Biomedical subjects

E Bartfeld

Publications and source records attributed to E Bartfeld.

7 recordsLinked to original sources

PubMed1992

Relationships between orientation-preference pinwheels, cytochrome oxidase blobs, and ocular-dominance columns in primate striate cortex.

The relationships between cytochrome oxidase blobs, ocular-dominance columns, and iso-orientation domains, subsystems underlying visual perception, were explored in primary visual cortex of macaque monkey. High-resolution maps of these three subsystems were acquired. Optical imaging based on activity-dependent intrinsic signals revealed that the most prominent organizational feature of orientation preference was a radial arrangement, forming a pinwheel-like structure surrounding a singularity point. More than 80% of these pinwheels were centered along the midline of ocular-dominance columns. The iso-orientation contours of adjacent pinwheels crossed borders of ocular-dominance columns at approximately right angles. Pinwheels with the same or opposite directions of orientation-preference change were smoothly connected with each other. On the average, all orientations were equally represented. In exactly the same cortical area, the cytochrome oxidase blobs, thought to be involved in color processing, were also mapped, using cytochrome oxidase histology. Like the centers of pinwheels, the centers of blobs also lie along the midline of ocular-dominance columns. However, the centers of pinwheels did not coincide with the centers of blobs; these two subsystems are spatially independent. "Hypercolumn" modules, each including two complete pinwheels in two adjacent columns of complementary ocularity, as well as portions of a few blobs, were frequently found but did not seem to be the primary unit of cortical organization. An alternative to hypercolumns is proposed.

Animals↗

PubMed1991

High-resolution optical imaging of functional brain architecture in the awake monkey.

Optical imaging of the functional architecture of cortex, based on intrinsic signals, is a useful tool for the study of the development, organization, and function of the living mammalian brain. This relatively noninvasive technique is based on small activity-dependent changes of the optical properties of cortex. Thus far, functional imaging has been performed only on anesthetized animals. Here we establish that this technique is also suitable for exploring the brain of awake behaving primates. We designed a chronic sealed chamber and mounted it on the skull of a cynomolgus monkey (Macaca fascicularis) over the primary visual cortex to permit imaging through a transparent glass window. Restriction of head position alone was sufficient to eliminate movement noise in awake monkey imaging experiments. High-resolution imaging of the ocular dominance columns and the cytochrome oxidase blobs was achieved simply by taking pictures of the exposed cortex when the awake monkey was viewing video movies alternatively with each eye. Furthermore, the functional maps could be obtained without synchronization of the data acquisition to the animal's respiration and the electrocardiogram. The wavelength dependency and time course of the intrinsic signal were similar in anesthetized and awake monkeys, indicating that the signal sources were the same. We therefore conclude that optical imaging is well suited for exploring functional organization related to higher cognitive brain functions of the primate as well as providing a diagnostic tool for delineating functional cortical borders and assessing proper functions of human patients during neurosurgery.

Animals↗

PubMed1989

A double staining method for measuring DNA content of specific cell populations utilizing computerized microscopy.

A method for identifying specific cell populations with the computerized microscope is described. This method utilizes double staining techniques using immunofluorescent antibodies and the Feulgen technique. It was applied to measure the area and DNA content of the nuclei of beta-cells in patients with Persistent Neonatal Hypoglycemia with Hyperinsulinism (PNHH). A significant increase in the area and DNA content was found in nuclei of patients compared to a control group. This method may be applied to sample cells from other tissues as well.

Coloring Agents↗

PubMed1989

The streaming liver IV: DNA content of the hepatocyte increases with its age.

