Time-delay Fizeau phase-conjugate interferometer

A time-delay Fizeau phase-conjugate interferometer is constructed by using a BaTiO(3) crystal in a degenerate four-wave-mixing configuration. The slow response time of BaTiO(3) is used to build a phase-conjugate mirror that functions as a holographic memory. An optical wave and its time-delayed version are stored inside the crystal sequentially while their phase-conjugate waves are generated simultaneously. Superposition of the two phase-conjugate waves produces an interferogram as a result of the relative phase change of the input waves. The simplicity and real-time operation of this technique lead to several advantages over the conventional holographic interferometry. The use of photorefractive crystal eliminates the darkroom process and reposition procedure. A higher accuracy can be achieved because the interfering waves are phase-conjugate waves. The principle of this technique is presented and the experimental results and its applications are discussed.

Detection of hepatitis B virus in plasma using flow cytometric analyses of polymerase chain reaction-amplified DNA incorporating digoxigenin-11-dUTP

Blood donations are routinely screened by multiple serologic assays for antigens/antibodies associated with infection by blood-borne viruses, including hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency viruses (HIV-1 and HIV-2), and human T-cell lymphotropic virus (HTLV-I and HTLV-II). A direct detection of these viruses would be more effective for the prevention of transfusion-transmitted infections than the indirect measurement of the variable host immune response to these agents. Because the polymerase chain reaction (PCR) for viral gene amplification offers the most sensitive and direct means of detecting viruses in blood, we have developed a nonisotopic PCR procedure for the detection of HBV, chosen as a prototype. The problems, common to previously described PCR methods, of nucleic acid extraction and inhibition of the PCR by plasma proteins were overcome by isolation of HBV from plasma by means of 450-microns polystyrene beads covalently coated with monoclonal antibody to the Pre-S1 region of the viral envelope protein. Detergent lysis and proteinase K digestion of the immunocaptured virions isolated from plasma released the HBV DNA. A modified PCR-amplification protocol, incorporating digoxigenin-labeled dUTP in the amplified gene products followed by hybridization with a specific biotinylated oligonucleotide probe bound to streptavidin-coated 2.8-microns magnetic beads, allowed flow cytometric analyses of HBV-specific PCR products by means of antibodies to digoxigenin labeled with fluorescein isothiocyanate. The endpoint serial dilutions of pedigreed human plasma samples containing chimpanzee infectious dose (CID50) of 10(7) for adw and CID50 of 10(7.5) for the ayw subtypes were compared in repeated testing of PCR products by our immunoreactive bead (PCR-IRB) assay. HBV DNA was consistently detected in a 5 x 10(-10) dilution of each sample. In testing 20 coded specimens of blood donors, with or without serologic markers of HBV infection, the PCR-IRB was specific and more sensitive than the PCR analyses by slot blot hybridization with radioactive probe. The PCR-IRB assay can be adapted for simultaneous detection of multiple blood-borne viruses by an automated flow cytometric analysis system.

The epidemiology of selenium deficiency in the etiological study of endemic diseases in China

The distribution of chemical elements in rocks and soils varies widely. Selenium is one of the elements that has remarkable regional variations in distribution and bioavailability. This paper reviews the epidemiology of selenium deficiency in China in connection with the etiology of human selenium-responsive diseases, the well-defined Keshan disease (KD) and the less-well-defined Kashin-Beck disease (KBD).

Malignant epithelioid hemangioendothelioma arising in an intramuscular lipoma

BACKGROUND

A malignant epithelioid hemangioendothelioma (EH) developed within a peripheral intramuscular lipoma. It was seen as a painful calf mass. At the time of biopsy and en bloc resection, lung metastases were observed.

METHODS

Radiologic, histologic, immunohistochemical, and ultrastructural features of the neoplasm are described, and the literature pertaining to EH is reviewed.

RESULTS

The features of this tumor permitted its classification as a malignant EH.

CONCLUSIONS

This case illustrates the potential for aggressive behavior in an EH, often considered to be a low-grade malignant neoplasm. Because such tumors can metastasize, they should be removed with wide margins whenever possible. This malignant neoplasm was located within a benign intramuscular lipoma, demonstrating the diagnostic problem that may exist in such a complex lesion.

Direct visualization of the dendritic and receptive fields of directionally selective retinal ganglion cells

Optical methods were used to locate the cell bodies of directionally selective ganglion cells in isolated rabbit retinas. These neurons detect the direction in which images move across the retinal surface and transmit that information to the brain. The receptive field of each identified cell was determined, after which the cell was injected with Lucifer yellow. An image of the receptive field border was then projected onto the fluorescent image of the dendrites, allowing precise comparison between them. The size of the receptive field matched closely the size of the dendritic arbor of that cell. This result restricts the types of convergence that can be postulated in modeling the mechanism of retinal directional selectivity.

