Biomedical subjects

T T Wu

Publications and source records attributed to T T Wu.

At least 55 records · Page 3Linked to original sources

PubMed2000

Rta of murine gammaherpesvirus 68 reactivates the complete lytic cycle from latency.

Herpesviruses are characterized as having two distinct life cycle phases: lytic replication and latency. The mechanisms of latency establishment and maintenance, as well as the switch from latency to lytic replication, are poorly understood. Human gammaherpesviruses, including Epstein-Barr virus (EBV) and human herpesvirus-8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), are associated with lymphoproliferative diseases and several human tumors. Unfortunately, the lack of cell lines to support efficient de novo productive infection and restricted host ranges of EBV and HHV-8 make it difficult to explore certain important biological questions. Murine gammaherpesvirus 68 (MHV-68, or gammaHV68) can establish de novo lytic infection in a variety of cell lines and is also able to infect laboratory mice, offering an ideal model with which to study various aspects of gammaherpesvirus infection. Here we describe in vitro studies of the mechanisms of the switch from latency to lytic replication of MHV-68. An MHV-68 gene, rta (replication and transcription activator), encoded primarily by open reading frame 50 (ORF50), is homologous to the rta genes of other gammaherpesviruses, including HHV-8 and EBV. HHV-8 and EBV Rta have been shown to play central roles in viral reactivation from latency. We first studied the kinetics of MHV-68 rta gene transcription during de novo lytic infection. MHV-68 rta was predominantly expressed as a 2-kb immediate-early transcript. Sequence analysis of MHV-68 rta cDNA revealed that an 866-nucleotide intron 5' of ORF50 was removed to create the Rta ORF of 583 amino acids. To test the functions of MHV-68 Rta in reactivation, a plasmid expressing Rta was transfected into a latently infected cell line, S11E, which was established from a B-cell lymphoma in an MHV-68-infected mouse. Rta induced expression of viral early and late genes, lytic replication of viral DNA, and production of infectious viral particles. We conclude that Rta alone is able to disrupt latency, activate viral lytic replication, and drive the lytic cycle to completion. This study indicates that MHV-68 provides a valuable model for investigating regulation of the balance between latency and lytic replication in vitro and in vivo.

Animals↗

PubMed2000

Phase II evaluation of preoperative chemoradiation and postoperative adjuvant chemotherapy for squamous cell and adenocarcinoma of the esophagus.

PURPOSE: This phase II trial evaluated continuous-infusion cisplatin and fluorouracil (5-FU) with radiotherapy followed by esophagectomy. The objectives of this trial were to determine the complete pathologic response rate, survival rate, toxicity, pattern of failure, and feasibility of administering adjuvant chemotherapy in patients with resectable cancer of the esophagus treated with preoperative chemoradiation. PATIENTS AND METHODS: Patients were staged using computed tomography, endoscopic ultrasound, and laparoscopy. The preoperative treatment plan consisted of continuous intravenous infusion of cisplatin and 5-FU and a total dose of 44 Gy of radiation. Esophagogastrectomy was planned for approximately 4 weeks after the completion of chemoradiotherapy. Paclitaxel and cisplatin were administered as postoperative adjuvant therapy. RESULTS: Forty-two patients were enrolled onto the trial. Of the 39 patients who proceeded to surgery, 29 responded to preoperative treatment: 11 achieved pathologic complete response (CR) and 18 achieved a lower posttreatment stage. Five patients had no change in stage, whereas eight had progressive disease (four with distant metastases and four with increases in the T and N stages). At a median follow-up of 30.2 months, the median survival time has not been reached and the 2-year survival rate is 62%. The median survival of pathologic complete responders has not been reached, whereas the 2-year survival rate of this group is 91% compared with 51% in patients with complete tumor resection with residual tumor (P =.03). CONCLUSION: An excellent survival rate, comparable to that of our prior preoperative trial, was achieved with lower doses of preoperative cisplatin and 5-FU concurrent with radiotherapy.

Adenocarcinoma↗

PubMed2000

Calculated electric field induced in bundles of long cells in the human body when it is exposed to low-frequency electric fields.

