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Biomedical subjects

M Green

Publications and source records attributed to M Green.

At least 775 records · Page 43Linked to original sources
PubMed1978

An endodeoxyribonuclease of human KB cells. Purification and properties of the enzyme.

An endodeoxyribonuclease has been purified 750-fold from human KB cells. The purified endonuclease requires Mg2+ for maximum activity: Mn2+ was less than half as active and Ca2+ inhibited the reaction. The optimum pH is 8.8 in Tris-HCl and the optimum buffer concentration is 10 mM. KCl (and NaCl), --SH-reacting reagents, and tRNA strongly inhibit the reaction. An apparent molecular weight of 54,000 was determined by sedimentation in a glycerol gradient. The purified endonuclease cleaved native, double-stranded adenovirus 2 DNA, and the reaction proceeded stepwise during the initial stage of degradation by cleavage of the DNA substrate in half, then in half again, etc. At longer digestion times, single strand scissions were detected. RNA was not a substrate for the enzyme. Poly(dG) . poly(dC) was susceptible but poly(dA) . poly(dT) was resistant to degradation. Hydrolysis of adenovirus 2 DNA yielded double-stranded polynucleotides containing 5'-phosphoryl and 3'-hydroxyl termini with short, single-stranded regions presumably at the ends. More than 50% of the product of a limit digest had a chain length greater than 35 to 40 nucleotides. Analysis of the 5' and 3' end groups of the digestion products indicated a preference for the site of the enzymatic cleavage; thymidylic acid residues were present at the 5' end and deoxyguanosine residues at the 3' end, each with a frequency of 40 to 50%.

Cell Line↗
PubMed1978

An evaluation of the tuberculosis agglutination test.

The tuberculosis agglutination titre as described by Nicholls (1975) was measured without prior knowledge of the diagnosis in 27 patients with open pulmonary tuberculosis, 100 patients with other diseases and 14 control patients with no apparent disease. Reproducibility of the test, as judged by repeat estimations on split samples, was poor. When attempting to distinguish between the disease categories the test gave 29% false negatives in patients with tuberculosis and 52% false positives in patients with other disease. Therefore the tuberculosis agglutination titre cannot be recommended for use in distinguishing tuberculosis from other conditions.

Agglutination Tests↗
PubMed1978

Muscle activity during chest wall restriction and positive pressure breathing in man.

The effects of sustained constriction of the rib cage (RCC), constriction of the abdomen (AC) and of breathing against a positive pressure of 10 cms of water (PPB) were studied in four normal subjects with moderate constant hypercapnia. Intercostal electrical activity (Eic) was measured by implanted wire electrodes and diaphragmatic electrical activity (Edia) by oesophageal electrodes. There was no fixed relation between Edia and VT. VT was unaltered during AC and RCC: Edia was unaltered during AC but increased during RCC. The response to PPB without constriction varied: three subjects increased end-expiratory VL with increase in Edia and inspiratory Eic. One subject initially, and one subject after training, maintained end-expiratory VL constant with no change in Edia and an increase in expiratory Eic. When PPB was applied during AC and RCC there was an increase in Edia proportional to end-expiratory lung volume. The overall response to distortion was determined by voluntary choice, but muscle electrical activity reflected chest wall configuration: when the diaphragm was shorter and at a mechanical disadvantage its electrical activity increased. This was compatible with a reflex with afferent information from diaphragm tendon organ and muscle spindle receptors.

Action Potentials↗
PubMed1978

Analysis of human tumors and human malignant cell lines for BK virus-specific DNA sequences.

Most humans in the United States have been infected with BK virus (BKV), a human papovavirus. Because BKV has oncogenic properties, we have investigated whether it may be a cause of human cancer. Basic principles of tumor virology imply that BKV-induced tumors should contain BKV DNA sequences. Therefore, we assayed (by molecular hybridization) DNA from human tumors and malignant cell lines for BKV DNA, using BKV [(32)P]DNA as probe. The BKV [(32)P]DNA was labeled in vitro (nick translation) to specific activities of 1 to 2 x 10(8) cpm/mug. The BKV DNA used to prepare our probes had the properties expected of authentic BKV genomes, including density of superhelical DNA, sedimentation velocity in alkaline and neutral sucrose gradients, production of one fragment by endonuclease EcoRI cleavage and four fragments by endonuclease Hin II + III cleavage and reassociation properties. From these studies we conclude that our BKV probes hybridized well, and represented bona fide BKV DNA. Using three different BKV [(32)P]DNA probes, i.e., from three distinct plaque isolates, we have analyzed DNA from BKV-transformed cells, normal human tissues, and a large number of human tumors. All human DNAs (cell lines, normal tissues, tumors) hybridized 5% with BKV DNA. Hybridization analysis of BKV-transformed hamster cell DNA indicated 5-6 copies of at least 88% of the BKV genome per cell. No BKV DNA sequences were detected (above the normal 5% hybridization to all human DNAs) in the following normal human tissues: 10 kidney (BKV is usually isolated from urine), 3 spleen, 13 lung, 23 colon, 2 rectum, 1 ileum, and 1 skin. No BKV-specific DNA was found in 166 tumors, including 5 carcinomas (Ca) of stomach, 3 Ca small intestine, 26 Ca colon, 9 Ca rectum, 31 Ca lung, 9 adenocarcinomas and 5 oat cell carcinomas of lung, 17 melanomas, 5 Ca prostate, 4 Ca bladder, 6 Wilms tumors, 4 hypernephromas, 15 Ca kidney, 7 brain tumors, 5 Hodgkin lymphomas, 10 lymphomas (immunosuppressed patients have a high incidence of lymphomas), 2 reticulum cell sarcomas (spleen), and 3 skin tumors. We have also analyzed 7 human malignant cell lines (melanoma, lung, rhabdomyosarcoma, and glioblastomas), including several clones of a lung melanoma line; no BKV DNA sequences were detected. Because our probes could detect one copy of BKV DNA if only 10% of the cells were tumor cells, our results are very strong evidence that the tumors we analyzed did not have a BKV etiology. The tumors we tested represent about 50% of all cancers in the United States; there is no evidence that BKV is involved in the etiology of these types of tumors.

