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Biomedical subjects

D J Anderson

Publications and source records attributed to D J Anderson.

At least 289 records · Page 16Linked to original sources
PubMed1990

Nucleotide sequence of the Methylobacterium extorquens AM1 moxF and moxJ genes involved in methanol oxidation.

The nucleotide sequence has been determined for two genes involved in methanol oxidation in the facultative methylotroph, Methylobacterium extorquens AM1. The two genes are moxF, encoding the 66-kDa subunit of the methanol dehydrogenase and moxJ, located immediately downstream from moxF, which encodes a 30-kDa protein with unknown function. This information completes the sequence of the 5.86-kb XhoI-SalI fragment containing the moxFJGI region in M. extorquens AM1, and the structure of this gene cluster is presented. Evidence is presented that moxJ is also present in Paracoccus denitrificans. The aa sequence of MoxJ has provided little information concerning its function, but it does appear to contain a signal sequence suggesting a periplasmic location.

Alcohol Oxidoreductases↗
PubMed1990

Effect of nerve growth factor and fibroblast growth factor on SCG10 and c-fos expression and neurite outgrowth in protein kinase C-depleted PC12 cells.

The role of protein kinase C (PKC) in mediating nerve growth factor (NGF) or basic fibroblast growth factor (bFGF)-stimulated SCG10 and c-fos expression as well as neurite outgrowth was studied in PC12 cells. Activators of PKC such as phorbol 12-myristate 13-acetate (PMA) or 1-oleoyl 2-acetyl glycerol mimicked the stimulatory effect of NGF and bFGF on SCG10 mRNA levels. Induction involved a protein synthesis-dependent mechanism and was maximal within 12-24 h of exposure. Chronic treatment of the cells with PMA for up to 8 days resulted in a substantial decrease (approximately 90%) in total PKC activity in the continued presence of PMA. PKC depletion did not affect NGF- or bFGF-stimulated SCG10 mRNA induction and bFGF-stimulated c-fos mRNA induction. However, NGF-stimulated c-fos mRNA induction was attenuated. In addition, induction of neurite outgrowth was not abolished in PKC-depleted cells. The results imply that PKC is not involved in NGF- and bFGF-stimulated SCG10 mRNA induction and neurite outgrowth. Furthermore, while the effect of bFGF on c-fos mRNA induction is PKC-independent, that of NGF is mediated by PKC-dependent and -independent pathways.

Adrenal Gland Neoplasms↗
PubMed1990

Induction of class II major histocompatibility complex antigen expression in human granulosa cells by interferon gamma: a potential mechanism contributing to autoimmune ovarian failure.

We investigated the possibility that major histocompatibility complex (MHC) class II antigens and interferon gamma, a product of activated T lymphocytes, play a role in human autoimmune oophoritis. MHC class II molecules initiate immune responses by presenting antigens to T-helper lymphocytes; interferon gamma can induce class II antigen expression at ectopic sites and has been implicated in the cause of various autoimmune disorders. We studied the expression of class II MHC antigens in ovaries from normal women of reproductive-age and from women with premature autoimmune ovarian failure. Immunoperoxidase technique applied to tissue sections of nine normal human ovaries revealed class II MHC antigen expression only on occasional cells of macrophage morphology; granulosa cells were negative regardless of stage of follicular maturation. In contrast, extensive and intense class II antigen expression was observed in granulosa cells in ovarian biopsy sections from four patients with premature autoimmune ovarian failure. Immunofluorescence and radioimmunoassay techniques used to detect and quantitate MHC antigens revealed that class II antigen expression could be induced and class I MHC antigen expression was enhanced in granulosa cell cultures after the addition of interferon gamma. These data provide evidence that autoimmune oophoritis is associated with ectopic expression of MHC class II antigens by ovarian granulosa cells, and that this phenomenon can be induced by the immunologic cytokine interferon gamma.

Adult↗
PubMed1990

Localization of leukocytes and cytokines in chorionic villi of normal placentas and complete hydatidiform moles.

