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Biomedical subjects

G Miller

Publications and source records attributed to G Miller.

At least 343 records · Page 19Linked to original sources

Characterization of the restricted component of Epstein-Barr virus early antigens as a cytoplasmic filamentous protein.

Four monoclonal antibodies produced against the restricted component of the Epstein-Barr virus (EBV) early antigen (EA-R) precipitated a polypeptide with an approximate molecular weight of 85,000. Three of these antibodies prepared against the native 85,000-molecular-weight protein (85K protein) reacted by immunofluorescence with acetone-fixed smears but not methanol-fixed smears of EBV-producing cells activated with tumor-promoting agent and sodium butyrate. The fourth monoclonal antibody which was produced against the denatured 85K protein reacted with both acetone-fixed cells and methanol-fixed cells. Blocking of direct immunofluorescence by the different monoclonal antibodies established that these monoclonal antibodies were directed against three different epitopes expressed on the 85K protein. The cytoplasmic staining pattern produced by each antibody was granular during the first 24 to 28 h after induction, developed into filamentous structures about 36 h after induction, and then began to aggregate after 48 h. Similar structures were observed in human placental cells transfected by EBV DNA and stained with three of the monoclonal antibodies. These results suggest that the EA-R polypeptide is assembled into filaments during the EBV lytic cycle. The significance of this in regards to replication has yet to be determined. Biochemical characterization of this major EA-R component did not reveal any major differences in this protein isolated from different cell lines.

Amino Acids↗

Phenobarbital improves survival in theophylline-intoxicated rabbits.

As in humans, theophylline intoxication in rabbits causes seizures and death. We studied whether the administration of phenobarbital or phenytoin following a toxic dose of theophylline would improve survival in rabbits. New Zealand white rabbits were infused intravenously with theophylline, 115 mg/kg over 50 minutes. Upon completion of the infusion, rabbits were randomized to receive either saline (control) (N = 60) or saline containing phenobarbital 20 mg/kg (N = 60), or phenytoin 12 mg/kg (N = 30), infused over 30 minutes. The number (and percentage) of rabbits surviving 24 hours in each group was: control 12 (20%), phenobarbital 30 (50%), and phenytoin 7 (23%) [X2; p less than 0.005; two-tailed]. In all fatal cases, death was preceded by a seizure; rabbits that survived did not seize. These results show that phenobarbital administered intravenously to theophylline-intoxicated rabbits prevented seizures and improved survival whereas phenytoin administration had no significant effect.

Animals↗

Chronic Epstein-Barr virus infection associated with fever and interstitial pneumonitis. Clinical and serologic features and response to antiviral chemotherapy.

Two patients developed fever, interstitial pneumonitis, and pancytopenia associated with extremely high titers of antibody to replicative antigens of the Epstein-Barr virus. In contrast to most patients seropositive for Epstein-Barr virus, neither patient had an antibody response to the Epstein-Barr nuclear antigen K polypeptide. In addition, virus isolated from one patient had a deletion of the B95-8 type in the EcoRI C region of the genome. An etiologic relation between Epstein-Barr virus replication and the clinical manifestations of this syndrome is further shown by the response of each patient to acyclovir therapy. These patients have a new Epstein-Barr-virus-associated syndrome and provide additional evidence that acyclovir may play a role in therapy for selected patients with Epstein-Barr virus infection.

Acyclovir↗

A semiquantitative probe for radiation-induced normal tissue damage at the molecular level.

Sheep antibodies to bovine type I collagen were employed in the immunohistochemical detection of type I collagen in lung tissue sections of irradiated LAF1 mice. A video image digitizing system was developed to estimate collagen levels, by assigning a numerical value (0-63) to each of approximately 53,800 picture elements (pixels) in the microscope field, according to the collagen-dependent fluorescence intensity at each locus. For lungs harvested 52 weeks subsequent to graded doses of 60Co gamma radiation between 0 and 10 Gy, a dose-dependent increase in type I collagen was observed in the alveolar walls. A reproducible increase was evident for doses as low as 5 Gy: doses of 7 to 10 Gy elicited type I collagen levels significantly elevated with respect to those of age-matched controls. These results are consistent with a role for type I collagen in the development of radiation-induced pulmonary fibrosis. The assay system developed here will be used to explore the role of connective tissue macromolecules in the development of radiation pneumonitis and fibrosis.

Animals↗

Processive action of terminase during sequential packaging of bacteriophage lambda chromosomes.

Bacteriophage lambda chromosomes are packaged in a polarized, sequential fashion from a multimeric DNA substrate. Mature chromosomes are generated when terminase introduces staggered nicks in the cohesive end sites (cos sites) bounding a chromosome. Packaging is polarized, to the initial and terminal cos sites for packaging a chromosome can be defined. To initiate packaging, terminase binds to cos at cosB, and subsequently cuts at cosN. To terminate packaging of a chromosome, a functional cosB is not required at the terminal cos. To explain this finding, it was proposed earlier that terminase scans for the terminal cosN, rather than any subsequent cosB, during packaging. In the work described here we performed helper packaging experiments to see whether processive action of terminase occurs during sequential packaging of lambda chromosomes. The helper packaging experiments involve trilysogens; strains carrying three prophages in tandem. Infection by a hetero-immune helper phage results in packaging of the repressed prophage chromosomes, since the prophage structure is analogous to the normal DNA substrate. Two chromosomes can be packaged from between the three cos sites of the prophages of a trilysogen. Both chromosomes are packaged even when the central cos is cosB-. Our interpretation of these data is that terminase is brought to the central cos by packaging; following cleavage of the central cos, the terminase remains bound to the distal chromosome; and terminase acts to begin packaging of the distal chromosome. The frequency at which terminase reads across the central cos to initiate packaging of the distal chromosome is in the range from 0.3 to 0.5 in our experiments. Reading across cos was found not to be greatly dependent on the state of cosB, indicating that cosB binding is only needed for packaging the first chromosome in a packaging series. A multilysogen was constructed in which the initial cos was cos+ and the distal cos sites were all cosB-. The initial and downstream chromosomes were found to be packaged. This result indicates that terminase that is brought to the central cos by packaging is not only able to initiate packaging of a downstream chromosome, but can also scan and terminate packaging of the downstream chromosome. A model is presented in which processive action of terminase is the basis for sequential packaging of lambda chromosomes.