BK Virus↗
PubMed1978

Enhanced infectivity of adenovirus type 2 DNA and a DNA-protein complex.

The infectivity of adenovirus type 2 DNA and a DNA-protein complex was studied in 293 cells, a human embryonic kidney cell line transformed by sheared adenovirus type 5 DNA, and in human KB cells. Adenovirus type 2 DNA was more infectious (up to about 40-fold) in 293 cells than in KB cells, whereas a DNA-protein complex (prepared by a rapid procedure) had about the same infectivity in both cell lines. These data may mean that a factor present in 293 cells (perhaps a viral-coded protein) enhances the infectivity of free viral DNA. The infectivity of DNA and the DNA-protein complex was increased up to fivefold by brief treatment of cell monolayers with 25% dimethyl sulfoxide after transfection. Under these conditions, (i) the infectivity of native adenovirus type 2 DNA ranged from 400 to 1,300 PFU/microgram of DNA in 293 cells and from about 9 to 14 PFU/microgram of DNA in KB cells, and (ii) the infectivity of the DNA-protein complex was 6 X 10(3)to 2 X 10(4) PFU/microgram in 293 cells and 1.4 X 10(4) to 1.6 X 10(4) PFU/microgram in KB cells.

Adenoviruses, Human↗
PubMed1978

Evidence for an adenovirus type 2-coded early glycoprotein.

We have identified an adenovirus type 2 (Ad2)-induced early glycopolypeptide with an apparent molecular weight of 20,000 to 21,000 (20/21K), as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The 20/21K polypeptide could be labeled in vivo with [(3)H]glucosamine. [(35)S]methionine- and [(3)H]-glucosamine-labeled 20/21K polypeptides bound to concanavalin A-Sepharose columns and were eluted with 0.2 M methyl-alpha-d-mannoside. The pulse-labeled polypeptide appeared as a sharp band with an apparent molecular weight of 21K, but after a chase it converted to multiple bands with an average molecular weight of 20K. This variability in electrophoretic mobility is consistent with glycosylation or deglycosylation of the 20/21K polypeptide. Analysis of the pulse and pulse-chase-labeled forms by using partial proteolysis indicated that the polypeptides were highly related chemically, but not identical. Most of the 20/21K polypeptide is localized in the cytoplasm fraction of infected cells lysed by Nonidet P-40. The 20/21K polypeptide and a 44K polypeptide, labeled with [(35)S]methionine or [(3)H]glucosamine in Ad2-infected human cells, were precipitated by a rat antiserum against an Ad2-transformed rat cell line (T2C4), but not by antisera against three other Ad2-transformed rat cell lines, or by serum from nonimmune rats. The partial proteolysis patterns of the 20/21K and the 44K polypeptides were indistinguishable, indicating that the two polypeptides are highly related, and suggesting that the 44K polypeptide might be a dimer of the 20/21K polypeptide. The 20/21K polypeptide was also induced in Ad2-early infected monkey and hamster cells. These results imply that the 20/21K polypeptide is synthesized in Ad2-infected human, monkey, and hamster cells, and in one but not all Ad2-transformed rat cells. Thus, the 20/21K polypeptide is probably viral coded rather than cell coded and viral induced.

Adenoviruses, Human↗
PubMed1978

Transcription of the transforming region of adenovirus type 5 in a rat cell line transformed by a small restriction fragment.

