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PubMedDate not supplied

Data regarding the structural feature of nervous elements in the bile ducts during intrauterine life.

The nervous elements of the extrahepatic bile ducts were studied on serial sections prepared from rabbit and human embryos and foetuses, using silver impregnation techniques. In the gallbladder of rabbit embryos and foetuses, the nervous elements are absent, whereas the bile ducts possess a dense parasympathetic vegetative plexus. In human embryos, the muscular layers and submucosa of the gallbladder and bile ducts have well developed parasympathetic plexuses and a sympathetic subserous plexus, without nerve cells, respectively. The histotopical identification of nervous elements in the bile ducts allows the distinction of parasympathetic plexuses from the sympathetic ones.

Adrenergic Fibers↗
PubMed2004

Lessons from MPO deficiency about functionally important structural features.

Genetic abnormalities often serve as the catalyst to stimulate critical insights into normal biology. In many cases, examining such experiments of Nature explicates not only the abnormal but also serves to illustrate underlying normal principles. Within the context of myeloperoxidase biosynthesis, we have examined the impact of specific missense mutations that cause inherited myeloperoxidase deficiency. Such studies have provided novel insights not otherwise possible. We have described three such mutations and are completing the analysis of a fourth.

Humans↗
PubMedDate not supplied

[Computed tomography in the evaluation of cochlear structural features in cochlear implantation].

Temporal bone computed tomographic scans were studied in 136 deaf patients of different age and sex, including 56 patients (39 children and 17 adults) rehabilitated with cochlear implantation (CI). The mean values of the cochlear parameters that are important for the results of a surgical CI stage, namely: the diameter of the cochlear base (DCB), the diameter of the basal helix, the height of the cochlea, the angle between the cochlear base and the promontorial wall, were calculated. These parameters were compared in different age groups. A correlation was determined for each of the studied parameters and for the depth of intracochlear insertion of electrodes. There was a significant correlation between DCB and the depth of insertion of the electrodes of CI22M and CI24M cochlear implants. DBC at which the active part of the electrode chain of an implant could be significantly more frequently placed in the tympanic scala of the cochlea was estimated.

Adolescent↗
PubMed2005

[Structural features of the heart coronary sinus in adult humans].

The aim of investigation was to study the morphologic features and morphometric parameters of coronary sinus of the human heart with special reference to age- and gender-dependent differences. 330 hearts of male and female patients, who died at the age of 21-92 years from different reasons, were in studied. The length and width of coronary sinus and its main shape characteristics were analyzed. 57 histological specimens were stained with hematoxylin-eosin, using van-Gieson's and Hart's method. The coronary sinus tunics were described and their thickness was measured. As the result of this study, it was found that both length and width of coronary sinus at the point of its entrance into the right atrium were dependent on the gender of the patients and were larger in males. The width of coronary sinus increased with age in the patients with diseases characterized by predominant loading of the left ventricle. In these patients, conical shape of coronary sinus was present in all the ages. In humans with no diseases of cardiovascular system, the shape of coronary sinus was shown to change with age from cylindrical to conical. The thickness of tunics forming the walls of coronary sinus in this group was independent on gender and age.

Adult↗
PubMed1991

Common structural features among monoclonal antibodies binding the same antigenic region of cytochrome c.

To examine if there are common physicochemical features among antibodies binding the same antigenic region of a protein, B cell hybridomas were prepared against the two major antigenic regions on mammalian cytochromes c, and the nucleotide sequences encoding the monoclonal antibody (mAb) heavy (H) and light (L) chains were determined and compared. Although the genetic elements used were somewhat diverse, similarities among mAbs to a given antigenic region were observed. In particular, mAbs binding in a region situated at a bend in the antigen around residues 44 and 47 had longer complementarity-determining regions (4-5 additional amino acid residues in L1 and 1-2 in H3) than mAbs binding the other region around residues 60 and 62 located on a relatively flat surface. These observations indicate that the topography of an antigenic site and the lengths of certain complementarity-determining regions are important physicochemical properties determining, at least in part, which antibodies (B cells) will participate in an immune response to a particular site on a protein antigen.

Amino Acid Sequence↗
PubMed1991

Organizational components and structural features of EPA's new Human Exposure Research Program.

Modern technology has brought about a dramatic increase in the production and consumption of man-made chemicals and in their resulting emissions. It is clear that these emissions and their by-products will likely affect our environment and have a health impact on the population exposed to them. Knowledge of exposure is required to document the impact of these emissions on human health. However, measuring, interpreting, and characterizing human exposures are extraordinarily complex processes because exposures may occur by multiple routes, multiple sources, and they are subject to a wide range of temporal, spatial, and source variations often from both anthropogenic and non-anthropogenic sources. The Environmental Protection Agency's approach to exposure research has often been insufficient to understand and mitigate these complex real-word exposures. For example, we do not know the population exposure distributions of most pollutants and the relative contributions of sources to these distributions. Without this knowledge as input into EPA's risk management process, EPA's may not be making the most effective environmental management decisions for reducing human health risks. The Human Exposure Research Program is a direct response to this need to understand how and to what extent humans are exposed to environmental pollutants.

Databases, Factual↗
PubMed1991

[Systemic reorganization of the architechtonics of polytene chromosomes in onto- and phylogenesis of malaria mosquitoes. Structural features regional of chromosomal adhesion to the nuclear membrane].

Principles of organization of chromocenter in salivary gland cells and zones of chromosome attachment to nuclear envelope in ovarian nurse cells were determined. It was shown that blocks of centromeric heterochromatin (alfa-heterochromatin) have no direct connection with nuclear envelope. Such connections are ensured by beta-heterochromatin. Homologous chromosome regions were shown to be of different morphology and nature of chromosome-membrane links in different mosquito species. A map of polytene chromosomes of ovarian nurse cells in Anopheles messeae Fall, was established. No differences were found in band quantity of these chromosomes as compared to salivary gland chromosomes.

Animals↗