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PubMed2006

Multivariate perspectives on change and continuity in the Middle Stone Age lithics from Klasies River Mouth, South Africa.

This paper examines variability and the emergence of the Howiesons Poort within the Middle Stone Age lithic technologies of Klasies River Mouth. Here I present a pattern recognition study using multivariate statistical techniques examining the data presented by [Singer, R., Wymer, J.J., 1982. The Middle Stone Age at Klasies River Mouth in South Africa. Chicago University Press, Chicago]. Using this model, the Middle Stone Age (MSA) lithics from Klasies River Mouth load on three main factors: (1) a Levallois flake manufacture factor, (2) a blade manufacture factor, and (3) a worked point factor. The MSA I assemblage from Cave 1 and the MSA II assemblage from Shelter 1a correlate strongly with the worked point factor, the MSA II assemblage from Cave 1 correlates strongly with the Levallois factor, and the Howiesons Poort assemblage from Shelter 1a correlates strongly with the blade factor. The Howiesons Poort from Shelter 1a is differs more from all other industries than the remaining industries do from each other. In addition, the Howiesons Poort from Cave 2 groups closely with the MSA III assemblage from Shelter 1a due to similarities in raw material frequencies.

Archaeology↗
PubMed1992

Systematics of the Saguinus oedipus group of the bare-face tamarins: evidence from facial morphology.

The systematics of the Saguinus oedipus group within the bare-face tamarins remains open to question. Hershkovitz (Living New World Monkeys (Platyrrhini), Vol.1. Chicago: University of Chicago Press, 1977) places the cotton-top and rufus-naped tamarins as subspecies of Saguinus oedipus (S. o. oedipus and S. o. geoffroyi, respectively). In contrast, several other authors have argued that these two taxa should be considered separate species (S. oedipus and S. geoffroyi). Phylogenetic relationships within the group are also disputed. Resolving these different interpretations has been difficult in part because no study of this group has included an objective measure of expected levels of specific vs. subspecific variation. We used facial measurements from 179 adult crania to address the systematics of this group and included a related species that is known to include multiple subspecies. Our sample included three taxa from the S. oedipus group of the bare-face tamarins (S. oedipus, S. geoffroyi, and S. leucopus) and six subspecies from the related hairy-face tamarin species S. fuscicollis. Comparisons to S. leucopus provided a relative measure of species-level differences. Analyses that included S. fuscicollis provided a measure of subspecific variation. There was no evidence of facial sexual dimorphism in any of these taxa. A variety of multivariate statistical analyses including discriminant function and cluster analysis suggest that S. oedipus and S. geoffroyi differ morphologically at a level consistent with species-level distinctions. The extent of differences between these taxa is large. The differences in their facial morphology was on the order of differences between S. oedipus or S. geoffroyi and S. leucopus rather than the extent of variation among S. fuscicollis subspecies. Furthermore, a comparison of collecting localities revealed that the variation we observed among S. oedipus and S. geoffroyi was not clinical but presented a large morphological discontinuity at the boundary between taxa. Our analyses also suggested that S. leucopus is more similar to S. oedipus than is either to S. geoffroyi. Finally, it may be that there are some distinct species within the S. fuscicollis group. However, this hypothesis, along with other phylogenetic relationships suggested by this study, will require more data and further study.

Animals↗
PubMed1991

Predictors of functional outcome and resource utilization in inpatient rehabilitation.

Consecutive patients (n = 1,289) discharged from two inpatient rehabilitation facilities were prospectively examined to determine the extent to which rehabilitative outcomes, functionally based progress, and associated resource utilization (in terms of rehabilitation length of stay) can be concomitantly predicted using the Tufts/New England Medical Center functional assessment tool and bivariate and multivariate statistical comparisons. A high percentage (greater than 50%) of statistically significant associations between the predictor variables and seven outcome measures were seen. The R2s corresponding to these associations were generally small and resistant to enhancement by commonly accepted statistical manipulations. Consequently, they are, in general, of limited predictive value for determining functional prognosis or resource utilization among rehabilitation inpatients. Although functionally based predictors appear to be the best predictors of functional progress, their effectiveness as predictors of other domains (eg, discharge outcome and rehabilitation length of stay) is variable. The implication is that a prospective payment system using such an array of predictors and directed primarily at cost containment is likely to overlook potentially important gains in functional progress and patient outcome. Furthermore, the functionally based predictors, taken individually, varied in effectiveness as predictors among facilities, and, taken collectively, they varied in effectiveness as predictors for different diagnostic groupings within a facility. The inconsistency of predictions according to the various domains appears to further limit their application to a prospective payment model.

