Biomedical subjects

J Demers

Publications and source records attributed to J Demers.

13 recordsLinked to original sources

PubMed1995

DNA ploidy of hydatidiform moles and nonmolar conceptuses: a study using flow and tissue section image cytometry.

This study was performed to investigate the role of DNA cytometry in the evaluation of molar and nonmolar pregnancies. DNA ploidy analysis was performed on paraffin-embedded tissue from 53 molar (35 complete, 18 partial) and 24 nonmolar (13 hydropic, 11 nonhydropic) conceptuses. Nuclear suspensions were analyzed by both flow and image cytometry and there was excellent correlation (96%) in the classification of DNA diploid, triploid, and tetraploid cases using these two methods. DNA ploidy analysis revealed a high proportion of tetraploid nonmolar conceptuses (42%) and complete moles (47%). The majority of partial moles were triploid (89%). Tissue sections from all cases were also studied by image cytometry to identify the cellular subpopulations (decidua, villous stromal cells, inner trophoblast, and extravillous trophoblast) with abnormal DNA content. In the triploid cases, all of the villous cell subtypes had an abnormal DNA content consistent with the development of partial moles from a triploid conceptus. In contrast, the majority of tetraploid cases showed high proliferative activity of the extravillous trophoblast whereas the other villous cell subtypes were diploid. These results suggest that tetraploid complete moles may arise from a diploid conceptus with the development of tetraploidy related to polyploidization of the hyperplastic extravillous trophoblast. Tissue section image cytometric DNA analysis can aid in our interpretation of ploidy results and our understanding of the biology of molar pregnancies.

Cell Nucleus↗

PubMed1994

DNA image cytometry of prostatic carcinoma: a comparison of needle core biopsy and subsequent prostatectomy specimens.

DNA ploidy has recently been identified as an objective prognostic factor in prostatic carcinoma. Although the diagnosis of prostatic carcinoma is increasingly being made with the use of needle core biopsies, the optimal method for the cytometric analysis of these specimens has yet to be determined. In addition, the degree to which the biopsy is representative of the subsequent prostatectomy specimen with respect to DNA heterogeneity has not been adequately addressed. In this study, image cytometric (ICM) DNA analysis was performed on tissue sections from 12 prostatic needle core biopsies and the results were compared with similar ICM analysis of the subsequent prostatectomy specimens. Multiple blocks (n = 48) of the prostatectomy specimens were utilized to prepare tissue sections and nuclear suspensions and each set of preparations were analyzed by ICM in a parallel comparison study. There was concordance of 0.80 in the classification of DNA diploid and aneuploid tumors by ICM analysis of tissue sections and nuclear suspensions from paraffin blocks. In all of the discordant cases, DNA aneuploid populations were identified by ICM analysis of tissue sections only. This is attributed to difficulties in obtaining a representative nuclear suspension from disaggregated paraffin-embedded prostatic tissue which often has a very desmoplastic stroma. ICM analysis of tissue sections seems to be an optimal method for DNA ploidy analysis of prostatic carcinoma and is well suited to small volume biopsy material. Determination of DNA ploidy status in prostatic biopsies was predictive of the subsequent prostatectomy specimens with a concordance of 0.92.

Aged↗

PubMed1986

An explanation for nonimmunologic adsorption of proteins onto red blood cells: Schiff's base reactions.

During a phase I evaluation of diglycoaldehyde (INOX), an intravenous chemotherapeutic agent used to treat children with malignancies, all of eight patients tested developed a positive direct antiglobulin test (DAT) in vivo. The DAT became positive within one to seven days after the first administration of the drug and remained positive for up to 12 days following the last dose. The indirect antiglobulin tests were negative. None of the patients showed clinical or laboratory evidence of hemolysis at the time the DAT became positive or during follow-up. Eluates made from the red cells of two of the eight patients were both negative by indirect antihuman globulin testing. In vitro studies with INOX and glutaraldehyde, both dialdehyde compounds, showed nonimmunologic adsorption of protein onto red cells, probably by the condensation of aldehyde groups of these compounds to form Schiff's bases with amino acids of serum proteins and red cell membrane proteins. This reaction provides an explanation for the globulin detected on the red cells of patients treated with INOX.

Adolescent↗

PubMed1984

Yolk sac tumor of the testicle: is retroperitoneal lymph node dissection necessary?

We report our experience with 11 cases of yolk sac tumors, which were treated between 1960 and 1982 at the Hôpital Sainte-Justine and the Montreal Children's Hospital. The role of lymphadenectomy in yolk sac tumors is analyzed critically and put into perspective with the use of serum alpha-fetoprotein. A flow sheet is presented for the management of yolk sac tumors. It seems that the indication for lymphadenectomy in yolk sac tumor should be restricted to patients with persistently elevated serum alpha-fetoprotein after inguinal orchiectomy and chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1984

Trilateral retinoblastoma: bilateral retinoblastoma with pinealoblastoma.

Bilateral retinoblastoma was diagnosed in a 12-month-old boy. The left eye was enucleated; the choroid and the optic nerve were not invaded by the tumour. The right eye had three lesions: one was photocoagulated, and the other two were irradiated. Two years later, symptoms and signs of intracranial hypertension prompted computerized tomography, which demonstrated a mass in the pineal region and secondary hydrocephalus. The right eye showed papilledema but no evidence of tumour activity in the three retinal scars. Radiation therapy and chemotherapy had only a transient effect, and the child died at 42 months of age. At autopsy the pineal region and the third ventricle were found to be replaced by a pinealoblastoma with retinomatous differentiation. Only 11 other cases of pinealoblastoma associated with bilateral (heritable) retinoblastoma have been reported. The embryologic relationship between the pineal gland and the retina has given rise to the concept of trilateral retinoblastoma, a concept important in the investigation and follow-up of patients with bilateral retinoblastoma.

Brain Neoplasms↗

PubMed1983