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Biomedical subjects

R D Ross

Publications and source records attributed to R D Ross.

51 records · Page 3Linked to original sources
PubMed1986

Gas-liquid chromatography of 3-chloropropanediol.

To improve the gas chromatographic properties of 3-chloropropanediol, a phenylboronic acid derivative was prepared. This method appears to be suitable for trace analysis of the title compound. Epichlorohydrin, 1,2-propanediol, and 1,2-dichloropropanol were among the structurally related compounds shown not to interfere. The structure of the derivative was confirmed by gas chromatography-Fourier transform infrared spectroscopy utilizing a matrix isolation interface and gas chromatography-mass spectrometry.

Chlorohydrins↗
PubMed1984

Effects of source and particle size on the biological availability of calcium in calcium supplements for growing pigs.

Five experiments were conducted to determine the biological availability of the Ca in high-Ca (calcitic) limestone, dolomitic limestone, oyster shell flour, gypsum, marble dust and aragonite for the growing pig, and to determine the influence of particle size of the Ca source on the bioavailability of Ca. A low-Ca, fortified, corn soybean meal basal diet calculated to contain .2% Ca and .6% P was used. This diet was supplemented with 0 or .3% Ca from either CaCO3 precipitate (the standard) or the test source of Ca. Diets were fed on an ad libitum basis to three to eight replicate pens of pigs (one or two/pen) for 35 to 42 d. Average initial weight of the pigs was 15 kg. At the end of each experiment the pigs were killed, the third and fourth metacarpals and metatarsals and the femurs were removed, and breaking strength and ash were determined. The increase in bone strength from feeding the test source of Ca relative to the increase in bone strength from feeding the CaCO3 standard was used to calculate the relative availability of Ca in the supplements. The bioavailability of Ca in calcitic limestone (two sources), oyster shell flour, gypsum, marble dust and aragonite was similar, ranging from 93 to 102%. However, the Ca in two sources of dolomitic limestone was less available (51 and 78%) than in the other sources. Particle size of the Ca sources (geometric mean diameter of .10 to .54 mm) did not influence the availability of Ca.

Animals↗
PubMed1983

Behavior of cancer patients: a randomized study of the effects of education and peer support groups.

Two prospective, controlled studies were conducted to determine if psychological and social functioning could be enhanced in patients with Hodgkin's disease by either education or participation in a peer support therapy group. Eighty-one patients were evaluated with the Cancer Patient Behavior Scale prior to and following intervention. Following education, patients experienced significant improvement in the frequency of Anxiety, Treatment Problems, Depression, and Life Disruption (p less than or equal to 0.1) compared to a control group. Following participation in peer support groups, patients showed no improvement in any of 10 areas of life functioning. Thus education represents an effective, efficient, and inexpensive means of improving psychological and social behavior in patients with Hodgkin's disease. Participation in this peer support therapy group did not result in significant behavior change.

Adult↗
PubMed1981

Ultrasonographic parameters in the prenatal diagnosis of Meckel syndrome.

The ability to make a prenatal diagnosis of Meckel syndrome (encephalocele, polydactyly, and polycystic kidney) by ultrasound is described. Three cases are detailed; in 2 of these the diagnosis was made at 18 and 36 weeks' gestation, respectively. In case 1 Meckel syndrome was identified by the presence of oligohydramnios, microcephaly, and enlarged cerebral ventricles. In case 2 oligohydramnios was associated with an encephalocele, bilateral renal enlargement, and a polydactyly. In case 3 the diagnosis was excluded in a fetus at risk. The usefulness of ultrasound in making this diagnosis is discussed for cases in which the amniotic fluid alpha-fetoprotein value is normal, inconclusive, or unobtainable.

Abnormalities, Multiple↗
PubMed1980

Ultrasound criteria for in utero diagnosis of microcephaly.

Microcephaly (small head) is clinically important only if there is concomitant micrencephaly (small brain). Extensive studies on patients in mental institutions have shown that there is close correlation among microcephaly, micrencephaly, and mental retardation when the head is more than three standard deviations below the norm. If the small head is less than two standard deviations below the norm, no strong correlation exists with eigher small brain or mental retardation. High-resolution ultrasound permits imaging of the fetal head in utero, allowing accurate evaluation of head size and detection of intracranial anomalies. The microcephalics detected in utero over a 2-year period form the basis of this series, showing close correlation with the known clinical data on children with microcephaly. An approach to ultrasound detection and evaluation of fetal microcephaly is proposed.

