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Biomedical subjects

F Dunn

Publications and source records attributed to F Dunn.

At least 73 records · Page 4Linked to original sources
PubMed1981

Ultrasonically induced, in vivo morphological damage in mouse testicular tissue.

Mouse testes were exposed in vivo to 1 MHz continuous wave ultrasonic energy for 30 sec at spatial peak intensities of either 2 or 5 W/cm2. Following exposure they were surgically removed at times ranging from immediate (within 60 sec) to 63 days, and histologically prepared for optical microscopy examination. The observed alterations can be classified according to the number and type of affected cell layers in the tubule. Leydig cells were unaffected, and some alterations differed from those previously seen at higher ultrasonic exposure intensities or at much longer exposure times.

Animals↗
PubMed1980

Ultrasonics propagation properties of collagen.

Ultrasonic absorption measurements in the range 0.5--56 MHz, and measurements of velocity at 8.87 MHz, were made in collagen suspensions in which molecular integrity was preserved, in a range of concentrations 0.07--0.7% by weight, at 10 and 20 degrees C. Absorption and velocity values, per unit concentration, exhibited by collagen are much greater in magnitude than those exhibited by globular proteins.

Animals↗
PubMed1979

The Scottish perinatal mortality survey.

Perinatal deaths in single births that occurred in Scotland during 1977 were investigated by case-record analysis. Causes of death were divided into nine categories, an extended version of the Aberdeen classification being used. Out of 1012 single perinatal deaths, 265 were due to fetal abnormality, which in 140 cases was malformation of the central nervous system. Of the 747 normally formed infants, 446 weighed 1500 g or more, of whom 82 died intra partum and 154 were born alive. The largest single cause of death was low birth weight in normally formed babies whose mothers had no complications of pregnancy (302 cases). Of these babies, 103 (34%) were growth-retarded. Rhesus incompatibility (16 deaths) and maternal diabetes (seven deaths) were not major causes of perinatal loss. These results were thought to be valuable in illustrating the main causes of perinatal mortality and directing attention to important issues. Hence a modified version of the study is being continued to see whether yearly audit by regional assessors is a feasible and practical way of monitoring trends in perinatal mortality.

Birth Weight↗
PubMed1978

Frequency dependence of ultrasonic absorption in mammalian testis.

The earlier report that the frequency dependence of ultrasonic absorption of mammalian testis memicked a single relaxation process is explained as an effect of ultrasonic beam width upon the transient thermoelectric technique. More detailed measurements show that the frequency dependence of the ultrasonic absorption in testis is much the same as the attenuation in other soft tissues, viz., a proportional to f1.1. The earlier finding that testis exhibits an ultrasonic absorption coefficient significantly lower than reported for other tissues is confirmed.

Animals↗
PubMed1978

Comprehensive compilation of empirical ultrasonic properties of mammalian tissues.

A detailed review of the literature on ultrasonic propagation properties of mammalian tissues and organs has revealed 144 papers containing compilable data. Over 1300 lines of parametric data are listed, including the tissue, species, age, specimen preparation, anatomical structure, pathology, temperature, measurement method, frequency, velocity, attenuation, acoustic impedance, and density.

Animals↗
PubMed1976

Ultrasonic absorbed dose, dose rate, and produced lesion volume.

Histological preparations of ultrasonically produced lesions in cat brain, at 3 and 4 MHz, have been studied microscopically. The relationship of the delivered acoustic intensity at the lesion site, the energy absorbed per unit volume of the lesion, and the lesion volume is exhibited. It is suggested that universal responses to ultrasonic exposure may exist for different tissues.

Animals↗
PubMed1976

Serial 3 orthogonal lead electrocardiographic abnormalities after pulmonary embolism. Computer assisted study.

The 3 orthogonal lead electrocardiogram has been evaluated with computer assisted interpretation in 20 patients with acute pulmonary embolism confirmed by pulmonary angiography. Initial 3-lead electrocardiographic abnormalities were found to be at least as helpful as the 12-lead electrocardiogram in supporting the clinical diagnosis. In addition, however, sequential changes in both the maximum QRS and T vector orientations in frontal and transverse planes were more often apparent than any sequential changes in the 12-lead electrocardiogram. While no specific 3 lead electrocardiographic criterion for pulmonary embolism could be determined, this technique was more helpful than conventional methods in following serial electrocardiographic changes in patients with this condition.

Adult↗