Fast imaging in flow: a means of combining flow-cytometry and image analysis.

The morphological identification of cells by flow cytometry is difficult. Usually cell sorting and microscopical analysis have to be used in addition. Morphological analysis is simplified by taking cell pictures from a range of particular interest immediately during flow cytometric analysis. Instruments using the video scanning technique for fluorescence imaging are slow and expensive (8, 10). Morphological information can also be obtained by transmission imaging of cells in flow, which requires shorter exposure times. Therefore a cell volume activated flow imaging device has been developed which operates at flow speeds up to 5 m/sec and which depicts transmission images of selected cells on a 16-mm film by a nsec flashlamp illumination. An electronic unit detects the particles in the optically accessible orifice, performs the pulse height analysis, triggers the flashlamp if particles are in the preselcted range of interest and feeds the film. The instrument is capable of delivering up to 150 pictures per second and works either as a flow microscope in which the cells in the preselected volume range are directly observed, or as a picture system in which the cell pictures are stored on the 16-mm film for documentation or for image analysis.


Detection and discrimination of individual viruses by flow cytometry.

A new flow cytometer with a very small observation volume has been developed to detect individual viruses with good resolution, and has been used to discriminate between two types of viral particles based on differences in their light scattering. Measurements of light scattering and fluorescence made with such an instrument can provide a basis for quantitative analysis and sorting of viruses and other particles in the micron and submicron size range.


Multiangle light-scattering analysis of murine teratocarcinoma cells.

Stem cells of the mouse testicular teratocarcinoma are capable of giving rise in vivo and in vitro to a wide variety of cell and tissue types representative of each embryonic germ layer. Multiangle light-scattering measurements in a flow system have been made on these stem cells and on a variety of their differentiated derivatives. This technique is capable of distinguishing the stem cells from parietal yolk sac cells, visceral yolk sac cells, neuronal cells and squamous cells. However, multipotential stem cells cannot be distinguished from stem cells that are restricted in their development to a single pathway.


Simultaneous flow cytometric DNA and volume measurements of bone marrow cells as sensitive indicator of abnormal proliferation patterns in rat leukemias.

Simultaneous flow cytometric DNA and volume analysis of normal rat bone marrow cells shows three populations of nucleated cells with different mean volume. Each of these populations proliferates in a distinct cell cycle (alpha, beta, gamma). Normally the alpha-cell cycle has the highest amplitude, the beta-cell cycle is intermediate, and the gamma-cell cycle is low. The alpha-cell cycle was very significantly depressed and the beta + gamma-cell cycle was increased in three different rat leukemias (L5222, Shay, BNML), growing on three different rat strains (BDIX, Holtzmann, Brown Norway). The two parameter analysis further revealed that cells of the beta + gamma-cell cycle were slightly hyperdiploid and hypertetraploid in leukemic animals. The decrease of the alpha-cell cycle and the hyperploidies were more sensitive indicators for the abnormal proliferation pattern than the analysis of one parameter DNA distributions which remained within normal limits in all three leukemias.


Cell differentiation based on absorption and scattering.

Improvements of the flow system allow calibrated cell length measurements down to less than 2 micron at a very high rate. An optical index match to plane viewing windows perpendicular to the optical axis in the flow system keeps the axial symmetry for forward scattered light. Cell size, axial light loss and scattering intensity within different angles were found to be powerful tools to differentiate cell populations. Red cells were analyzed according to various cell surface structures. Lymphocyte populations isolated from different parts of the lymphatic system in rats have been distinguished. Experimental tumor cells showed typical data pattern after different chemical treatments.


Flowcytometric evaluation of the DNA distribution in isolated pancreatic islets from normal and diabetic mice.

Pancreatic islets from C57BL/KsJ-db/db, and +/+ mice were isolated by collagenase. After isolation the islets were transferred to a hypotonic ethidiumbromide solution with 0.3% of the detergent Nonidet P40. After vortexing, the samples were analyzed in a BioPhysics Cytofluorograf 4802A. The DNA histograms were divided into 2c, 2-4c, 4c and 8c fractions under the assumption of a constant rate of DNA synthesis during the 2-4c phase. In comparison with normal mice, we found that diabetic mice had a lower fraction of 2c nuclei and a higher fraction of 2-4c, 4c, and 8c nuclei. These results obtained by flow cytometry are in agreement with results obtained by 3HTdR incorporation and by cytophotometry on histological sections.


Immunofluorescence of histone H1 in stimulated lymphocytes measured by flow cytophotometry.

The modification of histones or their redistribution during the transition from actively transcribing chromatin to the heterochromatic chromosomes seems to play a major in regulation of gene expression. The purpose of this study was to monitor the change in immunofluorescence of histone HI during phytohemagglutinin stimulation in peripheral lymphocytes. The histone antigens were prepared from pig thymus, proven to be pure by gel electrophoresis and repeatedly injected as RNA-complexes into rabbits. The antihistone HI antiserum titer was 1:4000, and there was no cross-reactivity with other histone fractions as shown by microcomplement fixation tests. Affinity chromatography purified antibody after being labeled with fluorescein isothiocyanate was able to differentially stain HeLa cells as controls and those, where histone HI had been extracted by perchloric acid treatment. The measurements were done on a Los Alamos Scientific Laboratories-flow cytophotometer cell sorter. Staining peripheral lymphocytes resulted in a bimodal distribution. The increase in number of cells with high fluorescence intensity had its maximum about 20 hr before the maximum proliferative activity of the lymphocytes as measured by number of cells in S phase with the DNA-stain mithramycin.


Cytofluorometric analysis of R-Thy-1. antigens in various rat lymphocytes with different electrophoretic mobility and organ distribution.

Small bone marrow lymphocytes, which had been previously enriched by velocity sedimentation, thymocytes, lymph node cells and spleen cells were electrophoretically separated, stained with fluorescein conjugated rabbit a-rat-Thy-1. globulin and their fluorescence intensities analyzed with a flow cytophotometer. Thy-1. antigens were found in 80% of the bone marrow small lymphocytes showing low electrophoretic mobility (EPM), in all thymocytes, about 80% of which show low and the rest medium to high EPM, and in a few lymph node cells of high EPM. Thy-1. positive cells were not observed in the spleen. All fluorescence intensity histograms obtained were modal and could be properly fitted with normal curves showing coefficients of variation (C.V.) in the range of 20% to 30%. It was observed that the thymocytes of low EPM had an antibody binding affinity significantly different from that of the other stained lymphocytes. Moreover the surface antigen density decreased in the sequence: thymocytes of low EPM, bone marrow lymphocytes of low EPM and thymocytes of high EPM. The fluorescence intensity of stained lymph node cells of high EPM appeared similar to that of thymocytes of high EPM but was not evaluated precisely. Thus the two dimensional cell analysis provided by a combination of EPM and surface fluorescence of Thy-1.+ cells, allows the characterization of different lymphocyte populations which cannot be clearly identified with normal one dimensional techniques. The biological significance of the results is discussed briefly.


Efficient interaction for automated chromosome analysis using asynchronous parallel processes.

It is likely that any practical automated chromosome analysis system will be interactive. To prevent long pauses in the stream of operator interactions, it is necessary, if using standard computer hardware, to configure for asynchronous and parallel operation. A system is presented which uses several computer processors, which can support one or more operators, and which divides processing into interactive and noninteractive sections, smoothes the rate of presentation of interactions, and keeps both the operator and the computer fully employed.


DNA cytophotometry of human chromosomes.

The applicability of Feulgen-based parameters to detect variant metaphase chromosomes involved in deletions or translocations, was investigated and algorithms developed to compute such parameters. This report is focused primarily on the magnitude of the errors involved during the prerequisite procedures of photography, measurement and computation. Measurements were performed by stage-scanning of photographic negatives of Feulgen-stained metaphases. In the scanned images the initial chromosome boundaries were obtained by thresholding, while definite chromosomal areas and local background values were obtained by expansion of the initial boundaries. The integrated density profiles and the relative DNA content were computed for the individual chromosomes (straight as well as bent). Total DNA content, DNA arm ratio, as well as length and centromere index can be obtained from the profile. It was shown that under such conditions the experimental errors associated with the measurements are small compared to biologic variations (e.g., differences between homologues) and that the procedures applied allow to detect polymorphisms. In addition to this, mean and standard deviations of both DNA and length parameters are given for metaphases of five subjects. Comparison of the applicability of DNA and length parameters is realized by a classification experiment.


Slit-scan flow cytometry of mammalian chromosomes.

A flow cytometer has been constructed which measures total fluorescence and the distribution of fluorescence along isolated, stained mammalian chromosomes. In this device, chromosomes flow lengthwise at 4 m/sec through a 1-micrometer thick laser beam. The fluorescence from each chromosome is recorded at 10 nsec intervals; the sequence of recorded values represents the distribution of fluorescence along the chromosome and is stored in the memory of a waveform recorder. The total fluorescence of each chromosome is also measured and recorded. Preliminary studies show that doublets of 1.83 micrometers diameter microspheres flow with their long axes parallel to the direction of flow and that the two microspheres are resolved in the slit-scan profile. Ethidium bromide stained Muntjac and Chinese hamster chromosomes have also been slit-scanned. Centromeres were resolved in many of the Nos. 1 and 2 Chinese hamster chromosomes and the Nos. 1 and X + 3 Muntjac chromosomes.


Isolated metaphase chromosomes. II. Proteins of Chinese hamster chromosomes.

The proteins on metaphase chromosomes theoretically may be distributed ubiquitously throughout the karyotype, may be present uniquely on individual chromosomes or classes of chromosomes, or may exist in any combination of the above. Separation of chromosomes according to size using sucrose velocity gradients in high capacity zonal centrifuge rotors allows sufficient fractionation of the genome to indicate the distribution of proteins within the karyotype. Flow cytometric analysis and direct microscopic analysis were used to evaluate qualitatively the types of chromosomes present in the fractions obtained. This report is the first quantitative evidence that some of the chromosomal proteins are not distributed ubiquitously on all of the chromosomes of the karyotype.


