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PubMed1990

Variation and classification of human age patterns of mortality: analysis using competing hazards models.

The structure of variation in human mortality patterns is explored using a five-parameter competing hazards model and standard multivariate taxonomic procedures. The data consist of 281 national life tables representing a wide range of environmental and cultural regions of the world. A general or average age pattern of mortality was generated for the entire sample using multiple regression procedures. A K mean cluster analysis conducted on the residuals of the regression analysis identified seven distinct models of mortality that differ in characteristic ways from the general pattern. Four of the seven clusters have age patterns of mortality similar to the north, east, south, and west regions of the Coale and Demeny model life tables. The remaining three clusters represent regions of the world and age patterns of mortality that are not represented in the Coale and Demeny model life tables.

Age Factors↗
PubMed1989

Quantitative analyses of C3b capture and immune adherence of IgM antibody/dsDNA immune complexes.

We isolated the IgM fraction from the plasma of an SLE patient with high titer anti-dsDNA antibodies and prepared soluble IgM/dsDNA immune complexes (IC) that fixed C and captured sufficient C3b to bind to human E via their C3b/C4b receptor, CR1 (immune adherence, IA). We used specific 125I-labeled mAb to IgM, C3b, and IgG to measure the stoichiometries of these C-opsonized IC. They contained 10 to 60 C3b and 10 to 30 IgM per PM2 dsDNA, had no detectable IgG, and the vast majority of the C3b was bound to the IgM, and not to the dsDNA. These stoichiometries are in contrast to those we observed for comparable E-bound IC prepared with IgG anti-dsDNA antibodies (100 to 200 C3b, and 200 to 500 IgG). Our results help explain the greater lability of the IgM IC with respect to IA as evidenced by their plasma-mediated release from human E (presumably due to factor I), and confirm previous predictions of a lower density of "packing" of IgM on dsDNA, compared to IgG. The detailed stoichiometry of C3b capture by the IgM IC (typically 1.5 to 3 C3b per IgM) suggests that individual IgM molecules with multiple C3b facilitate IC binding to clusters of CR1. Finally, comparison of the IgM/dsDNA IC with other IgM IC which have been investigated with respect to C activation, and review of the proposed mechanism by which IgM activates C, suggests that the nature of the Ag plays a fundamental role in determining whether or not an IgM IC can activate C and participate in IA.

Antigen-Antibody Complex↗
PubMed1989

[Adenocystic cancer of the breast (clinico-morphologic characteristics)].

Examination of two adenocystic carcinomas of the mammary gland has revealed main criteria for the morphological diagnosis of this malignant tumor. This is characterized by the presence of cribrose structures that are formed by multiple pseudocysts filled with amorphous substance. Clusters of small, monomorphic, cubic cells with round or oval nuclei form abundant islets at whose expense a characteristic sieveform pattern develops. The myoepithelial cells are frequently detected in the tumor. A favorable prognosis is seen in adenocystic carcinoma of the mammary gland. The two patients are alive having no signs of disease progression in their 9- and 51-month follow-up, respectively.

Adult↗
PubMed1985

Effect of pH on the morphology of Staphylococcus aureus.

Nineteen strains of Staphylococcus aureus (10 sensitive and 9 resistant to oxacillin) were grown for four hours on membranes placed on trypticase soy agar at pH 5, 5.5, 6, 6.5, 7.1, 7.5, 7.8 and 8.3. The morphology was observed by interference phase contrast and by electron microscopy. All strains grown at pH 6 to 7.5 produced cocci of normal size. When grown at pH 5, 5.5, 7.8 and 8.3, however, seven of the oxacillin-resistant strains and seven of the oxacillin-sensitive strains produced bacterial cells 1.5 to 2 micron in diameter. These cells consist of a cluster of staphylococci held together by multiple thick cross walls. Their structure is similar to that of staphylococci grown in the presence of subminimum inhibitory concentrations of beta-lactam antibiotics, which inhibit autolysis of cross walls. It appears that autolysis of cross walls of S. aureus is also inhibited by a low or a high pH.

Autolysis↗
PubMed1984

[Biological evaluation of the aggressiveness of copper slag dust].

