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At least 19 recordsLinked to original sources
PubMed1975

Improvement of scintigram reliability by isocount scanning and multilevel analysis.

Given the target source conditions and the detector parameters, the isocount scanning uses optimally the available observation time by maintaining the statistical reliability of each measurement in the composition of a scintigram and by devoting all the observation time to the region of interest through logic circuits which allows quick skipping of the background region. The multilevel analysis is an effective enlargement of the dynamic range of the displayer screen density characteristics that emphasizes small uptake ratios in any density level. It also makes the features extraction very easy by producing an animated sequence of pictures of the observed organ on the screen. The detectability of small uptake ratios significantly improved, specially in regions of low counting rate where the fluctuation of data severely degrades the picture quality in the conventional constant speed scanning method.

Brain Neoplasms↗
PubMed1992

Social psychological contributions to the decade of the brain. Doctrine of multilevel analysis.

The 1990s were declared by Congress to be the "decade of the brain." This declaration is important to all psychologists, not only neuroscientists, because with this declaration come expectations of the cognitive and behavioral sciences generally and because the brain does not exist in isolation but rather is a fundamental component of developing and aging individuals who themselves are mere actors in the larger theater of life. This article examines the importance of a multilevel, integrative approach to the study of mental and behavioral phenomena in the decade of the brain, reviews how this approach highlights the synergistic relationship between theoretical and clinically relevant research, and illustrates how this approach can foster the transition from microtheories to general psychological theories.

Behavior↗
PubMed1991

Nutritional support in HIV infection: a multilevel analysis.

Infection with the human immunodeficiency virus (HIV) and the development of the acquired immunodeficiency syndrome (AIDS) is a long-term process in many individuals. The progression of HIV disease is beginning to demonstrate many commonalities with other chronic diseases. Although research has not yet shown clear-out evidence that diet can make a difference in the course of disease in HIV-infected clients, nutrition should be viewed as an important component of holistic care for HIV-infected clients because: 1) wasting and symptoms of malnutrition are common problems associated with these clients; and 2) nutrition has proven to be a beneficial component of care in other chronic conditions. This paper uses the model developed by Winett, King and Altman (1989) to review nutritional support in HIV infection from a multilevel perspective ranging from personal psychology to institutional/societal controls. The author concludes that there is a potential benefit from integrating nutritional assessment, diagnosis and education into the holistic care of HIV-infected clients at the personal, interpersonal, organizational and societal levels.

Comprehensive Health Care↗
PubMed1977

[Isocount scanning in brain tumors-a quantitative investigation of the tracer activity (author's transl)].

In the previous reports, the theoretical background [corrected] and technical details of the Isocount scanning were described. Based on clinical experiences of various brain diseases, the newly developed scanning method was confirmed to be more useful than the conventional scintiscanning. Besides the new scanning method, a new display system was also developed for the sake of more precise analysis of the Isocount scanned data. This display method is called MULTILEVEL ANALYSIS or MULTILEVEL SLICING. In the present investigation, this method was applied to fortysix cases of brain tumors, including forty cases of supratentorial tumors and six cases of infratentorial tumors, positive rates being 95% and 67% respectively. Furthermore, as a measure of the quantitative investigation of the radioactive tracer uptake of the target area, the maximum uptake rate of the target area (RTmax.=Tmax./NTmean), and the deviation index (DI=DT/DNT) were introduced; Tmax., NTmean, DT and DNT are respectively defined as a maximum uptake of the target area, a mean uptake of the non-target area, a deviation rate of the target area and a deviation rate of the non-target area. They can be obtained from analysing the television figures of MULTILEVEL ANALYSIS. By this method, thirty-four cases of supratentorial tumors were studied. In cases of glioma (12 scans), meningioma (9 scans), and metastatic tumor (7 scans), the mean values of RTmax. were 1.26, 1.37, and 1.24 and the mean values of DI were 0.81, 0.68 and 0.60 respectively. In gliomas, the RTmax. and the DI were correlated with the degree of malignancy of the tumors. This quantitative analysis could be considered to be useful to foresee the nature of the brain tumor from the scintiscanning findings.

