Biomedical subjects
D Mullen
Publications and source records attributed to D Mullen.
Surface roughness enhances upward migration of bacteria on polymer fibers above liquid cultures.
Monofilament polypropylene (PP) fibers, very similar to fibers that have been used as monofilament tailstrings of interuterine contraceptive devices, were suspended vertically in bacterial liquid monocultures so that a portion of a fiber extended above the liquid surface. In some cases these highly oriented, cold drawn fibers were abraded prior to insertion in the cultures in order to produce surface roughness characterized by axial channels and protruding microfibrils that partially peeled from the fiber surface thereby forming the channels. Extent of migration on a fiber was assessed by aseptically cutting it into small segments, followed by culturing each segment on agar containing growth medium. Such assessment of the PP fibers after 48 h of incubation in the cultures revealed upward migration of Eschericia coli, Pseudomonas aeruginosa, and Staphylococcus aureus over significantly longer distances on the pre-roughened fibers than on those not so pre-treated. Mean measured distances of migration during 48 h were: for E. coli 2.7+/-0.6 mm on roughened fibers (n = 16) and 0.4+/-0.7 mm on fibers not roughened (n = 17); for S. aureus 9.0+/-4.3 mm on roughened fibers (n = 13) and 0.2+/-0.3 mm on fibers not roughened (n = 14); for P. aeruginosa 8.5+/-3.7 mm on roughened fibers (n = 26) and 0.2+/-0.5 mm on fibers not roughened (n = 5). Although no statistically significant (95% confidence level) difference could be discerned between the migration distances of S. aureus and P. aeruginosa, each of these species migrated a greater distance on the PP than did E. coli. The migrations observed are attributed predominantly to wicking of the liquid cultures upward in the axial grooves developed on the surface of the PP by the eruption and peeling of microfibrils from the surface. Surface tension of the growth medium was significantly lower than that of water and its contact angle on PP was less than 90 deg, thereby indicating a tendency to wet the PP. Bacterial growth in the medium further reduced its contact angle on PP, thereby indicating an even greater tendency to wet PP after such growth.
Design and synthesis of novel cyclic RGD-containing peptides as highly potent and selective integrin alpha IIb beta 3 antagonists.
Utilizing conformational constraints in conjunction with various structural considerations, we have synthesized a series of cyclic disulfide peptides that are highly potent and selective antagonists for the platelet integrin alpha IIb beta 3 (GPIIb/IIIa). The affinities of the peptides for alpha IIb beta 3 were determined by platelet aggregation assays and an alpha IIb beta 3 ELISA. Their affinities for alpha 5 beta 1 and alpha v beta 5 integrins were also determined in respective ELISA assays. Structure-activity relationship studies suggest that R-G-D-Ar-R (Ar = hydrophobic residue) is the essential pharmacophore that is responsible for their high alpha IIb beta 3 binding affinity, very high selectivity, and distinct biological properties. One of these analogues, TP9201, has been shown to inhibit platelet-mediated thrombus formation without associated prolongation of template bleeding time. The arginine residue adjacent the carboxy terminus of the R-G-D-Ar sequence could function as the biological effector element that determines this distinct and unexpected biological property.
Combined iodine-125 plaque irradiation and indirect ophthalmoscope laser therapy of choroidal malignant melanomas: comparison with iodine-125 and cobalt-60 plaque radiotherapy alone.
The authors studied the short-term impact of combined episcleral iodine-125 plaque radiotherapy and argon laser treatment in a series of 24 patients with choroidal malignant melanoma. All patients underwent plaque therapy prior to their initial laser session. All laser treatments were performed with an indirect ophthalmoscope argon green laser, using low-power, long-duration exposures. The endpoint of laser therapy was a well-defined atrophic circumbasal chorioretinal laser scar and complete or nearly complete nonfluorescence of the lesion on fluorescein angiography. In a case-by-case matched comparison study, the authors evaluated the relative local regression of tumors treated by combined plaque-laser therapy, iodine-125 plaque therapy alone, and cobalt-60 plaque therapy alone. The tumors treated with supplemental laser regressed substantially faster and more completely than did those treated by either type of plaque therapy alone. However, the short-term visual loss was greater in eyes treated by the combined therapy.
Planned combined I-125 plaque irradiation and indirect ophthalmoscope laser therapy for choroidal malignant melanoma.
We studied the short-term impact of planned sequential episcleral I-125 plaque irradiation and indirect ophthalmoscope laser therapy in a series of 25 patients with choroidal or ciliochoroidal malignant melanoma. In a case-by-case matched comparison study, we evaluated the relative local regression of tumors which did and did not receive planned supplemental laser therapy following plaque treatment. The tumors treated with supplemental laser regressed substantially faster and more completely than those treated by plaque alone. Planned sequential I-125 plaque irradiation combined with indirect ophthalmoscope laser therapy appears to be a more effective local-tumor treatment than plaque radiotherapy alone.
Indirect ophthalmoscope laser treatment as supplement to 125I plaque therapy for choroidal melanoma.
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Endometrial carcinoma: clinical-pathologic comparison of cases in postmenopausal women receiving and not receiving exogenous estrogens.
Clinical and pathologic findings were compared in 43 postmenopausal endometrial carcinoma patients who had received exogenous estrogens prior to diagnosis and 79 similar patients unexposed to estrogens. Estrogen non-users were more likely to manifest lower parity, later menopause, obesity, hypertension, and diabetes, all of which have been considered to be constitutional risk factors for the development of endometrial carcinoma. Although estrogen users and non-users had similar extent of disease as judged by clinical stage, there was a tendency to more myometrial invasion in hysterectomy specimens from non-users, as well as greater frequency of unfavorable histologic types and grades of tumor. At short-term follow-up, more recurrences occurred in non-users, and this tendency appeared to be independent of clinical stage, histologic type, histologic grade, or modality of treatment. The significance of these and other observation to the determination of the risk-benefit ratio for estrogen administration is discussed.
Caloric restriction lowers blood pressure in the spontaneously hypertensive rat.
In the spontaneously hypertensive rat (SHR), caloric restriction without sodium restriction is associated with reduced blood pressure. Four days of fasting lowered blood pressure 19% while 4 days of eating 50% of ad lib intake reduced blood pressure 10%. Similar dietary changes had less effect on blood pressure in normotensive rats of the same strain (Wistar-Kyoto--WKY). These data are consistent with the hypothesis that caloric restriction lowers sympathetic activity.
Coronary cineangiography and coronary artery grafting.
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Diagnostic-therapeutic intake groups for wives of alcoholics.
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Leiomyoblastoma: varied CT appearance.
Leiomyoblastoma is an uncommon tumor of the stomach. Usually exogastric in site, the tumor may grow to a significant size before it becomes symptomatic. Various appearances of the tumor include cystic and solid forms as well as a combination of both. Tumor hypervascularity may be identified on computed tomography (CT). The development of calcification in this tumor is rare. Late recurrence of the tumor may occur. The differential diagnosis should include leiomyosarcoma, leiomyoma, pancreatic pseudocyst, and cystadenoma.