Sterility of disposable syringes.
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Disposable Equipment↗
Biomedical subjects
R M Ward
Publications and source records attributed to R M Ward.
Spatial and spatial-frequency primitives in spatial-interval discrimination.
Thresholds for spatial-interval discrimination were determined under conditions designed to introduce randomness in the spatial-frequency content of the stimuli from trial to trial. Neither a random scaling of the display nor the addition of flanking bars at varying distances affected the observer's ability to judge the relative interval between pairs of bars, provided that the flanking bars were clearly resolved from the targets. Performance deteriorated only if the flanking bars were too close (less than about 2 arc min) or if the display was optically blurred. We conclude that the results pose difficulties for spatial-frequency theories of interval discrimination.
Discrimination, Psychological↗
Evaluation of a QRS scoring system for estimating myocardial infarct size. IV. Correlation with quantitative anatomic findings for posterolateral infarcts.
This study correlated the location and size of posterolateral myocardial infarcts (MIs) measured anatomically with that estimated by quantitative criteria derived from the standard 12-lead ECG. Twenty patients were studied who had autopsy-proved, single, posterolateral MIs and no confounding factors of ventricular hypertrophy or bundle branch block in their ECG. Left ventricular anatomic MI size ranged from 1 to 46%. No patient had a greater than or equal to 0.04-second Q wave in any electrocardiographic lead and only 55% had a 0.03-second Q wave. A 29-point, simplified QRS scoring system consisting of 37 weighted criteria was applied to the ECG. Points were scored by the ECG in 85% of the patients (range 1 to 8 points). MI was indicated by a wide variety of QRS criteria; 19 of the 37 criteria from 8 different electrocardiographic leads were met. The correlation coefficient between MI size measured anatomically and that estimated by the QRS score was 0.72. Each point represented approximately 4% MI of the left ventricular wall.
Adult↗
Pharmacology of tolazoline.
Tolazoline's complex pharmacologic effects likely represent the algebraic sum of primary, secondary, and possibly tertiary interactions with histamine and adrenergic receptors. Oxygenation improves initially in the majority of neonates with PPHN treated with tolazoline. Preliminary studies of tolazoline pharmacokinetics in the newborn indicate current doses are excessive and lead to accumulation, which may contribute to adverse effects, including cardiotoxicity.
Adult↗
Tolazoline pharmacokinetics in lambs.
Tolazoline has often been administered experimentally to lambs without consideration of its pharmacokinetics. We have used a chemically specific assay to determine tolazoline pharmacokinetic parameters in lambs after pulse and infusion doses: alpha = 0.184 +/- 0.046 (min-1), beta = 0.010 (pulse) and 0.0098 (infusion) +/- 0.0010 (min-1), Vdarea = 2534 +/- 688 ml/kg (pulse), and Vdss = 2890 +/- 342 ml/kg (infusion). The following doses can be used to reach steady-state plasma tolazoline concentrations: loading dose (microgram/kg) = 2890 X desired concentration (microgram/ml); infusion rate (microgram/kg X min) = 2890 (.010) X desired concentration (microgram/ml). These doses were used to produce 68 steady-state concentrations from 0.25 to 10.0 micrograms/ml. Clearances at steady state averaged 166 ml/min or 27.1 ml/min X kg at 2-17 days but increased markedly by 4 weeks of age. Using these doses, tolazoline-receptor interactions can be studied at constant plasma concentrations that approximate constant receptor concentrations.
Animals↗
Disposition of dietary caffeine in milk, saliva, and plasma of lactating women.
Caffeine is present in many dietary substances; its appearance from these sources in human milk has not previously been studied in detail. Fifteen lactating women ingested a known amount of a caffeinated beverage (36 to 335 mg). Simultaneous milk and saliva samples were collected at intervals for the subsequent 12 hours and assayed for caffeine content. Eleven of 15 mothers excreted measurable caffeine in milk. Caffeine was detected by 15 minutes in saliva and milk; peak levels in milk (2.09 to 7.17 micrograms/mL) and saliva (1.24 to 9.22 micrograms/mL) were achieved within 1 hour. Elimination half-lives were 1.3 to 13.5 hours (mean 4.0 +/- 3.7 [SD] hours) for saliva and 1.5 to 14.5 hours (mean 6.1 +/- 4.4 [SD] hours) for milk. Assuming each infant would ingest 90 mL of milk every three hours for 24 hours after maternal ingestion of caffeine, it is possible to estimate potential exposure of the nursing infant to caffeine. The amount of caffeine available for infant absorption ranged from 0.01 to 1.64 mg or 0.06% to 1.5% of the maternal dose. Caffeine was not present in the infants' urine collected for five hours after the first nursing period. The maternal ingestion of a single cup of caffeinated beverage does not appear to present significant doses of caffeine to the nursing infant.
