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PubMedDate not supplied

Strategy for determining extractables from rubber packaging materials in drug products.

The migration of substances from rubber packaging materials into drug products can be significant with certain packaging materials in contact with organic solvent systems. Recommendations for testing drug products for leachables are continually evolving to address new developments. Testing packaging materials using simulated solvents is not always an acceptable protocol for the pharmaceutical industry. We describe a rational strategy for evaluation of the drug product for packaging extractables. A profile of the extractables from rubber packaging materials was made with a range of organic solvents and stress conditions to provide information on substances to target in the drug product. The drug product was evaluated to determine if the matrix would cause interferences that might inhibit detection of the found extractables. Analytical methods were selected based on these findings. The procedures were validated according to FDA guidelines. A stability program using time and storage conditions as variables provided information for acceptance criteria. This same strategy can be used on other types of pharmaceuticals and packaging materials.

Drug Packaging↗
PubMed1997

Hospital infant formula discharge packages. Do they affect the duration of breast-feeding?

OBJECTIVE: To determine whether the duration of breast-feeding is affected by the contents of the hospital discharge package. DESIGN: A randomized clinical trial with 2 experimental interventions (a discharge package containing a manual breast pump only and a discharge package containing a commercially prepared infant formula and a manual breast pump) and a control group who received a commercially prepared infant formula discharge package only. Sociodemographic characteristics and information concerning prior births (including feeding methods) were obtained from each mother within 48 hours of her infant's birth. Sources of influence on the mother's feeding decision, maternal attitudes concerning breast-feeding, and maternal feeding preferences were also assessed. PARTICIPANTS: The sample consisted of 763 women who had given birth who were admitted to the maternal-fetal unit of a midwestern community hospital. MAIN OUTCOME MEASURES: Information concerning current method of infant feeding was obtained from telephone interviews conducted at 2-week intervals until the infant was 16 weeks old. The data were analyzed using descriptive statistics, multivariate analysis of variance, logistic regression analysis, and survival analysis. RESULTS: The content of the hospital discharge package did not affect whether the mother engaged in exclusive or partial breast-feeding during the 16-week follow-up interval. However, there was some evidence that providing formula samples at discharge from the hospital increased the duration of exclusive breast-feeding compared with providing a manual breast pump. CONCLUSION: This study does not support the assumption that inclusion of infant formula in hospital discharge packages decreases the duration of breast-feeding.

Adult↗
PubMed1997

Release of replication-deficient retroviruses from a packaging cell line: interaction with glioma tumor spheroids in vitro.

The present study describes how various growth conditions affect gene expression and virus production from a retroviral packaging cell line (Liz 9), grown as monolayers and as multicellular spheroids. In addition, to study the direct interaction between packaging cells and tumor tissue of glioma origin, Liz 9 spheroids were confronted with tumor spheroids derived from a human glioma cell line, GaMg. The results show a progressive gene transfer into the tumor tissue, with 9% transfection efficacy after 5 days of co-culture. In comparison, no gene transfer was observed when the Liz 9 spheroids were confronted with normal brain-cell aggregates. The Liz 9 spheroids established from early-passage cultures (passages 7-14) showed limited growth during 28 days, whereas those initiated from late-passage monolayer cultures (passages 39-49) showed extensive growth. Flow-cytometric DNA profiles of monolayers and of spheroids indicated no difference in cell-cycle distribution or ploidy between early and late passages. A cell-viability assay using scanning confocal microscopy revealed mostly viable cells in the Liz 9 spheroids, with only a few dead cells scattered within the structures. The lacZ-gene expression was maintained in early- and in late-passage cultures. In comparison, in Liz 9 early-passage monolayers, the virus titer was 3.1 x 10(4) +/- 0.4 x 10(4) CFU/ml, whereas no virus titer was found in late-passage cultures. The virus titer from the Liz 9 spheroids was found to be between 10(3) and 10(4) CFU/ml. It is concluded that the virus production from packaging cells may vary, depending on passage number and tissue-culture conditions. In the present study, this is demonstrated by a complete loss in virus titer during prolonged culture of packaging cells. In addition, the 3-dimensional confrontation system described allows direct visualization of how packaging cells interact with tumor tissue. Thus, the co-culture system represents a model for studying the efficiency of packaging cells in transfecting heterogeneous tumor tissue in vitro.

