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Biomedical subjects

A Hill

Publications and source records attributed to A Hill.

At least 307 records · Page 17Linked to original sources
PubMed1977

Urinary p-tyramine in hereditary tyrosinemia: I. Levels as compared to normal individuals, effect of diet, and relationship to urinary tyrosine.

1. A 40-fold increase in urinary p-tyramine was observed in a patient with hereditary tyrosinemia as compared to a control population. 2. The excretion of urinary-free p-tyramine was decreased with the restriction of oral phenylalanine and tyrosine in this patient. The pattern of urinary tyrosine and urinary-free p-tyramine was similar during the period of normal protein diet and restricted diet of phenylalanin and tyrosine. 3. The pattern of urinary-free p-tyramine and tyrosine following oral loads of tyrosine and phenylalanine was similar except for a lag period before a tyramine response was observed. 4. The possibility of the patient with hereditary tyrosinemia providing a model to study the origin of urinary p-tyramine is discussed.

4-Hydroxyphenylpyruvate Dioxygenase↗
PubMed1977

Urinary p-tyramine in hereditary tyrosinemia: II. Origin of urinary p-tyramine.

1. A patient with hereditary tyrosinemia (tyrosinosis) was given oral loads of p-tyramine and tyrosine with and without medication (neomycin) to investigate the respective roles of intestinal bacteria and tissues in accounting for the origin of urinary p-tyramine. 2. The excretion of a high circulating level of p-tyramine following an oral load of p-tyramine in a patient with hereditary tyrosinemia (tyrosinosis) was as conjugated p-hydroxyphenylacetic acid (p-HPAA) and conjugated p-tyramine. 3. Both intestinal bacterial activity and tissue decarboxylation appeared to account for urinary p-tyramine in this patient following an oral load of tyrosine. 4. Sterilization of the gut by oral neomycin and a second load of oral tyrosine further supported a predominate role for tissue decarboxylation in the origin of urinary p-tyramine. 5. The data suggested that a major route of tyrosine metabolism in man may be via tissue decarboxylation of tyrosine.

4-Hydroxyphenylpyruvate Dioxygenase↗
PubMed1977

Urinary mandelic acid: identified in normal individuals following a single oral load of phenylethylamine.

1. An increased urinary mandelic acid was identified by gas-liquid chromatography in the urine of 3 healthy subjects following the oral ingestion of phenylethylamine. 2. The pathway for the formation of mandelic acid from phenylethylamine was suggested to involve the intermediate phenylethanolamine. The basic similarity of the metabolism of phenylethylamine and tyramine was suggested by the excretion of 4.5% of phenulethlamine as mandelic acid which correlated well to a reported 7.2% of p-tyramine excreted as p-hydroxy mandelic acid.

Humans↗
PubMed1977

Reproducibility of measurements of oestrogen-receptor concentration in breast cancer.

The reproducibility of measurements of oestrogen-receptor activity has been examined in multiple specimens from a rabbit uterus, a rat mammary tumour and human breast tumours. The relationship between receptor concentration and tumour histology has also been investigated in 11 large primary tumours. In the animal tissues, receptor measurements were relatively reproducible (coefficient of variance: wet wt. basis 16-17%, protein basis 16-21%) but in human breast tumours receptor activity varied considerably (c.v.: wet wt. basis, 22-125%; protein basis, 28-72%). In addition to these variations in receptor activity within tumours, there was a difference between tumours, as demonstrated by an analysis of variance (P less than 0.01). In the 11 primary breast cancers selected for study, the level of receptor activity was related to menopausal status and the tumour content of the specimen. We conclude that the receptor activity detected varies within a tumour and depends upon the tumour content of the biopsy specimen. Predictions based on precise quantitation of receptor concentrations may therefore necessitate replicate tumour sampling and correction for the fraction of non-tumour tissue in each sample.

Animals↗
PubMed1976

Difficulties and pitfalls in the interpretation of screening tests for the detection of inborn errors of metabolism.

A review of factors which may be responsible for false positive and false negative results in a screening program for the detection of inborn errors of metabolism is presented. Administration of medication, dietary therapy, chemical treatment of specimens, delay in analysis, hypersensitivity of procedures utilized, interfering metabolites and inadequate metabolic development or enzymatic maturation in the patient may all produce results resembling an actual inborn error of metabolism. Inadequate nutritional intake prior to procurement of specimen and loss of material during analytical procedures may produce false negative results. As well, certain less severe variants of inborn errors may present in an unusual manner or may only present during periods of stress to the patient. These factors are discussed in relation to the performance of a metabolic screening program. It is suggested that these progrms should be performed by specialized, central laboratories experienced in the complexities of detection of inborn errors of metabolism.

