Showing papers by "National Institutes of Health published in 1985"
Journal Article•
3,913 citations
TL;DR: An algorithm was developed which facilitates the search for similarities between newly determined amino acid sequences and sequences already available in databases and increases sensitivity by giving high scores to those amino acid replacements which occur frequently in evolution.
Abstract: An algorithm was developed which facilitates the search for similarities between newly determined amino acid sequences and sequences already available in databases. Because of the algorithm's efficiency on many microcomputers, sensitive protein database searches may now become a routine procedure for molecular biologists. The method efficiently identifies regions of similar sequence and then scores the aligned identical and differing residues in those regions by means of an amino acid replacability matrix. This matrix increases sensitivity by giving high scores to those amino acid replacements which occur frequently in evolution. The algorithm has been implemented in a computer program designed to search protein databases very rapidly. For example, comparison of a 200-amino-acid sequence to the 500,000 residues in the National Biomedical Research Foundation library would take less than 2 minutes on a minicomputer, and less than 10 minutes on a microcomputer (IBM PC).
3,902 citations
TL;DR: In this article, a new mixing scheme based on the MLEV-16 composite pulse decoupling cycle (II) was proposed, which is less sensitive to pulse imperfections and provides net magnetization transfer over a substantial bandwidth with only limited rf power.
3,552 citations
TL;DR: Preliminary results of the systemic administration of autologous lymphokine-activated killer (LAK) cells and the recombinant-derived lymphokin interleukin-2 to patients with advanced cancer are described, based on animal models in which this regimen mediated the regression of established pulmonary and hepatic metastases from a variety of murine tumors in several strains of mice.
Abstract: We describe here the preliminary results of the systemic administration of autologous lymphokine-activated killer (LAK) cells and the recombinant-derived lymphokine interleukin-2 to patients with advanced cancer This regimen was based on animal models in which the systemic administration of LAK cells plus interleukin-2 mediated the regression of established pulmonary and hepatic metastases from a variety of murine tumors in several strains of mice We treated 25 patients with metastatic cancer in whom standard therapy had failed Patients received both 18 to 184 X 10(10) autologous LAK cells, generated from lymphocytes obtained through multiple leukaphereses, and up to 90 doses of interleukin-2 Objective regression of cancer (more than 50 per cent of volume) was observed in 11 of the 25 patients: complete tumor regression occurred in one patient with metastatic melanoma and has been sustained for up to 10 months after therapy, and partial responses occurred in nine patients with pulmonary or hepatic metastases from melanoma, colon cancer, or renal-cell cancer and in one patient with a primary unresectable lung adenocarcinoma Severe fluid retention was the major side effect of therapy, although all side effects resolved after interleukin-2 administration was stopped Further development of this approach and additional patient follow-up are required before conclusions about its therapeutic value can be drawn
2,511 citations
TL;DR: The complete nucleotide sequence of two human T-cell leukaemia type III (HTLV-III) proviral DNAs each have four long open reading frames, the first two corresponding to the gag and pol genes.
Abstract: The complete nucleotide sequence of two human T-cell leukaemia type III (HTLV-III) proviral DNAs each have four long open reading frames, the first two corresponding to the gag and pol genes. The fourth open reading frame encodes two functional polypeptides, a large precursor of the major envelope glycoprotein and a smaller protein derived from the 3′-terminus long open reading frame analogous to the long open reading frame (lor) product of HTLV-I and -II.
2,358 citations
TL;DR: The purpose of the meeting was to identify the most important scientific research opportunities and the crucial clinical and technical issues that influence the progress of research on the diagnosis of AD.
Abstract: Early and accurate diagnosis of Alzheimer's disease (AD) has a major impact on the progress of research on dementia. To address the problems involved in diagnosing AD in its earliest stages, the National Institute on Aging, the American Association of Retired Persons, the National Institute of Neurological and Communicative Disorders and Stroke, and the National Institute of Mental Health jointly sponsored a workshop for planning research. The purpose of the meeting was to identify the most important scientific research opportunities and the crucial clinical and technical issues that influence the progress of research on the diagnosis of AD. The 37 participants included some of the most knowledgeable and eminent scientists and physicians actively involved in the study of AD. The participants were divided among six panels representing the disciplines of neurochemistry, neuropathology, neuroradiology, neurology, neuropsychology, and psychiatry. Within each of the panels, participants discussed specific areas of research requiring further
2,351 citations
TL;DR: Chromosome 18-specific DNA probes for the areas flanking the breakpoints also detected RNA transcripts 6 kilobases in length in various cell types, and the gene coding for these transcript seems to be interrupted in most cases of follicular lymphomas carrying the t(14;18) chromosomal translocation.
