Stable expression of the reovirus mu2 protein in mouse L cells complements the growth of a reovirus ts mutant with a defect in its M1 gene

Reovirus mu2 protein was constitutively expressed in mammalian cells transfected with dicistronic constructs in which the reovirus M1 gene and the selectable neomycin-resistant gene (neo) were both driven by the same phosphoglycerate kinase promoter. Translation of neo was initiated with the cap-independent translation initiation element from encephalomyocarditis virus. Expression of mu2 protein was detected by mu2-specific antibody produced through immunization of rabbits with Trp-E-mu2 fusion proteins expressed in Escherichia coli. The expression levels of mu2 proteins of serotype 1 (T1) and serotype 3 (T3) were different and varied in different mouse cell lines with T1 being expressed more efficiently than T3. mu2 expressing L929 cell lines generated with the dicistronic constructs were highly stable. Inclusion of the transforming fragment of bovine papillomavirus in the dicistronic construct lead to higher levels of mu2 expression that were less stable and thus decreased on continued cell culture. The mu2 protein expressed in transfectants was authentic as shown by peptide mapping comparison with mu2 protein from reovirus-infected cells and that from in vitro transcription and translation of the M1 gene. It was further shown that the mu2 protein expressed in a stable L929 cell line complemented the growth of the reovirus tsH11.2 mutant with a defect in its M1 gene. It is concluded that the mu2 protein stably expressed by transfection is functionally equivalent to mu2 protein expressed by reovirus.

Translation of the reovirus M1 gene initiates from the first AUG codon in both infected and transfected cells

Reovirus mu 2 protein can be expressed via the mouse phosphoglycerate kinase promoter to low levels in stably transfected L cells. To increase mu 2 expression, the terminal regions of the M1 gene cDNA constructs were modified and the effect on mu 2 expression was analyzed. The M1 gene has a single large open reading frame beginning at nucleotide 14 with another, in frame, AUG codon at nucleotide 161 reported to be used for translation initiation. Unexpectedly, deletions of the M1 5' terminal sequence upstream of the reported translation initiation codon, AUG161, resulted in loss of detection of mu 2 expression. When expression was driven by the stronger T7 promoter in the presence of recombinant vaccinia virus expressing the T7 RNA polymerase, constructs with the M1 5'-terminal deletion produced a smaller protein product of approximately 68 kDa, compared to approximately 73 kDa for the protein produced from the full-length M1-containing constructs consistent with the loss of 49 amino acids. The amount of shorter mu 2 product was increased by producing an improved 'Kozak' consensus sequence around the AUG codon at nucleotide 161 or by introducing an internal ribosome entry site at this location. Full-length M1 gene constructs produced a protein of the same size as the authentic mu 2 protein from virus-infected cells. It was further shown that the approximately 73 kDa product was expressed when the M1 gene was in different plasmid backgrounds and even when the M1 gene transcript was preceded by a 1 kb gene. This study demonstrated that translation of the reovirus M1 gene initiates from the first AUG codon in both infected and transfected cells.

Augmentation of murine hematopoiesis by interleukin 2-activated irradiated T cells

We have examined the role of T cells activated with interleukin-2 (IL-2) in vitro and subsequently irradiated (2500 rads), in stimulating murine hematopoiesis in a syngeneic system. Our data suggest that activated, irradiated T (AIT) cells significantly increased the progenitor cell activity of T cell-depleted bone marrow (BM) both in vitro and in vivo as compared with controls (P < 0.001). The efficacy of AIT cells was comparable to that of activated, nonirradiated T (AT) cells (P > 0.05). Optimal stimulation of BM progenitor cell activity was seen when T cells were activated for 4 days and used in a BM to T cell ratio of 1:2 or 1:5. The effect of these activated cells was related to the release of factors with ability to enhance hematopoiesis. These observations may have implications in enhancing the engraftment of T cell-depleted BM in allogeneic transplantation.

