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Biomedical subjects

W W Miller

Publications and source records attributed to W W Miller.

At least 19 recordsLinked to original sources
PubMed1990

Progress in the development of a fluorescent intravascular blood gas system in man.

In vitro and in vivo animal studies have shown accurate measurements of arterial blood pH (pHa), carbon dioxide tension (PaCO2), and oxygen tension (PaO2) with small intravascular fluorescent probes. Initial human clinical studies showed unexplained intermittent large drops in sensor oxygen tension (PiO2). Normal volunteers were studied to elucidate this problem. In the first part of this study, the probe and cannula were manipulated and the probe configuration and its position within the cannula were varied. The decreases in PiO2 were judged to be primarily due to the sensor touching the arterial wall. Retraction of the sensor tip within the cannula eliminated the problem. In the second part of this study, the accuracy of the retracted probe was evaluated in 4 subjects who breathed varying fractions of inspired oxygen and carbon dioxide. The arterial ranges achieved were 7.20 to 7.59 for pH, 22 to 70 mm Hg for PaCO2, and 46 to 633 mm Hg for PaO2. Linear regression of 48 paired sensor (i) versus arterial values showed pHi = 0.896 pHa + 0.773 (r = 0.98, SEE = 0.017); PiCO2 = 1.05 PaCO2 - 1.33 (r = 0.98, SEE = 2.4 mm Hg); and PiO2 = 1.09 PaO2 - 20.6 (r = 0.99, SEE = 21.2 mm Hg). Bias (defined as the mean differences between sensor and arterial values) and precision (SD of differences) were, respectively, -0.003 and 0.02 for pHi, 0.77 and 2.44 mm Hg for PiCO2, and -2.9 and 25.4 mm Hg for PiO2. The mean in vivo 90% response times for step changes in inspired gas were 2.64, 3.88, and 2.60 minutes, respectively, for pHi, PiCO2, and PiO2.

Blood Gas Monitoring, Transcutaneous↗
PubMed1990

Sensorineural hearing loss associated with Kawasaki disease.

In five children who met the diagnostic criteria for Kawasaki Disease, sensorineural hearing loss developed in association with the acute illness. The children, aged 7 months to 13 years, had deficits ranging from mild to profound bilateral sensorineural hearing loss. There were no associated neurologic abnormalities, and immunologic investigations and magnetic resonance imaging failed to reveal a cause. Treatment regimens differed among the children, but none had high salicylate levels (greater than 20 mg/dl) or received other ototoxic medications. Antiinflammatory therapy was not obviously beneficial in any case, and four of the children have persistent hearing deficits. We conclude that auditory involvement may be a complication of Kawasaki disease; screening of clinically affected children should be considered.

Adolescent↗
PubMed1989

Postnatal development of the photoreceptor inner segment of the retina in dogs.

In dogs, the retina develops during the postnatal period in a manner similar to that in other animals born with closed eyelids. Photoreceptor inner segments are initially observed as a cytoplasmic bulge protruding sclerad through the external limiting membrane. Outer segment formation begins when a centriole within the inner segment attaches to the distal inner segment cell membrane. A few round mitochondria are observed within the early inner segments. As maturation proceeds, the number of mitochondria within the inner segments increases and the mitochondria elongate, orienting parallel to the long axis of the inner segment.

Animals↗
PubMed1988

Granulomatous uveitis in an owl.

Granulomatous lens-induced uveitis was diagnosed in a mature male barred owl. Initial ocular examination revealed a large white mass in the left eye. Differential diagnoses for the mass included intraocular granuloma, neoplasia, foreign body, bacterial or fungal enophthalmitis, and fibrotic hematoma. After enucleation of the left globe, histologic examination revealed the mass to be a granulomatous inflammatory reaction to a posteriorly luxated, traumatized lens. Lens-induced uveitis should be considered whenever a bird has suffered lenticular trauma.

Animals↗
PubMed1988

Acid alpha-neuraminidase deficiency: a nephropathic phenotype?

Isolated neuraminidase deficiency is a member of the relatively rare group of storage disorders known as glycoproteinoses. We report the long-term natural history of the disease in one of the first patients described in the literature. An unusual feature of the disease is the abrupt onset and fulminant nature of the nephrotic syndrome, complications of which caused the demise of our patient. Pathological examination of the kidneys from this child revealed renal epithelial cell damage, most marked in the membranes of the glomeruli and proximal tubules, findings which are consistent with the high sialic acid content of the membrane in these areas of the nephron. Chemical analysis indicated that the bulk of the stored material in the kidney was in the form of polar sialyloligosaccharides of high molecular weight. On the basis of our experience, as well as the previous reports of neuraminidase-deficient patients with nephropathy, we propose a nephropathic phenotypic variant of type 2 infantile sialidosis.

Brain↗
PubMed1987

Performance of an in-vivo, continuous blood-gas monitor with disposable probe.

A fluorescence-based fiber optic measurement system has been developed for monitoring pH, pCO2, and pO2 through a 20-gauge radial artery catheter without compromising capabilities for monitoring arterial pressure or for blood withdrawal. The measuring probe consists of three optical fibers to which the sensing chemistries are attached, and a thermocouple that measures temperature. The probe is designed to meet in-vivo biocompatibility requirements for a one-time use of up to 72 h. The components that are in contact with the patient's blood are nontoxic, nonhemolytic, nonthrombogenic, and sterilizable. Blood compatibility is enhanced by including covalently bound heparin. The in-vitro accuracy of the system has been tested against commercial blood-gas measurement instruments; comparison with tonometry and blood gas values gave r greater than or equal to 0.98 for all three sensors. The standard error for all sensors was within the College of American Pathologists' accuracy guidelines for measuring blood gas. Instrumental drift was minimal, indicating that system performance characteristics should not be the limiting factor in obtaining clinically useful information for up to 72 h. The response times of the sensors in animal and in-vitro studies were less than 2 min, suitable for monitoring physiological changes in blood gas values.

