Identification of a new gene product encoded by mRNA D of infectious bronchitis virus.
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Base Sequence↗
Biomedical subjects
T D Brown
Publications and source records attributed to T D Brown.
Completion of the sequence of the genome of the coronavirus avian infectious bronchitis virus.
The nucleotide sequence determination of the genome of the Beaudette strain of the coronavirus avian infectious bronchitis virus (IBV) has been completed. The complete sequence has been obtained from 17 overlapping cDNA clones, the 5'-most of which contains the leader sequence (as determined by direct sequencing of the genome) and the 3'-most of which contains the poly(A) tail. Approximately 8 kilobases at the 3' end of this sequence have already been published. These contain the sequences of mRNAs A to E within which are the genes for the spike, the membrane and the nucleocapsid polypeptides: the main structural components of the virion. The remainder of the sequence, equivalent to the 'unique' region of mRNA F, is some 20 kilobases in length and is thought to code for a polymerase or polymerases which are involved in the replication of the genome and the production of the subgenomic messenger RNAs. This sequence contains two large open reading frames, potentially coding for polypeptides of molecular weights 441,000 and 300,000. Unlike other large open reading frames in the virus, the 300,000 open reading frame appears to have no subgenomic RNA associated with it which would allow it to be at the 5' end of an mRNA species. Because of this, and because of the characteristics of the sequence in the region immediately upstream of its start codon, other mechanisms of translation, such as ribosome slippage, must be postulated.
Amino Acid Sequence↗
Expression of the infectious bronchitis virus spike protein by recombinant vaccinia virus and induction of neutralizing antibodies in vaccinated mice.
A cDNA clone of the infectious bronchitis virus (IBV) spike protein gene has been recombined into vaccinia virus. Cells infected with the recombinant virus synthesized IBV spike antigen which was recognized by antibody raised against purified spike protein. Immunofluorescence showed that the IBV spike antigen was transported to the infected cell surface membrane and immunoprecipitation showed the presence of the glycosylated 180K mol. wt. polypeptide precursor of the two spike subunits S1 and S2 that comigrated with this antigen from IBV-infected cells. Vaccinated mice produced antibody that recognized the IBV spike antigen by ELISA and which neutralized IBV infectivity as shown by ciliostasis tests on tracheal organ cultures.
Antibody Formation↗
A phase I study of menogaril in patients with advanced cancer.
Menogaril (7-con-O-methylnogarol) is a semisynthetic anthracycline analogue of nogalamycin that has shown good activity against a variety of experimental tumor systems as well as decreased cardiac toxicity when compared with doxorubicin in preclinical studies. Forty-one patients with refractory solid tumors received menogaril during a phase I trial at The Johns Hopkins Oncology Center (Baltimore). Menogaril was administered as an intravenous (IV) infusion on days 1 and 8 of a 28-day cycle in doses of 8 to 140 mg/m2. Eastern Cooperative Oncology Group (ECOG) grade 3 and 4 leukopenia was the principle dose-limiting toxicity and was occasionally accompanied by thrombocytopenia. Both WBC and platelet nadirs occurred between days 15 and 22. Anemia requiring transfusion was occasionally seen. Nonhematologic toxicities observed included frequent anorexia and malaise that was not dose related and postinfusion phlebitis that was dose related and occasionally dose limiting. Gastrointestinal toxicity and alopecia were infrequent and mild in severity. Three patients with cumulative doses of menogaril greater than 1,400 mg/m2 had no significant changes in ejection fractions as determined by serial gated blood pool scans. Two patients had greater than 10% decrements in ejection fractions without clinical changes at total doses of 128 and 288 mg/m2. One patient with prior anthracycline therapy and chest irradiation decreased her left ventricular ejection fraction from 52% to 30% and developed respiratory failure after two cycles of therapy in the setting of disease progression. No responses to menogaril therapy were observed. The recommended phase II dose for menogaril on this day 1 and 8 schedule is 140 mg/m2. A starting dose of 90 mg/m2 should be considered for heavily pretreated patients. In comparing results of this phase I schedule with those of other schedules, evidence for schedule-dependent toxicity differences should be sought.
Adult↗
A phase I clinical trial of recombinant DNA gamma interferon.
