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PubMed2003

Up-regulated gene expression in the conjunctival epithelium of patients with Sjögren's syndrome.

PURPOSE: To elucidate the pathogenesis of ocular surface abnormalities in patients with Sjögren's syndrome (SS) by comparing global gene expression patterns in conjunctival epithelial cells from normal individuals and SS patients. METHODS: The study population consisted of 56 subjects (26 SS patients and 30 normal volunteers). RNA extracted from their conjunctival epithelial cells was subjected to introduced amplified fragment length polymorphism (iAFLP), a competitive PCR-based gene expression assay, to measure gene expression in the 56 samples against 931 genes. Data were analyzed by two-dimensional clustering analysis and discriminant analysis. Disease-related genes were identified and the feasibility of gene expression-based diagnosis of SS was examined. RESULTS: Two-dimensional clustering- and discriminant analysis clearly distinguished between SS patients and normal subjects. Of 931 genes tested, 34 were significantly up-regulated and 12 were significantly down-regulated in SS (p<0.05). Up-regulated genes included kallikrein 7 (x 15.8) and small proline-rich protein 2A (x 9.6), markers for the terminal differentiation of epidermis, and the inflammation-related genes HLA-DR and IL-6. Monokine-induced-by-gamma-interferon, i.e. c-fos, fibronectin, amphiregulin, defensin beta 2, and keratin 16, -6b and -6c were also up-regulated. Among the 12 down-regulated genes, interferon-gamma receptor 1 was most notable (x1/27.3). CONCLUSIONS: The up-regulated expression of keratin 6 and -16, small proline-rich protein 2A, and kallikrein 7 in the conjunctival epithelium of SS patients suggests an anomalous keratinization pattern. Epithelial thickening may be due to amphiregulin and/or c-fos-stimulated cell cycle progression. The up-regulation of monokine-induced-by-gamma-interferon, HLA-DR, keratin 6b, -6c, and -16 suggests that in SS, interferon-gamma may play an important role in the altered gene expression in the conjunctival epithelium.

Aged↗
PubMed2006

[Wavefront analysis for the diagnosis of subclinical keratoconus].

BACKGROUND: The entity of subclinical keratoconus (SKC) has not been defined sufficiently yet. The aim of the study was to describe ocular wavefront aberrations of clinically inconspicuous fellow eyes in patients with early keratoconus (KC) as a model of SKC and to assess the feasibility of higher-order wavefront analysis to discriminate eyes with SKC from normal eyes. METHODS: This prospective study included eight clinically inconspicuous fellow eyes of eight patients with newly detected KC in the contralateral eye and a paracentral inferior-superior difference (PISD) <1.4 D. In total, 15 eyes of 12 patients with newly diagnosed KC and a PISD >1.4 D were included as positive controls and 71 healthy eyes of 40 patients served as negative controls. The wavefront error was measured in all eyes with a Hartmann-Shack sensor. Discriminant analysis was performed with input from ocular HOA data and PISD. Receiver operating characteristic (ROC) curves were plotted for PISD, single Zernike coefficients, and for the output values of the discriminant functions to investigate their usefulness for discrimination between SKC eyes, early KC eyes, and healthy controls. RESULTS: There were significant differences between inconspicuous fellow eyes (group 2) and controls (group 3) for PISD, for the coefficients Z3(-3), Z3(-1), Z4(0) and Z5(-1), and for the output values of the discriminant functions. The latter discriminated between groups 2 and 3 with maximum sensitivity and specificity (A(z) ROC=1), whereas discriminative ability was considerably lower for single Zernike coefficients. CONCLUSION: Single Zernike coefficients did not appear to be useful for the detection of SKC. Using discriminant analysis, from PISD and higher-order Zernike coefficients a metric with very high discriminative ability between normal and SKC eyes could be constructed.

Adult↗
PubMed2005

Classifying genomic sequences by sequence feature analysis.

Traditional sequence analysis depends on sequence alignment. In this study, we analyzed various functional regions of the human genome based on sequence features, including word frequency, dinucleotide relative abundance, and base-base correlation. We analyzed the human chromosome 22 and classified the upstream, exon, intron, downstream, and intergenic regions by principal component analysis and discriminant analysis of these features. The results show that we could classify the functional regions of genome based on sequence feature and discriminant analysis.

Algorithms↗
PubMed2004

Multivariate statistical techniques for the evaluation of spatial and temporal variations in water quality of Gomti River (India)--a case study.

