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Biomedical subjects

J J Taylor

Publications and source records attributed to J J Taylor.

At least 55 records · Page 3Linked to original sources
PubMed1985

Effect of phenytoin and/or beta-aminoproprionitrile on a surgically induced periosteal wound.

Phenytoin has a beneficial effect on wound healing and on the healing of bone fractures, while beta-aminopropionitrile (BAPN) has an adverse effect on both. BAPN causes what appears to be a repair response in the periosteum at sites of muscle attachment, but phenytoin does not alter that response. The effect of phenytoin and/or BAPN on the repair of a surgically induced periosteal wound at the insertion of the adductor longus and pectineus muscles was studied in rats at 7 days post-wounding. Phenytoin facilitated and BAPN exacerbated the repair process, as indicated by the size of the periosteal response. Phenytoin increased the percentage of bone present in the responses, and both phenytoin and BAPN reduced the amount of cartilage present. The possible role of inflammation in obtaining the beneficial effects of phenytoin in wound healing is discussed.

Administration, Oral↗
PubMed1984

Blocking activity to action of thyroid stimulating hormone in serum from patients with primary hypothyroidism.

Spontaneous primary hypothyroidism in adults is usually associated with autoimmune thyroiditis. The hypothesis that hypothyroidism may result from the presence in serum of a factor that blocks stimulation of the thyroid by thyroid stimulating hormone was examined. Serum samples were collected from 28 patients with recently diagnosed primary hypothyroidism. After removal of endogenous thyroid stimulating hormone the effect of the serum on secretion of triiodothyronine induced by thyroid stimulating hormone or thyroid stimulating antibodies was examined in thyroid slices incubated in vitro. Serum samples from six of the patients demonstrated significant blocking of the stimulation by bovine thyroid stimulating hormone. Inhibition of the stimulatory action of thyroid stimulating antibodies was also exhibited by serum samples with blocking activity. It is concluded that in some patients with primary hypothyroidism a serum factor, which is probably an IgG, exists that can block the thyroid response to thyroid stimulating hormone and thyroid stimulating antibodies; it may represent an important mechanism in the pathogenesis of hypothyroidism.

Adult↗
PubMed1983

Specific epidermal growth factor receptors on porcine thyroid cell membranes.

Specific saturable receptors for epidermal growth factor (EGF) of high affinity (Ka 1.7 X 10(9) M-1) have been demonstrated on porcine thyroid membranes. Optimal conditions for EGF binding have been determined. TSH and other peptide hormones do not inhibit the binding of 125I-EGF and EGF does not inhibit 125I-TSH binding to thyroid membranes. The results suggest that EGF may be involved in the regulation of thyroid follicular cell growth and function.

Animals↗
PubMed1978

Neurofibrillary tangles in experimental neurolathyrism in rats induced by imino-dipropionitrile (IDPN). 1. Fine structural changes in the spinal cord and dorsal root ganglia.

Anterior horns of the spinal cord from cervical and lumbar regions and dorsal root ganglia from these same levels were studied for ultrastructural changes in imino-dipropionitrile (IDPN) treated rats. Normal saline-injected rats, treated identically, served as controls for this study. In the spinal cord axonal balloons or dystrophic axons appeared in lightly myelinated or unmyelinated axons within 24 h after the third injection of IDPN. At this time hind leg paralysis had not yet developed. In addition to axonal changes, a few dendrites also showed neurofibrillary degeneration. Central chromatolytic changes were observed in most of the neurons, with evidence of generalized edema present within the cord. In the dorsal root ganglia axonal balloons were very prominent and showed neurofibrillary hypertrophy. Neurofibrillary material was also noted in the perikarya of medium-sized ganglion cells.

Animals↗
PubMed1978

The pacemaker cell of the sinoatrial node of the rabbit.

Rabbit sinoatrial nodes were isolated and studied in an attempt to determine the cell of origin of the true pacemaker potential. Cells of the sinoatrial node of the rabbit giving rise to the characteristic true pacemaker potential were iontophoretically tagged with lanthanum. The lanthanum appeared within the cytoplasm of cells, which morpholigically are "P" cells. The lanthanum appeared as small, amorphous, electron-dense globules. It is concluded from this study that the P or pale cell is the source of the true pacemaker action potential of the sinoatrial node.

Action Potentials↗
PubMed1978

Electron-microscopic study of the maturing rat red nucleus. I. The large-neuron population.

The maturing large neurons of the rat red nucleus in animals ranging in age from 1 to 21 days of postnatal life were studied ultrastructurally. Days 1--6 were characterized by rapid morphologic maturation occurring concomitantly with the onset of synaptogenesis. Morphogenesis was confined to the soma, while the first synaptic contacts were also formed in relationship to the soma. Days 6--9 demonstrated continued somal morphogenesis exemplified by cytoplasmic expansion and by the conspicuous presence of perisomatic and growth cone processes. Proximal dendritic morphogenesis was initiated, and synaptogenesis became complex with synaptic sites occurring in relation to the neuronal soma, the perisomatic processes and proximal dendrites. Days 9--15 were characterized by the completion of somal and proximal dendritic morphogenesis and by a massive degree of synaptogenic activity. During this interval, the soma lost perisomatic and growth cone processes, while somatic spines appeared. By the end of this period the neuronal soma and the proximal dendrites appeared mature in terms of both morphology and synaptic input. Complete neuronal maturation was ultimately attained by day 21 of postnatal life.