Monoclonal antibodies were used to localize and characterize leukocytes and cytokines in chorionic villi of normal placenta and complete mole. OKT4a reacted with Hofbauer cells in first-, second-, and third-trimester placentas. HLA-DR was expressed on second- and third-trimester placental Hofbauer cells but was not detected in the first trimester. The cytokines, gamma-interferon, granulocyte-macrophage colony-stimulating factor, interleukin-1 alpha, and tumor necrosis factor alpha, were all detectable on Hofbauer cells in first-, second-, and third-trimester placentas. None of the tested cytokine antibodies reacted with cellular constituents in complete molar chorionic villi. The absence of cytokine-positive cells in molar chorionic villi may be related to the hyperplastic and unregulated growth of molar villous trophoblast.

Antibodies, Monoclonal↗
PubMed1990

A v-myc-immortalized sympathoadrenal progenitor cell line in which neuronal differentiation is initiated by FGF but not NGF.

Sympathetic neurons differentiate from a developmentally restricted progenitor cell in the neural crest-derived sympathoadrenal lineage. We have isolated these progenitors by fluorescence-activated cell sorting and immortalized them using a v-myc-containing retrovirus. The complement of antigenic markers expressed by these lines suggests that they have retained many of the properties of their normal counterparts. These lines initiate neuronal differentiation in response to basic FGF, but not to NGF, and do not contain NGF receptor mRNA. In NGF plus FGF, however, a small percentage of the cells differentiate to NGF-dependent postmitotic neurons. Furthermore, an induction of NGF receptor mRNA can be observed in response to FGF. Thus, the development of sympathetic neurons may involve a relay, in which FGF both initiates differentiation and induces the NGF receptor, which in turn controls further maturation and survival.

Animals↗
PubMed1990

A cell type-preferred silencer element that controls the neural-specific expression of the SCG10 gene.

SCG10 is a growth-associated protein that is expressed early in the development of neuronal derivatives of the neural crest. We describe here the isolation of the SCG10 chromosomal gene and the identification of regulatory regions that control its expression. The SCG10 transcription unit spans approximately 40 kb. Like other neural-specific genes, SCG10 contains multiple transcription initiation sites. The gene contains a constitutive enhancer-like element in the promoter-proximal region and a silencer located farther upstream. This silencer preferentially suppresses the activity of the enhancer in nonneuronal cells. Furthermore, the silencer is able to confer such preferential suppression upon a heterologous promoter in an orientation-independent manner. These data suggest that the expression of SCG10 in neuronal cells depends predominantly upon specific derepression.

Animals↗
PubMed1990

Analysis of SCG10 gene expression in transgenic mice reveals that neural specificity is achieved through selective derepression.

SCG10 is a neural-specific, growth-associated protein that is broadly expressed in the embryonic central and peripheral nervous systems. Transgenic mice harboring a chimeric gene containing 4 kb of SCG10 5' flanking DNA fused to the bacterial CAT gene exhibit expression in brain but not in nonneuronal tissues. A low level of expression is detected in adrenal gland as well, consistent with the behavior of endogenous SCG10. Such a transgene is also activated at the same relative stage of embryonic development as its endogenous counterpart. Deletion of the 5'-most 3.7 kb of SCG10 sequence yields deregulated expression of the transgene in numerous nonneuronal tissues, although expression remains highest in brain. In contrast to other tissue-specific genes, therefore, the specificity of SCG10 expression appears to be achieved predominantly through selective repression in nonneuronal tissues.

Adrenal Glands↗
PubMed1990

Differential diagnosis of immature germ cells in semen utilizing monoclonal antibody MHS-10 to the intra-acrosomal antigen SP-10.

