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Biomedical subjects

T Anderson

Publications and source records attributed to T Anderson.

At least 127 records · Page 7Linked to original sources
PubMed1996

High-dose chemotherapy supported by peripheral blood progenitor cells in poor prognosis metastatic breast cancer--phase I/II study. Edinburgh Breast Group.

Current treatments for metastatic breast cancer are not associated with significant survival benefits despite response rates of over 50%. High-dose therapy with autologous bone marrow transplantation (ABMT) has been investigated, particularly in North America, and prolonged survival in up to 25% of women has been reported, but with a significant treatment-related mortality. However, in patients with haematological malignancies undergoing autologous transplantation, haematopoietic reconstruction is significantly quicker and mortality lower than with ABMT, when peripheral blood progenitor cells (PBPCs) are used. In 32 women with metastatic breast cancer, we investigated the feasibility of PBPC mobilisation with high-dose cyclophosphamide and granulocyte colony-stimulating factor (G-CSF) after 12 weeks' infusional induction chemotherapy and the subsequent efficacy of the haematopoietic reconstitution after conditioning with melphalan and either etoposide or thiotepa. PBPC mobilisation was successful in 28/32 (88%) patients, and there was a rapid post-transplantation haematopoietic recovery: median time to neutrophils > 0.5 x 10(9) l-1 was 14 days and to platelets > 20 x 10(9) l-1 was 10 days. There was no procedure-related mortality, and the major morbidity was mucositis (WHO grade 3-4) in 18/32 patients (56%). In a patient group of which the majority had very poor prognostic features, the median survival from start of induction chemotherapy was 15 months. Thus, PBPC mobilisation and support of high-dose chemotherapy is feasible after infusional induction chemotherapy for patients with metastatic breast cancer, although the optimum drug combination has not yet been determined.

Adult↗
PubMed1996

Drugs in the aetiology of agranulocytosis and aplastic anaemia.

Agranulocytosis and aplastic anaemia are rare but serious conditions known to be caused by numerous drugs. Most of what is known or suspected about the aetiology is based on case reports, with only a few formal epidemiological studies that provide quantitative estimates of risk. Updated results have been obtained from a combined analysis of data from 3 case-control studies that used similar methods: the International Agranulocytosis and Aplastic Anemia Study (IAAAS), conducted in Israel and Europe; a study conducted in the northeast US; and a study conducted in Thailand. Totals of 362 cases of agranulocytosis, 454 cases of aplastic anaemia and 6458 controls were included in the analyses. The IAAAS and Thai study were population-based, providing estimates of the incidence of the 2 dyscrasias. The overall annual incidence of agranulocytosis in the ambulatory population was 3.4/10(6) in the IAAAS and 0.8/10(6) in Thailand; by contrast the incidence of aplastic anaemia was 2.0/10(6) in the IAAAS and 4.1/10(6) in Thailand. A total of 21 compounds were significantly associated with an increased risk of agranulocytosis in the IAAAS and US studies. Excess risks ranged from 0.06 to 13 cases/10(6) users/wk; the most strongly associated drugs were procainamide, anti-thyroid drugs and sulphasalazine. An association with drugs that had previously been suspected was also seen in Thailand. The overall aetiologic fractions of agranulocytosis due to drug use were 62% in the IAAAS, 72% in the US and 70% in Thailand. Eleven drugs were significantly associated with an increased risk of aplastic anaemia, with excess risks ranging from 1.4 to 60 cases/10(6) users in a 5-month period. The most strongly associated drugs were penicillamine, gold and carbamazepine. Aetiologic fractions were 27% in the IAAAS, 17% in the US and 2% in Thailand, which paralleled the prevalence of use of associated drugs in the 3 populations. The present results confirm that agranulocytosis is largely a drug-induced disease, with similar proportions accounted for in 3 disparate geographic regions. By contrast, although many of the expected associations were observed for aplastic anaemia, most of the aetiology is not explained by drugs. For all associated drugs, the excess risks are sufficiently low that blood dyscrasias should not figure prominently in the balancing of risks and benefits.

Agranulocytosis↗
PubMed1996

Incidence and non-drug aetiologies of aplastic anaemia in Thailand. The Thai Aplastic Anaemia Study Group.