A theoretical analysis is made of the electric field induced in the interior of long cylindrical cells arranged in bundles of parallel cells embedded in the saline fluid in the human body exposed to extremely low-frequency (ELF) and very low-frequency (VLF) electric fields parallel to the length of the cells. Such bundles characterize muscle. The analysis parallels in many respects the earlier study of isolated long cells (King and Wu, Phys. Rev. E 58, 2363-2369, 1998) but has important added complications. It leads to a similar result: The field inside the membrane of each long cell is the same as the field just outside the membrane in the saline fluid; i.e., the membrane provides no shielding. While one might expect the presence of the neighboring cells to provide a shielding effect for each cell, the results of this study show quantitatively that this is not the case. In fact, the electric field in the interior of each of a bundle of long cells is seen to increase very slightly (of the order of 0.4%) when the cells in the bundle are moved close enough to be practically in contact.

Cell Membrane↗

PubMed2000

Prediction of biochemical relapse for stage pT3 prostate cancer following radical prostatectomy.

BACKGROUND: Approximately 30% to 50% of clinically localized prostate cancers are found to be locally advanced after radical prostatectomy. Without adjuvant therapy, more than 30% of stage pT3 patients will have biochemical failure in a median follow-up of three years. Whether adjuvant therapy should be given remains controversial. Identification of prognostic indicators may be helpful to select patients at risk of biochemical failure for postoperative adjuvant therapy. METHODS: The medical records of 22 pT3 prostate cancer patients were analyzed retrospectively. Postoperative management included surveillance (7 patients), adjuvant hormone therapy (7) and radiotherapy (8). Patients were monitored every three months using serum prostate-specific antigen (PSA). Biochemical failure was defined as an elevation in PSA of more than 0.2 ng/ml. The clinical outcome was correlated with tumor grading, pathologic staging, preoperative PSA level, and p53 and bcl-2 status. RESULTS: Five patients (23%) experienced biochemical relapse within a median follow-up time of 52 months (range, 10-71 months). A Gleason score of 8 or more (p = 0.001) and seminal vesicle involvement (p = 0.014) were significant prognostic indicators in the univariate analysis. Patients with low preoperative PSA levels (< 20 ng/ml) had a significantly higher failure rate (p = 0.031). However, most of these patients (56%) had tumors with Gleason scores of 8 or more. Neither p53 gene mutation nor bcl-2 overexpression predicted PSA failure. Postoperative adjuvant therapy did not appear to reduce the risk of disease recurrence. In multivariate analysis, the Gleason score was the only significant factor predicting biochemical failure (p = 0.017). CONCLUSIONS: Patients with poorly differentiated tumors and/or seminal vesicle invasiveness are at higher risk of biochemical failure after radical prostatectomy. Our limited experience did not support the routine application of adjuvant therapy for this subgroup of patients. A larger sample size with a longer follow-up period is necessary to reach a definitive conclusion.

Aged↗

PubMed2000

Pneumonia caused by penicillin-nonsusceptible Streptococcus pneumoniae: clinical characteristics, prognostic factors, and outcomes.

BACKGROUND AND PURPOSE: Pneumococcal pneumonia caused by penicillin-nonsusceptible Streptococcus pneumoniae (PNSSP) is increasing worldwide. To better understand this infection, patients with pneumococcal pneumonia treated at National Taiwan University Hospital during a 5-year period were evaluated to determine the clinical characteristics, prognostic factors, and outcomes of the infection. METHODS: Eighty-one patients with 81 episodes of pneumococcal pneumonia diagnosed from January 1993 to December 1997 were analyzed retrospectively. Patients were categorized into two groups according to susceptibility results. Differences between groups were evaluated with Student's t-test and the chi-square test. Univariate analysis was used to identify factors associated with mortality. RESULTS: Infections were caused by penicillin-susceptible S. pneumoniae (PSSP) in 57 (70%) patients and by PNSSP in the remaining 24 (30%). Nosocomial acquisition was more common in PNSSP (25%) than in PSSP patients (10%) (p = 0.05), while the frequency of bacteremia (54% vs 60%) and the mortality rate (46% vs 32%) did not differ significantly between the PNSSP and PSSP groups. Among the 24 patients with pneumonia caused by PNSSP, those 65 years of age or older had a lower incidence of bacteremia (4/14, 29%) than those who were younger (9/10, 90%) (p = 0.03). In patients with pneumonia caused by PNSSP, the outcome was not significantly related to the treatment regimen (penicillin vs nonpenicillin beta-lactam antibiotics or vancomycin, 33% vs 47%; p = 0.4). The only factors associated with mortality from these infections were shock (p = 0.003) and multilobar consolidation (p = 0.01) at the time of admission. CONCLUSIONS: These data suggest that the clinical outcome of pneumococcal pneumonia is more closely related to the clinical condition at presentation than the susceptibility status of the pneumococcus.