This case study reports different multivariate statistical techniques applied for evaluation of temporal/spatial variations and interpretation of a large complex water-quality data set obtained during monitoring of Gomti River in Northern part of India. Water quality of the Gomti River, a major tributary of the Ganga River was monitored at eight different sites selected in relatively low, moderate and high pollution regions, regularly over a period of 5 years (1994-1998) for 24 parameters. The complex data matrix (17,790 observations) was treated with different multivariate techniques such as cluster analysis, factor analysis/principal component analysis (FA/PCA) and discriminant analysis (DA). Cluster analysis (CA) showed good results rendering three different groups of similarity between the sampling sites reflecting the different water-quality parameters of the river system. FA/PCA identified six factors, which are responsible for the data structure explaining 71% of the total variance of the data set and allowed to group the selected parameters according to common features as well as to evaluate the incidence of each group on the overall variation in water quality. However, significant data reduction was not achieved, as it needed 14 parameters to explain 71% of both the temporal and spatial changes in water quality. Discriminant analysis showed the best results for data reduction and pattern recognition during both temporal and spatial analysis. Discriminant analysis showed five parameters (pH, temperature, conductivity, total alkalinity and magnesium) affording more than 88% right assignations in temporal analysis, while nine parameters (pH, temperature, alkalinity, Ca-hardness, DO, BOD, chloride, sulfate and TKN) to afford 91% right assignations in spatial analysis of three different regions in the basin. Thus, DA allowed reduction in dimensionality of the large data set, delineating a few indicator parameters responsible for large variations in water quality. This study presents necessity and usefulness of multivariate statistical techniques for evaluation and interpretation of large complex data sets with a view to get better information about the water quality and design of monitoring network for effective management of water resources.

Data Collection↗
PubMed2003

3D-MEDNEs: an alternative "in silico" technique for chemical research in toxicology. 1. prediction of chemically induced agranulocytosis.

A novel approach to molecular negentropy from the point of view of Markov models is introduced. Stochastic negentropies (MEDNEs) are used to develop a linear discriminant analysis. The discriminant analysis produced a set of two discriminant functions, which gave rise to a very good separation of 93.38% of 151 chemicals (training series) into two groups. The total predictability (86.67%, i.e., 52 compounds out of 60) was tested by means of an external validation set. Randić's orthogonalization procedures allowed interpretation of the model while avoiding collinearity descriptors. On the other hand, factor analysis was used to suggest the relation of MEDNEs with other molecular descriptors and properties into a property space. Three principal factors (related to three orthogonal MEDNEs) can be used to explain approximately 90% of the variance of different molecular parameters of halobenzenes including bulk, energetic, dipolar, molecular surface-related, and hydrophobic parameters. Finally, preliminary experimental results coincide with a theoretical prediction when agranulocytosis induction by G-1, a novel microcidal that presents Z/E isomerism, is not detected.

Agranulocytosis↗
PubMed1977

Cooperative study of hospital frequency and character of transient ischemic attacks. V. Symptom analysis.

All patients (1,328) suspected of having transient ischemic attacks (TIA) who came to six institutions during a 21-month period were identified. Symptoms and symptom complexes were related to the clinical diagnoses by cross-tabulation, factor analysis, and discriminant analysis. The diagnoses obtained by the discriminant analysis program were comparable to those of reviewing clinical neurologists. Symptoms of importance in the vertebral-basilar system (VBS) were bilateral visual blurring, diplopia, ataxia, and dizziness; In either carotid system (CAS), ipsilateral monocular visual disturbance anc contralateral weakness or sensory complaints; in the left CAS, language disturbances; and in those whose ultimate diagnosis was not TIA, loss of consciousness, confusion, and bilateral leg weakness. Patients with VBS TIAs have symptoms common to conditions that are not TIA and have a greater variety of symptoms and more combinations of symptoms than CAS TIA.

Aphasia↗
PubMed2001

Functional classification of patients with idiopathic scoliosis assessed by the Quantec system: a discriminant functional analysis to determine patient curve magnitude.

