Biomedical subjects

D Shedd

Publications and source records attributed to D Shedd.

At least 19 recordsLinked to original sources

PubMed2000

Kaposi's sarcoma-associated herpesvirus open reading frame 50/Rta protein activates the entire viral lytic cycle in the HH-B2 primary effusion lymphoma cell line.

Rta, the gene product of Kaposi's sarcoma-associated herpesvirus (KSHV) encoded mainly in open reading frame 50 (ORF50), is capable of activating expression of viral lytic cycle genes. What was not demonstrated in previous studies was whether KSHV Rta was competent to initiate the entire viral lytic life cycle including lytic viral DNA replication, late-gene expression with appropriate kinetics, and virus release. In HH-B2, a newly established primary effusion lymphoma (PEL) cell line, KSHV ORF50 behaved as an immediate-early gene and autostimulated its own expression. Expression of late genes, ORF65, and K8.1 induced by KSHV Rta was eliminated by phosphonoacetic acid, an inhibitor of viral DNA polymerase. Transfection of KSHV Rta increased the production of encapsidated DNase-resistant viral DNA from HH-B2 cells. Thus, introduction of an ORF50 expression plasmid is sufficient to drive the lytic cycle to completion in cultured PEL cells.

DNA, Viral↗

PubMed1998

Functional results of primary closure vs flaps in oropharyngeal reconstruction: a prospective study of speech and swallowing.

BACKGROUND: The preservation of speech and swallowing function is the primary goal when reconstructing soft tissue defects in the oral cavity or oropharynx. The type of reconstructive procedure used should be based on outcome data examining speech and swallowing function; yet, there is a paucity of such information. OBJECTIVES: To present the results of a multi-institutional prospective study of speech and swallowing function before and after soft tissue reconstruction of the oral cavity and oropharynx, and to compare 3 methods of reconstruction with respect to speech and swallowing function: primary closure, distal myocutaneous flap, and microvascular free flap. DESIGN: Prospective case-comparison study. SETTING: Four leading head and neck cancer institutions. PATIENTS: The patients were selected from a database of 284 patients treated at the different institutions. The patients were matched for the location of the oral cavity or oropharyngeal defect and the percentage of oral tongue and tongue base resection. Those patients who had previous speech and swallowing deficits and patients in whom postoperative fistulas or wound infections developed were excluded from the study. METHODS: The patients underwent speech and swallowing evaluation preoperatively and 3 months after healing. This evaluation included videofluoroscopic studies of swallowing and tests of speech intelligibility and sentence articulation. Videofluoroscopy provided measures of swallowing efficiency and bolus movement. Liquid and paste consistencies were used in evaluating swallowing function. MAIN OUTCOME MEASURE: The functional results of the reconstruction. RESULTS: Patients who had primary closure were more efficient at swallowing liquids, had less pharyngeal residue, a longer oral transit time with paste, and higher conversational intelligibility than patients who underwent reconstruction with a distal flap. Compared with patients who underwent reconstruction with a free flap, those who had primary closure had more efficient swallowing of liquids, less pharyngeal residue, and shorter pharyngeal delay times with paste. No difference in the speech and swallowing function existed between patients treated with distal myocutaneous flaps and those treated with microvascular free flaps. CONCLUSION: Contrary to the current theory of oral and oropharyngeal reconstruction, we found that the use of primary closure resulted in equal or better function than the use of flap reconstruction in patients with a comparable locus of resection and percentage of oral tongue and tongue base resection.

Deglutition↗

PubMed1998

Surgical variables affecting speech in treated patients with oral and oropharyngeal cancer.