Adult↗

PubMed1999

Interaction of non-competitive blockers within the gamma-aminobutyric acid type A chloride channel using chemically reactive probes as chemical sensors for cysteine mutants.

Selected channel-lining cysteine mutants from the M2 segment of rat alpha1 gamma-aminobutyric acid (GABA) type A receptor subunit, at positions 257, 261, 264, and 272 were co-expressed with beta1 and gamma2 subunits in Xenopus oocytes. They generated functional receptors displaying conductance and response to both GABA and picrotoxinin similar to the wild type alpha1beta1gamma2 receptor. Three chemically reactive affinity probes derived from non-competitive blockers were synthesized to react with the engineered cysteines: 1) dithiane bis-sulfone derivative modified by an isothiocyanate function (probe A); 2) fiprole derivatives modified by an alpha-chloroketone (probe B) and alpha-bromoketone (probe C) moiety. These probes blocked the GABA-induced currents on all receptors. This blockade could be fully reversed by a washing procedure on the wild type, the alpha1T261Cbeta1gamma2 and alpha1L264Cbeta1gamma2 mutant receptors. In contrast, an irreversible effect was observed for all three probes on both alpha1V257Cbeta1gamma2 and alpha1S272Cbeta1gamma2 mutant receptors. This effect was probe concentration-dependent and could be abolished by picrotoxinin and/or t-butyl bicyclophosphorothionate. These data indicate a major interaction of non-competitive blockers at position 257 of the presumed M2 segment of rat alpha1 subunit but also suggest an interaction at the more extracellular position 272.

Animals↗

PubMed1999

Generation of the primary antibody repertoire in rabbits: expression of a diverse set of Igk-V genes may compensate for limited combinatorial diversity at the heavy chain locus.

In mouse and human, generation of combinatorial diversity through use of different heavy and light chain variable region genes in immunoglobulin rearrangements can be a major contributor to the primary antibody repertoire. In rabbits, the contribution of the combinatorial mechanism to heavy chain diversity is minimal, as only a few Igh-V genes are rearranged and expressed. To investigate the contribution of combinatorial diversity toward generation of the rabbit V(kappa) repertoire, we constructed five genomic libraries from rabbit kidney DNA and 1 cDNA library from the bone marrow of a 1-day-old rabbit using a series of polymerase chain reaction-based strategies. Our analyses indicate that most of the sequences that we recovered from our libraries belong to a single family and some are extremely similar. The actual number of germline Igk-V genes is potentially greater than our conservative estimate of at least 39, 28 of which we found expressed as mRNA. The germline Igk-V genes display different lengths of the coding region 3' of Cys 88 ranging from 7 to 12 amino acids, resulting in CDR3 length heterogeneity among functional V(kappa)J(kappa) sequences ranging from 8 to 15 amino acids. Some of the V(kappa)J(kappa) junctions had N and P nucleotide additions. Thus, in contrast to limited combinatorial diversity of its heavy chain, the rabbit can draw upon a diverse set of germline Igk-V genes. The kappa light chain has the potential to be a major contributor toward generation of the antibody specificities of the rabbit pre-immune repertoire.

Amino Acid Sequence↗

PubMed1999

Time course of the inflammatory response to histamine and allergen skin prick test in guinea-pigs.

Plasma exudation and vasodilatation are key microvascular features of acute inflammation. Exudation and vasodilatation responses in the weal area after skin prick testing with histamine are essentially completed within 30 min. There is evidence to suggest that vasodilatation lasts considerably longer after provocation with allergen, but there is no information on the duration of plasma exudation. The purpose of this study was to measure the time course of the microvascular inflammatory response in the skin after histamine and allergen provocation. Skin prick tests were performed with histamine, allergen (ovalbumin) or saline (control) on guinea-pigs which were shaved on their backs. Radioactive 113mIn was used to label transferrin as a plasma tracer. Radioactivity was recorded from the superficial part of the skin by external detection of conversion electrons from the decay of 113mIn. The increase in count rate, corresponding to tracer accumulation by vasodilatation and/or plasma exudation, was used as a measure of the microvascular inflammatory response to skin prick test. The microvascular response was studied immediately and up to 30 min after provocation. The largest response to histamine and allergen occurred immediately after provocation. The exudative response then gradually declined to be absent after 25-30 min. Skin prick test with saline resulted in a small response of shorter duration. We conclude that the microvascular reaction to histamine as well as allergen provocation in guinea-pig skin has a rapid onset and a duration of approximately 30 min.