Abstract: Recombinant DNA probes were cloned for the areas flanking the breakpoint on chromosome 18 in cells from a patient with acute lymphocytic leukemia of the B-cell type; cells of this line carry the t(14;18) chromosomal translocation. Two of the probes detected DNA rearrangements in approximately 60 percent of the cases of follicular lymphoma screened. In follicular lymphoma, most of the breakpoints in band q21 of chromosome 18 were clustered within a short stretch of DNA, approximately 2.1 kilobases in length. Chromosome 18-specific DNA probes for the areas flanking the breakpoints also detected RNA transcripts 6 kilobases in length in various cell types. The gene coding for these transcript (the bcl-2 gene) seems to be interrupted in most cases of follicular lymphomas carrying the t(14;18) chromosomal translocation.
1,854 citations
TL;DR: The antiviral effects of a thymidine analogue,3'-azido-3'-deoxythymidine (BW A509U), which, as a triphosphate, inhibits the reverse transcriptase of HTLV-III/LAV, and the in vitro immune functions of normal T cells remain basically intact.
Abstract: The acquired immune deficiency syndrome (AIDS) is thought to result from infection of T cells by a pathogenic human retrovirus, human T-lymphotropic virus type III (HTLV-III) or lymphadenopathy-associated virus (LAV). In this report, we describe the antiviral effects of a thymidine analogue,3'-azido-3'-deoxythymidine (BW A509U), which, as a triphosphate, inhibits the reverse transcriptase of HTLV-III/LAV. This agent blocks the expression of the p24 gag protein of HTLV-III/LAV in H9 cells following exposure to virus. The drug also inhibits the cytopathic effect of HTLV-IIIB (a virus derived from a pool of American patients) and HTLV-III/RF-II (an isolate obtained from a Haitian patient that differs by about 20% in the amino acid sequence of the envelope gene from several isolates of HTLV-III/LAV, including HTLV-IIIB, analyzed so far). 3'-Azido-3'-deoxythymidine also completely blocks viral replication as assessed by reverse transcriptase production in normal human peripheral blood mononuclear cells exposed to HTLV-IIIB. Finally, at concentrations of 3'-azido-3'-deoxythymidine that block the in vitro infectivity and cytopathic effect of HTLV-IIIB, the in vitro immune functions of normal T cells remain basically intact.
1,782 citations
TL;DR: The cDNA sequence indicates that the 112-amino acid monomeric form of the natural TGF-β homodimer is derived proteolytically from a much longer precursor polypeptide which may be secreted.
Abstract: The partial amino-acid sequence of purified human transforming growth factor-beta (TGF-beta) was used to identify a series of cDNA clones encoding the protein. The cDNA sequence indicates that the 112-amino acid monomeric form of the natural TGF-beta homodimer is derived proteolytically from a much longer precursor polypeptide which may be secreted. TGF-beta messenger RNA is synthesized in various normal and transformed cells.
1,716 citations
TL;DR: It is found that RM is often much less than R, therefore, the number of recombination events may be greatly under-estimated in a parsimonious reconstruction of the history of a sample.
Abstract: Some statistical properties of samples of DNA sequences are studied under an infinite-site neutral model with recombination. The two quantities of interest are R , the number of recombination events in the history of a sample of sequences, and R M , the number of recombination events that can be parsimoniously inferred from a sample of sequences. Formulas are derived for the mean and variance of R . In contrast to R, R M can be determined from the sample. Since no formulas are known for the mean and variance of R M , they are estimated with Monte Carlo simulations. It is found that R M is often much less than R , therefore, the number of recombination events may be greatly under-estimated in a parsimonious reconstruction of the history of a sample. The statistic R M can be used to estimate the product of the recombination rate and the population size or, if the recombination rate is known, to estimate the population size. To illustrate this, DNA sequences from the Adh region of Drosophila melanogaster are used to estimate the effective population size of this species.
