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PubMed1994

Alcohol dehydrogenase of class IV (sigma sigma-ADH) from human stomach. cDNA sequence and structure/function relationships.

Human stomach mucosa contains a characteristic alcohol dehydrogenase (ADH) enzyme, sigma sigma-ADH. Its cDNA has been cloned from a human stomach library and sequenced. The deduced amino acid sequence shows 59-70% identities with the other human ADH classes, demonstrating that the stomach enzyme represents a distinct structure, constituting class IV, coded by a separate gene, ADH7. The amino acid identity with the rat stomach class IV ADH is 88%, which is intermediate between constant and variable dehydrogenases. This value reflects higher conservation than for the classical liver enzymes of class I, compatible with a separate functional significance of the class IV enzyme. Its enzymic features can be correlated with its structural characteristics. The residues lining the substrate-binding cleft are bulky and hydrophobic, similar to those of the class I enzyme; this explains the similar specificity of both classes, compatible with the origin of class IV from class I. Position 47 has Arg, in contrast to Gly in the rat class IV enzyme, but this Arg is still associated with an extremely high activity (kcat = 1510 min-1) and weak coenzyme binding (KiaNAD+ = 1.6 mM). Thus, the strong interaction with coenzyme imposed by Arg47 in class I is probably compensated for in class IV by changes that may negatively affect coenzyme binding: Glu230, His271, Asn260, Asn261, Asn363. The still higher activity and weaker coenzyme binding of rat class IV (kcat = 2600 min-1, KiaNAD = 4 mM) can be correlated to the exchanges to Gly47, Gln230 and Tyr363. An important change at position 294, with Val in human and Ala in rat class IV, is probably responsible for the dramatic difference in Km values for ethanol between human (37 mM) and rat (2.4 M) class IV enzymes.

Alcohol Dehydrogenase↗
PubMed1993

Immunohistochemistry of neuronal inclusions in the cerebral cortex and brain-stem in Lewy body disease.

Three cases of Lewy body disease were investigated in order to compare the morphological and immunohistochemical characteristics of the neuronal inclusions in the cerebral cortex (CC) and brain-stem (BS). Ultrastructurally, the CC contained intermediate-sized filaments with variable amounts of granular material and other organelles, whereas the BS consisted of an electron-dense core and an outer area with radially oriented filaments. The cerebral cortex was immuno-reactive with antibodies against tyrosine hydroxylase (TH) and tau protein, and differed from BS. In addition, although the CC were antigenically similar to BS in their neurofilament (70, 160 and 200 kDa) and ubiquitin contents, the localization of neurofilament immunoreactivity differed between them, being confined positively to the core of CC, but to the periphery of the BS. Although Lewy bodies (LB) in idiopathic Parkinson's disease are morphologically similar to BS, they have been reported to differ in their immunoreactivity with antibodies against tau. It has been reported that CC differ from LB with regard to immunoreactivity with antibodies against TH and tropomyosin. It is inferred that these inclusions (CC, BS and LB) differ in morphogenesis.

Aged↗
PubMed1987

Effects of seven low dose combined oral contraceptives on high density lipoprotein subfractions.

The effects on lipid metabolism of seven combined oral contraceptives were investigated, particularly the effects on high density lipoprotein (HDL) subfractions, which were separated by density gradient ultracentrifugation. There were no differences between the preparations in the effects on the LDL fraction, the so-called atherogenic particle, but there were marked differences in the effects on the anti-atherogenic HDL fraction, of which the effects on HDL-2 were most pronounced. After treatment with monophasic cyproterone acetate and biphasic desogestrel, the cholesterol and phospholipid contents of the HDL-2 fraction were significantly higher than those found after treatment with the other preparations. The lowest values were found after treatment with monophasic levonorgestrel, whereas monophasic desogestrel, triphasic levonorgestrel, monophasic norethisterone and triphasic gestoden induced intermediate values for these variables. The levels of HDL-2 reflect the intrinsic androgenicity of the various progestogens used in the preparations.

Adolescent↗
PubMed1999

Intraspecific diversity of the 23S rRNA gene and the spacer region downstream in Escherichia coli.

