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Biomedical subjects

P Winkel

Publications and source records attributed to P Winkel.

At least 37 records · Page 2Linked to original sources
PubMed1988

Adjusted-dose intravenous heparin treatment evaluation of an automated and a non automated schedule.

An automated schedule for adjusted continuous intravenous heparin treatment was tested under physician supervision in 19 patients and the results were compared to those obtained in 27 patients treated prior to automation. Both schedules used plasma activated partial thrombo-plastin time (P-APTT) for adjustment of heparin infusion and aimed at the same therapeutic interval for P-APTT (1.5-2 times the value in normal pooled plasma). The quality of treatment was assessed on the basis of clinical information and its ability to keep the P-APTT within or close to the therapeutic interval. The automated schedule reduced the involvement of the physician by 73% without changing the quality of treatment or increasing the consumption of other resources such as the number of P-APTT analyses. Both schedules were able to keep the P-APTT of the patients within the therapeutic interval for about 40% of the treatment time.

Adolescent↗
PubMed1988

The Danish Breast Cancer Group (DBCG) biochemical tumor marker program.

One hundred and thirty-three high-risk breast cancer patients entered the DBCG (Danish Breast Cancer Cooperative Group) tumor marker program between May 1978 and June 1980. Eleven were excluded from the DBCG protocol and 23 left the program prematurely. The remaining patients were seen at the clinical laboratory once a month during the first year and every third month during the second and third year following mastectomy. Blood and urine specimens were collected and plasma, serum and urine specimens stored at -80 degrees C. The purposes of the program were 1) to collect a biological material which may later be used to assess the usefulness of biochemical markers for the prediction of recurrence and 2) to develop statistical time series models suitable for this assessment. Such a model is presented and its application for the assessment of the usefulness of 14 common tumor markers reviewed. Only P-CEA proved to be of any value but its usefulness was marginal.

Biomarkers, Tumor↗
PubMed1988

Health effects of toluene exposure.

The impact of industrial toluene exposure was assessed in 262 male employees of two Danish photographic printing plants. The study involved assessment of acute and chronic exposure based on a scoring system, standardised questions, measurement of blood pressure, pulmonary functions, and the plasma concentrations of urate, creatinine, creatine kinase, alanine-aminotransferase, FSH, LH, testosterone, sexual hormone binding globulin, thyroxine, triiodothyronine, and cortisole (following synacthen). The potentially confounding factors: age, weight, height, alcohol consumption and tobacco smoking were included in statistical analysis which showed that systolic blood pressure (p less than 0.01), P-P-FSH (p less than 0.001), dizziness (p less than 0.0001), decreased ability to concentrate (p less than 0.001), and dizziness during the past year (p less than 0.01) were correlated with the exposure score. Following six weeks without exposure, systolic blood pressure and P-ALAT decreased, the latter being correlated with the exposure score.

Adult↗
PubMed1987

Plasma sex hormones and ischemic heart disease.

The reason why men have a higher incidence of ischemic heart disease than women, and women rarely develop ischemic heart disease before the menopause, is not known. However, elevated plasma estradiol and estrone concentrations have been found in men surviving myocardial infarction. Hence, hyperestrogenemia has been suggested as a coronary risk factor. To assess this theory we review the literature on sex steroid production, the relationship between established coronary risk factors and plasma sex hormones, as well as results from clinical trials in which estrogens have been administered to men and women. Other possible explanations why plasma estradiol levels are elevated in male survivors of myocardial infarction are discussed. Based on earlier and recent evidence, it is hypothesized that the elevated plasma estradiol concentration found in men surviving myocardial infarction is due to either the myocardial infarction itself or established risk factors such as smoking or hypertension.

Androstenedione↗
PubMed1987

Utilization review and management of laboratory testing in the ambulatory setting.

Physicians are probably guilty of misusing the clinical laboratory by either ordering too many tests (overutilization) or ordering too few tests (underutilization). This article is concerned mainly with overutilization in terms of searching for asymptomatic disease, too frequent monitoring of tests, ordering of test clusters, and a failure to use available information. The strategies considered to decrease overutilization include educational strategies, audit with feedback, cost-awareness strategies, rationing strategies, financial incentives and risk-sharing strategies, changes in the test request procedures, and administrative mandates of set protocols for laboratory test ordering.

Ambulatory Care↗
PubMed1985

The relative merit of various cytochemical quantities and manual differential count in predicting remission following chemotherapy of patients with de novo acute myeloblastic leukemia.

Eighteen patients with acute myeloblastic leukemia were monitored using an automated differential analyzer (Hemalog D). Twelve patients achieved complete remission. The fraction of large unstained cells (LUC), lymphocytes (LYMPH), the ratio LUC/LYMPH, WBC, and LUC X WBC as measured on day 12 following start of induction chemotherapy differed significantly between patients who did not respond and patients who did achieve remission. The quantity LUC/LYMPH was by far the best discriminator. In patients who achieved remission, the median value was 0.047 and the range was 0.017-0.088. In patients who did not, the corresponding values were 0.163 and 0.12-0.32. Hemalog D examination of peripheral blood on day 12 after initiation of treatment thus seems to give an early prediction of remission as defined by morphologic examination of bone marrow.