By hemolytic, intraperitoneal and intratracheal tests, biological effects of the copper slag dust, which has recently been used in casts cleaning processes, have been investigated. It was found that the copper slag dust is not biologically inert. It exhibits slight fibrogenic properties resulting in fibrous changes after lung administration. The fibrosis resembles that of collagenosis. The fibrous reaction, in form of granulomas with developed procollagenic fibres, was found on intraperitoneal dust administration. Three and six months after intratracheal insufflation of 50 mg of the dust a significant increase in the content of hydroxyproline and lipids in lungs, as compared to controls, was found. Histopathological test revealed the connective tissue multiplication, of focal type, around dust clusters, forming granulomas consisting of macrophages and other mononuclear cells. In the hemolytic test the slag dust induced hemolysis of 7% ram erythrocytes. The test dust should be classified as weakly fibrogenic.

Animals↗
PubMedDate not supplied

Factors related to success and failure rates at 3-year follow-up in a multicenter study of overdentures supported by Brånemark implants.

An international prospective study of Brånemark implants retaining overdentures was conducted at nine clinical centers. One hundred thirty-three subjects were recruited in a 12-month period and provided with 510 implants, 117 of which were in maxillae and 393 were in mandibles. This study reports the 3-year follow-up status of 120 overdentures and 444 implants. There were 11 overdenture failures (9.2%). Maxillary overdenture failure rates (27.6%) were nearly nine times greater than mandibular overdenture failure rates (3.3%). Maxillary overdenture treatment was less successful than previously reported fixed implant-supported restorations. However, their mandibular counterparts had success rates slightly higher than those reported for fixed implant-supported restorations. At 3 years, 150 implants remained submerged and 66 implants had been withdrawn because the subjects discontinued study participation. Eleven mandibular and 29 maxillary implants had failed and had been removed from 21 subjects. Logistic regression with forward model selection indicated that one two-way interaction was significantly related to implant failure. At highest risk were the subjects who possessed dental arches with bone quantity E and bone quality 4. Subjects with one implant failure were likely to have more than one failure. The Generalized Estimating Equation was used to adjust for the cluster effect in this population because multiple implants (2 to 6) were placed and evaluated in each of the 133 subjects.

Adult↗
PubMed1995

Fibroblastic rheumatism.

BACKGROUND: Fibroblastic rheumatism was first described in the French literature in 1980. Since that time, 11 other patients with this disorder have been identified in the literature, mostly from France. This is a unique syndrome characterized by the sudden onset of symmetric polyarthritis and cutaneous nodules ranging from 5 to 20 mm in diameter, with predilection for the upper and lower extremities. While the cutaneous findings resolve spontaneously after several months, permanent joint sequelae are common. OBSERVATIONS: We present the first two patients with fibroblastic rheumatism reported in the United States. The clinical features and histologic findings were identical to those of patients described in the European literature. CONCLUSIONS: Fibroblastic rheumatism is a relatively rare syndrome characterized by the association of multiple cutaneous nodules with polyarthritis. The clustering of cases in France may, in part, be attributable to increased recognition by clinicians owing to prevalence of reports in the European literature. Perhaps, as clinicians in the United States become familiar with this disorder, further cases will be diagnosed, and the pathogenesis of the disorder will be elucidated.

Arthritis↗
PubMedDate not supplied

[The recurrent multifocal pleomorphic adenoma].

Pleomorphic adenoma (P.A.), the most common tumor of the salivary gland, demonstrates a peculiar clinicopathological behaviour for numerous reasons: the high recurrence rate following primary surgery (up to 50%), the appearance of malignancy (2-9%), the reported number of distant metastases histologically identical to the primary P.A. From among 71 cases of benign parotid tumors treated from Nov. 89 to Nov. 92 in the ENT Department of "Regina Elena", the National Cancer Institute in Rome, six particular cases showed multiple force of P.A. recurring after primary surgery performed from 3 to 32 years previously and are object of discussion in this study. All of these six cases had multiple recurrences, usually manifest as nodular clusters in the parotid area, while in three cases appeared as well a recurrence in the soft tissue of the neck, far removed from the parotid space, with no involvement of neck nodes as was revealed through histological examination following neck dissection. A hypothetical mechanism of diffusion is discussed. The Authors agree with the opinion which holds the surgeon's inability to successfully eradicate primary tumors responsible for the high frequency of recurrences. The surgical technique of "enucleation" is, in fact, inadequate in P.A. excision owing the high risk of mishandling or rupturing the tumor capsule with a consequent seeding of the tumor onto the surgical bed. Lateral lobectomy, with identification of the facial nerve, or total conservative parotidectomy (for deep lobe adenoma) are correct techniques in treating primary P.A.. The Authors also discuss management of recurrent P.A. in relation to facial nerve involvement. Preservation of the seventh nerve with eventual post-operative radiation should be considered an alternative to nerve sacrifice in selected cases of recurrent pleomorphic adenoma.

