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Biomedical subjects

D Miller

Publications and source records attributed to D Miller.

At least 595 records · Page 33Linked to original sources

Cellular X-ray repair parameters of early passage squamous cell carcinoma lines derived from patients with known responses to radiotherapy.

We have investigated X-ray survival parameters and repair of potentially lethal damage ( PLDR ) in ten early passage squamous cell carcinoma cell lines derived from patients who were biopsied before initiation of radiotherapy or after radiation therapy failure. Radiosensitivity (D0) ranged from 1.07 to 1.93 (Gy), extrapolation numbers (-n) from 1.17 to 2.14 and PLD recovery at 24 h from 1.4 to 20.3. Despite significant differences in these parameters amongst the cell lines, a firm correlation between radiocurability and any individual radiobiological parameter could not be established. Our data suggest that the mechanisms associated with radioresistance are complex and that any single radiobiological parameter may not predict clinical success or failure.

Carcinoma, Squamous Cell↗

Segmental hyperlucent defects in the liver.

When lucent defects in the liver have a segmental configuration, they may be on an ischemic basis and related to decreased vascular perfusion. Portal venous inflow, by virtue of its low pressure, is particularly susceptible to diversion by focal intrahepatic masses, intravenous thrombi, or external compression. Innovative operative techniques for tumor enucleation may also result in lucent defects that can be confused with, or conceal, pathology. A hypothesis relating such defects to diminished portal inflow and reduced glycogen content is proposed.

Female↗

Treatment of end-stage diabetic nephropathy: over a decade of experience at one institution.

Results of treatment of end-stage renal disease in 139 patients with diabetes mellitus revealed survival of 76% at 1 year and 48% at 5 years. These results compare favorably with other reports from Europe and the United States, probably because of the greater number of patients receiving renal transplants, and possibly because of the use of continuous ambulatory peritoneal dialysis as a recent treatment modality. Patients not receiving transplants were much older (mean age, 47.8 years) than those receiving transplants. Of those not given transplants, survival was best on CAPD. Comparison of those surviving at least 3 years was made with those expiring in the first year. Long-term survivors were younger, had diabetes for a shorter period, but had higher mean blood pressures and serum creatinine values than short-term survivors. Short-term survivors also had over a 50% incidence of prior myocardial infarction or cardiorespiratory arrest, while no long-term survivors had such a history. Long-term survivors were also more likely to have received a transplant, and short-term survivors were more likely to have received intermittent peritoneal dialysis or hemodialysis. A transplant from a living related donor is the treatment of choice for diabetics under age 40 and perhaps for older patients as well. The choice among CAPD, hemodialysis and cadaver transplant requires consideration of many factors.

Adult↗

Tubulin heterogeneity in the trypanosome Crithidia fasciculata.

The interphase cell of Crithidia fasciculata has three discrete tubulin populations: the subpellicular microtubules, the axonemal microtubules, and the nonpolymerized cytoplasmic pool protein. These three tubulin populations were independently and selectively purified, yielding, in each case, microtubule protein capable of self-assembly. All three preparations polymerized to form ribbons and sheets rather than the more usual microtubular structures. Analyses of the tubulin by two-dimensional polyacrylamide gel electrophoresis, isoelectric focusing, and peptide mapping indicated that the beta-tubulin complex remained constant regardless of source but that some heterogeneity was present in the alpha subunit. Cytoplasmic pool alpha tubulins (alpha 1/alpha 2) were the only alpha isotypes in the cytoplasm and also formed most of the alpha tubulin species in the pellicular fraction. Flagellar alpha tubulin (alpha 3) was the sole alpha isotype in the flagella; it appeared in small amounts in the pellicular fraction but was completely absent from the cytoplasm. In vitro translation products from polyadenylated RNA from C. fasciculata were also examined by two-dimensional polyacrylamide gel electrophoresis and possessed a protein corresponding to alpha 1/alpha 2 tubulin but lacked any alpha 3 tubulin. The alpha 3 polypeptide arose from a post-translational modification of a precursor polypeptide not identifiable by two-dimensional polyacrylamide gel electrophoresis as alpha 3. Peptide mapping data indicated that cytoplasmic alpha tubulin is the most likely precursor. These results demonstrate alpha-tubulin heterogeneity in this organism and also how close the relationship between flagellar and cytoskeletal tubulins can be among lower eucaryotes.

Animals↗

Incidence of hypothyroidism following multimodality treatment for advanced squamous cell cancer of the head and neck.

