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Biomedical subjects

M Phillips

Publications and source records attributed to M Phillips.

At least 109 records · Page 6Linked to original sources
PubMed1994

Boron neutron capture therapy: a mechanism for achieving a concomitant tumor boost in fast neutron radiotherapy.

PURPOSE: For many years neutron radiation has been used to treat malignant disease both as fast neutron radiotherapy and as thermal neutron induced boron neutron capture therapy (BNCT). To date, these two approaches have been used independently of one another due to the large difference in neutron energies each employs. In this paper we discuss the potential application of BNCT to enhance the therapeutic effectiveness of a fast neutron radiotherapy beam. METHODS AND MATERIALS: Measurements are presented for the thermal neutron component that is spontaneously developed as the University of Washington fast neutron radiotherapy beam penetrates a water phantom. The biological effect of this thermalized component on cells "tagged" with boron-10 (10B) is modeled mathematically and the expected change in cell survival calculated. The model is then extended to estimate the effect this enhanced cell killing would have for increased tumor control. RESULTS: The basic predictions of the model on changes in cell survival are verified with in vitro measurements using the V-79 cell line. An additional factor of 10-100 in tumor cell killing appears achievable with currently available 10B carriers using our present neutron beam. A Poisson model is then used to estimate the change in tumor control this enhanced cell killing would produce in various clinical situations and the effect is sufficiently large so as to be clinically relevant. It is also demonstrated that the magnitude of the thermalized component can be increased by a factor of 2-3 with relatively simple changes in the beam generating conditions. CONCLUSION: BNCT may provide a means of enhancing the therapeutic effectiveness of fast neutron radiotherapy in a wide variety of clinical situations and is an area of research that should be aggressively pursued.

Boron Neutron Capture Therapy↗
PubMed1994

Serum lipid levels in growth hormone-deficient men.

To evaluate the impact of growth hormone deficiency (GHD) on lipid metabolism, serum lipid and apolipoprotein concentrations were measured in 64 GHD adult males (mean age, 27.1 +/- 4.7 years). Results were compared with those obtained from an age- and sex-matched control group. Total cholesterol, low-density lipoprotein (LDL) cholesterol, and apolipoprotein (apo) B levels were significantly higher in GHD patients (P < .001). In 14 patients (23%), total cholesterol concentration exceeded the 95th percentile for healthy adults. Total and LDL cholesterol were inversely related to plasma insulin-like growth factor-I (IGF-I). Apo B also tended to be negatively correlated with IGF-I; however, statistical significance was not reached (P = .054). High-density lipoprotein (HDL) cholesterol and plasma triglyceride concentrations were within normal limits, whereas apo A-1 and A-2 levels were only slightly different from normal. We conclude that GHD in adulthood is associated with mild hypercholesterolemia due to an increased LDL cholesterol level. An inverse relationship was established between LDL cholesterol concentration and GH secretory status.

Adolescent↗
PubMed1994

Clinical paths for cardiac surgery patients: a multidisciplinary approach to quality improvement outcomes.

Implementation of clinical paths has resulted in a successful multidisciplinary approach for monitoring quality improvement outcomes in a select group of cardiovascular patients. This article defines clinical paths and explains their development, implementation, and evaluation. It also discusses how variances (which are defined as discrepancies between expected and actual events) were identified and how this information led to actions to improve patient outcomes. The roles of each health care professional are discussed in relation to clinical paths, and positive outcomes for the nurse, other health care professionals, and the institution are presented.

Clinical Protocols↗
PubMed1994

Grease gun injuries to the orbit and adnexa.

The grease gun injury is an uncommon injury to the orbit. However, high-pressure injection of grease, oil, or paint is frequently reported in injuries of the hand and usually affects the fingers or palm, which require complicated surgical and medical care. Two cases of grease gun injury to the orbit are reported: one, a catastrophic injury, and the other resulting in satisfactory recovery after surgical debridement and adjuvant medical treatment. Presentation, investigation, and therapy are discussed.

Accidents, Occupational↗
PubMed1994

Metabolic and environmental origins of volatile organic compounds in breath.

