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Biomedical subjects

R E Gordon

Publications and source records attributed to R E Gordon.

At least 145 records · Page 8Linked to original sources
PubMed1981

In vivo carbon-13 nuclear magnetic resonance studies of mammals.

Natural abundance carbon-13 nuclear magnetic resonances (NMR) from human arm and rat tissues have been observed in vivo. These signals arise primarily from triglycerides in fatty tissue. Carbon-13 NMR was also used to follow, in a living rat, the conversion of C-1-labeled glucose, which was introduced into the stomach, to C-1-labeled liver glycogen. The carbon-13 sensitivity and resolution obtained shows that natural abundance carbon-13 NMR will be valuable in the study of disorders in fat metabolism, and that experiments with substrates labeled with carbon-13 can be used to study carbohydrate metabolism in vivo.

Adipose Tissue↗
PubMed1981

31P-NMR investigation of solid tumours in the living rat.

The 31P-NMR spectra of living tumours (Walker 256 carcinosarcomas) have been obtained using surface coils and found to be unlike those of normal tissues. Contrary to expectations, their intracellular pH (measured from the chemical shift of the inorganic phosphate peak) was only slightly more acid than that of normal rat muscle, and glucose infusion did not depress it. However, when deoxyglucose was infused, the tumour intracellular pH measured from the chemical shift of the deoxyglucose-6-phosphate peak was much lower (6.44 +/- 0.02) than that measured from the phosphate peak (7.14 +/- 0.01).

Animals↗
PubMed1981

Chronic GM2 gangliosidosis masquerading as atypical Friedreich ataxia: clinical, morphologic, and biochemical studies of nine cases.

A progressive spinocerebellar degenerative disorder was characterized in nine patients, aged 11 to 37 years, from four unrelated Ashkenazi Jewish families; affected individuals had markedly deficient beta-hexosaminidase A activity. Symptoms included early onset of cerebellar signs (tremor, incoordination, and dysarthia) and, with maturity, the development of upper and lower motor neuron disorders, marked dysarthia, and ataxia. Three older patients, aged 26, 32, and 37 years, had dementia or recurrent psychotic episodes. Membrane-bound lamellar cytoplasmic inclusions, consistent with lysosomal ganglioside accumulation, were observed in rectal ganglia. The activity of beta-hexosaminidase A was markedly deficient in all sources analyzed. Parents had activities consistent with heterozygosity, confirming autosomal-recessive transmission of the beta-hexosaminidase A-deficient gene and the adult variant disorder. Residual beta-hexosaminidase A activity, partially purified by anion-exchange chromatography from cultured skin fibroblasts of the affected individuals, was heat-labile and co-electrophoresed with normal beta-hexosaminidase A. These findings suggest that these patients were allelic for a new beta-hexosaminidase A mutation and may represent a genetic compound of this allele and the allele causing Tay-Sachs disease.

Adolescent↗
PubMed1980

Localization of metabolites in animals using 31P topical magnetic resonance.

High-resolution phosphorous (31P)-NMR spectra of biological molecules provide detailed information about the metabolism of living systems. Although the NMR method is non-destructive, all studies so far, with two exceptions, have been carried out on excised, perfused organs and tissues or have required some form of surgery for in situ measurements. The use of 'surface' radiofrequency coils does not require surgery, but is best suited for tissues close to the surface of the animals. We describe here 'topical magnetic resonance'--a new, non-surgical method for acquiring 31P-NMR spectra from a selected, localized place deep within an animal by modifying the main magnetic field, B0, using only static-field gradients. The method is conceptually similar to one spin-imaging method but primarily provides biochemical rather than spatial information. This new technique can be used in fundamental investigations into living systems, clinical diagnosis and the estimation of the efficacy of drug therapy.

Adenosine Triphosphate↗
PubMed1980

Primary mucinous carcinoma of the thyroid gland: report of a case and ultrastructural study.

A follicular carcinoma of the thyroid with extensive mucin production was found in a 54-year-old woman. The primary nature of this rare neoplasm of the thyroid gland is supposrted by the presence of both colloid and mucin-producing follicles. Ultrastructural features confirm the secretion of colloid and mucin in the same neoplastic thyroid cells.

Adenocarcinoma, Mucinous↗
PubMed1980

Identification of nocardiae and streptomycetes of medical importance.

During a taxonomic investigation of Nocardia spp. and Streptomyces spp., we received 658 isolates from laboratories of both human and veterinary medicine. Our procedure leading to the identification of 92% of these isolates, the species that they represented, and a characteristic pattern of properties of the strains of these species are presented. A key devised for the tentative identification of species of nocardiae and streptomycetes that are believed to be of medical importance is included to assist clinical microbiologists in identifying their strains.

Bacteriological Techniques↗
PubMed1980

Identification of contractile proteins in basal bodies of ciliated tracheal epithelial cells.