1,635 citations
TL;DR: General equations are derived that can be used to analyze tissue uptake data when the blood–plasma concentration of the test substance cannot be easily measured and for situations when trapping of theTest substance is incomplete and for a combination of these two conditions.
Abstract: The method of graphical analysis for the evaluation of sequential data (e.g., tissue and blood concentrations over time) in which the test substance is irreversibly trapped in the system has been expanded. A simpler derivation of the original analysis is presented. General equations are derived that can be used to analyze tissue uptake data when the blood–plasma concentration of the test substance cannot be easily measured. In addition, general equations are derived for situations when trapping of the test substance is incomplete and for a combination of these two conditions. These derivations are independent of the actual configuration of the compartmental system being analyzed and show what information can be obtained for the period when the reversible compartments are in effective steady state with the blood. This approach is also shown to result in equations with at least one less nonlinear term than those derived from direct compartmental analysis. Specific applications of these equations are illustr...
TL;DR: In this paper, the authors proposed a new method for measuring homonuclear NOE effects under spin-locked conditions, which they referred to as rotatingframe Overhauser enhancement spectroscopy (ROESY) since this name suggests a similarity with the closely related 2D NOESY experiment.
TL;DR: The ability of cancer cells to produce and to respond to their own growth factors (autocrine secretion) has become a central concept linking oncogene and growth factor research.
Abstract: The ability of cancer cells to produce and to respond to their own growth factors (autocrine secretion) has become a central concept linking oncogene and growth factor research. Oncogenes confer growth factor autonomy on cells not only by coding directly for autocrine peptide growth factors or their receptors, but also by amplifying the mitogenic signals generated by a growth factor at its receptor. Antagonists of positive autocrine growth factors can inhibit growth of cancer cells in experimental animals. Recently identified negative autocrine growth factors might themselves control aberrant cell growth.
TL;DR: It is demonstrated that a monoclonal antibody to bombesin binds to the C-terminal region of BLPs, blocks the binding of the hormone to cellular receptors and inhibits the clonal growth of SCLC in vitro and the growth ofSCLC xenografts in vivo.
Abstract: The autocrine hypothesis proposes that a cell produces and secretes a hormone-like substance that can interact with specific membrane receptors on its surface to induce effects such as proliferation. Thus, a cancer cell could act to stimulate its own growth. Bombesin and bombesin-like peptides (BLPs) such as gastrin-releasing peptide (GRP) cause various physiological responses in mammals, including stimulation of proliferation of 3T3 mouse fibroblasts and normal human bronchial epithelial cells in vitro and induction of gastrin cell hyperplasia and increased pancreatic DNA content in vivo in rats. Human small-cell lung cancer (SCLC) cell lines produce and secrete BLPs and can express a single class of high-affinity receptors for BLPs. Exogenously added BLPs can also stimulate the clonal growth and DNA synthesis of SCLC in vitro. These findings suggest that BLPs function as autocrine growth factors for this tumour. One way to test this hypothesis is to interrupt the function of the endogenously produced BLPs. Here, we demonstrate that a monoclonal antibody to bombesin binds to the C-terminal region of BLPs, blocks the binding of the hormone to cellular receptors and inhibits the clonal growth of SCLC in vitro and the growth of SCLC xenografts in vivo. These results demonstrate that BLPs can function as autocrine growth factors for human SCLC.
TL;DR: The t(14;18)(q32;q21) chromosomal translocation present in over 60% of human follicular lymphomas is characterized and an unexpected rearrangement of an Ig heavy-chain gene is exploited to clone the chromosomal breakpoint.
TL;DR: The practice and theoretical basis of pain measurement is reviewed and critically examined in the areas of animal research, human subjects laboratory investigation and clinical study, and subjective report procedures are evaluated in human laboratory and clinical areas.
Abstract: The practice and theoretical basis of pain measurement is reviewed and critically examined in the areas of animal research, human subjects laboratory investigation and clinical study. The advantages and limitations of both physiological and behavioral methods are discussed in each area, and subjective report procedures are evaluated in human laboratory and clinical areas. The need for procedures that bridge these areas is emphasized and specific issues are identified. Progress in the technology of pain measurement over recent decades is reviewed and directions for future work are suggested.