Animals↗
PubMed2002

Importance of the treatment package time in surgery and postoperative radiation therapy for squamous carcinoma of the head and neck.

BACKGROUND: To determine the effect of treatment time-related factors on outcome in patients treated with surgery and postoperative radiation therapy (RT) for locally advanced squamous cell carcinoma of head and neck (SCCHN) METHODS: A retrospective review was performed on 208 consecutive patients treated from 1992 to 1997 with surgery and postoperative RT (> or =55 Gy) for SCCHN. The treatment time factors considered were (1) interval from surgery to the start of RT; (2) RT duration; and (3) the total time from surgery to completion of RT (treatment package time). Treatment package time was dichotomized into short (< or =100 days) vs long (>100 days) categories. Other variables considered were clinical and pathologic staging, margin status, RT dose, and tumor site. Patients were also divided into intermediate- and high-risk groups on the basis of eligibility for RTOG 95-01. Univariate (logrank) and multivariate analyses were performed. RESULTS: Median follow-up for surviving patients was 24 months. Actuarial 2-year locoregional control (LRC) and survival rates were 82% and 71%, respectively. In univariate analysis, factors associated with higher locoregional failure were high-risk group (p =.011), margin status (p =.038), pathologic stage (p =.035), clinical N stage (p =.006), package time (p =.013), and RT treatment time (p =.03). Package time was also a significant predictor of survival in univariate analysis (p =.021). The other two individual time factors, tumor factors, and RT dose were not significant. Both risk status and treatment package time were significant factors in a multivariate model of LRC. CONCLUSIONS: A total treatment package time of <100 days is associated with improved tumor control and survival. Every effort should be made to keep the time from surgery to the completion of postoperative RT to <100 days.

Adult↗
PubMed1996

The simian virus 40 packaging signal ses is composed of redundant DNA elements which are partly interchangeable.

Using the experimental system of simian virus 40 (SV40) pseudovirions we have previously shown that SV40 requires a specific DNA element for packaging, ses, which was mapped to the SV40 regulatory region. ses was previously found to play a role in facilitating the nucleosomal rearrangement required for chromatin condensation and viral packaging. Here, the fine structure of ses was investigated by genetic studies. Analyses of ses+ revertants indicated that in order to function, ses must be present in close proximity to the origin of replication (ori), supporting a role in the regulation of the viral life cycle. Fine dissection of ses was performed using a series of plasmids carrying mutations and deletions in this region. The results suggest that multiple DNA elements participate in the SV40 packaging process, including the GC-boxes and elements derived from the enhancer. The elements are redundant, and they can function in various combinations. Packaging efficiency correlated with the number of GC-boxes, known to bind Sp1. In addition, AP-2 binding elements appeared to more important than others. These findings were supported by experiments which showed that packaging was significantly enhanced by adding AP-2 binding sites to plasmids with large deletions and lacking those sites. The results imply that binding of Sp1 and/or AP-2 may participate in the packaging process.

Animals↗
PubMed1996

Sequential headful packaging and fate of the cleaved DNA ends in bacteriophage SPP1.

