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Biomedical subjects

W Ott

Publications and source records attributed to W Ott.

At least 19 recordsLinked to original sources
PubMed2001

Reoperative coronary bypass surgery using normothermic cardiopulmonary bypass: comparison with first-time procedures.

Redo coronary artery bypass grafting (CABG) is characterized by increased patient risk compared with first-time CABG. The reason for higher risk is not completely understood but it is logically related to inadequate myocardial preservation evidenced by the higher incidence of postoperative low-output syndrome. We compared normothermic cardiopulmonary bypass with cold blood maintenance cardioplegia in both first-time and redo CABGs to determine whether this single approach is appropriate for both instances. Five hundred seventeen consecutive CABG patients were retrospectively reviewed. Four hundred fifty-four first-time CABG procedures were compared with 44 redo procedures. All aspects of the operation were identical including myocardial preservation. Retrospective univariant analysis of both groups followed. Three clinical features distinguished first-time versus redo CABG. These were previous percutaneous transluminal coronary angioplasty (first-time 19% vs redo 71%; P < 0.001), preoperative intra-aortic balloon pump (first-time 38% vs redo 71%; P < 0.001), and Parsonnet risk score (first-time 11.7+/-8.2 vs redo 19.2+/-8.8; P < 0.001). Operative mortality for redo CABG was higher than in first-time procedures (3.4% vs 6.4%; P = not significant), although small sample size limited statistical significance. The length of stay was statistically longer in redo patients (8.7+/-10.8 vs 6.0+/-5.1 days; P < 0.01) and is related to a higher Parsonnet score, increased postoperative pneumonia, and failed percutaneous transluminal coronary angioplasty before redo CABG. We conclude that redo CABG is a different operation from first-time procedures and requires enhanced myocardial preservation. Normothermic cardiopulmonary bypass with cold blood maintenance cardioplegia does not appear to achieve this goal.

Aged↗
PubMed2000

Predicting particulate (PM10) personal exposure distributions using a random component superposition statistical model.

This paper presents a new statistical model designed to extend our understanding from prior personal exposure field measurements of urban populations to other cities where ambient monitoring data, but no personal exposure measurements, exist. The model partitions personal exposure into two distinct components: ambient concentration and nonambient concentration. It is assumed the ambient and nonambient concentration components are uncorrelated and add together; therefore, the model is called a random component superposition (RCS) model. The 24-hr ambient outdoor concentration is multiplied by a dimensionless "attenuation factor" between 0 and 1 to account for deposition of particles as the ambient air infiltrates indoors. The RCS model is applied to field PM10 measurement data from three large-scale personal exposure field studies: THEES (Total Human Environmental Exposure Study) in Phillipsburg, NJ; PTEAM (Particle Total Exposure Assessment Methodology) in Riverside, CA; and the Ethyl Corporation study in Toronto, Canada. Because indoor sources and activities (smoking, cooking, cleaning, the personal cloud, etc.) may be similar in similar populations, it was hypothesized that the statistical distribution of nonambient personal exposure is invariant across cities. Using a fixed 24-hr attenuation factor as a first approximation derived from regression analysis for the respondents, the distributions of nonambient PM10 personal exposures were obtained for each city. Although the mean ambient PM10 concentrations in the three cities varied from 27.9 micrograms/m3 in Toronto to 60.9 micrograms/m3 in Phillipsburg to 94.1 micrograms/m3 in Riverside, the mean nonambient components of personal exposures were found to be closer: 52.6 micrograms/m3 in Toronto; 52.4 micrograms/m3 in Phillipsburg; and 59.2 micrograms/m3 in Riverside. The three frequency distributions of the nonambient components of exposure also were similar in shape, giving support to the hypothesis that nonambient concentrations are similar across different cities and populations. These results indicate that, if the ambient concentrations were completely controlled and set to zero in all three cities, the median of the remaining personal exposures to PM10 would range from 32.0 micrograms/m3 (Toronto) to 34.4 micrograms/m3 (Phillipsburg) to 48.8 micrograms/m3 (Riverside). The highest-exposed 30% of the population in the three cities would still be exposed to 24-hr average PM10 concentrations of 47-74 micrograms/m3; the highest 20% would be exposed to concentrations of 56-92 micrograms/m3; the highest 10% to concentrations of 88-131 micrograms/m3; and the highest 5% to 133-175 micrograms/m3, due only to indoor sources and activities. The distribution for the difference between personal exposures and indoor concentrations, or the "personal cloud," also was similar in the three cities, with a mean of 30-35 micrograms/m3, suggesting that the personal cloud accounts for more than half of the nonambient component of PM10 personal exposure in the three cities. Using only the ambient measurements in Toronto, the nonambient data from THEES in Phillipsburg was used to predict the entire personal exposure distribution in Toronto. The PM10 exposure distribution predicted by the model showed reasonable agreement with the PM10 personal exposure distribution measured in Toronto. These initial results suggest that the RCS model may be a powerful tool for predicting personal exposure distributions and statistics in other cities where only ambient particle data are available.