Adult↗
The use of different cues in vernier acuity.
The roles of the various cues in the traditional vernier target are examined. We conclude that there are at least two mechanisms by which vernier acuities of the order of 5 sec arc may be obtained. The two cues are the overall slope of the target, and the relative positional differences. By using vernier targets that are degraded in two different ways, we can demonstrate each mechanism.
Humans↗
Identical genetic profiles in primary and metastatic bladder tumors.
Transitional cell carcinoma of the bladder has been shown repeatedly to possess abnormal genetic profiles. During long periods recurrent tumors in the bladder consistently show the same type of genetic profile with each recurrence. We report on a patient with metastatic bladder cancer who had similar genetic profiles of the primary lesion and thoracocentesis fluid from the metastatic site. The significance of these findings is discussed.
Aged↗
Stimulus features that determine the visual location of a bright bar.
A modification to the standard vernier target that has a detrimental effect on acuity is described. The addition of an extra bar alongside one of the test bars and directly underneath the other increases thresholds by an amount that is a monotonic function of its luminance. This allows for the hypothesis that the location of a bright bar is a function of some widespread description of the light distribution arising from such a bar on the retina, rather than some local feature of such a distribution. In particular, the data are not consistent with any simple notion of boundary extraction and support the conjecture that position of a bar is assigned to the mean or centroid of its light distribution.
Form Perception↗
Prognosis in carcinoma of the urinary bladder based upon tissue blood group abh and Thomsen-Friedenreich antigen status and karyotype of the initial tumor.
Several markers of initial bladder carcinomas described recently may be clinically significant predictors of biological behavior of future recurrences. Comparison of the marker systems and assessment of the value of using multiple markers have been difficult, because the various markers have been studied in different patients. In this study, we compared four markers [chromosome mode, marker chromosomes, and expression of the ABH "blood group" antigens and the Thomsen-Friedenreich antigen (using immunoperoxidase or lectin immunoperoxidase methods)] in 39 patients presenting initially with low-stage bladder carcinoma and followed 3 to 11 years or until deep muscle invasion occurred. Each of the markers was significantly related to subsequent recurrences with deep muscle invasion, and each marker system was able to identify those patients with a very low risk of subsequent invasion. For detection of a subpopulation of patients with Grade II carcinomas who were at high risk for development of subsequent invasion, combinations of markers, especially hyperdiploidy and abnormal expression of the Thomsen-Friedenreich antigen, were significantly more effective than any single marker system.
ABO Blood-Group System↗
Assessment of antifungal therapy in an 800-gram infant with candidal arthritis and osteomyelitis.
A 720-g premature newborn developed disseminated candidiasis during treatment with systemic antibiotics and total parenteral nutrition through an umbilical arterial catheter. Clinical features were typical for candidal skeletal infection at this age and included warmth and fusiform swelling of the lower extremities together with radiographic evidence of osteolysis and cortical bone erosion. Candida albicans was cultured from blood, urine, joint fluid, and a bone aspirate. The infection was cured with a 44-day course of amphotericin B and flucytosine (5-fluorocytosine). Antifungal therapy was monitored closely with serum drug levels and laboratory tests for bone marrow toxicity and renal dysfunction. Serum levels of both drugs were comparable to those achieved in older patients treated with similar doses. Significant concentrations of amphotericin B were detected in serum four and 17 days after completion of therapy, indicating a slow rate of elimination similar to that which occurs in adults. There was no evidence of drug-induced toxicity other than transient elevation in the fractional urinary excretion of sodium. This suggests that antifungal therapy may be effectively and safely administered to infants in dose schedules similar to those used for older patients.
Amphotericin B↗
Determination of tolazoline in plasma by gas chromatography-mass spectrometry.
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Gas Chromatography-Mass Spectrometry↗
Chorioamnionitis and possible neonatal infection associated with Lactobacillus species.
A patient is described with premature labor at 32 weeks of gestation complicated by chorioamnionitis associated with Lactobacillus species, subsequent premature delivery, and possible neonatal infection. Mother and infant did well with antibiotic therapy. The significance of chorioamnionitis and neonatal pneumonia due to this organism group is discussed.
Adult↗
Diagnosis of pleural effusions by chromosome analysis.
