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PubMedDate not supplied

[Ecology of the ceratopogonids of the Alsace plain. II. Spatial distribution of Culicoides larvae in a fluvial breeding-place (author's transl)].

The conditions of larval life of Culicoides in a mud-bank near a river are studied. Pedological and physical characteristics are measured. The distribution of species in regard to the saturation rate is following: C. clastrieri : 45 to 100 % of saturation (max. : near 100 %), C odibilis : 85 to 100 % (max. : 97-99 %), C. cubitalis : 45 to 100 % (max. : 85 %), C musilator : 85 to 100 % (max. : 95 %), C. subfascipennis : 85 to 99 %, C. pumilus : 45 to 85 % (max. : 45 %).

Animals↗
PubMed1994

Spatial distribution of 3-hydroxy-3-methylglutaryl coenzyme A reductase messenger RNA in the ocular lens: relationship to cholesterologenesis.

This study probes the regulation of cholesterol biosynthesis in the ocular lens by estimating the concentration and distribution of the messenger RNA for the rate-controlling enzyme for sterol synthesis, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR). Because the lens is dependent on biosynthesis for cholesterol, HMGR activity is crucial for the life-long growth of this organ. Young rat lenses were serially divided into several fractions by dissolution in an SDS-containing buffer and each fraction was equated to a percent of the lens radius based upon its protein content. HMGR enzyme activity and cholesterol synthesis has been shown to disappear from the lens cortex over a narrow arc of radius due to loss of enzyme protein. Using a published competitive reverse transcriptase-polymerase chain reaction method for amplifying HMGR mRNA (Powell, E. E., and P. A. Kroon. 1992. J. Lipid Res. 33: 609-614), an average of about 46,000 copies of this mRNA was estimated per lens at all rat ages examined (5-day-old to adult). However, copies/microgram total RNA decreased with aging. The distribution of HMGR mRNA across 95-60% of the lens radius was essentially uniform at 2000-3000 copies/mm3 tissue. But the very superficial cortex contained 5- to 7-times this concentration and accounted for about 35% of the total copies/lens. We estimated that cells in this region each contained 1 to 2 copies of message, a value similar to the estimated copy number of HMGR message in human lymphocytes (Powell and Kroon, ibid). This suggests that the translational efficiency and stability of lens HMGR mRNA must be very high.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1994

Spatial distribution of DNA ploidy in colorectal carcinoma.

This paper reports on the phenomenon of heterogeneity of DNA distribution in colorectal carcinoma. The aim of this study was to find a new strategy in sampling methodology as a solution to the heterogeneity problem by studying ploidy topography. The study was carried out by using image analysis for densitometric measurements of tissue imprints of 19 colorectal specimens after Feulgen staining. Heterogeneity of ploidy in colorectal carcinoma is well known; therefore, we wished to determine whether this heterogeneity is random within different parts of a colorectal tumour. For each tumour, five systematic and reproducible samples were taken from the peripheral, intermediate and central tumoural areas. In addition two samples were taken from adjacent non-tumoural areas: one from the proximal and the other from the distal site with respect to the neoplastic lesion. By using image analysis three parameters were obtained. Mean DNA content was computed for each sample and expressed in arbitrary units (DNA-a.u.) from the measurement of integrated optical density according to the Beer Lambert law. Secondly mean DNA content expressed in relative units (DNA-r.u.) was computed according to an internal euploid control. Finally entropy was computed from each histogram of DNA content. Experimental design was based on a repeated measures analysis of variance with a priori orthogonal comparisons. We found that DNA content and particularly entropy are not randomly distributed. Furthermore, there was a significant difference between the two non-tumoural epithelia.

Colorectal Neoplasms↗
PubMed1994

Selected aspects of the population health status in ecological hazard areas in comparison with ecologically "clean" area. II. Assessment of spatial distribution of mortality.