Recombinant gamma interferon (r-GIFN) demonstrates in vitro and in vivo characteristics that contrast with those of alpha and beta interferons. It has relatively weak antiviral properties, yet relatively potent immunomodulatory effects. A phase I trial was performed with r-GIFN (specific activity 2.6 X 10(6) IU/mg protein), administered as a continuous intravenous (IV) infusion over 24 hours for five days (Cl X 5) and repeated every 28 days. This schedule was chosen based on the short half-life of r-GIFN in animal systems and the in vitro augmentation of biologic effects with continuous exposure to interferons. Twenty-one patients with refractory solid tumors received 46 evaluable courses of therapy. The dose-limiting toxicities included fever, flu-like symptoms, cardiovascular toxicity, and neurotoxicity. The cardiovascular toxicity included hypotension and one episode of cardiac ischemia with chest pain. Neurotoxicity consisted of lethargy and confusion. These toxicities were reversible, and although dose-limiting, occurred sporadically throughout all dosage levels. Mild to moderately severe non-dose-limiting toxicities included nausea and vomiting, leukopenia, and liver function abnormalities. Other infrequent toxicities included hypocalcemia, diarrhea, constipation, and alopecia. The maximally tolerated dose of r-GIFN on this schedule is 0.5 X 10(6) IU/m2/d. Partial responses were seen in one patient with metastatic melanoma and in one patient with renal cell carcinoma. Toxicity and antitumor activity were seen at doses where interferon serum levels could not be detected by radioimmunoassay. In addition, the toxicity and antitumor activity seen were at much lower doses than previously described for shorter infusion schedules of other recombinant gamma interferon preparations. Differences in biologic activity of interferon preparations and/or differences in scheduling may account for this variability. Although this study defines a recommended phase II dose of r-GIFN based on the maximally tolerated dose, the optimal therapeutic index may exist at a lower dosage level.
Adult↗
Phase II trial of bisantrene in hepatocellular carcinoma: a Southwest Oncology Group Study.
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Adult↗
Phase II trial of recombinant beta interferon in advanced colorectal cancer.
Betaseron is a genetically altered recombinant beta interferon with in vitro properties equivalent to those of native beta interferon. Nineteen patients with measurable advanced colorectal carcinoma who had no previous chemotherapy were given 30 X 10(6) IU Betaseron by iv push on Days 1-5 and 8-12 of each 28-day cycle. One of 17 evaluable patients had a complete response after nine courses of treatment which has been sustained greater than 9 months. The overall response rate was 6% (95% confidence limits, 0%-18%). Treatment was well tolerated with toxic effects consisting of fever, flu-like symptoms, nausea and vomiting, and transient mild granulocytopenia and liver function abnormalities. All toxic effects were World Health Organization (WHO) grade less than or equal to 2. No interferon neutralizing antibody activity was detected. Phase I and preclinical data support further investigation of Betaseron with dose escalation to tolerance for individual patients, as well as investigation of concomitant therapy with 5-fluorouracil, in an attempt to improve the observed response rate in colorectal cancer.
Adenocarcinoma↗
Nucleotide sequence encoding the membrane protein of the IBV strain 6/82.
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Coronaviridae↗
Peripheral hemodynamic stability during prolonged anesthesia in the rat.
The present study tests the hypothesis that peripheral hemodynamics in the rat femoral artery remain relatively stable during 3 hours of general anesthesia. Hemodynamic variables (pulse period, maximal centerline velocity, lumen diameter, and mean volumetric flow) were measured by the 20 MHz-pulsed ultrasonic Doppler velocimeter method at 30-minute intervals. The hemodynamic variables were not statistically different during the duration of the study. The mean values were pulse period 160 +/- 2 msec, maximal centerline velocity 37.0 +/- 1.9 cm/sec, lumen diameter 0.94 +/- 0.03 mm, and mean volumetric flow 1.92 +/- 0.19 cc/min.
Anesthesia, General↗
Dynamic performance characteristics of the liquid metal strain gage.
Performance characteristics of the liquid metal strain gage (LMSG) were evaluated by both static and dynamic bench testing. Statically, the devices were found to have outputs closely proportional to engineering strains, up to strain levels of 40%. While individual gage factors varied appreciably (up to 50%), each of the gages studied showed excellent reproducibility of behavior. Dynamically, the response to sinusoidal strain inputs was frequency-independent up to 50 Hz, and there was no detectable phase shift. Similarly, the LMSG response to constant-speed displacement inputs was velocity-independent over the range of nominal strain rates from 20 s-1 to 0.02 s-1. The devices proved capable of maintaining stable outputs when held stretched to fixed lengths, even if such tests were performed immediately following stepwise displacement inputs. Thermal artifacts were found to be modest (0.185% apparent strain per degree C), and there was no appreciable sensitivity to non-axial strains. When mounted on an in vitro ligament preparation, the LMSG measured apparent ligament strain similar to that detected by a video dimension analyzer. A protocol by which an implanted LMSG could be used to infer in vivo muscle forces was demonstrated, based on recordings of tendo-Achilles strains developed by a rabbit during slow hopping.