A population-based, case-control study of aplastic anaemia has been conducted in Thailand since 1989. Up to December 1994, the overall annual incidence was 3.9/10(6) in Bangkok, 5.0/10(6) in Khonkaen and 3.0/10(6) in Songkla. In Bangkok, the incidence peaked in 2 age groups (at 15-24 yr and > or = 60 yr), whereas in Khonkaen and Songkla there was a consistent increase in incidence with increasing age. The results of case-control analyses for non-drug risk factors indicate a strong inverse association with socio-economic status present in all 3 areas; a strong association with grain farming in the 2 rural areas that does not appear to be explained by pesticides; an association with occupational exposure to solvents in Bangkok; and a positive association with hepatitis A seropositivity.

Adolescent↗
PubMed1996

Biomechanics and running economy.

Running economy, which has traditionally been measured as the oxygen cost of running at a given velocity, has been accepted as the physiological criterion for 'efficient' performance and has been identified as a critical element of overall distance running performance. There is an intuitive link between running mechanics and energy cost of running, but research to date has not established a clear mechanical profile of an economic runner. It appears that through training, individuals are able to integrate and accommodate their own unique combination of dimensions and mechanical characteristics so that they arrive at a running motion which is most economical for them. Information in the literature suggests that biomechanical factors are likely to contribute to better economy in any runner. A variety of anthropometric dimensions could influence biomechanical effectiveness. These include: average or slightly smaller than average height for men and slightly greater than average height for women; high ponderal index and ectomorphic or ectomesomorphic physique; low percentage body fat; leg morphology which distributes mass closer to the hip joint; narrow pelvis and smaller than average feet. Gait patterns, kinematics and the kinetics of running may also be related to running economy. These factors include: stride length which is freely chosen over considerable running time; low vertical oscillation of body centre of mass; more acute knee angle during swing; less range of motion but greater angular velocity of plantar flexion during toe-off; arm motion of smaller amplitude; low peak ground reaction forces; faster rotation of shoulders in the transverse plane; greater angular excursion of the hips and shoulders about the polar axis in the transverse plane; and effective exploitation of stored elastic energy. Other factors which may improve running economy are: lightweight but well-cushioned shoes; more comprehensive training history; and the running surface of intermediate compliance. At the developmental level, this information might be useful in identifying athletes with favourable characteristics for economical distance running. At higher levels of competition, it is likely that 'natural selection' tends to eliminate athletes who failed to either inherit or develop characteristics which favour economy.

Age Factors↗
PubMed1995

Medication use and the risk of Stevens-Johnson syndrome or toxic epidermal necrolysis.

BACKGROUND: Toxic epidermal necrolysis and Stevens-Johnson syndrome are rare, life-threatening, drug-induced cutaneous reactions. We conducted a case-control study to quantify the risks associated with the use of specific drugs. METHODS: Data were obtained through surveillance networks in France, Germany, Italy, and Portugal. Drug use before the onset of disease was compared in 245 people who were hospitalized because of toxic epidermal necrolysis or Stevens-Johnson syndrome and 1147 patients hospitalized for other reasons (controls). Crude relative risks were calculated and adjusted for confounding by multivariate methods when numbers were large enough. RESULTS: Among drugs usually used for short periods, the risks were increased for trimethoprim-sulfamethoxazole and other sulfonamide antibiotics (crude relative risk, 172; 95 percent confidence interval, 75 to 396), chlormezanone (crude relative risk, 62; 21 to 188), aminopenicillins (multivariate relative risk, 6.7; 2.5 to 18), quinolones (multivariate relative risk, 10; 2.6 to 38), and cephalosporins (multivariate relative risk, 14; 3.2 to 59). For acetaminophen, the multivariate relative risk was 0.6 (95 percent confidence interval, 0.2 to 1.3) in France but 9.3 (3.9 to 22) in the other countries. Among drugs usually used for months or years, the increased risk was confined largely to the first two months of treatment, when crude relative risks were as follows: carbamazepine, 90 (95 percent confidence interval, 19 to infinity); phenobarbital, 45 (19 to 108); phenytoin, 53 (11 to infinity); valproic acid, 25 (4.3 to infinity); oxicam nonsteroidal antiinflammatory drugs (NSAIDs), 72 (25 to 209); allopurinol, 52 (16 to 167); and corticosteroids, 54 (23 to 124). For many drugs, including thiazide diuretics and oral hypoglycemic agents, there was no significant increase in risk. CONCLUSIONS: The use of antibacterial sulfonamides, anticonvulsant agents, oxicam NSAIDs, allopurinol, chlormezanone, and corticosteroids is associated with large increases in the risk of Stevens-Johnson syndrome or toxic epidermal necrolysis. But for none of the drugs does the excess risk exceed five cases per million users per week.