Acute Disease↗
PubMed1985

Reliability of the Hitachi sodium and potassium electrodes assessed.

We compared the Hitachi 705 E sodium/potassium electrode system with the Radiometer flame photometer for measuring concentrations of sodium and potassium ions in serum and plasma. Our data show that the Hitachi results are slightly but significantly (less than 0.001) lower than the flame photometer results: Na+ 1.33 mmol/L for serum and 2.24 mmol/L for plasma; K+ 0.062 mmol/L for serum and 0.082 mmol/L for plasma. The magnitude of the bias varied considerably from day to day, ranging from -0.10 to 2.33 mmol/L for Na+ in serum and from 0.00 to 0.11 mmol/L for serum K+; for plasma specimens the corresponding ranges were -0.03 to 5.97 mmol/L and 0.00 to 0.17 mmol/L. These variations probably reflected difficulties in reproducing the calibration from day to day, because the daily means for a serum pool varied in parallel. We occasionally encountered serious problems with reproducibility.

Autoanalysis↗
PubMed1984

Assessing cost savings when unnecessary utilization of laboratory tests can be abolished.

The authors report on the theoretic cost savings that would be realized if presumed overutilization of selected laboratory tests could be eliminated. They limit the scope of this study to inpatients at the University Hospital and on a preselected subset of assays ordered in their institution. A baseline audit including the requests for 19 commonly ordered clinical chemistry tests made for all inpatients during three weekdays was performed at our 400-bed hospital. Eight of the 19 tests (the LYTES-Plus), were done on the ASTRA-8 selective multitest analyzer (Beckman Instruments Inc., Brea, CA 92621), while remaining 11 tests (MTA-11) were performed on the RA-1000 selective multitest system (Technicon Instruments Corp., Tarrytown, NY 10591). The average tests ordered per patient-day were 4.38 of the 19, and the average venipunctures were 0.67. The corresponding numbers for the intensive care patients were 16.6 tests and 2.45 venipunctures per patient-day. Although the intensive care units contributed approximately 8% of the patient days in the hospital, they represented more than 25% of the tests ordered. The authors noted that 5.89 of the eight possible LYTES-Plus assays were ordered per ASTRA-8 sample. The equivalent figure for MTA-11 was 4.55 of 11 possible tests. Using list prices of reagents and disposables, the savings in direct material costs resulting from implementing a number of rather conservative recommendations for decreasing overutilization was estimated to be $45,000 per annum or 31% of the total direct material costs.

Blood Chemical Analysis↗
PubMed1984

The effects of carbamazepine and valproate on folate metabolism in man.

The effect of carbamazepine and valproate treatment on folate metabolism was studied in 11 epileptic patients. The absorption of folic acid and of Pteroyl-gamma-L-glutamyl-gamma-L-glutamyl-L-glutamic acid, a synthetic substrate for intestinal folate deconjugase , was measured prior to and after 2 months of antiepileptic therapy with either carbamazepine (5 cases) or valproate (6 cases). After 2 months' treatment, the area under plasma concentration versus time curve was significantly decreased and t-max (time when maximal plasma concentration is obtained) was significantly prolonged. No inhibition of intestinal folate deconjugation was observed and the liver metabolism of folic acid was found to be unaffected by the treatment. These findings are interpreted as an inhibition of intestinal folic acid absorption caused by the antiepileptic therapy.

Adolescent↗
PubMed1984

Operational research and cost containment: a general mathematical model of a workstation.

To facilitate planning and management, I have derived a mathematical model describing the dynamics of a workstation that receives a mixture of routine and emergency specimens. The model parameters include the maximal specimen-processing rate (to be defined by personnel representatives) and the longest delay allowed for emergency specimens at the workstation. Based on the model, a computer-simulation technique has been developed to maximize the length of time (planned pauses) during which the workstation could be closed without causing undue delay of routine and emergency specimen results. The application of this technique is illustrated with real data, in which more than 50% of the specimens were emergency specimens. Three pauses, constituting 35% of working hours, could be introduced with a negligible impact on the turnaround time of emergency specimens (mean increase = 8 min). The model may also be used to derive, as a function of time of day, the largest extra workload that may be presented to a workstation without creating overwork. The workload could be increased by 45%, provided that all additional specimens arrived before noon.

Cancer Care Facilities↗
PubMed1984

Reference values: are they useful?

To answer the question of whether reference values are useful in clinical decision-making, this article addresses the following major controversies: (1) Are reference subjects representative of the group from which they are selected? (2) To what extent should the process of collecting reference values be standardized and controlled? (3) Can a single distribution of reference values be used in an meaningful way in the process of clinical decision-making.

Clinical Laboratory Techniques↗
PubMed1983

The value of routine biochemical and surgical pathology quantities in predicting recurrence in high-risk patients following surgery for primary breast cancer.

