This study was conducted to determine whether the perioperative administration of octreotide decreases the incidence of pancreatic anastomotic leak after pancreaticoduodenectomy for malignancy.
Three ...multicenter, prospective, randomized trials concluded that patients who receive octreotide during and after pancreatic resection have a reduction in the total number of complications or a decreased incidence of pancreatic fistula. However, in the subset of patients who underwent pancreaticoduodenectomy for malignancy, either no analysis was performed or no benefit from octreotide could be demonstrated.
A single-institution, prospective, randomized trial was conducted between June 1991 and December 1995 involving 120 patients who were randomized to receive octreotide (150 microg subcutaneously every 8 hours through postoperative day 5) or no further treatment after pancreaticoduodenectomy for malignancy. The surgical technique was standardized, and the pancreaticojejunal anastomosis was created using the duct-to-mucosa or invagination technique.
The two patient groups were similar with respect to patient demographics, treatment variables, and histologic diagnoses. The rate of clinically significant pancreatic leak was 12% in the octreotide group and 6% in the control group (p = 0.23). Perioperative morbidity was 30% and 25%, respectively. Patients who underwent reoperative pancreaticoduodenectomy had an increased incidence of pancreatic anastomotic leak, whereas those who received preoperative chemoradiation had a decreased incidence of pancreatic anastomotic leak.
The routine use of octreotide after pancreaticoduodenectomy for malignancy cannot be recommended.
We have studied tumorigenic transformation of mouse tissue culture cells by bovine papillomavirus (BPV) as a model of papillomavirus-induced cell proliferation. When BPV or its 7.9-kb full-length ...viral DNA genome induces focal transformation of mouse calls, the viral DNA is maintained in the transformed cells as multiple extrachromosomal copies. The transforming capacity was initially localized to a 69% subgenomic fragment of the viral DNA genome. We have further characterized the BPV DNA sequences that can encode the transforming function by generating and analyzing the transforming activity of a series of BPV DNA deletion mutants. The results indicated that two discontinuous segments of the viral DNA are required for transformation. One segment, near the 5′ end of the 69% transforming fragment, probably represents a control element of the viral DNA. The second segment, which lies within the 3′ end of the 69% fragment, encodes transforming sequences of the viral DNA. A retroviral control element (the long terminal repeat DNA of Harvey murine sarcoma virus) will activate the 2.3-kb segment at the 3′ end of the 69% fragment to transform the mouse cells.
Mutational Analysis of a ras Catalytic Domain Willumsen, Berthe M.; Papageorge, Alex G.; Kung, Hsiang-Fu ...
Molecular and cellular biology,
19/7/1/, Volume:
6, Issue:
7
Journal Article
Peer reviewed
Open access
We used linker insertion-deletion mutagenesis to study the catalytic domain of the Harvey murine sarcoma virus v-ras
H
transforming protein, which is closely related to the cellular ras
H
protein. ...The mutants displayed a wide range of in vitro biological activity, from those that induced focal transformation of NIH 3T3 cells with approximately the same efficiency as the wild-type v-rasH gene to those that failed to induce any detectable morphologic changes. Correlation of transforming activity with the location of the mutations enabled us to identify three nonoverlapping segments within the catalytic domain that were dispensable for transformation and six other segments that were required for transformation. Segments that were necessary for guanosine nucleotide (GDP) binding corresponded to three of the segments that were essential for transformation; two of the three segments share strong sequence homology with other purine nucleotide-binding proteins. Loss of GDP binding was associated with apparent instability of the protein. Lesions in two of the three other required regions significantly reduced GDP binding, while small lesions in the last required region did not impair GDP binding or membrane localization. We speculate that this latter region interacts with the putative cellular target of ras. The results suggest that transforming ras proteins require membrane localization, guanosine nucleotide binding, and an additional undefined function that may represent interaction with their target.
Circular DNA intermediates of Harvey murine sarcoma virus (Ha-MuSV) have been cloned in λ gtWES-λ B and shown to be capable of transforming mouse NIH 3T3 cells Hager, G. L., Chang, E. H., Chan, H. ...W., Garon, C. F., Israel, M. A., Martin, M. A., Scolnick, E. M. & Lowy, D. R. (1979) J. Virol. 31, 795-809. By using the cloned Ha-MuSV DNA insert as a parental genome, we have constructed a series of insertion-deletion mutants by inserting an octomer containing the Sal I linker sequence (G-G-T-C-G-A-C-C) into various regions of the Ha-MuSV genome after partial digestion with Hae III. After ligation into λ gtWES· λ B-Sal I vector molecules, the mutant Ha-MuSV DNAs were cloned. Fourteen insertion-deletion mutants have been mapped by restriction enzyme digestion, and their biological activities have been correlated with the locations of mutations. The mutants whose lesion mapped within 3.0 kilobases (kb) from the 3′-end of the Ha-MuSV genome retained full transforming ability. The mutants containing the Sal I linker insertion at 0.4 or 1.5 kb from the 5′-end also retained transforming ability, but the number of foci induced by the DNAs in transfection assays was greatly reduced. However, a mutant containing a deletion of 1.5 kb at the 5′-end and a mutant with a deletion of the sequences between 1.0 and 1.5 kb from the 5′-end completely lost their transforming potential. A model for the transforming region of Ha-MuSV is discussed. Furthermore, because Ha-MuSV sequences can be rescued from the mouse cells transformed by these mutants using Moloney murine leukemia virus as a helper virus, it implies that the in vitro modified DNAs may be converted into genuine mutant viruses.
