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Biomedical subjects

J Smith

Publications and source records attributed to J Smith.

At least 1,333 records · Page 74Linked to original sources
PubMed1979

Giant-cell tumor of the sacrum. Clinical and radiologic features in 13 patients.

Thirteen patients were found to have giant-cell tumors during a study of 91 primary tumors of the sacrum. This tumor was second only to the chordoma in incidence. Giant-cell tumor is by far the commonest benign lesion of the sarcrum, yet it has a bad prognosis. Recurrences occurred in seven patients and five died of disease or a complication. All were histologically benign when first seen, but one developed a malignant giant-cell tumor and died within two years, and one developed a radiation-induced sarcoma 10 years following treatment. Computed tomography in two recent patients proved to be the most valuable single examination. Arteriography is helpful in showing the degree of vascularity of the tumor and the exact position of the large vessels, particularly important when surgical resection is planned.

Adolescent↗
PubMed1979

Trichomycosis pubis.

Trichomycosis is a bacterial infection of hair that involves the axilla and, uncommonly, the pubis. The causative agent of trichomycosis pubis is probably the same as that in trichomycosis axillaris, as determined by culture and electron microscopy. We believe that increased awareness of trichomycosis pubis will show it to be common in certain environments.

Adolescent↗
PubMed1978

Photoelastic comparison of posterior denture occlusions.

The development of stress patterns was observed within a photoelastic model under complete mandidular dentures. Characteristic stress patterns were related to type of tooth material. Plastic teeth transmitted less force than porcelain teeth. Cusp teeth induced concentrated regions of force within the model that contrasted with the uniform distribution of force observed with flat teeth. The dentist should be aware of the biomechanical problems associated with any posterior denture occlusion in relation to the residual alveolar ridge.

Alveolar Process↗
PubMed1978

Fine structure of the rubrospinal terminals in the cervical cord of the cat.

Rubrospinal fibers in cat do not terminate on anterior motor horn cells in the spinal cord but on the interneurons, mostly in the lateral portion of Rexed's lamina of V-VII, the so-called Lateral Basal Region. The ultrastructure of rubrospinal terminals at the cervical cord level (C8) was investigated in 8 adult cats with partial or complete stereotaxic lesions of the red nuclei. Animals were sacrificed from 1 to 7 days after the lesions were made and the earliest forms of degeneration found were infrequent dense preterminal axon changes and clumping and coalescing of synaptic vesicles in the terminals. Multiple dense or polymembranous inclusions were seen in some terminals and these contained vesicular profiles; dense terminal shrinking was seen in others after 24 hours. Neurofilamentous proliferation appeared in some degenerating terminals after 48--72 hours. Degenerating terminals were related to different sized dendrites to determine regional axodendritic specificity for rubrospinal endings on LBR neurons.

Animals↗
PubMed1978

Adrenergic differentiation of cells of the cholinergic ciliary and Remak ganglia in avian embryo after in vivo transplantation.

We have previously shown that the neural crest is regionalized early into "adrenergic" and "cholinergic" areas from which arise, respectively, the sympathetic and parasympathetic ganglioblasts of the autonomic nervous system. This regionalization does not correspond, however, to an irreversible determination of the neural crest cells since, under certain experimental conditions, cholinergic cells can arise from the adrenergic region of the crest and vice versa. The phenotypic expression of the presumptive ganglion cells appears to be responsive to the environmental conditions they encounter during and/or after their migration. In the present study we show that the developmental behavior of parasympathetic ganglion cells which have stopped migrating and at least some of which have started to differentiate into cholinergic neurons can be profoundly modified if they are transplanted into a younger embryo at the trunk neural crest level. The crest level. The grafted ganglion cells start migrating and stop in the same sites as the host neural crest cells. Their further differentiation depends on their localization. When situated in the adrenergic ganglia and in the suprarenal gland they synthesize catehcolamines, whereas they differentiate into nonfluorescent, silver-staining ganglion cells if they migrate in the gut wall. Thus, the differentiation of autonomic neurons is dependent on tissue interactions even after the neural crest cells have grouped to form ganglionic structures in which biochemical differentiation is already in progress.

Adrenal Glands↗
PubMed1978

Nutritional inhibition of genetically determined renal disease and autoimmunity with prolongation of life in kdkd mice.

Striking inhibition of development of renal disease and prolongation of lifespan have been achieved in kdkd mice by restricting their daily food intake. Restricting protein intake alone did not prolong life nor did it inhibit development of kidney disease. The kdkd nephronophthisis, although very different histologically from the renal disease of B/W mice, may also have immunological components. Like the immunologically based renal disease of B/W mice, renal disease in kdkd mice is decreased or eliminated histologically by dietary restriction, which inhibits development of autoimmunity directed toward the erythrocytes of these mice. Further analysis will be needed to elucidate the cause of progressive renal disease in both the kdkd and B/W models and to permit understanding of the profound influence of restriction of food intake on development and progression of these very different renal diseases.

Animals↗
PubMed1978

Chondrosarcoma of the spine.

Involvement of the spine by chondrosarcoma is rare. Three recent cases involving the cervical with or without extension to the thoracic spine are reported. Detailed radiologic investigations to evaluate the extent of the disease are essential to management. Computerized axial tomography and angiography were performed in 1 case and were extremely helpful. Surgical resection of the lesion is the only currently effective method of treatment, but long-term survival figures are not good.

Adolescent↗
PubMed1978

Flow-cytometric analysis of chicken red blood cells.

Flow-cytometric analysis of acriflavin-Feulgen stained chicken erythrocytes shows a complex distribution of amounts of deoxyribonucleic acid fluorescence, the profile consisting of a main peak and a right hand shoulder. This bimodal distribution, an artifact characteristically seen on analysis of flattened cells using orthogonal flow systems, results from fluorescence emission in preferred directions stemming from the combined effects of refractility and orientation of the cells. The shoulder disappears on analysis of lysed erythrocyte ghosts, also on analysis of cells in a medium whose refractive index approximates that the cells. An orientation effect for matrue erythrocytes was indicated by reanalysis of fractions after sorting on the basis of high and low fluorescence or scatter signals. Both fractions gave the original range of values on reanalysis, although some changes in shape of the profile and in the peak positions for the sorted cells were seen. Sodium dodecyl sulfate treatment of stained cells "loosened" the cells' structure, yielding lowered scatter values, and fluorescence values approaching those of the shoulder. The average fluorescence emission of the erythrocytes was lower than that of reticulocytes and lymphocytes. The values of the latter correspond closely, although coincidently, to that the erythrocyte shoulder values. Dual parameter analysis of forward light scatter, and fluorescence, which was detected at 90 degrees to the laser beam, showed the low fluorescence to be accompanied by low scatter signal, and the high fluorescence among the cells with the high scatter signal. The lowered forward scatter signal is due to a wider scattering of light from cells oriented edge-on to the detector, and loss of signal beyond the acceptance angle of the detector. These results suggest that the preferred directions for fluorescence are in the plane of the cells, and the values are dependent on the cells' orientation in the stream. These interpretations were supported by the results of analysis of partially oriented cells. The approaches used and conclusions arrived at are similar to those of Gledhill et al (16), Van Dilla et al (37), in their analysis of fluorescence of flat sperm cells although the affects in the case of the erythrocytes are less extreme.

Animals↗