Activities of Daily Living↗
PubMed2003

Improving structure-based virtual screening by multivariate analysis of scoring data.

Three different multivariate statistical methods, PLS discriminant analysis, rule-based methods, and Bayesian classification, have been applied to multidimensional scoring data from four different target proteins: estrogen receptor alpha (ERalpha), matrix metalloprotease 3 (MMP3), factor Xa (fXa), and acetylcholine esterase (AChE). The purpose was to build classifiers able to discriminate between active and inactive compounds, given a structure-based virtual screen. Seven different scoring functions were used to generate the scoring matrices. The classifiers were compared to classical consensus scoring and single scoring functions. The classifiers show a superior performance, with rule-based methods being most effective. The precision of correctly predicting an active compound is about 90% for three of the targets and about 25% for acetylcholine esterase. On the basis of these results, a new two-stage approach is suggested for structure-based virtual screening where limited activity information is available.

Acetylcholinesterase↗
PubMedDate not supplied

Risk factors for alcohol use during pregnancy in a multistate area.

A substance use screening instrument was used to select persons into two risk categories for drinking during pregnancy. About one-fourth (23.8%) of the survey participants were classified as high-risk women and the others were classified as low risk for drinking when pregnant. The participants (N=4676) for the study were sampled from four states (Montana, Minnesota, South Dakota, and North Dakota) that are a part of the Four-State Fetal Alcohol Syndrome (FAS) Consortium. Clinic sites for the administration of the prenatal screening instrument were selected in each state, based on geographic and known population characteristics. Univariate and multivariate statistical procedures were used to determine factors predictive of alcohol use. The purpose of the study was to assess risk factors for alcohol use in pregnant women. Women at high risk for alcohol use when pregnant tended to be younger, less educated, single, and unemployed. Demographic factors that were protective of drinking when pregnant were being married and full-time housewife status. Other variables associated with high-risk status for maternal alcohol use were past sexual abuse, current or past physical abuse, using tobacco, using other drugs, living with substance users, and having mates who were substance users. Other contributing factors for high-risk classification included feeling sad, believing that drinking any amount of alcohol while pregnant was acceptable, and being able to hold four or more drinks. Intervention programs that ameliorate risk factors and enhance protective attributes of high-risk pregnant women are needed.

Adolescent↗
PubMed2006

Metabolic profiling reveals a contribution of gut microbiota to fatty liver phenotype in insulin-resistant mice.

Here, we study the intricate relationship between gut microbiota and host cometabolic phenotypes associated with dietary-induced impaired glucose homeostasis and nonalcoholic fatty liver disease (NAFLD) in a mouse strain (129S6) known to be susceptible to these disease traits, using plasma and urine metabotyping, achieved by (1)H NMR spectroscopy. Multivariate statistical modeling of the spectra shows that the genetic predisposition of the 129S6 mouse to impaired glucose homeostasis and NAFLD is associated with disruptions of choline metabolism, i.e., low circulating levels of plasma phosphatidylcholine and high urinary excretion of methylamines (dimethylamine, trimethylamine, and trimethylamine-N-oxide), coprocessed by symbiotic gut microbiota and mammalian enzyme systems. Conversion of choline into methylamines by microbiota in strain 129S6 on a high-fat diet reduces the bioavailability of choline and mimics the effect of choline-deficient diets, causing NAFLD. These data also indicate that gut microbiota may play an active role in the development of insulin resistance.