Successful prenatal management of hydrops, caused by congenital cystic adenomatoid malformation, using serial aspirations

Congenital cystic adenomatoid malformation (CCAM) is a lung lesion that is now commonly diagnosed in utero with fetal ultrasonography. The described treatment of this lesion includes observation with treatment delivery, a single aspiration, thoraco-amniotic shunts, and fetal resection. This patient had an in utero diagnosis of a Stocker type I CCAM associated with hydrops. Fetal resection was not an option because of patient refusal. The fetus was treated with multiple serial aspirations. There was marked improvement of the anasarca, and subsequently the baby was born without respiratory distress. On the second day of life the CCAM began to expand, and the right lower lobe was resected. The baby's postoperative course was uneventful. CCAM with hydrops is associated with a high mortality rate. Current recommended therapy for these lesions is fetal resection or thoracoamniotic shunt. The authors' patient was treated with serial fetal thoracocenteses, with an excellent outcome. This therapy may be an alternative to fetal surgery or an adjunct to fetal surgery in selected cases.

Role of granulocyte colony-stimulating factor in preventing ceftazidime-induced myelosuppression in vitro

Ceftazidime has been reported to cause myelosuppression both in vitro and in vivo. Granulocyte colony-stimulating factor (G-CSF) is known to enhance the proliferation and differentiation of myeloid cells. The present study was carried out to define the role of G-CSF in preventing the ceftazidime-induced suppression of BM progenitor cells in vitro, and to define the mechanisms involved in ceftazidime-induced myelosuppression. Our results show that G-CSF was able to maintain the proliferative activity of BM cells in the presence of ceftazidime if it was added to the culture medium during the early phase of exposure of BM to ceftazidime. Monoclonal antibody to TNF completely inhibited the ceftazidime-induced myelosuppression. The suppressive effect on BM was mediated via CD3+ T cells whereas macrophages conferred protection against this suppression. TNF-induced suppression of BM was inhibited by G-CSF. These data suggest that G-CSF prevents the ceftazidime-induced myelosuppression by antagonizing the suppressive effect of TNF and by enhancing the proliferative activity of BM.

Induction of antitumor effect by treatment with cyclosporine A plus interferon-gamma after chemotherapy: role of cytotoxic cells

We have previously shown that administration of cyclosporine A (CsA) plus interferon-gamma (IFN) after chemotherapy to mice bearing B16 melanoma results in the generation of cells with major histocompatibility complex (MHC)-unrestricted cytotoxicity in vitro and in vivo; the antitumor effect of these cells could be attenuated by normal spleen cells. This study shows that antitumor effect after treatment with CsA plus IFN after chemotherapy was mediated by T and natural killer (NK) cells, both in vitro and in vivo. Infusion of purified T or NK cells into secondary recipients after chemotherapy resulted in a significant control in the dissemination of tumor as compared to chemotherapy alone. The antitumor potential of NK cells was at least 10 times greater than that of T cells. The effector cells could inhibit the proliferation of tumor cells in vitro without a contact between the effector and tumor cells, suggesting that antitumor effect in this system was partly related to the secretion of cytotoxic factors by the effector cells. Infusion of normal spleen cells inhibited the antitumor effect of adoptively transferred effector cells. This study defines the nature of effector cells involved in mediating the antitumor effect in this model; the optimal efficacy of these cells in the recipient is possibly related to the abolition of a suppressor system by chemotherapy.

Protective effect of granulocyte-colony stimulating factor against amphotericin B-induced myelosuppression in vitro

Amphotericin B causes suppression of bone marrow (BM) progenitor cells in vitro. Granulocyte colony stimulating factor (G-CSF) enhances the proliferation of myeloid cells. The present study defines the role of G-CSF in preventing amphotericin B-induced myelosuppression. G-CSF increased the proliferative potential of BM and protected against amphotericin B-induced myelosuppression if it was added to the medium during the early phase of exposure of BM to amphotericin B. Monoclonal antibodies to tumour necrosis factor-alpha (TNF) or interferon-gamma (IFN) inhibited the myelosuppression partially; simultaneous presence of both these antibodies completely abrogated this suppression, suggesting that both TNF alpha and IFN gamma were involved in amphotericin-induced myelosuppression. TNF- or IFN-induced suppression of BM was also inhibited by G-CSF. These data suggest that G-CSF prevents the amphotericin B-induced myelosuppression by antagonizing the suppressive effects of TNF and IFN and by enhancing the proliferative activity of BM.