TL;DR: It is concluded that the t(14;18) chromosome translocation is the result of a mistake during the process of VDJ joining at the pre-B-cell stage of differentiation.
Abstract: In this study, the joining sequences between chromosomes 14 and 18 on the 14q+ chromosomes of a patient with pre-B-cell leukemia and four patients with follicular lymphoma carrying a t(14;18) chromosome translocation were analyzed. In each case, the involved segment of chromosome 18 has recombined with the immunoglobulin heavy-chain joining segment (JH) on chromosome 14. The sites of the recombination on chromosome 14 are located close to the 5' end of the involved JH segment, where the diversity (D) regions are rearranged with the JH segments in the production of active heavy-chain genes. As extraneous nucleotides (N regions) were observed at joining sites and specific signal-like sequences were detected on chromosome 18 in close proximity to the breakpoints, it is concluded that the t(14;18) chromosome translocation is the result of a mistake during the process of VDJ joining at the pre-B-cell stage of differentiation. The putative recombinase joins separated DNA segments on two different chromosomes instead of joining separated segments on the same chromosome, causing a t(14;18) chromosome translocation in the involved B cells.
Journal Article•
TL;DR: Using a chemically defined medium containing hydrocortisone, insulin, transferrin, 17 beta-estradiol and selenium, with or without serum supplementation, continuous cell lines can be established from 72% of all fresh biopsy specimens of small cell lung cancer containing tumor cells.
Abstract: Using a chemically defined medium containing hydrocortisone, insulin, transferrin, 17 beta-estradiol and selenium, with or without serum supplementation (2.5% v/v), continuous cell lines can be established from 72% of all fresh biopsy specimens of small cell lung cancer (SCLC) containing tumor cells. No differences were observed in the rate of establishing cell lines from newly diagnosed untreated patients, or from patients who have relapsed from prior therapy, or from a variety of different organ sites. Biochemical characterization of 50 SCLC cell lines for the expression of L-dopa decarboxylase; bombesin-like immunoreactivity; neuron-specific enolase, and the brain isozyme of creatine kinase, revealed that SCLC cell lines can be subdivided into two distinct classes: classic SCLC cell lines (35 lines), which express elevated levels of all four biomarkers; and variant SCLC cell lines (15 lines) which have undetectable levels of L-dopa-decarboxylase and bombesin-like immunoreactivity, but continue to express neuron-specific enolase and the brain isozyme of creatine kinase. The presence of the latter two markers distinguishes variant lines fron non-SCLC cell lines. In addition, four distinct classes were identified morphologically. The biomedical differences among established SCLC cell lines may account for the differences in response rates to cytotoxic therapy observed in newly diagnosed SCLC patients. A prospective study of biomarker characterization of SCLC tumors will determine if clinical differences exist between classic and variant SCLC tumors.
TL;DR: The relations among culture, conscientiousness, openness, and intelligence are discussed, and it is concluded that mental ability is a separate factor, though related to openness to experience.
Abstract: Research on the dimensions of personality represented in the English language has repeatedly led to the identification of five factors (Norman, 1963). An alternative classification of personality traits, based on analyses of standardized questionnaires, is provided by the NEO (Neuroticism, Extraversion, Openness) model (Costa & McCrae, 1980b). In this study we examined the correspondence between these two systems in order to evaluate their comprehensiveness as models of personality. A sample of 498 men and women, participants in a longitudinal study of aging, completed an instrument containing 80 adjective pairs, which included 40 pairs proposed by Goldberg to measure the five dimensions. Neuroticism and extraversion factors from these items showed substantial correlations with corresponding NEO Inventory scales; however, analyses that included psychometric measures of intelligence suggested that the fifth factor in the Norman structure should be reconceptualized as openness to experience. Convergent correlations above .50 with spouse ratings on the NEO Inventory that were made three years earlier confirmed these relations across time, instrument, and source of data. We discuss the relations among culture, conscientiousness, openness, and intelligence, and we conclude that mental ability is a separate factor, though related to openness to experience.
TL;DR: Brains from 15 individuals with AIDS and encephalopathy were examined by Southern analysis and in situ hybridization for the presence of human T-cell leukemia (lymphotropic) virus type III (HTLV-III), the virus believed to be the causative agent of AIDS.
