Biomedical subjects

D J Zahniser

Publications and source records attributed to D J Zahniser.

33 records · Page 2Linked to original sources

PubMed1986

Sexual dimorphism in the preoptic/anterior hypothalamic area of ferrets: effects of adult exposure to sex steroids.

The organization of neuronal cell bodies in the caudal preoptic area (POA) and rostral anterior hypothalamic area (AH) was studied in Nissl-stained brain sections from adult male and female ferrets. Computer-assisted image-analysis procedures were developed to help estimate the areas of cellular density and the sizes of individual perikarya. At the junction of the POA and AH, a bilateral dorsal-medial group of neurons was apparent only in male ferrets (dorsal nucleus). At the same coronal level, a ventral-medial group of neurons was apparent bilaterally in both males and females (ventral nucleus). The mean somal area of cells in the dorsal nucleus of males was significantly greater than the mean somal area of cells in the corresponding dorsal region of females or in the ventral nucleus of both sexes. The dorsal nucleus was clearly discernible in adult males regardless of their hormonal status, although cells in the dorsal nucleus were larger in intact breeding males or gonadectomized males given testosterone, estradiol or dihydrotestosterone than in gonadectomized males given no gonadal hormones or given progesterone. Neither the grouping of large cells nor the steroid-induced increase in cell size, characteristic of the male dorsal nucleus, was seen in the comparable dorsal region of females. The sex difference in cellular organization observed in the ferret at the junction of the POA and AH is the first difference of this type to be seen in the POA/AH of a non-rodent mammalian species. Its identification will, hopefully, aid in the analysis of the neural mechanisms that control various sex-specific behaviors in this species.

Animals↗

PubMed1986

Cytopress: automated slide preparation of cytologic material from suspension.

This paper describes a new automated system to prepare slides of cytological material from suspension. The system collects material on a filter tape by filtration and transfers it to glass slides by means of pressure-fixation. Using cervical cells as a model, results show that a well-defined cell number is evenly deposited over a standardized area, while a small number of cells is retained on the tape and a negligible number lost in the filtrate. Contamination is very small. Application of the system to other cytological material (fine needle aspirations, monolayer and cell suspension cultures, agar cultures, and isolated nuclei) is shown. In general, more than one slide can be made from one sample. Several histological staining procedures as well as immunofluorescence labeling protocols can be applied to the preparations obtained in this way. This system thus introduces a method that will standardize specimen preparation, is quick, saves operator time, and can be used for both diagnostic and research applications.

Autoanalysis↗

PubMed1986

Spectral bandwidth in automated leukocyte classification.

Investigators have repeatedly pointed out the importance of spectral information in the automated classification of white blood cells. In general, monochromatic images recorded through two or three color filters are used to extract this information. Although it has generally been thought that the use of narrow band filters provides "cleaner" color information than is obtainable through wide band filters, the choice has not been fully investigated and the question is far from being settled. The use of wide band filters has the clear practical advantage of increased light levels at the detector, resulting in higher signal-to-noise ratio with less demand on light source design. In order to investigate this issue, a series of 681 leukocytes of the most frequently occurring types were digitized by the use of both narrow (10 nm) and wide (90 nm) band filters. Parameters were extracted independently from both sets of images. These parameters were then used to develop a classifier for each set of images. The choice of features and classifier results indicate that there are no major performance differences between the two types of filters.

Cytological Techniques↗

PubMed1986

Differentiation in male ferrets of a sexually dimorphic nucleus of the preoptic/anterior hypothalamic area requires prenatal estrogen.