Adolescent↗
PubMed2026

Systematic Identification of Therapeutic Targets and Repurposed Drugs for Stroke: From Genome Causal Analysis to Multilevel Validation.

BACKGROUND: Stroke is a severe cerebrovascular disease characterized by narrow time windows and complications. This study aimed to identify novel drug targets and repurposed drugs for stroke. METHODS: This study used expression quantitative trait loci data from druggable genes in brain and blood as instrumental variables. Mendelian randomization, colocalization, and phenome-wide Mendelian randomization were applied to evaluate causal relationships and potential side effects, with stroke and ischemic stroke as primary outcomes. Preclinical validation used oxygen-glucose deprivation/reperfusion and middle cerebral artery occlusion/reperfusion models. Pharmacological and behavioral assessments evaluated the therapeutic potential of candidate targets and drugs. Additionally, proteomic sequencing was performed following GGCX (γ-glutamyl carboxylase) overexpression to explore its biological functions. RESULTS: Elevated GGCX expression in brain and blood was potentially causally associated with reduced risk of stroke and ischemic stroke, supported by colocalization evidence, although potential cardiovascular risks could not be excluded. Drug repositioning identified ifenprodil as a candidate agent that reduced infarction volume, improved motor and cognitive functions, and reversed GGCX downregulation in mice. Ifenprodil treatment and GGCX overexpression alleviated oxygen-glucose deprivation/reperfusion-induced injury and upregulated GGCX expression. Mechanistically, GGCX conferred neuroprotection by regulating protein homeostasis, suppressing inflammation, promoting metabolic recovery, and modulating nuclear transcriptional regulation. CONCLUSIONS: This study established a potential causal link between GGCX and stroke risk, particularly ischemic stroke. GGCX represents a promising therapeutic target for ischemic stroke. Targeted GGCX expression upregulation and drug repurposing, particularly ifenprodil, may offer novel therapeutic avenues. Further validation is warranted to assess clinical efficacy and safety.

Animals↗
PubMed2024

Geospatial Analysis of Multilevel Socioenvironmental Factors Impacting the Campylobacter Burden among Infants in Rural Eastern Ethiopia: A One Health Perspective.

Increasing attention has focused on health outcomes of Campylobacter infections among children younger than 5 years in low-resource settings. Recent evidence suggests that colonization by Campylobacter species contributes to environmental enteric dysfunction, malnutrition, and growth faltering in young children. Campylobacter species are zoonotic, and factors from humans, animals, and the environment are involved in transmission. Few studies have assessed geospatial effects of environmental factors along with human and animal factors on Campylobacter infections. Here, we leveraged Campylobacter Genomics and Environmental Enteric Dysfunction project data to model multiple socioenvironmental factors on Campylobacter burden among infants in eastern Ethiopia. Stool samples from 106 infants were collected monthly from birth through the first year of life (December 2020-June 2022). Genus-specific TaqMan real-time polymerase chain reaction was performed to detect and quantify Campylobacter spp. and calculate cumulative Campylobacter burden for each child as the outcome variable. Thirteen regional environmental covariates describing topography, climate, vegetation, soil, and human population density were combined with household demographics, livelihoods/wealth, livestock ownership, and child-animal interactions as explanatory variables. We dichotomized continuous outcome and explanatory variables and built logistic regression models for the first and second halves of the infant's first year of life. Infants being female, living in households with cattle, reported to have physical contact with animals, or reported to have mouthed soil or animal feces had increased odds of higher cumulative Campylobacter burden. Future interventions should focus on infant-specific transmission pathways and create adequate separation of domestic animals from humans to prevent potential fecal exposures.

Humans↗
PubMed1975

[Diagnostic value of isocount scanning in cerebrovascular diseases (author's transl)].