An interactive computer system for the analysis of cell lineages.

We have developed an interactive computer system for analysing cell lineage data. It can be utilized in studies of cell motility, cell division, cell differentiation, and cell aging. It has enabled us to document the heterogeneity of human foreskin fibroblasts in culture and to propose that loss of proliferative potential may mean that cells enter a state of differentiation which makes them unable to respond to mitotic stimulation. Our method, which enables us to apply immunological and cytochemical probes after recording the history of a cell lineage, should allow us to define precisely features which uniquely distinguish cycling from noncycling cells on an individual cell basis.


Flow cytometric analysis of adriamycin-perturbed mouse mammary tumors.

The effects of a single intraperitoneal injection of adriamycin (10 mg/kg) on a fast-growing C3H mouse mammary tumor (S102F) have been analyzed volumetrically, biochemically, autoradiographically and flow cytometrically. Mathematical simulation of the data was also used to aid in the interpretation of the recovery kinetics. This dose of adriamycin did not induce regression in tumor volume but did inhibit the growth rate for 4-5 days. 3H-TdR incorporation was gradually inhibited to reach a low of 20% of control at 24 and 36 hr and then recovered back to control by 96 hr after adriamycin treatment. The flow cytometric analysis also showed a marked reduction in the relative fraction of cells in the S-phase with a minimum of 23% of control at 72 hr; however, in contrast to the 3H-TdR incorporation data, the fraction of cells in the S-phase was only at 39% of control at 96 hr after the adriamycin injection. Since the 3H-TdR incorporation data disagreed with the flow cytometry data, autoradiographic analysis was also done at selected times after the adriamycin injections, and qualitatively, this analysis confirms the flow cytometry data in that the labeling index was 29% of control at 96 hr after adriamycin. The mitotic index also dropped from 8 to 1%, respectively, for controls and at 96 hr posttreatment. The degenerate index was about 1% in control tumors and no increase was observed in treated tumors. Adriamycin-induced cell-cycle delay occurs predominately in G1 and G2 but there is also an apparent minor delay in the transit across the S-phase and some apparent cytotoxicity in G2 and/or M. The long delay in volumetric growth appears to be due to the extended cell-cycle delay rather than extensive cell killing.


Cell-cycle phase-dependence of drug-induced cycle progression delay.

The effect of adriamycin on cell cycle phase progression of CHO cells synchronized into the various phases of the cell cycle by elutriation was investigated by high resolution pulse cytophotometry. Cells treated in all phases of the cell cycle showed delay in their subsequent progression. In addition to the wellknown block of cells in the G2-phase, a delay in passage of cells from G1 to S and a decreased rate of transit through the S-phase were observed. A broadening of the DNA distributions of the treated cells was observed after cell division indicating induction of chromosomal abnormalities.


Multiparameter kinetic analysis of killer cell initiation by using immune RNA.

By treating nonsensitized C57BL/6J spleen derived lymphocytes with EL-4 tumor cell directed xenogeneic extracted RNA we were able to monitor early changes in cellular DNA content by flow cytometric (FCM) analysis and 3H-thymidine uptake. These kinetic parameters were correlated with cell mediated cytotoxicity which appeared as early as 8 hr after activation as measured by release of chromium-51 from labeled EL-4 target cells. Flow cytometric analysis and 3H-thymidine uptake data shown peak S phase activity at 72 hr. Maximum cytotoxicity was observed at 48 hr. Cell cycle kinetic parameters were correlated with the appearance of cell mediated cytotoxicity.


An immunocytochemical approach to cell kinetics automation.

Antibodies specific for 5-bromodeoxyuridine (BrdUrd) can be used to measure labeling indices in an automated system by image analysis. The antibody, used with an indirect immunoperoxidase technique, will detect de novo DNA synthesis subsequent to growing the cells for various time intervals in 5-bromodeoxyuridine-containing medium. Asynchronously growing CHO cells were pulsed with 3H-5-bromodeoxyuridine, fixed, denatured and then stained with anti-bromouridine antiserum. Peroxidase-coupled goat anti-rabbit IgG was used as the secondary antibody, and slides were stained with diaminobenzidine. Cells which are positive display a reticular pattern indicative of replicating chromatin. "Labeling indices" were generated by scanning the nuclei by TV image analysis. The percentage of labeled cells by the immunocytochemical technique correlates well with that found by autoradiography. Some of the applications of this automated method include cell kinetics and analysis of S-phase by pattern recognition technique.


Flow cytometric analysis of DNA content for ploidy determination in human solid tumors.

Flow cytometric studies of cellular DNA content were conducted in 26 patients with a variety of neoplasms. Cell dispersal was achieved with pepsin treatment, and a combination of ethidium bromide and mithramycin was used as DNA specific staining procedure. All measurements were conducted with a new sheath flow chamber in a PHYWE ICP 11 pulse cytophotometer. All but one patient with multiple myeloma had unimodal tumor cell DNA distributions. With human granulocytes as reference standard, 24 of 26 tumors were aneuploid; and of these, 23 showed varying degrees of hyperdiploidy. Except for one patient, ploidy abnormalities were stable on repeat examination.


Cell sorter analysis of carcinogen metabolites in human tissues.

A fluorescence -activated cell sorter (FACS-II) was used to examine biochemical parameters in a heterogeneous population of cultured human lymphocytes. Incubation of cells in the presence of benz(a)anthracene (BA) during culture was employed to induce the enzyme system which metabolizes carcinogens. Carcinogen metabolism was assayed directly by measuring the phenolic metabolites of cells exposed to benzo(a)pyrene (BP). Metabolism of benzo(a)pyrene was measured in single cells and was determined to be greater in the larger cells than in the smaller cells of the cultures. For a given size of cells, the enzyme activity was greater in those exposed to benz(a)anthracene during culture. In some studies, viable cells were first sorted by size and subpopulations assayed for the o-deethylation of the compound, ethoxyresorufin, which measures more specifically the activity of cytochrome P-448. Larger cells had higher levels of enzyme activity than smaller cells in agreement with the direct determinations above. It is possible to measure carcinogen metabolism in other tissues by using the techniques described here.


Automated cervical cytology screening: performance requirements and instrument evaluation.

Continuing progress towards automation of cervical cancer screening requires that criteria for clinical acceptability of automated systems be defined, and that methods be devised for effectively evaluating new technology. The potential roles of automation in cervical cancer detection, performance requirements, instrument evaluation and useful contributions from tuberculosis screening, automated white blood cell differential counting, signal detection theory and decision theory are discussed.


The diagnostic significance of nuclear deoxyribonucleic acid measurement in automated cytology.

Flow cytometric analysis of cytologic samples from four different organs shows that nuclear DNA content of malignant cell populations depends to a large extent on organ of origin of the tumor. This fact must be considered in planning screening systems.


A screening system for cervical cancer cytology.

A system for screening cervical cytological preparations is described which employs the Leitz Texture Analyzer System (E. Leitz, Rockleigh, N. J.) quantitative staining with acridine orange, and a fluorescence standard. The instrumentation scans cells on microscope slides and detects objects which it interprets to be nuclei with excess total nuclear green fluorescence intensity (Previous results employing manual measurements have indicated that normal nuclei do not produce total nuclear green fluorescence greater than a specific absolute intensity level). Detected objects are identified by visual observation. Cells (102,000) from 65 patients (29 normal, 36 abnormal) have been examined. In each abnormal sample, at least one abnormal cell was detected. In over half of the samples, three or fewer other objects (e.g. clumps of polymorphonuclear leukocytes) were detected. These are easily distinguishable from single nuclei, and could be discarded by someone with minimal cytological training.


Proximity of lectin receptors on the cell surface measured by fluorescence energy transfer in a flow system.

Molecules of the lectin concanavalin A have been labeled separately with the fluorescein and rhodamine chromophores and jointly bound to the surface of transformed Friend erythroleukemia cells. The two dyes constitute an ideal donor-acceptor pair for fluorescence resonance energy transfer thereby permitting the determination of the proximity relationships between bound ligand molecules and the corresponding surface receptors. The transfer efficiency at saturation (about 57%) was measured in a multiparameter flow system using laser excitation at 488 nm and detection of fluorescein and rhodamine emission intensities as well as the emission anisotropy of the rhodamine fluorescence for each cell. The degree of energy transfer was estimated from the quenching of donor emission, the sensitization of acceptor emission, and the depolarization of acceptor fluorescence. The system has been modeled according to a formalism developed by Gennis and Cantor (Biochemistry 11: 2509, 1972). We estimate the separation between the surfaces of bound lectin molecules at saturation to be 0-40 A, a range possibly characteristic for micropatches induced by ligand binding.


Visualization of multidimensional spectra in flow cytometry.

Flow data from a cell sorter have been processed by hardwired circuits which include amplification, discrimination, coincidence requirements, peak sensing and holding, A-D conversion, and a computerized pulse height analysis with storage of the spectra obtained. Two dimensional spectra can be stored directly in memory, on tape and disk. Three and four parametric cellular events can be recorded on line during the flow measurement in a sequential mode on tape for subsequent recall. Simple processing of these data can be performed for displaying of two dimensional projections from these multidimensional spaces based on threshold conditions for the remaining parameters. Interfaced transmission of the stored data to a large scale computer enables more sophisticated data analysis. Data reduction by means of a multidimensional probability analysis has been carried out in order to transfer the spectra to a computerized picture system for display. This system creates perspective two-dimensional images from a three-dimensional data space. Frequency can be converted into grey levels. Hard copy in color (color as the third dimension and color intensity as frequency) simplifies the visualization of multiparametric flow data sets.


Quantitative cytology of the positive region in flow sorted vaginal smears.

