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Biomedical subjects

E D Allen

Publications and source records attributed to E D Allen.

At least 55 records · Page 3Linked to original sources
PubMed1988

Induction of annulate lamellae by alpha-difluoromethylornithine in P3J, a Burkitt's lymphoma cell line.

Annulate lamellae form in P3J, a Burkitt's lymphoma cell line, treated with alpha-difluoromethylornithine (DFMO), an inhibitor of polyamine synthesis. DFMO (50-100 micrograms/ml) prevents proliferation although cells remain viable. Upon exposure to DFMO, lamellae with a few pores form within 2-3 days and well-developed stacks of annulate lamellae in 5-6 days. Formation of annulate lamellae involves the addition of electron-dense fibrous material to cisternae of the endoplasmic reticulum while the latter are in close association with the Golgi complex. Addition of the polyamine putrescine to DFMO-treated cells reverses the inhibition of cell proliferation caused by DFMO. Following recovery from DFMO treatment, P3J cells appear similar to untreated ones in that they do not possess stacks of annulate lamellae.

Burkitt Lymphoma↗
PubMed1986

Effect of alpha-difluoromethylornithine alone and in combination with doxorubicin hydrochloride, cis-diamminedichloroplatinum (II), and vinblastine sulfate on the growth of P3J cells in vitro.

alpha-Difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase, was examined as a single and combined agent in growth studies using P3J, a Burkitt's lymphoma cell line. Used alone, DFMO (greater than or equal to 50 micrograms/ml; 0.21 mM) prevents cell proliferation in liquid culture and reduces the number and size of colonies that form in a two-layer soft agar system. In combination studies in which the soft agar system was used, DFMO was used at 15 and 25 micrograms/ml, concentrations which reduced the number of colonies to approximately 65 and 50%, respectively, of control plates. When doxorubicin hydrochloride (Adriamycin) was combined with DFMO, synergistic effects were noted at both DFMO concentrations. Cisplatin and DFMO were synergistic at the higher DFMO concentration and were supraadditive at 15 micrograms DFMO/ml. Combination studies using vinblastine sulfate (Velban) with DFMO did not deviate significantly from the predicted additive response.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

Argon laser trabeculoplasty or trabeculectomy a prospective randomised block study.

A prospective randomised block study of treatment by either argon laser trabeculoplasty or trabeculectomy was undertaken in patients with chronic open angle glaucoma not controlled by medication. The study was undertaken in two centres in the United Kingdom where the regimes of medical treatment prior to interference were different. Regression analysis showed that in both populations laser trabeculoplasty was effective in reducing the intraocular pressure but it was less effective than trabeculectomy in permanently reducing the intraocular pressure to within normal limits. Laser trabeculoplasty was most effective in those patients whose intraocular pressure was initially high but many of these required post-operative medication or surgery. Laser trabeculoplasty is a useful adjunct to the therapy of open angle glaucoma but it is not a substitute for trabeculectomy as a method of permanently reducing the intraocular pressure to normal. Because of the effectiveness of both these methods of treatment we feel it no longer justified to use anything other than simple local medication to control the intraocular pressure before proceeding to active therapy.

Adult↗
PubMed1984

In vitro colony formation by cryopreserved primary human tumor cells.

The effect of cryopreservation on the ability of primary human cancer cells to form colonies in a two-layer agar system was examined. Although considerable variation occurred, concentrations of 5 or 10% dimethylsulfoxide employed with slow freezing rates allowed survival of colonies in the range 20-40% or greater of nonfrozen controls. The methods used in this study do not require elaborate freezing equipment, and can be used for the cryopreservation of a wide variety of types of cancers.

Colony-Forming Units Assay↗
PubMed1983

Role of contact lenses in the management of congenital nystagmus.

Congenital idiopathic nystagmus is usually associated with poor vision which has generally proved resistant to treatment. This study reports the use of contact lenses in 8 patients, 5 of whom achieved an improvement in their visual acuity of 3 lines on the Snellen's chart.

Adolescent↗
PubMed1980

The congenital warfarin syndrome: a case report.

A case is reported of a baby born with congenital abnormalities due to maternal ingestion of warfarin during pregnancy. Warfarin is known to be teratogenic, producing characteristic abnormalities, namely a hypoplastic nose, stippled epiphyses, and skeletal abnormalities. A variety of ocular abnormalities have been reported. Ophthalmologists should seek a history of maternal warfarin ingestion when seeing a baby with congenital ocular abnormalities. They should also be aware of the possible teratogenic effects when considering warfarin therapy for a woman of childbearing age.

Abnormalities, Drug-Induced↗
PubMed1979

Ultrastructure of red cells frozen with hydroxyethyl starch.

The freeze fracture appearance of red cells frozen in the presence of varying concentrations of hydroxyethyl starch (HES) is described. A technique is used which allows examination of a small portion of cells from a larger unit. The frozen cells appear distorted probably as a result of osmotic dehydration but indicate no evidence of intracellular ice. The frozen mixture with HES has three phases--a particulate phase consisting of the concentrated HES (and other salts), a sculptured ice phase and the red cells. When the concentration of HES is increased, the particulate phase becomes more prominent and at 14% HES appears to surround nearly all cells. In cells frozen in saline alone and 4% HES, the cytoplasm in a majority of cells has numerous cavities and depressions. Since such units haemolyse badly when thawed, it is possible that these regions indicate structural damage. In contrast, those units frozen with 14% HES (in which nearly 85% of the cells survive freeze-thaw) possess cells which only infrequently have such regions in the cytoplasm.

Blood Preservation↗
PubMed1978

Presence of an actin-like protein in mycelium of Neurospora crassa.

Addition of ATP, CaCl2, and KCl to supernatants prepared from mycelia of Snowflake (strain 507), a morphological mutant of Neurospora crassa, results in the formation of filaments 70 nm in diameter. The "decorated" appearance of these filaments after incubation with heavy meromyosin from rabbits suggests they are actin-like.

Actins↗