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PubMedDate not supplied

[An introductive approach to linguistics (author's transl)].

The author proposes an information on the semiological approach to language starting from the systemic perspective (later to be said structuralist) which has been introduced by the Saussure. A group of notions can be delineated, which are distributed in binomial oppositions: language and verb, synchronia and diachronia, meaning and signified (which define the linguistic sign, which arbitrary character is being discussed) and other oppositions. The descriptive study of linguistic units of the chain concerns phonetics and phonology. The regulations for constructing a coherent message concern grammar (or syntax), where the traditional, normative approach is in opposition with actual research, descriptive and structural: distributionnal grammar, transforming, categorial, functional. The application of new linguistic methods to human sciences is very promising and opens the way of an interesting meditation on human condition.

Linguistics↗
PubMed1981

A probability mixture model of completed parity.

This research was designed to find a probability model that would adequately describe completed parity for women in populations characterized by high fertility combined with high zero parity. A negative binomial mixture distribution was adapted for this purpose. The form of this distribution suggests the hypothesis that human populations consist of two subgroups of women with respect to completed parity, defined according to whether they do or do not produce viable offspring. Results of the present research further suggest that the proposed distribution for completed parity has general applicability across human populations, whether they are of a high or low fertility type, and whether they have a high or low zero parity.

Female↗
PubMed1995

Tests for genetic linkage and homogeneity.

This report concerns likelihood ratio tests in a heterogeneous model for linkage, where the recombination fraction has a binomial mixture distribution with an unknown proportion of unlinked families. We consider families of unequal sizes with known or unknown phase data. In both cases, the limit distributions of the linkage test statistics are a mixture of a mass at ) and of a X2/1 distribution in equal proportions and homogeneity test statistics tend to the supremum of Gaussian processes. The critical values of the homogeneity tests are simulated, and the power functions of the linkage and homogeneity tests are compared in a simulation study.

Biometry↗
PubMed1994

[Genetic basis of idiopathic epilepsy in the golden retriever].

The genetic aspect of idiopathic epilepsy in the Golden Retriever was examined. 336 pedigrees of a population of normal and epileptic dogs from five different generations were statistically evaluated. Most patients showed generalized Grand-mal seizures and the onset was within one to three years in 75% of the dogs. A significant sex predisposition for males was found. The increased manifestation of seizures in some subpopulations and the repeated occurrence in different families of the same sires revealed that there is a genetic basis for the condition of this breed. The results of pedigree analyses and binomial test support the hypothesis of an autosomal multifactorial recessive mode of inheritance. However, only an objective test-mating programme is likely to delineate the exact mode of inheritance.

Age Factors↗
PubMed1993

CD4 lymphocytopenia among injecting drug users in New York City.

Recent cases of "AIDS-like" CD4 lymphocytopenia in the absence of HIV infection have generated considerable scientific and public interest. We studied CD4 cell counts and percentages from 1984 to 1992 among 1,246 HIV-seronegative injecting drug users in New York City, a population at very high risk for exposure to bloodborne pathogens. Severe CD4 lymphocytopenia was rare, and there was no evidence of an increase over time. Of 229 subjects with longitudinal data, only four met the surveillance definition for "idiopathic CD4 lymphocytopenia" (ICL). CD4 cell counts of < 500 cells/microliters were, however, associated with subsequent HIV seroconversion (12.7/100 person-years at risk, relative risk (RR) = 4.53, 95% exact binomial confidence interval (CI) 1.7-10.7, p = 0.002).

Adult↗
PubMed1994

Excess positive associations in communities of intestinal helminths of bats: a refined null hypothesis and a test of the facilitation hypothesis.

The null hypothesis that the number of positive pairwise covariances should equal the number of negative pairwise covariances in samples from communities of randomly associated helminth species was reevaluated. The proportion of positive covariances in a sample from a community of independent species depends upon the proportion of rare species (prevalence less than 10%), the proportion of common species (prevalence greater than 90%), and the size of the sample of hosts. If rare species dominate, then there will be an excess of negative associations; if common species dominate there will be an excess of positive associations. Many helminth communities have more rare than common species, therefore samples from communities that show an equal number of positive and negative covariances have a greater number of positive associations than is expected for randomly associated species. Increased sample size will reduce the sampling bias, but at least 100 hosts are necessary and often 500-7,500 hosts are required. The excess of positive covariances between helminth species in 10 populations of bats disappeared after restricting the analyses to hosts in which both members of a species pair were present. This result suggests that excess positive associations between helminth species in bats are due to joint presences and absences in hosts rather than to interspecific facilitation. Interspecific facilitation would be supported by observed positive correlations between the intensities of individuals of the species pairs.