Fifty-one gynecologic specimens were collected from three women's hospitals and mailed in a prefixed status to our laboratory. The specimens were classified into a negative, a suspicious, a postradiation, and a positive group. After single cell dispersion the samples were stained for DNA and protein, analyzed, and sorted in the dual laser equipped Heidelberg flow analyzer sorter (HEIFAS). Particles with elevated DNA values (beyond 3.5 ploidy) and with intermediate protein values were sorted as the positive fraction directly on microscopic slides. After restaining according to Papanicolaou, they were re-evaluated cytologically and identified as tumor cells, dysplastic cells and false alarms. The latter consist of doublets and aggregates of more than two cells, binucleated cells, sperm aggregates and epithelial cells contaminated with bacteria. The different groups showed significant differences regarding the total rate of aggregates to single cells. In general, false alarms were very frequent in the positive region and impeded the statistical classification of the sample. The reduction of false alarms is a prerequisite for prescreening with flow instrumentation.


Flow cytometry of human gynecologic specimens using log chromomycin A3 fluorescence and log 90 degrees light scatter.

Flow cytometry and electronic cell sorting are being investigated to screen gynecologic specimens for cervical neoplasia. Cellular DNA content is quantitated by Chromomycin A3 fluorescence and cell size is quantitated by 90 degrees light scatter; the logarithms of the measured intensities are used to produce a two parameter histogram. To determine the cell types responsible for signals in various histogram regions, systematic electronic cell sorting is performed. The sorted fractions are sedimented into microscope slides and stained by the Papanicolaou technique. The cells in each fraction are identified by conventional cytomorphologic criteria. Morphologic analysis of sorted cells reveals histogram regions corresponding to specific cell types. One very important region contains the highest concentration of signals from abnormal cells and is therefore the best region to analyze for specimen abnormality. However, because a significant number of signals in this region are from normal cells, specimens cannot be diagnosed by their analysis. Another important histogram region is composed primarily of signals from endocervical columnar and metaplastic cells. The presence of such cells is a good criterion for specimen adequacy, therefore analysis of signals in this region is essential to assess specimen adequacy for automatic screening.


Interactive display and analysis of data from bivariate flow cytometers.

An interactive computer program, SWELL, displayss and analyzes bivariate distributions generated by flow cytometers. SWELL is modular with options available via a menu, is written in Fortran, and utilizes a video color display system. Data are accumulated as a bivariate distribution that is transferred to the computer as a 64 x 64 matrix. For ease of visualization, matrices are displayed in pseudocolor. The distribution values are broken into eight ranges and each range is represented by a color. Each element of the matrix is then displayed in its assigned color. To allow pooling and comparison, distributions are aligned, edited, and standardized. Unknown samples are pooled or analyzed singly and compared to the normal pool by subtraction. Differences are displayed as pseudocolor matrices of sign, magnitude, or statistical magnitude in units of standard deviation. This latter display, scaled to tolerance limits, readily reveals regions of significant difference between normal and abnormal samples. Counts within such regions can be compared to diagnose samples automatically.


False alarms in a slit-scan flow system: causes and occurrence rates. Implications and potential solutions.

A slit-scan technique was developed as a basis for an automated prescreening system for gynecologic cytology. A flow system based on this technique was fabricated and tested and results indicated that false alarms (misclassification of objects or events from normal specimens as abnormal) are the greatest remaining obstacle to development of an automated prescreening instrument. A dual view correlation system was fabricated to provide exact image-contour correlation in flow and permit precise determination of causes and occurrence rates of false alarms. This paper presents data from correlation analyses of 23 normal cytologic specimens. Major causes of false alarms and their implications to automated prescreening are discussed. A technique that would eliminate the majority of false alarms in flow is presented.


Preselection of alarms in a hybrid system for screening of cervical cancer.

In this report, a preselection of alarms in a system for automated screening of cervical cancer based on depositing the cell sample linearly as a "cell trace" on a tape and analyzing it at different decision levels with increasing complexity, and preliminary results on analyzing cervical material with this system are discussed. The "cell trace" is analyzed with the slit-scan technique. Six parameters are computed: 1) cellular diameter; 2) nuclear diameter; 3) nuclear fluorescence (acriflavin-Feulgen) as nuclear DNA; 4) cellular fluorescence; 5) nuclear to cytoplasm ratio (N/C ratio); and 6) nuclear density. At present, only nuclear fluorescence is used to define a decision boundary between normal and potentially atypical cells. Under this criteria the slit-scan analysis leaves 5% of the events in a sample that must be rechecked at a second decision level in normal cell samples. A further reduction is expected when several slit-scan parameters are used at the first decision step. All events declared suspicious will be investigated in more detail by a two dimensional image analyzing system where the fluorescence image is generated by a laser scanning system. Results obtained in preliminary experiments are discussed in this paper.


Progress report of the TUDAB project for automated cancer cell detection.

Two methods for high resolution cell image data acquisition are applied routinely. Cells are either scanned by a computer controlled fast scanning microscope photometer (SMP) or a TV-camera. The software system for digital image analysis was completely revised and implemented on the PR 330 minicomputer. The system contains codes for primary cell data acquisition, segmentation of cells, cell feature extraction and statistical cell analysis. With this system, SMP and TV scanned cell data bases of PAP stained cells in vaginal smears, grouped into several classes, have been built up. Each data base contains 34 primary features and 20 feature combinations for each cell. A linear discriminant analysis is applied routinely for cell classification. The present state of the system and its operation are described, cell features and classification results are shown, and future steps for a prescreening strategy are discussed.


An image analysis system for cervical cytology automation using nuclear DNA content.

An experimental computer/image analysis system has been used to investigate cytology automation techniques based on nuclear DNA measurement and morphological artefact rejector tests. The system automatically measures and normalizes the integrated optical density of cell nuclei in specially prepared cervical cytology specimens, and selects any objects with abnormally high values for further analysis. These are then analyzed by morphological and densitometric tests designed to eliminate false positive signals caused by non-nuclear artefacts. The coordinates of the remaining abnormal nuclei are recorded so that they can subsequently be relocated and examined by a cytotechnician. Preliminary results are given showing the measurement accuracy of the system and the performance of the artefact rejection tests.


High resolution segmentation of cervical cells.

A major problem in the automation of cervical cytology screening is the segmentation of cell images. This paper presents the present status of the work on that problem at the University of Uppsala. A dual resolution system is used. Suspect malignant cells are located at 4 mu resolution. Each such cell is rescanned at 0.5 mu resolution at two different wavelengths, 530 and 570 nm. The nucleus and the cytoplasm are isolated each by two independent methods. For the nucleus adaptive thresholding in the histogram of the 570 nm image and a contouring in a radially transformed version of that image is used. For the cytoplasm a two dimensional thresholding in the 2D histogram and a contouring in a radially transformed version of the 530 nm image is used. If the two nuclear masks agree the surrounding area is checked for disturbing objects. If also the cytoplasm masks agree and are without disturbing objects the whole cell is accepted. The result of the cytoplasm masks agree and are without disturbing objects the whole cell is accepted. The result of the segmentation is thus three categories; free cells, free nuclei and rejected objects. The shape of the objects belonging to the former two categories is checked and irregularly shaped ones are rejected as probably consisting of several overlapping nuclei. Cells passing also this test are classified as normal or malignant. The experience from using this algorithm is discussed and areas for further research are pointed out.


A new method for fluorescence immunoassay using plane surface solid phases (FIAPS).

A method distinguished by high sensitivity, low non-specific binding, easy handling, and broad applicability with respect to various antigens is described. Films of polymethyl-methacrylate with plane surfaces were selected as solid phase for adhesive or covalent binding of different antigens (DNA, histone, human, rabbit or goat immunoglobulins). Proteins were covalently bound to the films by the azide method (Orth and Brummer, 1972). Polymethylmethacrylate films thus coated had a negligible autofluorescence and gave minimal non-specific binding of protein. Coated films were used for specificity control of FITC-labeled antibody preparations and in the double antibody and sandwich techniques for detection of antibodies or antigens in sera from man, rabbit and goat. FITC-conjugated hyperimmune antibody, in some cases purified by immunoadsorption was used as second antibody in indirect techniques. The amount of fluorescent-labeled antibody bound per unit of surface area of film was measured by incident light with a Zeiss-Axiomat fluorescence microscope equipped for fluorescence photometry and an uranyl acetate glass plate was used as a standard. The technique appears superior to present methods of quantitative immunofluorescence analysis.


Preparation of functionalized derivatives of inulin: conjugation of erythrocytes for hemagglutination and plaque-forming cell assays.

A method is described for preparing derivatives of alkali-stable polysaccharides for coupling to immunogen carriers or to sheep red blood cells (SRBC) for use in hemagglutination (HA) and plaque-forming cell (PFC) assays. Inulin, a beta (2 leads to 1)-linked polyfructosan was partially derivatized with carboxyl, aminoethyl or (p-aminophenyl)butyryl groups; the latter derivative was coupled to SRBC following diazotization. Optimal conditions for the sensitization of SRBC with inulin were given. The immunological reactivity of the inulin molecule was unaffected by the derivatization reactions, and high, reproducible anti-inulin HA titers for inulin-binding myeloma proteins were found using these specifically sensitized SRBC. The sensitized SRBC were stable for assays for over 2 weeks. Problems with spontaneous agglutination or distortion of sensitized SRBC, normally seen in other procedures, e.g., methods using stearoyl-inulin, were not encountered.


A simple micro-assay for neutrophil bactericidal activity.

A micro-titre assay of neutrophil intracellular bactericidal activity is presented which requires only a relatively small number of cells and which is simple to perform, making it suitable for use in a clinical situation.


Virulence of Escherichia coli K1 in adults.

Of 137 cases of Escherichia coli bacteremia in adults at a general hospital, 16 (12%) were caused by E. coli K1. The case records of 15 patients with E. coli K1 and 48 patients with other E. coli revealed that the patients with E. coli K1 had an average age of 54, while those with other E. coli had an average age of 61 (P greater than 0.05). There was no significant difference between the profiles of underlying disease in the two groups. No patients with E. coli K1 bacteremia died, while 16 of 48 patients with non-K1 bacteremia died (P =0.006). This difference was statistically significant in those patients with ultimately fatal disease (P = 0.038) but not in those with non-fatal disease (P = 0.16). These findings suggest that E. coli K1 is cleared more easily by adults than are other E. coli.