Postoperative speech function may be influenced by a number of treatment variables. The objective of this study was to examine the relationships among various treatment factors to determine the impact of these measures on speech function. Speech function was tested prospectively in 142 patients with surgically treated oral and oropharyngeal cancer 3 months after treatment. Each patient's speech was recorded during a 6- to 7-minute conversation and while performing a standard articulation test, producing speech outcome measures of percent correct consonant phonemes and percent conversational understandability. Correlational analyses were used to determine the relationships among the speech outcome measures and 14 treatment parameters. Speech function was mildly to moderately negatively correlated with most surgical resection variables, indicating that larger amounts of tissue resected were associated with worse speech function. Overall measures of conversational understandability and percent correct consonant phonemes were related to extent of oral tongue resection, floor of mouth resection, soft palate resection, and total volume of tissue resected. These relationships varied depending on the method of surgical closure. Method of surgical reconstruction had a profound impact on postoperative speech function 3 months after treatment and was an important factor in determining how oral tongue resection influenced articulation and intelligibility. The combination of closure type, percent oral tongue resected, and percent soft palate resected had the strongest relationship with overall speech function for patients with surgically treated oral and oropharyngeal cancer 3 months after treatment.

Adult↗

PubMed1997

Selective switch between latency and lytic replication of Kaposi's sarcoma herpesvirus and Epstein-Barr virus in dually infected body cavity lymphoma cells.

The BC-1 cell line, derived from a body cavity-based, B-cell lymphoma, is dually infected with Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV). In these studies, the relationships between these two gammaherpesviruses and BC-1 cells were characterized and compared. Single-cell cloning experiments suggested that all BC-1 cells contain both genomes. In more than 98% of cells, both viruses were latent. The two viruses could be differentially induced into their lytic cycles by chemicals. EBV was activated into DNA replication and late-gene expression by the phorbol ester tetradecanoyl phorbol acetate (TPA). KSHV was induced into DNA replication and late-gene expression by n-butyrate. Amplification of both EBV and KSHV DNAs was inhibited by phosphonoacetic acid. Induction of the KSHV lytic cycle by n-butyrate was accompanied by the disappearance of host-cell beta-actin mRNA. Induction of EBV by TPA was not accompanied by such an effect on host-cell gene expression. Induction of the KSHV lytic cycle by n-butyrate was associated with the expression of several novel polypeptides. Recognition of one of these, p40, served as the basis of development of an assay for antibodies to KSHV in the sera of infected patients. BC-1 cells released infectious EBV; however, there was no evidence for the release of encapsidated KSHV genomes by BC-1 cells, even though n-butyrate-treated cells contained numerous intranuclear nucleocapsids. The differential inducibility of these two herpesviruses in the same cell line points to the importance of viral factors in the switch from latency to lytic cycle.

Animals↗

PubMed1997

Identification, expression, and immunogenicity of Kaposi's sarcoma-associated herpesvirus-encoded small viral capsid antigen.

We describe a recombinant antigen for use in serologic tests for antibodies to Kaposi's sarcoma (KS)-associated herpesvirus (KSHV). The cDNA for a small viral capsid antigen (sVCA) was identified by immunoscreening of a library prepared from the BC-1 body cavity lymphoma cell line induced into KSHV lytic gene expression by sodium butyrate. The cDNA specified a 170-amino-acid peptide with homology to small viral capsid proteins encoded by the BFRF3 gene of Epstein-Barr virus and the ORF65 gene of herpesvirus saimiri. KSHV sVCA was expressed from a 0.85-kb mRNA present late in lytic KSHV replication in BC-1 cells. This transcript was sensitive to phosphonoacetic acid and phosphonoformic acid, inhibitors of herpesvirus DNA replication. KSHV sVCA expressed in mammalian cells or Escherichia coli or translated in vitro was recognized as an antigen by antisera from KS patients. Rabbit antisera raised to KSHV sVCA expressed in E. coli detected a 22-kDa protein in KSHV-infected human B cells. Overexpressed KSHV sVCA purified from E. coli and used as an antigen in immunoblot screening assay did not cross-react with EBV BFRF3. Antibodies to sVCA were present in 89% of 47 human immunodeficiency virus (HIV)-positive patients with KS, in 20% of 54 HIV-positive patients without KS, but in none of 122 other patients including children born to HIV-seropositive mothers and patients with hemophilia, autoimmune disease, or nasopharyngeal carcinoma. Low-titer antibody was detected in three sera from 28 healthy subjects. Antibodies to recombinant sVCA correlate with KS in high-risk populations. Recombinant sVCA can be used to examine the seroepidemiology of infection with KSHV in the general population.

