of the spindle waves. These observations support the hypothesis that the epileptic bursts of feline generalized penicillin epilepsy are induced by thalamocortical volleys normally involved in spindle genesis. Topical cortical applications of barbiturates, GABA, AMP and noradrenaline reduced or inverted the negative spikes of the spike and wave complexes, while augmenting the negative slow waves, or revealing them clearly in instances in which they had been poorly developed. This effect is interpreted as being due to a selective inactivation of the superficial cortical layers. That topical cortical application of barbiturates, GABA, AMP and noradrenaline was capable of transforming into typical spike and wave complex epileptic bursts, which had not previously conformed to this pattern, indicates that the intracortical electrophysiological events of typical and atypical epileptic bursts in feline generalized penicillin epilepsy are fundamentally the same and reflect an alternation between excitatory and inhibitory sequences.

Adenosine Monophosphate↗
PubMed1976

Generalization of morphine and lysergic acid diethylamide (LSD) stimulus properties to narcotic analgesics.

The present investigation sought to determine whether the stimulus properties of morphine and lysergic acid diethylamide (LSD) would generalize to several narcotic analgesics which vary in their subjective effects. Morphine and saline served as discriminative stimuli for one group of rats in a 2-lever discrimination task. LSD and saline were discriminative stimuli for a second group. Depression of one lever in an operant chamber resulted in reinforcement following the administration of morphine or LSD and the opposite lever was reinforced after saline. After discriminated responding was stable, stimulus generalization tests with narcotic analgesics and antagonists showed that the stimulus properties of morphine generalized to methadone and meperidine, and partially to pentazocine, all of which produce morphine-like subjective effects in humans. Morphine stimulus properties did not generalize to nalorphine or cyclazocine, which produce dissimilar subjective effects. The stimulus properties of LSD generalized partially to cyclazocine, but not to nalorphine. In humans cyclazocine and nalorphine produce a high incidence of psychotomimetic effects, but the subjective effects of cyclazocine are differentiable from those of LSD.

Analgesics, Opioid↗
PubMed2026

X chromosome-wide association studies for quantitative trait loci based on the mixture of general pedigrees and additional unrelated individuals.

Genome-wide association studies have successfully identified many genetic variants associated with complex traits. However, most existing methods target autosomes rather than X chromosome, and several existing X chromosome-wide association studies (XWAS) at quantitative trait loci (QTL) largely focus on unrelated individuals, with limited attention to general pedigrees or mixture of general pedigrees and additional unrelated individuals (called the mixed data for brevity). In this study, we propose nine novel methods for XWAS at QTL in the mixed data (${\mathrm{MQX}}_{\mathrm{cat}}$, ${\mathrm{MQZ}}_{\mathrm{max}}$, ${\mathrm{MT}}_{\mathrm{plinkw}}$, ${\mathrm{MT}}_{\mathrm{chenw}}$, $\mathrm{MwM}3\mathrm{VNA}$, ${\mathrm{MQMVX}}_{\mathrm{cat}}$, ${\mathrm{MQMVZ}}_{\mathrm{max}}$, $\mathrm{MpMV}$, and $\mathrm{McMV}$), also applicable to general pedigrees alone. The first four methods test for mean differences across genotypes; the latter four test for differences in both means and variances; $\mathrm{MwM}3\mathrm{VNA}$ tests for variance differences only. All mean-based and mean-variance-based methods incorporate X chromosome inactivation information, and all nine methods consider genetic relatedness in pedigrees. Simulation studies confirm well-controlled type I error rates, and inclusion of pedigrees significantly improves statistical power. Note that there has been no study focusing on X chromosome for the mixed data or general pedigrees from UK Biobank database, so we apply our proposed methods to this dataset, which identify five total cholesterol (TC)-associated and 13 low-density lipoprotein cholesterol (LDL-C)-associated single nucleotide polymorphisms (SNPs). Linkage disequilibrium (LD) analysis reveals that these SNPs fall into three distinct LD blocks. Functional annotation and gene ontology enrichment analysis reveal 16 and 28 enriched pathways for TC-associated and LDL-C-associated genes, respectively. These methods provide robust and powerful tools for XWAS at QTL in both mixed data and general pedigrees.

Quantitative Trait Loci↗
PubMed1978

Generalized epilepsy with bilateral synchronous spike and wave discharge. New findings concerning its physiological mechanisms.