Target tissues associated with genital infection of female guinea pigs by the chlamydial agent of guinea pig inclusion conjunctivitis.

Female guinea pigs were experimentally infected in the genital tract with the strain of Chlamydia psittaci that causes guinea pig inclusion conjunctivitis. Chlamydiae were found frequently in superficial squamous epithelial cells of the exocervix, along with heavy involvement at the squamocolumnar junction. In this zone chlamydiae were observed in columnar cells, but inflammation and chlamydial inclusions were not observed in true endocervical epithelium. These observations were supported by results of immunofluorescence microscopy. Electron micrographs revealed typical chlamydiae within surface epithelial cells at the squamocolumnar junction; various stages of the growth cycle (elementary, reticulate, and intermediate bodies) were also present. Cytopathologic features were not remarkable, but peripheral distribution of organelles, rarefaction of the cytoplasm, and loss of microvilli were observed.


Adherence, augmented adherence, and aggregation of polymorphonuclear leukocytes.

Adherence of polymorphonuclear leukocytes to nylon fiber was found to be plasma-independent and distinct from the processes of augmented adherence, leukocyte aggregation, and inhibition of random leukocyte migration, all of which are dependent on "activated" plasma. Nylon fibers were unable to "activate" plasma, in contrast to the complement-activating agent zymosan. Prior incubation of plasma with antiserum to the third component of complement (C3) inhibited aggregation of polymorphonuclear leukocytes by plasma incubated with zymosan, and heat-inactivation blocked augmentation of adherence by treatment of plasma with zymosan.


Interaction of group A streptococcal lipoteichoic acid with bovine myelin basic protein.

Group A streptococcal lipoteichoic acid (LTA), a polyglycerol phosphate ester linked with fatty acids, formed precipitin lines in agar gels with the positively charged myelin basic protein (MBP) isolated from bovine brain. The LTA-MBP complexes were formed with deacylated teichoic acid and were not inhibited by monomeric glycerol phosphate, a finding indicating the participation of the polyglycerol phosphate (PGP) backbone of LTA in the reaction. Following interaction with PGP, MBP inhibited the agglutination of LTA-sensitized erythrocytes by induction of antibodies to LTA, directed against the PGP antigenic determinant. The amplification of the humoral immune response to the insoluble complex of LTA and MBP was of particular interest in view of the lack of immunogenicity of either LTA or MBP alone.


Synergism of ampicillin and gentamicin against obstructive pyelonephritis due to Escherichia coli in rats.

Rats with obstructive pyelonephritis due to Escherichia coli were treated for different intervals with ampicillin and gentamicin either alone or in combination. The combination of ampicillin and gentamicin was synergistic in vitro and significantly more effective in vivo than was either drug alone. After treatment for 10 days, the combination of ampicillin and gentamicin was the only regimen that sterilized all of the pyelonephritic kidneys. The importance of achieving sterility was illustrated by the observation that severe infection and acute pyelonephritis recurred after religation of the ureter in 12 (71%) of 17 ampicillin-treated animals that had harbored as few as 46 organisms per kidney before ligation. A synergistic combination of antibiotics rapidly sterilizes obstructed pyelonephritic kidneys. In view of the particular risk of renal infection in the presence of urinary obstruction in humans, synergistic antibiotic combinations may be useful in the treatment of obstructive pyelonephritis in humans.


Electron microscopic definition of surface antigens of group B Streptococcus.

Strains representing each of the five serologically distinct types of group B Streptococcus and variant strain 090R, which is devoid of type-specific polysaccharide, were studied by electron microscopy after incubation with various ferritin-conjugated antibodies. Ferritin-conjugated types Ia, II and III antibodies localized on homologous cells in a pattern that defines the capsular location of the type Ia, II, and III polysaccharide antigen. Type Ib and Ic cells have surface antigens to which ferritin-labeled antibodies to both capsular polysaccharide and a common surface protein attach.


Cell-mediated immune responses in sporotrichosis.

Cell-mediated immunity (CMI) was evaluated in five patients with cutaneous sporotrichosis and six patients with systemic sporotrichosis. Whereas patients with cutaneous disease showed normal CMI, the patients with systemic disease had significant abnormalities in CMI. Most patients exhibited responses to a sporothrix antigen, measured either in conventional assays of lymphocyte transformation or in preincubation assays. Two patients with protracted illnesses and continued abnormalities in CMI were treated with transfer factor and showed improvement in parameters of CMI and control of their disease.


Prevention of pyelonephritis due to Escherichia coli in rats with gentamicin stored in kidney tissue.

Although gentamicin is known to accumulate and persist in the kidneys after systemic administration, its antibacterial activity at this site has not been determined. In the present study the accumulation of gentamicin in rat kidneys before infection prevented obstructive pyelonephritis due to Escherichia coli despite heavy urinary tract infection on the obstructed pelvis; thus the kidneys were protected against infection in the absence of effective levels of gentamicin in the urine. Stored gentamicin also protected pyelonephritic rats from relapse after complete obstruction of the kidneys. The level of antimicrobial activity of gentamicin in whole kidney tissue was 95% less than that anticipated on the basis of levels measured after dilution of kidney tissue homogenates; this low level of activity apparently was due in part to high concentrations of solutes. In view of these results in rats, the possibility must be considered that despite reduced activity, gentamicin storage might be useful in the prophylaxis of kidney infection in patients with abnormalities of the urinary tract. In the treatment of established kidney infection, the dose of gentamicin could be reduced and the interval of its administration increased for minimal toxicity.


Different protection rates in various groups of volunteers given subunit influenza virus vaccine in 1976.

Different rates of protection were observed in various groups of volunteers given trivalent subunit influenza virus vaccine during an epidemic caused by A/Victoria/3/75 strains of influenza virus in Melbourne, Victoria, Australia, in 1976. The degree of protection varied from 80% protection from infection in one group to a moderation in the severity of clinical illness in a geriatric group. The response to immunization may depend on the previous experience of the vaccinees, and it may be necessary to use different dose schedules in different groups for optimal protection.


Antimicrobial therapy of septicemia due to Klebsiella pneumoniae in neutropenic rats.

Three different isolates of Klebsiella pneumoniae, highly sensitive to amikacin but varying  in susceptibility to cefazolin, were injected intraperitoneally into neutropenic rats. Animals were treated every 8 hr for 72 hr with saline (controls), cefzolin (full dose, 40 mg/kg; one-fourth dose, 10 mg/kg), amikacin (full dose, 8 mg/kg; one-fourth dose, 2 mg/kg), or a combination of both drugs at either full dose or one-fourth dose. All drugs were given intramuscularly. Combination therapy with full doses produced higher mean bactericidal titers in serum and more rapid clearance of bacteria from blood and peritoneal washings. However, cumulative mortality at 72 hr in rats treated with amikacin plus cefazolin in full doses (24%, 23%, and 44%) was not significantly different from mortality in rats treated with amikacin alone (34%, 17%, and 62%). Results with cefazolin alone were not significantly different from the mortality in control animals for two of the three challenge organisms. When the minimal inhibitory concentration of cefazolin was less than or equal to 8 micrograms/ml, in vivo synergy was suggested by the similar survival rate obtained with a combination of a one-fourth dose of each agent and with amikacin alone in a full dose. These results demonstrate the relative ineffectiveness of cefazolin for therapy of klebsiella septicemia and suggest that in vivo antimicrobial synergy occurs in combination therapy against strains of bacteria relatively sensitive to cephalosporins.


Investigations in mice on the potentiation of resistance to infections by a new immunostimulant compound.

BM 12.531, 2-[2-cyranaziridinyl-(1)]-2-[2-carbamoylaziridinyl-(1)]-propane, a new immunostimulant compound, increased the resistance of mice to infection with Candida albicans. Because BM 12.531 had no fungistatic activity in vitro, it is proposed that the therapeutic effect of BM 12.531 is caused by the stimulation of cell-mediated immunity. Administration of cyclophosphamide alone increased the mortality among mice infected with C. albicans and Pseudomonas aeruginosa, but when BM 12.531 was then administered to these animals, the mortality was reduced. Among mice with acute Escherichia coli infection, a synergistic effect of chloramphenicol and BM 12.531 was demonstrated.


Immunofluorescence determination of the pathogenesis of infection with influenza virus in mice following exposure to aerosolized virus.

The pathogenesis of infection with influenza A virus in mice was studied by exposure of specific pathogen-free mice to aerosols of influenza virus and by monitoring of mortality, viral titers in lung homogenates, and presence of viral antigens in respiratory cells as determined by immunofluorescence. In two experiments with different death rates (100% and 43%), viral antigen accumulated in the epithelial cells lining the airways, in alveolar macrophages, in alveolar cells, and in visceral pleura. By enumeration of the number of airways, alveolar macrophages, and alveolar cells containing influenza viral antigens at different intervals after exposure to the viral aerosol, it was determined that viral replication occurred initially in the epithelial cells lining the airways and later extended to the alveolar macrophages and alveolar cells. This semiquantitative survey of the dynamics of influenza viral infection by aerosol indicated that the viral infection in mice was a descending process.


Enhanced isolation of Mycoplasma pneumoniae from throat washings with a newly-modified culture medium.

Two hundred throat washings, previously screened and presumed negative for Mycoplasma pneumoniae in conventional mycoplasma culture media, were retested for the organism in a modified medium (PS-4) initially developed for cultivation of a tick-derived Mycoplasma (spiroplasma). The organism was rapidly identified with an agar plate immunofluorescence procedure. M. pneumoniae was isolated from 69 (34.5%) of the 200 "negative" specimens cultured on a diphasic SP-4 medium, in contrast to 10 isolations (5%) made on conventional diphasic mycoplasma medium. This enhanced recovery of M. pneumoniae represented a combination of a superior culture medium and a more efficient identification technique. The findings suggest that these procedures might be effectively applied to the recovery of M. pneumoniae from all likely host and that improved recovery of the organism may aid in the interpretation of a number of puzzling questions about the epidemiology of M. pneumoniae infections.