Adenoma, Pleomorphic↗
PubMed1993

[Erythrocyte CR1 receptor: binding and transport of immune complexes in the blood circulation].

Immune complexes (IC), after reacting with the complement system, bear C3b fragments (opsonized IC) and bind to the CR1 receptor that is present on human erythrocytes (CR1 = complement receptor type 1). This efficient binding reaction prevents random vascular IC deposition, and allows IC to be transported through the circulation to the fixed macrophage system of the liver and spleen, where they are safely eliminated. The structure of CR1, with multiple C3b binding sites, and the clustered distribution of CR1 on the erythrocyte surface favor the multivalent binding of opsonized IC to erythrocytes. CR1 on erythrocytes serves as a cofactor for the inactivation of C3b by factor I, thus allowing the release of IC from the erythrocyte surface and their transfer to fixed macrophages. Under normal circumstances, the erythrocyte plays a major role in the processing of IC in humans.

Antigen-Antibody Complex↗
PubMed1998

Staphylococcal enterotoxin D is a promiscuous superantigen offering multiple modes of interactions with the MHC class II receptors.

Dimerization of MHC class II molecules on the cell surface of human THP-1 monocytic cell line is a requirement for staphylococcal superantigen (SAG)-induced cytokine gene expression. The capacities of various SAG to induce this response are governed by their modes of interaction with MHC class II molecules. Staphylococcal enterotoxin A (SEA), with its two binding sites, dimerizes MHC class II molecules and subsequently induces cytokine gene expression in THP-1 cells. Here, we demonstrate that staphylococcal enterotoxin D (SED) and staphylococcal enterotoxin E (SEE) induce, similarly, IL-1beta and TNF-alpha gene expression in these cells. Using mutated toxins that lost their binding site with the MHC class II alpha- or beta-chain, we demonstrate that this response is also mediated by the dimerization of MHC class II molecules through two binding sites. Furthermore, SED forms Zn2+-dependent homodimers that allow multiple modes of MHC class II clustering, including ligation of alpha-chains (alpha/alpha), beta-chains (beta/beta), or the alpha- and beta-chains of two different class II molecules. The beta/beta interaction following Zn2+-dependent SED/SED homodimer formation seems to be mediated by the appearance of a novel binding site on SED that interacts with histidine 81 of the MHC class II beta-chain. The different modes of SED interactions also influence SED-induced T cell activation where simultaneous ligation of the alpha- and beta-chains is essential for optimal response. These various modes of SED binding may be used to preserve bivalency regardless of variability in the MHC class II alpha/beta/peptide complexes.

Binding Sites↗
PubMed1998

Lipidation as a novel approach to mucosal immunization.

We describe the design and development of a novel peptide-based approach for mucosal immunization. The design contains an amplified peptide chain as multiple antigen peptide (MAP) with a cluster of lipids. Such a design would confer on lipidated MAP the ability to self-assemble in water, mimicking enveloped viral particles. The importance of lipidation for mucosal immunization was confirmed by oral immunization with lipidated MAP in phosphate-buffered saline (PBS), which induced mucosal and systemic immune responses at local and distant sites, including sera and vaginal IgG as well as secretory IgA in saliva, vaginal secretions and fecal matter. T-cell proliferative responses were found in spleen, Peyer's patches and genital lymph nodes. In addition, significant splenic cytotoxic T-cell responses were also observed. No significant immune responses were observed with non-lipidated MAPs by oral delivery in PBS. Furthermore, these responses were selectively enhanced by different regimens, systemic priming and microparticle delivery. These results demonstrate the effectiveness of lipidated MAP for mucosal immunization to evoke both systemic and mucosal immune responses without the use of carrier or extraneous adjuvant.

Administration, Oral↗
PubMed1987

Children's use of multiple-counting skills: adaptation to task factors.

The purpose of the study was to determine conditions under which young children enumerate by counting in multiples. Thirty-eight kindergartners and first-graders enumerated dot displays and gave verbal reports of their strategies; additionally, they were given an independent assessment of multiple-counting skill. Dot displays varied according to overall numerosity, perceptual arrangement (random, clustered, rectangular), and numerosity of subgroupings. Children were relatively accurate at enumerating small-numerosity and nonrandom displays. They were relatively likely to report counting by multiples, rather than by ones, on small-numerosity and clustered displays. Contingent upon their skill level, children counted by multiple units (twos, threes, and fours) that corresponded to the numerosity of subgroupings (2, 3, and 4). Contrasting effects of different numerosities and perceptual arrangements are discussed in terms of contextual support for the use, and development, of numerical skills among young children.