Female↗
PubMed1978

Comprehensive analytical procedures for the determination of volatile and non-volatile, polar and non-polar N-nitroso compounds.

The first comprehensive analytical procedures for the quantitative analysis of N-nitroso compounds are described. The scheme divides N-nitroso compounds into four major, overlapping categories: volatile (Class I), non-volatile, low polarity (Class II), non-volatile, non-ionic, high polarity (Class III) and non-volatile, ionic, high polarity (Class IV). Existing analytical techniques for each class of compound are integrated into an organized and logical sequence of analysis to allow all classes of compounds to be determined. TEA-GC is used for the volatile compounds and TEA-HPLC for the non-volatile. It is emphasized that the coincidence of retention time in either TEA-GC alone or TEA-HPLC alone cannot be taken as sufficient evidence for the identification of N-nitroso compounds, especially for samples from complex matrices. Independent techniques are required to confirm these results. The confirmatory techniques used frequently in our laboratory are: (1) spectroscopic analysis (IR, NMR, UV and MS), (2) formation and identification of derivatives, and (3) parallel TEA-GC/TEA-HPLC techniques. These procedures are now used at Thermo Electron for the comprehensive screening of environmental samples.

Chemical Phenomena↗
PubMedDate not supplied

Atrial natriuretic factor and sympathetic nervous output in response to volume shifts in the immature canine circulation.

This study evaluated the immature circulation's response to acute shifts in intravascular volume with respect to atrial natriuretic factor and plasma catecholamines. Serial measurements were performed on thirteen beagle puppies during volume expansion with a saline and albumin solution followed by volume contraction with furosemide. Atrial natriuretic factor correlated with right (r = .73, p less than 0.001) and left (r = .62, p less than 0.001) atrial pressures and increased to much greater levels than previously reported for mature animals. Simultaneously, 10 puppies had a progressive decrease in plasma norepinephrine over the 60-minute infusion (p less than 0.05) while two puppies demonstrated a marked increase between the 30- and 60-minute samples. Furosemide increased urine output and reversed the hormonal changes caused by volume expansion. Thus a greatly augmented output of atrial natriuretic factor occurs in the immature canine circulation in response to increased atrial and pulmonary pressures, while sympathetic output remains unchanged or falls with increasing intravascular volume until a critical decrease in cardiac output triggers a catecholamine surge.

Aging↗
PubMedDate not supplied

Effectiveness of low dose captopril versus propranolol therapy in infants with severe congestive failure due to left-to-right shunts.

UNLABELLED: To evaluate the therapeutical effects of the angiotensin converting enzyme inhibitor Captopril to the beta-blocker Propranolol in infants with congestive failure due to pulmonary overcirculation, we retrospectively analysed clinical, neurohormonal and hemodynamic data in 22 infants, 11 of whom were treated with Captopril (Group 1), 11 with Propranolol (Group 2). Age, weight, number of palliative operations, plasma renin activities and pulmonary to systemic flow ratios (3.5 vs. 3.5) were not significantly different prior to Captopril or Propranolol therapy. If treatment with digoxin and diuretics did not succeed, the infants were additionally treated with Captopril (1 mg/kg) for a mean of 7.4 months, or with 1.9 mg/kg Propranolol for 9.2 months. RESULTS: 1 mg/kg Captopril did not effectively suppress angiotensin converting enzyme in the steady state at trough level (92+/-52 vs. 87+/-50 nmol/min/ml). In the Propranolol group, the clinical heart failure score (2.6+/-1.5 vs. 7. 4+/-2.5) and plasma renin activities (14+/-10 vs. 101+/-70 ng/ml/h) were significantly lower, compared to the Captopril group. Length of hospital stay (23+/-9 vs. 52+/-24 days) was lower and weight gain (126+/-38 vs. 86+/-84 g/week) was higher within 3 months after starting Propranolol therapy. Significantly lower left atrial pressures (6.2+/-2.2 vs. 13.4+/-9.2 mmHg) and lower endiastolic ventricular pressures (7.6+/-2.5 vs. 12.6+/-4.0 mmHg) during pre-operative cardiac catheterization indicated a better diastolic ventricular function under chronic Propranolol treatment. CONCLUSION: Although high dose Captopril was not evaluated in this study, when compared to patients on low Captopril dosages, infants who received Propranolol treatment showed improvement in heart failure scores, shorter lengths of hospital stay, lower plasma renin activities and better diastolic ventricular functions.

Angiotensin-Converting Enzyme Inhibitors↗