Although more than 200 volatile organic compounds (VOCs) have been identified in human alveolar breath, their origins are still mostly unknown. An attempt was made to determine whether the major VOCs in breath were derived from inside or outside the body--that is, were they products of metabolism or contaminants from the environment? The concentrations were measured of the 24 most abundant VOCs in the alveolar breath of 12 normal volunteers and also in the air they inspired. The polarity of the mean alveolar gradient (concentration in breath minus concentration in inspired air) was positive in 15 VOCs and negative in nine. The mean alveolar gradient varied from strongly positive (for example, 2,3,3-trimethylpentane), consistent with a metabolite manufactured in the body, to strongly negative (for example, isoprene), consistent with ingestion of an air pollutant which was then catabolised in vivo or excreted via an extra-pulmonary pathway.

Breath Tests↗
PubMed1994

Ryanodine and dihydropyridine binding patterns and ryanodine receptor mRNA levels in myopathic hamster heart.

We have determined the densities of sarcolemmal voltage-dependent Ca2+ channels (VDCC) and Ca(2+)-induced Ca2+ release channels (CICR) of sarcoplasmic reticulum (SR) in the cardiomyopathic hamster heart using [3H]PN-200 and [3H]ryanodine, respectively. Partially purified cardiac membrane preparations from myopathic animals exhibit a twofold higher capacity to bind both [3H]PN-200 and [3H]ryanodine. Crude particulate membrane fractions from normal and cardiomyopathic animals reveal no significant difference in receptor densities for [3H]PN-200, whereas densities for [3H]ryanodine binding sites and mRNA levels are significantly (P < 0.05) diminished in cardiomyopathic animals. Inhibition of [3H]ryanodine binding by either Ca2+ or Mg2+ (in mM) as well as temperature dependence for receptor activation for [3H]ryanodine (Q10) is not significantly different, whereas membranes isolated from cardiomyopathic hearts are 1.4-fold and threefold more sensitive to activation by doxorubicin and Ca2+ (in microM), respectively. Vesicles isolated from myopathic hearts are more sensitive to inhibition of Ca2+ uptake by doxorubicin. The higher densities of binding sites for [3H]PN-200 and [3H]ryanodine observed in partially purified membrane fractions from cardiomyopathic hearts are more likely the result of altered patterns with which T-tubule and CICR channels fractionate in preparations from cardiomyopathic hamster heart rather than transcriptional upregulation and may be a consequence of the deficiency in a dystrophin-associated glycoprotein recently identified. Downregulation and functional changes in CICR channels may alter SR Ca2+ transport and contribute to the progression of cardiomyopathy in the hamster.

Animals↗
PubMed1994

Phase II trial of docetaxel in patients with platinum-refractory advanced ovarian cancer.

PURPOSE: This phase II study was conducted to evaluate the efficacy and toxicity of docetaxel in the treatment of patients with platinum-refractory ovarian cancer. PATIENTS AND METHODS: Twenty-five patients with platinum-refractory advanced ovarian cancer were treated. Twenty of the patients had failed to respond to platinum-based front-line chemotherapy and five had failed to respond to platinum-based therapy repeated at relapse. One patient had received prior pelvic radiation therapy. Patients were required to have bidimensionally measurable disease. Docetaxel was administered at a dose of 100 mg/m2 intravenously (i.v.) over 1 hour every 21 days. Twenty patients received no corticosteroid premedication and five received premedication with corticosteroids and antihistamines. RESULTS: Eight of 23 assessable patients (35%) had a partial response (PR; 95% confidence interval, 16% to 57%). The median response duration was 5 months. Hospitalization for toxicity, predominantly neutropenic fever, occurred in 12 patients (48%) and 16% of courses. Anemia was common in the study population. Nonhematologic toxicities included alopecia, rash, fluid retention, diarrhea, peripheral neuropathy, and hypersensitivity reactions. CONCLUSION: Docetaxel demonstrates significant activity in patients with platinum-refractory advanced ovarian cancer. Routine premedication is recommended. Further investigations of this agent in ovarian cancer, including combinations with other active agents, appear indicated.

Adult↗
PubMed1994

Network commercials promote legal drugs: outnumber anti-drug PSA's 45-to-1.

During the week of September 16 to 22, 1990, commercials promoting drugs and alcohol outnumbered the networks' news stories, documentaries, and PSA's about illegal drugs by a ratio of almost 39-to-1. If you consider the PSA's alone, the commercials promoting drugs and alcohol outnumbered them by a ratio of almost 45-to-1.

