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Biomedical subjects

P Manalo

Publications and source records attributed to P Manalo.

12 recordsLinked to original sources
PubMed2000

Tumor development and cytokine production by human colon tissues and carcinoma cell lines.

BACKGROUND AND OBJECTIVES: Solid tumors evade the host immunologic responses they initiate by unknown mechanisms. The authors investigated patterns of cytokine content in human colon carcinomas, colon cancer cell lines in vitro, and nude mouse xenografts from those lines in order to clarify those mechanisms. METHODS: Epithelial tumor cell lines were developed from specimens of human colon adenocarcinoma. Aliquots of these cells were then xenografted into female heterozygous BALB/c nu/+ immunologically deficient mice and serially passaged. Original tumors, cell lines, and resultant xenografts were then analyzed for histology/cytology and for levels of TGF-beta and TNF-alpha by enzyme linked immunoassay. RESULTS: Cytokine levels were elevated beyond baseline mucosal levels in original tumors and xenograft mouse tumors but not detectable in extracts from epithelial cultures. CONCLUSIONS: While the precise source of cytokine production remains unclear, these data suggest tumor/host interactions not found in pure epithelial cancer cells in culture.

Adenocarcinoma↗
PubMed1999

An atraumatic method to establish human colon carcinoma in long-term culture.

Techniques for creation of colon carcinoma epithelial cells lines in long-term culture have been available for years, but these techniques have involved mechanical or enzymatic methods to separate epithelial cells from surrounding tissues. While this practice has been intermittently successful, the effect of these traumatic methods on long-term cellular behavior is unknown. Samples of colon carcinoma from patient volunteers were subjected to serial nonenzymatic disruptions of carcinoma cells from surrounding fibrous tissues. Cells were collected, allowed to proliferate, and then tested for their epithelial characteristics (mucin, vimentin, cytokeratin, colon-specific antigen, carcinoembryonic antigen) by immunohistochemistry and flow cytometry. Growth characteristics were determined by phase-contrast microscopy, multiple passage, and freeze/thaw effects. Tumorigenicity was proven in nude mice. Of 11 initial attempts, three resulted in stable long-term culture lines of cells which are demonstrated to behave similarly to the original tumors from which they were derived. This technique adds another reliable in vitro tool for the study of colon carcinoma.

Adenocarcinoma↗
PubMed1996

Detection of human cells in human/sheep chimeric lambs with in vitro human stroma-forming potential.

In utero transplantation of preimmune fetal sheep with human hematopoietic stem cells results in stable long-term hematopoietic chimerism. To clarify the mechanisms of support of human stem cells in chimeric sheep, we established stromas from bone marrow of 30 sheep transplanted in utero with human hematopoietic stem cells from adult bone marrow adult peripheral blood, or fetal liver. We examined the stromas for the presence or absence of human stromal elements in vitro. Human stromal elements were detected in 12 sheep as assessed by polymerase chain reaction (PCR) using human HLA-DQalpha-specific primers. The human origin of the PCR product was confirmed by Southern blotting using an HLA-DQalpha-specific probe. However, none of these stromal cells were positive for CD45 or CD14 as determined by fluorescence-activated cell sorting (FACS) analysis or by message expression using reverse transcriptase (RT)-PCR. In an attempt to further characterize these cells fibroblasts were isolated by panning, and DNA analysis confirmed the human origin of these cells in the same lambs. Of the fetuses injected with the highly enriched cells from adult human bone marrow 36% were found to harbor cells capable of forming human stromal elements in vitro in their marrow. Of those injected with human fetal liver and peripheral blood stem cells, 42 and 40%, respectively, exhibited in vitro human stromal cell-forming ability. These results indicate the long-term persistence of cells capable of giving rise to components of human marrow stroma in vitro in the human/sheep xenograft model.

Animals↗
PubMed1993

Confirmation of the association of human papillomavirus with human colon cancer.

The human papillomavirus (HPV) has been shown to be associated with neoplasms of the human colon using immunohistochemistry and in situ hybridization. We now report our use of the polymerase chain reaction and Southern blotting to investigate that same association. We selected 38 carcinomas, 21 adenomas, and 24 normal mucosal samples for the current study. Tissue sections were prepared, and then DNA was extracted and subjected to 40 cycles of amplification using Thermus aquaticus DNA polymerase and a set of degenerate primers. Amplified products were analyzed by agarose gel electrophoresis and Southern blotting. The L1 region of the HPV genome was identified in 13 of 38 carcinomas (32%), 8 of 21 adenomas (38%), and 2 of 24 normal biopsy specimens (8%). These observations validate our previous results and confirm the presence of HPV in human colon mucosa and tumors of that mucosa.

Adenoma↗
PubMed1990

Association of human papillomavirus and colon neoplasms.