Mutagenesis of the Glu-89 residue in human immunodeficiency virus type 1 (HIV-1) and HIV-2 reverse transcriptases: effects on nucleoside analog resistance

A Glu-89-->Gly alteration in the human immunodeficiency virus type 1 reverse transcriptase (RT) was previously shown to result in resistance to several dideoxynucleoside analogs and to phosphonoformic acid (PFA; foscarnet). This residue was altered to Ala, Val, Ser, Thr, Gln, Asp, Asn, or Lys, and the ddGTP and PFA sensitivities of the mutant RTs were measured. Replacements with Ala, Gly, Val, and Thr led to resistance to inhibition by ddGTP, while mutants with amino acid Ser, Gln, Asn, Asp, or Lys displayed only moderate or no resistance. A similar result was obtained with inhibition by PFA, except that the Asp-89 mutant also displayed resistance. Furthermore, the introduction of Glu-89-->Gly alteration into the RT of human immunodeficiency virus type 2 likewise rendered it resistant to both ddGTP and PFA.

Identification of an essential region for growth signal transduction in the cytoplasmic domain of the human interleukin-4 receptor

Interleukin-4 (IL-4) is a pleiotropic lymphokine which plays an important role in the immune system by regulating proliferation and differentiation of a wide variety of lymphoid and myeloid cells. These biological effects are manifested via binding of IL-4 to specific membrane-associated high affinity receptors. While the IL-4 receptor (IL-4R) cDNA expresses high affinity binding sites when transfected in COS7 cells, its intracellular domain lacks consensus motifs for known signal transducing molecules such as a tyrosine kinase. In this study, we use a DNA deletion approach to explore the mechanism of signal transduction utilized by the human IL-4R cDNA expressed in a murine pro-B cell line, Ba/F3 cells. Using this system, we have identified the critical region of the cytoplasmic domain of human IL-4R for human IL-4-induced transduction of a growth signal in these cells. Our data indicate that the critical region for signal transduction is located between amino acid residues 433-473 numbering from the carboxyl terminus. This region is highly conserved between mouse and human IL-4R but lacks homology with other cytokine receptors. Our studies additionally demonstrate that the cytoplasmic domain is not essential for forming high affinity IL-4-binding sites nor for ligand internalization.

[Biochemical and immunological characterization of desmosomal proteins]

Desmosmoes were dissolved by incubation at 100 degrees C for 30 minutes in lysis buffer containing 9.5 M urea. SDS-PAGE revealed seven high molecular weight (> 67 kd) bands and some keratins. Seven of these were considered to be major bands. Bands 1 and 2 with M(r) values of 250 kd and 215 kd, called desmoplakins I and II. Polypeptide bands 3, 4a 4b, 5 and 6 had M(r) values of 165kd, 130kd, 115kd, 83kd and 75kd, respectively. 2-2.5mg of Desmoplakin I was obtained by a preparative electrophoresis; the purity reached 93.1%. The isoelectric pH range was between 6.8 and 7.2, and the amino acid compositions displayed a relatively high content of glycine. It was found that McAb Desmoplakin I recognized specifically the 250kd antigenic band by immunoblotting.

Effects Of Reservoir Heterogeneities On Heavy Oil Recovery By Steam-Assisted Gravity Drainage

Abstract

Previous studies of the SAGD process have been based on homogeneous reservoir models. In this paper, new experiments are described which simulate heterogeneous reservoirs. These include reservoirs with thin sha1e layers and reservoirs containing horizontal layers of different permeabilities.

The results show that a short horizontal barrier does not affect the general performance greatly. A long horizontal barrier decreases the production rate but, in some configurations, not nearly as much as might be expected. It is observed that faster production is found when a higher permeability layer is above a lower permeability layer than when the conditions are reversed.

Introduction

The production of heavy oils by gravity drainage to a horizontal well with the continuous injection of steam above follows from the existing steam stimulation and steam flooding practices. The process has been recognized as steam-assisted gravity drainage (SAGD). Rapid development in this area is being encouraged by improved horizontal well drilling technology which allows more favourable economics. Butler et al.(2,3,4) carried out early experimental and theoretical studies on this area. Their theoretical predictions agreed well with the homogeneous reservoir model experiments.