Animals↗
PubMed1995

Predictive quantitative structure-activity relationships (QSAR) analysis of beta 3-adrenergic ligands.

A novel quantitative structure-activity relationships strategy was used to analyze seventeen beta-adrenergic ligands for which we had previously evaluated pharmacological properties in Chinese hamster ovary cells transfected with the human beta 1-, beta 2- or beta 3-adrenergic gene (Blin et al., 1993, Mol. Pharmacol., 44: 1094-1104). These ligands were classified into pharmacological activity categories in order to determine the extent to which molecular structural features may be involved in the selectivity of the interaction with the beta 3-AR, or to define molecular features and properties characteristic of a beta 3-AR high affinity ligand or of a potent beta 3-adrenergic agonist. Topological and physico-chemical molecular descriptors were obtained using a novel software combining calculations with multivariate statistical methods, such as principal component analysis and discriminant analysis. This study showed that beta 1/beta 2-antagonists beta 3-agonists could be differentiate from beta 1/beta 2/beta 3-agonists on the basis of their topological molecular descriptors weighted by partial atomic charge and lipophilicity logP values. Bulky lipophilic groups at the end of the alkylamine chain and an ethoxy function, extending the flexible portion of the molecule and modifying the electron density distribution, were requirements for selective agonism at the beta 3-site. Charge and logP weighted 2D-autocorrelation vectors were properties able to discriminate between classes of agonists in terms of their affinity, potency or intrinsic activity, thus emphasizing the part these molecular descriptors play in determining beta 3-adrenergic ligands. These results, in association with the powerful activity-prediction model evaluated in the test, provide a framework to rationalize the synthesis of new beta 3-AR specific compounds.

Adrenergic Agents↗
PubMed1999

ECL cell tumor and poorly differentiated endocrine carcinoma of the stomach: prognostic evaluation by pathological analysis.

BACKGROUND & AIMS: Gastric endocrine tumors show a wide spectrum of clinical behavior, and prognostic assessement of individual tumors is difficult. The aims of this work were to identify predictors of tumor malignancy and patient outcome and to provide a rationale for treatment guidelines. METHODS: Gastric endocrine tumors (86 enterochromaffin-like cell carcinoids and 16 poorly differentiated carcinomas) were investigated for 15 clinicopathologic variables and for expression of Ki67, P53, and BCL-2 proteins. Data were analyzed by univariate and multivariate statistics for evidence of tumor malignancy and patient survival. RESULTS: Histological grades 2 and 3, size >/=3 cm, 9 or more mitoses, or >/=300 Ki67-positive cells per 10 high-power fields identified 26 of 33 (79%) malignant (metastatic or deeply invasive) tumors, and size <1 cm and/or growth restricted to the mucosa characterized 46 of 69 (67%) tumors with benign behavior during a median follow-up of 39 months. Malignancy-predictive models were developed using angioinvasion, size, clinicopathologic type, mitotic index, and Ki67 index. The same variables, in addition to deep gastric wall invasion and histological grade, predicted patient outcome. CONCLUSIONS: Criteria for the assessment of malignancy risk and patient outcome were developed for the different tumors, providing a basis for treatment guidelines.

Analysis of Variance↗
PubMed2001

Factors affecting client response to HIV outreach efforts.

PURPOSE: This article describes 12 HIV Outreach Demonstration Projects funded by the Center for Substance Abuse Treatment in 1995, and the clients these projects served. The article also summarizes the findings of multivariate statistical analyses aimed at identifying important project and client characteristics that influenced project success in achieving two key outcomes: persuading at-risk clients to obtain HIV tests, and facilitating entry by substance-abusing clients into structured substance abuse treatment (SAT). METHODS: Hierarchical linear modeling (HLM) analysis was used to conduct the analyses. RESULTS: The findings support the hypothesis that HIV Outreach, as an integrated approach to addressing the multiple problems clients have due to substance abuse and related problems, can be an effective model for reaching clients who have not been reached through traditional means. IMPLICATIONS: By implementing a complement of comprehensive HIV Outreach interventions, many of the HIV Outreach projects were successful in addressing the various needs of their clients. However, as detailed in this article, some services and service delivery procedures, were more effective than others in achieving project objectives.