The initial biochemical data (serum[S]-carcinoembryonic antigen, S-lactate dehydrogenase, S-gammaglutamyl transferase, S-alkaline phosphatase urine[U]-creatinine, and three urinary quantities related to collagen metabolism) and surgical pathology data (tumor size, grade of tumor anaplasia, number of positive lymph nodes, number of negative lymph nodes) were examined in 52 consecutive postmenopausal risk group II patients operated for primary breast cancer without metastatic disease (mastectomy + partial axillary resection) who participated in the Danish Breast Cancer Group's controlled clinical trial of radiation (RT) alone, and RT + levamisol. The follow-up (mean = 3.45 years, range = 3-4 years) included physical examination every three months, x-ray of chest, bone scan, and x-ray of axial skeleton every six months. Recurrence was defined as metastatic disease detected during the first three years of postoperative follow-up study. Twenty patients had recurrences. A stepwise discriminant analysis of the surgical pathology quantities showed that all quantities except tumor size contributed significantly (P less than 0.01) to the discrimination between controls (no recurrence after 3-4 years) and patients who had recurrences within three years. When each of the biochemical quantities was combined with the surgical pathology data it was found that only urinary total hydroxy-proline to creatinine ratio improved the discrimination significantly (P less than 0.05) and that the effect was marginal.

Aged↗
PubMed1982

Coronary risk factors and plasma sex hormones.

Recent studies have reported higher plasma estradiol levels in male survivors of acute myocardial infarction. This finding has raised the possibility that hyperestrogenemia may consitiute a separate coronary risk factor. In 443 men, aged 30, 40, 50, and 60, we assessed the relationship between plasma levels of estradiol, testosterone, and testosterone-binding globulin and coronary risk factors: fasting plasma concentrations of triglyceride, cholesterol, and high-density lipoprotein, blood pressure, and smoking and leisure-time physical activity patterns. Plasma estradiol concentrations were found to correlate significantly with body weight. After adjustment for this association, we found that the mean plasma estradiol concentration still was significantly higher in smokers than in nonsmokers. No other correlation could be estabilished between plasma hormone levels and coronary risk factors. The relative hyperestrogenemia reported in men with previous myocardial infarction may be due to an effect of smoking but may also reflect the relationship between body weight and plasma estradiol levels. Future studies should consider the demonstrated association between plasma estrogen levels and smoking.

Adult↗
PubMed1982

Automated cytochemistry in the prediction of remission following chemotherapy of patients with de novo acute myeloblastic leukemia.

In seven patients with de novo acute myeloblastic leukemia, the concentration of large unstained cells (LUC) in peripheral blood and the ratio between this quantity and the concentration of lymphocytes (LUC/LYMPH) were measured at short intervals during each patient's clinical course. An automated differential analyzer (the Hemalog-D) was used. Both quantities were significantly higher 12 days after the institution of daunomycin and cytosine arabinoside chemotherapy (between first and second treatment series when all patients were pancytopenic) in three of the patients who did not achieve remission (mean LUC = 59 cells/microliter, mean LUC/LYMPH = 13.9), as compared with four of the patients who went into remission following two series of chemotherapy (mean LUC = 16 cells/microliter, mean LUC/LYMPH = 3.11).

Aged↗
PubMed1982

Usefulness of clinical chemistry measurements in classifying patients with breast cancer.

Laboratory measurements can be used to detect, classify, and monitor patients with breast cancer. This review covers in detail the clinical usefulness of carcino embryonic antigen, tissue polypeptide antigen, various glycoproteins, pregnancy-associated proteins, casein, lactalbumin, beta-2-microglobulin, ferritin, immunoglobins, acute phase proteins, placental-like alkaline phosphatase, liver-associated enzymes, glycosyltransferases, human chorionic gonadotropin, calcitonin, polyamines, and collagen breakdown products, in relationship to their diagnostic utility in patients suspected of having or known to have breast cancer. In addition, these authors assess the merits of various multivariate techniques using a number of clinical chemistry quantities in the same regard. Finally, the relative contribution of biochemical tests vs. the information values gained from "surgical pathology" data (number of positive nodes, number of negative nodes, and degree of anaplasia) is discussed.

Alkaline Phosphatase↗
PubMed1982

Predicting recurrence in patients with breast cancer from cumulative laboratory results: a new technique for the application of time series analysis.

We followed the cases of 26 consecutive postmenopausal patients operated on for primary breast cancer. Serum specimens were obtained each month for 1.5 years and stored at -80 degrees C until assayed for carcinoembryonic antigen (CEA) and other quantities. Ten patients developed recurrence, while 16 qualified as controls (no clinical recurrence for at least 1.7 years after the last venipuncture). Using the homeostatic autoregressive time series model, modified by us to be particularly sensitive to sustained deviations from the mean, we detected four recurrences by CEA without having any falsely positive alarms. Group-based reference limits and application of the unmodified homeostatic model were less effective (fewer detected and shorter lead time). Simulation studies, involving use of a mathematical model relating CEA concentration to tumor growth and using parameters estimated from patient data, verified this and indicated that at least five stable baseline values are needed to detect 100% of recurrences before they are detected by the group-based limit.

Aged↗