Air Pollution↗
PubMed1997

Thyroid volume and urinary iodine in European schoolchildren: standardization of values for assessment of iodine deficiency.

Up to 1992, most European countries used to be moderately to severely iodine deficient. The present study aimed at evaluating possible changes in the status of iodine nutrition in 12 European countries during the past few years. Thyroid volume was measured by ultrasonography in 7599 schoolchildren aged 7-15 years in one to fifteen sites in The Netherlands. Belgium, Luxemburg, France, Germany, Austria, Italy, Poland, the Czech and Slovak Republics, Hungary and Romania. The concentrations of urinary iodine were measured in 5709 of them. A mobile unit (ThyroMobil van) equipped with a sonographic device and facilities for the collection of urine samples visited all sites in the 12 countries. All ultrasounds and all urinary iodine assays were performed by the same investigators. The status of iodine nutrition in schoolchildren has markedly improved in many European countries and is presently normal in The Netherlands, France and Slovakia. It remains unchanged in other countries such as Belgium. There is an inverse relationship between urinary iodine and thyroid volume in schoolchildren in Europe. Goiter occurs as soon as the urinary iodine is below a critical threshold of 10 micrograms/dl. Its prevalence is up to 10 to 40% in some remote European areas. This work produced updated recommendations for the normal volume of the thyroid measured by ultrasonography as a function of age, sex and body surface area in iodine-replete schoolchildren in Europe. This study proposes a method for a standardized evaluation of iodine nutrition on a continental basis, which could be used in other continents.

Adolescent↗
PubMed1996

Daily exposure to environmental tobacco smoke: smokers vs nonsmokers in California.

OBJECTIVES: This study examined the differences in environmental tobacco smoke exposure between smokers and non-smokers. METHODS: A probability sample of 1579 California adults completed a 1-day time diary of a full day's activities in which they reported whether any smoker was present during each activity. RESULTS: Some 61% of respondents reported at least some environmental tobacco smoke exposure in these diary accounts (for an average of up to 5 hours per day), and potential exposure rose monotonically with number of cigarettes actively smoked. Heaviest smokers reported about four times as much such exposure as nonsmokers. CONCLUSIONS: Because smokers lead life-styles that expose them to far higher levels of environmental tobacco smoke exposure, that factor needs to be controlled in studies estimating the effects of active smoking.

Adolescent↗
PubMed1994

Carbon monoxide exposures inside an automobile traveling on an urban arterial highway.