AIDS Serodiagnosis↗
PubMed2004

Ecomorphological adaptation of acorn weevils to their oviposition site.

Comparisons between closely related species in different habitats provide a window into understanding how biotic factors shape evolutionary pathways. Weevils in the genus Curculio have radiated extensively across the Palearctic, where similar ecomorphs have evolved independently on different hosts. We examined ecological and morphological data for 31 Curculio species using multivariate statistics to determine which morphological traits covary and which correlate with the host seed size. A subset of 15 taxa for which phylogenetic relationships were known were used for comparative analyses and inferring historical patterns of trait evolution. The morphological analyses suggest rostrum size increased proportionately to body size in both males and females and that both rostrum and body size correlate with host seed size but that rostrum shape does not correlate with any of the seed traits used in the analyses. Host shifts from small seeds to considerably larger seeds or vice versa have occurred several times independently and historical trait evolution indicates that these host shifts were accompanied by morphological changes in rostrum size. These patterns suggest that seed size is an important selective agent for changes in rostrum length along with body size and thus may be a key factor promoting morphological differentiation in the genus Curculio.

Adaptation, Biological↗
PubMed1993

Myocardial function in early hours after coronary artery bypass grafting: comparison of two cardioplegic methods.

The theoretical advantages of retrograde blood cardioplegia combined with anterograde blood cardioplegia and warm reperfusion before aortic unclamping during coronary surgery were evaluated in 41 patients (group 2). The early postoperative myocardial function of this group was compared with that of 55 patients (group 1) in whom cold crystalloid cardioplegia was administered. The following variables were measured and analyzed by multivariate statistical analysis: heart rate, left atrial pressure, systemic arterial pressure, cardiac index, left ventricular stroke work index, ventricular function, oxygen delivery, hemoglobin, partial oxygen pressure in mixed venous blood, arteriovenous oxygen difference, carbon dioxide production per square meter, and cardiac isoenzyme of creatine-kinase. The myocardial function improved progressively and cardiac enzymatic release was low for both groups 9 hours after admission to the intensive care unit. However, group 2 had significantly higher oxygen delivery, carbon dioxide production per square meter, cardiac index, left ventricular stroke work index, and ventricular function and significantly lower left atrial pressure and mean systemic arterial pressure than that of group 1. The best separation of group 2 from group 1 occurred at the ninth hour, with a probability of correct recognition of 92.1%.

Blood Pressure↗
PubMed1994

Variation in enamel thickness and cusp area within human maxillary molars and its bearing on scaling techniques used for studies of enamel thickness between species.

Thirty-nine unworn maxillary molars (M1 = 18, M2 = 12, M3 = 9), representing 37 individuals of a Slavic population, were sectioned through the mesial cusps in a plane perpendicular to the cervical margin of the crown. Whether the range of variation in enamel cross-sectional area between individuals corresponds to the range of variation found between teeth within a species was investigated. Total tooth crown area, as determined by planimetry, was used as a scaling factor on the basis that a biologically meaningful scaling procedure should take into account both enamel thickness and total tooth crown area, rather than the size of the dentine-enamel junction. Uni- and multivariate statistics revealed that the enamel cross-sectional area of second and third molars is absolutely and relatively larger than it is in first upper molars and that it scales close to isometry with tooth crown area. Conversely, first maxillary molars, with their relatively and absolutely thinner enamel, exhibit positive allometry between enamel and tooth crown area. These patterns were retained even when differences in overall tooth size were adjusted for. Hence, the notion that there exists a 'species-specific' amount of enamel over the tooth crown must be reconsidered, and one should refrain from pooling different tooth types for taxonomic purposes. At least two scaling factors are needed to describe human maxillary molars alone. However, this increase in enamel cross-sectional area from anterior to posterior is not unexpected if one bears in mind that posterior teeth occupy a more advantageous position relative to the chewing muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Austria↗
PubMed1997

Relationship between size of injected microspheres and ultrasound imaging of heart by PLSR.