Adrenal Cortex Hormones↗
PubMed1995

Flow cytometric measurement of proliferation-associated nuclear antigen P105 and DNA content in immuno-proliferative small intestinal disease (IPSID).

Immunoproliferative small intestinal disease (IPSID), most common in Mediterranean countries, is characterized by lymphomatous infiltration of the small intestine and is usually associated with the synthesis of anomalous immunoglobulin alpha heavy chains. Flow cytometric analysis of DNA content, S phase fraction, and quantitative analysis of the proliferation-associated nuclear antigen, P105, were performed in 23 patients with IPSID to determine if they could be used as prognostic indicators in this disease. Eighteen patients had low-grade, two had intermediate-grade, and three had high-grade lymphoma. Eight patients had clinical stage IE disease, 12 had stage IIE, and three had stage IIIE disease. Eleven patients survived > 5 yr (good prognosis), four survived between 2-5 yr (intermediate prognosis), and eight survived 2 yr or less (poor prognosis). The S phase fraction of patients with poor prognosis was significantly higher than those with intermediate or good prognosis (P < 0.004). Flow cytometric evaluation of S phase fraction may offer important prognostic information in patients with IPSID and could be useful in the clinical management of patients with this highly variable clinical syndrome. Further studies evaluating the value of DNA flow cytometry in larger groups of patients with IPSID are warranted.

Adult↗
PubMed1995

The effects of hyperoxia, mechanical ventilation, and dexamethasone on pulmonary antioxidant enzyme activity in the newborn piglet.

It has been previously shown that prophylactic, intravenous dexamethasone (DEX) and intratracheal recombinant human Cu/Zn superoxide dismutase (SOD) ameliorate lung injury in newborn piglets treated with 48 hr of hyperoxia and mechanical ventilation. DEX has many pharmacologic effects, including the possible induction of antioxidant enzyme systems. To investigate whether the effects of DEX are mediated by an increase in endogenous antioxidant enzyme activity, 5 groups of term newborn piglets were studied: Group 1 piglets were ventilated with room air for 48 hr; Group 2 animals were ventilated with 100% O2 for 48 hr; Group 3 animals were ventilated with room air for 48 hr and received DEX (0.7 mg/kg) every 12 h; Group 4 were ventilated with 100% O2 for 48 hr and also received DEX; Group 5 animals were no ventilated and were sacrificed at time 0. At the conclusion of the studies, bronchoalveolar lavage (BAL) was performed and the lungs were removed and homogenized. Lung tissue and BAL were analyzed for SOD, catalase, GPX activities, and total protein concentration. No significant differences in any of these assays were seen in either lung tissue or BAL in the 5 groups. These observations indicate that 48 hr of hyperoxia, mechanical ventilation, or dexamethasone treatment does not induce activity of SOD, catalase, or glutathione peroxidase (GPX) in the lungs of newborn piglets. Thus postnatal DEX appears to minimize neonatal lung injury by mechanisms that are independent of these enzymes.

Analysis of Variance↗
PubMed1995

Exercise echocardiography is an accurate and cost-efficient technique for detection of coronary artery disease in women.