Experiments were conducted to determine when during perinatal development testicular steroids act in ferrets to promote the organization of a bilateral nucleus in a medial position at the border of the preoptic area (POA) and anterior hypothalamus (AH), henceforth referred to as the male nucleus of the POA/AH (MN-POA/AH). The formation of the MN-POA/AH was promoted in female offspring by treating their mothers with testosterone over the last 11 days of the 42-day gestation period, whereas MN-POA/AH formation was not disrupted in males castrated within 1, 2 or 5 days of birth. Additional experiments were conducted to determine whether the active hormone which induces differentiation of the MN-POA/AH in the male ferret is an androgen or an estrogen. MN-POA/AH formation was inhibited in males deprived prenatally of estrogenic stimulation via maternal ovariectomy and subcutaneous implantation of the aromatase inhibitor 1,4,6-androstatriene-3,17-dione (ATD) on gestational day 30. By contrast, MN-POA/AH formation was not disrupted in males exposed prenatally to the antiandrogen flutamide. These results imply that estrogen, derived from the neural aromatization of circulating testosterone, acts prenatally to promote the organization of the MN-POA/AH in male ferrets. The development of sex-dependent features of forebrain morphology may depend on the neural action of estrogen in males of diverse mammalian species.

Androstatrienes↗

PubMed1986

Automated deposition of cellular material on glass slides: Cytopress.

The present paper describes an automated apparatus called Cytopress that collects cells or cellular material e.g. nuclei out of suspension on a membrane film by filtration. In a second step this material is transferred on to a glass slide by means of standardized pressure-fixation. Thus slides of high quality are made rapidly and easily that are suited for a variety of stainings.

Adenocarcinoma↗

PubMed1984

A new disaggregation device for cytology specimens.

A new means of disaggregating cytology specimens in suspension using an immersible rotor device is described. The new rotor is compared to an automated syringing apparatus using cervical samples. Similar results using both devices are obtained for both normal and abnormal specimens.

Cell Separation↗

PubMed1984

Pressure-fixation method of transferring cells from polycarbonate filters to glass slides.

A technique for the preparation of cytology slides is presented by which cells collected on a polycarbonate membrane filter are transferred to a slide by means of simultaneous pressure and fixation. Using cervical samples as a model, the influence of the filtration rate, filter pore size and duration of pressure application on cell recovery was analyzed. The present version of the preparation procedure uses manual techniques that define the operating characteristics of a fully automated procedure.

Cytological Techniques↗

PubMed1983

Detecting infection-related changes in peripheral blood smears with image analysis techniques.

High-resolution image analysis has the potential to flag subtle changes in white blood cell morphology that may indicate the presence of certain diseases. A study was made of the feasibility of identifying patients with hematologic bacterial infections (sepsis) using measurements on Wright-Giemsa-stained peripheral blood smears. Neutrophils and lymphocytes from a group of patients with sepsis and from a control group were digitized, and parameters quantifying geometry, color, texture and shape were extracted. While color parameters differed the most between the infected and control samples, substantial differences in geometric, texture and shape parameters also were observed. Analysis of the data showed that individual neutrophils and lymphocytes from patients with sepsis were distinguishable from those of the control group with better than 84% accuracy. When average parameters were calculated from all cells of one type for each specimen, 100% accurate classification was obtained. These studies demonstrate that the image-analysis techniques used are sensitive enough to detect disease-related changes in cell morphology that are generally too subtle for reliable detection by the human eye. Future experiments will determine the specificity of this test for bacterial infections and will explore the possibility of using image analysis techniques on peripheral blood to detect and monitor a wide variety of diseases.

Cytodiagnosis↗

PubMed1982

Improved mass determination of isolated biological objects by transmission electron microscopy and scanning microdensitometry.

A modification of the classical method of Bahr and Zeitler for dry mass determination of isolated biological objects is described. The method uses a conventional transmission electron microscope (TEM) and a computer-controlled scanning microdensitometer. The performance of the modified method has been investigated by applying it to model specimens (polystyrene latex spheres). The method offers significant improvements over the existing TEM-based mass determination method.

Computers↗

PubMed1981

Thionine-Feulgen-Congo red staining of cervical smears for the BioPEPR image-analysis system.

A staining method developed for use with BioPEPR (Biological Precision Encoding and Pattern Recognition), an automated image-analysis system for cervical smears, is described. The stain is a combination of the Feulgen procedure, with thionine-SO2 as the Schiff reagent, and Congo red, which is used as a counterstain. The stain resulted in smears suitable both for microscopic diagnosis and for BioPEPR measurements made on photonegatives at a single wavelength 545 nm. A high level of reproducibility and accuracy of nuclear and cytoplasmic area measurements was obtained. Nuclear integrated optical density could be well measured and was shown to be useful in discriminating between normal and abnormal cells. Using a combination of morphologic features, a high level of cell classification accuracy was reached. The possibility of using the stain for more detailed studies is discussed.