PURPOSE: To investigate the enhancement in ultrasound signal (US) in heart, for diagnostic purposes, as a function of size and number of injected air-filled microspheres by multivariate statistical methods. METHODS: The US enhancement in left ventricle was measured after injection of 31 suspensions of air-filled albumin microspheres divided on and injected in six dogs. The relationship between the size of microspheres between 1-38 microns and the US enhancement was explored by Pearson's product moment correlation analysis, ordinary least-squares regression, principal component regression (PCR) and partial least-squares regression (PLS). RESULTS: Relative advanced algorithms such as PCR and PLS were required to achieve accurate in vivo/in vitro correlation. The most effective microsphere sizes contributing to US enhancement in left ventricle in dogs were estimated to be in the 7-15 microns range. CONCLUSIONS: In general, the effective in vivo sizes are dependent on the type of formulation due to the surprisingly large active in vivo sizes found for the tested concept. PCR and PLS are suitable methods for in vivo/in vitro correlation, especially for covariated and noisy data.

Albumins↗
PubMedDate not supplied

[The effect of lesions of different parts of the optic thalamus on the nature of the bioelectrical activity of the human brain].

The EEG recordings of 41 patients with thalamic arteriovenous malformations (AVM) were studied by means of multivariate statistical analysis. In 16 patients the AVM were located in pulvinar, in 17 patients in the ventrolateral, in 4 patients in the medial, and in the remaining 4 patients in the anterior thalamic regions. Pathological EEG signs were visually classified and subjected to analysis of variance. The EEG signs were separated caused by the lesion localization. It was shown that the lesions in the posterior thalamus resulted in the alpha-rhythm suppression up to its total elimination. It was substituted for the bilateral local pathological activity in the posterior areas of the hemispheres. The diffuse beta-activity was observed. The ventrolateral and medial thalamic lesions led to the alpha-rhythm disorganization and its exaltation. The local slow waves were revealed in the sensorimotor cortical areas. The diffuse slow activity was observed as well as the signs of diencephalic irritation in the form of bilaterally synchronous bursts of activity in the alpha-theta range.

Electroencephalography↗
PubMed1999

Neurological complications after cardiopulmonary bypass: An update.

INTRODUCTION: Neurological complications are, at the present time, considered among the most important causes of morbidity and mortality after heart surgery. We evaluated their importance and risk factors. PATIENTS AND METHODS: We retrospectively reviewed 2, 528 consecutive patients who underwent cardiopulmonary bypass in a single center. In each one, we attended to previous vascular risk factors, such as surgical and postoperative events. We considered four categories of neurologic outcome: (1) persistent neurological focal deficits, (2) stupor or coma, (3) temporary neurological focal deficits, and (4) seizures. We carried out univariant and multivariant statistical analysis, looking for predictors of adverse neurologic events. RESULTS: Neurological complications occurred in 76 patients (3%); 36 of them (47%) had persistent neurological focal deficits, 18 (24%) stupor or coma, 18 (24%) temporary neurological focal deficits, and 27 (36%) seizures. Twenty-two patients with cerebral adverse outcomes died (29%), the overall mortality among the 2,528 cases being 5%. Predictors of risk were aortic aneurysm and aortic valve surgery, advanced age, female sex, and the use of intra-aortic balloon pump. A longer hospitalization time was noticed among patients with neurological side effects. DISCUSSION: Neurological complications are common and serious after heart surgery, as we have noticed with this series, the largest up to now, according to our review of the literature. They increase perioperative mortality and hospitalization time. Neurological morbidity and risk factors in our study are similar to those previously published.

Cardiopulmonary Bypass↗
PubMed1998

Relationship among risk factors of atherosclerosis, leukocyte count, and soluble intercellular adhesion molecule-1.

