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Biomedical subjects

E Johnson

Publications and source records attributed to E Johnson.

At least 361 records · Page 20Linked to original sources
PubMed1980

Calcification of cultured urticaria pigmentosa skin. An electron optical study of the calcium-apatite deposition.

Mast cells participate in experimental calcinosis. Skin from patients with urticaria pigmentosa (cutaneous mastocytosis) calcifies in vitro. In the present report, the nature of the calcium deposit was studied by electron optical techniques. The cultured mast cells of urticaria pigmentosa skin were surrounded by a large number of round bodies with an average diameter of 200-300 nm. Most of the round bodies were membrane bounded, while a few contained lamellar structures. These bodies may represent matrix vesicles as seen in calcifying hard tissues and/or may be remnants of mast cell granules. The calcified deposits were located on the round bodies, collagen fibrils and elastic matrix. Electron diffraction and X-ray microanalysis demonstrated that the deposits consisted of crystalline calcium apatite.

Apatites↗
PubMed1980

Determination of organic acids in biological fluids by ion chromatography: plasma lactate and pyruvate and urinary vanillylmandelic acid.

We describe the general aspects of ion chromatography and how on-line counted ion-exchange techniques can be utilized to determine pyruvic and lactic acids in plasma and vanillymandelic acid in urine. Pyruvate and lactate are extracted from deproteinized plasma by use of an ion-exclusion resin. After elution from the resin, the plasma extract is chromatographed on an anion-exchange column, with 0.66 mmol/L sodium bicarbonate as the mobile phase. The effluent is detected with an electrical conductivity cell. Vanillylmandelic acid is extracted from diluted urine by use of an anion-exchange resin. After elution from resin, the urine extract is chromatographed on an ion-exclusion column, followed by electrochemical detection. We evaluated the procedures for precision, linearity, analytical recovery, intefering substances, and correlation with an established procedure. the combination of a preliminary resin extraction, an ion chromatographic separation, and a conductivity or electrochemical detector results in rapid, specific methods that can be adapted for use in the clinical laboratory. Preliminary data for other organic acids are presented.

Carboxylic Acids↗
PubMed1979

Calcification in a pineal tumour studied by transmission electron microscopy, electron diffraction and x-ray microanalysis.

The calcification in a totally calcified pineal tumour was studied. Transmission electron microscopy indicated that the tumour was a pinealoma. The type of calcification was investigated by bright-field and dark-field transmission electron microscopy in addition to electron diffraction and electron-induced x-ray fluorescence. The calcified material consisted predominantly of amorphous calcium phosphate. The type of calcification differs from the normal calcification present in pineal acervuli which consists of crystalline hydroxypatite.

Brain Neoplasms↗
PubMed1979

Dermatomyositis with universal calcinosis. A histopathological and electron optic study.

Biopsies from a 5-year-old girl with dermatomyositis and universal calcinosis were studied histopathologically and by means of electron optical techniques. The dermis was infiltrated by fibroblasts, lymphocytes and plasma cells. In the lower part of the dermis, dense basophilic areas were present. In the vicinity of these areas irregular elastic fibers appeared. In the electron microscope these elastic fibers appeared mineralized to varying degrees. The mineral part was identified as calcium apatite (either calcium-hydroxy-apatite or calcium fluoroapatite) by X-ray microanalysis and selected area diffraction. No calcification was observed outside the elastic fibers.

Calcinosis↗
PubMed1979

Differences in the susceptibility of MHC and non-MHC mixed lymphocyte reactions to suppression by murine amnionic fluid and its components.

The ability of mouse amniotic fluid (MAF), alpha-foetoprotein (AFP) and MAF depleted of AFP (MAF - AFP) to suppress primary one-way MLR's was investigated. It was found that MAF, AFP and MAF - AFP were all suppressive of MLR's specific for MHC, K, D or I + S determinants. Suppression was observed when either lymph node or spleen cells were used as the responder cells. Nylon wool column passage of these cells did not significantly affect the immunosuppressive action of these substances. In contrast, MLR's specific for non-MHC/M-locus determinants demonstrated either diminished suppression or augmentation of the response, compared with the MHC stimulated MLR's. Our results show a differential effect of whole MAF and its fractions on the proliferative responses induced by various allogeneic stimuli and suggest that suppression is not due to a non-specific effect on proliferation regardless of the stimulus or cell type involved.