Animals↗
PubMed1985

B-scan ultrasonography for the detection of space-occupying ocular masses.

A noninvasive technique, B-scan ultrasonography, was used to obtain detailed cross-sectional images of ocular and orbital structure and form. When a low-frequency probe (5 MHz) was used, tissue penetration was excellent; however, axial resolution was limited. The technique was used in a study of 2 cats and 1 dog. The use of low-frequency B-scan ultrasound should aid in the diagnostic examinations of space-occupying masses in the posterior portion of the ocular bulb and the orbit.

Abscess↗
PubMed1985

Effect of diet upon ventilation and effort perception during a physical stressor.

The present research explored the effects of a high and low carbohydrate diet on ratings of perceived exertion (RPE) during a 10 minute bicycle ergometer test at high physical work capacity (70% of maximum aerobic capacity). Twelve female student volunteers participated and were randomly assigned the order of diet treatments in which they served as their own control and/or experimental group. Following each dietary regimen, subjects were instructed to pedal the bicycle ergometer for ten minutes at an intensity of 70% of their maximum capability. Throughout the cycling protocol, RPE scores were recorded at 2, 4, 6, 8, and 10 minutes; in addition expiratory gases were collected and analyzed by a computerized indirect calorimetry system. Results in the current investigation indicated that an increased carbohydrate intake resulted in an "ergogenic" or "work-producing" effect by attenuating the metabolic acidosis, possibly diminishing the sensations of the central cardiopulmonary effort, further attenuating the psychophysiological perceptions of effort. Conversely, ingestion of a low carbohydrate diet resulted in accentuation of the ventilatory drive eliciting higher signals of exertion during dynamic exercise.

Adolescent↗
PubMed1985

Maximal work capacity in prepubescent obese and nonobese females.

Measurements of cardiorespiratory function during an incremental treadmill test were compared in 15 obese (OB) prepubescent girls, 7 to 12 years old, and in 15 age-matched, nonobese (NOB) controls. Open circuit calorimetry was used for data collection during the progressive work test. Maximal oxygen consumption indexed for weight was significantly lower in the obese group of girls (23.0 +/- 3.9 ml/kg/min) than in the nonobese controls (36.7 +/- 0.9 ml/kg/min). In addition, exercise tolerance was longer in the nonobese group, albeit not statistically significant. In conclusion, diminished cardiopulmonary performance and attenuated exercise tolerance in prepubescent obese females in the current investigation seemed to be influenced by excess body weight.

Body Height↗
PubMed1985

Preventive cardiology for coronary artery disease.

Primary and secondary risk factors and prevention strategies for coronary artery disease are reviewed. Cigarette smoking, hypertension, dyslipidemia, heredity, diabetes mellitus, obesity, beta blockades, and coronary artery bypass surgery are some of the topics discussed.

Cholestyramine Resin↗
PubMed1985

Familial cardiovascular risk factors: diagnosis and management in the young.

Risk factors for the development and progression of coronary atherosclerosis, hypertension, and cerebrovascular diseases are found in more than 10 per cent of children and adolescents in the United States. This article presents the criteria for the diagnosis of three of these risk conditions--dyslipidemia, hypertension, and obesity--and it reviews principles and specifics of their management in young people.

Adolescent↗
PubMed1984

Adaptation to maximal effort: genetics vs. environment. A case history.

An individual's functional ability in physiological responsiveness is thought to be an interaction between his heredity and his environment. This hypothesis was tested to determine if different extragenetic influences would alter functional adaptability in a set of MZ triplets. After a 3-month aerobic physical fitness training program varying only in frequency measured values for the triplets' maximum oxygen consumption (MaxVo2) were 59.1, 44.5, and 57.8 ml/min/kg, as compared to pretreatment values of 45.2, 45.1, and 49.1 ml/min/kg respectively. These results clearly indicate intrapair differences in functional adaptability, stemming from difference in the training frequency program. The split-triplet design of this study indicates that environmental factors contribute substantially to the intrapair variance found among MZ siblings. Data extrapolation suggests that environmental stimulation of sufficient magnitude is likely to alter the functional adaptability in the individual set by his genotype.

Adaptation, Physiological↗
PubMed1984

Personality and self-motivation during biochemical fatigue.

The present study was conducted to determine whether females exhibiting the Type A behavior pattern would exert greater effort and work to higher levels of physiological fatigue in a self-motivated ergometer test. Twenty female subjects, half of them Type A and the other half Type B, were administered an incremental ergometer test to determine their peak oxygen consumption value. On the first experimental session no experimenter encouragement was given to the subjects. Consequently the test measured physical motivation levels. During a second laboratory session, each subject was continuously encouraged by the experimenter to maintain exercising until she was truly incapable of further work. The highest rate of oxygen extraction during this latter session was considered the subject's maximum oxygen consumption (i.e., VO2 max). Type A and B subjects were compared in the nonmotivated testing session (experimental session 1) to their "true" individual capacities (maximum oxygen consumption demonstrated in experimental session 2). ANOVAs indicated no significant differences in self-initiated competitive behavior during a physical stressor.

Adult↗