Detection of respiratory syncytial virus in nasal secretions from infants by enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) was developed for detection of respiratory syncytial virus (RSV) in nasal secretions from infants with respiratory disease. RSV was detected in 23 of 29 secretions positive for RSV by tissue culture and in one of 36 samples negative for RSV by tissue culture. The ELISA was a simple rapid, and surprisingly sensitive test for identification of RSV infection in infants.


Mucosal defenses against Salmonella infection in the mouse.

Specific pathogen-free ICR (Institute of Cancer Research) mice were challenged with Salmonella orally, aerogenically, or parentally 24 hr after they received sublethal whole-body irradiation. The early growth for the sublethal inoculum was identical in irradiated and control mice. In the irradiated group, Salmonella multiplied in the liver and spleen until death of the host. Increasing the dose of irradiation reduced the size of the mean lethal dose for the intravenous, intraperitoneal, and aerogenic challenges. However, in the orally challenged mice, the 50% lethal dose dropped only 100-fold when the radiation was increased from 0 to 400 rad, with little further decrease even when the dose was increased to 800 rad. Presumably, the local gut defenses were responsible for this considerable disparity in the lethal effects of an oral vs. parenteral challenge. No evidence was found for enhanced local infection of the gut or increased involvement of the gut-associated lymphoid organs in the irradiated host. The increased mortality seen in the irradiated group seemed to be associated with a continued unrestricted growth of Salmonella in the liver and spleen when the number of peripheral blood leukocytes was at a minimum. Resistance to the sublethal salmonella challenge was eventually restored as the total counts of white blood cells returned to normal.


Inhibition of alternative complement pathway opsonization by group A streptococcal M protein.

Group A streptococcal M protein is known to be antiphagocytic; however, the exact basis for this property has not been established. In this study the hypothesis was tested that cell wall--associated M protein inhibits phagocytosis by interfering with bacterial opsonization. Two strains of group A Streptococcus pyogenes, CS44 (M+) and CS64 (an M- variant of CS44), were radiolabeled, and after incubation in serum these organisms were exposed to human polymorphonuclear leukocytes. Phagocytosis was quantitated by measurement of leukocyte-associated radioactivity. The contributions of complement and of immunoglobulin to streptococcal opsonization were evaluated by use of serum from a variety of sources. The results revealed that the M- strain was efficiently opsonized via the alternative complement pathway in a relative absence of immunoglobulins. In contrast, the M+ strain was poorly opsonized by all sera tested. These findings suggest that streptococcal M protein in some way prevents bacterial opsonization via the alternative complement pathway and that this property of M protein may partly explain its antiphagocytic characteristic.


A study of 666 strains of Candida albicans: correlation between serotype and susceptibility to 5-fluorocytosine.

The minimal inhibitory concentrations (MICs) of 5-fluorocytosine (5-FC) and the serotypes were determined for 666 strains of Candida albicans isolated from white patients in Canada. Of these strains, 495 (74.3%) were serotype A and 71 (25.7%) were serotype B. Resistance to 5-FC (MIC, greater than or equal to 25 microgram/ml) was observed in 11.3% of the serotype A strains and in 49.7% of the strains of serotype B. Most specimens were from the urogenital and respiratory tracts. The results showed the difference between the distribution of the two serotypes of C. albicans in North America and that in Europe. Serotyping of C. albicans strains by indirect immunofluorescence is a rapid means of predicting the de novo sensitivity of this year to 5-FC. The specificity of this technique for the isolated strains was approximately 79%.


Hepatic cholesterol metabolism in normo- and hyperlipidemic patients with cholesterol gallstones.

In vivo studies have shown abnormalities in cholesterol and bile acid metabolism in primary hyperlipoproteinemia (HLP). The aim of the present investigation was to determine if the increased production of cholesterol in HLP type IV can be attributed to a correspondingly high level of the hepatic 3-hydroxy-3-methylglutaryl (HMG) CoA reductase activity and if the low cholic acid: chenodeoxycholic acid synthesis ratio in HLP type II is due to some hydroxylase deficiency. Liver biopsies from 26 normolipidemic and 25 hyperlipidemic (10 type IIa, 6 type IIb, and 9 type IV) patients undergoing elective cholecystectomy were assayed for HMG CoA reductase activity, 12 alpha-hydroxylase activity, and 25-hydroxylase activity. The HMG CoA reductase activity was normal in HLP type IIa and type IIb and was increased about twice HLP type IV (P less than 0.001). The 12 alpha- and 25-hydroxylase activities were normal in all groups of patients. The results are compatible with a normal cholesterol synthesis in the liver in HLP type II. A reduced 12 alpha- or 25-hydroxylase activity cannot explain the low production of cholic acid relative to chenodeoxycholic acid in this type of HLP. The elevated HMG CoA reductase activity found in the liver of type IV patients may, however, be part of the explanation for the elevated synthesis of cholesterol often seen in these patients.


A singular perturbation approach to diffusion reaction equations containing a point source, with application to the hemolytic plaque assay.

Many cells secrete factors which diffuse and bind to receptors on neighboring cells. These processes can be described by a nonlinear diffusion equation with a point source and spatially distributed binding reaction. We show via perturbation analysis how approximate solutions can be obtained for such equations when the binding reaction is fast compared to diffusive transport. We base our analysis on an example which is of great practical importance in immunology, the hemolytic plaque technique.


Morphological changes in the endocrine pancreas in pregnant rats with experimental diabetes.

This present study has demonstrated that during normal pregnancy in the rat the number of beta-cells is increased (hyperplasia) and the volume of the individual beta-cells is increased (hypertrophy). During experimental diabetes, however, the endocrine pancreas has an impaired capacity to compensate during pregnancy. In the experimental diabetic pregnant rat the beta-cells cannot replicate due to the unfavourable metabolic environment. This could reflect the complications caused by diabetes during human pregnancy.


Effect of treatment with an agonist of luteinizing hormone releasing hormone on early maturational changes in pituitary and testicular function in the rat.

Male rats aged 30 days were injected once daily for between 1 and 7 days with 50 ng (D-serine t-butyl6, des-glycine-NH210) luteinizing hormone releasing hormone ethylamide (LH-RH agonist), and pituitary and testicular function were assessed. Treatment for 7 days significantly (P less than 0.02) inhibited maturational increases in the pituitary content and serum concentration of gonadotrophins, testicular luteinizing hormone (LH)-receptor concentration and the testicular capacity to secrete testosterone; the pituitary content and serum concentration of prolactin, the hypothalamic content of LH-RH and testicular weight were unaffected. In rats treated with LH-RH agonist, the initial (2 to 3 days) reduction in testicular LH-receptors and the capacity to secrete testosterone probably resulted from acutely raised levels of LH in the blood, whilst later effects may have resulted from the apparently chronic reduction in serum gonadotrophin levels. The latter may reflect a decrease in pituitary responsiveness to repeated stimulation with LH-RH agonist. Despite the extensive loss of testicular LH-receptors and diminished responsiveness, the concentration of HCG which significantly (P less than 0.05) increased testosterone secretion by the testis in vitro was the same (2 pmol/l) as that for testes from control rats.


Appendicitis associated with recent barium study.

There have been several reports of "barium-induced" appendicitis in the literature. When confronted with a possible case of this phenomenon, a review of the literature on the subject was carried out. The suggestion is made that there is no evidence to support a cause-effect relationship between barium retained in the appendix and appendicitis. Diseased appendices can be marked by retained barium and a higher likelihood may then exist for the subsequent development of appendicitis. Following the finding of prolonged retention of barium after contrast study, it is recommended that the patient be instructed as to the possibility of developing symptoms of acute appendicitis. Patients who present with symptoms of appendicitis should be questioned as to history of recent barium study, and x-rays should be reviewed with the possibility of finding appendoliths.


Tick toxicosis in North America.

This is a case presentation and review of an uncommon disorder, tick toxicosis. The history, epidemiology, pathophysiology, and treatment are discussed. This disorder was mentioned in diaries from the early 1800s and has been reported in 18 states and the District of Columbia. A review of 70 cases reveals that the typical patient is a female child who develops leg weakness, irritability, or clumsiness. The exact site at which the toxin induces the paralysis is unknown. Removal of the tick usually reverses the paralysis within hours. Confusing tick toxicosis with other disorders may occur, and death has resulted. This article will remind physicians to consider tick toxicosis when seeing patients with acute ataxia or ascending paralysis and to, perhaps, prevent death from an easily treatable disorder.


Properties of R plasmid R772 and the corresponding pilus-specific phage PR772.

R plasmid R772 was isolated from a strain of Proteus mirabilis and is a self-transmissible P-1 incompatibility group plasmid having a molecular weight of about 27 x 10(6). It renders bacterial hosts resistant to kanamycin. Phage PR772 was isolated as a phage dependent on the presence of R772 in bacterial hosts. It is hexagonal-shaped with a diameter of 53 nm, has a thick inner membrane and no tail. Vaguely defined appendages are sometimes apparent at some vertices and the phage possesses double-stranded DNA. The DNA has a guanine plus cytosine molar content of 48%. The phage is sensitive to chloroform and has a buoyant density of 1.26 g cm(-3). These observations suggested that the inner membrane of the phage could contain lipid. Phage PR772 differs in morphology from the double-stranded DNA plasmid-specific phages PR4 and PRR1 which adsorb to tips and sides, respectively, of sex pili coded for by P-1 incompatibility group plasmids. Phage PR772 formed clear plaques which varied in diameter. Serologically, phages PR772 and PR4 are possibly related though very distantly, but the two phages have identical host ranges. Phage PR772 adsorbed by one of its apices to tips of sex pili coded for by plasmid R772 in Escherichia coli. It also formed plaques on Salmonella typhimurium Proteus morganii and Providence strains harbouring this plasmid as well as strains of E. coli carrying plasmids of incompatibility groups N or W. The phage produced areas of partial clearing on lawns of P. mirabilis PM5006 harbouring plasmid R772, the P-1 incompatibility group plasmid RP4, the W group plasmid RSa or the N group plasmid N3, and on lawns of Providence strain P29 carrying plasmid RP4.