Cytogenetic changes, namely numerical (aneuploidy) and morphologic chromosome abnormalities including markers, clearly indicate the presence of malignant cells. To compare the utility of chromosome and cytogenetic analysis, the idiopathic pleural effusions of 60 patients were subjected to a double-blind analysis. A fluid was considered "positive" for malignancy if there was a marker chromosome, or if 10 percent of metaphases were hyperdiploid. Of the 33 neoplastic effusion, 30 (91 percent) were diagnosed "positive" by chromosome analysis whereas only 21 (64 percent) were classified "positive" or "suggestive positive" by cytology. All 27 benign effusions were correctly diagnosed by cytology; however, two were labelled "positive" by chromosome analysis. Combining the results of cytologic and chromosome analysis did not increase the number of "positive" diagnoses.
Chromosome Aberrations↗
The metabolic effects of caffeine in the newborn infant.
We studied the effects of intravenous administration of 20 mg/kg caffeine citrate on glucose homeostasis, cardiorespiratory status, and urinary excretion of catecholamines and electrolytes in 12 premature infants with recurrent apnea. Six infants received intravenous dextrose (5% or 10% in 0.225% saline) during the study, and six were fed formula every 3-4 hours. In the intravenously fed infants, the plasma glucose concentration postcaffeine did not vary significantly from the precaffeine level of 73 +/- 3.2 mg/dl (mean +/- SEM) at 0.5, 1, and 1.5 hours. However, in the formula-fed infants, there was a consistent fall in plasma glucose levels after caffeine administration. This decrease from a precaffeine level of 99 +/- 12 mg/dl (mean +/- SEM) approached statistical significance at 0.5 hours (P = 0.07), and was significantly lower at 1 and 1.5 hours (P less than 0.02). In five infants, cardiorespiratory status and urinary excretion of catecholamines and electrolytes were evaluated for 12-hour periods before and after caffeine administration. There was a significant reduction in the number of apneic episodes following caffeine administration; however, caffeine did not appear to affect mean heart rate or urinary excretion of sodium, potassium, epinephrine, norepinephrine, or dopamine. Our data suggest that the effects of caffeine on glucose homeostasis may vary with the nature and/or route of substrate administration.
Apnea↗
Metabolic effects of methylxanthines.
As predicted, methylxanthines influence several metabolic processes and increase the serum concentrations of glucose, FFAs, and catecholamines in adults. Although these increases are significant statistically, they may not be clinically important. Based upon a small number of studies, methylxanthines seem to affect infants in a more complex fashion. In infants, methylxanthines increase metabolic rate, do not increase catecholamine release, and produce variable effects on carbohydrate balance. The serum glucose concentration after methylxanthines likely represents a complex interplay of glycogen stores, types of nutrient administered, rate of nutrient administration, and degree of increased metabolic rate. Carefully controlled prospective studies are needed to determine the possible effects of methylxanthines on growth, carbohydrate balance, FFA release, and salt and water excretion at high and low serum concentrations. In addition, it is necessary to assess the effect on these variables of chronic pre- and postnatal exposure to methylxanthines.
Adult↗
Cytogenetics of bladder carcinoma: a key to prognosis in noninvasive and submucosal invasive carcinoma.
In 65 patients with noninvasive or submucosal invasive well-differentiated carcinoma of the bladder observed for 15 months to 11 years, cytogenetic analysis by the direct technique (nonculture) has been serially performed. Markers (abnormal chromosomes) have been found in 45 tumors, and recurrence has developed in all 45, resulting in 16 deaths. Two of the 20 patients without markers have developed recurrence. In one recurrence, 8 months postdiagnosis, the karyotypic mode changed from 69 to 92, evidence of development of a new tumor in a bladder prone to neoplasia. Based on our overall cytogenetic experience with 200 patients with carcinoma of the bladder a new classification is presented. This classification, builds on objective cytogenetic characteristics of early carcinoma, including the presence or absence of marker chromosomes, allows accurate prognosis, and thus provides the basis for development of standard therapy.
Chromosomes, Human↗
Prognosis in early carcinoma of the bladder based on chromosomal analysis.
In 53 cases of non-invasive or submucosal invasive well differentiated carcinoma of the bladder observed for 4 to 101 months cytogenetic analysis by the direct technique (non-culture) has been performed repeatedly. Markers, abnormal chromosomes, have been found in 33 patients and recurrence has developed in 32 of these 33 patients, resulting in 9 deaths. All but 1 of the 20 patients without markers have been observed for up to 8 years and have remained free of recurrence. In this 1 recurrence, 8 months post-diagnosis, the mode changed from 69 to 92, evidence of dedifferentiation and development of a new tumor in a bladder prone to neoplasia. Based on our over-all cytogenetic experience with 165 patients with carcinoma of the bladder a simplified classification is presented. This classification, built on measurable characteristics of early carcinoma, including the presence or absence of marker chromosomes, allows accurate prognostication and, thus, provides the foundation for development of standard therapy.
Adult↗