The molecular microevolution of the 23S rRNA gene (rrl) plus the spacer downstream has been studied by sequencing of different operons from some representative strains of the Escherichia coli ECOR collection. The rrl gene was fully sequenced in six strains showing a total of 67 polymorphic sites, a level of variation per nucleotide similar to that found for the 16S rRNA gene (rrs) in a previous study. The size of the gene was highly conserved (2902 to 2905 nucleotides). Most polymorphic sites were clustered in five secondary-structure helices. Those regions in a large number of operons were sequenced, and several variations were found. Sequences of the same helix from two different strains were often widely divergent, and no intermediate forms existed. Intercistronic variability was detected, although it seemed to be lower than for the rrs gene. The presence of two characteristic sequences was determined by PCR analysis throughout all of the strains of the ECOR collection, and some correlations with the multilocus enzyme electrophoresis clusters were detected. The mode of variation of the rrl gene seems to be quite similar to that of the rrs gene. Homogenization of the gene families and transfer of sequences from different clonal lines could explain this pattern of variation detected; perhaps these factors are more relevant to evolution than single mutation. The spacer region between the 23S and 5S rRNA genes exhibited a highly polymorphic region, particularly at the 3' end.

Bacterial Typing Techniques↗
PubMedDate not supplied

Pancreatic neoplasms: MR imaging and pathologic correlation.

Magnetic resonance (MR) imaging can aid in the detection and characterization of many pancreatic neoplasms. The MR imaging appearances of common pancreatic neoplasms such as ductal adenocarcinoma are well-known. However, MR imaging features of more unusual pancreatic neoplasms are not well understood. Such tumors include mucin-hyper-secreting carcinoma, serous microcystic neoplasm, mucinous macrocystic neoplasm, solid and papillary epithelial neoplasm, multiple cysts associated with von Hippel-Lindau disease, acinar cell carcinoma, pancreaticoblastoma, and endocrine neoplasms (eg, nonfunctioning islet cell tumors, insulinoma, and gastrinoma). In general, pancreatic neoplasms demonstrate high signal intensity on T2-weighted images; the signal intensity on T1-weighted images is more variable but is often intermediate or low. Gadolinium enhancement is often helpful in further characterizing pancreatic neoplasms. The gross and histologic features of pancreatic neoplasms are also not well-known. Correlation with the underlying pathologic features enhances understanding of the MR imaging characteristics of both common and unusual pancreatic neoplasms.

Adenocarcinoma, Mucinous↗
PubMed1994

Bovine pulmonary blastomas: histomorphologic description and immunohistochemistry.

Three adult female dairy cattle with pulmonary blastomas were evaluated. The gross lesions at postmortem were described as multiple white circumscribed masses throughout the lungs, with pleural involvement in one cow and lymph node metastasis in the other two cows. Histologically, the tumors contained a dual population of mesenchymal and epithelial neoplastic cells. Epithelial cells formed nests, tubules, and formations resembling bronchioles of normal lung. Mesenchymal cells were spindle shaped with oval nuclei and fibrillar eosinophilic cytoplasm, were large rounded cells with multiple round nuclei and granular eosinophilic cytoplasm, or appeared blast-like, with large hyperchromatic nuclei and amphophilic cytoplasm. The tumors varied greatly in appearance from one field to another within the same tumor. Epithelial cells stained positively with anticytokeratin antibodies. Some spindle-shaped mesenchymal cells exhibited smooth muscle cell differentiation with positive staining with anti-vimentin, anti-muscle-specific actin, and anti-smooth muscle actin antibodies, whereas other rounded mesenchymal cells expressed striated muscle cell differentiation with multiple nuclei and positivity to anti-neuron-specific enolase and anti-muscle-specific actin antibodies. The variable expression of the intermediate filaments and cytoplasmic enzymes indicates multiple pathways of differentiation in the pulmonary blastomas.

Animals↗
PubMed1988

Effectiveness of four school health education projects upon substance use, self-esteem, and adolescent stress.