AIDS-Related Opportunistic Infections↗

PubMed1995

Transmissible retrovirus in Epstein-Barr virus-producer B95-8 cells.

Epstein-Barr virus (EBV) released from the B95-8 marmoset cell line has served as a prototype for biologic and biochemical studies of EBV. Here we identify and characterize a retrovirus carried by many cultures of B95-8 cells. The experiments were stimulated by the isolation of a cDNA clone from B95-8 cells in which sequences from the EBV large internal repeat were linked to gag sequences similar to those of squirrel monkey retrovirus, human isolate, SMRV-H. However, among 413 amino acids predicted from the nucleotide sequence of the gag region of the B95-8 SMRV isolate there were 48 amino acid changes that distinguished this virus from SMRV-H originally isolated from a human lymphoid cell line by Oda et al. (1988, Virology 167, 468-476). Nucleic acid and antibody probes were developed for the B95-8 isolate of SMRV. Using such probes, we found that SMRV-B95-8 was readily transmissible, independent of EBV, as an infectious virus to human B and T cell lines. SMRV-B95-8 was highly fusogenic in the presence or absence of EBV. The ultrastructural appearance of the B95-8 retrovirus was characteristic of a type D retrovirus. Cells dually infected with EBV and SMRV-B95-8 did not demonstrate increased levels of lytic EB viral replication. SMRV-B95-8 did not by itself cause lymphocyte immortalization or enhance immortalization by EBV. Thus SMRV-B95-8 does not contribute to the major biologic properties of the B95-8 strain of EBV.

Amino Acid Sequence↗

PubMed1995

In situ breast carcinoma after treatment during adolescence for thyroid cancer with radioiodine.

We reviewed the courses of patients treated during childhood or adolescence for thyroid cancer to estimate the frequency of, and to identify possible risk factors for, the occurrence of second malignant tumors in this population. We identified all patients treated for thyroid cancer in a cohort of 1,406 pediatric cancer patients who were diagnosed prior to 20 years of age during the period January 1, 1960 through December 31, 1988 and who were treated at Roswell Park Cancer Institute. Twelve patients were treated for thyroid cancer, of whom nine were women. In situ breast carcinoma was diagnosed 25 and 26 years after diagnosis of thyroid cancer in two of four women treated with radioiodine. No new cancers were diagnosed in the five women treated with thyroidectomy only. Two of four women treated for thyroid cancer during adolescence with radioiodine, which is concentrated in the breast as well as other organs, developed in situ breast carcinoma. Review of a large cohort of adolescent female thyroid cancer patients treated with radioiodine is necessary to provide an accurate estimate of their risk of developing breast cancer. These patients must remain under medical surveillance throughout their lifetimes to facilitate prompt diagnosis of and early intervention for new conditions, such as the occurrence of breast cancer.

Adolescent↗

PubMed1995

Detection of human serum antibodies to the BFRF3 Epstein-Barr virus capsid component by means of a DNA-binding assay.

A novel assay for antibodies to an immunodominant component of the Epstein-Barr virus (EBV) capsid antigen (VCA) complex was developed by creation of a chimeric protein containing the DNA-binding domain of the yeast GAL4 protein fused to the capsid antigen encoded by the BFRF3 gene of EBV. GAL4-BFRF3 antigen fusion protein bound specifically to a duplex DNA oligonucleotide containing GAL4-binding sites. Antibodies to the antigen were revealed by retardation of the electrophoretic mobility of the DNA-protein complex. Antibodies to the BFRF3 component of VCA became detectable approximately 2 months after onset of infectious mononucleosis. Kinetics of the antibody response to BFRF3 were identical using supershift or immunoblotting assays. Concordance between the DNA-binding assay and the classical indirect immunofluorescence assay for antibody to VCA was 97%. The GAL4 epitope assay is applicable for detection of antibodies to many cloned gene products.

Antibodies, Viral↗

PubMed1994

Surgical variables affecting postoperative swallowing efficiency in oral cancer patients: a pilot study.