Hepatocyte age was estimated from its distance from the portal tract. We have previously shown that hepatocytes are formed adjacent to the portal tract and stream toward the terminal hepatic vein, advancing at a daily velocity of 2 microns. Thus, the farther a cell from the portal tract, the older it is. This relationship between cell age and distance served here for the study of age-dependent changes in the hepatocyte, particularly nuclear area and DNA content. DNA content was derived from the absorbance of Feulgen-stained nuclei in 5-microns-thick tissue sections. Absorbance and nuclear area were measured with a cytophotometer. Since most nuclei of the tissue section were sliced, DNA content was estimated also in intact nuclei which were sampled by fine needle aspiration, and stained with either Feulgen or propidium iodide. Feulgen-stained nuclei were scanned by a cytophotometer, while the DNA content of propidium iodide-stained nuclei was measured by flow cytometry. Absorbance was expressed in relationship to the mean absorbance of diploid periportal littoral cells. Littoral absorbance was defined as one absorbance unit. A high correlation between nuclear absorbance and area was observed in nuclear suspensions (adjusted r-square 0.79), so that nuclear area may serve as a good predictor of nuclear DNA content, which is valuable in routine sections which are stained with H and E. Most periportal hepatocytes were polyploid and their mean absorbance was 1.68 units. Nuclear absorbance increased with cell distance from the portal tract. Within 100 microns it rose from 1.68 to 1.92 units. Nuclear area increased by 13%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

The streaming liver. V: Time and age-dependent changes of hepatocyte DNA content, following partial hepatectomy.

Two processes contribute to the change in hepatocyte ploidy following partial hepatectomy: one is age-dependent, while the other depends on the time which has elapsed since hepatectomy. While in the normal liver hepatocyte DNA content increases with the age of the cell, following hepatectomy the average DNA content (or ploidy) for the entire population rises as well. Hepatocyte age was derived from the cell's distance from the portal tract. We have previously shown that hepatocytes are formed adjacent to the portal tract and stream toward the terminal hepatic vein, advancing 2 microns/day. This finding enables the estimation of hepatocyte age from its location, since the older a cell the more remote it is from the portal tract. Twenty-four young male random-bred rats were partially hepatectomized and killed in groups of four animals at the following times: 1 h and 1, 2, 3, 7 and 14 days. Liver sections and nuclear suspensions which were collected by fine needle aspiration were stained with Feulgen and measured with the aid of computerized image cytometry. Part of the suspension which was aspirated with a fine needle was stained with propidium iodide and measured by flow cytometry. Both nuclear area and the DNA content increase with the age of the cell. The older a cell, the higher its ploidy. Generally, young hepatocytes which synthesized DNA did also divide, while older cells tended to accumulate DNA and became polyploid. The average nuclear DNA content of the entire population increased by 14% in 3 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Nesidiodysplasia--a histologic entity?

Five cases of persistent neonatal hyperinsulinemic hypoglycemia (PNHH) were studied by a combined immunofluorescent and Feulgen technique under a computerized microscope which was used to measure the area and absorbance of beta cell nuclei. An increase of 16% was found in the nuclear area and absorbance of the beta cells in PNHH cases, in comparison with age-matched control cases. A smaller increase (9%) was found in nuclear area and absorbance of non-endocrine ductal cells in PNHH cases. In all PNHH and control cases, higher values of nuclear area and absorbance were found for beta cells in the islets of Langerhans than for nesidioblasts. The increase in average size of beta cell nuclei in PNHH can be used as a morphologic criterion for diagnosis in these cases. The increased absorbance of the nuclei stained with the Feulgen reaction is the morphologic expression of polyploidy, and has a correlation to the metabolic activity of beta cells in this disorder. We conclude that, in contrast to the normal postnatal developmental process of nesidioblastosis, nesidiodysplasia is a well-defined histologic entity, manifested by an increase of beta cell nuclear size and its DNA content.

Humans↗

PubMedDate not supplied

Cellular changes in the mammary gland epithelium during the menstrual cycle. A computer image analysis study.

While examining fine needle aspirates of lesions, it became evident that preovulatory aspirates differed from postovulatory ones. Proliferation activity was noted in cells and in fragments aspirated during the luteal phase. In order to verify this observation, pairs of smears obtained during different phases of the menstrual cycle from eight fertile women were studied by computer image analysis. Using discriminant analysis based on nuclear features extracted from the digitized cell images, 84.87% of all cells were correctly classified as preovulatory or postovulatory, according to the smear of origin. When the classification was restricted to only the cells from each woman, a 100% correct identification of cell types was obtained, which supports the visual observation that there are cellular changes in the mammary epithelium correlated to the menstrual cycle. Since some proliferative changes may mimic atypia or malignancy, these findings suggest that it is advisable to perform needle aspirations of breast lesions during the preovulatory phase of the cycle.

Adolescent↗