The influenza virus variant A/FM/1/47-MA possesses single amino acid replacements in the hemagglutinin, controlling virulence, and in the matrix protein, controlling virulence as well as growth

Genetic analysis of mouse-adapted influenza virus variant A/FM/1/47 (FM) MA has previously identified four genome segments, 4, 5, 7, and 8, that are statistically associated with virulence. On sequencing these genome segments, we found single amino acid replacements at amino acid 47 of the HA2 subunit of the hemagglutinin and at amino acid 139 of the matrix protein. Mutation was not detected in segments 5 and 8, obviating a role for these genes in FM-MA virulence. FM-MA replicates to higher titer than FM in MDCK cells and in mouse lung. FM X FM-MA reassortants were used to show that the M1 gene controlled replication in MDCK cells as well as in mouse lung.

Use of polyethylene glycol-bound superoxide dismutase, polyethylene glycol-bound catalase, and nimodipine to prevent hypoxic ischemic injury to the brain of newborn pigs

OBJECTIVE

To determine if polyethylene glycol-bound superoxide dismutase and catalase and nimodipine, alone or in combination, will ameliorate hypoxic ischemic injury to the brain.

SUBJECTS

A total of 78 newborn (0 to 3 days) pigs were used.

DESIGN

Prospective, blinded, randomized, controlled trial.

INTERVENTIONS

The piglets were subjected to hypoxic ischemic brain injury. Carotid arteries were ligated at time 0 and BP was reduced one third by hemorrhage. At 15 mins, FIO2 was reduced to 0.6. At 30 mins, carotids were released, blood was reinfused, and FIO2 was increased to 1.0. Pigs were randomly assigned at time 35 mins to receive either: 10,000 U/kg of polyethylene glycol-bound superoxide dismutase and catalase (group 1); 0.5 mg/kg of nimodipine (group 2); both 10,000 U/kg of superoxide dismutase and catalase and 0.5 mg/kg of nimodipine (group 3); or no drugs (controls).

MEASUREMENTS

The time after reoxygenation for return of electroencephalogram, respiration, blink and pain were recorded in minutes as well as a neurologic examination at 1, 2, and 3 days and pathologic examination of the brain at 3 days, both by blinded observers.

MAIN RESULTS

There were no significant differences in the four groups.

CONCLUSIONS

Polyethylene glycol-bound superoxide dismutase and catalase, and nimodipine, either alone or in combination, do not ameliorate hypoxic ischemic injury to the brain in the newborn pig when given 5 mins after reoxygenation.

A novel approach to immunomodulation of frozen human bone marrow with interleukin-2 for clinical application

Interleukin-2 (IL-2) activation of fresh or frozen bone marrow (BM) in vitro generates killer cells with potent anti-tumor effect both in vitro and in vivo. The IL-2-activated BM (ABM) retains the capacity to reconstitute the hematopoietic system in an autologous bone marrow transplantation (ABMT) setting. The killer cells lose their cytotoxicity if the ABM undergoes the procedures of freezing and thawing. Therefore, for clinical application, the ABM has to be generated after thawing a frozen stock of BM before ABMT. The thawed BM cells are fragile and may undergo lysis, resulting in clump formation and cell loss. The frozen autograft also contains components of cryoprotectant mixture whose effects on the generation of ABM have not been defined. The present studies have been carried out to optimize a technique of handling the frozen BM for immunomodulation with IL-2 for 24 h at 37 degrees C prior to ABMT, with minimal loss of cells. IL-2-activation of BM was carried out in bags containing serum free medium which were designed to permit gaseous exchange. Addition of deoxyribonuclease (DNAse) (100 micrograms/ml of BM concentrate) immediately after thawing and the presence of heparin (20 units/ml) in the medium completely abrogated immediate or delayed clumping of cells. The presence of DNAse and/or heparin during in vitro culture did not affect the cell viability, cytotoxicity against tumor cells or the progenitor cell activity of the ABM; all these functions were well maintained even when BM was placed in culture immediately after thawing (without washing). There was no microbial contamination.(ABSTRACT TRUNCATED AT 250 WORDS)

Interference is controlled by segment 2 and possibly by segment 8 of the nondefective interfering influenza virus variant A/FM/1/47-MA