OBJECTIVES: This study compared the accuracy and cost implications of using exercise echocardiography and exercise electrocardiography for detection of coronary artery disease in women. BACKGROUND: The specificity of exercise electrocardiography in women is lower than in men. Exercise echocardiography accurately identifies coronary artery disease in women, but its utility in place of exercise electrocardiography is unclear. METHODS: One hundred sixty-one women without a previous Q wave infarction underwent exercise echocardiography and coronary angiography. Positive findings were a new or worsening wall motion abnormality on the exercise echocardiogram and ST segment depression > 0.1 mV at 0.08 s after the J point on the exercise electrocardiogram (ECG). RESULTS: Coronary artery stenosis > 50% diameter narrowing was present in 59 patients; the sensitivity (mean +/- SD) of exercise echocardiography was 80 +/- 3%. In 48 patients with an interpretable ECG, the sensitivity of exercise echocardiography was 81 +/- 4%, and that of the exercise ECG was 77 +/- 3% (p = 0.50). In 102 patients without coronary artery disease, the overall specificity of exercise echocardiography was 81 +/- 4%. In 70 patients with an interpretable ECG, the specificity of exercise echocardiography (80 +/- 3%) exceeded that of the exercise ECG (56 +/- 4%, p < 0.0004). The accuracy of exercise echocardiography was also greater than exercise electrocardiography (81 +/- 5% vs. 64 +/- 6%, p < 0.005). Exercise echocardiography stratified significantly more patients of intermediate (20% to 80%) pretest disease probability into the high (> 80%) or low (< 20%) posttest probability group. In women without a previous exercise ECG, the specificity of exercise echocardiography continued to exceed that of exercise electrocardiography (80 +/- 3% vs. 64 +/- 3%, p = 0.05). Exercise echocardiography had the best balance between accuracy and cost for the diagnosis of coronary artery disease in women. CONCLUSIONS: Exercise echocardiography is more specific than exercise electrocardiography for diagnosis of coronary artery disease in women and is a cost-effective approach to the diagnosis of coronary artery disease because of the avoidance of inappropriate angiography.

Adult↗
PubMed1994

Development of an advanced digital image processor for real-time speckle suppression in routine ultrasonic scanning.

This paper describes a digital image processor for ultrasonic speckle suppression that was explicitly designed to satisfy the requirements of detail preservation, adequate smoothing and real-time operation. The first two of these requirements were addressed by selecting a nonlinear adaptive algorithm, which uses a measure of local homogeneity to adjust the amount of smoothing performed at each point of the scan, and employing a large (9 x 9 pixels) filtering window. Real-time operation was achieved by developing a highly concurrent systolic architecture that allowed the efficient mapping of the algorithm into low-cost high-density hardware. Initial experience, obtained by interfacing the processor to a scanner, suggests that this type of processing is capable of enhancing the visibility of subtle differences in echogenicity while retaining genuine image detail, as judged by the preservation of the small vessels and ducts. In addition to its impact on contrast resolution, this form of real-time speckle suppression should also prove valuable as a preprocessing stage before performing other digital image processing operations that are sensitive to noise, such as segmentation and three-dimensional rendering.

Algorithms↗
PubMed1994

A comparison of methods used to calculate ultrasonic myocardial backscatter in the time domain.

The cyclic variation of ultrasonic integrated backscatter from the left ventricular posterior wall and interventricular septum of the heart is now well documented in the literature, with minimal values occurring at end-systole and maximal at end-diastole. However, little work has been performed to date to determine whether cyclic cardiac variation of other, more easily derived, backscatter parameters exists. In this study, 20 baseline, epicardial, long-axis cardiac-cycle sequences were obtained from eight open-chest pigs, yielding a total of 285 ultrasonic frames of RF data, which were analysed off-line on a Sun workstation. In addition, the video data from these studies was digitised and collected from each scan. Five backscatter parameters, calculated in the time-domain, including (1) the average integrated backscatter; (2) the average of the backscatter power from the log-compressed data; (3) the square of the average of the uncompressed radio frequency (RF) amplitude; (4) the square of the average of the RF amplitude from the log-compressed data; and (5) the square of the average grey-scale video data, were analysed and their variation throughout the cardiac cycle correlated against that obtained from integrated backscatter measurements. The backscatter values obtained were referenced to a gel calibration phantom widely used for 2-D calibration studies. Significant (p < 0.001), good correlation existed between the four backscatter parameters derived from the RF data. Reduced correlation was obtained between the video backscatter parameter and those derived from the RF data. Maximum cyclic variation between systole and diastole was measured from the integrated backscatter parameter and minimum from the three log-compressed data sets.