The virulent Bacillus subtilis bacteriophage SPP1 packages its DNA from a precursor concatemer by a headful mechanism. Following disruption of mature virions with chelating agents the chromosome end produced by the headful cut remains stably bound to the phage tail. Cleavage of this tail-chromosome complex with restriction endonucleases that recognize single asymmetric positions within the SPP1 genome yields several distinct classes of DNA molecules whose size reflects the packaging cycle they were generated from. A continuous decrease in the number of molecules within each class derived from successive encapsidation rounds indicates that there are several packaging series which end after each headful packaging cycle. The frequency of molecules in each packaging class follows the distribution expected for a sequential mechanism initiated unidirectionally at a defined position in the genome (pac). The heterogeneity of the DNA fragment sizes within each class reveals an imprecision in headful cleavage of approximately 2.5 kb (5.6% of the genome size). The number of encapsidation events in a packaging series (processivity) was observed to increase with time during the infection process. DNA ejection through the tail can be induced in vitro by a variety of mild denaturing conditions. The first DNA extremity to exit the virion is invariably the same that was observed to be bound to the tail, implying that the viral chromosome is ejected with a specific polarity to penetrate the host. In mature virions a short segment of this chromosome end (55 to 67 bp equivalent to 187 to 288 A) is fixed to the tail area proximal to the head (connector). Upon ejection this extremity is the first to move along the tail tube to exit from the virion through the region where the tail spike was attached.

Bacillus Phages↗
PubMed1994

The proximate 5' and 3' ends of the 120-base viral RNA (pRNA) are crucial for the packaging of bacteriophage phi 29 DNA.

In vitro mutagenesis was performed to identify the DNA packaging domain of the 120-base pRNA essential and specific for DNA encapsidation by bacteriophage phi 29 of Bacillus subtilis. All deletions and mutations targeted the 5' and 3' ends of the pRNA. DNA templates of a control or mutant pRNAs used for in vitro transcription with T7 RNA polymerase were generated by PCR. Fourteen mutant pRNA molecules were synthesized from DNA templates either directly after PCR or after cloning the PCR fragments into the pCR II vector. Ten of the mutant pRNA species were inactive in packaging of the phi 29 genome. Mutation of base one at the 5' end did not affect the pRNA packaging activity. Mutation of the first two bases at the 5' end of the pRNA to noncomplementary bases in the predicted RNA secondary structure (U1 C2/A117G116 to G1 G2/A117G116) resulted in a pRNA with no detectable DNA-gp3 packaging activity assayed by either sucrose gradient sedimentation or agarose gel electrophoresis, and 10(5)-fold reduction in activity was found when measured by plaque-forming units with a new highly sensitive assay system. Changing bases 116 and 117 so that they were complementary to the mutated bases, 1 and 2, from the previous mutant (G1 G2/A117G116 to G1 G2/C117C116) generated an RNA molecule with restored DNA packaging ability. Our results show that, although not essential for procapsid binding, both the 5' and 3' ends of the pRNA were proximate and crucial for phi 29 DNA packaging.

Bacillus Phages↗
PubMed1995

Packaging of multiple copies of reduced-size genomic segments by bacteriophage phi 6.

Bacteriophage phi 6 has a genome of three segments of double-stranded RNA enclosed in a polyhedral procapsid. The preformed procapsid is capable of packaging plus-strand transcripts of the genomic segments in an in vitro reaction. Packaging of individual segments is dependent upon unique packaging sequences of about 300 nucleotides near the 5' ends of the segments. We have prepared segments L, M, and S with internal deletions that decrease their size by as much as sixfold without affecting either their packaging sequences or their 3' ends. Although packaging of genomic segments is normally very precise, with only one of each in a procapsid, these smaller segments are packaged in multiples such that the total number of nucleotides for each segment class approaches that of the normal genomic segment.

Bacteriophages↗
PubMed1996

DNA sequences responsible for specificity of DNA packaging and phage growth interference of bacteriophages T3 and T7.