On mouse adaption of A/FM/1/47, a variant, A/FM/1/47-MA (FM-MA), that had acquired the properties of increased virulence and interference was produced. Coinfection of cells with FM-MA and prototype strains of influenza virus yielded > 100-fold more FM-MA virus than prototype virus, whereas coinfection with the same prototype strains and the parental A/FM/1/47 virus produced equivalent yields, indicating that FM-MA had acquired mutations that confer the property of interference during mouse adaption. FM-MA is a nondefective interfering virus that grows to a high titer in vivo and in vitro. It has previously been shown that segments 4, 7, and 8 and possibly segment 5 account for the increased virulence. In this study we show by genetic analysis of FM-MA x A/HK/1/68 reassortants that segment 2, coding for the polymerase-associated protein PB1, and possibly segment 8, encoding the NS1 and NS2 proteins, control the ability of FM-MA to interfere. Interference could not be overcome by increasing the titer of the coinfecting strain, but delaying FM-MA infection by 4 to 6 h did avoid interference. During interference of A/HK/1/68, protein synthesis was inhibited by less than 65% throughout coinfection. Given the kinetics of interference and the small perturbation in protein synthesis, interference appeared to occur at the level of late genome replication or virus assembly. Virulence and interference in FM-MA were not linked. An interfering avirulent FM-MA x A/HK/1/68 reassortant, E07, was capable of protecting mice against lethal pneumonia due to a virulent noninterfering reassortant, H04.

Fructose-1,6-bisphosphate does not ameliorate hypoxic ischemic injury to the central nervous system in the newborn pig

BACKGROUND AND METHODS

Fructose-1,6-bisphosphate has been shown to improve the outcome of hypoxic ischemic brain injury in adult rabbits. We wished to see if these results could be extended to a newborn animal. Twenty-four 0- to 3-day-old piglets were randomized to receive 300 mg/kg of fructose-1,6-bisphosphate 5 mins before injury, followed by a continuous infusion of 15 mg/kg/min of fructose-1,6-bisphosphate for the next 90 mins, or the equivalent volume of normal saline. Hypoxic ischemic central nervous system damage was induced by ligating both carotid arteries and reducing their BP to two thirds of the normal value for 30 mins. In the last 15 mins of this 30 mins, the FIO2 was reduced to 0.6. At 30 mins, the piglets were resuscitated with an FIO2 of 1.0, the carotid ligatures were released, and the removed blood was reinfused.

RESULTS

The neurologic examination scores at 1, 2, and 3 days after injury and pathologic examination scores at 3 days after injury were not different in the fructose-1,6-bisphosphate-treated and the control animals.

CONCLUSION

Fructose-1,6-bisphosphate does not ameliorate hypoxic ischemic brain injury in the newborn pig.

Nucleotide sequence comparison of the M1 genome segment of reovirus type 1 Lang and type 3 Dearing

The mammalian reoviruses possess a genome composed of 10 double stranded RNA segments. The serotype 1 strain Lang M1 segment was sequenced and compared to the published type 3 sequence. Both segments were 2304 base-pairs long coding for the mu 2 protein predicted to be 736 amino acids long. The sequences were highly conserved with 97.2% conservation of nucleotide sequence and 98.6% conservation of amino acid sequence. The M1 segments of serotypes 1 and 3 have recently diverged as indicated by the distribution of variation with respect to codon positions. The conservation of amino acid sequence indicated that the mu 2 protein has a relatively high functional density.

Identification of sequence elements containing signals for replication and encapsidation of the reovirus M1 genome segment

In reovirus the genetic signals that control genome replication and encapsidation are unknown. Serial passage of reovirus results in the accumulation of deletion mutants that contain fragments of genome segments. The smallest fragments found in deletion mutants will consist of the minimum essential sequences for genome replication and assembly. T1 x T3 reassortants containing the L2 segment from T3 and the M3 segment derived from T1 generate deletions in segment M1 on serial passage. Fragments of M1 segments were produced by serial passage, characterized by PAGE and Northern blotting before amplification by PCR, cloning, and sequencing. Thirteen of the smallest deletion fragments were sequenced. All of the smallest fragments contained sequences from both termini of segment M1. The smallest fragment was 344 nucleotides long. The consensus sequences consisted of 132-135 nucleotides from the 5' end of the plus strand and 183-185 nucleotides from the 3' end of the plus strand. It is concluded that these regions contain all the signals necessary for the replication and assembly of the M1 genome segment.