On the basis of age adjusted rates of mortality from all diseases and from diseases of the circulatory system in female and male populations living in ecological hazard areas and in ecologically "clean" area, the distributions of the rate values were assessed. In the regions under consideration, urban and rural regions were distinguished. The goodness of fit of the empirical distribution to the normal one was assessed using the following statistical parameters: arithmetic mean, mode, median, standard deviation, coefficient of variation, coefficient of asymmetry, difference between the third and the first quartiles, as well as the Chi2 and lambda-Kolmogorow-Smirnow tests, maximum difference between cumulative distribution functions and standard deviation of differences between empirical and theoretical frequencies. A differentiation in the mean values of age adjusted rates of mortality from both groups of diseases in ecological hazard areas and in "clean" area was indicated particularly in urban female and male populations.

Cardiovascular Diseases↗
PubMed1995

Diminutive colonic polyps: histopathology, spatial distribution, concomitant significant lesions, and treatment complications.

OBJECTIVES: Our objectives in this study were to determine diminutive colonic polyp histology, distribution, frequency of significant synchronous neoplastic lesions, and treatment complications. METHODS: We evaluated consecutive colonoscopic examinations in which one or more diminutive polyps were detected over a 36-month period; these examinations had been entered into an endoscopy database at the time of colonoscopy. RESULTS: A total of 1964 diminutive polyps were found and removed in 753 colonoscopies; 1525 were removed by hot biopsy, 436 were removed by cold biopsy, and three were removed by snare. Of the diminutive polyps, 40.7% were adenomatous, 37.2% were hyperplastic, 17.9% were mucosal tags or lymphoid aggregates, and 4.3% were mixed; 0.26% contained atypia, and none were cancerous. In the right colon and transverse colon, diminutive polyps were more likely to be neoplastic (p < 0.0001), but in the left colon they were more likely to be nonneoplastic (p < 0.0001). The prevalence of synchronous neoplastic lesions was 21.5%. No perforations were seen; however, significant hemorrhages occurred in six cases in which hot biopsy was used. The risk of a significant hemorrhage from hot biopsy of diminutive polyps was 0.39%. The risk of hot biopsy-induced hemorrhage was significantly higher in the right colon than in the transverse colon and left colon (p < 0.05). The risk in the cecum was 1.33%; in the ascending colon it was 1.03%, and for the remainder of the colon it was 0.24%. CONCLUSIONS: Most diminutive polyps proximal to the left colon are neoplastic. The decision to use the hot biopsy or cold biopsy technique to eradicate diminutive polyps should take into account the location of the polyp because of the significantly increased risk of hemorrhage with hot biopsies in the right colon.

Adenoma↗
PubMed1993

Spatial distribution of viable cells immobilized in agar membranes.

The biocatalytic structures obtained by immobilizing microorganisms in planar gel slabs have been studied and modeled to better understand the dynamics of systems controlled by diffusion-reaction-growth couplings. The theoretical results give two kinds of information: the time evolution of the extra-membrane system due to the intra-membrane reactions which can easily be compared to experiments, and the intra-membrane behaviour which is mainly characterized by the concentration profiles. The steady state cell concentration profile is one of the most important elements of a system's behaviour. In addition to photographs taken at different depths in the membrane, we have developed an original, simple and reproducible technique for the experimental determination of the intra-membrane cell concentration profiles. The technique uses a home-made microtome to obtain gel slices, in which the cell concentration is determined using visible spectroscopy. By using this technique, we have shown a good agreement between the theoretical predictions and the experimental profiles, which validates the modeling.

Agar↗
PubMedDate not supplied

[A transesophageal color-coded pulsed Doppler echocardiographic study of the spatial distribution of mitral regurgitation jets].