The isolation and characterization of three types of vitamin B6 auxotrophs of Escherichia coli K12.

Approximately 500 vitamin B6 auxotrophs were isolated from 18 independent cultures of Escherichia coli strain CR63. None grew in minimal medium supplemented with 2'-hydroxypyridoxine. Eighteen auxotrophs which had arisen independently were further characterized. All of them were defective in vitamin B6 synthesis rather than in an aminotransferase involved in vitamin B6 utilization. Two different phenotypes were recognized: 'Oxidase' mutants which grew only when supplied with pyridoxal or pyridoxal 5'-phosphate and 'Pre Pn' mutants which would also grow with pyridoxine or pyridoxine phosphate. "Oxidase' mutants were confined to a single linkage group, but data from interrupted mating experiments established that 'Pre Pn' mutants fall into two linkage groups which are possibly identical to pdxA and pdxB. All mutations in the in the pdxA region were allelic rather than located in two closely linked genes.


Synthesis of vitamin B6 by a mutant of Escherichia coli K12 and the action of 4'-deoxypyridoxine.

Mutants of Escherichia coli K12 blocked in the oxidation of pyridoxine 5'-phosphate ('Oxidase' mutants) excreted pyridoxine at an initial rate of 19 pmol h-1 (10(8) bacteria)-1, i.e.0.6 nmol h-1 (mg dry wt)-1, when starved for pyridoxal. Glycolaldehyde, L-phosphoserine, DL-serine and, to a lesser extent, L-leucine stimulated the rate of pyridoxine excretion, but there was no significant stimulation by 2'-hydroxypyridoxine. 4'-Deoxypyridoxine inhibited or stimulated growth of the "Oxidase' mutant, depending on the relative concentrations of added pyridoxal and 4'-deoxypyridoxine. It was concluded that stimulation of growth by 4'-deoxypyridoxine was due to its conversion to pyridoxal.


Uptake of trehalose by Saccharomyces cerevisiae.

Trehalose, a storage sugar of baker's yeast, is known not to be metabolized when added to a cell suspension in water or a growth medium and to support growth only after a lag of about 10 h. However, it was transported into cells by at least two transport systems, the uptake being active, with a pH optimum at 5.5. There was no stoicheiometry with the shift of protons into cells observed at high trehalose concentrations. Trehalose remained intact in cells and was not appreciably lost to a trehalose-free medium. The uptake systems were present directly after growth on glucose, then decayed with a half-life of about 25 min but could be reactivated by aerobic incubation with trehalose, maltose, alpha-methyl-D-glucoside, glucose or ethanol. The uptake systems thus induced were different as revealed by competition experiments. At least one of the systems for trehalose uptake showed cooperative kinetics. Comparative anaysis with other disaccharides indicated the existence in Saccharomyces cerevisiae, after induction with trehalose, of at least four systems for the uptake of alpha-methyl-D-glucoside, four systems for maltose, together with the two for trehalose, variously shared by the sugars, the total of alpha-glucoside-transporting systems being five.


Ultrastructural changes in the cell wall of Candida albicans following cessation of growth and their possible relationship to the development of polyene resistance.

The ultrastructure of the wall of Candida albicans strain 6406 was examined in polyeneresistant organisms obtained by continued incubation after the cessation of growth. The walls of organisms harvested either during the exponential phase of growth or after 24 h starvation, when examined in situ, showed the typical layered appearance. After 72 h starvation, when the resistance to amphotericin B methyl ester (AME) was 60 times greater than that of exponentially growing organisms, both the periplasmic material and the distinct electron-dense layers were absent from the wall. At this stage there was no increase in the thickness of the wall. After 144 h starvation the thickness of the wall had increased from 143 +/-22 nm (exponential phase organisms) to 211+/-58 nm. If after 144 h starvation the organisms were incubated for 1 h in fresh nutrient medium they regained their sensitivity to AME and the wall regained the periplasmic material and its characteristic multilayered appearance. During the first 24 h starvation there was a considerable fall in the soluble glucan fraction, but on continued incubation there was little change in the relative proportions of the major carbohydrate constituents of the cell. Thin sections of purified walls isolated from organisms harvested either during exponential growth or after 144 h starvation were identical in appearance and characterized by the absence of the electrondense layers observed in sections of intact cells and by a reduction in thickness to 100+/-20nm.


Division and death rates of Salmonella typhimurium inside macrophages: use of penicillin as a probe.

In mouse peritoneal macrophages infected in vitro with Salmonella typhimurium the number of viable bacteria and the number of stainable bacteria detected by light microscopy both increased at similar rates with a doubling time of more than 1 h. Antibiotics were not present; instead extracellular bacteria were removed by frequently rinsing the cells. The bacterial doubling time in the same medium in the absence of macrophages was about 20 min. Penicillin added to macrophage monolayers rapidly entered the macrophages, reaching a diffusion equilibrium. The penicillin-induced bacterial death rate appeared to depend on the bacterial division rate as well as on the penicillin concentration. These properties of penicillin were used to monitor intracellular bacterial division and death rates. The results indicated that intracellular killing, with the disappearance of stainable bacteria, did not contribute to the extended doubling time in macrophages. It was concluded that the intracellular environment of the bacteria was probably growth inhibitory but not bactericidal.


The study of Escherichia coli proteases. Intracellular serine protease of E. coli-an analogue of bacillus proteases.

Two serine proteases in extracts of Escherichia coli grown to stationary phase were purified to homogeneity using affinity chromatography on gramicidin S-Sepharose 4B. One enzyme was closely related to, if not identical with, the 'trypsin-like' protease II of E. coli. The other was capable of cleaving the subtilisin chromogenic substrate N-carbobenzoxy-L-alanyl-L-alanyl-L-leucine-p-nitroanilide and resembled the intracellular serine proteases of Bacillus spp. The amino acid composition of this E. coli protease was similar to that of the Bacillus licheniformis enzyme. These data indicate a relationship between proteolytic enzymes of evolutionary distant Gram-negative Enterobacteriaceae and Gram-positive spore-forming Bacillus.


Sympathetic activity and transcendental meditation.

Ten male advanced meditators and ten male long-term meditators subjected themselves four times to slight physical exercise following a period of rest, meditation or reading. Daily urine excretions of catecholamines and VMA were determined in both groups. On the experimental days 4-hour urine specimens, one before and one after the experiments, were again collected for analysis. During the experiments blood pressure and heart rate were measured continuously and blood samples were taken for plasma catecholamine levels immediately before and after the physical exercise. Daily catecholamine and VMA excretions showed to be higher in advanced meditators. During the experiments the pattern of noradrenaline, adrenaline and VMA excretions were different in both groups, long-term meditators showing a higher adrenaline excretion after exercise. After the resting period there was in both groups a similar increase of plasma catecholamine levels during exercise. However, after meditation the advanced meditators showed a significant increase in plasma noradrenaline and no further increase in plasma noradrenaline level during the following physical exercise. Also after the reading period differences between both groups in plasma catecholamine levels during exercise could be observed. In advanced meditators heart rate reduction after meditation was about 9% and diastolic blood pressure was slightly raised. The preceding conditions of rest, meditation or reading had a significant different influence on the behaviour of heart rate and blood pressure during the following physical exercise and this pattern was different for both groups.


Cellular hypersensitivity to brain antigen in children of a family with hereditary ataxia.

Sensitisation to brain antigen was demonstrated in eight of 24 clinically normal first generation children in a family with hereditary ataxia. This ratio is consistent with that expected in a dominantly inherited condition. It suggests that immunological reactivity may precede the clinical expression of disease, with important implications for presymptomatic diagnosis and for pathogenesis of degenerative disease.


A computerized tomography-computer graphics approach to stereotaxic localization.

This paper describes the use of three-dimensional computer graphics to display structures visible in computerized tomography (CT) scans and to accurately determine optimum stereotaxic probe placement relative to those structures. A prototype Lucite stereotaxic frame designed for use in CT body scanners was fitted with a phantom consisting of small Lucite spheres representing intracranial tumors with diameters of 6 to 19 mm. A series of CT scans was obtained of the frame and phantom together. Edge outlines of the spheres were extracted from each scan in the series. A three-dimensional visual representation of the spheres was obtained by displaying their outlines from all CT scans. A superimposed visual simulation of the stereotaxic frame was adjusted interactively using several analog dials in order to simulate trajectory choice and probe depth before actual surgery. The frame settings and probe depth calculated by the graphical computer were then applied to the actual prototype frame in order to assess the accuracy of this combined CT-computer graphics approach to stereotaxic localization. The results of 22 such experiments and the implications for future clinical use of this new and precise localization technique are discussed.


Regional cerebral blood flow and oxygen utilization in superficial temporal-middle cerebral artery anastomosis patients: an exploratory definition of clinical problems.

Regional cerebral blood flow (rCBF) and regional cerebral oxygen utilization (rCMRO2) were measured before and after surgery in nine patients undergoing a superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis to bypass cerebrovascular lesions not amenable to extracranial operative procedures. The objective of these studies was to determine whether measurements of this type could provide objective criteria for surgery as well as assess the effect of surgery. The preliminary data, although limited, suggest that measurements of regional cerebral hemodynamics and metabolism in these patients before and after surgery provide valuable data upon which to develop criteria and assess results. For example, 1) a significant depression of rCBF and rCMRO2 in patients in whom a major cerebral infarction has not occurred, or 2) relative preservation of rCMRO2 despite depressed rCBF seem to be favorable indications for establishing a functioning STA-MCA anastomosis. In such patients, STA-MCA anastomosis can be followed by a return of rCBJ and rCMRO2 to virtually normal levels. Relatively normal rCBF and rCMRO2 in the presence of an occluded internal carotid artery in asymptomatic patients indicates satisfactory collateral circulation and is probably a contraindication to surgery.


Megavitamins and learning disorders: a controlled double-blind experiment.