Child↗
PubMed1995

Multiple Tandemly Repeated Binding Sites for the YY1 Repressor and Transcription Factors AP-1 and SP-1 Are Clustered within Intron-1 of the Gene Encoding the IE110 Transactivator of Herpes simplex Virus Type 1.

Expression of the IE110 (ICP0) transactivator protein of HSV appears to be critical for reactivation from the latent state and occurs at immediate-early times during the lytic cycle under the control of an upstream divergent enhancer-promoter region that contains multiple Oct and Sp-1 binding sites overlapping with VP16 response elements. Surprisingly, the large 800-bp first intron of the HSV-1 IE110 gene also proved to have a complex repetitive organization encompassing multiple transcription factor binding sites within four distinct domains. DNaseI footprinting studies revealed that 13 of 17 copies of a 15-bp repeated element represented high-affinity binding sites for the cellular YY1 repressor protein. Between 4 and 7 of these sites are direct tandem repeats and the rest are interpersed with three repeated AT-rich motifs and a dyad symmetry region containing two strong AP-1 binding sites and an adjacent SP-1 binding site on each arm. Several of the YY1 sites also bound weakly to SRF. The intron also contains four clustered purine/pyrimidine tracts of between 16 and 23 bp long. Both the AP-1/AP-2/SP-1 dyad protein binding region and, to a lesser extent, the YY1 tandem-repeat cluster conferred responsiveness to TPA when placed upstream of a heterologous promoter in transient expression assays. The functional significance of the HSV-1 IE110 intron region is unknown as yet, but the novel arrangement of tandemly repeated YY1 sites has the potential to produce structural bending and transcriptional attenuation effects. Interestingly, few of these transcription factor binding motifs are conserved in the equivalent IE110 intron of HSV-2, and the domain appears to represent a unique alternative control region that is specific for HSV-1. Copyright 1995 S. Karger AG, Basel

Journal Article↗
PubMed1989

Spectroscopic characterization of the iron-sulfur cluster in Bacillus subtilis glutamine phosphoribosylpyrophosphate amidotransferase.

The properties of the [4Fe-4S] cluster in glutamine phosphoribosylpyrophosphate amidotransferase from Bacillus subtilis have been investigated using low temperature magnetic circular dichroism, electron paramagnetic resonance (EPR), and resonance Raman spectroscopies. The Raman spectra of the native enzyme in the Fe-S stretching region show a [4Fe-4S]2+ cluster that is structurally very similar to those in simple redox proteins. Photochemical reduction mediated by 5-deazaflavin with oxalate as the electron donor resulted in [4Fe-4S]+ clusters with a mixture of ground state spin multiplicities. Magnetic circular dichroism and EPR studies of samples ranging in concentration from 0.15 to 0.4 mM concur in finding S = 3/2 [4Fe-4S]+ clusters with predominantly axial and positive zero field splitting as the dominant species. The EPR studies also revealed minor contributions from S = 1/2 [4Fe-4S]+ centers and an S = 5/2 species. The latter becomes the dominant component in more concentrated samples (approximately 2 mM), and arguments are presented in favor of assignment to S = 5/2 [4Fe-4S]+ clusters rather than adventitiously bound high spin Fe(III) ions. The concentration-dependent spin state heterogeneity of the [4Fe-4S]+ cluster in glutamine phosphoribosylpyrophosphate amidotransferase is discussed in light of the magnetic and electronic properties of the [4Fe-4S]+ centers in other enzymes and proteins.

Amidophosphoribosyltransferase↗
PubMed2002

Concordance of disease form in kindreds ascertained through affected individuals.

When designing or conducting genetic epidemiological studies of a disease with several distinct forms, it is useful to know whether susceptibilities to the different forms are conferred by different genes or whether there are genes that confer susceptibility to multiple forms. A natural approach to exploring these issues is to examine how the disease forms cluster in kindreds. When inclusion in the study is based on the affection status of multiple relatives, however, distorted patterns of familial clustering of disease form can be evident. The purpose here is to present statistical methods for adjusting for this distortion. In particular, approaches to testing two null hypotheses are presented: a null hypothesis that corresponds to all genes acting in the same way on the relative risk of the different disease forms, and a null hypothesis that corresponds to each gene conferring susceptibility to distinct disease forms. The approaches are illustrated through an application to the generalized and localization-related forms of epilepsy.

Cluster Analysis↗
PubMed2006

Multiple C-H bond activation in group 3 chemistry: synthesis and structural characterization of an yttrium-aluminum-methine cluster.