Analysis of Variance↗
PubMed1993

Postoperative bleeding tendency as a risk factor in Actinobacillus actinomycetemcomitans-associated periodontitis.

Frequent bleeding on probing (BOP) has been considered a risk factor for recurrence of periodontitis. In the present study, 29 patients with Actinobacillus actinomycetemcomitans-associated periodontitis were enrolled in a carefully performed recall system. At 6 sites per tooth, periodontal probing depth (PPD), gingival index (GI), plaque index (PlI) and BOP was assessed 6 weeks, 6 months, 1 and 2 years after comprehensive therapy. Professional toothcleaning and subgingival scaling at sites with PPD > or = 5 mm and BOP was carried out every 2nd or 3rd month. Subgingival samples from 2 sites, a pooled subgingival sample, cheek mucosa, saliva and tongue samples were selectively cultivated for A. actinomycetemcomitans after 2 years. Following active therapy, 8% sites had a PPD of > or = 4 mm, whereas 21% sites bled on probing. After 2 years, respective figures were 12 and 27%. During maintenance, frequent BOP (> or = 3 times at 4 visits) had a predictive value of 0.133 to indicate an increase in PPD of > or = 2 mm and a negative predictive value of 0.947. The predictive value of no bleeding to indicate a stable site was 0.972, the negative predictive value 0.078. There was evidence for heterogeneity of associations between increase in PPD of > or = 2 mm and > or = 3 times BOP among patients (chi 2(28) = 41.45, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Frequency and chronology of occurrence of anti-HCV in non-A non-B post-transfusional hepatitis.

OBJECTIVE: Studying the frequency and timing of the appearance of the virus C antibody. PATIENTS: We studied serum samples of 57 patients whom developed post-transfusional non-A non-B hepatitis. 34 males, and mean age was 47.56 +/- 13.45 years. Initially anti-HVC was detected by ELISA, and the test was repeated on the last negative sample and the first two positive ones of each patient. RIBA-I and 2nd generation ELISA were performed on these same samples. HCV polymerase chain reaction was performed in 5 seronegative patients by the other techniques. RESULTS: Fifty patients (87.5%) seroconverted to anti-HCV; 26 (52%) within 30 days after the onset of the disease (11 during incubation period); and, 24 (48%) seroconverted after the first month of the disease. Anti-HCV negative patients had lower transaminase levels. Twenty six (52%) of the 50 patients showing seroconversion developed a chronic hepatitis, while this occurred in two (28.5%) of the seven seronegative patients (this difference was not statistically significant). Determination of HCV-RNA by polymerase chain reaction, performed (eight years after the onset of the disease) in 4 of the five seronegative patients by ELISA and RIBA techniques, was negative. Nowadays one of them is anti-HCV and HCV-PCR positive and sustain normal transaminases values. CONCLUSIONS: 87.5% of post-transfusional non-A non-B hepatitis seroconverted during the follow-up. 26 (52%) showed this within 30 days after the onset of their disease; of this group, 11 became seropositive before their ALT values rose. Nowadays in all patients (except one) initially seronegative, in which polymerase chain reaction was performed, negative serology results persist. There were no clinical and evolution differences between the groups.

Adult↗
PubMed1993

Effects of dentin age and bonding on microgap formation.

This study compared the effectiveness of dentin adhesives in extracted molars from younger (16-26) and older (58-87) human subjects. Extracted molars were selected to be restored with one of two dentin bonding agents (n = 22 per group). Opposite sides of each molar were ground flat and a 3 mm x 3 mm cylindrical preparation was milled into each surface. The opposing surfaces of each molar were then randomly restored with either a dentin bonding system that adhered to the dentin smear layer or one which bonded to the dentin after the smear layer was removed. All samples were examined at x150 to determine both the maximum gap in micrometers and extent of the gap in degrees. There were significantly shorter (P < 0.05) microgaps in older dentin with a bonding system that removed smear layer. This bonding system also produced shorter gaps in older dentin than in younger dentin. However, there was no statistically significant difference in the percentage of gap-free margins between age groups.