STUDY DESIGN: A stepwise discriminant analysis was used to define a spinal deformity score based on three-dimensional measurements by the Quantec spinal image system (raster stereophotograph). OBJECTIVE: To provide functional classification of spinal deformity in patients with mild idiopathic scoliosis without using radiographs. SUMMARY OF BACKGROUND DATA: Most studies classify the degree of spinal deformity in terms of coronal plane radiograph without analyzing transverse rotation. To the authors' knowledge, no studies investigating classification of spinal deformity in idiopathic scoliosis using Quantec system measurements have been documented. METHODS: In this study, 129 patients with a single curve and 119 patients with a double curve were divided into three groups according to Cobb angle: Group 1 (less than 10 degrees ), Group 2 (10-20 degrees ), and Group 3 (greater than 20 degrees ). RESULTS: The patients were assigned to the group with the highest scores after application of a stepwise discriminant analysis. The accuracy of the classification system by functional scores for the patients with a single curve was 85% for Group 1, 63.5% for Group 2, and 71.7% for Group 3. The accuracy of classification by functional scores for the patients with a double curve was 87.1% for Group 2 and 76.1% for Group 3. CONCLUSION: The back surface image study is a method for providing a quantitative assessment of mild spinal deformity, allowing evaluation of patients by integrated three-dimensional parameters with no reference to radiographs.

Adolescent↗
PubMedDate not supplied

Spatial patterns of anthropometric variation in India with reference to geographic, climatic, ethnic and linguistic backgrounds.

BACKGROUND: Anthropometric variation can be fruitfully utilized to investigate microevolutionary processes. Anthropometric variations in the Indian subcontinent based on stature and three indices (Cephalic Index, Nasal Index, and Total Facial Index) are highly variable and discriminative among populations across geographical regions. AIMS: Anthropometric variation in stature, Cephalic Index (CI), Nasal Index (NI) and Total Facial Index (TFI) were investigated with respect to ethnic, linguistic, geographical and climatic affiliation, across the Indian subcontinent. SUBJECTS AND METHODS: Published data on anthropometric variations of 531 populations from the Indian subcontinent were analysed using discriminant analysis and spatial autocorrelation analysis. RESULTS: Discriminant analysis of the four anthropometric variables shows that stature and NI are good discriminators for populations of different languages. Stature, NI and CI discriminate well among populations of diverse ethnic origin and climatic conditions in different regions. TFI is not a good discriminator for populations of diverse ethnic, linguistic and climatic attributes. Spatial autocorrelation analysis showed significant departure from randomness, suggesting geographic structuring. The Moran's I estimate is positive and statistically significant for the four variables at low distances but exhibits significant negative association at higher values. CONCLUSION: The results suggest geographical clines for the four anthropometric variables and indicate the influence of population structure on the studied variables.

Analysis of Variance↗
PubMedDate not supplied

Computer-supported analysis (MegaBlot) of allopurinol-induced changes in the autoantibody repertoires of rats suffering from experimental lens-induced uveitis.

Using a new quantitative immunoblot technique (MegaBlot and artificial neural network) sera of rats with lens-induced uveitis (LIU) were tested against Western blots (WB) of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) separations of protein fractions from rat lenses. The blots were scanned using digital image analysis and evaluated by multivariate analysis of discriminance and an artificial neural network. Five groups of LIU rats (male Wistar rats, n = 28) were investigated: no treatment, single doses of methylprednisolone (MPR; 7.5 mg/kg body weight, intravenous), allopurinol (AL; 50 mg/kg body weight, intravenous), a combination of both drugs (AL and MPR), and repeated application of AL (ALFR; 50 mg/kg body weight intravenous every 2 weeks during the immunization period and a daily dose of approximately 25 mg/kg body weight, orally). ALFR, MPR, and MPRAL show statistically significant immunological effects in LIU treatment. Classification of WBs using both discriminance analysis or neural network resulted in 100% correct assignment; and 82% (discriminance analysis) and 86% (neural network) of WBs were correctly assigned using only unknown blots for classification (not studied before). The MegaBlot technique is able to detect therapeutically induced changes in autoantibody repertoires allowing therapeutic control and a prognostic view of treatment.

Allopurinol↗
PubMed2005

Research on adverse drug events. I. Muscarinic M3 receptor binding affinity could predict the risk of antipsychotics to induce type 2 diabetes.