Animals↗
PubMed1977

Immune complex disease. VI. Some determinants of the varieties of glomerular lesions in the chronic bovine serum albumin-rabbit system.

Glomerular lesions were evaluated by light, electron, and immunofluorescence microscopy in rabbits given daily injections, for prolonged periods of time, of either 12.5 mg. of bovine serum albumin (BSA) (group I) or increasing doses of BSA, paralleling the immune response (group II). In animals clearing 12.5 mg. or more of BSA per day (excluding those dying of anaphylaxis or unknown causes), marked differences were noted in the incidence of membranous glomerulonephritis (GLN) (50 per cent in group I versus 15.4 per cent in group II), of crescentic GLN (none in group I versus 26.9 per cent in group II), and of mesangiopathic GLN (11.1 per cent in group I versus 30.8 per cent in group II). On the basis of these variations and immunofluorescence microscopy findinds, it is concluded that the occurrence of membranous GLN is favored by the presence in the circulation of small concentrations of soluble immune complexes, whereas crescentic GLN results from the presence of high concentrations of such complexes. When BSA injections were discontinued in group I animals having membranous GLN, the immune deposits were sequestered by membranous transformation so that they were not readily solubilized by injections of large amounts of BSA; one such animal developed crescentic GLN. The observation that BSA was difficult to detect in the lesions of mesangiopathic GLN suggests that this lesion results from the deposition of complexes formed at equivalence or in antibody excess.

Animals↗
PubMed1976

Ex vivo determination of potentially virulent Sporothrix schenckii,.

Hyphae from 30 isolants of Sporothrix and Ophiostoma species were washed, dried and pyrolyzed at 350 degrees C. Pyrolysis products were separated on a Carbowax column heated 7.5 degrees C/min to and maintained for 50 min at 160 degrees C. Hydrogen flame detector responses were recorded graphically. Fifteen clinical isolants of S. schenckii from geographically separated sources produced qualitatively identical pyrograms. S. foliorum, 8 avirulent S. schenckii and other Sporothrix species isolants from soils, and Sporothrix states of 6 Ophiostoma species yielded pyrograms readily distinguished from each other and from those of virulent S. schenckii. Taxonomic and clinical implications of the pyrograms are mentioned.

Ascomycota↗
PubMed1976

An ultrastructural study of sympathetic ganglion satellite cells in the rat. 2. Effect of preganglionic sympathectomy.

The ultrastructure of satellite cells of the rat superior cervical ganglion was studied following preganglionic sympathectomy.Several distinct morphological alterations were observed: (a) enlargement of the intercellular space between the ganglion cells and the satellite cells, (b) dilation of the granular endoplasmic reticulum and loss of attached ribosomes, and (c) swelling of the mitochondria with disorganization of the cristae mitochondriales. The presence of degenerating nerve fibers and synaptic boutons was also noted.

Animals↗
PubMed1976

Dilute ethyl alcohol: effect on the sciatic nerve of the mouse.

The histological changes produced in peripheral nerve by topical ethyl alcohol have been infrequently studied in spite of widespread use of this neurotoxic agent in the management of pain and spasticity. In the present study the sciatic nerves of a series of albino mice were exposed to ethanol in concentrations of from 10% to 50% for from 15 to 60 seconds. An immediate physiochemical reaction took place, resulting in splitting of myelin sheaths and swelling of cellular organelles and cytoplasm. Nerves subsequently underwent Wallerian degeneration. A central core of fibers appeared to be normal. The longer exposure times or higher alcohol concentrations increased the extent to which the peripheral rim of altered tissue extended centrally into the nerve. Within altered tissue, all fiber types and sizes were found to be affected to an equal degree. To study the physical properties of alcohol in solution, absolute alcohol was slowly placed at the bottom of a cylinder filled with artificial or normal human spinal fluid and sequential levels of the solution were sampled 30 and 60 seconds after injection. Though hypobaric, alcohol dispersed rapidly so that specimens taken from the bottom of the cylinder were 65% as concentrated as specimens taken from the surface.

Animals↗
PubMed1976

Phlebotomy and iron deficiency.

Therapeutic and investigational phlebotomy can produce iron deficiency severe enough to warrant iron therapy or even replacement blood transfusion. This complication of modern medicine is not adequately recognized.

Anemia, Hypochromic↗
PubMed1975

An unusual membrane-bound body in rat periosteal cells.

Cytoplasmic inclusions have been found in both normal and stimulated rat periosteal cells. These inclusions are bounded by a pentilaminar membrane similar to a tight junction and contain a core of granular material. The origin and function of this inclusion are unknown.

Animals↗
PubMed1975

Massive splenomegaly, pancytopenia and haemolytic anaemia in sarcoidosis.

A 53-year-old dock labourer, presented with massive splenomegaly and subsequently developed pancytopenia. Complete haematoglogical remission was observed following splenectomy. Histological examination of the liver and spleen revealed sarcoid granulomata. A year after splenectomy, he died in an acute haemolytic crisis, a very rare complication of sarcoidosis. Evidence of generalized sarcoidosis was found at autopsy. The literature on haematological complications in sarcoidosis is reviewed.

Anemia, Aplastic↗