We investigated the effects of risk factors of atherosclerosis on soluble intercellular adhesion molecule-1 (sICAM-1) concentration and leukocyte count by using multivariate statistical analysis. The subjects were 90 people who were hospitalized for a complete check-up examination. Eight risk factors were selected as candidates for predictor variables: age, body mass index (BMI), uric acid, glycohemoglobin A1c, number of cigarettes smoked daily, total cholesterol, triglyceride, and high density lipoprotein (HDL)-cholesterol. The predictor variables were selected using a stepwise method, [criterion variable - predictor variable (standardized regression coefficient)]; sICAM1 - age (0.1859), number of cigarettes (0.2558), triglyceride (0.2447); leukocytes - number of cigarettes (0.2827), triglyceride (0.2526), HDL-cholesterol (-0.2800); stab leukocytes - number of cigarettes (0.2460); segmented leukocytes - glycohemoglobin A1c (0.1495), number of cigarettes (0.2716), HDL-cholesterol (-0.3254); lymphocytes - BMI (0.2639), number of cigarettes (0.1495), triglyceride (0.3520); monocytes - glycohemoglobin A1c (0.2617). These findings indicated that the risk factors of atherosclerosis may influence sICAM1 concentration and leukocyte count.

Adult↗
PubMed2000

Brodmann's areas 17 and 18 brought into stereotaxic space-where and how variable?

Studies on structural-functional associations in the visual system require precise information on the location and variability of Brodmann's areas 17 and 18. Usually, these studies are based on the Talairach atlas, which does not rely on cytoarchitectonic observations, but on comparisons of macroscopic features in the Talairach brain and Brodmann's drawing. In addition, in this atlas are found only the approximate positions of cytoarchitectonic areas and not the exact borders. We have cytoarchitectonically mapped both areas in 10 human brains and marked their borders in corresponding computerized images. Borders were defined on the basis of quantitative cytoarchitecture and multivariate statistics. In addition to borders of areas 17 and 18, subparcellations within both areas were found. The cytoarchitectonically defined areas were 3-D reconstructed and transferred into the stereotaxic space of the standard reference brain. Surface rendering of the brains revealed high individual variability in size and shape of the areas and in the relationship to the free surface and sulci. Ranges and centers of gravity of both areas were calculated in Talairach coordinates. The positions of areas 17 and 18 in the stereotaxic space differed between the hemispheres. Both areas reached significantly more caudal and medial positions on the left than on the right. Probability maps were created in which the degree of overlap in each stereotaxic position was quantified. These maps of areas 17 and 18 are the first of their kind and contain precise stereotaxic information on both interhemispheric and interindividual differences.

Adult↗
PubMed1993

Stimulation-induced damage in rabbit fast-twitch skeletal muscles: a quantitative morphological study of the influence of pattern and frequency.

The aim of this study was to determine whether muscle fibre degeneration brought about by chronic low-frequency electrical stimulation was related to the pattern and frequency of stimulation. Rabbit fast-twitch muscles, tibialis anterior and extensor digitorum longus, were stimulated for 9 days with pulse trains ranging in frequency from 1.25 Hz to 10 Hz. Histological data from these muscles were analysed with multivariate statistical techniques. At the lower stimulation frequencies there was a significantly lower incidence of degenerating muscle fibres. Fibres that reacted positively with an antineonatal antibody were most numerous in the sections that revealed the most degeneration. The dependence on frequency was generally similar for the two muscles, but the extensor digitorum longus muscles showed more degeneration than the tibialis anterior at every frequency. Muscles subjected to 10 Hz intermittent stimulation showed significantly less degeneration than muscles stimulated with 5 Hz continuously, although the aggregate number of impulses delivered was the same. The incidence of degeneration in the extensor digitorum longus muscles stimulated at 1.25 Hz was indistinguishable from that in control, unstimulated muscles; for the tibialis anterior muscles, this was also true for stimulation at 2.5 Hz. We conclude that damage is not an inevitable consequence of electrical stimulation. The influence of pattern and frequency on damage should be taken into account when devising neuromuscular stimulation regimes for clinical use.

Animals↗