Antipsychotics are associated with a wide range of adverse effects, several of which may represent a serious health risk to patients. There is an increased concern about metabolic disturbances associated with antipsychotics, including weight gain, dyslipidemia, hyperglycemia, and type 2 diabetes. However, little is known about the mechanisms underlying antipsychotic-induced metabolic disturbances and, in particular, those related to the induction of abnormal glucose metabolism and diabetes. The present article aimed to identify those receptor(s) that are most likely to be involved with or mediate antipsychotics-induced diabetes. Two independent measures taken from literature to indicate the risk of type 2 diabetes associated with 25 typical and atypical antipsychotic drugs were considered, along with their binding affinities to 21 specific receptors (obtained from the resources of Prous Science Integrity). A range of both exploratory and predictive statistical analyses were applied, including principal component factorial analysis, multivariable linear regression analysis, and discriminant analysis. Binding affinities (pKi) to human neurotransmitter receptors and monoaminergic transporters were used as independent variables (predictors). Measures to determine the risk to induce new-onset type 2 diabetes associated with each antipsychotic, logistic regression odds-ratio (dOR) and a discrete scale-based risk (three levels: 'low,' 'moderate,' 'high'), were used as the dependent variables (criteria). Similarly, parallel analyses were also conducted for other measures (average effective therapeutic dose) or adverse effects (weight gain, extrapyramidal side effects, hyperprolactinemia, anticholinergic, hypotension, and sedation) associated with antipsychotics, where underlying mechanisms have been previously established and, therefore, serve as positive-control references. Affinity for the cholinergic muscarinic M3 receptor subtype was presented as the best predictor for the propensity of antipsychotics to induce type 2 diabetes. This was independently revealed by means of multiple linear regression analysis, using the dOR as criterion (R=0.90, p<0.0001), and discriminant analysis, using the scale-based risk of type 2 diabetes (3 levels) as criterion (Wilks' lambda=0.33, chi2=14.11, p<0.001). To our knowledge, this study provides the first direct evidence to indicate that antipsychotic agents with high binding affinity to the muscarinic M3 receptor are associated with an elevated risk for type 2 diabetes. Rationale of the M3 receptor involvement in this adverse effect is discussed further in relation to M3 receptor mediation of glucose-dependent parasympathetic acetylcholine regulation of insulin secretion by pancreatic beta-cells. This study is the first in a series of investigations that aim to further our understanding of mechanisms underlying adverse drug effects.

Antipsychotic Agents↗
PubMed1983

[Early exercise test after myocardial infarct: prognostic stratification].

Exercise testing in myocardial infarction before discharge has been used for treatment and exercise prescription in the post-hospital phase. Aim of this study was to investigate the prognostic significance, within one year after the infarction, of submaximal exercise testing before discharge. 428 patients performed the test 14.5 days after the acute episode and were followed for 12 months. The following variables were examined: heart rate, blood pressure, rate-pressure product at maximum exercise, total work and reasons for stopping the test (fatigue, submaximal HR, BP greater than or equal to 200/110, hypotension, ischemic or arrhythmic response). Two events were considered: 1) non fatal reinfarction; 2) cardiac death. Two methods of multivariate analysis (Cox's model regression analysis and discriminant analysis) were used. None of the considered variables was found to be predictive of non fatal reinfarction. According to Cox's model total performed work and hypertensive response were found to be predictive of cardiac death, while using discriminant analysis only total work had a predictive value (discriminant function: L = 0.00094 X total work performed + 1.48643; p less than 0.01). In detail, the higher the total work, the better the probabilities of survival, while in patients who stopped the test because of hypertension, the probabilities of cardiac death were lower. Exercise testing performed in uncomplicated myocardial infarction before hospital discharge provides, the basis for a more rational management of patients in the post-infarction phase, and contributes to identify a subset of high-risk patients.

Aged↗
PubMed1996

[Attitudes, beliefs, and motivations in blood donors and non-donors].

