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Biomedical subjects

L Ornstein

Publications and source records attributed to L Ornstein.

At least 19 recordsLinked to original sources
PubMed1998

Nucleolar localization of BRCA1 protein in human breast cancer.

Both a rabbit polyclonal BRCA1 antibody, K-18, and a mouse monoclonal BRCA1 antibody, AP 16, produced nucleolar epithelial cell staining on frozen tissue sections of human infiltrating mammary carcinomas. There was much less BRCA1 antibody staining in normal tissues; however, 2 intraductal tumors and a papilloma, found in proximity to the carcinomas showed considerable nucleolar immunoreactivity. MCF-7 cells fixed in methanol and immunostained with the same two antibodies also revealed nucleolar staining, however, after 4% paraformaldehyde fixation for three minutes, there were many fewer nuclei stained. Antigen retrieval methods on formalin-fixed, paraffin-embedded specimens produced tumor cell cytoplasmic staining with AP 16 and nuclear staining in both tumor and normal epithelial cells with another BRCA1 monoclonal antibody, SG 11.

Adult↗
PubMed1992

c-myc protein distribution. Neoplastic tissues of the human colon.

There is an extensive literature documenting the increased or deregulated expression of the c-myc oncogene in human malignancies. The authors have recently devised a sensitive immunocytochemical method for studying the tissue localization of c-myc protein in tissue sections of human colon. We have compared nuclear c-myc staining using a polyclonal rabbit anti-c-myc antibody and a mouse monoclonal myc antibody NCM II 274. Microscopic observation of the tissue specific pattern of c-myc protein distribution shows that nuclear staining intensity varies in normal and neoplastic crypt cell nuclei in parallel with morphologic criteria of neoplasia. These studies yield further information on the usefulness of c-myc protein as a prognostic indicator.

Cell Nucleus↗
PubMed1988

Distribution of the c-myc oncoprotein in normal and neoplastic tissues of the rat colon.

A rat model of 5-azoxymethane induced colon cancer was studied in order to correlate histopathological changes and the differential distribution of the c-myc protein. Weanling Fisher 344 rats were injected with three, one week apart, subcutaneous injections of 5-azoxymethane (AOM) (15 mg kg-1) and the animals were divided into low and high fat diet groups. Nine colon tumors, of varying degrees of malignancy, that developed in the AOM-treated rats, and sections of normal colonic mucosa were examined. A rabbit polyclonal anti-c-myc antibody produced nuclear staining at 1:100 dilution in cryostat frozen sections of the normal rat colonic mucosa and the colon tumors when prepared with a Cryostat Frozen Sectioning Aid (CFSA). The tissue localization of the c-myc antibody staining revealed: (1) in normal mucosa, nuclei of the basal portion of the mucosa; (2) in adenomatous polyps, nuclei at all levels of the mucosa; and (3) in a carcinoma in situ, intense staining of glandular epithelial cell nuclei at all levels within the tumor. This procedure may provide a sensitive method for detecting abnormal cells in the colonic epithelium that have an altered proliferative capacity.

Animals↗
PubMed1985

Subtyping lymphocytes in peripheral blood by immunoperoxidase labeling and light scatter/absorption flow cytometry.

Lymphocyte subpopulations in a whole-blood sample can be detected by adapting mouse monoclonal antibodies (MAbs) and peroxidase (EC 1.11.1.7) labeling to a flow cytometer equipped with a tungsten-halogen light source and scatter/absorption optics (Technicon H6000). In the optimized cytochemical conditions each cell population generates a distinct, well-separated cluster, for accurate "thresholding" of the surface-antigen negative and positive lymphocyte populations in the presence of other leukocytes. After reaction with MAb, the erythrocytes are lysed, and the lymphocytes and other leukocytes are fixed. Biotinylated anti-mouse IgG, used as a bridge, amplifies the response from the avidin-peroxidase label. Granulocytes and monocytes, which have high endogenous peroxidase activity, and the labeled lymphocytes are stained in a specific amount of hydrogen peroxide plus 4-chloro-1-naphthol in 4-(2-hydroxyethyl)-1-piperazine-ethanesulfonic acid buffer. Accuracy and precision are equivalent to those of flow cytometers that measure immunofluorescence (e.g., Ortho Spectrum III), as demonstrated with OKT3, OKT4, OKT8, OKT11, and Leu 12 MAbs.

Adult↗
PubMed1981

Fully automated preparation of high-quality stained blood films.

A detailed description is given of the operation of Technicon's AutoSlide, which automatically produces a microscope-ready, precipitate-free, stained blood smear with superior cell distribution and good morphology. A 40-test-tube turntable carrying anticoagulated blood inputs samples at 40-second intervals. The blood films are drawn consecutively on a continuous Mylar substrate, with nylon mesh replacing the usual glass slide spreaders. This flexible substrate then passes through drying, fixing, staining and final drying stations. The methanol of conventional Romanowsky stains is replaced by low-volatility solvents. The fixing solution contains solvents, toluidine blue O, glutaraldehyde and a trace of water. The modified Giemsa-stain stock, when mixed with buffer, remains precipitate free for several days. Finally the blood film is imprinted with a date and identification number. Liquid monomer is dispensed onto each stained blood film, followed by a microscope slide. The monomer is then polymerized using ultraviolet light. Permanent transfer of the stained and labeled blood film occurs when the Mylar is stripped from the slide. The usable area for examination is approximately five times larger than that of a typical manual wedge smear.