Abstract: Unexplained debilitating dementia or encephalopathy occurs frequently in adults and children with the acquired immune deficiency syndrome (AIDS). Brains from 15 individuals with AIDS and encephalopathy were examined by Southern analysis and in situ hybridization for the presence of human T-cell leukemia (lymphotropic) virus type III (HTLV-III), the virus believed to be the causative agent of AIDS. HTLV-III DNA was detected in the brains of five patients, and viral-specific RNA was detected in four of these. In view of these findings and the recent demonstration of morphologic and genetic relatedness between HTLV-III and visna virus, a lentivirus that causes a chronic degenerative neurologic disease in sheep, HTLV-III should be evaluated further as a possible cause of AIDS encephalopathy.
TL;DR: The extreme genetic monomorphism, especially at the major histocompatibility complex, and the apparent hypersensitivity of the cheetah to a viral pathogen may be related, provide a biological basis for understanding the adaptive significance of abundant genetic variation in outbred mammalian species.
Abstract: A population genetic survey of over 200 structural loci previously revealed that the South African cheetah (Acinonyx jubatus jubatus) has an extreme paucity of genetic variability, probably as a consequence of a severe population bottleneck in its recent past. The genetic monomorphism of the species is here extended to the major histocompatibility complex, since 14 reciprocal skin grafts between unrelated cheetahs were accepted. The apparent consequences of such genetic uniformity to the species include (i) great difficulty in captive breeding, (ii) a high degree of juvenile mortality in captivity and in the wild, and (iii) a high frequency of spermatozoal abnormalities in ejaculates. The species vulnerability of the cheetah was demonstrated by an epizootic of coronavirus-associated feline infectious peritonitis in an Oregon breeding colony in 1983. Exposure and spread of the coronavirus, which has a very low morbidity in domestic cats (approximately 1 percent), has decimated a heretofore productive and healthy captive population. The extreme genetic monomorphism, especially at the major histocompatibility complex, and the apparent hypersensitivity of the cheetah to a viral pathogen may be related, and provide a biological basis for understanding the adaptive significance of abundant genetic variation in outbred mammalian species.
TL;DR: Discriminant analysis can be used to precisely classify membrane proteins as integral or peripheral and to estimate the odds that the classification is correct, and it is found that discrimination between integral and peripheral membrane proteins can be achieved with 99% reliability.
TL;DR: It appears that the mechanism of the antitumor effect of recombinant IL-2 administered systemically is via the generation of LAK cells in vivo, although this hypothesis remains to be proven.
Abstract: Incubation of resting lymphoid cells with recombinant interleukin 2 (IL-2) in vitro leads to the generation of lymphokine activated killer (LAK) cells capable of lysing fresh tumor cell suspensions in short-term chromium-release assays. Our previous studies (7) have demonstrated that the injection of LAK cells plus low doses of recombinant IL-2 were capable of inhibiting the growth of pulmonary metastases. We have now explored the ability of high doses of recombinant IL-2, administered systemically, to generate LAK cells in vivo, and to mediate antitumor effects directly. Administration of increasing doses of recombinant IL-2 intraperitoneally resulted in the generation of LAK cells in the spleens of recipient mice. Doses of 100,000 U recombinant IL-2 administered intraperitoneally approximately every 8 h for 5 d were capable of dramatically inhibiting established 3-d pulmonary metastases from the MCA-105 and MCA-106 syngeneic sarcomas and the syngeneic B16 melanoma in C57BL/6 mice. Grossly visible metastases present at 10 d after tumor injection also underwent regression following IL-2 therapy. Surprisingly, established 10 d pulmonary metastases were more susceptible to the effects of IL-2 than were the smaller 3 d pulmonary metastases. All antitumor effects of the systemic administration of recombinant IL-2 were eliminated if mice received prior treatment with 500 rad total body irradiation. The administration of high doses of recombinant IL-2 was also capable of inhibiting the growth of 3-d established subcutaneous tumors from the MCA-105 sarcoma, and of mediating the inhibition of growth and regression of established palpable subcutaneous MCA-105 sarcomas. Lymphocytes, which appeared morphologically to be activated, were present at the site of regressing tumor, and it appears that the mechanism of the antitumor effect of recombinant IL-2 administered systemically is via the generation of LAK cells in vivo, although this hypothesis remains to be proven. The ready availability of high doses of recombinant human IL-2, and the demonstration of antitumor effects seen in animal models have led us to the initiation of the clinical trials of recombinant IL-2 in humans.
