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Biomedical subjects

J Andrews

Publications and source records attributed to J Andrews.

At least 271 records · Page 15Linked to original sources
PubMed1983

Localization of human colorectal tumor xenografts in the nude mouse with the use of radiolabeled monoclonal antibody.

For the evaluation of the clinical usefulness of monoclonal antibodies as diagnostic or therapeutic reagents, tumor localization must be clearly demonstrated in an experimental model. In this report, nude mice carrying two human tumor xenografts--a colon carcinoma (Colo 205) and a melanoma (Colo 239)--were given ip injections of radiolabeled monoclonal antibodies. Monoclonal antibody 250-30.6, which reacted specifically with the colon carcinoma but not with the melanoma, was labeled with 125I, while a second monoclonal antibody of similar immunoglobulin subclass, but unreactive with either cell type, was labeled with 131I. Both antibodies were injected simultaneously, and either the mice were scanned with a gamma camera or their tissues were removed and the localization of radiolabeled antibody was calculated with the use of localization index (LI)--the ratio of the tissue to blood distribution for each isotope. The studies showed that specific localization had occurred, there being a colon tumor LI of 6 at 2 days. Tumors of 150-300 mg (mean diameter, 6 mm) and with an LI as low as 1.5 could be successfully imaged after computer-assisted background subtraction. This study demonstrated that relatively small human tumor xenografts in the nude mouse can be specifically detected with the use of paired monoclonal antibodies, each labeled with a different isotope.

Animals↗
PubMed1982

Biochemical characterization of canavalin, the major storage protein of jack bean.

The structure of canavalin, a jack bean (Canavalis ensiformis) protein homologous to phaseolin, the major seed storage protein of Phaseolus vulgaris, has been investigated by x-ray crystallography and found to be a hexamer composed of three identical pairs of similar but nonidentical subunits related by a perfect 3-fold axis and pseudo dyad axes (strict C(3) and pseudo D(3)). One member of each pair of subunits is derived from the amino terminal half of a precursor polypeptide of molecular weight 49,000 and the other from its carboxy terminal half. Thus, the crystallographic evidence indicates that the precursor polypeptide is a tandem duplicate and is structurally redundant (McPherson A. 1982 J Biol Chem 255: 10472). A number of physical and chemical properties of the protein in both the uncleaved and the cleaved form were investigated. These included the native molecular weights, amino acid analyses, number of exposed sulfhydryl groups, carbohydrate content, metal ion analysis, crystallization behavior, and the fate of the protein in developing seeds. It was also found that the purified precursor protein possesses a substantial level of alpha-d-mannosidase activity and seems to share a number of other physical and chemical properties with that enzyme.

Journal Article↗
PubMed1982

Diuretic radionuclide renography in upper urinary tract obstruction.

Diuretic renography using radioidine sodium hippurate and a frusemide stimulus was used to differentiate between obstructive and nonobstructive dilatation of the urinary tract. Information was recorded by a gamma camera on line to a computer. Sixty-seven uretero-renal units (URU) were studied in 33 patients with an average age of 91/2 years. The diuretic renogram correctly indicated obstructions in 18 URU but gave false positive results in another five. Of these five, four had severely impaired function. The renogram indicated nonobstruction in 49 URU, and gave false negative results in another two; of these two one patient had a duplex kidney with a poorly functioning ureteric segment and the other patient had gross reflux and megaureters. The diuretic renogram is useful in the investigation of equivocal upper urinary tract obstruction but may be unreliable in situations of inadequate renal function.

Adolescent↗
PubMed1982

Non-steroidal anti-inflammatory drugs and blood pressure.

The effects of aspirin (1950 mg/day orally) or indomethacin (75 mg/day orally) on blood pressure were investigated in normotensive volunteers and hypertensive patients receiving antihypertensive medication. Aspirin (1950 mg/day) did not change blood pressure or body weight in normotensive or treated hypertensive subjects. No significant change in plasma renin concentration was seen with aspirin (1950 mg/day) in treated hypertensive subjects. Indomethacin (75 mg/day) significantly increased blood pressure in normotensive subjects and treated hypertensive subjects. Body weight increased significantly in the treated hypertensive subjects but not normotensive subjects. In treated hypertensive subjects indomethacin (75 mg/day) did not change plasma volume, but significantly decreased plasma renin concentration.

Adolescent↗
PubMed1981

Rewarding effects of hypothalamic self-stimulation altered by unilateral lesions of superior colliculus in rats.

The effects of unilateral lesions of the superior colliculus were determined on self-stimulation of the medial forebrain bundle. It was found that the lesions had different effects depending upon the precise location of the stimulating electrode: self-stimulation on far-laterally located electrodes was abolished while on more medially placed electrodes this behaviour was enhanced. These data are inconsistent with explanations of intracranial self-stimulation which treat it as a unitary phenomenon.

Animals↗
PubMed1981

Separation and characterization of inner and outer envelope membranes of pea chloroplasts.

A procedure for purifying the chloroplast envelope subfractionates it into two membrane fractions of comparable quantities. This procedure differs from previous ones in that the chloroplasts are ruptured by freezing and thawing in hypertonic medium rather than by osmotic shock. The two membrane fractions have qualitatively similar polar lipid compositions but differ in their content of individual lipids, specifically monogalactosyldiacylglycerol and phosphatidylcholine. The two fractions also differ in their constituent polypeptides and in their appearance when examined by electron microscopy. The light (density = 1.08 g/ml) and heavy (density = 1.13 g/ml) membrane fractions have been tentatively identified as the outer and inner envelope membranes, respectively.

Journal Article↗
PubMed1981

Franco-British disparities in medicine.

A questionnaire in French and English was sent to physicians practising geriatric medicine in France and the UK concerning certain aspects of their clinical practice. It also enquired of the doctors their place of practice, year of qualification, present position held, and in which part of the respective country they worked. Most of the answers reflect major divergencies in methods of clinical practice between the two countries. These answers are reported, highlighted, commented on, and speculation made of the possible reasons for the differences. We feel that international questionnaires are a useful way of alerting doctors to areas of practice which are falsely assumed to be correct; they may also reveal the possible basic solutions to common clinical problems.

Attitude of Health Personnel↗
PubMed1980

Oral contraception and congenital abnormalities.

Of 10 479 single births in South Glamorgan between January 1974 and June 1976, 27.3 per cent of infants were born to women who had used oral contraception in the three months prior to their last menstrual period (users) and 72.3 per cent were born to women who had not used oral contraception during the same period (non users). There were significantly more infants with neural tube defects among users compared with non users. Abnormalities of the digestive, genito-urinary and cardiovascular system, bones, muscle, skin and connective tissues, endocrine glands, blood chromosomes and oral clefts, were of similar incidence in the two groups.

Abnormalities, Drug-Induced↗