Animals↗
Experimental determination of the linear biphasic constitutive coefficients of human fetal proximal femoral chondroepiphysis.
The mechanical properties of the cartilaginous regions of the proximal femoral epiphysis are an important factor in load transmission through the hip joint of young children. Cylindrical test specimens excised from the chondroepiphysis of human stillborn femoral heads were subjected to uniaxial loading in peripherally-unconfined compression, using a ramp/plateau input strain history. The corresponding load vs time curves were analyzed in terms of a recent analytical solution for a linear biphasic material (the well-known KLM model), allowing calculation of that model's three fundamental constitutive coefficients (permeability, equilibrium modulus and solid-phase Poisson ratio) for this material. The numerical algorithm developed to evaluate the biphasic solution yielded very precise replication of previously published KLM parametric plots. When fitted to experimental load histories, however, the model provided only a rather loose approximation of specimen behavior, due apparently to a substantial underestimation of the transient response component associated with interstitial fluid transport. Averaged over the series, the best-fit values for permeability (2.51 X 10(-15) m4 Ns-1) and equilibrium modulus (0.699 MPa) were in the range of values accepted for human adult articular cartilage. A consequence of the coarseness of the analytical curve fits was that a solid-phase Poisson ratio of 0.0 was inferred for all specimens. The permeability vs equilibrium modulus exhibited a nearly linear (r = 0.74) inverse relationship similar to that reported for adult articular cartilage.
Femur↗
Coronavirus IBV: partial amino terminal sequencing of spike polypeptide S2 identifies the sequence Arg-Arg-Phe-Arg-Arg at the cleavage site of the spike precursor propolypeptide of IBV strains Beaudette and M41.
The spike protein of avian infectious bronchitis coronavirus comprises two glycopolypeptides S1 and S2 derived by cleavage of a proglycopolypeptide So, the nucleotide sequence of which has recently been determined for the Beaudette strain (Binns, M.M. et al., 1985, J. Gen. Virol. 66, 719-726). The order of the two glycopolypeptides within So is aminoterminus(N)-S1-S2-carboxyterminus(C). To locate the N-terminus of S2 we have performed partial amino acid sequencing on S2 from IBV-Beaudette labelled with [3H]serine and from the related strain labelled with [3H]valine, leucine and isoleucine. The residues identified and their positions relative to the N-terminus of S2 were: serine, 13; valine, 6, 12; leucine, none in the first 20 residues; isoleucine, 2, 19. These results identified the N-terminus of S2 of IBV-Beaudette as serine, 520 residues from the N-terminus of S1, excluding the signal sequence. Immediately to the N-terminal side of residue 520 So has the sequence Arg-Arg-Phe-Arg-Arg; similar basic connecting peptides are a feature of several other virus spike glycoproteins. It was deduced that for IBV-Beaudette S1 comprises 519 residues (Mr 57.0K) or 514 residues (56.2K) if the connecting peptide was to be removed by carboxypeptidase-like activity in vivo while S2 has 625 residues (69.2K). Nucleotide sequencing of the cleavage region of the So gene of IBV-M41 revealed the same connecting peptide as IBV-Beaudette and that the first 20 N-terminal residues of S2 of IBV-M41 were identical to those of the Beaudette strain. IBV-Beaudette grown in Vero cells had some uncleaved So; this was cleavable by 10 micrograms/ml of trypsin and of chymotrypsin. Partial N-terminal analysis of S1 from IBV-M41 identified leucine and valine residues at positions 2 and 9 respectively from the N-terminus. This confirms the identification, made by Binns et al. (1985), of the N-terminus of S1 and the end of the signal sequence of the IBV-Beaudette spike propolypeptide. N-terminal sequencing of [3H]leucine-labelled IBV-Beaudette membrane (M) polypeptide showed leucine residues at positions 8, 16 and 22 from the N-terminus; these results confirm the open reading frame identified by M.E.G. Boursnell et al. (1984, Virus Res. 1, 303-313) in the nucleotide sequence of M. The N-terminus of the nucleocapsid (N) polypeptide appeared to be blocked.
Amino Acid Sequence↗
Cloning and sequencing of 5' terminal sequences from avian infectious bronchitis virus genomic RNA.