In the previous report the theoretical background and technical details of the isocount scanning were described. Based on clinical experiences of various brain diseases, the newly developed scanning method was confirmed to be more useful than the conventional scintiscanning. Besides the new scanning method, a new display system was also developed for the sake of more precise analysis of the isocount scanned data. This display method is called multilevel analysis or multilevel slicing of the scanned data. In the present investigation, this method was applied to thirty-two cases of cerebrovascular diseases, including seven cases of cerebral arterio-venous malformation, four cases of hypertensive intracerebral hemorrhage and twenty-one cases of cerebral infarction, positive rates being 86%, 100% and 90% respectively. In case of arterio-venous malformation, minimum size detected by the isocount method was 2 cm in diameter. To twenty one cases of the cerebral infarction, total thirty two scanning examinations were performed, including postictal follow up studies. It is often said that it is two or three weeks after the ictus when the infarcted cerebral lesion is most clearly detectable by the scintigraphic procedures, presumably due to focal neovascularizations which may occur in the lesion most prominently at this postictal stage. Contradicted to the current concept, our experiences show that abnormal dot accumulations are recognized in the scintigrams even at the earlier stage, thus among five cases of cerebral infarction scanned within a week after the ictus positive figures were obtained in four cases, two of which were examined within two days after the ictus. Focal breakdown of blood brain barrier at the acute stage is considered to be responsible for the early positivity in cerebral infarctions. In eight cases among twenty one cerebral infarctions angiographies failed to demonstrate the vessel occluded. The isocount scanning method, however, succeeded in getting positive results in seven of the eight cases. It will be emphasized that the isocount scanning is a preferable diagnostic procedure in the cerebrovascular diseases, especially when the angiography is hesitated to be performed because of the patient severely affected.

Adolescent↗
PubMed1991

Multilevel modelling of longitudinal cephalometric data explained for orthodontists.

Multilevel modelling of longitudinal data is an important new statistical technique. In this article some of the basic concepts and ideas of multilevel modelling are explained. The model is introduced by showing how individual and average growth can be modelled. The intercept, linear and quadratic coefficient, between and within variance, fixed and random part, and other concepts of multilevel modelling are explained. Attention is also given to the reading of statistical tables of the results of multilevel analysis. In the conclusion some of the advantages of multilevel modelling of cephalometric data are mentioned.

Aging↗
PubMedDate not supplied

Use of tissue culture models to study neuronal regulatory trophic and toxic factors in the aged brain.

Dementia is believed to result from the loss of selective neurons within the brain, but approaches for systematic study of that degenerative process are hampered by the complexity of the neuronal milieu. Tissue culture models provide a means to reduce dramatically the variables inherent in the study of neuronal plasticity. Three levels of complexity can be described: cellular and molecular diversity; primary and secondary interconnections; and finally, the dynamics influenced by age. The following review discusses the advantages and disadvantages of tissue culture models for the detailed study of neuronal trophic and toxic factors. Our selection of factors is broadened to include ions, intermediate metabolites, antioxidants, steroids, neuropeptides, gangliosides, metals, neurotransmitters, brain extracts, and protein molecules. Most of these factors have been shown to be altered in the aged brain, to have a significant effect on cultured neurons, or both. This multilevel analysis provides the reader with an overview of the events regulating neuronal survival, differentiation and death. An understanding of these basic questions is necessary to sequence the molecular events resulting in neuronal death.

Aging↗
PubMed1991

Vertical facial growth: a longitudinal study from 7 to 14 years of age.

Multilevel analysis is used to describe the changes in vertical facial dimensions and their relationships in Dutch girls between 7 and 14 years of age. For the anterior face height (nasion-gnathion) and the posterior face height (sella-gonion) a fourth degree polynomial was fitted. The mandibular plane angle (sella nasion-gonion gnathion) could be described with a second degree polynomial. Low correlations were found between the growth parameters (intercept and age coefficient) of the anterior and posterior face height, which points to independent growth and development of the anterior and posterior face height. The individual length and growth velocity (at age 10.8) of the anterior face height and the mandibular plane angle showed substantial correlations. It was concluded that changes during growth with regard to the mandibular plane angle are more strongly related to the anterior than to the posterior face height.

Adolescent↗
PubMed1990

[Pathogenesis of congenital heart defects: fiction and truth].