Allergens↗

PubMed1999

Random length assortment of human and mouse T cell receptor for antigen alpha and beta chain CDR3.

In view of the recently determined three-dimensional structures of complexes formed by the T cell receptor for antigen (TCR), the processed peptide and the MHC class I molecule, it is expected that the combined configuration formed by the third complementarity determining regions (CDR3) of TCR alpha and beta chains will be very restricted in size and shape due to the limited length variations of the processed peptides. Thus, the combined TCR alpha and beta chain CDR3 lengths should have a fairly narrow distribution. This feature can be due to the selective association of long alpha chain CDR3 with short beta chain CDR3 and vice versa or due to random assortment of alpha and beta chain CDR3 of even narrower length distribution. Based on existing translated amino acid sequence data, it has been found that the latter mechanism is responsible.

Amino Acid Sequence↗

PubMed1999

Lymphocytic gastritis: association with etiology and topology.

Lymphocytic gastritis (LG) is an uncommon chronic gastritis characterized by lymphocytosis of foveolar and surface epithelium. Lymphocytic gastritis is associated with celiac disease, Helicobacter pylori (HP) gastritis, and varioliform gastritis, but its topology and severity with respect to the associated entities have not been studied in detail. Therefore, we studied 103 patients with LG classified according to the associated entities, including the distribution and severity of LG in the 70 patients from whom biopsy specimens of both antrum and body were available. In 84 patients (82%), a distinct associated entity was identified, including 39 with celiac disease, 30 with HP infection, 4 with varioliform gastritis, 2 each with inflammatory polyp, Crohn's disease, human immunodeficiency virus infection, lymphoma, and esophageal carcinoma, and 1 with lymphocytic gastroenterocolitis. Lymphocytic gastritis was found in 33% of patients with celiac disease and 4.1% of histopathologically defined HP gastritis. The severity of intraepithelial lymphocytosis was greater in antrum than in body in 83% (20 of 24) of LG associated with celiac disease, but in only 19% (4 of 21) of LG associated with HP infection (p < 0.00002). All four patients with varioliform gastritis had more severe involvement of body. Lymphocytic colitis was common (38%, 5 of 13) in celiac disease with LG. Our results indicate that lymphocytic gastritis most commonly occurs in celiac disease and HP infection, but rarely with other entities. The topology of LG can direct the clinical evaluation for associated disease.

Adolescent↗

PubMed1999

Erosive injury to the upper gastrointestinal tract in patients receiving iron medication: an underrecognized entity.

Severe gastrointestinal necrosis and strictures after an iron overdose are well described. However, mucosal injury in patients receiving therapeutic iron has received only scant recognition despite its wide use. We studied the clinical and histologic features of 36 upper gastrointestinal tract biopsies from 33 patients (24 gastric, 9 esophageal, 1 gastroesophageal junction, and 2 duodenal) containing characteristic brown crystalline iron material, and evaluated the amount and tissue distribution of the iron. In addition, we investigated the prevalence of iron-associated mucosal injury in upper gastrointestinal endoscopic examinations. The majority of the biopsies (32 of 36, 89%) contained luminal crystalline iron adjacent to the surface epithelium or admixed with luminal fibrinoinflammatory exudate. Thirty biopsies (83%) showed crystalline iron deposition in the lamina propria, either covered by an intact epithelium, subjacent to small superficial erosions, or admixed with granulation tissue. Three biopsies (8%) demonstrated iron-containing thrombi in mucosal blood vessels. Erosive or ulcerative mucosal injury was present in 30 of 36 biopsies (83%). The amount of iron accumulation in cases with mucosal injury was greater than in cases without mucosal injury (mean grades, 2.4+ vs. 1.3+ on a 1+ to 3+ scale; p = 0.002). Iron medication was confirmed in 25 of 33 patients (76%) 22 patients were receiving ferrous sulfate. Approximately half of the patients (17 of 33, 51%) also had underlying infectious, mechanical, toxic, or systemic medical conditions that could have initiated or exacerbated tissue injury. Crystalline iron deposition was found in 0.9% of upper gastrointestinal endoscopic examinations (12 of 1,300), and iron medication-associated erosive mucosal injury was present in 0.7% (9 of 1,300). These results indicate that crystalline iron deposition in the upper gastrointestinal tract is not uncommon. It can induce or exacerbate a distinctive histologic pattern of erosive mucosal injury, especially in patients with associated upper gastrointestinal disorders. Recognition of this pattern by pathologists and its communication to clinicians may aid in optimizing therapy.