The monoclonal antibody (mAb) MHS-10 (IgG1) is a mouse antihuman sperm antibody which recognizes a polymorphic sperm protein, (SP-10), which has previously been localized within the acrosomal matrix and the acrosomal membranes. The SP-10 antigen has been shown to be sperm-specific and is not found in somatic tissues. It is stage specific, having been immunohistologically localized to Golgi phase spermatids and all subsequent phases of spermiogenesis. In the present study, acetone-dried smears from washed human semen containing significant numbers of round cells were probed with mAb MHS-10. Monoclonal antibody-labeled cells were visualized by a standard streptavidin-biotin immunoperoxidase method using a light microscope. The MHS-10 mAb immunoreacted with mature sperm and with a subset of round cells diagnosed as developing spermatids, which had been sloughed off from the testis at varying stages of acrosome formation. To rule out possible cross-reactivity of the mAb with leukocytes in semen, a leukocyte surface marker (anti-HLe-1) was used in conjunction with MHS-10. Round cell populations staining with MHS-10 did not stain with anti-HLe-1. The mAb MHS-10 is thus a promising probe for the identification and quantitation of immature germ cells in human semen.

Antibodies, Monoclonal↗
PubMed1990

Digital mobile radiography.

A storage phosphor digital imaging system has been used to perform virtually all of an increasing number of mobile (portable) projectional roentgenographic examinations in a busy hospital. Approximately 130 such studies are done per day, of which about 110 are chest examinations. The processing unit suffices to keep pace with peak activity in the radiology department. This technique has decreased the repeat rate for portable anteroposterior chest radiographic examinations from 4.5% to less than 1% and has resulted in an even more dramatic reduction in the rate for lateral or decubitus chest examinations as well as for studies of the abdomen and those done in the operating room. The diagnostic accuracy and confidence level achieved in interpreting the complementary pair of digital images has been equivalent to or has exceeded that obtained with conventional mobile analog film-screen radiographs.

Equipment Design↗
PubMed1990

Die-away kinetic analysis of the capacity of epilithic and planktonic bacteria from clean and polluted river water to biodegrade sodium dodecyl sulfate.

The capacities of epilithic and planktonic river bacterial populations to degrade sodium dodecyl sulfate (SDS) in samples taken at two times during 1987 from one clean and four polluted sites in a South Wales river were estimated in die-away tests under simulated environmental conditions. There was a relatively slow disappearance of SDS in die-away tests for both planktonic and epilithic populations taken from the clean source site, as compared with those taken from the downstream polluted sites, for which the rate of biodegradation was accelerated, sometimes after an apparent initial lag period. The kinetic components contributing to the die-away curves were quantified by nonlinear regression analysis in which the experimental data were fitted to a variety of possible kinetic models. All samples except for one from the polluted sites best fitted a model which describes the biodegradation of SDS at concentrations well below its K(m) by bacteria whose growth is exponential and unaffected by the addition of a test substrate. Each sample from the clean source site fitted a different model, but there was generally little or no growth on endogenous carbon. A consideration of the numerical values of constants derived from the modeling of epilithic and planktonic populations from polluted sites indicated clearly that the biodegradative capacity of epilithic bacterial populations towards SDS is more stable than that of planktonic bacterial populations.

Journal Article↗
PubMed1990

Evoked vertex and inferior colliculus responses to electrical stimulation of the cochlear nucleus.

Evoked potentials were recorded from the vertex and the inferior colliculus in guinea pigs in response to electrical stimulation of the cochlear nucleus complex. The stimuli consisted of 80-microseconds biphasic pulses, ranging from 20 to 5,000 microA. The effect of electrode location (nerve root area, surface, and in-depth dorsal cochlear nucleus) on the evoked response was assessed by measuring amplitudes, latencies, and thresholds as a function of stimulating current levels. Stimulation of the nerve root area resulted in the shortest latencies, the largest amplitudes, and the lowest thresholds, whereas the surface of the dorsal cochlear nucleus was the least effective stimulating site.

Amplifiers, Electronic↗
PubMed1990

Viral pneumonia in recipients of solid organ transplants.