T3 and T7 phages package recombinant plasmids carrying DNA necessary for DNA packaging (the pac sequences) of T3 and T7, respectively. Packaging is specific between T3 and T7. The pac sequence has a bipartite structure, consisting of target sequences for processing of concatemeric DNA (pac C) and its left side flanking sequence containing a promoter for phage RNA polymerase (pac B). To determine the sequences responsible for the specificity of plasmid DNA packaging, plasmids chimeric for the pac B and pac C sequences of T3 and T7 were constructed. Analysis of packaging of the chimeric plasmid DNAs showed that pac B is responsible for the packaging specificity of T3 and T7 DNAs. Plasmids carrying the genetic right end of T3 and T7 DNA interfered with the growth of T3 and T7 phages, respectively. Interference was specific between T3 and T7. pac B and sequences between pac B and pac C, but not pac C, were responsible for the interference. The specificity of interference was determined by pac B and sequences responsible for interference were partially defined.

Bacteriophage T3↗
PubMed1998

DNA requirements in vivo for phage T4 packaging.

Phage T4 terminase, comprising the products of genes 16 and 17, packages headfuls of DNA from a concatemer but its mechanism of DNA recognition remains to be determined. Phage T4 terminase gene sequences were introduced into prophage lambda imm434 and plasmids in order to assess their effect on packaging as measured by transduction frequency and DNA content of T4-transducing particles. Multiple copy prophage lambda imm434 genes were transduced at 100-fold higher frequency, and high copy plasmids were transduced at 1000-fold higher frequency than single copy prophage or chromosomal genes T4 16 gene inserts enhanced both prophage and plasmid packaging; terminase gene-containing plasmid DNA in T4 transducing particles could exceed 10% of the total. Deletion or base change of the 24-bp gene 16 3' region which is required for sequence specific amplification of terminase gene 17 (Hp 17 mutations) depressed these elevated plasmid transduction frequencies, suggesting that this is a preferred T4 pac sequence. Moreover, a specific gene 16-containing pac fragment could be detected in mature, packaged phage T4 DNA following restriction endonuclease digestion. We conclude that both the copy number of homologous sequences and the DNA pac sequence(s) themselves are important for packaging, consistent with a synapsis model for regulation of terminase cutting and packaging in phage T4.

Bacteriophage T4↗
PubMed1998

DNA packaging by L1 and L2 capsid proteins of bovine papillomavirus type 1.

Encapsidation of circular DNA by papillomavirus capsid protein was investigated in Cos-1 cells. Plasmids carrying both an SV40 origin of replication (ori) and an E. coli ori were introduced into Cos-1 cells by DNA transfection PV capsid proteins were supplied in trans by recombinant vaccinia viruses. Pseudovirions were purified from infected cells and their packaged DNA was extracted and used to transform E. coli as an indication of packaging efficacy. VLPs assembled from BPV-1 L1 alone packaged little plasmid DNA, whereas VLPs assembled from BPV-1 L1 + L2 packaged plasmid DNA at least 50 times more effectively. BPV-1 L1 + L2 VLPs packaged a plasmid containing BPV-1 sequence 8.2 +/- 3.1 times more effectively than a plasmid without BPV sequences. Using a series of plasmid constructs comprising a core BPV-1 sequence and spacer DNA it was demonstrated that BPV VLPs could accommodate a maximum of about 10.2 kb of plasmid DNA, and that longer closed circular DNA was truncated to produce less dense virions with shorter plasmid sequences. The present study suggests that packaging of genome within PV virions involves interaction of L2 protein with specific DNA sequences, and demonstrates that PV pseudovirions have the potential to be used as DNA delivery vectors for plasmids of up to 10.2 kb.

Animals↗
PubMed2003

Regulation of adenovirus packaging.

The application of fundamental concepts about the packaging of the adenovirus genome has contributed significantly to the development of therapeutic viral vectors for gene therapy. The packaging of adenovirus DNA into virus particles requires a cis-acting domain at the left end of the genome. This region contains a series of repeated sequences, termed A repeats due to their AT-rich character, that direct the packaging process. A repeats are believed to represent the binding sites for viral and cellular factors that mediate viral DNA packaging. This review will focus on fundamental aspects of adenovirus DNA packaging as well as how this information has been used and may be used to augment the selectivity of viral DNA packaging in applications pertaining to gene therapy vectors.

Adenoviridae↗
PubMed1978

Packaging of ColE1 DNA having a lambda phage cohesive end site.