Carbon monoxide (CO) exposures were measured inside a motor vehicle during 88 standardized drives on a major urban arterial highway, El Camino Real (traffic volume of 30,500-45,000 vehicles per day), over a 13-1/2 month period. On each trip (lasting between 31 and 61 minutes), the test vehicle drove the same 5.9-mile segment of roadway in both directions, for a total of 11.8 miles, passing through 20 intersections with traffic lights (10 in each direction) in three California cities (Menlo Park, Palo Alto, and Los Altos). Earlier tests showed that the test vehicle was free of CO intrusion. For the 88 trips, the mean CO concentration was 9.8 ppm, with a standard deviation of 5.8 ppm. Of nine covariates that were examined to explain the variability in the mean CO exposures observed on the 88 trips (ambient CO at two fixed stations, atmospheric stability, seasonal trend function, time of day, average surrounding vehicle count, trip duration, proportion of time stopped at lights, and instrument type), a fairly strong seasonal trend was found. A model consisting of only a single measure of traffic volume and a seasonal trend component had substantial predictive power (R2 = 0.68); by contrast, the ambient CO levels, although partially correlated with average exposures, contributed comparatively little predictive power to the model. The CO exposures experienced while drivers waited at the red lights at an intersection ranged from 6.8 to 14.9 ppm and differed considerably from intersection to intersection.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollution, Indoor↗
PubMed1984

[Causes of accidents and injuries in cross-country skiing].

335 cross-country skiing accidents which occurred during the last five skiing seasons, are evaluated. The overall number of accidents has increased slightly. Their severity and incidence depends significantly on the age and state of training of the injured person. Typical fractures are most frequent at the upper extremity, whereas damage of the capsular ligament of the knee joint is by far the most frequent lesion at the lower extremity. Severe and extremely severe injuries occur besides many trifling ones.

Adult↗
PubMed1981

[Peritonitis in acute appendicitis: prognostic aspects, personal results].

One of the most frequent causes for peritonitis is acute appendicitis. Extent and degree of peritonitis determine the further course of the disease. A retrospective analysis of acute appendicitis with concomitant peritonitis relates pre- and intraoperative findings to the postoperative development. Resulting aspects may simplify therapy in special cases and permit a more reliable prognosis.

Adolescent↗
PubMed1981

[Therapy of purulent peritonitis. Documentation of 78 cases and experience with taurolin (author's transl)].

From three different surgical departments 78 patients with purulent peritonitis are analyzed according to cause, origin, and extent of peritonitis. Operative therapy is presented. As additional antibacterial therapy the new chemotherapeutic agent, Taurolin, with antiendotoxin-effect is used. The postoperative course (temperature exceeding 38 degrees C, secondary wound healing, day of discharge, and serious complications) is correlated with pre- and intraoperative parameters; for instance, 1. postoperative fever occurs in one half of the patients, more frequently following perforation of stomach and duodenum; 2. every second patient shows secondary wound healing, this happens even more often in peritonitis arising from biliary disease or appendicitis; 3. in 29.5% of the patients serious complications arise, especially in patients with peritonitis originating in stomach, small intestine or large bowel; 4. overall mortality of 11.5% is surpassed in patients with peritonitis originating from small intestine or large bowel. The so-called peritonitis-index (calculated on the basis of pre- and intraoperative factors) shows a significant difference between survivors and patients dying during the postoperative course. In 80% of the 78 patients with purulent peritonitis taurolin was effective as a substitute for the usual antibiotics.

Adult↗
PubMed1981

[Human albumin or dextran 60 for the restoration of the blood volume, with special reference to the colloid osmotic pressure (author's transl)].

The high cost and limited availability of human albumin as a plasma substitute make it desirable to limit its use to special cases and to replace it by inexpensive and easily obtainable colloids. Patients about to undergo major abdominal surgery were given either human albumin or dextran 60 during the operation and for three days afterwards. Although both groups received the same quantity of colloidal plasma substitutes they differed significantly in respect to the serum albumin and protein concentrations. However, the osmotic pressure, for the maintenance of which the albumin fraction is mainly responsible, showed a marked fall in both groups, indicating that human albumin is not superior to dextran. All other parameters, particularly the clotting mechanism, remained within the normal range and did not differ between the two groups. The results of the study, in conjunction with the known facts regarding the metabolism and function of albumin, suggest that dextran 60 can adequately replace human albumin in a large number of cases. Great importance belongs to measurement of the colloid osmotic pressure.

Blood Proteins↗