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Biomedical subjects

C B Bagwell

Publications and source records attributed to C B Bagwell.

12 recordsLinked to original sources
PubMed1992

Nuclear DNA analysis of hyperplastic parathyroid glands in multiple endocrine neoplasia type I.

Twenty-four hyperplastic parathyroid glands from 11 patients with multiple endocrine neoplasia type I (MEN-I), and 36 hyperplastic parathyroid glands in 15 patients with sporadic primary hyperparathyroidism, ie, not associated with MEN, were analyzed for DNA by flow cytometry. Sixteen of 24 hyperplastic parathyroid glands from patients with MEN-I were DNA diploid, and eight were DNA aneuploid. Thirty-three of 36 hyperplastic parathyroid glands from patients without MEN were DNA diploid, and only three were DNA aneuploid. The mean percentage of 4c level (a measure of the G2M phase of the cell cycle) of DNA diploid hyperplastic parathyroid glands taken from patients with MEN-I was 8.1% +/- 4.5%, which is significantly higher than the 3.5% +/- 3.4% for those taken from patients without MEN. Our results show that there is a difference in nuclear DNA content between hyperplastic parathyroid glands in patients with MEN-I and those in patients without MEN.

Aneuploidy↗
PubMed1992

DNA signal splitting improves detection and analysis of tetraploid populations.

Detection of DNA tetraploid populations requires a high index of suspicion at the time of data acquisition and frequently requires subsequent off-line analysis for confirmation, including evaluation of the hypertetraploid region. To analyze these specimens, the flow cytometer operator must run all specimens with the G0G1 peak in low channels or rerun specimens in which tetraploidy is suspected with a lower photomultiplier tube (PMT) voltage or lower amplifier gain setting. Re-analysis may not be possible in specimens with few cells. A simple modification to the cytometer allows PMT signal splitting with simultaneous processing of the signal by two different amplifiers. This allows simultaneous acquisition of histograms optimized for both the hypotetraploid and hypertetraploid regions.

DNA, Neoplasm↗
PubMed1979

Differences in flow cytometry and 3H-thymidine analyses of perturbed human lymphocytes.

A calf thymocyte crude aqueous extract was tested for DNA synthesis inhibitory activity using phytohemagglutinin-stimulated human peripheral blood lymphocytes. Inhibition of DNA synthesis was assayed using tritiated thymidine and flow cytometry. Although the calf thymocyte crude extract inhibited tritiated thymidine incorporation by over 50%, only very slight changes in the flow cytometric analysis were observed. When dibutyryl-cyclic adenosine monophosphate was used as an inhibitor, a correlation in terms of the inhibition of tritiated thymidine to the inhibition by flow cytometry was observed.

Animals↗
PubMed1979

Nonparametric flow cytometry analysis.

A nonparametric statistical test for the analysis of flow cytometry derived histograms is presented. The method involves smoothing and translocation of data, area normalization, channel by channel determination of the mean and S.D., and use of Bayes' theorem for unknown histogram classification. With this statistical method, different sets of histograms from numerous biological systems can be compared.

Cells, Cultured↗
PubMed1979

Multiparameter kinetic analysis of killer cell initiation by using immune RNA.

By treating nonsensitized C57BL/6J spleen derived lymphocytes with EL-4 tumor cell directed xenogeneic extracted RNA we were able to monitor early changes in cellular DNA content by flow cytometric (FCM) analysis and 3H-thymidine uptake. These kinetic parameters were correlated with cell mediated cytotoxicity which appeared as early as 8 hr after activation as measured by release of chromium-51 from labeled EL-4 target cells. Flow cytometric analysis and 3H-thymidine uptake data shown peak S phase activity at 72 hr. Maximum cytotoxicity was observed at 48 hr. Cell cycle kinetic parameters were correlated with the appearance of cell mediated cytotoxicity.

Animals↗
PubMed1978

Inhibition of growth and guanylate cyclase activity of an undifferentiated prostate adenocarcinoma by an extract of the balsam pear (Momordica charantia abbreviata).

We have recently described the presence of a guanylate cyclase [GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2] inhibitor (GCI) in an aqueous extract of the balsam pear (Momordica charantia abbreviata). Because the guanylate cyclase-cyclic GMP system is though to be involved in cell growth, DNA and RNA synthesis, and possible malignant transformation, we examined the effect of the aqueous extract containing GCI on an undifferentiated adenocarcinoma of the rat prostate and concanavalin-A-stimulated [3H]thymidine incorporation into cultured splenic lymphocytes, a process thought to be mediated by cyclic GMP. The results demonstrate that the extract of the balsam pear blocks both the growth of the rat prostatic adencarcinoma in vitro and [3H]thymidine incorporation into DNA. DNA histograms from flow cytometry indicated that the extract containing GCI inhibited in the G2 + M phase of the cell cycle, a presumed locus of cyclic GMP effects. In addition, guanylate cyclase activity was significantly greater in the tumor than normal prostate tissue and was decreased by the extract containing GCI. Cyclic GMP levels in the tumor in culture wer also decreased by addition of the extract. It remains to be determined whether or not the anti-tumor agent and GCI are the same substance.

Adenocarcinoma↗
PubMedDate not supplied

Single and multigland disease in primary hyperparathyroidism: clinical follow-up, histopathology, and flow cytometric DNA analysis.

Two-hundred seventy-four patients with primary hyperparathyroidism had selective removal of enlarged parathyroid glands. Biopsies were taken from all parathyroid glands. Normal-size glands were not resected irrespective of their histological appearance. After a mean follow-up of 13.5 years the rates of persistent and recurrent hyperparathyroidism were, respectively, 3.6% and 0.7%. Transient and permanent hypoparathyroidism occurred in 24% and 2.5% of the patients. The microscopic appearance of enlarged glands and of biopsies taken from normal-size glands were reviewed by two pathologists. Normal parathyroid glands were distinguished from abnormal glands fairly accurately (sensitivity 93%, specificity 80%). Microscopic classification of abnormal parathyroid glands as adenomas or hyperplastic glands correlated poorly with the gross classification as single or multigland disease. Flow cytometric DNA analysis of paraffin embedded parathyroid tissue showed significant differences for DNA index, % S-phase and % G2M (p less than 0.001). Differentiating single from multigland disease by means of DNA analysis was not possible. In conclusion, removal of only enlarged parathyroid glands results in acceptable rates of persistent and recurrent hyperparathyroidism. Biopsies should only be taken sparingly to prevent transient and permanent hypoparathyroidism. Microscopic examination and flow cytometric DNA analysis can differentiate normal from abnormal parathyroid glands but are unable to differentiate abnormal glands into single or multigland disease.

Adolescent↗