Complete donor-induced alkylaluminate cleavage of halfmetallocene complex Cp*Y(AlMe4)2, that is, treatment of Cp*Y(AlMe4)2 with 2 equiv of diethyl ether, produces [Cp*Y(mu2-Me)2]3 in high yield (95%). In contrast, the equimolar reaction of Cp*Y(AlMe4)2 with diethyl ether reproducibly formed complex [Cp*4Y4(mu2-CH3)2{(CH3)Al(mu2-CH3)2}4(mu4-CH)2] in low yield (10-30%) via a multiple C-H bond activation. The synthesis of the heterooctametallic yttrium-aluminum-methine cluster was also accomplished in moderate yield (47%) by the equimolar reaction of discrete Cp*Y(AlMe4)2 and [Cp*Y(mu2-Me)2]3 in the absence of any donor solvent and "free" AlMe3. This gives strong evidence that preformed heterometal-bridged Y-CH3-Al moieties are prone to multiple hydrogen abstraction in the presence of a highly basic reagent such as [Cp*Y(mu2-Me)2]3. The monocylopentadienyl complexes [Cp*Y(mu2-Me)2]3 and [Cp*4Y4(mu2-CH3)2{(CH3)Al(mu2-CH3)2}4(mu4-CH)2] were structurally characterized.

Journal Article↗
PubMed1988

Relationship of subgingival microbial complexes to clinical features at the sampled sites.

Subgingival plaque samples from 100 active destructive periodontal lesions and 150 inactive subgingival sites in 33 subjects were analyzed by predominant cultivable microbiota techniques. 50 isolates were characterized from each sample and where possible, the isolate was placed in 1 of 134 microbial species or groups. The sites were clustered on the basis of the proportions of all of the species detected in each sample using a minimum similarity matching coefficient and an average unweighted linkage sort. 10 clusters containing 166 sites were formed which exhibited greater than 35% minimum similarities. All clusters were made up of sites from multiple subjects and were formed on the basis of different combinations of micro-organisms. Certain complexes of micro-organisms appeared to relate to the severity of periodontal destruction and the activity of the sampled site. The combination of F. nucleatum, B. forsyth and W. recta (cluster VII) or B. gingivalis, B. intermedius and S. intermedius (cluster VIII) distinguished clusters made up of sites which on average had the most attachment loss and the deepest pockets. These clusters contained the highest proportions of active sites and sites which lost greater than 3 mm of attachment after therapy. Clusters dominated by V. parvula (cluster III), the Actinomyces sp. (cluster X) or the combination of S. sanguis II, S. mitis, V. parvula and S. intermedius (cluster II) were made up of sites which exhibited less active disease and responded more favorably to therapy. Sites in other clusters exhibited moderate levels of prior destructive disease and disease activity status closer to the mean values for all 250 sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2005

[Study on the relations between overweight, obesity, blood pressures, serum lipids and glucose in schoolchildren of Shijiazhunag].

OBJECTIVE: To explore the clustering character of overweight and obesity with multiple cardiovascular disease risk factors such as blood pressure, serum lipids and glucose, and to provide evidence for intervention in childhood. METHODS: A cross-sectional study was conducted on 913 children aged 7-13 years in urban area of Shijiazhuang. Measurements included height, weight, systolic blood pressure (SBP), diastolic blood pressure (DBP) and fasting serum total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and serum glucose (GLU). RESULTS: Overall prevalence rate of overweight and obesity was 29.24% (boys: 34.98% vs. girls: 24.23%). When compared with normal children, children with overweight or obesity had significantly higher levels of SBP, DBP, TC, TG but low HDL-C. The prevalence rates of high SBP, DBP, TC, TG, GLU and low HDL-C in overweight and obese children were higher than in normal children. After adjusted for gender and age, the odds ratios of overweight and obese children for high SBP, DBP, TC, TG, GLU and low HDL-C were 6.77, 3.22, 2.55, 6.42, 3.85 and 2.94 (95% CI: 4.15-11.04, 1.38-7.49, 1.59-4.11, 3.46-11.92, 1.69-8.78 and 1.83-4.73), respectively. Odds ratios of overweight and obese children holding any one, two or three of the selected six risk factors appeared to be 2.74, 13.15 and 15.33 (95% CI : 1.92-3.92, 6.69-25.87 and 4.17-56.39), respectively. CONCLUSION: Childhood overweight and obesity increased the clustering of children's risk factors on cardiovascular diseases, as well as increasing the risk of children acquiring multiple cardiovascular disease risk factors. Controlling overweight and obesity would help early prevention on children from getting cardiovascular diseases.

Adolescent↗