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Biomedical subjects

R Mortimer

Publications and source records attributed to R Mortimer.

At least 19 recordsLinked to original sources
PubMed1989

Steatohepatitis associated with limb lipodystrophy.

Two patients who presented with steatohepatitis had acquired partial lipodystrophy. This association has not previously been well documented. A common pathophysiological mechanism in lipodystrophy, obesity-associated nonalcoholic steatohepatitis, and alcoholic liver disease is possible.

Adolescent↗
PubMed1988

Screening for thyroid malignancy: the role of fine-needle biopsy.

Cytological examination of the aspirate of fine-needle biopsy is becoming more widely accepted as a screening test for malignancy in thyroid nodules. However, it tends to be used in addition to, rather than instead of, more traditional methods. In this five-year prospective evaluation we performed fine-needle biopsy in 618 euthyroid patients with nodular thyroid enlargement, 86% of whom also underwent radionuclide scans and 55% of whom underwent ultrasound scans. In 19% of patients fine-needle biopsy yielded insufficient material for diagnosis, and in 14% of patients normal follicular cells were found (which indicated that the clinical lesion was not sampled). To date, a histological diagnosis has been obtained in 258 (42%) patients, 44 of whom had malignancies. The results of the radionuclide and ultrasound scans did not alter the odds in favour of the detection of malignancy. The cytological diagnosis of malignancy was falsely-positive in two patients and falsely-negative in four patients (three cases of which probably were sampling errors). If, in addition to overtly-malignant cells, atypical Hürthle cells and follicular neoplasms were considered to be potentially malignant, fine-needle biopsy alone had a sensitivity of 87% and a specificity of 72%. This good accuracy would be reduced by sampling failures, but a policy of operating on all patients with potentially-malignant cells, or on those in whom satisfactory aspirates could not be obtained, would yield high rates of the diagnosis of malignancy and would reduce the number of operations. Our data indicate that the most-appropriate method of screening thyroid nodules for malignancy is fine-needle biopsy without pertechnetate scanning or ultrasound examinations.

Australia↗
PubMed1983

Serum thyroglobulin after mantle irradiation for Hodgkin's disease.

Thyroid function and serum thyroglobulin levels were studied in 66 subjects whose Hodgkin's disease had been previously treated by cervical, mediastinal and axillary lymph node (mantle) irradiation. Three patients were already undergoing treatment for thyroid disorders (one for primary hypothyroidism, two for Graves' disease) and a fourth was found to have euthyroid Graves' disease. 36 (Group I) of the remaining 62 patients had normal free thyroxine indices, normal basal thyrotrophin (TSH) levels and normal TSH response to thyrotrophin releasing factor (TRH). In 20 patients (Group II) free thyroxine indices were normal but either basal TSH levels were raised or normal basal TSH levels were associated with an exaggerated response to TRH. In 6 patients (Group III) free thyroxine indices were subnormal. Although results of thyroid function tests in group I lay within the normal range, the mean free thyroxine index was significantly lower and mean basal and peak TSH levels were significantly higher than those of a group of 35 normal subjects, indicating mild thyroid hypofunction. Elevated thyroglobulin levels were demonstrated in 11 irradiated subjects (18%). Mean thyroglobulin levels were significantly raised in each of the three groups of irradiated subjects. Significant positive correlations were found between log serum thyroglobulin and log basal TSH (r = 0.453, P less than 0.001) and log peak TSH (r = 0.515, P less than 0.001) levels. Mild thyroid hypofunction is common after mantle irradiation for Hodgkin's disease and raised serum thyroglobulin levels are a sensitive indicator of TSH stimulation of the damaged thyroid gland.

Adolescent↗
PubMed1981

Variation in frequency of transformation by plasmid YRp7 in Saccharomyces cerevisiae.

Hybrid plasmid YRp7 (Escherichia coli plasmid pBR322 carrying a 1.4-kb yeast fragment containing the TRP1 gene) transforms two related haploid yeast strains (trp1) to Trp+ at frequencies per microgram DNA varying by two orders of magnitude. The diploid cross of these two strains is transformed at a frequency less than that of the low-frequency parent, indicating that high-frequency transformation is inherited in a recessive fashion. Segregant strains of two tetrads of this cross showed intermediate levels of transformability, suggesting the polygenic inheritance of transformation frequency. Levels of variation are changed extensively when frequencies are expressed as transformants per regenerated spheroplast colony, although the inheritance of higher frequency remains clearly recessive. Storage of spheroplast-DNA preparations at 4 degrees C increases the yield of transformants with some strains.

Cold Temperature↗
PubMed1977

High elevations of creatine phosphokinase in hypothyroidism. An isoenzyme analysis.

In hypothyroidism, slight elevations of serum creatine phosphokinase (CPK) levels are common. In contrast, we describe six hypothyroid patients with extreme elevations (17- to 160-fold) of CPK levels. Enzyme analysis showed only MM isoenzyme in four cases and MM plus trace MB isoenzyme in two patients. Hypothyroidism should, therefore, be considered when elevated CPK levels, even extreme, are found. Isoenzyme analysis in such a case will show primarily an MM pattern, although trace MB fraction can also be seen. This isoenzyme pattern suggests that the sources of the CPK elevations is skeletal muscle.

Adult↗
PubMed1975

Mutant of the yeast Saccharomycopsis lipolytica that accumulates and excretes protorphyrin IX.

The red, water-insoluble pigment excreted by a mutant strain of the yeast Saccharomycopsis lipolytica is show to be protoporphyrin IX. In genetic crosses the red phenotype has the properties characteristic of a defect in a single, recessive nuclear gene. The yield and ease of harvest of protoporphyrin IX from the yeast mutant indicate that this strain or its derivatives may be a valuable source of this substance.

Acetates↗
PubMed1971

Genetic order of the galactose structural genes in Saccharomyces cerevisiae.

The galactose structural genes of Saccharomyces cerevisiae were ordered by determining the genotypes of mitotic and meiotic recombinants from crosses heterozygous for the three genes. The most probable order is centromere-gal7-gal10-gal1. Nonreciprocal recombination was more frequent than reciprocal exchange, and both mitotic and meiotic co-conversions involving mutant sites in all three genes were observed.

Chromosome Mapping↗
PubMed1971

Complementation and genetic recombination in Candida lipolytica.

Nutritional requirements were introduced into wild-type, heterothallic strains of Candida lipolytica by exposing the cells to X rays. Complementing hybrids were recovered from mixtures of the auxotrophic strains, and genetic recombination was observed in individually isolated ascospores from the hybrid strains.

Canavanine↗
PubMed1969

Stool collection.

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Equipment and Supplies↗