A hypothesis for the mechanism of generalized spike and wave discharge in human generalized epilepsy is proposed in the light of findings obtained in feline generalized penicillin epilepsy. It is postulated that generalized bilaterally synchronous spike and wave discharge depends upon a diffuse and relatively mild state of cortical hyperexcitability which increases the responsiveness of cortical neurons. Afferent thalamo-cortical volleys normally involved in the genesis of spindles and recruiting responses are most likely to precipitate spike and wave discharges under these conditions. The spike and wave pattern probably results from the activation of a recurrent intracortical inhibitory pathway which becomes activated when cortical neurons discharge in greater number and more repetitively than is normally the case. During spike and wave discharges a large number of neurons oscillate between short periods of excitation, corresponding to the spike, and longer periods of inhibition, corresponding to the slow wave component of the spike and wave complex. This disrupts the normal transactional processes of cortical neurons which are presumably responsible for mental activity, particularly for the close integration of perception, cognition and voluntary motor responsiveness. The degree of this interference varies greatly and in mild absence seizure it is not justified to speak of "loss of consciousness". The fundamental disturbance in absence seizures brought about by the generalized cortical spike and wave discharges is therefore better regarded as a "clouding of the mind". Loss of consciousness can be said to occur only when the interference with mental activity becomes particularly intense. Loss of consciousness in absence seizures can therefore not be used as an argument in favor of primary involvement of higher brain-stem mechanisms.

Animals↗
PubMed1979

The effect of procaine hydrochloride and diazepam, separately or in combination, on cortico-generalized kindled seizures.

The effects of cortically kindled seizure responses of procaine hydrochloride, diazepam and combinations of these two drugs were tested in this study. The cortex was stimulated until seizure responses developed past the focal stage (accompanied primarily by brief tonic convulsions) to the cortico-generalized stage (accompanied, typically, by an early brief tonus followed by a longer clonic seizure that is characteristic of subcortically triggered seizures). Diazepam was found to block the generalized component of the cortico-generalized electrographic and motor seizure leaving the tonus only slightly suppressed. Procaine blocked the tonus leaving the clonic seizure and discharge that is characteristic of the generalized response relatively intact. Combinations of half doses of the two drugs completely blocked all electrographic and motor seizure responses in about half the animals. The remaining animals had a very brief discharge with no convulsive responses.

Animals↗
PubMed1975

General professional training in medicine.

A programme of general professional training in medicine based on the Royal Commission report has been in operation at the Western Infirmary, Glasgow, and associated hospitals since 1969. It involves a two-year rotation through general medicine, dermatology, psychiatry, paediatrics, geriatrics, and a variety of medical specialties. A third year is spent as far as possible in one unit of the doctor's choice. The scheme has been popular with trainees and senior staff. A high pass-rate has been achieved in the M.R.C.P.--23 out of 26 being successful within the three-year period. The trainees have subsequently taken up a wide variety of hospital posts within the broad division of medicine or entered general practice. The concept of a broadly based three-year period of general professional training in medicine has proved both practical and useful.

Curriculum↗
PubMed1976

Psychiatric screening in general practice. A controlled trial.

This study reports the efficacy of the General Health Questionnaire (G.H.Q.) in the secondary prevention of minor psychiatric illness in a primary-care setting. 1093 consecutive attenders at a general practitioner's surgery were screened for minor psychiatric disorder using the G.H.Q. 32% were found to have a conspicuous psychiatric disorder and a further 11% had a hidden psychiatric disorder. The group with hidden disorders were randomly assigned to a treated index group and an untreated control group. The effects of case detection and treatment were beneficial and immediate, with the duration of episode of the disorder being much shorter for patients whose disorder was recognised by the general practitioner. For patients with more severe disorders there are significant differences still demonstrable between the groups one year later; but patients with mild disorders do equally well, some recovering spontaneously but others becoming manifest to the general practitioner over the next year and so receiving treatment. The "detected" group of patients increased their consultations for emotional complaints over the next year, but their total consultation-rate was not increased.

Clinical Trials as Topic↗
PubMed1979

A comparison of essential and general amino acid infusions in protein-depleted patients receiving parenteral alimentation.