The purpose of this investigation was to evaluate the effectiveness of school health education projects on substance use, self-esteem, and stress. The subjects were 161 adolescents in fifth through eighth grades in four school health education projects funded through the Ohio Department of Health. Data collection included pretest/posttest questionnaires on self-report use of tobacco products, alcohol, marijuana, and other drugs. In addition, the Hare Self-Esteem and the Adolescent Stress Symptomology Scales were utilized. There was a six-week interval between pretest and posttest administration. MANCOVA, with age as a covariate, was used to compare pretest/posttest scores for self-esteem and stress symptomology. Furthermore, interviews were conducted with project staff about the educational methodology of their intervention. The results revealed that the predominate educational method used by the projects was lecture/discussion. There were no significant differences between pretest/posttest questionnaires for frequency of substance use, self-esteem, or stress symptomology. Effective school health education programs need sufficient quantity and quality in order to have an impact on health behaviors and the intermediate health-enhancing variable of self-esteem.

Adolescent↗
PubMed2005

Characterization of cytoskeletal and junctional proteins expressed by cells cultured from human arachnoid granulation tissue.

BACKGROUND: The arachnoid granulations (AGs) are projections of the arachnoid membrane into the dural venous sinuses. They function, along with the extracranial lymphatics, to circulate the cerebrospinal fluid (CSF) to the systemic venous circulation. Disruption of normal CSF dynamics may result in increased intracranial pressures causing many problems including headaches and visual loss, as in idiopathic intracranial hypertension and hydrocephalus. To study the role of AGs in CSF egress, we have grown cells from human AG tissue in vitro and have characterized their expression of those cytoskeletal and junctional proteins that may function in the regulation of CSF outflow. METHODS: Human AG tissue was obtained at autopsy, and explanted to cell culture dishes coated with fibronectin. Typically, cells migrated from the explanted tissue after 7-10 days in vitro. Second or third passage cells were seeded onto fibronectin-coated coverslips at confluent densities and grown to confluency for 7-10 days. Arachnoidal cells were tested using immunocytochemical methods for the expression of several common cytoskeletal and junctional proteins. Second and third passage cultures were also labeled with the common endothelial markers CD-31 or VE-cadherin (CD144) and their expression was quantified using flow cytometry analysis. RESULTS: Confluent cultures of arachnoidal cells expressed the intermediate filament protein vimentin. Cytokeratin intermediate filaments were expressed variably in a subpopulation of cells. The cultures also expressed the junctional proteins connexin43, desmoplakin 1 and 2, E-cadherin, and zonula occludens-1. Flow cytometry analysis indicated that second and third passage cultures failed to express the endothelial cell markers CD31 or VE-cadherin in significant quantities, thereby showing that these cultures did not consist of endothelial cells from the venous sinus wall. CONCLUSION: To our knowledge, this is the first report of the in vitro culture of arachnoidal cells grown from human AG tissue. We demonstrated that these cells in vitro continue to express some of the cytoskeletal and junctional proteins characterized previously in human AG tissue, such as proteins involved in the formation of gap junctions, desmosomes, epithelial specific adherens junctions, as well as tight junctions. These junctional proteins in particular may be important in allowing these arachnoidal cells to regulate CSF outflow.

Journal Article↗
PubMed1995

Type XI and II collagen-induced arthritis in rats: characterization of inbred strains of rats for arthritis-susceptibility and immune-responsiveness to type XI and II collagen.

To determine the relationship between susceptibility to bovine type XI and II (BXI and BII) collagen-induced arthritis, we immunized 14 inbred and one outbred strains of rats with BXI and BII. Susceptibility to BXI-arthritis corresponded largely with susceptibility, or resistance, to BII-arthritis. LEW, BB, WF, DA, and WKY were readily susceptible to BXI- and BII-arthritis. Likewise, BII-resistant F344 and BN rats were BXI-resistant. Some strains responded differently to BXI and BII. BUF and COP, which are moderately susceptible to BII, were BXI-resistant, whereas the BII-resistant rats, DA.1N and WF.1N, were partially susceptible to BXI. (F344 x BN) F1 hybrids responded to both collagens suggesting gene complementation. Arthritis occurred in all strains producing the highest titer antisera (LEW, WF and BB). Antibody responses to BXI and BII were generally commensurate within individual strains. DA were susceptible to arthritis but produced low levels of antibody comparable to BN rats which were arthritis-resistant. BXI and BII-susceptibility was variable in rats producing intermediate antibody responses. Antibodies to RXI were detected in all BXI-immunized rats, whereas antibodies to RV and RII were uniformly weaker. DTH to RXI and RII was strong in both groups of rats, correlating poorly with arthritis and antibody responses. These studies show that phenotypic susceptibility to BXI- and BII-arthritis are largely concordant among inbred rat strains but clear differences exist in certain strains; multiple genes are likely involved.