The study investigated the effectiveness of large amounts of ascorbic acid, niacinamide, calcium pantothenate, and pyridoxine when added to a low carbohydrate-high protein diet with 20 learning disabled children. After a double-blind, 6-month period of treatment, the addition of vitamins to the diet failed to produce significant improvements when compared to the diet alone on a variety of intellectual, school achievement, perceptual, and behavioral, measures. Regardless of their group assignment, 18 children showed improvements on a parent-administered behavior checklist. However, without a diet-placebo control group, these gains may have been produced by parental enthusiasm or the children's maturation rather than dietary control. The children's urinary excretion of kryptopyrrole was unrelated to whether or not they showed pre-, post-test gains and, therefore, proved to be invalid as a screening test for "vitamin dependent (on pharmacologic doses) learning disorders."


Essential hormones as carcinogenic hazards.

Recently, the Occupational Safety and Health Administration (OSHA) proposed regulations regarding lists of environmental substances that allegedly pose potential occupational carcinogenic risk. Known carcinogens such as bis(chloromethyl) ether, along with natural substances such as estradiol, estriol, estrone, progesterone, tannic acid, maltose, and lactose, were included in the general OSHA list. Clear distinction between true hazards and essential endogenously formed biochemicals was not made. A major reappraisal of the OSHA list is essential. The revised document should indicate the conditions under which various classes of substances constitute human health hazards -- including dosage levels and routes of entry.


Toxicology of the sulfur oxides.

Continuing interest by OSHA-NIOSH and by EPA regarding the adequacy of current sulfur oxides standards has prompted a reappraisal of the available human and animal data. Results of animals studies were not considered to be useful in establishing the original air quality standards in 1970, even though there was good reason to consider them as a prime source of information. Considering the multitude of species tested, using every conceivable method of administration and range of doses, a fairly consistent pattern of effect has emerged. Further, the majority of the human clinical data and even the industrial data parallel and support the results found in the animal studies. However, neither the animal studies, the clinical investigations nor the industrial experiences agree with the recently reported community epidemiological studies that are currently receiving attention. It may well be that the toxicological data are correct in that there are no important long-term effects from exposure to the sulfur oxides. Certainly the laboratory studies, animal or human, do not support more stringent standards for either the occupational or the community environment.


Roentgenological detection of casting defects in cobalt-chromium alloy frameworks.

A method for non-destructive X-ray investigation of casting defects in cobalt-chromium prosthetic frameworks has been developed and tested. The attenuation properties of a cobalt-chromium alloy were studied. A dental X-ray machine with a tube voltage working at 70 kVp and a focus-film distance of 45-50 cm on dental ultraspeed film made it possible to detect defects representing 10% or less of the thickness of cobalt-chromium details with dimensions between 0.6 and 3.0 mm. The frequency and site of internal defects in sixty-six frameworks were investigated. Of the sixty-six frameworks only two were without roentgenologically visible defects. In the other sixty-four frameworks 294 pores or cracks were recorded. The defects were mostly situated in the saddles. Porosities occurred in 53% of the saddlebar regions. The results confirmed the need for a non-destructive routine test of prosthetic frameworks.


The prosthodontic rehabilitation of selected adults class III malocclusions.

In a previous paper (Murray 1978) some of the problems associated with currently employed preoperative assessment aids were discussed. Techniques were described for establishing the occlusal vertical dimension of occlusion, and support for the upper lip. The incorporation of these treatment planning aids in the prosthodontic rehabilitation of two adult cases, with class III malocclusions, is reported.


Clinical study of a heat-cured silicone soft lining material.

Thirty-seven mandibular dentures lined with Molloplast B silicone material were examined after they had been worn for 2-8 weeks and 6, 18 and 30 months. The denture wearers were also examined and interviewed. The colour was found to have become lighter in 46% and turned yellow or brown in 51%; the denture base had worn through in 24% and there was a failure on bond in 22%; no hardening of the material was noted; 24% of the dentures had broken. An unusual taste was reported by 22% and smell by 14% of the denture wearers; mucosal soreness was noted in 14%; denture stomatitis developed in 48%; hygiene was poor in 61% and fungal growth was traced in 81% of the dentures; 73% of the patients were satisfied with the soft lining.


Mucosal graft vestibuloplasty over a xenograft: report of case.

A case is described that demonstrates the use of DDBB to eliminate an anterior undercut in the augmentation in the edentulous mandible. Subsequent vestibular extension using a free mucosal graft was performed superficially to the xenograft bed. This material is extremely useful because it is biologically bonded to underlying bone and is not jeopardized by a second surgical procedure in the graft region.


Periodontal status of patients with reduced immunocapacity.

The periodontal status of patients with reduced immunocapacity was assessed. Gingival inflammation, periodontal destruction, and plaque accumulation were compared in three groups--renal transplant patients, dialysis patients, and normal individuals. The levels of all parameters were similar in the three groups indicating that immunosuppression does not affect the clinical appearance of periodontal disease when measurements are made in a single examination. In the transplant group, however, there is a lack of correlation between P.I. and G.I. and between P.I. and P.D.I., indicating a dissociation between plaque accumulation and the tissue response. Long-term longitudinal studies of periodontal disease in such patients are needed in order to obtain more meaningful information on the role of the immune system in affecting the rate of periodontal destruction. This study suggests that nonimmune mechanisms such as the direct effect of bacterial products on supporting tissues can account for at least some of the clinical manifestations of periodontal disease.


Damaging effects of toothbrush bristle end form on gingiva.

The ability of two different toothbrush bristle ends to produce traumatic gingival abrasion was assessed in a double blind study of 15 male and 15 female young adults. Brushing was performed in a circular fashion using a modified Bass Technique. An apparatus allowing continuous visual feedback of the average brushing force permitted a degree of standardization of the system. The upper left canine and bicuspid area had to be brushed for 30 seconds with cut toothbrush bristles (CP) and with round ended toothbrush bristles (RP) respectively. A two week interval separated the two brushing sessions. Traumatic lesions of the attached gingiva were stained with a disclosing solution, photographed and evaluated planimetrically. The "cut bristles" caused gingival abrasions 30% greater in extent than the round end bristles. The difference was not due to single brushing strokes accidentally greater for the "cut bristles". The size of the lesions was not sex dependent. To prevent gingival damage it is desirable to either round the bristles in production or to rid the bristle ends at least of sharp edges.


Tooth staining effects of an alexidine mouthwash.

The primary purpose of this study was to determine the amount of tooth staining produced by an alexidine mouthrinse. One hundred and eighty subjects rinsed twice daily for 1 month with either 15 ml of alexidine (0.035%) or a placebo solution. Prior to the study, the subjects were classified according to their smoking, coffee and tea drinking habits and these factors were subsequently considered in the analysis of the stain scores. Additionally, the effects on staining of a prior prophylaxis and the use of a fluoridated toothpaste during the study were determined. Upon termination of the study, subjects utilizing the active mouthrinse manifested a greater degree of staining than placebo users. The amount and intensity of the stain due to alexidine were not influenced (increased) by smoking, tea or coffee drinking habits. A prior prophylaxis did not reduce the staining propensity of alexidine users. The method of scoring developed can be used to assess the degree of tooth staining induced by antiplaque agents.


Long-term ocular changes in cystinosis: observations in renal transplant recipients.

Following renal transplantation in nephropathic cystinosis, an extension of retinopathy associated with a variety of subtle functional ocular abnormalities may occur. However, these abnormalities have not (except for photophobia) been of subjective significance to cystinotic patients. Our data, gathered from patients transplanted as long as nine years ago, indicate that cystinotic patients should not have renal transplant withheld because of the fear of subsequent progressive ocular deterioration.


Phenazines with two cationic side chains as potential antimalarials.

1,9-Phenazine-bis(dialkylaminocarboxamides) were prepared for screening as potential antimalarials. No significant activity against Plasmodium berghei was observed. The phenazine targets were prepared from 1,9-phenazinedicarboxylic acid by standard methods. The reaction between 1,9-phenazinedicarboxylic acid and thionyl chloride in the presence of dimethylformamide unexpectedly gave 4-chloro-1,9-phenazinedicarbonyl chloride.


The anterior point of reference.

Three points in space determine the position of the maxillary cast in an articulator. The dentist is most frequently concerned with selecting the posterior two of the three reference points. In addition, the dentist will, either consciously or unknowingly, select the anterior of these points of reference. This decision will affect the development of occlusion and esthetics. The dentist and the auxiliaries must share a common objective in using an anterior point of reference. Five commonly used anterior points of reference and the reasons for the use of each have been discussed.


Complete dentures using the TMJ articulator.

A method of recording mandibular movements in a stereographic recording and a method of registering these movements by molding the controls in an articulator are described. Mandibular registrations are made using impressions rather than stabilized trial denture bases. The TMJ articulator used in the technique complies with all of the requirements of an articulator for prosthodontic treatment as outlined by the Academy of Denture Prosthetics.


Structural changes for speech improvement in complete upper denture fabrication.

In the absence of any clearly identifiable pathologic condition, the prosthodontic patient demonstrating speech problems after insertion of complete dentures is having difficulty with loss of turbulence, because of the diminution of tactile location skills in speaking, or both. Potential aids to speech improvement are a nonanatomic papilla placed on the oral surface of the denture just posterior to the location of the incisive papilla, a transversely elongated rugae-like papilla at about the same location, a roughened region at that spot, or an identation sufficient for the patient's tongue to identify. The location and effectiveness of such structural changes can be planned and judged with the cooperation of a qualified speech pathologist.


The effect of various clasping systems on the mobility of abutment teeth for distal-extension removable partial dentures.

Three clasping systems were placed in five patients, and measurements of abutment tooth mobility were made. These data were compared to previously established baselines and statistically analyzed. The findings of the study are: 1. There was no difference in abutment tooth mobility during the 4-week test period with each of the three clasping systems. The important factor may have been the fit of the distal-extension denture base over the residual ridge, which provides the stability to prevent increases in abutment mobility. 2. Any mobility increases were in a buccal direction only, or toward the flexible retentive clasp arm. There was never any change in lingual mobility. 3. All five patients chose the I-bar retainer as the design of choice due to its increased resistance to dislodgment.  Periodic recall of distal-extension removable partial denture patients is mandatory to ensure proper stress distribution and prevent increases in abutment tooth mobility.


