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Biomedical subjects

R Guthrie

Publications and source records attributed to R Guthrie.

At least 55 records · Page 3Linked to original sources
PubMed1988

The incidence of Legionella pneumophila as the cause of acute ambulatory lower respiratory tract infection.

Seventy-nine ambulatory patients with acute lower respiratory tract infection were evaluated for Legionella pneumophila by acute and convalescent antibody titers. None of the patients met the traditional criteria for the diagnosis of acute infection caused by Legionella pneumophila. Currently accepted criteria for diagnosing legionellosis by serologic means may or may not be applicable to mild respiratory tract infections.

Ambulatory Care Facilities↗
PubMed1987

A fluorometric micromethod for estimation of carnosinase in dried blood samples.

We describe a microfluorometric method for determination of carnosinase activity in dried blood spots on filter paper. The carnosinase in discs punched from such dried blood specimens is activated with cadmium at 30 degrees C. After incubation with the substrate carnosine at the same temperature, histidine is determined fluorometrically. We compare the results of this method with those of a fluorometric method using liquid blood and assess the stability of the enzyme in dried blood on filter paper. The presence of erythrocytes has no effect on the activity. The method may be useful in early detection of carnosinase deficiency and certain other metabolic disorders.

Adult↗
PubMed1987

Quantitative determination of porphyrins, their precursors and zinc protoporphyrin in whole blood and dried blood by high-performance liquid chromatography with fluorimetric detection.

Methods for the determination of porphyrins, delta-aminolevulinic acid (ALA), porphobilinogen (PBG) and zinc protoporphyrin of heme biosynthesis in whole blood and dried blood are described. Erythrocyte porphyrins and the precursors ALA and PBG were extracted from whole blood (50 microliter) with 0.3 ml of methanol and 1.5 M hydrochloric acid (2:1, v/v). Zinc protoporphyrin was extracted with an acetone-pyridine-Sterox solution. Other major interfering metabolites were removed by centrifugation. An aliquot of the supernatant was injected onto the reversed-phase C18 column for detection of porphyrins with excitation wavelength at 405 nm and emission wavelength at 630 nm. The mobile phase was 0.1 M phosphate-methanol-tetrahydrofuran (18:30:16, v/v/v), pH 5.38. The ALA and PBG were derivatized with o-phthalaldehyde before injection. The detection excitation wavelength occurred at 330 nm and the emission wavelength at 418 nm. The mobile phase was 0.1 M phosphate-methanol (7.5:5), pH 3.38. For the dried blood specimen of filter paper, two 0.64-cm discs punched out from the blood-impregnated filter paper were placed in a test tube containing 200 microliter of 0.9% saline for 60 min or longer at room temperature and then treated as whole blood.

Chromatography, High Pressure Liquid↗
PubMed1987

An evaluation of a new test kit to screen for galactosemia.

A new galactosemia screening kit has been evaluated. The kit employs the Yoshida modification of the Paigen et al. Escherichia coli bacteriophage assay and is produced by Eiken Co. Ltd. of Japan. The assay estimates galactose and galactose-1-phosphate in dried blood specimens. The kit is sufficiently sensitive to detect possible heterozygotes as well as possible homozygotes.

Biological Assay↗
PubMed1987

Biomedical prevention of mental retardation. A model state plan.

A model state plan for prevention coordinates human, economic, and social resources in a thoughtful process of identification of causes and prevention of mental retardation and a systematic application of that knowledge through a variety of approaches. Systems approaches suggest that "everything is connected to everything else." In this connection, a program, by definition, should be a planned effort to approach various aspects of an identified major problem by means of a series of interrelated projects; a single, isolated, one-shot project is not a program. This definition of program connotes a sustained commitment consistent with planned social change in order to modify institutions to make them more responsive to community need (Goldston, 1977). A sustained commitment is the cornerstone of a model state plan for prevention. The meshing of effort and services demanded of comprehensive prevention planning requires the support of both the executive and legislative branches of government.

Child↗
PubMed1986

Detection of delta-aminolevulinic acid, porphobilinogen and porphyrins related to heme biosynthesis by high-performance liquid chromatography.

Two new high-performance liquid chromatographic methods are described for the quantitative determination of porphyrins and their precursors. In our method, sub-nanomole quantities of porphyrins, delta-aminolevulinic acid and porphobilinogen derivatized with ophthalaldehyde were injected onto a C18 reversed-phase column and eluted with 0.1 M monobasic sodium phosphate-methanol-tetrahydrofuran (4:6:3) and detected with a spectrofluorometer. A second reversed-phase system using methanol-tetrahydrofuran-22 mM acetate buffer (15:6:11) was also developed.

Aminolevulinic Acid↗
PubMed1986

Microassay for estimation of galactose and galactose-1-phosphate in dried blood specimens.

A fluorometric assay for blood galactose and galactose-1-phosphate has been modified and improved to shorten the analysis time and to increase sensitivity above other published methods. The method may be useful as a quantitative screening or routine clinical test to detect infants suspected of having a defect of galactose metabolism. It can also be used to monitor blood galactose or galactose-1-phosphate levels in children with galactosemia who are on a lactose-free diet.

Alkaline Phosphatase↗
PubMed1986

The effects of glucagon and metoclopramide as measured by the electrogastrogram.