Animals↗
PubMedDate not supplied

[The role of models in economic evaluation of healthcare].

INTRODUCTION: The information on which decision-making in healthcare is based --especially information on new drugs or technologies-- comes mainly from phase III clinical trials, which are carried out according to clinical efficacy criteria. Placebos are frequently used as comparators. Therefore, no clinical or economic evidence is usually available to assess the new product or technology in real-life practice (effectiveness). Efficiency is seldom evaluated either. METHODS: The clinical evidence generated by clinical trials usually evaluates intermediate, not final clinical variables. This makes decision-making difficult, both for clinicians or health-care managers in areas as varied as financing drugs or technology, inclusion of these in a therapeutic formulary or in clinical pathways. CONCLUSION: To obtain clinical and economic information, modelling techniques have been developed in the field of health economics. This study reviews the justification of the use of models, their characteristics, methodological requirements and steps followed for their construction and resolution, while Markov models are explained.

Clinical Trials, Phase III as Topic↗
PubMed1991

Clonal cosegregation of tumorigenicity with overexpression of c-myc and transforming growth factor alpha genes in chemically transformed rat liver epithelial cells.

Tumorigenicity was correlated with levels of expression of the genes for transforming growth factor alpha (TGF-alpha), epidermal growth factor receptor, c-myc, c-H-ras, and c-K-ras in a series of 16 clonally derived transformed liver epithelial cell lines. The clonal lines, which varied in tumorigenicity from 0 to 97%, were established from a phenotypically heterogeneous population produced by repeated exposure of diploid WB-F344 (WB) cells to N-methyl-N'-nitro-N-nitrosoguanidine. Segregation of gene expression with tumorigenicity among clonal lines was determined by correlating rank orders of gene expression by clones relative to expression by wild-type WB cells. Only the expression of the c-myc gene correlated with tumorigenicity among all transformed clones. TGF-alpha gene expression was not correlated with tumorigenicity among all clones, but it was highly correlated with tumorigenicity among clones that expressed the c-myc gene above the median level for all clones (greater than 5-fold the level of expression by WB cells). Even high levels of expression of the TGF-alpha gene (up to 60-fold the level of expression by WB cells) were not correlated with tumorigenicity among the clones expressing the c-myc gene at levels less than 5-fold the level of expression by WB cells. Clones which simultaneously overexpressed both c-myc and TGF-alpha genes at levels above the median levels for all clones were significantly more tumorigenic than were clones which expressed either or both genes at lower than median levels. These results suggest that overexpressed c-myc and TGF-alpha genes cooperate in their association with tumorigenicity. Most of the highly tumorigenic clones that overexpressed c-myc and TGF-alpha also overexpressed the c-H-ras and/or the c-K-ras genes; clones that overexpressed neither of the c-ras genes nor the genes for c-myc and TGF-alpha were not very tumorigenic, while clones that expressed one or both c-ras genes (but not both c-myc and TGF-alpha) were variably tumorigenic over an intermediate range.

Animals↗
PubMedDate not supplied

Methodology for a medical expert system on fuzzy analog ganglionar lattices. Non-approximate reasoning with multiple antecendents of different relative importance and limited uncertainty.

