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Biomedical subjects

A Waxman

Publications and source records attributed to A Waxman.

At least 19 recordsLinked to original sources
PubMed2005

Ecteinascidin-743 (ET-743) for chemotherapy-naive patients with advanced soft tissue sarcomas: multicenter phase II and pharmacokinetic study.

PURPOSE: To evaluate the response rate, toxicity profile, and pharmacokinetics of ecteinascidin-743 (ET-743) as first-line therapy in patients with unresectable advanced soft tissue sarcoma (STS). PATIENTS AND METHODS: Thirty-six patients with STS were enrolled onto the study between September 1999 and August 2000. Patients were treated with 1.5 mg/m2 of ET-743 given as a 24-hour continuous intravenous (IV) infusion every 21 days. Pharmacokinetic sampling was performed in 23 patients. RESULTS: One complete and five partial responses were achieved in 35 assessable patients for an overall response rate of 17.1% (95% CI, 6.6% to 33.6%). In addition, one patient had a minor response, leading to an overall clinical benefit of 20%. Neutropenia and transaminitis were the main grade 3 to 4 toxicities, which occurred in 33% and 36% of the patients. The estimated 1-year progression-free and overall survival rates were 21% (95% CI, 11% to 41%) and 72% (95% CI, 59% to 88%), respectively. Total body clearance (L/h) was not significantly correlated with body-surface area (r = -0.28; P = .21). Mild hepatic impairment or the extent of prior cytotoxic therapy does not seem to contribute significantly to the high interpatient variability (49%) in the clearance of this drug. Severity of treatment-related toxicity was not correlated with pharmacokinetic variables. CONCLUSION: ET-743 demonstrates clinical activity as first-line therapy against STS with acceptable toxicity. Additional studies to establish empirical dosing guidelines may be necessary to improve the safety of the drug in patients with varying degrees of hepatic dysfunction and definitively establish the role of ET-743 for patients with these malignancies.

Adult↗
PubMed2005

Aortic root infection in a prosthetic valve demonstrated by gallium-67 citrate SPECT.

A 70-year-old man presented with 6 weeks of worsening low back pain, fever, sweating, and weight loss with known severe lumbosacral osteoarthritis. His history included CABG in 1992, porcine aortic valve replacement, and permanent pacemaker implantation in 2002. CT of the chest, abdomen, and pelvis did not demonstrate a cause for the symptoms. Blood cultures grew penicillin-sensitive enterococcus and he was referred for evaluation of possible osteodiskitis or epidural abscess. Gallium planar imaging demonstrated increased activity in the lumbar spine, suspicious for the presence of infection, and activity was noted in the mid mediastinum as well. SPECT clearly showed increased Ga-67 activity in the region of the aortic root, suspicious for infection. A perivalvular aortic root abscess was subsequently demonstrated by transesophageal echo. This case illustrates the value of Ga-67 chest SPECT in patients with prosthetic valves for detection of endocarditis.

Aged↗
PubMed2001

Public-private health partnerships: a strategy for WHO.

Following early success with a number of high-profile partnerships, WHO is increasingly working with the private for-profit sector. In so doing, the organization finds itself in the maelstrom of a vibrant debate on the roles of public, civic, and commercial entities in society and on the appropriate modes of interaction among them. This paper examines WHO's involvement with the commercial sector, particularly in partnerships. WHO's approach to this sector is outlined and the criticisms levelled at public-private partnerships are reviewed. An indication is given of the steps recently taken by WHO to confront the concerns that have been expressed. The paper argues that partnership between WHO and the commercial sector is inevitable and that it presents considerable opportunities, but also significant risks, for the organization and for public health. A strategy is proposed for directing the debate on issues critical to WHO and its role in the promotion and protection of public health.

Communicable Diseases↗
PubMed2000

What do adolescent females know about breast cancer and prevention?