Six malnourished patients were studied during intravenous nutrition therapy to compare the efficiency of essential and general amino acids when given as the sole nitrogen source during intravenous nitrogen therapy. A cross-over design was used so that each patient received both essential amino acids plus arginine and histidine and a general amino acid solution in random order. Glucose provided the remainder of the energy and both infusions contained 2 g of amino acid per 100 kcal. Each patient's daily urea nitrogen production was greater during infusion of the general amino acid solution. Consequently, nitrogen intake minus urea nitrogen production was significantly greater when the essential amino acid solution was infused. Plasma amino acid levels were determined on each patient during both essential and general amino acid infusion. Abnormalities tend to reflect the composition of the amino acid solutions as well as their administration directly into the systemic circulation bypassing the portal circulation.

Adult↗
PubMed1975

General practitioners and social help for the handicapped.

A study was undertaken by the Greater London Association for the Disabled in consultation with the Royal College of General Practitioners, to explore the depth of knowledge of the Chronically Sick and Disabled Persons Act and statutory and voluntary social provision, of 22 general practitioners in 16 practices served by one area social services office in a London borough.The doctors were mainly middle-aged, of British or Irish birth and training and had no language barrier. The majority lived in or near their practices. Half the practices were groups or partnerships, half were singlehanded. Only in three groups was there any attached district nursing staff and in only one was there an attached health visitor. More than half the general practitioners had reception staff only during surgery hours. Four practices had no reception staff during National Health Service surgery hours, two of which had no reception staff at all. In no practice was there any privately employed nursing staff. All the practices had private patients.Nine of the 22 doctors in the study had never heard of the Chronically Sick and Disabled Persons Act, and a further five had not mentioned the Act to their patients. Fifty per cent had no knowledge of the extent of functional disability in their practice. More than half the doctors knew no more of the social services than that home helps and meals-on-wheels were available, while six doctors knew of no provision at all. Knowledge and use of the voluntary services was almost non-existent. No meetings with team members were held, other than in the group practices with attached staff, and the team members were largely unknown to most of the doctors.Attempts were made through various channels to extend the knowledge of the general practitioners of the services provided by both statutory and voluntary agencies, and to introduce them and their receptionists to their team, but little use was made of the opportunity.

Adolescent↗
PubMed2026

Comparison of the Effects of Spinal Versus General Anesthesia on the Perioperative Intraocular Pressure: A prospective, randomized clinical trial.

OBJECTIVES: To evaluate the effects of spinal and general anesthesia on the intraocular pressure (IOP) in patients, who had lumbar spine and lower extremity orthopedic surgeries. METHODS: Sixty adult were randomly classified into Group spinal anesthesia (SA) and Group general anesthesia (GA). The IOP, mean systemic arterial pressure, and heart rhythm were measured at 6 pre-determined timepoints (T0: Baseline, T1: Before spinal procedure or anesthesia induction, T2: After injection with intrathecal or anesthesia induction, T3: 5th minutes (min) after spinal procedure or tracheal intubation, T4: 30th min intraoperative, T5: At the end of surgery, T6: 5th min after surgery or tracheal extubation in the operation room. RESULTS: The baseline IOP and IOP1 measurements during were not significantly different between the groups (SA = 14.28 &#xb1; 0.8 mmHg; GA = 14.62 &#xb1; 0.9 mmHg, p = 0.923; and IOP1: SA = 15.83 &#xb1; 0.9 mmHg; GA = 15.88 &#xb1; 0.9 mmHg, p = 0.929). The most significant decrease in IOP in both groups was recorded at T2 (SA: 12.37 &#xb1; 0.6. GA: 12.24 &#xb1; 0.4, p < 0.001). The decrease in IOP2 was more significant in the GA group. The IOP3 was significantly higher in GA group after intubation (GA: 19.82 &#xb1; 1.2, SA: 12.86 &#xb1; 1.0)(p < 0.05). The IOP4 and IOP5 in the SA group were lower than those in the GA group. The IOP6 in both groups was higher (SA: 15.20 &#xb1; 0.8, GA: 16.50 &#xb1; 1.0) than the baseline IOP values, albeit not significant (p > 0.05). In prone position, IOP at the T4 and T5 timepoints were significantly higher than the initial values in both the SA and the GA groups; however, the increase in the GA group was more higher than that of the SA group. CONCLUSION: In intraoperative period, intraocular pressure may increase in both management of anesthesia, but this increase is higher in the general anesthesia group.

Humans↗