The fraction of the adenovirus type 5 genome expressed as mRNA in a rat cell line, 5RK, transformed by the HsuI-G restriction fragment was analyzed by saturation hybridization using separated strands of 32P-labeled HindIII-G fragment. It was found that 45 to 50% of G fragment (about 8 X 10(5) daltons) is expressed as mRNA. The size of polyadenylic acid-terminated virus-specific cytoplasmic and nuclear RNA was determined by electrophoresis on polyacrylamide gels containing 98% formamide, followed by hybridization of gel slices with viral DNA. The major virus-specific RNA species present in the cytoplasm is about 14S, whereas the major virus-specific RNA present in the nucleus is 30 to 32S. The large size of nuclear virus-specific RNA suggests that host sequences are covalently linked to the viral transcript.

Adenoviruses, Human↗
PubMed1978

Comparison of reports on lung function tests made by chest physicians with those made by a simple computer program.

The numerical results of 60 sets of pulmonary function tests were submitted to five consultant chest physicians for independent reporting. The chest physicians' reports were compared with the reports generated by the on-line computer reporting system in routine use in the pulmonary function laboratory at Westminster Hospital. There was good agreement between the reports of the chest physicians among themselves and with the computer. The individual reports were compared with the consensus opinions of the physicians and the computer. The computer's decisions differed from the consensus opinion in 4.6% of instances. The comparable figures for the five physicians were respectively 2.9%, 2.9%, 2.9%, 4.0%, and 4.6%. Decisions differing from the consensus were due to mistakes or actual sustained disagreements of opinion. The physicians made more mistakes than the computer even though they were performing under test conditions. They made up for this, however, by producing fewer genuine disagreements from the consensus opinions. It is concluded that in routine day-to-day practice the computer report will be as consistently useful as the chest physicians' reports and more immediately available.

Airway Obstruction↗
PubMed1978

Relationship of central and peripheral airway resistance to lung volume in dogs.

We could not reconcile reported relationships between lung resistance measurements and lung volume with bronchographic and anatomic studies showing that airway diameters change monotonically with lung volume and that small airways change diameter proportionately at least as much as large ones. Accordingly we measured central and peripheral airways resistances with a new technique. The relevant pressures were measured with a tracheal cannula, a wedged retrograde catheter, and two parenchymal needles in seven open-chested dogs while pleural pressure was oscillated at 1 Hz. In contrast to previous studies, the volume dependency of peripheral resistance was at least as great as that of central resistance with vagi intact, the volume dependencies of central and peripheral resistances were not abolished by vagotomy, and neither resistance increased systematically at high volumes. Volume dependency of central resistance resembled predictions for isotropic expansion of airways with vagi cut but increased with bronchomotor tone. These results fit generally with bronchographic data. Previous studies may have been affected by volume dependency due to "tissue resistance" and catheter phase lags.

Airway Resistance↗
PubMed1978

Mesothelioma associated with the syndrome of inappropriate secretion of antidiuretic hormone.

A patient with a malignant mesothelioma developed the syndrome of inappropriate secretion of antidiuretic hormone. The electrolyte abnormalities were corrected by treatment with demethylchlortetracycline. Arginine vasopressin concentrations were increased in serum and urine. It is suggested that the syndrome might have been mediated by secretion of antidiuretic hormone from the posterior pituitary, because arginine vasopressin was not detected in the patient's tumor using a sensitive radioimmunoassay.

Humans↗
PubMed1978

The effects of mood upon imaginal thought.

The effects of mood upon imaginal thought were explored with a highly trained undergraduate female hypnotic subject. She was hypnotically programmed to experience free-floating anxiety or pleasure in varying degrees just before the exposure of combinations of three Blacky Pictures, and to produce dreamlike imagery in response to the Blacky stimuli while under sway of the mood. Data from 98 dream trials, separated by amnesia, indicated that the affective states clearly influenced imaginal processes. Blind ratings by a psychoanalyst showed the anxiety moods to be more closely associated with primary-process features characteristic of nocturnal dreams, whereas pleasure had a relatively higher incidence of daydreamlike ratings. Empirical analysis of themes yielded significant relationships of anxiety to physical injury to the self and verbal aggression toward others; pleasure was associated with circular movements and overt sex themes.

Journal Article↗
PubMed1978

The effects of mood upon imaginal thought.t.

The effects of mood upon imaginal thought were explored with a highly trained undergraduate female hypnotic subject. She was hypnotically programmed to experience free-floating anxiety or pleasure in varying degrees just before the exposure of combinations of three Blacky Pictures, and to produce dreamlike imagery in response to the Blacky stimuli while under sway of the mood. Data from 98 dream trials, separated by amnesia, indicated that the affective states clearly influenced imaginal processes. Blind ratings by a psychoanalyst showed anxiety moods to be more closely associated with primary-process features characteristic of nocturnal dreams, whereas pleasure had a relatively higher incidence of daydreamlike ratings. Empirical analysis of themes yielded significant relationships of anxiety to physical injury to the self and verbal aggression toward others; pleasure was associated with circular movements and overt sex themes.

Adult↗