Adult↗

PubMed1999

Characterization of the 5' ends for polyadenylated RNAs synthesized during the replication of hepatitis delta virus.

The genome of hepatitis delta virus (HDV) is a 1,679-nucleotide (nt) single-stranded circular RNA that is predicted to fold into an unbranched rodlike structure. During replication, two complementary RNAs are also detected: an exact complement, referred to as the antigenome, and an 800-nt polyadenylated RNA that could act as the mRNA for the delta antigen. We used a 5' rapid amplification of cDNA ends procedure, followed by cloning and sequencing, to determine the 5' ends of the polyadenylated RNAs produced during HDV genome replication following initiation under different experimental conditions. The analyzed RNAs were from the liver of an infected woodchuck and from a liver cell line at 6 days after transfection with either an HDV cDNA or ribonucleoprotein (RNP) complexes assembled in vitro with HDV genomic RNA and purified recombinant small delta protein. In all three situations the 5' ends mapped specifically to nt 1630. In relationship to what is called the top end of the unbranched rodlike structure predicted for the genomic RNA template, this site is located 10 nt from the top, and in the middle of a 3-nt external bulge. Following transfection with RNP, such specific 5' ends could be detected as early as 24 h. We next constructed a series of mutants of this predicted bulge region and of an adjacent 6-bp stem and the top 5-nt loop. Some of these mutations decreased the ability of the genome to undergo antigenomic RNA synthesis and accumulation and/or altered the location of the detected 5' ends. The observed end located at nt 1630, and most of the novel 5' ends, were consistent with transcription initiation events that preferentially used a purine. The present studies do not prove that the detected 5' ends correspond to initiation sites and do not establish the hypothesis that there is a promoter element in the vicinity, but they do show that the location of the observed 5' ends could be controlled by nucleotide sequences at and around nt 1630.

5' Untranslated Regions↗

PubMed1999

Management of stage pTxN+ adenocarcinoma of the prostate: influence of radical prostatectomy on progression-free interval.

BACKGROUND: Whether stage pN+ prostate cancer patients will benefit from radical prostatectomy remains a controversial issue. We assess the impact of radical prostatectomy on a progression-free interval for patients with stage pN+ prostate cancer. METHODS: From October 1990 to June 1997, 25 patients were diagnosed with stage pTxN+ adenocarcinoma of the prostate in our institute. Ten of these patients were treated with radical retropubic prostatectomy (RRP) due to false-negative frozen sections at staging pelvic lymphadenectomy. In 15 patients, radical surgery was discontinued because of grossly enlarged lymph nodes and/or positive frozen section results during staging pelvic lymph node dissection (PLND). All patients received immediate androgen ablation therapy with or without radiotherapy. Serum prostate-specific antigen (PSA) was regularly monitored in all patients. RESULTS: During a median follow-up period of 33 months (range, 15-89 months), eight patients (53%) in the PLND group and two (20%) in the RRP group experienced disease progression as defined by significant elevation of serum PSA concentrations. The median progression-free intervals were 46 and 51 months, respectively. Both univariate and multivariate analyses failed to show statistically significant differences in the progression-free survival between the RRP and PLND groups. CONCLUSIONS: Based on our limited experience, surgical removal of the primary tumor may have only a marginal effect in terms of the progression-free interval for prostatic cancer patients with metastasized pelvic lymph nodes (p = 0.124, log-rank test). The follow-up period was not long enough to evaluate the difference in cancer-specific survival.

Adenocarcinoma↗

PubMed1999

Pulmonary cryptococcosis: manifestations in the era of acquired immunodeficiency syndrome.