No reservoir is completely homogeneous, and the degrees of heterogeneity can vary significantly, even within the same field. It is necessary that preliminary experiments be performed to study the effects of reservoir heterogeneities.

The research work presented here is limited to two types of reservoirs which are considered to be representative and close to the real field conditions:reservoirs with thin shale layers,reservoirs containing horizontal layers of different permeabilities.

Laboratory studies were conducted using a visual reservoir model saturated with Cold Lake bitumen. The steam injection pressure employed was 153 kPa. Two different well configurations have been investigated.. The first consisted of a vertical circulation steam injector which was perforated near the top of the formation with bitumen produced at the bottom; the second employed a similar configuration to the first, bur with steam introduced slightly above the production well at the base of the formation. Photographs were taken at specified time intervals and the temperature profile was recorded continuously to provide a means for comparisons and eventually for selecting an optimal well configuration for different reservoir conditions.

Experimental

The two-dimensional reservoir model is that which has been described by Butler et al.(1) only with minor modifications. The schematic experimental set-up is illustrated in Figure 1. The model was scaled to the field conditions by using the method described by Butler et a1(2). The scaling parameters are shown in Table 1. One hour for the model is equivalent to 1.5 years in the field. The vertical circulating steam injector(1) was employed to initiate the communication between the injection and production well. The injection well location was adjusted vertically to allow for different steam injection locations. Figures 2a and 2b show how this vertical steam injector works.

The porous materials used in the reservoir model were 2 mm and 3 mm glass beads. In order to obtain a uniformly random packing of the porous pack, the reservoir model was secured on a vibrating table.

[Selection of DSP points in second stage and their presentation]

The principal of selecting DSP points is discussed. Because social and economic development is not balance, developing level of health business and health situation of population are obvious varies in different areas of China. In order to ensure that health information from surveillance population can be used to infer health situation of national population, the feature of geographic, administrative areas and various health situation in different areas are considered. The principals of selecting DSP are: 1. To assure well-balance of geographic distribution of DSP. 2. To assure well-balance of distribution of DSP in different kind of areas, according to above 9 index, GNP, illiterate rate, birth rate, infant death rate, rough death rate, ratio of 0-14 years people to total people, ratio of about 65 years people to total people, ratio of labor in industry to total people, and ratio of labor in agriculture to total people. The way of select DSP is: Multistage stratified random sampling (PPS). Meanwhile in order to avoid systematic error, about 15% points which are no qualified were changed. Therefore whether data from DSP can be represented health level of population of whole nation has been tested. The conclusion is that the data from DSP can indeed do so.

Nonintegrin laminin receptors in the nervous system: evidence for lack of a relationship to P40

Laminins are extracellular matrix proteins that mediate their effects on cells through integrin and nonintegrin receptors. Two receptors of 67 and 110 kD that bind laminin with a high affinity (Kd approximately nM) have been reported in neural cells. Here, we discuss these and other nonintegrin laminin receptors that have been implicated in neural function. In addition, we report studies characterizing a 43 kD protein, (P40), immunologically related to the 67 kD laminin receptor, which may be involved in retinal development. In our studies, polyclonal antisera (anti-P-20-A) to a synthetic peptide derived from the sequence of a cDNA for a putative high-affinity laminin receptor (67 kD) detected a protein of 43 kD in immunoblots of adult rat retinas. Immunohistochemistry with this antiserum showed that the retinal immunoreactivity was predominantly localized in the ganglion cell layer of both adult chicken and rat retinas where it appeared to be intracellular. Retinal ganglion cells were shown to be immunoreactive by retrogradely labeling them from the superior colliculus with a lipophilic dye and subsequently with anti-P-20-A antisera. Consistent with the preferential localization of the P-20-A immunoreactivity in ganglion cells, there was a substantial decrease in the amounts of P40 on Western blots following optic nerve section and resulting retinal ganglion cell death. Screening of a rat (PC12 cell) cDNA library with the anti-P-20-A antiserum further confirmed the specificity of the antiserum for the rat homologue of P40. Rat P40 is 97% identical to the mouse and 87% identical to human P40 at the nucleic acid level and 98% at the protein level. Restriction mapping of the rather abundant positive clones in the library that cross-hybridized with a human cDNA probe for P40 indicated that the full-length cDNA of 1.2 kb was the major and perhaps the only cDNA in the library. In Northern blots of adult rat retina, these clones hybridized to a single 1.2-kb transcript. Electroblots of retinal homogenates probed with radioiodinated laminin demonstrated binding to a broad band at 110 kD, but none at 43 kD. Taken together these findings suggest that P40 may not be a laminin receptor and are in keeping with the hydrophilic composition of the protein, its intracellular localization, as well as other features predicted by its nucleic acid sequence.(ABSTRACT TRUNCATED AT 400 WORDS)