Highlights • Long-term follow-up of an HPV vaccine trial started. • Control arm was lost due to crossover vaccination. • A new unvaccinated group proved to be valid.
Microinjection of monoclonal antibody Y13-259, which reacts with all known mammalian and yeast ras-encoded proteins, has previously been shown to prevent NIH 3T3 cells from entering the S phase (L. ...S. Mulcahy, M. R. Smith, and D. W. Stacey, Nature London 313:241-243, 1985). We have now found several transformation-competent mutant v-ras
H
genes whose protein products in transformed NIH 3T3 cells are not immunoprecipitated by this monoclonal antibody. These mutant proteins are, however, precipitated by a different anti-ras antibody. Each of these mutants lacks Met-72 of v-ras
H
. In contrast to the result for cells transformed by wild-type v-ras
H
, Y13-259 microinjection of NIH 3T3 cells transformed by these mutant ras genes did not prevent the cells from entering the S phase. These results imply that a transformation-competent ras gene can supply a normal essential function for NIH 3T3 cells. When the proteins encoded by the mutant ras genes were overproduced in Escherichia coli, several mutant proteins that lacked Met-72 failed to bind Y13-259 in a Western blot. However, a ras protein from a mutant lacking amino antibody, but a ras protein from a mutant lacking amino acids 72 to 84 did not. These results suggest that Y13-259 may bind to a higher ordered structure that has been restored in the mutant lacking amino acids 72 to 82.
Attempts to treat congenital protein deficiencies using bone marrow-derived cells have been reported. These efforts have been based on the concepts of stem cell plasticity. However, it is considered ...more difficult to restore structural proteins than to restore secretory enzymes. This study aims to clarify whether bone marrow transplantation (BMT) treatment can rescue epidermolysis bullosa (EB) caused by defects in keratinocyte structural proteins. BMT treatment of adult collagen XVII (Col17) knockout mice induced donor-derived keratinocytes and Col17 expression associated with the recovery of hemidesmosomal structure and better skin manifestations, as well improving the survival rate. Both hematopoietic and mesenchymal stem cells have the potential to produce Col17 in the BMT treatment model. Furthermore, human cord blood CD34⁺ cells also differentiated into keratinocytes and expressed human skin component proteins in transplanted immunocompromised (NOD/SCID/γ null c ) mice. The current conventional BMT techniques have significant potential as a systemic therapeutic approach for the treatment of human EB.
Abstract
Background
The emergence of the novel coronavirus, SARS-CoV-2, created a crucial need for accurate tests for diagnosis, assessment of prior infection, and understanding its natural history. ...Serology assays play an important role in the assessment of anti-viral immune responses and previous infections. Evaluation of serology assays with well-characterized serum and/or plasma samples is critical to determine assay performance. CDC, FDA and NCI’s Frederick National Laboratory for Cancer Research (NCI-FNLCR) have established a collaborative network to independently evaluate commercial antibody tests prior to their authorization.
Methods
Positive (n=30) serum samples with a range of anti-SARS-CoV-2 antibody titers (Table) and negative (n=80) serum and/or plasma samples were selected to establish performance evaluation panels (PEVs). Three PEVs with similar overall antibody titer distribution have been created. Negative samples were collected prior to 2020, before the SARS-CoV-2 pandemic. Positive samples were from patients previously confirmed to have SARS-CoV-2 using a nucleic acid amplification test. Each sample was characterized at CDC and NCI-FNLCR for presence/absence of SARS-CoV-2 IgM and IgG antibodies using a SARS-CoV-2 spike enzyme linked immunosorbent assay (ELISA). NCI-FNLCR also performed a SARS-CoV-2 spike Receptor Binding Domain (RBD) IgG ELISA. Positive samples were assessed at multiple dilutions. Manufacturers submitted their serology assays for evaluation by this program. The sensitivity of each test was assessed for each antibody class (IgG and IgM) and in a combined manner, where a positive result for either antibody was considered as a positive result. For combined specificity, a negative result meant a sample was negative for both antibodies (IgG and IgM).
Number of positive samples with anti-SARS-CoV-2 spike antibodies for each panel (n=30)
Results
To date, 53 serology assays have been evaluated. Sensitivity ranged from 30.0% to 100% for IgG, from 10.0% to 100% for IgM, and the combined specificity ranged from 57.5% to 100%. For 2 assays that measure total Ig, sensitivity was 96.7% and 100%.
Conclusion
This program completed over 50 performance evaluations with well-characterized PEVs. Results have been used to inform FDA regulatory decisions and are publicly available on FDA’s website.
Disclosures
Cristina Cassetti, PhD, Nothing to disclose
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