Amniotic Fluid↗
PubMed1979

The ultrastructure of transmissible murine colonic hyperplasia.

Transmissible murine colonic hyperplasia was examined ultrastructurally by sequential sampling after inoculation with the etiologic agent, Citobacter freundii. Light-microscopic changes in the descending colon of inoculated mice were correlated with scanning and transmission electron-microsopic findings. Bacteria were attached to the surface of the mucosa between 4 and 10 days after inoculation. Hyperplasia was most severe at 16 days and thereafter underwent regression. Regression was preceded by extrusion of infected cells from the surface mucosa and replacement by immature hyperplasia epithelium. Hyperplastic epithelium throughtout the crypt resembled undifferentiated crypt cells of controls. By 45 days, the mucosa had reverted to near normal structure. The results suggest that severe mucosal proliferation with minimal inflammatory change resulted from attachment of bacteria to the surface mucosal epithelium. The hyperplastic response appeared to be a defense mechanism of replacing infected cells with newly migrated, uninfected epithelium.

Animals↗
PubMed1978

Group teaching of auscultation. Use of a new wireless stethoscope-type headphone.

A new technique using infrared light for the transmission of heart sounds and murmurs is described. This method enables the simultaneous transmission of heart sounds and murmurs to large groups of persons without the need for hard-wire connections to the amplifying device. The method facilitates teaching of cardiac auscultation at the bedside as well as in the setting of conferences, seminars or postgraduate education programs.

Audiovisual Aids↗
PubMed1978

Longevity in military pilots: 37-year followup of the Navy's "1000 aviators".

The 37-year nonmilitary mortality rate for initially healthy aviators was determined in a followup program on the U.S. Navy's "1000 Aviator" cohort. Of the 800 survivors of World War II and the Korean conflict, 95 were found to have died from nonmilitary causes over this followup period. This is markedly less than the 208 that would be expected from a random sample of white American men over a similar period (p less than 0.005). It is also significantly less than the 143 that would have been expected from a group of men who had passed an initial insurance physical (p less than 0.005). Lower-than-expected death rates occurred in all three major categories of cause of death in this age group: cardiovascular, neoplastic, and accidental. The generally good socioeconomic background, the positive genetic influence of long-lived parents, the above average intelligence, and the health and fitness orientation of the military aviator are all thought to be factors contributing to this increased longevity.

Accidents↗
PubMed1978

Salpeter-induced dermal changes electron-microscopically indistinguishable from pseudoxanthoma elasticum.

Salpeter-induced calcium deposits in ten patients showed a close clinical and histopathological similarity to the lesions of pseudoxanthoma elasticum. By electron microscopy and selected area diffraction analyses of the calcium deposits we find the changes indistinguishable from the changes previously described in involved skin of patients suffering from PXE. Clinically our patients were compared with the fourteen patients with traumatic calcification previously described.

Aged↗
PubMed1977

Apatite crystals in pseudoxanthoma elasticum: a combined study using electron microscopy and selected area diffraction analysis.

Calcium deposits in elastic fibers of involved skin of patients suffering from pseudoxanthoma elasticum have previously been reported. In the present work, the crystalline structure and composition were studied. Involved skin was obtained from 5 patients. Bright-field and dark-field electron microscopy and selected area electron diffraction of the calcium deposits were applied. The study demonstrates calcium apatite crystals.

Apatites↗
PubMed1977

Metabolism of testosterone by forehead skin of the roebuck (Capreolus capreolus).

Roebucks have a specialized region of skin on the forehead which contains sebaceous and apocrine glands that produce secretions used in territorial marking. These glands enlarge during the breeding season and regress after the rut as the testes regress. The metabolism of testosterone by this forehead skin in vitro was studied in two captive roebucks over the period of glandular enlargement and subsequent regression, and compared with that of dorsal skin. In May, June and July, both areas of skin actively metabolized testosterone and the metabolites detected were androstenedione, androstanedione, dihydrotestosterone, epiandrosterone, androsterone and 5alpha-androstanediols. There were no major differences in testosterone metabolism between the two body sites, although dorsal skin appeared to be more active in total metabolism than forehead skin. There was a peak in the extent of metabolism in June/July, with a subsequent gradual decline to December. The decline in metabolism occurred at a time when the associated glands were still enlarged, which suggests that the availability of androgen to the skin glands is determined not only by the amount of testosterone in the circulation, but also by a decrease in the metabolizing capacity of the tissue.

Androstenedione↗