To examine the clinical manifestations, treatment, and outcome of pulmonary cryptococcosis, we reviewed the medical records of all patients treated for Cryptococcus neoformans infection at our hospital from January 1988 through September 1998. Sixty-three patients were included in the analysis, 10 (16%) of whom had acquired immunodeficiency syndrome (AIDS). Thirty-four of the 53 non-AIDS patients, including 19 men and 15 women had pulmonary cryptococcosis, including 31 with isolated pulmonary cryptococcosis and three with disseminated disease. Of the 10 AIDS patients, seven presented with disseminated cryptococcosis (including one patient with lung involvement) and one had isolated cryptococcal lung disease. The age (mean +/- SD) of the 34 non-AIDS patients with pulmonary cryptococcosis was 52.1 +/- 15.2 years (range, 19-75 yr). Cough was the most common symptom (58%). Diabetes mellitus (12%) and malignancy (12%) were two major underlying diseases. Nodules and masses were the predominant manifestations of pulmonary cryptococcosis in non-AIDS patients (79%). The most frequently used diagnostic modality for pulmonary cryptococcosis was biopsy with/without aspiration under ultrasound guidance (56%). Antifungal therapy (20/34) was the most common treatment for non-AIDS patients, followed by surgical resections with antifungal therapy (9), surgical resections alone (3), and no treatment (2). Antifungal therapy and/or resection yielded excellent outcomes (total recovery, 27; improvement, 4). Of the 18 patients who underwent lumbar puncture, only two had positive cerebrospinal fluid (CSF) cultures for C. neoformans, both had symptoms and signs of increased intracranial pressure. There was no clinical evidence of meningitis in the other 32 patients. Our findings indicate that pulmonary cryptococcosis in non-AIDS patients tends to be a more localized and benign process than in AIDS patients. Ultrasound-guided lung biopsy or aspiration is an effective tool for diagnosis. CSF examination may not be mandatory as an initial routine procedure for pulmonary cryptococcosis in non-AIDS patients.

AIDS-Related Opportunistic Infections↗

PubMed1999

Alendronate-associated esophageal injury: pathologic and endoscopic features.

Ingestion of alendronate sodium (Fosamax) by osteoporotic patients can be associated with esophagitis and esophageal ulcer. Alendronate can damage the esophagus both by toxicity from the medication itself and by nonspecific irritation secondary to contact between the pill and the esophageal mucosa, similar to other cases of "pill esophagitis." Despite its wide use, the histologic appearances of alendronate-associated esophageal ulceration have not been previously described in detail, nor is this type of medication-induced injury commonly appreciated by pathologists when evaluating biopsies from ulcer sites. We report a series of 10 patients who experienced erosive/ulcerative esophagitis while ingesting alendronate, and describe the associated endoscopic and pathologic features. Biopsies from all patients showed inflammatory exudate and inflamed granulation tissue as characteristic of any ulcer site. Polarizable crystalline foreign material was present in six of 10 biopsies (60%). Multinucleated giant cells within the inflammatory exudate were present near this crystalline foreign material in three of 10 biopsies (30%). Adjacent squamous epithelium typically showed active inflammation and a reactive appearance with enlarged, hyperchromatic nuclei. Multinucleated squamous epithelial giant cells were present in two of 10 cases (20%). Microorganisms were unusual; scattered fungi and/or viral inclusions were present in only two of 10 biopsies (20%). Recognition of alendronate-associated erosive or ulcerative esophagitis, particularly in postmenopausal women, and communication of this possibility to the clinician can improve patient care.

Aged↗

PubMed1998

Establishing human prostate cancer cell xenografts in bone: induction of osteoblastic reaction by prostate-specific antigen-producing tumors in athymic and SCID/bg mice using LNCaP and lineage-derived metastatic sublines.