The incidence of chemical hypothyroidism, as manifested by elevated thyroid stimulating hormone (TSH) levels, has been estimated to be as high as 25% after radiation therapy and 45% after radiation therapy and surgery to the neck for treatment of nodal metastases from squamous carcinoma of the head and neck. We prospectively evaluated 43 previously untreated patients seen in the Dana Farber Cancer Institute Interdisciplinary Head and Neck Service who were treated with aggressive combination chemotherapy in addition to standard surgery and/or radiotherapy. All patients were serially monitored for serum TSH, serum T4, and clinical evidence of hypothyroidism. Following cis-platinum, bleomycin, and methotrexate chemotherapy and subsequent surgery and/or radiotherapy, decreased thyroid reserve appeared in 37% of patients at a median follow-up of 9 months. Thirty percent of patients receiving radiotherapy alone and 43% of patients receiving surgery and radiotherapy developed elevated TSH levels. Only one patient developed clinical symptoms. Other patients were asymptomatic despite persistently elevated TSH levels. Abnormalities appeared within the first 4 months after completion of all therapy and were slowly progressive. The addition of combination chemotherapy does not appear to increase the incidence or severity of thyroid dysfunction following radiation therapy and surgery to the neck. In view of the extended survival seen in patients treated with interdisciplinary regimens, we recommend that all patients receiving irradiation to the neck--particularly those patients having neck dissections or total laryngectomies--have routine thyroid function studies performed following the cessation of treatment.

Adolescent↗

Lamellar keratoplasty using a freezing platform.

We have used a freezing platform to prepare donor corneal material for lamellar grafting. Once frozen, the donor material assumes the consistency of balsa wood and can be easily curved and shaped to fit irregular recipient sites. A method for determining proper fit between donor and recipient is also presented.

Animals↗

Automated objective refractometers.

We have shown how the modern-day analysis of the aerial image produced by an indirect ophthalmoscope forms the basis for automated objective refraction. Objective automated optometers present with the advantages that they: record rapidly, thereby minimizing the effects of accommodative fluctuation and/or fixation instability, demand only low-level technical skill on the part of the operator, demand little of the patient beyond passive cooperation. Refractive findings obtained using objective automated refractors are counterparts of retinoscopic prescriptions and correlate about as well with subjective findings as do those obtained by the proficient retinoscopist.

Ophthalmoscopy↗

Glare measurement as a predictor of outdoor vision among cataract patients.

Eighty-four cataractous eyes of 52 consecutive patients and 81 normal eyes of 48 subjects were evaluated with a commercially availability glare tester. Tests results were compared to visual acuity determinations in the refracting lane for ability to predict vision outdoors under daylight conditions. Among cataract patients, predictability of the two methods of measurement was not significantly different when subjects faced away from the sun. Glare scores were significantly better predictors (nearly twice as predictive) of outdoor visual acuity among cataract subjects facing the sun. These results demonstrate that measurement of sensitivity to glare is an important clinical procedure for evaluating functional visual disability in cataract patients under glare-producing conditions.

Adult↗

Improved visualization through cataracts using intravitreal illumination.

It is known that intravitreal illumination during vitrectomy improves both contrast and resolution for the surgeon by eliminating backscatter and reflections from both cornea and lens. The experiments described in this paper set out to quantitate the amount of improvement in these optical parameters using simulated intravitreal illumination when a target was viewed behind a cataractous lens. The results show an almost fourfold increase in contrast and a twofold increase in resolution when the illumination is placed behind the cataract, ie, intravitreal illumination vs external microscope illumination where the illumination is placed between the cataract and the observer.

Animals↗

Simple method for locating the optical center of a lens.

This article evaluates an old and little used method, which involves holding a small light in front of the lens and marking the spot where the centers of the images reflected from the front and rear surfaces overlap. The location of the center found this way correlates very well with the marking lensometer method. This method may also be used while the patient is wearing the spectacle. Thus, the examiner may easily see the patient's pupillary center and the optical center simultaneously. Induced prismatic effects from inaccurate lens centering can easily be diagnosed without removing the spectacle from the patient's face.

Eyeglasses↗

AIDS in Europe.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗

Route of incorporation of alveolar palmitate and choline into surfactant phosphatidylcholine in rabbits.

Intratracheal injection of 3-day-old rabbits with radioactively labeled palmitic acid and choline results in an 8-10-fold increase in the efficiency of their incorporation into surfactant phosphatidylcholine when compared to the intravenous injection of these precursors. Based on labeling patterns in microsomal, lamellar body and alveolar wash fractions, the incorporation appears to be via normal surfactant synthetic pathways. Intratracheal injection of phospholipid precursors is useful for producing relatively high specific activity natural surfactant.

Animals↗