Adolescent↗
PubMed1994

Enhancement of fast neutron beams with boron neutron capture therapy. A mechanism for achieving a selective, concomitant tumor boost.

Both fast neutron radiotherapy and boron neutron capture therapy (BNCT) have been utilized to treat malignant disease. Herein we discuss the potential of combining these treatments to enhance the effectiveness of fast neutron therapy through a concomitant BNCT boost. Using a fast neutron beam generated from a 50 MeV proton on beryllium reaction, we have determined that 0.1% of the beam per microgram of boron-10 per gram of tissue (microgram/g) can be deposited via BNCT. Our mathematical modeling predicts that BNCT enhancement of our beam will lead to an additional 1-2 logs of tumor cell kill for boron-10 concentrations of 30-50 micrograms/g. We have validated this via V-79 cell line in vitro measurements. A Poisson model estimation of how this additional cell kill will influence local tumor control, predicts that BNCT enhancement of fast neutron radiation will lead to a clinically significant improvement in outcome.

Animals↗
PubMed1994

Alveolar gradient of pentane in normal human breath.

Previous studies have raised the question of whether pentane is a normal constituent of human breath, since its concentrations in inspired room air and expired breath are often similar. Using a highly sensitive assay for volatile organic compounds, we studied 37 normal subjects in order to determine the alveolar gradient of pentane in their breath (i.e. concentration in alveolar breath minus concentration in the inspired air). The chemical identity of pentane was confirmed by mass spectroscopy. The alveolar gradient of pentane was zero +/- 0.175 nmol/l in 54.1% of subjects, and distributed in an approximately bell-shaped curve. Determination of the alveolar gradient divided the normal subjects into three groups: the "passive equilibrators" who did not appear to excrete pentane in the breath (the majority), "metabolizers" who actively catabolized inhaled pentane, and "manufacturers" who excreted more pentane than they inhaled.

Breath Tests↗
PubMed1994

[Diabetes in Mexico: what does the National Health Survey tell us?].

The purpose of this monograph is to describe the sociodemographic and health characteristics of individuals who identified themselves as diabetics (through self-notification) in a national health survey that was conducted in Mexico in 1988 and in which information about more than 200,000 persons was collected by interviewing an adult member of each household. Of the population surveyed, 1.2% stated being diabetic, and it was noted that the frequency of the disease increased with age and socioeconomic status and that it was 30% higher in women than in men. Diabetics had higher notification rates for hypertension, heart disease, and blindness than the rest of the population. Twenty percent of diabetic patients and 12% of nondiabetic individuals smoked. People with diabetes consulted physicians twice as often as nondiabetics and their chances of being hospitalized were four times higher. At the end we discuss the limitations and possible biases of self-notification as a method for detecting diabetics. Finally we conclude that diabetes is an important health problem in Mexico and that it warrants more attention from epidemiologists and other public health specialists.

Adolescent↗
PubMed1994

Opportunities for cost reduction in diabetic retinopathy treatment: case study from Mexico.

A study was performed in order to explore the costs of treating diabetic retinopathy at a large eye hospital in Mexico with a view to identifying opportunities for improving efficiency. Clinical records of a random sample of 69 diabetic patients were reviewed for data on each patient's background, medical history, and treatment; and the costs of all resources utilized in each type of procedure provided were documented and priced. The resulting data on clinical costs was complemented by data on the private costs of treatment (medical fees, accommodation costs, transportation costs, and lost wages) that were gathered from patient interviews. The study found that the patients, who were generally poor, shouldered a substantial economic burden associated with treatment at the hospital; however, less than half this burden was in the form of fees. The rest involved other out-of-pocket expenditures on food, travel, and accommodation (45% of the total) and lost wages (10% of the total). Suggestions for reducing various of these costs without endangering treatment quality are presented. These include suggestions for reducing waiting time; reducing the number of patient visits required by increasing the strength of individual laser treatments, completing more procedures in a single visit, and reviewing hospital policy on fluoroangiograms; and increasing the chances for early and effective treatment by educating at-risk relatives accompanying the patients about the need for early treatment.

Aged↗