This is a review based on a description of a standardized method (microdissection + SEM) for study of human and animal cardiac development. Two examples of the analytical approach are given. In the first one, concerning the establishment of contact between the aorta and the left ventricle, the previous assumptions for "vectorial bulbus rotation" are disproved by more precise observations of normal cardiac development. Aorta is not transferred into the left ventricle but is connected to it by means of a "conduit" (aortic vestibulum) delimited by the fusion of the conotruncus ridges. For the second example the multilevel-analysis of pathogenesis of conotruncus septum defects in Keeshond dogs was selected. At the organ level, hypoplasia of the right ventricle was diagnosed, accompanied by hypoplasia of conus cushions. Tissue-level analysis indicated that the major cause of these hypoplasias is a decreased relative volume of the myocardium. Further study at the cell level showed that the number of mesenchymal cells in certain parts of conotruncus cushions is also diminished. Combining these observations with what is known about the architecture of cell proliferation in the embryonic heart, allows to formulate a hypothesis on a selective lesion of the right proliferation center, as one of the main causes of the observed anomalies. Further progress towards the subcellular and molecular level will help to complete the pathway from a gene defect toward an organ defect.

Animals↗
PubMed1989

Integrating theory and research on the institutional determinants of fertility.

This article links recent conceptual theories regarding the determinants of fertility with research designs appropriate for testing those theories. The most important causal factors in these theories--typically social or cultural institutions, occasionally emergent properties of the collective behavior of individuals--are properly conceptualized at the macro level. Research designs must therefore feature variation at this level and are at a minimum comparative. Noncomparative micro-level research designs will be misspecified from the standpoint of theory. A case is also made for continuing to incorporate the observation of individual-level behavior into any comprehensive research design. A focus on macro determinants of fertility does not imply that fertility outcomes are determined at the institutional level. Instead, there remains some process whereby systemic properties are translated into individual behaviors. Recommendations for comparative community-level studies are discussed. The multilevel analysis framework is reviewed as a paradigm for the conceptual features of cross-contextual analysis.

Data Interpretation, Statistical↗
PubMed1977

[Isocount scanning in the diagnosis of the brain abscess (author's transl)].

The purpose of this study is to investigate salient diagnostic features of the brain abscess in RI brain scanning. In 27 patients with brain abscess, 37 scannings were performed in the various stages of their clinical courses. The results were positive in all cases. Among 27 cases, ten cases were investigated by means of the ISOCOUNT SCANNING SYSTEM, the technical detail of which was reported previously. It was proved that the isocount scanning method combined with the multilevel analysis was more sensitive diagnostic aid than the conventional RI scintigraphy. Using the newly developed method, it was not difficult to diagnose the brain abscess in its early stage, even in the stage of presuppurative cerebritis. Doughnut sign was seemed to be more frequently visualized by this method. Surgical indication of the brain abscess was discussed from nucleomedical view point, and it was emphasized that so-called doughnut sign in brain scanning would indicate the appropriate stage of the brain abscess to be operated on.

Adolescent↗
PubMed2026

Adherence and effectiveness of multicomponent exercise fall prevention programmes across delivery formats in community-dwelling older adults: a systematic review and multilevel meta-analysis.

BACKGROUND: Multicomponent exercise is widely implemented for fall prevention in older adults, but the role of exercise adherence and delivery format in determining intervention effectiveness remains inadequately understood, particularly in analyses that account for within-study outcome dependence. METHODS: We searched five databases to 23 November 2025 for RCTs of multicomponent exercise in adults aged ≥60 years. Fall outcomes were synthesised using three-level random-effects meta-analysis and meta-regression, with adherence evaluated as continuous/categorical factors and as moderator alongside delivery format, accounting for within-study effect-size dependence. RESULTS: Forty-one publications were included, comprising 36 distinct cohorts and involving 20,202 participants. Multicomponent exercise programmes significantly reduced fall incidence (IRR = 0.776, 95% CI 0.641-0.939), risk of experiencing at least one fall (RR = 0.914, 95% CI 0.858-0.974), and fall-related injury incidence (IRR = 0.754, 95% CI 0.663-0.858). Programmes achieving adherence ≥75% were independently associated with greater reductions in fall incidence (IRR = 0.501, 95% CI 0.336-0.747) and fall risk (RR = 0.821, 95% CI 0.697-0.967). Mean adherence was highest in combined individual and group delivery, lower in single-format programmes, though including a group component may enhance adherence. CONCLUSIONS: Multicomponent exercise fall prevention programmes are effective for fall prevention in community-dwelling older adults, whereas evidence for their protective effects on fall-related injury outcomes remains limited. Adherence is an important factor influencing programme implementation and intervention effectiveness.