Viral pulmonary infections are a major cause of morbidity and mortality in solid organ transplant recipients. The herpes viruses-cytomegalovirus, herpes simplex virus, varicella zoster virus, and Epstein-Barr virus--cause most of the viral infections in this population. Respiratory syncytial virus, adenovirus, and human immunodeficiency virus also cause pneumonitis in the transplant recipient. Differences in the clinical and laboratory presentation of pneumonitis due to the various viral agents can provide clues to the etiology. However, definitive diagnosis requires laboratory identification of the virus or appropriate serologic changes. With cytomegalovirus, herpes simplex virus, Epstein-Barr virus, and adenovirus, one must take care to distinguish between asymptomatic shedding of the virus and disease produced by the virus. Advances in diagnostic techniques such as rapid antigen detection, nucleic acid hybridization, and gene amplification may allow an earlier diagnosis of viral pneumonia. Advances in risk reduction with appropriate pairing of donors and recipients, improved immunosuppressive regimens, vaccination, and prophylactic administration of antiviral agents may reduce the incidence of viral infection. Finally, advances in anti-viral therapy have made possible the successful treatment of pneumonia due to some of the viral agents.

Adenoviridae Infections↗
PubMed1990

Immunological mechanisms in recurrent spontaneous abortion.

The acceptance and maintenance of pregnancy remains a biological mystery. The conceptus expresses paternal and embryonic antigens that are foreign to its maternal host yet is not always immunologically rejected. In this chapter we have presented a review of protective immunologic mechanisms possibly responsible for the maintenance of pregnancy, as well as a summary of current data suggesting immunologic mechanisms responsible for pregnancy wastage. Major rapid advances in understanding immunoreproduction should occur over the next several years due to major advances in the rapidly expanding field of immunology. It is now possible to perform in depth studies of immunoregulatory mechanisms. Numerous biochemical mediators of immunological responses have been defined and mass produced for use in research. These mediators have enabled the definition of cellular and humoral interactions within the immune system, and between the immune system and reproductive tissues. Monoclonal antibodies have also been produced that identify many of these mediators and leukocyte markers associated with immune function. It is now possible using these new immunological reagents to probe the immune mechanisms and immunoregulatory events responsible for the success and failure of reproduction. Systematic approaches utilizing these techniques are and will continue to contribute significantly to a further understanding of the immunological mechanisms involved in recurrent spontaneous abortion, which is prerequisite for developing truly effective treatment modalities.

Abortion, Habitual↗
PubMed1990

Cell-mediated immunity and inflammatory processes in male infertility.

Considerable evidence indicates that white blood cell concentrations are often elevated in semen of infertility patients, and that white blood cell products can affect sperm function in vitro. Furthermore, recent studies indicate that leukocytospermic semen samples exhibit poor motility characteristics and impaired ability to function in sperm penetration assays. We believe that the identification and quantification of white blood cells in semen should be an integral component of every semen analysis. If properly diagnosed, a significant number of infertility patients with leukocytospermia may benefit from antibiotic, antiviral, or anti-inflammatory drug treatments. Further studies should be directed at better defining the role of bacteria, viruses and other pathogens in leukocytospermia, and further understanding the effects of WBC products on sperm function.

Genitalia, Male↗
PubMed1990

Liver- and bone-derived isoenzymes of alkaline phosphatase in serum as determined by high-performance affinity chromatography.

To separate liver and bone alkaline phosphatase (ALP) isoenzymes in human serum, we used high-performance affinity chromatography (HPAC) on a column of wheat-germ lectin conjugated to 7-microns-diameter silica particles and an eluent containing N-acetyl-D-glucosamine (NAG). On-line spectrophotometric detection of ALP involved pumping diethanolamine-buffered p-nitrophenyl phosphate solution post-column. Bone and liver isoenzymes could be separated into two peaks with only 10% overlap when an exponential gradient was used. A linear-step gradient separated 80.9% of liver ALP and 91.6% of bone ALP in two distinct peaks. True bone and liver ALP peak areas for the linear-step gradient were determined by using correction factors, because each peak contained a co-eluted portion of the other ALP isoenzyme. The detection limit improved 10-fold over those of other techniques for ALP isoenzymes, owing to the relatively large sample that could be applied to the column. Correlation with a urea-inactivation procedure was reasonable for patients' serum samples (r = 0.98 and 0.79 for liver ALP and bone ALP, respectively).

Alkaline Phosphatase↗