Biomedical subjects

M Mohiuddin

Publications and source records attributed to M Mohiuddin.

149 records · Page 9Linked to original sources

PubMedDate not supplied

Rectal cancer: extent of disease and radiotherapeutic effects by computed tomography.

The CT scans of 54 patients with carcinoma of the rectum were studied in an attempt to assess the value of computed tomography in the initial evaluation and therapeutic management of these patients. Thirty-five of the examined patients received full dose preoperative radiation therapy for sphincter preservation purposes, and had two or more computed tomography studies to delineate the progression of the disease and the response to radiotherapy. In 70% of these patients, changes in tumor size were demonstrated. Various aspects in the CT diagnosis of the primary or recurrent tumor extent, distant metastatic spread or involvement of surrounding tissues are discussed.

Adenocarcinoma↗

PubMedDate not supplied

Reproduction of radiologic images on plain paper.

Skyrocketing health care costs and pressures from managed care have combined to promote cost-cutting strategies in radiology and radiation oncology departments. A study was conducted to evaluate the use of a high-resolution laser printer for printing plain-paper images as substitutes for both original and duplicate radiologic film images. A variety of radiologic images were used to evaluate the image reproduction capabilities of the printer in terms of linearity, detail, and contrast. In many cases, printed images had a quality comparable to that of the original images. Six computed tomographic (CT) scans and six radiation therapy simulator radiographs were compared with printed reproductions by each of seven board-certified radiation oncologists, who rated the reproductions as acceptable for documentation, acceptable for diagnostic purposes (CT scans only), or unacceptable. Ninety-five percent of printed CT images and 90% of printed simulation images were rated acceptable for documentation. The quality of printed images of radiation therapy port films was not quantitatively measured but was improved by adjusting image contrast and brightness and using various image enhancement techniques. The use of printed images is less expensive than that of processed film and eliminates the environmental, time, storage, and delivery problems associated with film. Technologic advances in imaging, networking, and printing have made possible the inexpensive duplication of medical images.

Copying Processes↗

PubMedDate not supplied

Differential expression of transforming growth factor beta receptors in human pancreatic adenocarcinoma.

BACKGROUND: Many cancer cells show resistance to transforming growth factor beta (TGF-beta)-mediated growth inhibition. This resistance to TGF-beta is associated with an increased tumorigenic phenotype. OBJECTIVE: In this study, we determined whether a loss in expression of TGF-beta receptors or DPC4, an important down stream target of TGF-beta signaling, might account for this lack of TGF-beta sensitivity in pancreatic adenocarcinoma. MATERIALS AND METHODS: To accomplish this, six established pancreatic cancer cell lines, twenty-six surgically resected tumor specimens of pancreatic adenocarcinoma and ten non-tumor pancreas tissues were analyzed for the mRNA expression of the three TGF-beta receptors (RI, RII, and RIII) and DPC4. RESULTS: We report here that five of six pancreatic cancer cell lines were not sensitive to TGF-beta. All the ten non-tumor specimens of pancreas showed expression of RI, and DPC4; while nine of ten showed expression of RIII and eight of ten showed expression of RII. Five of six pancreatic cancer cell lines and 23 of 26 tumor specimens showed expression of RI. Two cell lines and about half (46%) of the tumor specimens did not express RII. Only two cell lines showed appreciable levels of RIII expression; while ten of 26 (38%) tumor specimens did not show expression of RIII. DPC4 expression was observed in three of the six (50%) cell lines and 19 of 24 (79%) tumor specimens. CONCLUSION: This study indicates that apart from the functional loss of DPC4 due to mutations or homozygous deletion, a lack of the TGF-beta receptors, particularly RII and RIII, may contribute to a loss of TGF-beta signaling in a population of pancreatic cancers.

Activin Receptors, Type I↗

PubMedDate not supplied

Low dose preoperative radiation in the treatment of carcinoma of the rectum.

Recent advances in the treatment of cancer of the rectum show a steady improvement in survival. Newer surgical techniques and expanding options for adjunctive therapy appear to have had a significant impact on improving both local control and distant disease. Five-year survival of patients now ranges from 85-90% for stage I cancers and 50-55% for stage III cancers. Local recurrence of disease following curative surgical resections is dependent on the stage of the tumor and for some high-risk patients, stages T3/T4 and N+ disease, has been reported as high as 40-60%. In an attempt to lower the rate of local recurrence and improve survival, several approaches to adjuvant therapy have been utilized. Preoperative radiation was one approach that has been used extensively in the last decades. Recently, the large Swedish randomized studies using a short course (5 Gy x 5) of preoperative radiation have reported a clear improvement in local control and survival of patients. These results were achieved with no downstaging of disease since surgery was performed put immediately after irradiation. Therefore it should be presumed that preoperative radiation therapy resulted in the sterilization of tumor cells, which prevented both local and distant dissemination leading to the improved outcome. The question remains, therefore, as to what is the least and/or the most appropriate dose of preoperative irradiation that can achieve the beneficial effect of minimizing tumor cell dissemination at surgery. Low dose preoperative irradiation as a single fraction of 500 cGy appears to have a sound biological basis and in single institutional studies it was shown to be effective but in randomized studies it did not improve results. This is likely to be due to a poor design of trials and/or inappropriate patient selection for these studies. A well-designed study still remains to be done.

Humans↗

PubMedDate not supplied

Successful experimental heart transplantation without immunosuppressive drugs.

Donor-specific unresponsiveness is an important goal of heart transplantation research. Work by other investigators has shown that intrathymic transplantation of pancreatic islet cells not only leads to factor permanent acceptance of the intrathymic graft but tolerance to subsequent extrathymic islet cell transplants. We applied this concept to a model of heart allotransplantation in the rat. Recipient Lewis rats were treated with 1 ml of antilymphocyte serum and 5 x 10(7) Lewis-Brown Norway spleen cells injected into the thymus under direct vision. Twenty-one days later, heterotopic heart transplantation was performed with Lewis-Brown Norway (allograft) and Wistar-Furth (third-party allograft) donors. Control Lewis recipients received no treatment, antilymphocyte serum alone, or antilymphocyte serum plus intrathymic syngeneic Lewis spleen cells. Another group of animals received intravenous Lewis-Brown Norway cells before transplantation with Lewis-Brown Norway heart donors. Untreated control animals had heart graft survival of 6 to 10 days (mean, 7.6 days) and 7 to 9 days (mean, 7.8 days) for Lewis-Brown Norway (n = 5) and Wistar-Furth (n = 5) donors, respectively. Antilymphocyte serum alone (n = 10) failed to prolong survival of Lewis-Brown Norway grafts (mean, 10.7 days; p = not significant). Antilymphocyte serum plus intrathymic Lewis cells (n = 5) did not prolong survival of a subsequent Lewis-Brown Norway graft (mean, 9.2 days; p = not significant). Survival of Wistar-Furth third-party allografts (n = 10) was not prolonged by intrathymic Lewis-Brown Norway cells (mean survival, 13.9 days; p = not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