The relationship of pattern position to the flow of gold and casting completeness.

To minimize the possibility of incomplete casting due to improper pattern orientation relative to the sprue and direction of the casting arm motion, the following precautions should be taken. 1. Locate the pattern in the trailing half of the casting ring 90 to 135 degrees away from the sprue position. 2. Once the pattern is in the position described, locate it downward in the lower outer quarter of the trailing half of the casting ring and secure it in that position. 3. Mark the ring or sprue former so that the invested pattern can be oriented properly in the casting arm. 4. When using an electric casting machine, be certain that the pyrometer is correct. If in doubt, it is advisable to check the melt state of the gold before casting.


Fabrication of removable stone dies using cemented dowel pins.

Proper dowel pin placement in the working cast is important in the fabrication of a cast restoration. A technique is suggested whereby the dowel pin is orientated and cemented after the working cast has been separated from the impression. This procedure produces a working die that has a correctly positioned dowel pin, is stable, and can be repeatedly returned to its original relationship. A technique is suggested whereby the dowel pin is orientated and cemented after the working cast has been separated from the impression. This procedure produces a working die that has a correctly positioned dowel pin, is stable, and can be repeatedly returned to its original relationship.


A reassessment of the mandibular transverse horizontal axis therory.

1. Within the limits of accuracy imposed by individual operators, equipment, and patient variations, a single transverse horizontal axis can usually appear to be located. 2. Location of a kinematic axis is worthwhile clinical procedure to transfer an arc of rotation in the sagittal plane from the patient to an articulator. 3. Past experiments have been useful, but none have proved or disproved the presence of colinear or noncolinear condyle arcs. Only the arc of the rigid clutch and its associated mechanism is located. Such an apparent arc may result from the resolution of compound condylar movements. 4. The right angle-nonright angle concept is misleading and generally is not applicable to clinical procedures. 5. The anatomic asymmetries of the axis transfer procedure may result in cast dislocations that may produce undesirable alterations in esthetic tooth positions. 6. The single transverse horizontal axis as a fact in articulating instruments and as a theory in the human craniomandibular complex. 7. The terms "transverse horizontal mandibular axis" and "intercondylar axis" should not be confused or used as synonyms. The term "transverse horizontal mandibular axis" ("hinge axis") should be used instead of "condylar" or "intercondylar" axis.


Geometric analysis of tooth arrangement.

Based on the principles of solid geometry and projection geometry, a mathematical system can be used to indicate any positional change of tooth arrangement on a trial denture. To summarize: 1. When you move a tooth, you have to know whether you move the tooth toward the patient's left side or right side (x), upward or downward (y), anteriorly or posteriorly (z), and how many millimeters in each component dimension. If rotatory movements are involved, you must know whether the tooth rotates around the mesiodistal axis (+/-M), around the faciolingual axis (+/-F), or around the gingivo-occlusal axis (+/-G). You must know the degrees of rotation around each of the component axes and whether the movement is clockwise or counterclockwise. Most students will easily follow this systemic approach and readily understand the complexity of the problem.


Reinforced matrices for pin-amalgam restorations reduce microleakage.

The considerable decrease in microkeakage in the compound-reinforced restorations may be due to the tighter fit of the matrix band at the gingival wall of the preparation, which allows better condensation and marginal sealing of the restoration. The compound prevents lateral migration of the band during condensation pressures.


Temperature change caused by reducing pins in dentin.

Pin temperature increases (heat generation) was prevented by an air-water coolant. Pin height adjustment with an ultraspeed instrument using air-water coolant produces no potentially injurious heat generation.


A study of the relationship of the dental midline to the facial median line.

This report presents the results of an original investigation designed to determine (1) the prevalence in the natural dentition of a maxillary midline located in the exact middle of the mouth using the philtrum as the most reliable guide and (2) the percentage of people in whom the maxillary and mandibular midlines precisely coincide with each other. Results indicate that the midline is situated in the exact middle of the mouth in approximately 70% of people and that the maxillary and mandibular midlines fail to coincide in almost three fourths of the population.


Repair of porcelain-fused-to-metal restorations.

Three techniques have been described which may be used to repair many porcelain-fused-to-metal restorations. These techniques provide an avenue of repair for extensive porcelain-fused-to-metal restorations without remaking the entire prosthesis. The success of the overlay and pin-retained ceramo-metal repairs should be comparable to that of a newly constructed porcelain-fused-to-metal restoration. The composite resin bonded to porcelain repair technique will not have as favorable a prognosis, as composite resins are more subject to wear and are not color stable, and the chemical bond created with silance bonding agents is much weaker than the bond created when porcelain is fused to metal. Success of silance-bonded repairs should not be expected for periods longer than 2 to 3 years.


Examination of living Sertoli cells in normal and hypospermatogenic men.

The functional state of living Sertoli cells can be assessed by using transillumination and phase-contrast microscopy. In tissue from hypospermatogenic men the Sertoli cells contained more lipid droplets than in normal cases and sometimes whole degenerative cells.


Testis development in the vole, Microtus agrestis, subjected to long or short photoperiods from birth.

Voles exposed to long photoperiods (16L:8D) from birth became sexually mature at 40-45 days and remained so up to the end of the experiment at 6 months of age. In short photoperiods development was inhibited up to 60 days but the majority of males became sexually mature between 4 and 6 months of age.


Hysteroscopic removal of a Heyman radium capsule.

This case report demonstrates the use of the hysteroscope for the localization and removal of a missing Heyman radium capsule in a patient with endometrial carcinoma. There has been much recent interest in the use of the hysteroscope for therapeutic purposes in clinical gynecology. This case report emphasizes the value of this instrument in patient care.


Measuring the attainment of primary care.

Specification of the characteristics unique to primary care, as distinguished from secondary and tertiary care, has been difficult. Descriptions based upon the nature of problems actually seen by practitioners or those based upon the way in which patients come for care do not adequately distinguish primary care from nonprimary care. Definitions of primary care have stressed its first-contact aspects, coordinating features, comprehensiveness, and longitudinality. While these phenomena are adequate as gross descriptors, the inability to quantify them reduces their usefulness to planners and evaluators. Offered as a solution to this problem is a model which permits these descriptors to be defined as specific interrelationships among separate aspects of the structure (accessibility, range of services, identification of the eligible population, and continuity), process (utilization and problem recognition), and outcome of care.


The role of psychiatry in Western European medical education.

During 1976-77 the authors studied psychiatric education in Western Europe, visiting university centers in 10 countries. Medical education in various European countries has developed out of different traditions. The significance of these for the present educational systems are discussed and the differences from the U.S. curriculum clarified. Psychiatry until recently in Europe has been dominated by a phenomenological approach. It has not assumed the same importance in the curriculum as in the United States. However, since the student revolts of 1968, there have been major reforms in teaching, including changes in the role of psychiatry in medical education and increased attention to social and psychological factors in health and disease.


Stimulation of lymphocyte reactivity by a low molecular weight cutaneous antigen in patients with progressive systemic sclerosis (scleroderma).

A low molecular weight cutaneous antigen was found to stimulate the release of macrophage migration inhibition factor from circulating lymphocytes of patients with diffuse scleroderma. The antigen had a molecular weight of approximately 3,500 and contained RNA and polypeptides, but no hydroxyproline. Lymphocytes from patients with the CREST syndrome, rheumatoid arthritis, and from normal controls did not respond to the antigen. An immune response to this antigen may be a factor in the pathogenesis of diffuse scleroderma.


A unique pattern of toxic synthesis in pentitol catabolism: implications for evolution.

All of our Escherichia coli C mutants blocked in the first step of D-arabitol catabolism (D-arabitol dehydrogenase) became unable to grow in the presence of D-arabitol. We have shown that this sensitivity is eliminated by a defect in the second enzyme of the pathway (D-xylulokinase), leading to a pattern of toxicity and its relief which has not been previously reported. We have found a similar pattern of toxicity and its relief in the closely related ribitol pathway. The evolutionary significance of these findings is discussed.


Renal transplantation in Reye's syndrome: fate of the recipient--a case report.

A case is reported of a successful transplant of kidneys from a 15-month-old girl who died of complications of Reye's syndrome. The patient is well 28 months after the transplant and, despite treatment for 2 rejection episodes, there had been no increase in viral serologic titers nor evidence of the clinical viral syndrome. The literature on renal transplantation in Reye's syndrome as well as Reye's syndrome itself is reviewed. The world literature on this subject is sparse and this case is presented to give support and justification for the use of Reye's syndrome cadaver donors.


Treatment of solitary and bilateral renal carcinomas.

Recent experience with 7 patients, as well as a review of the literature, indicates that partial nephrectomy provides satisfactory treatment of solitary and bilateral renal adenocarcinomas. Patient survival seems to be dependent on the adequacy of tumor resection and not on the fate of the contralateral kidney. Total nephrectomy, dialysis and subsequent transplantation are viable alternatives when it is technically not possible to preserve adequate renal parenchyma.


Malignancy in uremia: dialysis versus transplantation.

The incidence of cancer was compared in 499 dialysis patients and 121 renal transplant recipients. De novo malignancy developed in 15 patients on chronic dialysis (3 per cent) and in 6 transplant recipients (4.9 per cent), a significant increase over the expected number in the age-matched general population. There was no difference in the incidence of cancer in uremic patients on dialysis or after transplantation. A total of 10 dialysis patients (67 per cent) and 1 transplant patient (16 per cent) died of cancer. Neoplasms in the dialysis patients were the common types of mesenchymal tumors, while superficial skin cancers were seen more frequently in the transplant recipients. The differences in tumor types accounted for the higher mortality rate from cancer in the dialysis patients and may reflect different patterns of immunosuppression in these 2 patient populations.