Background: Many lifelong habits begin during adolescence. These habits can have profound, long-term ramifications on health. An important health habit is self-breast examination (SBE). The purpose of this study is to assess adolescent females' knowledge of breast cancer and breast cancer prevention. A survey was developed with questions that focused on female adolescents' knowledge of these topics. This information will assist health professionals in educating teens and forming public policy.Methods: Anonymous surveys consisting of ten questions were distributed to 280 females aged 13-17. These questions pertained to breast cancer with an emphasis on SBE, mammography, and risk factors. Questions were analyzed by chi square calculations. An additional section of the survey contained demographic characteristics of the respondents. Parental consent was obtained prior to completion of the surveys in accordance with the Institutional Review Board at St. Luke's Hospital. Surveys were administered during health class in a local high school.Results: One hundred and fifteen surveys were returned. Ages of participants were 13 to 17. The ethnic background of all participants were similar in that the majority were Caucasian. The overall percentage of correct answers was 65%. The majority of students knew what a mammogram is (92%) and how often screening should occur (65%), however, only 25% knew at what age screening should begin. It was encouraging that 80% of the students knew how often to perform SBE although only about half (53%) knew the time of the month this should be done. It was also encouraging that 83% knew that breast cancer is the second leading cause of cancer death, but the knowledge regarding risk factors that could possibly affect them was poor (36%). A statistically significant findings was that in the twenty percent of the students who had been taught SBE, 10 (43.5%) actually perform them. This is in relation to 2.2% of students who perform exams without any prior instruction. There was no statistically significant difference in the final score between students who had been taught how to perform exams and students who had not.Conclusions: Developing sound health habits as an adolescent should transcend to good health maintenance practices as an adult. Our study showed that adolescent females significantly lack knowledge relating to breast cancer. Adolescent females need to be better educated on the basic facts, including risk factors, screening procedures and SBE. With the incidence of breast cancer so high, knowledge of breast cancer and its prevention may result in earlier diagnosis and subsequently better long term outcomes.

Journal Article↗
PubMed1999

Fat intolerance depends on rapid gastric emptying.

Patients with fat intolerance complain of early satiety, bloating, nausea, and vomiting. Since these symptoms are similar to those of patients with postgastrectomy dumping syndrome, we hypothesized that fat intolerance may be associated with early, rapid gastric emptying. Using a three-meal gastric emptying study, we compared gastric emptying in nine patients with a history of fat intolerance and nine normal volunteers. On three separate days, 500-ml radiolabeled test meals containing 0, 15, or 60 g of fat were studied. The percentages of the test meal emptied at 15 and 60 min were analyzed by repeated measures two-way ANOVA. At 15 min (p < 0.05) but not 60 min, gastric emptying was faster in patients than normals. Gastric emptying at 15 min (p < 0.001) and 60 min (p < 0.001) depended on the dose of fat. We conclude that fat intolerance is associated with early, rapid gastric emptying.

Adult↗
PubMed1993

Serial thallium-201 scintigraphy in osteosarcoma. Correlation with tumor necrosis after preoperative chemotherapy.

In 27 patients with extremity lesions (24 osteosarcoma, three malignant fibrous histiocytoma), a notable decrease in thallium-201 uptake was correlated with a good response to preoperative chemotherapy of the primary tumor. A good response is indicated by a greater than 95% tumor necrosis. Serial quantitative thallium-201 uptake of malignant bone tumors in patients receiving preoperative chemotherapy therefore can accurately predict a good histologic response and prognosis. Serial thallium scintigraphy can furthermore identify poor responses within two weeks after the initiation of treatment, or can prompt an early change in preoperative chemotherapy and facilitate limb salvage surgery.

Adolescent↗
PubMed1991

Thallium-201 scintigraphy in differentiated thyroid cancer: comparison with radioiodine scintigraphy and serum thyroglobulin determinations.