Autoanalysis↗

PubMed1981

Thionine-Feulgen Congo Red -- a new staining technique for automated cytology.

A new staining method has been developed for an automated pre-screening device for cervical smears called BioPEPR. The method is a combination of the Feulgen technique with thionine as th Schiff reagent, and congo red. Thionine and congo red have absorption maxima at 585 nm and 500 nm respectively. The staining results in cells with an orange-red cytoplasm and brownish-blue nucleus. These smears can e easily screened using a normal microscope. The BioPEPR system scans photonegatives of the smears that are made at a magnification of ten using monochromatic light of 545 nm. The staining facilitates good discrimination between background and cytoplasm and between cytoplasm and nucleus, allowing morphologic parameters such as cytoplasmic area, nuclear area and nuclear integrated darkness to be well measured.

Autoanalysis↗

PubMed1981

The development of a cervical smear preparation procedure from the BioPEPR image analysis system.

The preparation procedure for the BioPEPR automated image analysis system is described. Cervical cells are collected in a preservative solution and disaggregated by an automated syringing apparatus, giving about 50% single cells. After centrifugation, the preservative solution is discarded, 2% polyethyleneglycol in 50% ethanol (carbowax) is added, and the cell solution is automatically spread onto a glass slide, resulting in a cell density of about 50 cells/sq mm in the central area of the smear. Increasing cell density is shown to lead to a gradual linear decrease in single cells. All preparation steps have been critically evaluated, and the possibility of implementing this preparation procedure in a fully automated system is discussed.

Autoanalysis↗

PubMed1980

Field test results using the BioPEPR cervical smear prescreening system.

BioPEPR is a cathode ray tube scanning device that has been developed for the prescreening of cervical smears. Cervical samples are collected in suspension, syringed, counted and spread across a microscope slide. Feulgen-Thionine with Congo Red is used as the staining procedure. Fields of 6 X 8 mm are scanned at 1 mu resolution, using an intermediate photographic step. Morphologic parameters of the cells are measured, as called for by a hierarchical decision strategy. Analysis speed is currently about 4 min per smear; improvements of at least a factor of four are expected. A field test of BioPEPR is being undertaken in cooperation with a local population screening program. In the study two smears are made from each woman; the first is prepared according to the Papanicolaou technique while the second is prepared and stained according to the BioPEPR methods. In addition to smears from the population screening program a number of possibly abnormal smears are obtained from several gynecological clinics. To date approximately 3500 "second" smears have been analyzed by the BioPEPR system. The results show a missed positive rate on the order of a few percent (no missed positives were more severe than a slight dysplasia), and a false alarm rate of about 24%. A further analysis of the age distribution of the false alarm rate shows that a large proportion came from women above the age of 50; the false alarm rate is about 20% for women under the age of 50.

Adult↗

PubMed1979

BioPEPR: a system for the automatic prescreening of cervical smears.

A feasibility study has indicated that a Prescion Encoding and Pattern Recognition (PEPR) cathode ray tube prescreening system for cervical smears can be both accurate and fast. Smears are prepared using a syringing technique and are stained with a Feulgen-type nuclear stain and a protein counter-stain. The use of film as an intermediate step between the cells and Bio PEPR allows the scanning of fields as large as 8 x 8 mm. The morphological features of the cells are measured as directed by a hierarchical decision strategy. Additional programs detect artifacts, overlaps, and leukocytes. For clean samples, false positive and false negative rates on the cell level have been obtained that will allow acceptable smear level rates (10% false positive, 1% false negative). These rates have been reached without compromising the required speed goals of 120 to 180 smears per hr. The efficiency of the system is dependent on the quality of the smears. Measurements on a set of 192 routinely prepared smears indicate acceptable false negative rates and a false positive rate of about 18%. A reduction of this rate is expected with small improvements in cell preparation and measuring software, leading to the overall system efficiency required for commercial feasibility.

Carcinoma in Situ↗

PubMedDate not supplied

CYTYC Corporation.

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Clinical Trials as Topic↗