The electrogastrogram, purportedly a measurement of the stomach's electrical activity, has received increased attention recently. This attention has also created skepticism because measurements are taken from the cutaneous surface. To test the electrogastrogram's ability to measure the stomach's electrical potential, we infused glucagon (0.5 mg), metoclopramide (10 and 20 mg in two sittings), and a placebo into six subjects. The electrogastrogram registered predictable changes in response to these infusions. We conclude that the electrogastrogram measures the stomach's electrical activity. Additionally, the unique data gathered by the electrogastrogram suggest that glucagon and metoclopramide both act directly on the electrical activity of gastric cells.

Double-Blind Method↗
PubMed1985

High incidence of lead poisoning revealed by erythrocyte protoporphyrin (EPP) screening in Arabian children.

The measurement of erythrocyte protoporphyrin (EPP) has been used in screening infants for undue exposure to lead. The infants were from a high risk area, Al Jahra in Kuwait, and were selected from those attending the emergency department of Al Jahra District Hospital. Dried spots of blood on Guthrie filter paper were mailed to the Central Laboratory of the Children's Hospital in Buffalo, New York. Elevated EPP values (greater than 50 micrograms/dl) were present in 63 (66%) out of 96 tests. Forty-four of the infants with elevated values were investigated further: 16 had blood lead levels above 30 micrograms/dl (1.45 mmol/l) and 12 had evidence of iron deficiency anaemia. Five infants with blood lead levels above 80 micrograms/dl (3.9 mmol/l) needed urgent chelation and in addition an 8-month-old infant with the highest EPP value (478 micrograms/dl) died of acute lead encephalopathy. We conclude that lead poisoning is a serious problem in Al Jahra, Kuwait, and that a comprehensive programme for screening and health education are urgently needed to avoid the irreversible effects of lead toxicity.

Child, Preschool↗
PubMed1985

Degradation of rat brain cholinergic muscarinic receptors in vitro: enhancement by agonists and inhibition by antagonists.

Cholinergic muscarinic receptors undergo proteolytic degradation in vitro under physiological conditions as shown by a loss in [3H]quinuclidinylbenzilate binding activity. The serine protease inhibitor phenylmethylsulfonyl fluoride was very effective in diminishing the receptor loss. Soybean trypsin inhibitor was less effective. Both EDTA and EGTA were also effective in abolishing receptor degradation, suggesting the involvement of metallopeptidases in the process. Calcium-dependent neutral proteases requiring sulfhydryl reducing agents did not seem to be involved in receptor degradation. Dithiothreitol failed to enhance receptor degradation and iodoacetamide, leupeptin, and antipain, inhibitors of this enzyme class, failed to alter receptor loss as measured by radioligand binding. Most of the proteolytic activity occurred in the cytosol and was readily resolved from the receptor in the membrane fraction. We found that [3H]quinuclidinylbenzilate, an antagonist, inhibited the rate of receptor loss. On the other hand, agonists (acetylcholine, methacholine, and muscarine) appeared to enhance the rate of receptor loss. We postulate that these opposite effects are due to differences in receptor conformation in response to ligand binding. Susceptibility to proteolysis may therefore serve as a probe for receptor conformation.

Acetylcholine↗
PubMed1985

Simplified procedure for producing Bacillus subtilis spores for the Guthrie phenylketonuria and other microbiological screening tests.

Bacillus subtilis ATCC 6051 and ATCC 6633 spores used in bacterial inhibition screening assays for genetic metabolism defects in newborn infants were produced by using liquid synthetic replacement sporulation media. These media allowed a high degree of sporulation, as judged by direct cell counts. Sporulation took place within 23 to 27 h with these media. Also, a more rational procedure for selecting the most sensitive clones of these organisms to the various inhibitors used in the microbiological screening assays is presented.

Bacillus subtilis↗
PubMed1982

Neonatal urine screening for metabolic disease with auxotrophic strains of Bacillus subtilis.

A simplified method for neonatal urine screening for metabolic diseases is described. This procedure involves the use of two bacterial inhibition assays which can detect uracil, lysine, and homocystine, in combination with two other assays utilizing spores of amino acid auxotrophic mutants of Bacillus subtilis which can detect several amino acids and purines. These four tests have the capability to detect several treatable inherited metabolic diseases, including three disorders of the urea cycle, using a urine specimen on filter paper. This method results in savings of cost and time over chromatographic screening procedures, since only four agar trays (56 specimens per tray) are used, which can be processed with one cycle through a semi-automated punch index machine.

Bacillus subtilis↗
PubMed1982

Screening test for alpha 1-antitrypsin in dried-blood specimens.

We describe a fluorescent spot test for detecting alpha 1-antitrypsin activity in dried-blood specimens. The eluate of a blood disc is mixed with carbobenzoxy-L-arginine-7-amino-4-methylcoumarin amide and trypsin at the appropriate pH. In the absence of alpha 1-antitrypsin, aminomethylcoumarin, a strongly fluorescent compound, is released. The reaction mixture, when spotted on chromatography paper and viewed under ultraviolet light, exhibits a bright fluorescence only in the case of specimens with alpha 1-antitrypsin deficiency. alpha 1-Antitrypsin activity so estimated correlated well with quantitative assays of dried-blood spots and serum. The procedure is simple and inexpensive, and has the potential for use as a screening test.

Adult↗
PubMed1982

Laboratory confirmation of phenylketonuria. Combined paper chromatography and "inhibition assay".

It is absolutely necessary to confirm any positive screening result for phenylketonuria by two or more independent procedures carried out on two or more different blood specimens before initiation of diet treatment. Details for a combined paper chromatography and "inhibition assay" of cut paper strips for positive identification of blood phenylalanine are given. This procedure correlates the partition between two solvents, the reaction to ninhydrin and the reaction in "inhibition assay".

Chromatography, Paper↗