Human papillomavirus has been shown to be associated with squamous carcinomas. We evaluated benign and malignant colon tissues for the presence of human papillomavirus infection to determine if a similar relationship exists between human papillomavirus and colon neoplasms. Colon tissues were screened using an immunohistochemical technique to detect human papillomavirus antigen. In situ DNA hybridization was then performed on those tissues that yielded positive results by immunohistochemistry. Groups were compared using chi 2 analysis. Human papillomavirus antigen was present in 23% of normal colon specimens, 60% of benign tumors, and 97% of carcinomas. Human papilloma viral genome was demonstrated in 27% of benign tumors and in nearly 43% of all carcinomas tested. These data indicate that human papillomavirus infects the columnar mucosa of the colon, and that an association exists between human papillomavirus and colon neoplasia.

Adenoma↗
PubMed1990

Immunohistochemical demonstration of human papilloma virus antigen in human colon neoplasms.

The presence of human papilloma virus (HPV) has recently been demonstrated in colon tumors, but the incidence of HPV infection in normal colon mucosa or in benign or malignant neoplasms of the mucosa is unknown. We studied both neoplastic and normal human colon tissue for the presence of HPV antigen using immunohistochemical techniques. Ninety colon specimens were studied. Three consecutive series of normal colon mucosa (N = 30), single benign tubulovillous adenomas (N = 30), and invasive carcinomas (N = 30) were selected and confirmed histologically. Formalin-fixed paraffin-embedded samples of each tissue were prepared using immunohistochemical techniques and resultant slides were read blindly and graded simply as positive or negative for HPV antigen. The presence of HPV antigen varied dramatically between groups, with 97% of the invasive carcinomas, 60% of the benign tubulovillous adenomas, and 23% of the normal mucosa positive for HPV antigen. Groups were statistically significant using chi 2 analysis (P less than 0.001). We conclude that an association exists between the human colon neoplasia and the presence of HPV antigen. This may suggest an etiologic role of the virus in colon cancer.

Adenoma↗
PubMed1987

Human cytomegalovirus infection of human placental explants in culture: histologic and immunohistochemical studies.

The induction of human cytomegalovirus infection in human first-trimester placentas was studied with a placental explant culture model. Replication and/or release of human cytomegalovirus in placental explant cultures did not occur at any time from 1 to 10 days after infection when examined by plaque assay and analyses of extracted deoxyribonucleic acids. In contrast, typical human cytomegalovirus-induced histopathologic lesions bearing human cytomegalovirus antigens were consistently localized in the trophoblastic cells covering placental villi. These data clearly demonstrate that placental cells are permissive of latent and/or abortive human cytomegalovirus infection in vitro. Our results support the hypothesis that during human cytomegalovirus infection of pregnant women, maternal viremia or intrauterine infection results in latent human cytomegalovirus infection of placental cells that may persist during the course of pregnancy.

Antigens, Viral↗
PubMed1982

Aspirin and dipyridamole inhibit endothelial healing.

Aspirin and dipyridamole have been used to treat the thromboembolic complications of atherosclerosis. We studied the effects of these drugs on the rate of endothelial healing after a standard de-endothelializing injury of the thoracic aorta. Twenty-five rabbits received 13.5 mg/kg/day of aspirin and 15 mg/kg/day of dipyridamole one week before injury and for the period of endothelial regrowth. There were 25 control animals. Mean serum aspirin salicylate levels were 12 micrograms/dL at the time of injury and 15 micrograms/dL at death. Areas of endothelial regrowth were measured by Evans blue dye at 1, 4, 7 and 14 days after injury. The percentage of endothelial regrowth was measured by computer-assisted morphometry. Antiplatelet treatment retarded endothelial regrowth by 66% at four days, 22% at seven days, and 28% at 14 days. Antiplatelet drugs must be used cautiously, as re-endothelialization of injured arteries is retarded.

Animals↗
PubMedDate not supplied

Persistence of human cytomegalovirus DNA sequences without cell-virus homology in human placental explants in culture.

Using histopathology, virology, and molecular probing, we investigated the potential of human first-trimester placental tissue to support human cytomegalovirus (HCMV) infection. Histopathologic examination of infected placental explants revealed cellular changes characteristic of HCMV infection. Immunohistochemical staining of infected explants with human convalescent sera demonstrated expression of HCMV antigens within the cytotrophoblast. Dot blot hybridization of DNA extracted from infected placental tissue using cloned Hind III "W" fragment of HCMV genome indicated the presence of HCMV sequences without virus-cell homology in infected explants from one to ten days post-infection. In general, the sequences detected by the viral probes increased in abundance with time as infection continued.

Antigens, Viral↗
PubMedDate not supplied

Cytologic findings in signet-ring adenocarcinoma of the large bowel. A case report.

Signet-ring adenocarcinoma of the large bowel is an uncommon tumor with distinctive gross anatomic, radiologic and histologic features. A case in a 34-year-old man is presented. Because of the unusual appearance of the bowel at colonoscopy, diagnostic cytologic smears were taken. The patient subsequently underwent resection of this tumor but died within 20 months of metastatic disease. The histologic and cytologic features are described; the cytologic findings do not appear to have been previously reported.

Adenocarcinoma, Mucinous↗