Continuous recording of urethral activity in healthy female volunteers

The pressure variations at the maximal urethral closure pressure (MUCP) were continuously recorded in healthy female volunteers by means of a two-point microtip transducer catheter for one hour. Before the investigation a normal voiding was assured objectively and bladder instability was excluded. All women showed pressure variations both at the MUCP and more distally. The pressure variations, from 3 to 66 cm H₂O, showed rhythmicity and three frequency ranges could be identified. Slow pressure waves with a frequency of one in eight to 19 minutes were observed. Relatively fast-pressure waves were observed (one every one to four minutes) and relatively fast-frequency pressure waves were observed (rate: one to eight per minute). The pressure variations of the urethra seem to be an aspect of normal urethral physiology possibly contributing to continence and urinary tract infection prevention.     

Exhaled gas analysis. Technical and clinical aspects of capnography and oxygen consumption

Infrared absorption and mass spectrometry represent two common techniques used for measurement of end-tidal carbon dioxide concentration in expired air. Continuous capnographic monitoring may be useful in assessing changes in ventilation, pulmonary blood flow, and metabolism. Accuracy may be affected by the type of gas sampling technique used, as well as altered ventilation and perfusion matching in the lung. Oxygen uptake at the mouth may be measured by either an open- or closed-circuit technique. Calculated values of oxygen consumption obtained from pulmonary artery catheter data and blood gases correlate well with direct gas measurement. Accurate bedside determination requires a thorough knowledge of equipment and proper gas collection, especially at high inspired oxygen levels. This information may be useful in nutritional assessments, during mechanical ventilation, and in evaluation of therapeutic interventions aimed at optimizing peripheral oxygen delivery.     

Is Coronary Graft Doppler More Sensitive for Indiviual Graft Flows Than TEE During CABG Surgery?

Abstract    In this case report we describe a situation where despite a normal TEE exam immediately postcardiopulmonary bypass, there was no flow in the left internal mammary artery graft to the left anterior descending artery. This was picked up by coronary Doppler and subsequently repaired.     

Pseudophakic bullous keratopathy

The number of cataract extractions in Switzerland has tripled since 1981. In 1986, a total of 15,500 cataract operations were performed, 95% of which were accompanied by an intraocular lens implantation. In spite of this tremendous increase pseudophakic bullous keratopathy remains a rare indication for keratoplasties: between 1980 and 1986 only 20 grafts were performed at the authors' clinic for irreversible corneal edema following lens implantation. After implantation of posterior chamber lenses, penetrating keratoplasty for corneal decompensation is performed after a significantly shorter period (one year) than with anterior chamber lenses (three years), or in iris-supported lenses (four years). In Switzerland, the incidence of pseudophakic bullous keratopathy among patients with posterior chamber lenses is around 0.1 to 0.3%. A long-term investigation of the endothelial cell density over a period of seven years in 16 patients with a Binkhorst two-loop lens revealed a quite stable and satisfactory cell density of 1600 cells/mm2.     

Biomonitoring of benzene exposure by trace analyses of phenylguanine

Summary From preliminary experiments it was known that radiolabelled benzene and some of its metabolites during its metabolic activation process produce different in vitro DNA-phenyladducts in mitoplasts [5, 11].As we reported previously [9] at least one of these adducts, N-7-phenylguanine, is excreted in the urine of rats in measurable amounts, probably through an excision-repair mechanism after an inhalation experiment. Now we found, after i.p. application of benzene in the urine of rats, a compound separated by cation-exchange chromatography that behaves like a synthezised N-7-phenylguanine reference substance with respect to its retention index and the UV-absorption. This finding could be confirmed by HPLC-measurements with reversed-phase carrier materials. Silylation and gaschromatographic/mass spectrometric (GC/MS) separation of the fraction, which contains the phenylguanine, revealed that these fractions contain further phenyl adducts. Furthermore we studied the time-dependent excretion of the DNA-base adduct. Surprisingly the excretion dropped to zero on the fourth day and showed a new increase thereafter.     

Pediatric ophthalmology: reasons for examination and disease pictures

A representative sample of 800 patients was taken from 15,000 children treated between 1972 and 1984 in the Department of Pediatric Ophthalmology of Frankfurt University Eye Hospital. Their charts were reviewed to answer two questions: what are the most frequent reasons for ophthalmological examination in children under 15 years old and what are the most frequent diagnoses? Ophthalmological examinations were most frequently scheduled because of strabismus, errors of refraction and trauma or inflammation of the anterior segment, though also in a large number of cases because of general diseases, most often neurologic diseases such as epilepsy or elevated intracerebral pressure. The diseases diagnosed ophthalmologically were classified as congenital or acquired eye diseases and congenital or acquired general diseases with ocular symptoms. The most frequent are indicated in the text. Acquired diseases were more frequent than congenital diseases, though this group proved to be much larger in pediatric patients than in adult patients.     

An optimal three-stage design for phase II clinical trials

A phase II clinical trial in cancer therapeutics is usually a single-arm study to determine whether an experimental treatment (E) holds sufficient promise to warrant further testing. When the criterion of treatment efficacy is a binary endpoint (response/no response) with probability of response p, we propose a three-stage optimal design for testing H₀: p ≤ p₀ versus H₁: p ≥ p₁, where p₁ and p₀ are response rates such that E does or does not merit further testing at given levels of statistical significance (α) and power (1 ? β). The proposed design is essentially a combination of earlier proposals by Gehan and Simon. The design stops with rejection of H₁ at stage 1 when there is an initial moderately long run of consecutive treatment failures; otherwise there is continuation to stage 2 and (possibly) stage 3 which have decision rules analogous to those in stages 1 and 2 of Simon's design. Thus, rejection of H₁ is possible at any stage, but acceptance only at the final stage. The design is optimal in the sense that expected sample size is minimized when p = p₀, subject to the practical constraint that the minimum stage 1 sample size is at least 5. The proposed design has greatest utility when the true response rate of E is small, it is desirable to stop early if there is a moderately long run of early treatment failures, and it is practical to implement a three-stage design. Compared to Simon's optimal two-stage design, the optimal three-stage design has the following features: stage 1 is the same size or smaller and has the possibility of stopping earlier when 0 successes are observed; the expected sample size under the null hypothesis is smaller; stages 1 and 2 generally have more patients than stage 1 of the two-stage design, but a higher probability of early termination under H₀; and the total sample size and criteria for rejection of H₁ at stage 3 are similar to the corresponding values at the end of stage 2 in the two-stage optimal design.     

MR imaging, flow and motion.

The present work is intended as a nonmathematical review of the role of flow and motion in nuclear magnetic resonance (MR) imaging. A historical review of MR flow measurement techniques is given, followed by a short overview of flow models in vitro and in vivo. The theory behind the influence of motion on the modulus and phase MR signal information is discussed and effects such as washin/washout, flow-induced signal void, phase offset, and phase dispersion are defined. A simple approach to the concept of MR angiography is given, and methods for quantitative flow measurements such as the phase mapping technique, are surveyed. Aspects of the measurement of diffusion and microcirculation are given, and finally, an overview of the role of MR flow imaging in present and future clinical application is given.