Nucleotide sequence analysis of Urabe mumps vaccine strain that caused meningitis in vaccine recipients

Mumps virus was isolated from the cerebrospinal fluid of eight patients who acquired meningitis within 4 weeks of immunization with live Trivirix vaccine that contains mumps (Urabe Am 9), measles (Schwarz), and rubella (RA 27/3) viruses. Part of the haemagglutinin-neuraminidase (HN) gene from three postvaccination isolates of mumps virus, three wild strains and the Urabe and Jeryl Lynn vaccine strains was cloned following polymerase chain reaction (PCR) amplification, for the purpose of sequence analysis. A 200-nucleotide portion of the cloned HN genes was sequenced and compared to published sequences of two other strains (RW and SBL-1). The postvaccination mumps strains were identical in sequence to Urabe and were distinguishable from the wild and the Jeryl Lynn vaccine strains. Twenty-two out of 200 positions were seen to vary among the group of viruses. It was concluded that the Urabe vaccine strain was the cause of postvaccination meningitis. Therefore, with effect from 1990, Trivirix measles, mumps and rubella vaccine is no longer licensed for sale in Canada.

The safety and tolerability of sumatriptan: an overview

Safety information was pooled from 4,859 patients, mainly treated in controlled clinical trials with a dispersible tablet of sumatriptan or by a subcutaneous injection, and from 1,164 patients who received placebo by these routes. Safety monitoring involved collection of all adverse events, regardless of their relationship to treatment, and included routine laboratory screening tests and some special investigations. Individuals experienced several groups of symptoms that might be considered to be features of migraine itself or of the post-migraine period or due to treatment. The commonest complaints were an unpleasant taste or pain on injection. After oral sumatriptan (100-300 mg), some events (nausea, malaise) were characteristic of migraine and others (fatigue, sedation, weakness) were characteristic of the recovery period. With subcutaneous sumatriptan (4-8 mg) similar events were observed, but certain distinctive symptoms variously described as heaviness, pressure sensation, tingling, feelings of heat or warmth, were more common and affected various parts of the body. Their early onset and transient nature suggests some pharmacological mechanism, as yet not identified. Despite the mixed picture of symptoms recorded after treatment, they were not serious, they were transient and they were accepted by patients. Close patient monitoring allowed detailed evaluation of any possible cardiovascular side-effects as seen with other anti-migraine agents, particularly ergotamine. The evidence is reassuring but, since experience in patients with symptomatic ischaemic heart disease is limited, it is recommended that they should initially be treated with sumatriptan under medical supervision for their first two or three attacks.(ABSTRACT TRUNCATED AT 250 WORDS)

Fructose-1,6-diphosphate, when given five minutes after injury, does not ameliorate hypoxic ischemic injury to the central nervous system in the newborn pig

Hypoxic ischemic injury to the brain was induced in 12 0- to 3-day-old piglets. At time 0, the carotid arteries were ligated, and the blood pressure was reduced by one third by hemorrhage. At 15 min, inspired FIO2 was reduced from 50 to 6%. After 10 min of flat EEG, the FIO2 was changes to 100%, the carotid ligations were released, and the withdrawn blood was reinfused. Five minutes after reoxygenation, the piglets were randomly assigned to either receive 350 mg of fructose-1,6-diphosphate over 5 min, followed by 6 mg/kg/min for the ensuing 50 min, or an equivalent volume of normal saline. 3 days after the experiment, the animals received a neurologic examination by a blinded observer, were then sacrificed, and the brains examined by a blinded observer. There were no significant differences in the degree of damage between the two groups.

Increased virulence of a mouse-adapted variant of influenza A/FM/1/47 virus is controlled by mutations in genome segments 4, 5, 7, and 8