Adolescent↗
PubMed1993

On statistics of success and loss for dental implants.

Assessments of implantation success have mainly been based on incorrect statistical methods: the binomial approach of percentage of implants not failed-to-date over inserted implants. The survival or life-table approach, instead, adjusts individually for duration of exposure (from insertion until explantation or last recall examination). If published failure percentages are adjusted for mean time of follow-up, which is reported in at least some papers, and a lower 95 per cent-confidence bound on the failure rate is calculated, considerably lower probabilities of one, two or more years of survival will be obtained in many cases. An analysis of 2,292 implants yielded a pre-prosthetic 6-months survival probability between 87 and 91 per cent. The post-prosthetic 2-years survival for pillar-shaped (n = 314 with single tooth replacements) and screw implants (n = 150 with edentulous jaws and one implant, randomly chosen, per patient) may be between 79 and 89 per cent and 79 to 96 per cent, respectively (95 per cent-confidence intervals). In pillar-shaped implants, there is preliminary evidence that ceramic implants and male patients carry a larger risk of failure than metal implants and female patients. With screw implants, only high patient age at implantation may be a risk factor.

Analysis of Variance↗
PubMed1993

Heritability estimations of osteochondrosis in the tibiotarsal joint and of bony fragments in the palmar/plantar portion of the metacarpo- and metatarsophalangeal joints of horses.

Radiography of the tibiotarsal and metacarpo- and metatarsophalangeal joints was performed on 753 Standardbred trotters (6 to 21 months old) born in 1988. The surveyed population was drawn at random from all parts of Norway and represented about 60% of Standardbred trotters born the same year. Osteochondrosis in the tibiotarsal joint was diagnosed in 108 (14.3%) horses, and the prevalence of disease in progeny groups > 10 ranged from 0 to 69%. Bony fragments in the palmar/plantar portion of the metacarpo- and metatarsophalangeal joints were diagnosed in 89 (11.8%) horses, and the prevalence of disease in progeny groups > 10 ranged from 0 to 41%. Heritability analysis was restricted to 644 horses, comprising groups of 5 or more progeny, from 39 stallions. The heritabilities of osteochondrosis in the tibiotarsal joint and of bony fragments in the palmar/plantar portion of the metacarpo- and metatarsophalangeal joints were estimated to be 0.52 and 0.21, respectively, using a nonlinear model.

Animals↗
PubMed1993

How can the assessment of the hemodynamic significance of aortoiliac arterial stenosis by duplex scanning be improved? A comparative study with intraarterial pressure measurement.

PURPOSE: The current diagnostic criteria used to assess the severity of stenoses in the aortoiliac arteries by duplex scanning are mainly based on information related to changes in cross-sectional area and are flow independent. Consequently, duplex scanning fails to detect approximately one quarter of hemodynamically significant aortoiliac lesions compared with intraarterial pressure measurements. The aim of this study is to improve the assessment of the hemodynamic significance of aortoiliac lesions by duplex scanning. METHODS: A prospective study in 60 patients was performed in which duplex scanning at rest was compared with intraarterial pressure measurements before and after the administration of papaverine. A simplified Bernoulli equation was used to calculate pressure gradients across stenoses (delta PBern). Two flow-related parameters, the increase in peak systolic velocity (delta PSV) across the stenosis and the end-diastolic velocity at the site of the stenosis, were also measured and compared with intraarterial pressure measurements. RESULTS: delta PBern and delta PSV showed a sensitivity and specificity of 81% and 88%, respectively, for the detection of hemodynamically significant lesions at rest. However, delta PBern could often not give an accurate calculation of the pressure gradient. Receiver operator characteristic analysis showed that a cut-off level for delta PSV in the range of 1.4 to 1.5 m/s was best able to detect significant lesions at rest. The end-diastolic velocity parameter had a limited diagnostic value. CONCLUSION: Although useful in clinical decision making, delta PBern often could not give an accurate calculation of the pressure gradient. delta PSV is a simple and practical spectral analysis parameter to differentiate between significant and insignificant stenoses. This parameter also has the potential to detect hemodynamically less critical lesions if duplex scanning is performed under conditions of increased flow. Further evaluation is needed.

Aorta, Abdominal↗
PubMedDate not supplied

[The embryonic brain-derived neuralizing factor (EBDNF): its partial purification by ion-exchange and affinity chromatography].