This work presents an Expert System based on fuzzy analog ganglionar lattices. Its reasoning scheme is designed analogously to the expert's mental organization and it is realized on an (analog) operator called the ganglionar lattice. It is a connectionist system that uses the medical knowledge to define its architecture. The operator evokes some similarities to higher order neural networks and performs as the knowledge base and inference engine of the expert system, in a unified manner. A main feature of this operator is that it exhibits the variables corresponding to all intermediate concepts identified by the expert; this characteristic is shown to be most valuable for assessing, explicating and prospecting in medical applications. Further, it is capable of (i) evaluating a consequent for a variety of non-approximate reasonings with multiple antecendents of different relative importance under limited uncertainty; (ii) explicating the conclusions at different levels of abstraction to suit the user; and (iii) prospecting for the best 'a priori' sequence of unevaluated antecedents, from which to choose following tests. These procedures are based on the objective criterion of the consequent's uncertainty decrease (entropy). All results are produced in numerical form and may be translated into restricted natural language. A simple example of this technology is fully developed. Finally the method's potentials are discussed for future applications.

Artificial Intelligence↗
PubMed1996

Race, genetics, and human reproductive strategies.

The international literature on racial differences is reviewed, novel data are reported, and a distinct pattern is found. People of east Asian ancestry and people of African ancestry average at opposite ends of a continuum, with people of European ancestry averaging intermediately, albeit with much variability within each major race. The racial matrix emerges from measures taken of reproductive behavior, sex hormones, twinning rate, speed of physical maturation, personality, family stability, brain size, intelligence, law abidingness, and social organization. An evolutionary theory of human reproduction is proposed, familiar to biologists as the r-K scale of reproductive strategies. At one end of this scale are r-strategies, which emphasize high reproductive rates; at the other end are K-strategies, which emphasize high levels of parental investment. This scale is generally used to compare the life histories of widely disparate species, but here it is used to describe the immensely smaller variations among human races. It is hypothesized that, again on average, Mongoloid people are more K-selected than Caucasoids, who are more K-selected than Negroids. The r-K scale of reproductive strategies is also mapped on to human evolution. Genetic distances indicate that Africans emerged from the ancestral hominid line about 200,000 years ago, with an African/non-African split about 110,000 years ago, and a Caucasoid/Mongoloid split about 41,000 years ago. Such an ordering fits with and explains how and why the variables cluster.

Biological Evolution↗
PubMedDate not supplied

Characterization of intermediate type (WHO "atypical") meningiomas.

The intermediate type meningioma (formerly "meningioma variant with signs of increased proliferation activity"; WHO "atypical" meningioma) represents a meningioma group the mean Ki-67 index and the recurrence rate of which lie between those of the ordinary and the anaplastic type [Kolles et al. 1995]. In the study cited (n = 160) the percentage of recurrences was 9% in the common, 29% in the intermediate, and 50% in the anaplastic type. The present study focuses on 49 subsequently diagnosed meningiomas of the intermediate type. Apart from certain histopathological features, the most important independent factors associated with recurrence were Ki-67 indices covering the 95% confidence interval between 3.7% and 4.9%. At the light-microscopic level, however, meningiomas in general, and especially those supposed to belong to the intermediate type, are highly variable in tissue architecture and do, in contrast to the anaplastic type, not display frank histological features of anaplasia. Morphologically, the growth pattern of solid ("syncytial") sheets, micronecroses, and large distinct nucleoli are suspicious. Cytogenetically, independent of the loss of one chromosome 22, it has been shown that terminal loss of the short arm of one chromosome 1 (1p-) or complete loss of this chromosome were useful additional indicators of meningioma progression.

Adult↗
PubMed1997

Cell type-specific glycoforms of Fc gamma RIIIa (CD16): differential ligand binding.

