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Biomedical subjects

D Miller

Publications and source records attributed to D Miller.

At least 901 records · Page 50Linked to original sources
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Nasopharyngeal carcinoma: the Dana-Farber Cancer Institute experience with 24 patients treated with induction chemotherapy and radiotherapy.

Nasopharyngeal carcinoma traditionally has been treated with radiotherapy alone. Although the probability of cure for patients with stage I and II nasopharyngeal carcinoma is high, the probability of cure for patients with stage III and IV disease is poor because of a higher rate of local-regional and distant failure. Between February 1981 and August 1986, 24 patients with previously untreated, stage IV nasopharyngeal carcinoma were treated with two to four monthly courses of cisplatin-based combination chemotherapy prior to radiotherapy. A response to induction chemotherapy was recorded in 75% of patients (29% complete response and 46% partial) prior to radiotherapy. By actuarial estimate with a median follow-up of 42 months, the 2-year failure-free survival for all patients was 57%. In conclusion, induction chemotherapy has significant activity in nasopharyngeal carcinoma. The toxicity of this approach, as well as the influence of initial histopathology and response to chemotherapy on survival, will be discussed.

Adolescent↗
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Medial collateral ligament knee sprains in college football. Brace wear preferences and injury risk.

In this prospective, multiinstitutional analysis of medial collateral ligament sprains in college football players, we categorized 987 previously uninjured study subjects according to frequency of wearing preventive knee braces, studied the patterns by which 47 of 100 injuries occurred to unbraced knees, and identified several extrinsic, sport-specific risk factors shared for both braced and unbraced knees. The attendance, brace wear choice, position, string, and session of each participant were recorded daily; medial collateral ligament sprains were reported whenever tissue damage was confirmed. Both the likelihood of wearing braces and risk of injury without them was highly dependent on session (games/practices), position group (line, linebacker/tight end, skill), and string group (players/nonplayers). Subjects wearing braces often faced a high injury risk to their unbraced knees, a finding compatible with the opinion that braces were a necessary evil, best worn when concern over danger of injury outweighed desire for speed and agility. It is concluded that to avoid misinterpretations due to the confounding influence of brace wear selection bias, accurate investigation of daily brace wear patterns is required. Then, before considing the impact of preventive knee braces, a repartitioning of the data base is essential to assure that only similar groups will be compared.

Athletic Injuries↗
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Medial collateral ligament knee sprains in college football. Effectiveness of preventive braces.

This is the second of 2 articles on a 3-year investigation of medial collateral ligament sprains of the knee to assess the effectiveness of prophylactic knee braces in NCAA Division I college football players. Position, string, type of session, and daily brace wear were recorded. The injury rates for braced and unbraced knees were used to create an incidence density ratio. The data were stratified and simultaneously controlled for position, string, and session and evaluated for their statistical significance. The 987 Big Ten players generated 155,772 knee exposures over the study period (50% braced). Noticeable differences existed in the rates of injury for the braced and unbraced knees in almost every position during practices, depending on player or nonplayer status. When the influential factors of position, string, and session are considered, there is a consistent but not statistically significant tendency for the players wearing preventive knee braces to experience a lower injury rate than for their unbraced counterparts. For starters and substitutes in the line positions, as well as the linebackers and tight ends, there was a consistent trend toward a lower injury rate in both practices and games. The braced players in the skill positions (backs/kickers), at least during games, exhibited a higher injury rate.

Athletic Injuries↗
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Ingluvial squamous cell carcinoma in a game chicken.

A 4.5-yr-old rooster was presented for a "lump on the neck." The bird exhibited dyspnea immediately prior to death. Necropsy revealed a crateriform lesion in the crop. Histologically, the lesion was diagnosed as an invasive squamous cell carcinoma, extending almost the entire thickness of the crop. Polymerase chain reaction and ultrastructural examination failed to identify a viral component. Early vascular invasion was identified.

Animals↗
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Retinopathy of prematurity in discordant twins.

Discordant twins may be at increased risk for retinopathy of prematurity (ROP) because of factors related to their unequal growth. Discordancy is defined as a difference of 15% or more in the birth weights of the two infants. We examined the data in 26 sets of discordant twins from six NICUs, including birthweight, gestational age, sex, and highest grade of ROP. Thirty-eight percent (10) of the lower birthweight infants had higher grades of ROP than their twin. Twenty-three percent (6) of the heavier birthweight twins had higher grades of ROP than their smaller siblings. Three infants reached threshold, and five were prethreshold. In every case, their twin siblings had mild or no ROP. Thirty-eight percent of the twins (10) had the same ROP outcome.

Birth Weight↗
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Calibration of trephine blade depth.

PURPOSE: To assess the accuracy and precision of the Barron radial vacuum trephine as an instrument for corneal lamellar dissection. METHODS: We describe a practical method to calibrate individual trephines prior to lamellar corneal procedures using the calibration microscope designed for diamond knives. RESULTS: We observed that one turn (360 degrees) of the trephine produced a mean blade displacement of 0.25 mm. However, individual trephines demonstrated a significant range of variability. CONCLUSION: For highly accurate trephination, it is useful to calibrate each individual trephine using the calibration microscope.