The data are presented about isolation from the brain of 7.5-day chick embryos of a factor capable of neuralizing effect on the early gastrula ectoderm of the grass frog Rana temporaria L. Earlier this factor was defined as embryonic brain-derived neuralizing factor (EBDNF) (Mikhailov, Gorgoliuk, 1989). The isolation procedure includes (1) extraction with deionized water at pH 9.0; (2) ion exchange chromatography on a column with DEAE-adsorbent at pII 8.0; (3) affinity chromatography on Heparin-Ultragel column. EBDNF-containing fraction is eluted from the Heparin-Ultragel column with 250 mM NaCl as a separate peak. Four bands are observed on SDS-electrophoregrams of this fraction, two more prominent ones having the molecular weight of 43 and 63 kDa. The yield of EBDNF-containing fraction is about 0.01-0.02% of the wet weight of the initial brain tissue.

Animals↗
PubMed1993

Analysis of embryonic development with a model for under- or overdispersion relative to binomial variation.

Observations from a study of the development of ovulations into embryos for Texel sheep are analysed with a model for count data that are under- or overdispersed relative to binomial variation. The analysis is based on maximum quasi-likelihood (McCullagh and Nelder, 1989, Generalized Linear Models, 2nd edition, London: Chapman and Hall), following an approach suggested by Williams (1982, Applied Statistics 31, 144-148). The dispersion parameter is developed as a combination of a variance component representing shared maternal effects and a correlation, typically negative, between ovulations within ewes. The number of ovulations (the binomial denominator) is included as an explanatory variable.

Androstenedione↗
PubMed1996

The tumor biology of melanoma nodal metastases.

Approximately 20 per cent of melanomas greater than 0.76 mm in thickness will metastasize to the regional lymph nodes if treated with wide local excision alone (WLE). Elective lymph node dissection (ELND) is associated with significant morbidity, which includes lymphedema, wound complications, and paresthesias of the extremity. An alternative operative approach uses selective lymphadenectomy with the identification of the sentinel node, defined as the first node in the lymphatic basin that drains the primary cutaneous site. This study consisted of 132 patients with melanomas greater than 0.76 mm. One hundred nine patients (83%) had histologic negative sentinel nodes, and 23 patients (17%) had one or more sentinel nodes positive for disease. In patients with metastatic disease, 30/35 (86%) sentinel nodes were positive, and 25/357 (7%) nonsentinel nodes were positive (P < 0.001). In 18 patients (78%) of the 23 patients with metastatic disease, the sentinel node was the only node positive, strongly suggesting that there is an orderly progression of metastases. Two patients developed metastatic nodal disease after removal of a negative sentinel node (false negative rate = 1.5). The mean follow-up was 1 year. Sentinel node histology reflects the histology of the remainder of the nodes in the lymphatic basin and "skip" metastases, defined as a negative sentinel node but positive nodes higher in the regional chain positive for metastases or an axillary recurrence after a negative sentinel node biopsy, are rare for malignant melanoma. Harvesting the sentinel node in patients with intermediate or greater thickness melanoma will, therefore, identify a subset of patients with metastatic disease who have the most to benefit from a complete node dissection. This surgical approach allows for complete pathological staging and therapeutic management of patients while significantly reducing expense and overall morbidity.

Adolescent↗
PubMed1996

Modeling conception as an aggregated Bernoulli outcome with latent variables via the EM algorithm.

We describe a general method for analyzing aggregated Bernoulli outcomes. The research is motivated by an epidemiological reproductive study where the outcome was whether pregnancy was detected in a woman's particular menstrual cycle and the Bernoulli "trials" corresponded to days with intercourse during the cycle. Each cycle is either "viable" or not, i.e., is or is not susceptible to conception. We develop an EM algorithm approach to maximizing the observed-data pseudo-likelihood, based on a set of unobservable latent outcomes linked to the specific days with intercourse. This method is flexible in that it allows one to model effect of covariates on the susceptibility factor and on the latent outcomes. Application of the method to fertility studies enables one to investigate covariates with a long-term or transient effect on the daily conception probability. A complication is that most couples contribute more than one cycle in a prospective study. A generalized estimating equation approach adjusts for the dependency among outcomes within individual couples. The method can be applied in any setting where dependency among Bernoulli trials is induced by a susceptibility factor and the trial outcomes are only observable in the aggregate.

Algorithms↗