The role of thallium-201 (201TI) scintigraphy in the follow-up evaluation of differentiated thyroid carcinoma (DTC) is controversial. Desirable characteristics of 201TI scintigraphy including the potential for no thyroid hormone withdrawal, immediate imaging postinjection, and low radiation burden relative to iodine-131 (131I) suggests it is logistically superior to 131I scintigraphy. Fifty-two patients with DTC were evaluated with 201TI and 131I neck and chest images, and serum thyroglobulin measurements. In post-thyroidectomy and pre-131I ablation therapy patients, very little 201TI accumulation was noted within the thyroid bed, with discordantly increased 131I activity and normal serum thyroglobulin measurements. Twenty-nine percent of patients evaluated after 131I ablative therapy had elevated serum thyroglobulin levels and localized neck and chest abnormalities on 201TI scan that were not seen on 131I studies. Our data suggest that 201TI is more sensitive than 131I diagnostic (5 mCi) studies for detection of DTC, while 131I is more sensitive in detecting normal residual thyroid tissue postoperatively.

Adenocarcinoma↗
PubMed1990

Thallium-201 scintigraphy in bone sarcoma: comparison with gallium-67 and technetium-MDP in the evaluation of chemotherapeutic response.

This study attempts to characterize thallium-201 (201TI) uptake in patients with bone and soft-tissue sarcoma and to compare these findings with gallium-67 (67Ga) and bone scintigraphy with emphasis on evaluating tumor viability before and after chemotherapy. Thirty-eight patients with surgically-proven sarcomas were evaluated. All patients had gallium and thallium studies. Nineteen patients underwent pre- and post-chemotherapy thallium and evaluation. Seven patients also had technetium-99m-MDP (99mTc-MDP) bone scintigraphy comparisons. Pathologic changes pre- and postchemotherapy were graded on the basis of %tumor necrosis as defined histologically. Scintigraphic comparisons demonstrated a high degree of correlation with 201TI and poor correlation with 99mTc-MDP. Thallium-201 was superior to 99mTc-MDP and 67Ga in predicting tumor response to chemotherapy as determined by %tumor necrosis determined histologically. Gallium was superior to Tc-MDP in predicting response to chemotherapy. However, both 67Ga and 99mTc-MDP appear to be affected by factors other than tumor activity.

Adolescent↗
PubMed1989

Responses of left and right ventricular ejection fractions to aerobic and anaerobic phases of upright and supine exercise in normal subjects.

The effects of aerobic and anaerobic exercise on ventricular performance were studied in 13 normal subjects who underwent simultaneous pulmonary gas exchange evaluation and exercise radionuclide ventriculography in the supine and upright postures. Right and left ventricular ejection fraction was measured serially at 2-minute intervals during exercise. The anaerobic threshold occurred at 74% and 80% of maximum heart rate, respectively, during upright and supine exercise. Left and right ventricular ejection fractions rose from rest to the anaerobic threshold (p less than 0.01, p less than 0.01, respectively) and there was a further increase between the anaerobic threshold and maximum exercise (p less than 0.01, p less than 0.01, respectively). The rate of rise of ejection fraction beyond the anaerobic threshold was slightly blunted compared with the rise prior to attaining the anaerobic threshold. There was no significant difference in ventricular performance between supine and upright exercise. The data demonstrate that ventricular performance increases steadily during exercise and is not limited by the conversion of aerobic to anaerobic metabolism.

Adult↗
PubMed1989

"Upward creep" of the heart: a frequent source of false-positive reversible defects during thallium-201 stress-redistribution SPECT.