Corneal cell-matrix interactions: type VI collagen promotes adhesion and spreading of corneal fibroblasts

Type VI collagen is a nonfibrillar collagen present as a network throughout the chick secondary stroma. Immunolocalization of type VI collagen both in the chick corneal stroma and in other systems demonstrates that type VI collagen is present associated with cells and between striated fibrils. We hypothesize that type VI collagen may function in cell-matrix interactions important in corneal development. To examine this possibility, we have isolated and characterized bovine corneal type VI collagen and determined that the chain composition and morphology of type VI collagen isolated from cornea is similar to that isolated from other sources. The tissue form of type VI collagen was localized to filaments forming a network around fibrils and close to corneal fibroblasts. We then analyzed relative attachment and spreading on type VI collagen as compared to the other collagens present in the secondary stroma, and found that although corneal fibroblasts attach equally well to type VI and type I collagen, cells spread to a much greater extent on type VI collagen. Although corneal fibroblasts do have an RGD-dependent receptor which functions during adhesion to fibronectin, attachment to type VI collagen is RGD-independent unless the molecule is denatured. Blocking of the RGD-dependent receptor with soluble RGD peptides results in no change in attachment or spreading. These data imply a role for type VI collagen in cell-matrix interactions during corneal stroma development.

[Cause analysis of measles incidence in National Diseases Surveillance System in 1990]

This paper described the time and areas distribution of 875 measles cases in DSP in 1990 and discussed relationship between vaccination and measles cases. Through studying cases in several points with high morbidity, the authors found that there was no high immunization coverage. It must have been the first chance of measles incidence. Further more the immunization technics and cold chain were found unqualified, which were thought to be the second chance.

Microcarrier culture of fish cells and viruses in cell culture bioreactor

This article deals with the culture of grass carp (Ctenopharyngodon idellus) lip and embryo cells on Cytodex 3 and GT-2 microcarriers in a 1.5-L cell culture bioreactor to propagate grass carp hemorrhage virus. The cells and viruses were successfully cultivated at 26 degrees C, pH 7.0, and dissolved oxygen 40% of air saturation. The cell density achieved was as high as 7.4 x 10(6) cells/mL, and the virus titre reached 6.75 log LD50/0.5 mL from an initial 3.00 log LD50/0.5 mL. The results present broad prospects for fish virus vaccine production.

[Environmental and inheritive factors on large bowel cancer]

In order to clarify the influence of inherit and environmental factors on the large bowel cancer, a population-based case-control study involving 850 cases and 857 controls matched by age and sex, and a entailed family cancer history survey were carried out from September 1988 through August 1989. Multivariate analysis showed that less intake of crude fibre increased risk of the cancer whereas vegetables was negatively associated after controlling for some possible confounding factors. The intake of fat, protein and meat slightly raised the risk of the cancer. Univariate analysis showed that the history of large bowel cancer in first degree relatives had a remarkable risk (RR = 2.2, P less than 0.05), but adjusting environmental factors (especially dietary factors, e. g. fat, protein, crude fibre, calories ect.) the history had no close relationship with the cancer. The heritability of large bowel cancer was 16.78 +/- 6.20%.

Studies on avian spinal cord chimeras. I. Neurological and histological manifestations

Spinal cord chimeras were produced by replacing a small fragment of neural tube of a 2-day-old White Leghorn chicken embryo with a similar fragment from a Japanese quail embryo. The embryo mortality was 61%, and 72% of hatched birds were 'cripples' and had to be sacrificed within 5 days after hatching. Forty-nine chimeras, 10.9% of the total number of operated embryos, were alive for more than 3 weeks. For at least 17 days after hatching, all birds behaved like normal chicks, and the grey quail-like feathers were the only manifestations of their chimerism. Initial neurological symptoms of unsteady walking and drooping of the wings were noted in all birds except for 1 that died an accidental death before it became sick. Advanced symptoms characterized by paralysis of the legs forcing the bird to lie on its side were noted in 40 birds. The chimeras could be divided into two groups, each consisting of 24 birds. The short-survival (SS) chimeras of the first group became terminally ill and had to be sacrificed within 3 months. The long-survival (LS) chimeras of the second group showed more protracted disease, in that only 16 of them showed symptoms of the advanced disease, and the majority showed partial or complete recovery. Ten of the LS birds were kept alive for more than 8 months. Furthermore, many LS chimeras lost their grey feathers. The hallmarks of neurohistological manifestations were mononuclear cell infiltrates, demyelinization with preservation of axons and scar formation. These lesions were restricted to the quail fragment of the spinal cord except for 2 birds in which distant cellular infiltrates were observed. Direct immunofluorescence tests for chicken IgG were positive in spinal cords of most SS chimeras but only of some LS chimeras.