Bacteriophage lambda↗

Antibody responses to two Epstein-Barr virus nuclear antigens defined by gene transfer.

By transfecting small fragments of Epstein-Barr virus (EBV) DNA into cells, we defined two nuclear antigens, termed M and K, and examined serum from 258 subjects for antibodies against these antigens. We hoped to learn whether such single-antigen systems would clarify the association of EBV with various diseases. Although reactivity to M antigen was found in only 14 per cent of healthy EBV-seropositive subjects, 90 per cent of Chinese and North African patients with nasopharyngeal carcinoma had antibody to M. Nearly all persons (96 per cent) who were EBV seropositive, as judged by their serologic reaction to a nuclear antigen encoded by the complete virus (EBNA), had a reaction to K antigen. However, serum samples from three patients with chronic active EBV infection did not react to K, even though the serum contained anti-M titers above 1:1000. Lymphoid cells from one such patient carried a normal gene for K and made K protein of correct size. Therefore, in this patient the absence of antibody to K had not resulted from a viral mutation that destroyed the K protein. These serologic studies show that some patients with chronic active EBV infection have an abnormal immune response to a specific viral gene product.

Adult↗

Regional distribution of rat brain alpha 1-adrenergic receptors: correlation between (125I)-heat membrane binding and in vitro autoradiography.

[125I]-HEAT has proven useful for in vitro autoradiography as a specific alpha 1-adrenergic radioligand. We compared the binding of [125I]-HEAT to membranes from ten brain regions with the densitometric readings of these regions in autoradiographs. There was an excellent correlation between receptor numbers from membrane binding and relative optical densities from the autoradiography. The affinity of HEAT for binding to membranes from various regions was similar. The results of this direct comparison are further evidence that HEAT binds to alpha 1-adrenergic receptors in lightly fixed tissue sections. A further interesting observation is that in regions with a heterogeneous distribution of binding sites, membrane binding may not reflect the presence of a dense local population of receptors.

Adrenergic alpha-Antagonists↗

An identification of a transforming region of Epstein-Barr viral DNA cannot be confirmed.

We have analyzed Epstein-Barr viral DNA sequences in two cell lines HI-26-36 and HI-HFX. Stoerker et al. (J. Stoerker, J.E. Holliday, and R. Glaser (1983), Virology 129, 199-206) concluded that these cells were transformed by virus that arose as the result of marker rescue of a transformation-incompetent deletion mutant of EBV. We compared viral DNA sequences in prototype EBV strains with data presented in the Virology paper. Our findings are not consistent with the data of Stoerker et al. and indicate that the cell lines supplied to us did not arise by "marker rescue" but appear to contain the Jijoye viral genome.

B-Lymphocytes↗

Sensitivity following volar V-Y plasty for fingertip amputations.

The volar V-Y plasty is a well accepted method of management for transverse fingertip amputations. It has been suggested by some authors and assumed by some surgeons that fingertip sensation is nearly normal following the procedure. Sixteen patients with twenty fingertip injuries in our series reported an average estimate of sensitivity of 73% of normal. There was diminished sensation to testing by two-point discrimination and/or von Frey monofilament testing in all fingertips when compared to the contralateral digit. Eight patients (twelve fingertips) reported hypersensitivity, particularly cryalgia. We conclude that sensation is not normal in almost all fingertips treated by V-Y plasty for transverse amputations.

Adolescent↗

Treatment of scaphoid nonunion by volar inlay distal radius bone graft.

Volar inlay corticocancellous bone grafting is an accepted method of treatment for symptomatic nonunion of the carpal scaphoid. Performance of this procedure with a radial graft without styloidectomy yields results comparable to those obtained with iliac grafting. This permits the operation to be performed through a single incision. The elimination of the need for iliac dissection avoids morbidity associated with the iliac exposure.

Adolescent↗

Candida infection in severe burns.

Candida infection has become an important cause of morbidity and death in burned or immunosuppressed patients. Two patients with extensive burn complicated with Candida infection are presented, along with the risk factors, diagnostic procedures, and current methods of treatment.

Adult↗

IQ, prognosis and Duchenne muscular dystrophy.

The verbal scales (VS-IQ) of the IQs of 25 boys with Duchenne muscular dystrophy, the total population in Western Australia older than five yrs, were recorded. All the results of those 20 yrs of age and older lay within the normal range. The mean VS-IQ of those less than 20 yrs and less than 18 yrs is compared with the mean VS-IQ of those 20 yrs and older, and 18 yrs and older, respectively. The differences between the groups are statistically significant, and it is postulated that an active management programme has revealed a population of boys with normal intelligence who have an increased chance of prolonged survival.

Adolescent↗

Activation of expression of latent Epstein-Barr herpesvirus after gene transfer with a small cloned subfragment of heterogeneous viral DNA.

We previously found that a form of Epstein-Barr virus with rearranged DNA induces replication of latent Epstein-Barr virus. We now have found that one of three fragments of this rearranged DNA, when cloned in recombinant plasmids and used to transfect cells, can activate expression of several polypeptides from a latent viral genome. The 33-kDa protein that is the product of the active fragment is likely to be responsible for disruption of latency.

Antibodies, Viral↗