OBJECTIVE: Transesophageal echocardiographic analysis of color Doppler characteristics of mitral valvular regurgitation jets. DESIGN: Transesophageal echocardiographic prospective study. SETTING: Ambulatory patients referred to Echocardiographic Laboratory of Gregorio Marañon General Hospital, Madrid, Spain. MATERIAL AND METHODS: We studied a group of 100 consecutive patients with mitral regurgitation diagnosis. In each patient we calculated the degree of severity, percentage of wall intersection, maximal traced area, axis direction, atrial depth, maximal transversal diameter, perimeter and angle of the mitral regurgitation jet. We divided the entire population in three different groups according to the jet direction in central (CJ), eccentric (EJ) and wall jets (WJ). MAIN RESULTS: The direction of the mitral regurgitation jet was central in 49%, eccentric in 33% and impinging the left atrial wall in 18%. The mitral regurgitation jet angle was in the CJ 80 +/- 11 degrees, EJ 33 +/- 10 degrees and WJ 6 +/- 7 degrees. Maximal mitral regurgitant traced area in CJ was 732 +/- 104 mm2, EJ was 593 +/- 110 mm2 and WJ was 267 +/- 80 mm2. Maximal regurgitant jet depth in CJ was 36 +/- 17 mm, EJ 30 +/- 15 mm and WJ 49 +/- 14 mm. The perimeter of the mitral regurgitation jet in the CJ was 87 +/- 22 mm, EJ was 68 +/- 22 mm and WJ was 92 +/- 30 mm. CONCLUSIONS: Color Doppler quantification criteria are not useful in all patients with mitral regurgitation jets. The presence of atrial walls close to the mitral regurgitation jet area is an important factor in the mitral regurgitation color Doppler evaluation.

Adult↗
PubMed1996

Mouse molar morphogenesis revisited by three-dimensional reconstruction. II. Spatial distribution of mitoses and apoptosis in cap to bell staged first and second upper molar teeth.

Tooth morphogenesis is a complex multifactorial process in which differential mitotic activities and cell death play important roles. Upper first (m1) and second (m2) molars from mouse embryos were investigated from early cap to bell stage. m2 differed from m1 by delayed origin of the enamel grooves delimiting the protrusion of the cap bottom towards the dental papilla, and retardation of the enamel knot formation. The width of the m2 enamel organ was conspicuously smaller during cap formation and length remained smaller throughout the period of observation. Formation of the cap depression was comparable in m1 and m2, however margins delimiting the enamel organ cavity arose in m1 and m2 as mirror images. Attempts were made to correlate changes in the distribution of apoptotic cells and bodies and/or mitoses with morphogenesis. These cellular activities were recorded from histological sections and represented in space using computer-assisted three-dimensional reconstructions. Mitoses in the epithelial compartment were associated with the development of the cervical loop. In the mesenchyme of m1 at early bell stage, a postero-anterior increasing gradient of mitoses was observed which might be correlated with the anterior growth of the molar. Cells in the enamel knot demonstrated a high level of apoptosis, retarded in m2, but absolutely no division. Apoptotic processes were also involved in the anterior delimitation of the m1 epithelium. Apoptosis might correspond to the programmed destruction of cells whose function had to be suppressed or whose potential activity had to be avoided.

Animals↗
PubMed1996

[Spatial distribution of facial volumes. Ontogenetic and phylogenetic study with vestibular orientation].

On cephalic skeleton of Man and two species of chimpanzees, statistically considered during their growing, a sagittal area is measured in facial mass and total face. Barycenters are determined. This points describe, in vestibular axis, ontogenic curves with posterior concavity more important in Man. Remarkable relations exist between barycenters and several facial and mandibular points, and with those of frontal and parietal vault.

Adolescent↗
PubMed1996

[Investigation on spatial distribution of chloronaphthalenes in flounder Platychtis flesus from the gulf of Gdansk].

Flounders from the three different and relatively distant sites in the Gulf of Gdańsk were collected in august and october 1992 and analysed to investigate a potential differences in concentration and composition of chloronaphthalenes. The method of PCNs measurement was capillary gas chromatography and high resolution mass spectrometry (HRGC/HRMS) after a nondestructive extraction and cleanup step via dialysis with polyethylene membrane and than HPLC preseparation on a activated carbon column. Chloronaphthalenes were separated and quantified on RTx-5 capillary column using an electron impact (EI) mode and selective ion recording (SIR). All samples contained detectable concentrations of many tetra-, penta- and heksachloronaphthalenes, and the total PCNs concentration ranged from 1700 to 3900 pg/gwet weight. A substantial difference in pattern and concentration of PCNs residues in flounders between some of the sampling sites were found.

Animals↗
PubMed1997

Mouse molar morphogenesis revisited by three-dimensional reconstruction. III. Spatial distribution of mitoses and apoptoses up to bell-staged first lower molar teeth.