TL;DR: The production of a monoclonal antibody to BSF-1 is reported, its use in characterizing and functional studies demonstrating that this molecule is distinct from IL-1, IL-2 and IL-3 are demonstrated.
Abstract: B-cell stimulatory factor-1 (BSF-1)1, formerly designated B-cell growth factor, is a T-cell-derived factor required for entry into the S phase of the cell cycle by B cells stimulated with low concentrations of anti-IgM antibodies2–5. BSF-1 acts directly on resting B cells to prepare them to synthesize DNA more promptly on subsequent exposure to competent stimuli6,7 and to strikingly enhance their expression of class II molecules of the major his-tocompatibility complex8,9. Previous studies have shown that murine BSF-1 can be separated physically from interleukin-2 (IL-2) and that the molecule has an apparent relative molecular mass (Mr) of ∼ 15,000 and pI values of 6.4–6.7 and 7.4 (ref. 10). Here, we report the production of a monoclonal antibody to BSF-1, its use in characterizing BSF-1, and functional studies demonstrating that this molecule is distinct from IL-1, IL-2 and IL-3.
TL;DR: Human bone cell cultures established by maintaining collagenase-treated, bone fragments in low Ca++ medium exhibited a high level of alkaline phosphatase activity and produced a significant increase in intracellular cAMP when exposed to the 1–34 fragment of human parathyroid hormone.
Abstract: Human bone cell cultures were established by maintaining collagenase-treated, bone fragments in low Ca++ medium. The resulting cell cultures exhibited a high level of alkaline phosphatase activity and produced a significant increase in intracellular cAMP when exposed to the 1-34 fragment of human parathyroid hormone. With continued culture, the cells formed a thick, extracellular matrix that mineralized when cultures were provided daily with normal levels of calcium, fresh ascorbic acid (50 μg/ml) and 10 mM β-glycerol phosphate. Biosynthetically, these cells produced type I collagen (without any type III collagen), and the bone-specific protein, osteonectin. In addition, the cells produced sulfated macromolecules electrophoretically identical to those positively identified as the bone proteoglycan in parallel cultures of fetal bovine bone cells. This technique provides a useful system for the study of osteoblast metabolismin vitro.
TL;DR: The localization of the GA-like immunoreactivity in the locus coeruleus suggests a partial coexistence with catecholaminergic neurons as well as a possible involvement of theGA-like peptide in a neuroregulatory role.
TL;DR: Findings suggest an enlarging role for myc-related genes in human lung cancer and provide evidence for the concept of a myc family of proto-oncogenes, which is associated with cytogenetic abnormalities in certain human tumours.
Abstract: Altered structure and regulation of the c-myc proto-oncogene have been associated with a variety of human tumours and derivative cell lines, including Burkitt's lymphoma, promyelocytic leukaemia and small cell lung cancer (SCLC). The N-myc gene, first detected by its homology to the second exon of the c-myc gene, is amplified and/or expressed in tumours or cell lines derived from neuroblastoma, retinoblastoma and SCLC. Here we describe a third myc-related gene (L-myc) cloned from SCLC DNA with homology to a small region of both the c-myc and N-myc genes. Human genomic DNA shows an EcoRI restriction fragment length polymorphism (RFLP) of L-myc defined by two alleles (10.0- and 6.6-kilobase (kb) EcoRI fragments), neither associated disproportionately with SCLC. Mouse and hamster DNAs exhibit a 12-kb EcoRI L-myc homologue, which indicates conservation of the gene in mammals. Gene mapping studies assign L-myc to human chromosome region 1p32, a location distinct from that of either c-myc or N-myc but associated with cytogenetic abnormalities in certain human tumours. This L-myc sequence is amplified 10-20-fold in four SCLC cell line DNAs and in one SCLC tumour specimen taken directly from a patient. Either the 10.0- or 6.6-kb allele can be amplified and in heterozygotes only one of the two alleles was amplified in any SCLC genome. SCLC cell lines with amplified L-myc sequences express L-myc-derived transcripts not seen in SCLC with amplified c-myc or N-myc genes. In addition, some SCLCs without amplification also express L-myc-related transcripts. Together, these findings suggest an enlarging role for myc-related genes in human lung cancer and provide evidence for the concept of a myc family of proto-oncogenes.