A new cause of artifactual 201Tl defects on single photon emission computed tomography (SPECT) termed "upward creep" of the heart is described. In 102 consecutive patients undergoing 201Tl SPECT, 30 (29%) demonstrated upward creep defined by an upward movement of the heart of greater than or equal to 2 pixels during acquisition. In 45 consecutive patients with a less than 5% likelihood of coronary artery disease, 17 (38%) had upward creep. Of these nine had reversible 201Tl defects localized to the inferior and basal inferoseptal walls, while none of the 28 without upward creep had defects. The 17 low likelihood patients with upward creep had longer exercise duration and higher peak heart rate than those without upward creep. In five additional low likelihood patients with upward creep in whom imaging was immediately repeated, the upward creep pattern disappeared on the repeated images. After we changed our test protocol to begin imaging 15 min postexercise, only five (14%) of 36 low likelihood patients tested demonstrated upward creep. Upward creep is probably related to a transient increase in mean total lung volume early following exhaustive exercise, resulting in a mean lower position of the diaphragm (and thus the heart) at the beginning of imaging. The frequency of this source of false-positive 201Tl studies can be reduced by delaying SPECT acquisition until 15 min postexercise.

Adult↗
PubMed1988

The distribution of microtubule-associated protein 2 changes when dendritic growth is induced in rat sympathetic neurons in vitro.

We have examined the distribution of microtubule-associated protein 2 in embryonic rat sympathetic neurons grown under culture conditions that alter morphological development. Cultures were established in serum-free medium. After 8 days some were transferred to a serum-containing medium, which promotes dendritic development. Sister cultures were maintained in serum-free medium, which inhibits dendritic growth but permits normal axonal development. After growth for 2-6 weeks in serum-containing medium, sympathetic neurons were multipolar, with short, tapering dendrites and long, thin axons. Intense immunoreactivity for microtubule-associated protein 2 was observed in the somata and dendrites of all neurons, but there was little or no staining of the network of axonal processes that ran between cell somata. When the morphology of individual cells was assessed by injection of fluorescent dye before immunostaining, we found that staining for microtubule-associated protein 2 extended to the distal tips of the dendrites while the axon was essentially unstained, even in its proximal portion. Neurons from sister cultures that were not exposed to serum were usually unipolar, having only an axon. Under these conditions microtubule-associated protein 2 was also expressed, but its distribution was altered: intense immunostaining for microtubule-associated protein 2 was present in axons as well as somata. Staining in axons could sometimes be traced for several millimeters, but, since unstained segments of axons were also common, microtubule-associated protein 2 probably was not present throughout the entire axonal arborization. These results show that the expression of microtubule-associated protein 2 is not of itself sufficient to induce the formation of dendrites. Despite the association of microtubule-associated protein 2 with the axonal cytoskeleton, the light microscopic morphology of the axons was not obviously altered.

Animals↗
PubMed1988

Patient motion in thallium-201 myocardial SPECT imaging. An easily identified frequent source of artifactual defect.

Because Tl-201 SPECT requires that patients remain in an awkward position for a prolonged time, patient motion is a potentially serious source of artifactual defects on tomographic reconstructions. Thus, a simple method was developed for detection and correction of motion from SPECT images using a Co-57 point source placed on the lower anterior chest, an area remaining in the camera's field of view throughout imaging. In the absence of motion, this point source inscribes a straight line on planar summation of the 32 projections over 180 degrees. Movement is detected by deviation from this line. The number of pixels of motion is used to shift images so that the resultant images of the point source are linear. The method of motion detection and correction was tested in 48 consecutive patients undergoing Tl-201 SPECT. The corrected and uncorrected images were reconstructed and long and short axis tomographic cuts were quantitatively analyzed using circumferential profiles of maximal counts with comparison to the lower limits of normal. Motion was detected in eight of 48 patients (17%). The amount of motion was 2 pixels in three patients and 1 pixel in five patients. Quantitative defect extent was less after correction in seven of eight patients, with a mean decrease of 71% in patients with 2 pixel motion and 44% in patients with 1 pixel motion. This corresponded with a definite reduction in the size of the tomographic defect by visual analysis, and closer resemblance to quantitatively analyzed planar images performed either before or after tomography in the same patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Transient ischemic dilation of the left ventricle on stress thallium-201 scintigraphy: a marker of severe and extensive coronary artery disease.