Calibration↗
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Factors affecting corneal strip stroma-to-stroma adhesion.

BACKGROUND: Successful laser in situ keratomileusis depends on strong adhesion between the dissected anterior corneal flap and the underlying stromal bed, without suturing. This study attempts to generate new information about the mechanism of this adhesion. METHODS: Strips of fresh bovine corneal stroma were dissected and split apart. The split strips were then made to adhere to each other with varying amounts of combined heat and drying. A relationship was developed between heat applied and hydration of strips. After each heat and drying treatment, the strips were pulled apart and the force needed to accomplish this task was measured. RESULTS: There was a tight linear correlation between increase in temperature and decrease in water content (R2 = 0.7414) and between decrease in water content and increase in the adhesive force (R2 = 0.3355). CONCLUSION: This model suggests that drying increases stromal-stromal adhesion. We speculate this is due to the increased concentration of surface molecules, which have high ionic charge densities and ionic bonding. A higher concentration of these molecules produces stroma-to-stroma adhesion via ionic bonding.

Adhesiveness↗
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Evaluation of increased aqueous outflow after radial keratotomy in enucleated bovine eyes.

PURPOSE: We studied the efficacy of using radial keratotomy incisions as a surgical method of increasing outflow facility in enucleated bovine eyes. METHODS: Each freshly enucleated bovine eye (n = 23) was cannulated to a system measuring the rate of flow into the eyes. Preoperatively, corneal thickness measurements were determined for all treated eyes. Radial keratotomy was performed in 13 eyes and a control set of eyes (n = 10) had no surgical manipulation. The intraocular pressure was set at 16.9 mm Hg. A clear zone of 10 mm was used for each eye with the incision depth set at 100% of the pachymetric reading. One set of experimental eyes had incisions that remained in the clear cornea, and the other set had incisions that reached 2 mm beyond the limbus into sclera. Preoperative outflow measurements were performed on each eye. Postoperative measurements were made after 10 incisions and 20 incisions. All eyes were checked for perforation after surgery and discarded if a perforation was found. RESULTS: No eye included in the analysis was perforated. The preoperative (baseline) total flow rate was 27.90 +/- 3.72 mu 1/min at 16.9 mmHg. The flow rate increased by 23.5% (over baseline) with 20 radial keratotomy incisions. A paired t-test was used to statistically compare the outflow measurements before radial keratotomy and after the first and second set of radial incisions. The increases in flow were found to be statistically significant (P < .005) for both 10 and 20 radial incisions. CONCLUSION: Assuming the flow measurements (flow rate) in these experiments parallel outflow facility, radial keratotomy increases the outflow facility in enucleated bovine eyes.

Animals↗
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Cave art: an early example of information processing.

This article suggests that ancient cave paintings are evidence of new important brain functions, or "evolutionary software," that facilitated the conceptual and motor processes needed to create a visual scene and render it graphically.

Animals↗
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Endogenous Pseudallescheria boydii endophthalmitis in a patient with ring-enhancing brain lesions.

A 46-year-old man, status post liver transplantation and taking immunosuppressive medications, was admitted after suffering a generalized seizure. Magnetic resonance imaging of the brain revealed two ring-enhancing lesions and treatment was begun for presumed toxoplasmic encephalitis. He was already receiving amphotericin B for a skin lesion suspected to be caused by candidiasis. One day after the seizure, he complained of photophobia in the left eye. Intraocular inflammation and a small infiltrate in the macula were seen. Vision deteriorated over the next three days. Vitreous tap and injection of amphotericin B and vancomycin were performed, but the intraocular inflammation continued to increase. On day 15, a vitrectomy was performed. The vitreous specimen ultimately grew Pseudallescheria boydii. The patient died on hospital day 30 from complications of the brain abscesses. Pseudallescheria boydii should be considered in the differential diagnosis of endophthalmitis, especially in patients with immunosuppression, serious medical disease, or ring-enhancing brain lesions.

Brain↗
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Effects of dialysis factors and route of administration on response of hemodialysis patients to recombinant human erythropoietin.

Data on the use of recombinant human erythropoietin (rHuEPO) were obtained from 25 hemodialysis centers to determine whether route of administration (intravenous [i.v.] vs. subcutaneous [s.c.]) or various dialysis factors influenced the response to rHuEPO; 844 of 958 patients had sufficient data for evaluation. Hematocrit (HCT) increased from 23.8 to 29.1% after a mean rHuEPO treatment period of 202 days; 48.4% of all patients did not reach a HCT greater than or equal to 29%. The s.c. route increased HCT more than the i.v. route. Multivariate analysis of the response (i.e., increase in HCT from baseline) showed a positive correlation with more rapid dialysis but a negative correlation with reuse, baseline HCT, transfusion dependence, and frequency of administration. The effects of dialysis and reuse were not present when the response was normalized by weekly dose. It was concluded that one half of all patients treated did not attain the recommended target HCT, perhaps due to economic constraints or resetting of goals. The s.c. route may be preferable to optimize response.

Drug Administration Schedule↗