Fc gamma RIIIa, considered an intermediate affinity receptor, can variably bind monomeric IgG and appears to have a higher affinity for IgG than the lower affinity Fc gamma Rs, Fc gamma RII and Fc gamma RIIIb. We explored this property for both NK cell and monocyte Fc gamma RIIIa and found higher affinity ligand binding by Fc gamma RIIIa expressed on NK cells compared with Fc gamma RIIIa on monocytes. In normal whole blood or plasma (containing 8-11 mg/ml IgG), NK cell Fc gamma RIIIa was fully blocked, but in monocytes Fc gamma RIIIa showed approximately 60% blockade of the binding of mAb 3G8, which binds in or near the ligand binding site. The ligand binding site of NK cell Fc gamma RIIIa was blocked with as little as 2 mg/ml of human IgG, while monocyte Fc gamma RIIIa was only partially (30%) blocked by 2 mg/ml of human IgG. In contrast, plasma containing approximately 26 mg/ml of IgG (obtained from patients receiving therapeutic gamma-globulin) showed complete saturation of monocyte Fc gamma RIIIa with blockade of mAb 3G8 binding. These binding differences are not due to allelic polymorphisms or primary sequence differences between donors. Although NK cell and monocyte Fc gamma RIIIa have identical protein cores, they each undergo differential cell type-specific glycosylation. NK cell Fc gamma RIIIa is glycosylated with high mannose- and complex-type oligosaccharides, while monocyte Fc gamma RIIIa has no high mannose-type oligosaccharides. These results indicate that natural glycoforms of Fc gamma RIIIa (cell type-specific glycosylation variants) bind ligand differently, conferring a lower affinity on monocyte/macrophage Fc gamma RIIIa, which makes the receptor ideal for initial immune complex capture and sensitive to moderate changes in serum IgG levels.

Glycosylation↗
PubMed2001

Psychosocial work characteristics and psychological strain in relation to low-back pain.

OBJECTIVES: This study investigated the relationship between psychosocial work characteristics and low-back pain and the potential intermediate role of psychological strain variables in this relationship. METHODS: The research was part of a prospective cohort study of risk factors for musculoskeletal symptoms. The study population consisted of 861 workers from 34 companies in The Netherlands who had no low-back pain at baseline and for whom data on the occurrence of low-back pain were obtained with annual questionnaires during a 3-year follow-up period. Information on psychosocial work characteristics and psychological strain variables was collected using a questionnaire at baseline. Cases of low-back pain were defined as workers who reported, in at least one of the annual follow-up questionnaires, that they had had regular or prolonged low-back pain in the previous 12 months. RESULTS: After adjustment for individual factors and quantified physical load at work, nonsignificant relative risks ranging from 1.3 to 1.6 were observed for high quantitative job demands, high conflicting demands, low supervisory support, and low co-worker support. Decision authority and skill discretion showed no relationship with low-back pain. In general, the estimated relative risks for the psychosocial work characteristics were scarcely influenced by additional adjustment for job satisfaction, emotional exhaustion, and sleeping difficulties. CONCLUSIONS: It can be concluded that low social support, from either supervisors or co-workers, appears to be a risk factor for low-back pain. Some indications of a relationship between high quantitative job demands and high conflicting demands and low-back pain were also found. Little evidence was found for an intermediate role for the psychological strain variables under study.

Cohort Studies↗
PubMed1987

Reproducibility of myocardial thallium-201 washout in studies applying a standardized dipyridamole stress protocol.

Thallium-201 (201Tl) washout analysis was proposed as an adjunctive tool to improve the detection of coronary artery disease (CAD). Since reproducibility of 201Tl washout in dipyridamole (DPM) stress studies is unknown, this item was evaluated in 32 patients (24 with CAD, 8 without CAD), who were scintigraphed twice within 1-2 weeks. At 2 minutes following DPM infusion (0.5 mg/kg/5 min), 2 mCi 201Tl were injected. Global and segmental washout were calculated by comparing circumferential profiles of respective background-corrected stress (left anterior oblique (LAO) 45 degrees: 8 min postinfusion (p.i.), 35 min p.i.; anterior (ANT): 17 min p.i.; LAO 70 degrees: 26 min p.i.) and redistribution (4 h p.i.) images. Whereas visual findings were comparable for study I and II, reproducibility of 201Tl washout was low, indicated by comparing variances among patients with variance between studies, which were 28.8 and 71.2% of total variance, respectively. Mean differences of segmental washout between the studies ranged from 9.75 to 19.24% with only minor differences with regard to the different views and segments evaluated. Variability was lower using the intermediate instead of the initial scintigram as reference for the redistribution image (12.87 +/- 11.64% vs. 18.59 +/- 14.43%, n = 85; p less than 0.01). Variability was higher for nonstenosed compared to stenosed segments (14.54 +/- 11.41%, n = 32 vs. 9.89 +/- 8.03%, n = 28, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