On exercise thallium-201 scintigraphy, it has been noted that the size of the left ventricle is sometimes larger on the immediate poststress image than on the 4 hour redistribution image; this phenomenon has been termed transient ischemic dilation of the left ventricle. The angiographic correlates of this finding were assessed in 89 consecutive patients who underwent both stress-redistribution thallium-201 scintigraphy and coronary arteriography. A transient dilation ratio was determined by dividing the computer-derived left ventricular area of the immediate postexercise anterior image by the area of the 4 hour redistribution image. In patients with a normal coronary arteriogram or nonsignificant coronary stenoses (less than 50%), the transient dilation ratio was 1.02 +/- 0.05 and, therefore, an abnormal transient dilation ratio was defined as greater than 1.12 (mean + 2SD). The transient dilation ratio was insignificantly elevated in patients with noncritical coronary artery disease (50 to 89% stenosis) (1.05 +/- 0.05) and in patients with critical stenosis (greater than or equal to 90%) of only one coronary artery (1.05 +/- 0.05). In contrast, in patients with critical stenoses in two or three vessels, the transient dilation ratio was significantly elevated (1.12 +/- 0.08 and 1.17 +/- 0.09, respectively; p less than 0.05 compared with all other patient groups). An abnormal transient dilation ratio had a sensitivity of 60% and a specificity of 95% for identifying patients with multivessel critical stenosis and was more specific (p less than 0.05) than were other known markers of severe and extensive coronary artery disease, such as the presence of multiple perfusion defects or washout abnormalities, or both.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Changes in distribution of lung perfusion and ventilation at rest and during maximal exercise.

A new method for evaluation of changes in the distribution of pulmonary perfusion and ventilation during exercise was applied to normal male volunteers. Ventilation and perfusion scans were done with the subjects seated on a bicycle ergometer. The resting studies utilized krypton 81 (81mKr) for ventilation and technetium 99m (99mTc) macroaggregate albumin intravenously for perfusion. Exercise studies were done when 80 percent of maximum predicted heart rate was maintained for five minutes and utilized 81mKr for ventilation and a tenfold dose of 99mTc for perfusion. Higher dose of 99mTc would minimize the effect of radioactivity left over from the resting study. This method allowed us to assess changes in ventilation and perfusion in normal subjects induced by exercise, but may also be applicable in a variety of cardiopulmonary conditions that affect pulmonary ventilation and perfusion or both.

Adult↗
PubMed1985

Quantification of rotational thallium-201 myocardial tomography.

A comprehensive method is described for quantification of the relative 3-dimensional distribution of Tl-201 in the myocardium, following stress and subsequent washout. The method uses maximal-count circumferential profiles of well-defined long- and short-axis tomograms to determine the 3-dimensional distribution of Tl-201; it then maps this distribution onto a 2-dimensional polar representation. Abnormal thallium distribution or washout is identified by automatic computer comparison of each patient's profile with the corresponding lower limits of normal profiles. Abnormality is expressed as a percentage of the entire myocardium by use of polar maps for extent and severity. The binary extent map expresses the degree of abnormality. Preliminary criteria for abnormality were derived from the tomographic results of 25 normals and 28 patients with documented coronary artery disease. The results were normal in 23 of the 25 normals and were abnormal in 25 of the 28 CAD patients. In addition, the computer output correctly localized the presence or absence of disease in 46 of 56 coronary circulations.

Adult↗
PubMed1984

Sialadenitis following I-131 therapy for thyroid carcinoma: concise communication.

During a 4-yr period, ten of 87 patients (11.5%) who received therapeutic doses of radioactive iodine (I-131) for thyroid carcinoma developed acute and/or chronic sialadenitis involving the parotid (five patients) or submandibular (four patients) glands, or both (one patient). Nine of the 10 patients had received prior I-131 therapy; the precipitating I-131 dose varied between 10 and 164 mCi. Onset of symptoms occurred between 1 day and 6 mo following therapy and the duration varied from 3 wk to 21/2 yr. This complication occurs more often than has been appreciated.

Adenocarcinoma↗