OBJECTIVE: To know and compare the beliefs, attitudes and motivations of donors and non-donors in relation with blood donation. MATERIAL AND METHODS: Transversal study by questionnaires administered to 197 blood donors and 303 non-donors. The questionnaires gathered: sociodemographic data, beliefs and attitudes (using a Likert scale), and motivations and demotivations (using upon questions). The responses were analysed using different descriptive analyses and bivariant tests, and factorial analysis and discriminant analysis were performed as multivariant analyses. RESULTS: The donor group had a mean age of 37.8 years, were 58.4 female and 41.6% male, and had made 6.02 donations. The non-donor group had a mean age of 39.8 years and were 53.8% female and 46.2 male. Regarding attitudes and beliefs, the donor group showed more confidence in the good conditions in which donations are performed, had less fears about the possibility that donation can affect health, their attitudes were generally less egotistical, and they had less fears about possible commercialisation of the blood. Both groups believed that blood banks and society itself give inadequate compensation to donors, but this belief was significantly greater among non-donors. Regarding the motivations of donors, the highest proportion were related with a sense of solidarity or duty (26.4%), followed by issues related with information or pressure (23.4%), and the possible personal or family benefits that donation might bring (21.8%). The initial motivations of most donors (75.9%) had not varied with the passage of time, and the factors found to be most demotivating for donation had to do with problems of access and comfort (74.6%). We would highlight that most non-donors denied any worries about blood donation (70.9%) and did not agree that those who need blood should be those who pay for it (92.8%). For non-donors, lack of information (43.6%) and different fears (32.3%) were the principal factors discouraging them from donating. Finally, discriminant analysis selected 11 of the items as providing 75.6% of correct discrimination between the one population and the other. CONCLUSIONS: Donors and non-donors reveal very different beliefs, attitudes and motivations towards blood donation, and the questionnaire employed in this study permits a high degree of discrimination between the two groups. The attitudes of non-donors towards donation are generally less favourable, but allow us to think that a high percentage of these could be changed with the right conditions.

Adult↗
PubMed1986

[Results of experimental gerontology with respect to biological age].

Biological age may be defined as the state of the organism as a whole which is characteristic of the respective chronological age. Objective estimates of biological age are usually obtained by multiple regression analysis of a greater number of age parameters. However, this procedure should be based on a firm knowledge of the regularities of multicellular ageing. By means of a long-term study in male rats regularities of biological ageing have been demonstrated using multiple regression analysis, factor analysis and discriminant analysis. The multiple regression model pointed to an exponential relation between chronological and biological age. By factor analysis it has been shown that the change of the parameters represents to various extents primary ageing and system-specific secondary ageing. The results of discriminant analysis reveal a change in the ageing pattern during senescence. Consequently, test batteries for the objectivation of influences on the rate of ageing should be adapted to the respective phase of ageing in order to obtain maximum sensitivity.

Aging↗
PubMed1999

[The autonomization of public hospitals and its consequences on health care demands, Lima, 1988-1997].

Between 1988 and 1992 public hospitals in Peru were affected by major changes: the operational collapse of the health services, a profound State budgetary crisis, and a series of adjustments aimed toward self-financing. These changes all came before the health sector reform laws of 1997. In recent years, the changes in financing policy have renewed the operational potential of hospital activity and of the entire health sector. On the other hand, there have been some signs that with hospitals generating their own resources through fee collection, there has been a shift in the proportion of hospital users from different socioeconomic strata, to the detriment of poorer persons, especially those who need free services. This study tried to determine if there had been such changes between 1988 and 1997 in the socioeconomic strata of persons using five large public hospitals in Lima, and the association that that could have with the current transition toward the new model of the autonomous hospital, particularly with the new policies on hospital financing. Changes in hospital usage were studied through in-depth interviews with key informants, collection of statistical data in the selected hospitals, and an extensive bibliographic and literature review. Changes in hospital usage were studied through 1,012 surveys done with hospital users from the years 1988, 1992, and 1997. In order to classify those persons by socioeconomic stratum, cluster analysis and discriminant analysis were used, based on six variables suitable for determining socioeconomic level. The resulting model, of three strata grouped according to the dichotomized variables, exceeded the 75-point minimum required for the discriminant analysis to confirm the classification test. The main results showed that among the users of the five Lima hospitals, those in the highest stratum increased their relative use of the hospitals from 35.4% in 1988 to 52.6% in 1997. Proportional usage by those in the lowest stratum declined in the same period, from 25.4% to 20.5%. Usage by those in the intermediate stratum also declined, from 39.2% to 26.8%. It is clear that the trend in hospital financing has been toward an increase in user copayments, with public funding making up a smaller proportion of hospital budgets. This study verifies the results found in the 1991 and 1994 National Surveys of Standards of Living, which showed that the proportion of hospital usage by "poor" persons declined from 37.3% to 34% between 1991 and 1994 and that usage by persons above that "poor" economic level increased from 34.8% to 43.8%. The authors conclude that without a holistic approach to reform, microreforms produce both microefficiency and systemic inequity. In those circumstances, output and yield become more important than the impact and effectiveness of services for the population served.