To determine the molecular composition of the components of basal bodies and the interbasal body apparatus of ciliated cells in rat tracheal epithelium, we used rabbit anti-actin, anti-alpha-actinin, anti-tropomyosin, and anti-myosin as primary antisera applied to the tissue in an indirect immunoperoxidase technique. The antisera was proven to be monospecific by elution of antibody after affinity chromatography. Sheep anti-rabbit immunoglobulin Fab fragments coupled to peroxidase were used for ultrastructural localization of the bound rabbit antibody. Antibodies against alpha-actinin were demonstrated around peripheral microtubules of cilia and linking these microtubules to central doublet and plasma membrane. Alpha-actinin was also shown in the basal foot processes. Anti-actin antibodies were associated with microtubules of the cilium and basal bodies, except in the region of the ciliary necklace. The antibodies directed against actin also had affinity for rootlets, basal foot processes, and communications between basal bodies and foot processes. Both anti-myosin and anti-tropomyosin antibodies were localized to part of the region of the constriction of the cilium, to the central basal density and the outer surfaces of basal body microtubules, and to the basal foot processes together with their communications to the basal body. The data suggest active contractile function of basal bodies.

Animals↗
PubMed1980

Localization of factor-VIII-related antigen in human vascular subendothelium.

Factor-VIII-related antigen has previously been shown to be synthesized by vascular endothelial cells. Using both an immunofluorescent staining technique and electron microscopy, we have demonstrated the presence of factor-VIII-related antigen in human vascular subendothelium. This finding may have implications in the mechanism of platelet adhesion to deendothelialized blood vessel surfaces.

Animals↗
PubMed1980

Duration of cell cycle and its phases measured in synchronized cells of squamous cell carcinoma of rat trachea.

Synchronization of tumor cells can facilitate measurement of cycle time and permit identification of subpopulations which deviate from the average in either total cycle time or duration of specific phases. We utilized exposure to high concentrations of thymidine to arrest cycling cells in tumor fragments in culture. Pieces of six squamous cell carcinomas, induced in heterotopically transplanted rat tracheas by exposure to benzo(a)pyrene, were placed in culture and subjected to two sequential thymidine blocks. The labeling indices in cultures studied at 2 and 8 hr after release from the second block were equal to the growth fractions. By 16 hr after release from the block, no DNA synthesis was observed in any culture. In three tumors for which cycle and cycle phase duration was measured, mitosis occurred synchronously 12 hr after release from the thymidine block, and a second period of DNA synthesis began 16 hr later. Tc was 28 hr, Ts averaged 9 hr, Tg1 averaged N hr, and Tg2 averaged 3 hr, allowing 1 hr for TM. These numbers correspond to the values for normal cells participating in wound healing in this epithelium. There were also no deviant populations present. The cycle and its phases therefore cannot serve as markers for cancer in this tissue, but the degree of synchrony achieved will permit correlative studies of phase-specific cell properties which have been suggested as candidates for markers of cancer.

Animals↗
PubMed1979

Regeneration of vitamin A deficient rat tracheal epithelium after mild mechanical injury. Growth kinetics and cellular differentiation.

Mild mechanical abrasion of tracheal epithelium of Vitamin A deficient rats removed the superficial cells and spared basal cells which divided to repopulate the damaged area. The proliferative cells passed through a period of DNA synthesis with the greatest numbers of thymidine incorporating cells in samples labelled 22 h after injury. A peak of cell division occurred at 32 h and there was no further DNA synthesis or cell division. The area of wounding exhibited squamous metaplasia while normal pseudostratified muco-ciliary structure was retained by adjacent epithelium which had not been injured. The data indicates that squamous metaplasia in the respiratory epithelium in longstanding Vitamin A deficiency is due to redirected differentiation of basal cells and is seen only after mitotic activity has occurred.

Animals↗
PubMed1979

Development of tight junctions in rat tracheal epithelium during the early hours after mechanical injury.

Mild abrasion of rat tracheal epithelium results in the death of superficial cells and flattening of basal cells to cover the exposed areas of basal lamina. Six hours after injury, colloidal tracers were shown in previous studies to be excluded from the spaces between cells and from the underlying lamina propria. The structural basis for this restoration of barrier function was investigated in the present experiments using transmission electron microscopy of thin sections and freeze fracture replicas. For each of 4 elapsed times after injury, 12 healing lesions in the epithelium were studied extensively. In specimens obtaine 2 and 4 hours after wounding, apical junctions between epithelium cells could not be identified in either thin sections or freeze fracture replicas. Six hours after injury, point contact could be recognized between epithelial cells in thin sections, whereas freeze fracture replicas revealed rudimentary tight junctions consisting of fragmented strands and linearly organized particles. Twelve hours after injury, highly developed tight junctions similar in complexity to those in normal uninjured tracheal epithelium were observed between the relatively undifferentiated basal cells comprising the regenerating epithelium. The focal membrane modification that appears 6 hours after injury is thus an early step in the process of regeneration and restoration of cytologic specialization.

Animals↗