The mechanism of lambda phage-mediated transduction of hybrid colicin E1 DNAs of various lengths was studied, and factors influencing the formation of these transducing particles were investigated. The results were as follows: 1. The presence of a cohesive end site of lambda phage (coslambda) on colicin E1 DNA was essential for packaging of the DNA. 2. Packaging of colicin E1 DNAs, which carry coslambda with molecular sizes corresponding to 68% of that of lambda phage DNA, was observed in the absence of all known recombination functions of E. coli K-12 and of lambda phage. 3. Hybrid colicin E1 DNAs having coslambda with molecular sizes corresponding to 28% of that of lambda phage DNA were packaged within lambda phage particles as trimers; hybrid DNAs with coslambda of 40 and 47% of the length of lambda phage DNA were packaged as dimers; and those with molecular sizes of 68% of that of lambda phage DNA were packaged mostly as monomers. These results demonstrated that two factors are essential for the packaging of DNAs within lambda phage particles; the presence of coslambda on the DNA molecule and an appropriate size of DNA.

Bacteriocin Plasmids↗
PubMed1985

A coupled in vitro system for the formation and packaging of concatemeric phage T1 DNA.

Extracts derived from E. coli cells infected non-permissively with phage T1 amber mutants were used in an in vitro system to investigate the packaging of T1 DNA into phage heads. The standard extract used infections with amber mutants in genes 1 and 2 (g1- g2-) which are defective in T1 DNA synthesis but can synthesis the proteins required for particle morphogenesis. g1- g2- extracts packaged T1+ virion DNA molecules with an efficiency of 3 X 10(5) pfu/micrograms DNA. Extracts from cells infected with phage also defective in DNA synthesis but carrying additional mutations in genes 3.5 or 4 which are required for concatemer formation in vivo (g1- g3.5- and g1- g4- extracts) package T1 virion DNA at substantially lower efficiencies. Analysis of the DNA products from these in vitro reaction showed that concatemeric DNA is formed very efficiently by g1- g2- extracts but not by g1- g3.5- or g1- g4- extracts. These results are interpreted as evidence that the T1 in vitro DNA packaging system primarily operates in a similar manner to the in vivo headful mechanism. This is achieved in vitro by the highly efficient conversion of T1 virion DNA into concatemers which are then packaged with a much lower efficiency into heads to form infectious particles. A secondary pathway for packaging T1 DNA into heads and unrelated to the headful mechanism may also exist.

DNA Replication↗
PubMed1994

The storage effects of calcium-fortified orange juice concentrate in different packaging materials.

Orange juice concentrate has been fortified with calcium in order to fulfil part of the recommended daily allowance of calcium and to overcome the problem of the shortage of milk and dairy products in Egypt. The loss of quality of calcium-fortified and unfortified orange juice concentrate was evaluated in three different packaging materials and when stored for ten weeks at room temperature. The results showed that vitamin C content decreased during storage for both the fortified and the unfortified samples. The trend of ascorbic acid breakdown was similar in all packaging treatments. The total titratable acidity declined during storage period; however, the decline was higher in the unfortified sample than in the fortified one. Also, the pH values increased along with the storage period. The results illustrated that the color values of both the fortified and unfortified diluted orange juice concentrate changed little at the end of the storage period. However, the samples packaged in low density polyethylene bags had the higher orange in the color values R and Y. The changes in the iron content for both samples was negligible during the storage period. However, a very slight change in the calcium content (4.5% and 4%) was observed after ten weeks of storage for both the unfortified and the fortified samples respectively. The acceptability of fortified orange juice rated higher than the unfortified one. The panelists' evaluation values were affected by the packaging treatment and storage time. The samples packaged in low density polyethylene bags had a higher level of decline of the panelists' evaluations than the ones packaged in laminated pouches or cans, while the latter had a lower level of decline.