The subgenomic RNAs of the fowl coronavirus infectious bronchitis virus (IBV) form a 3' co-terminal or 'nested' set. The presence of non-contiguous (leader) sequences fused to the 5' termini of murine hepatitis virus mRNAs has been demonstrated using RNase T1 oligonucleotide mapping and sequencing. The presence of a leader sequence on IBV mRNA A has been demonstrated previously. In this paper the presence of a leader identical to that present on the 5' terminus of IBV mRNA A is demonstrated to be present on the 5' terminus of IBV genomic RNA. This has been achieved by sequencing of primer extension products and cDNA clones containing the genomic leader. Analysis of these clones has revealed the presence of a sequence at the leader/genome-length RNA junction which is closely related to regions of homology identified previously within the genomic RNA sequence at the leader/body junctions of subgenomic RNAs. The implications of this finding for mechanisms of coronavirus RNA synthesis are discussed.
Animals↗
A phase I trial of spirohydantoin mustard (NSC 172112) in patients with advanced cancer.
Spirohydantoin mustard (spiromustine, NSC 172112) is a classical bifunctional alkylating agent synthesized in an effort to develop antitumor agents effective against CNS tumors. The rationale was to combine the reactive moiety of an active antitumor agent with the hydantoin part of the molecule, which might serve as a carrier to cross the blood brain barrier. Thirty-eight patients with refractory solid tumors received spiromustine as part of a phase I trial at the Johns Hopkins Oncology Center. Three schedules were investigated: intravenously (IV) daily for three consecutive days, IV every other day for 3 days, and IV on a weekly basis for three doses, all cycled every 28 days. Hematologic toxicity was infrequently seen. Mild to moderate nausea and vomiting occurred on all schedules. The dose limiting toxicity was CNS toxicity characterized by mydriasis, xerostomia, lethargy, confusion, and hallucinations. This CNS toxicity was dose related, cumulative, and reversible. IV physostigmine appeared to diminish the neurotoxicity if administered before spiromustine and at frequent intervals following the drug. The maximum tolerated dose of spiromustine (without concomitant physostigmine) on the three times a week schedule is 6 mg/m2. With physostigmine pretreatment, 8 mg/m2 can be administered. The three times daily and every other day for three days schedules are not recommended for further study due to the severity of neurotoxicity. It is recommended that 6 mg/m2 be used as the starting dose for any phase II studies using the three times weekly schedule, and that physostigmine be used as needed to minimize neurotoxicity. Dose escalation above this level can be considered when individual tolerance has been established. Phase II trials to investigate the activity of this agent against primary and metastatic CNS malignancies appear indicated on the basis of three transient radiographic responses in refractory malignancies metastatic to the CNS.
Adult↗
Improvement in cardiac ectopy during gamma interferon infusion: a case report.
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Heart Defects, Congenital↗
Phase I study of alpha 2-interferon plus doxorubicin in patients with solid tumors.
Cytotoxic chemotherapy and interferon have shown synergistic antitumor activity in vitro. The purpose of this study was to determine the maximally tolerated dose of doxorubicin given every 3 weeks, in patients receiving recombinant alpha 2-interferon [10 X 10(6) IU/m2 s.c. three times per week (Monday, Wednesday, and Friday)] during the first 2 weeks of each cycle of doxorubicin. Fourteen patients received a total of 41 cycles. Hematological toxicity was dose limiting with granulocytopenia (total granulocyte count, less than 1000) occurring in 50% of patients treated with doxorubicin at 40 mg/m2 and in 25% of patients treated with doxorubicin at 30 mg/m2. Nonhematological toxicities included a flu-like syndrome, alopecia, nausea, vomiting, diarrhea, and transient mild increases in liver function tests. A partial response was seen in one patient with metastatic squamous cell carcinoma of the skin and in another patient with metastatic adenocarcinoma of the pancreas. Concomitant administration of recombinant alpha 2-interferon given on this schedule limits the amount of doxorubicin that can be administered. However, the responses noted in this study are encouraging enough to warrant additional studies of doxorubicin plus recombinant alpha 2-interferon.
Adult↗
Rationale for and conduct of a phase I clinical trial with interferon alfa-2b plus doxorubicin.
A human tumor cloning system was utilized to screen for the antitumor activity of recombinant interferon alfa-2b (Intron A) alone and in combination with standard antineoplastic agents. These in vitro studies confirmed synergistic effects of alfa-2b plus doxorubicin against primary human tumors. Based on those in vitro findings, a phase I study has been conducted by Sarosy and colleagues that demonstrated that recombinant interferon alpha-2b and doxorubicin could be given together. Myelosuppression was the dose-limiting toxicity. Because responses were noted in the phase I trials with the combination, phase II trials of the combination are warranted. Additional phase I studies that should be pursued include recombinant interferon alpha-2b plus 5-fluorouracil, interferon plus cisplatinum, and interferon plus DTIC.
Antineoplastic Combined Chemotherapy Protocols↗