TL;DR: It is reported that in the case of RA-induced differentiation of neuroblastoma cell lines, a decreased level of expression is detected within 6 h of treatment and precedes both cell-cycle changes and morphological differentiation.
Abstract: Proto-oncogenes may be important in the cellular processes central for the growth and differentiation of normal cells. N-myc is a DNA sequence which shares limited homology to the proto-oncogene c-myc and has been found to be amplified in both primary tissue and cell lines from neuroblastoma, a childhood tumour of neuroectodermal origin. Differentiation of this embryonal tumour is of clinical importance, since occasional tumours have been noted to differentiate in vivo to benign ganglioneuroma. In vitro, many human neuroblastoma cell lines can be induced to differentiate morphologically and biochemically by a variety of agents. Retinoic acid (RA), an analogue of vitamin A, has been shown to inhibit neuroblastoma cell growth and clonability in soft agar, and to induce extensive neurite outgrowth. Therefore we examined the relationship of N-myc expression to the in vitro differentiation of these cells. We report here that in the case of RA-induced differentiation, a decreased level of expression is detected within 6 h of treatment and precedes both cell-cycle changes and morphological differentiation.
TL;DR: It is hypothesized that gp160 and gp120 represent the major species of virus-encoded envelope gene products for HTLV-III.
Abstract: Antibodies from the serum of patients with the acquired immune deficiency syndrome (AIDS) or with the AIDS-related complex and from the serum of seropositive healthy homosexuals, recognize two major glycoproteins in cells infected with human T-cell lymphotropic virus type III (HTLV III). These glycoproteins, gp160 and gp120, are encoded by the 2.5-kilobase open reading frame located in the 3' end of the HTLV-III genome, as determined by amino terminus sequence analysis of the radiolabeled forms of these proteins. It is hypothesized that gp160 and gp120 represent the major species of virus-encoded envelope gene products for HTLV-III.
TL;DR: The widespread cortical targets of MD neurons together with evidence for multiple thalamic inputs to prefrontal areas support a revision of the classical hodological definition of prefrontal cortex as the exclusive cortical recipient of MD projections.
Abstract: The frontal lobe projections of the mediodorsal (MD) nucleus of the thalamus were examined in rhesus monkey by transport of retrograde markers injected into one of nine cytoarchitectonic regions (Walker's areas 6, 8A, 9, 10, 11, 12, 13, 46, and Brodmann's area 4) located in the rostral third of the cerebrum. Each area of prefrontal, premotor, or motor cortex injected was found to receive a topographically unique thalamic input from clusters of cells in specific subdivisions within MD. All of the prefrontal areas examined also receive topographically organized inputs from other thalamic nuclei including, most prominently, the ventral anterior (VA) and medial pulvinar nuclei. Conversely, and in agreement with previous findings, MD projects to areas of the frontal lobe beyond the traditional borders of prefrontal cortex, such as the anterior cingulate and supplementary motor cortex. The topography of thalamocortical neurons revealed in coronal sections through VA, MD, and pulvinar is circumferential. In the medial part of MD, for example, thalamocortical neurons shift from a dorsal to a ventral position for cortical targets lying medial to lateral along the ventral surface of the lobe; neurons in the lateral MD move from a ventral to a dorsal position, for cortical areas situated lateral to medial on the convexity of the hemisphere. The aggregate evidence for topographic specificity is supported further by experiments in which different fluorescent dyes were placed in multiple areas of the frontal lobe in each of three cases. The results show that very few, if any, thalamic neurons project to more than one area of cortex. The widespread cortical targets of MD neurons together with evidence for multiple thalamic inputs to prefrontal areas support a revision of the classical hodological definition of prefrontal cortex as the exclusive cortical recipient of MD projections. Rather, the prefrontal cortex is defined by multiple specific relationships with the thalamus.