Anticonvulsants↗
PubMed1976

Monitoring of midmyocardial and subendocardial pH in normal and ischemic ventricles.

Midmyocardial and subendocardial pH monitoring was used as an indirect method for continuous evaluation of regional canine myocardial ischemia. Left ventricular midmyocardial pH (pHm) at 4 mm. depth was monitored in 10 dogs, under resting conditions, by means of a 5 mm. Beckman pH probe. pHm was 6.96 +/- 0.03, recorded at myocardial temperatures of 35 to 37 degrees C. Ischemia was then produced by snare occlusion of the proximal left main coronary artery for 2 minutes. pHm decreased to 6.87 +/- 0.03 (p less than 0.01) at 1 minute and 6.80 +/- 0.04 (p less than 0.005) in 2 minutes. When flow was restored, pHm returned toward normal within 2 minutes (pH 6.86 +/- 0.03) and at 5 minutes had returned to control values (pH 6.93 +/- 0.03). In another 5 dogs under similar conditions, pHm at 4 mm. and subendocardial pH (pHe at 8 mm.) were measured. Baseline pHm (6.97 +/- 0.01) and pHe (6.84 +/- 0.02) levels were significantly different (p less than 0.0005). After 2 minutes of ischemia, pHm was 6.82 +/- 0.03, whereas pHe decreased to 6.78 +/- 0.04 (p less than 0.1). Five minutes after snare release, pHe remained at 6.73 +/- 0.07; pHm (6.93 +/- 0.03) returned to control values. Both pHm (6.93 +/- 0.02) and pHe (6.84 +/- 0.09) levels were normal 15 minutes after release of the snare. The midmyocardium and subendocardium have different pH levels which can be monitored. Ischemia produces different pH patterns in these layers. pHm returns to control values within 5 minutes after 2 minutes of ischemia, whereas pHe remains depressed for at least 5 minutes. pH monitoring provides an accurate and simple method for on-line evaluation of endocardial ischemia.

Animals↗
PubMed1975

A simple method for the determination of oestrogen receptor concentrations in breast tumours and other tissues.

A simple method for the determination of oestrogen receptor activity in breast tumours and other tissues is described. By competition between radioactive and non-radioactive oestradiol-17beta for binding to a tissue extract prepared with centrifugation at low speed, the presence or absence of receptors is decided from the unmanipulated data. The concentration of receptors (P0) and dissociation constant of binding (Kd) are calculated by Scatchard analysis. In two relatively homogeneous tissues, assay precision was of the order of 16% for receptor concentration and 21-33% for the dissociation constant of binding: in heterogeneous breast tumors, much poorer precision can be expected. Sensitivity determined empirically is approximately 0.1 fmol/mg tissue. The method has been applied to the determination of receptor concentrations in human breast cancers, benign breast tumours, non-malignant breast, gynaecomastic breast, and in various tissues of the rat. Receptor activity was detected in 70% of the human breast cancers examined, and in lower amounts, in 21% of the benign human breast tissues. Activity was also detected in rat uterus and mammary gland, and in low amounts in 82% of the rat mammary tumours analysed. Dissociation constant of binding was generally of the order of 0.5 x 10(-10) M. The advantages of the method are discussed.

Adenocarcinoma↗
PubMed1975

Hypersensitivity alveolitis.

Hypersensitivity alveolitis developed in an 11-year-old girl during heavy exposure to mold spores contaminating the straw filters of an evaporation-type home air cooler. It is likely that the causative organism was Micropolyspora faeni, the mold responsible for farmer's lung.

Air Conditioning↗
PubMed1975

Regional myocardial infarction at operation. An automated system of identification.

The difference between normal and infarcted myocardium at operation cannot always be defected by inspection or palpation. Infarcted myocardium may be identified by a decrease in the amplitude of the ventricular bipolar electrogram. Although this method is reliable and reproducible, it requires a second observer's visual analysis and interpretation of the electrogram signal. This method is therefore subject to the vagaries of human observation, analysis, and accounts of rapidly changing data. We have designed and built an automated instrument to simplify the recognition of transmural infarction.

Animals↗