Studies on avian spinal cord chimeras. II. Immune response of the chicken host to the graft of quail tissue

A previous study described clinical and pathological manifestations observed in 49 chimeras produced by replacing a small fragment of the neural tube of a chicken embryo by a similar fragment from a Japanese quail embryo. Predominant antibodies in sera of these birds were directed against xenogeneic antigens which are devoid of organ specificity and which are present in quail tissues but absent from chicken tissues. Mixed agglutination test with quail cell monolayers detected such antibodies in sera of all chimeras tested. In most instances, positive reactions were observed already in the 4th week after hatching; they persisted in all birds throughout the observation period of up to 8 months. Some of the detected antibodies were directed against saline-nonextractable surface antigens of quail cells. Enzyme immunoassay with quail organ extracts, agglutination of quail tissue particles, and indirect immunofluorescence test with quail organ sections were positive with sera of many, but not all, chimeras. CNS-specific antibodies, apparently autoantibodies, were detected in serum samples of only one chimera, using enzyme immunoassay with extract of chicken brain and indirect immunofluorescence test with sections of chicken spinal cord. Eluates from lesional spinal cord contained antibodies to non-organ-specific quail antigens but not to CNS-specific antigens. Cerebrospinal fluids of many chimeras had antibodies to quail antigens, but no evidence for antibody formation within the CNS was obtained. Cell-mediated immunity could be demonstrated in all chimeras tested by means of lymphocyte proliferation test after stimulation by quail organ extract. It was concluded that pathological events in the studied chimeras have been most likely mediated primarily by humoral immune responses to non-organ-specific quail antigens.

Free radical yields from the homolysis of peroxynitrous acid

A recent study reports discordant results for maximal free-radical yields from the decomposition of peroxynitrous acid using different assay reagents and a puzzling decrease (to zero) of the radical yields with increasing pH. An assay method using 2,2,'azino-bis(3-ethyl-benzthiazoline sulphonate) (ABTS) has been tested using stopped-flow kinetic studies, and the results imply that the assay is satisfactory when [HOONO] much greater than [-OONO] but that reactions involving peroxynitrite anion interfere at higher pH. Evidence is presented that peroxynitrite was an interfering species in the earlier studies.

[Restriction fragment length polymorphisms of chloroplast DNA and the intergenic spacer of rRNA gene in cultivated barley of China]

A sample of 80 accessions collected from several major barley growing areas in China was assayed for restriction fragment length polymorphisms at two regions of the chloroplast DNA and the intergenic spacer of the ribosomal RNA gene (rDNA). The results showed that the spacer length was highly polymorphic and 8 spacer length variants constituting 8 phenotypes were observed in this sample. It is also clear that the spacer length variants and the phenotypes were differentially distributed in different geographical regions, probably due to adaptation of the genotypes to the local environments. We did not detect variation in the two chloroplast fragments, indicating that the variability of chloroplast DNA is low in cultivated barley.

[Isolation of desmosomes: a marker for epithelial tumors]

A simple method is reported for the isolation of desmosomes. The fresh noncornified layers of cow nose epidermis were immersed in 0.1 mol/L citric acid-sodium citrate buffer (pH 2.3, containing 0.5 mmol/L PMSF), and then treated with homogenization and discontinuous sucrose density gradient centrifugation. Desmosomes were located at the 50-56% sucrose interface. Electron microscopy revealed that the characteristic desmosome structure was well preserved, and that a few intermediate filament bundles attached to desmosome plaque were removed by the solubilizing action of the buffer. Approximate 100 mg desmosomes (dry weight) were got from 20g wet noncornified layers of epidermic tissue.

New method of one-step rainbow holography of diffuse three-dimensional objects with no slit

A new method of one-step rainbow holography of diffuse three-dimensional objects with no slit is proposed. Diffuse three-dimensional objects are translated uniformly along the direction of the y(0) axis. A coherent plane wave illuminates the objects and its propagation direction is situated on the x(0)-z(0) plane. As a result of this process, a sinc function modulating the complex amplitude distribution of the objects is produced in the back focal plane of the lens. Therefore, rainbow holography is achieved. Theoretical analysis and some experimental results are presented.