LNCaP lineage-derived human prostate cancer cell lines C4-2 and C4-2B4 acquire androgen independence and osseous metastatic potential in vivo. Using C4-2 and C4-2B4 the goals of the current investigation were 1) to establish an ideal bone xenograft model for prostate cancer cells in intact athymic or SCID/bg mice using an intraosseous route of tumor cell administration and 2) to compare prostate cancer metastasis by administering cells either through intravenous (i.v.) or intracardiac administration in athymic or SCID/bg mice. Subsequent to tumor cell administration, prostate cancer growth in the skeleton was assessed by radiographic bone density, serum prostate-specific antigen (PSA) levels, presence of hematogenous prostate cancer cells and histopathologic evaluation of tumor specimens in the lymph node and skeleton. Our results show that whereas LNCaP cells injected intracardially failed to develop metastasis, C4-2 cells injected similarly had the highest metastatic capability in SCID/bg mice. Retroperitoneal and mediastinal lymph node metastases were noted in 3/7 animals, whereas 2/7 animals developed osteoblastic spine metastases. Intracardiac injection of C4-2 in athymic hosts produced spinal metastases in 1/5 animals at 8-12 weeks post-injection; PC-3 injected intracardially also metastasized to the bone but yielded osteolytic responses. Intravenous injection of either LNCaP or C4-2 failed to establish tumor colonies. Intrailiac injection of C4-2 but not LNCaP nor C4-2B4 cells in athymic mice established rapidly growing tumors in 4/8 animals at 2-7 weeks after inoculation. Intrafemoral injection of C4-2 (9/16) and C4-2B4 (5/18) but not LNCaP (0/13) cells resulted in the development of osteoblastic bone lesions in athymic mice (mean: 6 weeks, range: 3-12 weeks). In SCID/bg mice, intrafemoral injection of LNCaP (6/8), C4-2 (8/8) and C4-2B4 (8/8) cells formed PSA-producing, osteoblastic tumors in the bone marrow space within 3-5 weeks after tumor cell inoculation. A stepwise increase of serum PSA was detected in all animals. Reverse transcription-polymerase chain reaction (RT-PCR) to detect hematogenously disseminated prostate cancer cells could not be correlated to either serum PSA level or histological evidence of tumor cells in the marrow space. We have thus established a PSA-producing and osteoblastic human prostate cancer xenograft model in mice.

Animals↗

PubMed1998

Atypical splicing of the latency-associated transcripts of herpes simplex type 1.

We previously have shown that two latency-associated transcripts (LATs) of herpes simplex type 1 (HSV-1) are probably lariats, produced during splicing. By RNaseH digestion analysis, we now show that the major branchpoint of the 2.0-kb LAT was within 46 nt 5' of the splice acceptor site. A more detailed mapping by primer extension revealed the branchpoint as an adenosine 29 nt 5' of the splice acceptor site. Introduction of two branchpoint sequences with good matches to the consensus at position -25 had no effect on the splicing efficiency but reduced the accumulation of the 2.0-kb LATs at least 90-fold. The second focus of our studies was the 1.5-kb LAT. It was not detected by Northern analyses in either productively infected or transfected cultured cells or even in cells of neuronal origin. However, it was detected in the trigeminal ganglia of mice experimentally infected with HSV-1 after 10 days. Moreover, its abundance relative to that of the 2.0-kb species increased 4-fold from 10 to 30 days after infection, consistent with an interpretation that the 1.5-kb species, once formed, was more stable than the 2.0-kb species.

Animals↗

PubMed1998

Genetic alterations in Barrett esophagus and adenocarcinomas of the esophagus and esophagogastric junction region.

The incidence of esophageal adenocarcinoma has increased markedly in the past two decades, but the genetic alterations in this cancer and its precursor, Barrett mucosa, have not been characterized extensively. DNA replication errors and allelic losses of chromosomes 17p, 18q, and 5q were studied in 36 resected adenocarcinomas arising in the esophagus and esophagogastric junction, 56 Barrett adenocarcinomas, and 11 dysplasias in Barrett esophagus. The results were compared with clinical and pathological characteristics, including patient survival. Replication error positive cancer was rare (5.4%) in esophageal adenocarcinomas and was not found in Barrett mucosa. There was an increase in the prevalence of chromosomal losses in the Barrett mucosa-columnar dysplasia-adenocarcinoma sequence: 17p loss occurred in 14% of Barrett mucosae, 42% of low-grade dysplasias, 79% of high-grade dysplasias, and 75% of adenocarcinomas, respectively; loss of 18q in 32%, 42%, 73%, and 69%; and loss of 5q in 10%, 21%, 27%, and 46%. Clinical stage was a very strong prognostic factor for survival, and adenocarcinomas with allelic loss of both 17p and 18q had worse survival than cancers with no or one allelic loss (P = 0.002). Our results indicate that accumulation of genetic alterations follows the dysplasia-adenocarcinoma sequence in the esophagus and that losses of 18q and 17p occur earlier than 5q loss. Allelic loss of both 17p and 18q in esophageal adenocarcinoma identifies patients with poor prognosis.

Adenocarcinoma↗