This study examined the correlation between swallow function at 3 months postoperatively and surgical variables including volume resected, flap volume, ratio of flap volume to volume resected, percentage of oral tongue, tongue base, and anterior and lateral floor of mouth resected, and whether or not the mandible was preserved in 30 surgically treated oral cancer patients. Swallows of measured amounts of liquid and paste (pudding) materials were examined videofluoroscopically. Nine measures of swallow function were completed for each swallow. A factor analysis of all swallow variables was done for liquid and for paste consistencies to determine whether one measure was statistically representative of all swallow measures. This analysis indicated that oral pharyngeal swallow efficiency (OPSE) represented all measures for both liquid and paste consistencies. Then the correlation between OPSE and surgical variables was defined. Only percentage of oral tongue and percentage of tongue base resected were significantly negatively correlated with OPSE. That is, OPSE decreased for both liquid and paste as percentage of oral tongue or percentage of tongue base resected increased. Results are discussed in terms of diet choices and surgical management.

Deglutition↗

PubMed1993

Speech and swallowing function after anterior tongue and floor of mouth resection with distal flap reconstruction.

The purpose of this study was to assess the postoperative functioning of oral cancer patients with resections of the anterior tongue and floor of mouth, reconstructed with distal flap closure. Speech and swallowing performance was assessed for 11 men and 5 women preoperatively and at 1 and 3 months postoperatively following a standardized protocol. Speech tasks included an audio recording of a brief conversation and of a standard articulation test; swallowing function was examined using videofluoroscopy. Data were also collected on the number and duration of speech/swallowing treatment sessions, as well as the amount and duration of radiation therapy. Statistical analyses revealed that patients demonstrated a significant and severe impairment in speech and swallow functioning after surgery, with no recovery of function by 3 months post-healing. The degree of impairment in these patients may be related to the adynamic character of the distal flap used for reconstruction. Lack of improvement at the 3-month evaluation may be related to either the timing of postoperative radiation therapy or the low rate (44%) and amount of speech/swallowing treatment provided to these patients.

Adult↗

PubMed1993

Speech and swallow function after tonsil/base of tongue resection with primary closure.

Speech and swallowing function was examined in 11 patients who underwent surgical resection of greater than 1 cm of tongue base, tonsil, and faucial arch with mandible resected on the side of the tumor and reconstruction by primary closure. Preoperatively and 1 and 3 months post-healing, high fidelity audio recordings were made of a 6- to 7-minute conversational speech sample, the sentence version of The Fisher Logemann Test of Articulation Competence was administered, and videofluoroscopic assessment of oropharyngeal swallow was conducted. All subjects exhibited changes in speech and swallowing function postoperatively, with little improvement during the study. Patients exhibited greatest difficulty on stop and fricative consonants and bolus propulsion. Comparison with patients who received anterior tongue and floor of mouth resections and distal flap reconstruction revealed consistently better speech performance by the tonsil/base of tongue patients, although the same phonemes were affected. Swallow function was equally affected in the two groups. Results are discussed in terms of locus of surgical resection, nature of reconstruction, and need for swallowing therapy.

Analysis of Variance↗

PubMed1992

A chimeric mouse/human anti-IL-2 receptor antibody with enhanced biological activities.

A chimeric mouse/human MAb against the human p55 IL-2R was constructed from Ig genes isolated from a mouse hybridoma cell line, designated AHT107. AHT107 binds to a different epitope on p55 than IL-2, and similar to observations made for other rodent anti-IL-2R antibodies that do not recognize the same or spatially related epitope as IL-2, murine AHT107 did not efficiently inhibit proliferation of T-lymphocytes in mitogen and MLR PBMC stimulation assays. In contrast, the chimeric AHT107 antibodies containing a human IgG-1 constant region had substantially more anti-proliferative activity than their murine IgG-I counterparts. Our results indicated that the human constant region of the chimeric antibodies interacted more efficiently than the murine constant region with effector components present in the PBMC cultures. This conclusion was supported by our observation that F(ab')2 generated from the chimeric antibodies did not efficiently inhibit proliferation in the PBMC assays, and the chimeric antibodies did not inhibit proliferation of an antigen specific, IL-2 dependent human T-cell clone stimulated in the absence of PBMC.

Amino Acid Sequence↗

PubMed1992

Smoking, alcohol, dentition and diet in the epidemiology of oral cancer.