Health Services Needs and Demand↗
PubMed2000

Analysis of the flow patterns of liquid organic compounds between blade electrodes by classification models

The flow patterns of 20 organic liquids with diverse structures and functionalities between electrodes were measured under a dc electric field. The results clearly showed the existence of a strong relationship between the flow pattern of a compound and its molecular structure. On the basis of a variety of 23 molecular descriptors including those obtained by quantum-chemical calculations, multiple regression analysis and discriminant analysis were applied to identify the significant factors contributing to the flow patterns. For the flow rate dipole moment, nucleophilic delocalizability and lipophilicity as expressed by the 1-octanol/water partition coefficient were found to be the key factors as judged by a five-value regression model with a squared correlation coefficient (r2) of 0.881. For the direction of the flow, just two quantum-chemical parameters, namely, absolute hardness and the self-polarizability normalized by molecular volume, were identified as significant factors by using linear discriminant analysis. The numbers of misclassified compounds were only one and two for training and prediction (leave-one-out cross-validation), respectively, by the best discriminant model.

Journal Article↗
PubMedDate not supplied

[The AMDP scales in a phase II evaluation of psychotropic drugs].

Four multicentre double blind trials (two studies comparing placebo to a marketed activating drug and two comparing placebo to a new drug with central adrenergic modulating properties) were pooled, totalling 77 placebo Ss, 30 reference drug Ss and 73 study drug Ss. The AMDP-4 and -5 scales were filled out at day 0 and 7 by trained raters. Four statistical analyses were performed on the pre- vs. postdrug differences: an analysis of variance, a principal components factor analysis, a discriminant analysis and a cluster analysis. The results indicate that 9 out of the 14 AMDP factor scores significantly decrease within 1 week while the factor Mania-Agitation increases, without differences between both active compounds; on the item level, the "inhibition of drive" is specifically improved by the study drug; the discriminant analysis confirms that the two most improved items are "Inhibition of drive" and "Hopelessness". Three factor scores significantly improve on placebo (Depression, Retardation, Psycho-organic Symptoms), which points to the necessity of placebo-controlled studies in clinical trials of new drugs.

Double-Blind Method↗
PubMed1991

[The clinical significance of multifactor discrimination and analysis of maternal serum Cu, Zn, Cd, Mn contents in the diagnosis of abnormal fetus].

In this paper we present pair-comparison test with serum contents of Cu, Zn, Cd, Mn, Se in pregnant women with neural tube defects fetus (NTD), pregnant women with normal fetus and healthy with no pregnancy using Bayes Stepwise Discrimination Analysis and Fisher Discrimination Analysis. The results showed: NTD of fetus was related to deficiency of maternal serum in Cu, Zn, Mn and to excess of Cd. The maternal serum levels of Cu, Cd and Mn can be used as sensitive indicator to detect intrauterine abnormality at an early stage. The low levels of maternal serum in Zn and Se were not a specific indicator of NTD but a characteristic shared by all pregnant women. It is important to pay attention to supplying pregnant women at an early stage with Zn, Se to meet the needs of normal growth of the fetus and prevent foetal abnormality. With stepwise discrimination we established two equations by Cu, Zn, Cd, Mn used for distinguishing normal from abnormal fetus. The accordant rate of clinical discrimination with classification output for inside examples was 93%. In the equation established by Fisher principle Mn had the greatest rate, namely, 37.6%.

Adult↗
PubMed1989

Cortical EEG changes during the self-administration of phencyclinoids.

Female rats, implanted with cerebrocortical EEG recording electrodes, were trained to self-administer cocaine and then ketamine under a fixed ratio 10 schedule of reinforcement, during limited access sessions. Periodically, a single unit dose of either phencyclidine (0.5 mg/kg), ketamine (4 mg/kg) or 1-(1-phenylcyclohexyl)morpholine (PCM 4 mg/kg) was substituted for ketamine, while the cortical EEG was recorded. Spectrum quantities of samples of EEG, taken immediately before and after each injection, were subjected to a discriminant analysis. For each drug, the preinjection state of the EEG could be classified separately from the postinjection state, using specific EEG spectrum quantities from the global frequency range (0.1-20 Hz). Furthermore, the relevant EEG parameters, which described the change from pre- to postinjection states, were unique for each drug (phencyclidine: total power and complexity; ketamine: peak frequency, relative power and mobility; PCM: all parameters except peak frequency), indicating potential differences in the EEG, occurring with a level of intake of drug which was controlled by the subject. Overall, these data serve to model the changes in the EEG that occur during the self-administration of three phencyclinoids. Furthermore, the combination of EEG spectrum analysis with discriminant analysis is useful in detecting subtle differences in the effects of these three drugs on the EEG.

Animals↗