Ascorbic Acid↗
PubMed1986

Overproduction and purification of the products of bacteriophage T3 genes 18 and 19, two genes involved in DNA packaging.

The products of gene 18 (gp18) and gene 19 (gp19) of bacteriophage T3 are noncapsid proteins involved in DNA packaging. A restriction fragment containing gene 18 or 19 was cloned into the plasmid vector pNT45 under the control of the inducible leftward promoter (PL) of phage lambda. Induction of transcription of gene 18 or 19 by derepression of the PL promoter led to the synthesis of a high level of gp18 or gp19. By using complementation of T3 DNA packaging in vitro as an assay, gp18 and gp19 were purified to near homogeneity. The overall yields of gp18 and gp19 were 1.4 mg and 0.35 mg, respectively, from 1 g wet wt cells. Addition of gp18 to the in vitro DNA packaging system resulted in increased phage production with increasing amounts of gp18 until 10% of the DNA was packaged into infectious phage particles. In contrast, addition of gp19 to the packaging system initially caused an increase in phage production, but increasing amounts of gp19 inhibited DNA packaging.

Cloning, Molecular↗
PubMed1988

Packaging and transduction of non-T3 DNA by bacteriophage T3.

A defined in vitro system for packaging T3 DNA also packaged other linear DNAs, including T4, lambda, and plasmid DNAs. The packaging capacity was determined to be 40 kb (kilobase pairs) by measuring the packaged length of T4 DNA. Packaged lambda and plasmid DNAs were injected into host cells to form plaques and transductants, respectively. The yield of transducers increased by using artificially ligated plasmid oligomers. The T3 mutant in gene 3 endonuclease (T3 3-) packaged plasmid DNA during abortive infection and transduced it into the recipient. Transduction of recombinant plasmids was not affected by the presence of the terminally redundant sequence (TR sequence) but increased by 4 orders of magnitudes when the genetic right-end 2.7-kb sequences, containing gene 19 (E1) but lacking TR, were present and by 7 orders when both E1 and TR sequences were present. However, these sequences did not increase transduction of these plasmids by T7 3-. Analysis of the structure of transduced plasmid DNAs indicates that transducing particles carry head-to-tail oligomers of plasmid DNA with the same termini as those of T3 genomic DNA. The mechanism of formation of transducing particles is discussed.

Bacteriophage lambda↗
PubMed1992

Identification of a generalised packaging sequence for D-type retroviruses and generation of a D-type retroviral vector.

In order to construct vectors based upon D-type, rather than C-type, retroviruses, we have identified a 624-bp fragment of Mason-Pfizer monkey virus (MPMV) which constitutes a packaging sequence for at least two D-type retroviruses. When this fragment was included in an extensively deleted D-type vector genome, the D-type viruses MPMV and SRV-5, but not the C-type viruses MLV-A or MLV-E, rescued the vector RNA from HeLa cells. The recombinant virus stocks have the host range of the rescuing D-type virus as shown by expression of an internal (SV40-puromycin) cassette replacing the retroviral structural genes. The recombinant MPMV was specifically neutralized by anti-MPMV serum and receptor interference was demonstrated when it was plated on cells productively infected with wild type MPMV. When the putative D-type packaging sequence was removed from the vector genome, even though the other sequence elements required for efficient reverse transcription remained, the vector was no longer rescued from HeLa cells. These results complement the recent demonstration of broad specificity of rescue of a C-type vector (carrying only the packaging sequence of Mo-MLV) by several different C-type, but not D-type, viruses. Replacement of the D-type packaging sequence by most of the extended packaging sequence of Mo-MLV prevented the otherwise D-type vector from being rescued by D-type viruses and did not allow it to be rescued by C-type viruses. This was probably because of the incompatibility of the D-type vector sequences with the C-type retroviral proteins involved in viral reverse transcription and integration. Hence, we have localized a packaging sequence that is recognized by D-type, but not by C-type, retroviruses and have constructed a D-type vector which may be useful in gene transfer experiments.

Betaretrovirus↗