Aged↗
PubMed2025

Association Between Ratio of Triglycerides to HDL-C and Cognitive Impairment: A Longitudinal Population-Based Analysis and Mendelian Randomization Study.

OBJECTIVES: This study aimed to explore the longitudinal association between the triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio and cognitive impairment in older adults and further assess potential causality using Mendelian randomization (MR). DESIGN: Longitudinal population-based analysis combined with two-sample MR. Data from Waves 6-8 (2015-2019) of the Survey of Health, Ageing, and Retirement in Europe (SHARE) were analyzed using hierarchical regression models and mixed linear effects models. MR utilized genome-wide association studies (GWAS) summary data. PARTICIPANTS: 11,444 adults aged &#x2265;60 years from SHARE Wave 6, with longitudinal follow-up in Waves 7 (N = 2,775) and 8 (N = 5,469). MEASUREMENTS: TG/HDL-C ratio, cognitive function (orientation, immediate/delayed recall, verbal fluency, numeracy), and cognitive impairment (defined as scores >1.5 SD below age-group mean). Covariates included socio-demographics, health behaviors, comorbidities, and national-level factors. MR employed genetic variants associated with TG/HDL-C as instrumental variables. RESULTS: Higher TG/HDL-C ratios were negatively associated with total cognitive scores (&#x3b2; = -0.115, &#x3c7;&#xb2; = 15.44, df = 1, p < 0.001), immediate recall (&#x3b2; = -0.029, &#x3c7;&#xb2; = 12.34, df = 1, p < 0.001), delayed recall (&#x3b2; = -0.028, &#x3c7;&#xb2; = 7.33, df = 1, p < 0.001), verbal fluency (&#x3b2; = -0.038, &#x3c7;&#xb2; = 11.53, df = 1, p < 0.001), and numeracy (&#x3b2; = -0.019, &#x3c7;&#xb2; = 4.55, df = 1, p < 0.05) in fully adjusted models. Longitudinal analysis revealed increased cognitive impairment risk in the highest TG/HDL-C quartile (OR=1.43, 95% CI:1.01-2.03, &#x3c7;&#xb2; = 9.24, df = 1) over 4 years. MR supported a causal link between elevated TG/HDL-C and cognitive decline. CONCLUSIONS: Elevated TG/HDL-C ratios are longitudinally associated with cognitive decline in older adults. Managing lipid metabolism may mitigate cognitive impairment, highlighting the importance of TG/HDL-C as a modifiable risk factor in aging populations.

Humans↗
PubMed1986

An automated technique for analysis of current transitions in multilevel single-channel recordings.

Detailed kinetic studies of ion channel gating are best carried out using the patch-clamp technique which permits the measurement of the ionic current through individual channels. Typical patch-clamp recordings show the current signal, in the form of a sequence of rectangular pulses (analogous to a random telegraph signal), riding on slow baseline drift, partially obscured by high-frequency noise and distorted by filtering. In order to analyze such recordings, we have developed a set of interactive Pascal programs based on a feature-detection algorithm capable of identifying current transitions in multiple-channel recordings in the presence of substantial levels of noise and drift. Software operation is largely automated but includes provisions for examination and correction of the output. The software was optimized and systematically evaluated using simulated data with variable amounts of noise and drift. Results indicate that satisfactory performance is obtained for signal-to-noise ratio as low as four even with uncommonly large baseline drift. Steady-state processing speeds varied from 1,000 to 4,000 samples per second depending on data complexity.

Automation↗
PubMed1987

Prevention and ecology: teen-age pregnancy, child sexual abuse, and organized youth sports.

A multilevel ecological analysis of issues that impact on children and families is advocated as the best theoretical framework for conceptualizing preventive interventions. Teen-age pregnancy and child sexual abuse are discussed as targets of preventive intervention: the former being an issue about which we have much information that has not been adequately used, whereas the latter is one about which we have too little information to be mounting the sweeping prevention programs that are rapidly coming into existence. Organized youth sports is then discussed as a neglected societal vehicle for prevention.

Adolescent↗