To cause disease, influenza virus must possess several genetically determined abilities that mediate stages in pathogenesis. The virulent mouse-adapted variant A/FM/1/47-MA (FM-MA), derived from the avirulent A/FM/1/47 (FM) strain, had acquired mutations in genes that control virulence. The purpose of this study was to identify those genes that had mutated to result in increased virulence and to obtain viruses that differed in virulence because of differences in individual genome segments. The genes that had mutated to increase virulence were initially identified by genetic analysis of reassortants obtained by crossing FM-MA with the avirulent strain A/HK/1/68 (HK). FM-MA genome segments 4, 5, 7, and 8 were significantly associated with virulence, as determined by using the Wilcoxon ranked sum analysis. The role of FM-MA segments 4, 7, and 8 was confirmed by reintroduction of these genes into the parental strain, which also provided virus strains that differed in virulence because of mutations in individual genome segments. Segments 4, 7, and 8 were responsible for a 10(3.6)-fold increase in virulence that was proportioned 10(2.2)-, 10(0.7)-, and 10(0.8)-fold, respectively. The role of segment 5 could not be confirmed on transfer back into the parental strain because of reversion during preparation of such reassortants. The incidence of reversion was shown to be significantly associated with culturing of FM-MA in chicken embryo cells but was not associated with growth in MDCK cells. The genetic analysis of FM-MA suggests that adaptation to increased virulence is an incremental process that involves the acquisition of mutations in multiple genes, each of which plays an individual role in pathogenesis. The structural and functional properties of segments 4, 7, and 8 that control the virulence of FM-MA can now be determined by using viruses that differ in virulence because of mutations in these individual genome segments.

Experiments Directed Towards the Synthesis of Anthracyclinones. XV. Novel Synthetic Homochiral Chloroanthracyclines From Acetal Cyclization

Quinizarin (3) has been converted in seven steps into the homochiral acetal (14) in 69% overall yield, through a sequence involving reductive Claisen rearrangements of the allyl ethers (8) and (20). The acetal (15) has been converted into four novel diastereomeric 9-chloroanthracyclines (31)-(34) by an unprecedented intramolecular acetal-alkene cyclization mediated by tin(IV) chloride in N,N-dimethylformamide.

The relationship of maternal erythrocyte oxygen transport parameters to intrauterine growth retardation

The relation of fetal growth and maternal oxygen transport as assessed by red blood cell 2,3-diphosphoglycerate, hemoglobin oxygen affinity, hemoglobin, pH, and PCO2 was evaluated in 21 pregnant women. The study was performed in the third trimester and each subject evaluated had sonographic evidence of fetal growth retardation without other obvious abnormalities. Decreased maternal 2,3-diphosphoglycerate/hemoglobin molar ratio and hemoglobin oxygen affinity were related linearly to the birth weight normalized for the expected sea level values of gestational age expressed as a birth weight (gestational age-normalized) Z score. The correlation coefficients and p values were r = 0.71, p less than 0.001 and r = 0.67, p less than 0.001, respectively. The ponderal index-normalized Z score correlated with the 2,3-diphosphoglycerate/hemoglobin molar ratio (r = 0.46, p less than 0.04), but the relation was not as strong as the birth weight-normalized Z score. The crown-heel length/head circumference ratio did not correlate with the 2,3-diphosphoglycerate/hemoglobin molar ratio (r = 0.29, NS). The birth weight (gestational age)-normalized Z score did not correlate with hemoglobin, PCO2, or pH. In the regulation of hemoglobin oxygen affinity, calculations indicated that the 2,3-diphosphoglycerate/hemoglobin molar ratio played a highly significant role (p less than 0.001), pH was minimally significant (p less than 0.025), but PCO2 had little or no significant effects in this study. It appears that fetal growth is related to the maternal red blood cell oxygen transport parameters 2,3-diphosphoglycerate/hemoglobin molar ratio and hemoglobin oxygen affinity. Moreover, the 2,3-diphosphoglycerate/hemoglobin molar ratio is the principal regulator of hemoglobin oxygen affinity.

Extraction, pre-high-performance liquid chromatographic purification, and high-performance liquid chromatographic analysis of plant nucleotides

Problems encountered in obtaining reliable analytical data by HPLC for the free nucleotide constituents of plant tissues are considered and methods of overcoming them experimentally assessed. Major problems include suppression of residual phosphatase activity during extraction, and removal of pigments, phenolics, alkaloids, and other uv-absorbing nonnucleotides, prior to HPLC. An optimal combination of extraction and pre-HPLC purification techniques is discussed which, in combination with HPLC by anion exchange, yields quantitatively reliable data. The optimized procedure involves extraction with a monophasic mixture of methanol: chloroform:formic acid:water and purification of the nucleotide extract by a batch treatment with poly-N-vinylpyrrolidone, followed by ligand-exchange chromatography. The main HPLC separation uses mu Bondapak NH2 in a linear phosphate gradient and gives good resolution of all the commonly occurring plant nucleotides in a single chromatographic run.