Analog-Digital Conversion↗
PubMed1994

Laparoscopic Incidental Appendectomy: Prevention or Therapy?

This retrospective review describes our experience with the benefits of laparoscopic incidental appendectomy performed in association with various gynecologic procedures. Eighty-five women in the reproductive age group (25 to 48 years of age) were included in this study. Indications for laparoscopy included pelvic pain, pelvic adhesions, and possible endometriosis. There was no immediate or late procedure-related morbidity to the procedure. Visible pathology of the appendix was detected in 16.8% of patients. Of grossly normal appendices, histopathologic examination revealed pathology in 42.4% of cases. Our results suggest that because of the high incidence of pathology in this age group of women, incidental appendectomy at the time of laparoscopy may serve both as a preventive and a therapeutic measure.

Journal Article↗
PubMed1994

Medieval example of cleft lip and palate from St. Gregory's Priory, Canterbury.

An archaeologically retrieved skeleton from medieval Canterbury possibly of the late eleventh or twelfth century, displays clear evidence of cleft lip and palate. A case of cleft palate dating from the seventh century, is known from an Anglo-Saxon cemetery at Burwell. This is the first evidence for both cleft lip and palate in British archaeological material. The individual had survived into adulthood. Apart from an odontome, there was no osseous evidence of any other abnormalities. Artistic evidence of cleft lip dates to the fourth century B.C. and surgical intervention (A.D. 390) is known from China.

Adult↗
PubMed1993

Phase II study of taxol, merbarone, and piroxantrone in stage IV non-small-cell lung cancer: The Eastern Cooperative Oncology Group Results.

BACKGROUND: Patients with metastatic (stage IV) non-small-cell lung cancer usually have a poor prognosis and disease refractory to chemotherapy. Three new agents--taxol, merbarone, and piroxantrone--have shown promising antitumor treatment in vitro and in animals. Taxol is an antimicrotubular agent that interferes with mitosis during cell division. Merbarone, a conjugate of thiobarbituric acid and aniline, is a topoisomerase II inhibitor, which thus inhibits DNA synthesis and tumor growth. Piroxantrone, an anthracenedione derivative, is a DNA intercalating agent that has shown potent antitumor activity in animal studies. PURPOSE: Our randomized phase II study was designed to evaluate the efficacy and toxicity of these agents in the treatment of stage IV metastatic non-small-cell lung cancer. METHODS: Eligible patients (119) were randomly assigned to receive one of the three treatments given every 3 weeks: 250 mg/m2 taxol by a 24-hour intravenous infusion, 1000 mg/m2 merbarone by continuous intravenous infusion through a central catheter daily for 5 days, or 150 mg/m2 piroxantrone by intravenous infusion over 1 hour. Patients had received no chemotherapy. Response and toxicity were evaluated every 3 weeks. RESULTS: Twenty-five patients were randomly assigned to receive taxol, 47 to receive merbarone, and 47 to receive piroxantrone. One of 44 assessable patients (2.3%) treated with piroxantrone had a complete response. Rates for partial response were 20.8% (five of 24 patients) and 5.7% (two of 35) for assessable patients treated with taxol or merbarone, respectively. One-year survival rates were 41.7%, 21.6%, and 22.6%, and median survival times were 24.1, 19.9, and 29.3 weeks for taxol, merbarone, and piroxantrone, respectively. These differences were not statistically significant, but this study was not designed to compare survival. In general, toxicity was manageable. With premedication, no anaphylaxis was observed with taxol. The most common toxic effects were leukopenia with taxol or piroxantrone treatment and thromboembolic complications with merbarone. Death directly related to treatment occurred in 4% (one patient), 11.4% (four), and 5% (two) of the assessable patients receiving taxol, merbarone, and piroxantrone, respectively. Cardiotoxicity and neurotoxicity occurred only occasionally in all three arms. CONCLUSION: On the basis of the response rate (20.8% partial response) and 1-year survival rate (41.7%), taxol is an active agent for the treatment of metastatic non-small-cell lung cancer. Merbarone and piroxantrone are relatively inactive. IMPLICATIONS: Further study of taxol is warranted. In future studies, taxol should be combined with other agents, and granulocyte colony-stimulating factor should be used to ameliorate myelosuppression.

Adult↗