Computer-assisted 3D reconstructions were used to follow the development of the embryonic mouse first lower molar (M1). At ED 12.5, the thickening of the oral epithelium, which was thought to correspond to the molar dental lamina, regressed in its anterior part as a result of apoptosis. Only the posterior part later gave rise to molars. The transition to the cap stage entailed medial and lateral extensions of the dental epithelium. The growth and histo-morphogenesis of the enamel organ as well as cervical loop formation proceeded more rapidly in the anterior part of the M1 during the cap and early bell stages producing significant morphological differences along the antero-posterior axis. Apoptosis was temporarily intensive in the anterior part of the bud- and cap-shaped epithelium and thus pointed domains which do not participate in the formation of the final M1 enamel organ. In the well-formed cap, apoptoses displayed maximum concentration in the enamel knot (EK). No increase in the number of metaphases could be detected in the vicinity of the EK. Mitoses were distributed throughout the epithelial compartment until cap stage and then mainly concentrated in the inner dental epithelium at the early bell stage. At this later stage, either lateral views or thick virtual sections performed in the reconstruction demonstrated a clear cut distribution of mitoses and apoptoses in the enamel organ. At the early bell stage, mitoses in the mesenchyme demonstrated an increasing postero-anterior gradient.

Animals↗
PubMed1997

Spatial distribution and seasonality of ticks (Acarina: Ixodidae) in a protected area in the northern Apennines.

Infestation of small rodents by ixodid ticks and frequency of host-seeking ticks collected by dragging were studied at Orecchiella Natural Park (Northern Apennines) in 1994 and 1995. Levels of infestation of Apodemus spp. by immature Dermacentor marginatus were higher in beech wood (5.1 larvae and 1.3 nymphs per mouse) than in oak-chestnut wood and in coniferous wood. Larval D. marginatus peaked in mid summer, whereas nymphs peaked in late summer. Host-seeking Haemaphysalis punctata were mostly found on south-facing limestone rocks with scarce vegetation (7.8 larvae/km dragging). Conversely, D. marginatus larvae were most frequent in wooded areas (3.2 larvae/km dragging). Ixodes ricinus was rare in the Park, and Borrelia burgdorferi was not isolated from ear punches collected from 122 small rodents.

Animals↗
PubMed1998

Temporal and spatial distribution of DNA topoisomerase II alters during proliferation, differentiation, and apoptosis in HL-60 cells.

We related cellular content of DNA topoisomerase (topo) IIalpha and IIbeta with the cell cycle position in proliferating, differentiated, and apoptotic HL-60 cells using two-dimensional flow cytometry. In logarithmically growing HL-60 cells, topo IIalpha increased especially in late S to G2/M phases, although the topo IIbeta level was almost constant throughout the cell cycle. Induction of differentiation by all-trans retinoic acid dramatically reduced the topo IIalpha but not the topo IIbeta level. A new G2/M population containing virtually no topo IIalpha appeared during differentiation and was supposed to be alive and noncycling. Two-dimensional flow cytometry of topo IIalpha or IIbeta staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling assay showed that one topo IIbeta epitope situated at the C-terminal end decreased specifically in apoptotic HL-60 cells treated with Ara-C, etoposide, and vincristine. The amounts of a topo IIalpha epitope and another topo IIbeta epitope located at a more central portion were almost equal between apoptotic and nonapoptotic cells. Western blot analysis confirmed that topo IIbeta protein was completely degraded into smaller fragments and lost its C-terminal end during apoptosis. On the contrary, a large portion of topo IIalpha remained of its original size, although both topo IIalpha and IIbeta left from the nuclear fraction in apoptotic cells. Confocal laser microscopy showed nuclear localization of topo IIalpha and IIbeta in growing HL-60 cells. Although topo IIalpha and IIbeta were distributed throughout the cell during mitosis, only topo IIalpha was densely concentrated in the mitotic chromosomes. Both enzymes were dissociated from the genomic DNA even at an early phase of apoptosis and completely separated from the propidium iodide signal of DNA in the advanced stage. Chromatin condensation process in apoptosis is therefore completely topo II-independent and obviously differs from the mitotic one.

Apoptosis↗