This matched case-control study was conducted in Western New York. The smoking, alcohol consumption, dental hygiene and diet of 290 cases were compared with those of 290 sex-, age-, and neighbourhood-matched controls. The results confirm earlier findings that cigarette smoking and alcohol consumption impart substantial risk of oral cancer. The results also confirm that poor oral hygiene increases the risk of oral cancer, although this effect is much smaller than those of cigarette smoking and alcohol consumption. The results suggest that, of macronutrients, intake of fat is more likely than those of protein or carbohydrate to be related to risk. Of micronutrients, calcium, sodium, riboflavin and retinol are associated with risk, while thiamin, niacin, and dietary fibre are associated with decreased risk. Although patterns of dietary effects are discernable, these effects are in general much weaker than are those of smoking and alcohol consumption.

Aged↗

PubMed1992

Differential effects of a murine and chimeric mouse/human anti-interleukin-2 receptor antibody on human T-cell proliferation.

The preference for interleukin-2 receptor (IL-2R) expression on activated, compared with resting T lymphocytes makes the IL-2R a promising target for selective immunosuppressive therapy. To increase the potential therapeutic effectiveness of anti-IL-2R monoclonals, a chimeric mouse/human variant was constructed from Ig genes isolated from a murine anti-human IL-2R hybridoma cell line, designated AHT54. AHT54 binds to the same or spatially related epitope as IL-2 on the p55 protein that constitutes the low- and high-affinity forms of IL-2R. Although the murine and chimeric AHT54 antibodies inhibited cell-surface binding of IL-2 to the same extent, the chimeric antibodies containing a human IgG1 constant region had substantially more anti-proliferative activity than their murine IgG1 counterparts. Our results indicated that the human constant region of the chimeric antibodies interacted more efficiently than the murine constant region with effector components present in peripheral blood mononuclear cells (PBMC).

Animals↗

PubMed1986

Deletion mutants that affect expression of Epstein-Barr virus nuclear antigen in COS-1 cells after gene transfer with simian virus 40 vectors containing portions of the BamHI K fragment.

We have identified sequences that affect the efficient expression of Epstein-Barr virus nuclear antigen (EBNA 1) when the structural portion of its gene, found within the 2.9-kilobase-pair BamHI/HindIII fragment called Ilf, is expressed from a simian virus 40 vector. A set of nested deletions at the BamHI end of the fragment was constructed by using BAL 31 digestion, the addition of linkers, and ligation into pSVOd. The mutants were tested for their ability to express antigen in COS-1 monkey cells by using indirect immunofluorescence and immunoblotting. Deletion endpoints were determined by DNA sequencing of the 5' ends of the mutants. The deletion mutants could be subclassified into four groups based on their ability to express EBNA polypeptide. Mutants that retain more than 106 base pairs upstream from the start of the open reading frame in Ilf exhibit antigen expression indistinguishable from that of wild type. Mutants that invade the structural gene by 1,115 or more bases destroy antigen expression. Mutants that alter the splice acceptor site or invade the open reading frame by a short distance make antigen at a markedly lower frequency. There are three mutants, whose deletions map at -78, -70, and -44 base pairs upstream of the open reading frame, that make reduced levels of EBNA. Since these three mutants differ in the extent to which EBNA expression is impaired, the data suggest that there are several critical regions upstream of the open reading frame that regulate EBNA expression in COS-1 cells. It is not known whether these regulatory sequences, which would be located in an intron in the intact genome, play any role in the expression of EBNA in infected lymphocytes.

Animals↗

PubMed1984

Identification of Epstein-Barr nuclear antigen polypeptide in mouse and monkey cells after gene transfer with a cloned 2.9-kilobase-pair subfragment of the genome.