Blood Cells↗
PubMed1976

Automatic leukocyte classification using cytochemically stained smears.

A leukocyte classification algorithm suitable for automated differential counting has been developed for blood smears stained with a new three-component cytochemical stain which has relatively narrow absorption bands centered at 460, 540 and 640 nm, respectively. The classification procedure is the result of a pattern recognition experiment using a sample of 223 leukocytes distributed evenly over the five normal cell types. The basic data for each cell were three digital microscopic images obtained with narrow band illumination at the above central wavelengths using a TV-digitizer system interfaced to a PDP-15 computer. The classification algorithm involves a sequential decision procedure utilizing five pattern features computed from the intensity histograms of the green and blue digital images. Thus the number of arithmetic operations and the number of computer memory words necessary to perform the classification into one of the five normal white blood cell types are both proportional to n where n is the number of gray levels into which the intensity scale is divided. In this experiment, n equals 256. Comparison of our results with work of others on smears prepared with Romanowski-type stains indicates that such narrow-band, spectrally well separated cytochemical multiple stains can permit the use of algorithms which are approximately ten times faster.

Autoanalysis↗
PubMed1975

C3, GBG, orosomucoid and haptoglobin polymorphisms. Improved staining methods.

C3, GBG, and orosomucoid polymorphisms were electrophoresed in a high-voltage agarose method which permitted the typing of 15-20 samples. The increased sensitivity of the dye Coommassie blue was used to stain the protein, and yielded higher resolution than amido black. The typing of haptoglobin samples, was facilitated by devising a method which utilizes the peroxidase activity of the haptoglobin-hemoglobin complex with 90-tolidine and hydrogen peroxide as substrates and 4-chloro-1-naphthol as coupler.

Complement System Proteins↗
PubMed1975

Basophil counting with a new staining method using alcian blue.

Difficulties in obtaining reproducible and accurate enumeration of circulating basophils with existing techniques have hampered investigation of this infrequent cell population. A new basophil staining method is described that employs alcian blue dye for staining of heparin within basophils at low pH and in the presence of lanthanum ions. Basophil recognition is facilitated by reducing nonspecific nuclear staining. This objective is achieved because of the differences in stability of alcian blue-heparin, alcian blue-nucleic acid, lanthanum-heparin, and lanthanum-mucliec acid complexes. Reduction of pH after staining also favors solubilization of leukocyte cytoplasmic proteins, providing greater contrast between stained and unstained cells by reducing light scattering of the unstained leukocytes . The alcian blue staining method is suitable both for chamber basophil counting and automated basophil counting using continuous-flow sampling and electro-optical detection. The new staining method was evaluated by comparing it with the chamber counting method using toluidine blue in a triple-blind study in which the results of basophil counting by the alcian blue chamber method, alcian blue automated instrument method, and the toluidine blue chamber method were analyzed for reproducibility and compared with an indirect basophil count obtained from a 1000-cell leukocyte differential and a total leukocyte count. Both alcian blue staining methods gave greater reporducibility that toluidine blue and were more accurate, as evidinced by a significantly higher correlation with the indirect basophil count. The improved reproducibility, accuracy, and convenience of this method over existing methods should facilitate the collection of more meaningful information about circulating basophil levels in health and disease.

Alcian Blue↗
PubMed1970

The intrarenal distribution of tritiated para-aminohippuric acid determined by a modified technique of section freeze-dry radioautography.

Section freeze-dry radioautography has been used to examine the intrarenal distribution of a water-soluble organic acid (para-aminohippuric acid (PAH-3H)) under constant-infusion, steady-state conditions in mouse and rat kidney in vivo. The technique described here has the following advantages: (a) Sectioning and freeze-drying are accomplished in a closed cryostat at temperatures below -40 degrees C; (b) Handling of the section is facilitated by mounting of the section-to-be on adhesive-coated Saran Wrap prior to cutting; (c) Unembedded freeze-dried sections are attached to photographic film at ambient temperature in the dark room; (d) Fixation follows completion of radioautographic exposure and precedes photographic development; (e) Permanent close contact is maintained between tissue and film. Morphologic preservation compared favorably with that obtained by optimal fixation techniques, which, however, permit diffusion. Cellular accumulation of PAH-3H during secretion was demonstrated in the proximal tubule under steady-state conditions in vivo. The cellular concentration of PAH-3H was uniform throughout the length of the proximal tubule in mouse and rat kidney.

Aminohippuric Acids↗