A new antigenic polypeptide was identified in mouse L cells and in monkey COS-1 cells in which Epstein-Barr nuclear antigen (EBNA) was expressed as the result of gene transfer with cloned fragments of Epstein-Barr virus (EBV) DNA. The same-size protein (Mr, approximately equal to 78,000) was seen in stably transformed mouse cells harboring only the BamHI K fragment [approximately equal to 5.2 kilobase pairs (kbp)] or its BamHI/HindIII subfragment, I1f (approximately equal to 2.9 kbp). Thus, the latter DNA fragment is sufficient to code for the protein. In transfected COS cells, a deletion mutant of the I1f fragment (approximately equal to 2.3 kbp) gave rise to a truncated protein (Mr, approximately equal to 52,000), whereas the BamHI K fragment yielded a full-sized Mr 78,000 species. This finding indicates that EBNA is encoded by viral genes. In Burkitt lymphoma lines or in immortalized lymphocytes, variation in the size of the I1f fragment correlated with the apparent molecular weight of the EBNA polypeptide. EBNA is truncated in two Burkitt lymphoma lines, Raji (Mr, 67,000) and P3JHR-1 (Mr, 70,000), which have deletion mutant I1f genes. EBNA in human lymphoid cells bearing a complete I1f fragment as part of the entire EBV genome is the same size (Mr, 78,000) as EBNA found after gene transfer of I1f alone into mouse or monkey cells. Therefore, these expression systems make an authentic EBNA after transfer of the appropriate EBV genes.

Animals↗

PubMed1984

Expression in COS-1 cells of Epstein-Barr virus nuclear antigen from a complete gene and a deleted gene.

In a previous study the BamHI-K fragment of Epstein-Barr virus DNA was shown to induce a nuclear antigen, Epstein-Barr virus nuclear antigen (EBNA), when cotransfected with the herpes simplex virus thymidine kinase gene into mouse LTK- cells. We have now inserted the BamHI-K fragment and a BamHI/HindIII subfragment, I1f , into shuttle vectors containing the origin of replication of simian virus 40. These plasmids have been introduced into COS-1, which are monkey kidney cells transformed by an origin-defective simian virus 40 genome. This expression system permitted rapid characterization of antigens, mRNAs, and proteins related to EBNA. The same-sized EBNA protein (approximately 78,000) was made after transfection with BamHI-K (5.2 kilobase pairs [kbp]) or the I1f subfragment (2.9 kbp). A deletion of about 600 bp occurred when the I1f fragment was propagated on the pSV2 plasmid in Escherichia coli. The deleted fragment gave rise to a smaller protein (approximately 52,000). These data provide evidence that EBNA is encoded by the 2.9-kbp I1f and is not an induced cellular protein. Nuclear antigen and polypeptide expression occurred equally well when the Epstein-Barr virus DNA was cloned on PSV2 -gpt or pSVOd . The latter plasmid lacks sequences allowing for efficient early gene transcription as well as splicing and polyadenylation signals which are present in pSV2 . Preliminary mapping of the EBNA gene transcripts demonstrated that two mRNAs (2.9 and 2.4 kilobases [kb]) are homologous to the I1f fragment. Taken together, the data suggest that the 2.9-kbp I1f fragment contains the structural gene for EBNA synthesis. COS-1 cells will thus provide a valuable system in which to analyze functional domains of the EBNA gene.

Animals↗

PubMed1983

Two Epstein-Barr viral nuclear neoantigens distinguished by gene transfer, serology, and chromosome binding.

We recently identified, by means of cotransformation of LTK- cells, a region of the Epstein-Barr virus (EBV) genome (the BamHI K fragment) that encodes or induces an EBV nuclear neoantigen (EBNA) serologically related to the EBNA found in lymphoid cells carrying the entire EBV genome. We now find that a second EBV DNA fragment, BamHI M, is also able to give rise to cotransformed LTK- cells with stable expression of a nuclear antigen. The BamHI K and M fragments have no apparent DNA homology. Many human sera that are reactive to EBNA in Raji cells detect both antigens; however, certain anti-EBNA-positive human sera are discordant and react only with the BamHI M or only with the BamHI K nuclear antigen. Every Raji cell appears to express both "M" and "K" antigens; D98 Raji cells, a somatic cell hybrid, express only "K" antigen. The K antigen is found on metaphase chromosomes of LTK cells and Raji cells. The M-induced antigen is not located on chromosomes when the cells are in metaphase but is present as granules within the nucleus.

Animals↗