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Biomedical subjects

A Miller

Publications and source records attributed to A Miller.

At least 577 records · Page 32Linked to original sources

Self-defense as an exoskeletal coping mechanism in women.

Women enrolled in a Beginners' Judo-jujitsu class, as compared to women in Crafts, Physical Fitness, and Advanced Judo-jujitsu classes, were found to perceive the world as more threatening as measured by word lists involving bodily concern and fearfulness and to employ exoskeletal defenses as measured by adornment on the DAP. It was suggested that the exoskeletal coping mechanism may play an important role in the way in which women defensively handle threat.

Journal Article↗

Repertoires of T cells directed against a large protein antigen, beta-galactosidase. I. Helper cells have a more restricted specificity repertoire than proliferative cells.

The proliferative and helper T cell repertoires were compared in the CBA/J mouse for the response to the large protein antigen, tetrameric beta-galactosidase (GZ = 1021 a.a/monomer). The systems assessed the ability of cyanogen bromide (CB) peptides of GZ to: 1) prime for a T cell proliferative response to GZ; or 2) generate T cell help, measured by the production of anti-FITC PFC in the in vitro response to GZ-FITC. Priming for in vitro proliferation was attempted with 11 CB peptides comprising 70% of the GZ molecule. Strong priming was found with five peptides and intermediate priming was found with four other peptides; two peptides were without effect (CB-20 = a.a 767-862, and CB-4 = a.a. 188-202). Despite this indication of generally dispersed recognition of GZ epitopes, only two CB peptides, CB-2 (a.a. 3-92) and CB-10 (a.a. 378-418) were able to induce a T helper cell response. The surprising dearth of helper T cell-inducing epitopes may be peculiar to the limited fluorescein (FITC) substitution on GZ-FITC (17-25 FITC residues per tetramer) or it may reflect the constraints involved in T cell recognition required for T-B collaboration. Also considered was the possibility that the helper T cell repertoire might be distinct from the proliferative repertoire, the latter reflecting DNA synthesis and recruitment by other functional T cell subpopulations.

Animals↗

[Apropos of the 2nd case of cutaneous granuloma caused by Mycobacterium marinum in Uruguay].

A new, second uruguayan case of cutaneous granuloma by Mycobacterium marinum is presented. The patient a 31 years old white man from Montevideo city had two granulomatous and ulcerated lesions on the right knee, secondary to wounds suffered with mussels' shells 5 years before while cleaning his boat in saline waters close to our Rio de la Plata river. Diagnosis was made by finding the typical acid fast organisms in the lesions, the isolation of the agent in cultures and through experimental inoculation of laboratory animals. Metastatic nodular lesions were observed in hamsters (Mesocricetus auratus) after intratesticular inoculation. A clear improvement was obtained by local heat confirming previous observations.

Adult↗

Molecular and transport effects of 1,25-dihydroxyvitamin D3 in rat duodenum.

The saturable component of transmural calcium transport in rat duodenum is transcellular, dependent on vitamin D, and can be evaluated by in situ gut loops or everted sacs. Vitamin D action at the molecular level can be studied by analyzing the response in terms of calcium-binding protein (CaBP; Mr congruent to 9000) biosynthesis to exogenous 1,25-dihydroxyvitamin D3 (1,25-(OH)2-D3). In vitamin D-replete animals, the CaBP response occurs within 1 h of intraperitoneal injection when the animals have been fed a high-calcium diet (III), but in 7 h if the animals have been fed a low-calcium diet(I). The latter response appears to be transcriptional, whereas the former seems posttranscriptional. In vitamin D-deficient animals, exogenous 1,25-(OH)2-D3 evokes a CaBP response that occurs 7-8 h after treatment and is transcriptional in nature. Calcium uptake by isolated duodenal cells can be stimulated by prior in vivo treatment with 1,25-(OH)2-D3. Peak response times parallel those found with CaBP biosynthesis, i.e., 3 h in cells from vitamin D-replete animals fed diet III, 7 h in cells from vitamin D-replete animals fed diet I, and 12 h in cells from vitamin D-deficient animal. Cycloheximide treatment appears to inhibit these responses. Moreover, everted sacs from vitamin D-replete animals fed diets III and I show an early and a delayed transport response, respectively. Studies with brush border membrane vesicles prepared from rat duodenum have shown calcium uptake to be vitamin D-dependent. Part of this uptake involves binding to the inner aspect of the membrane and may involve a high-affinity CaBP. Thus a major component of the action of vitamin D in stimulating calcium transport appears to involve protein synthesis. The time and molecular nature of these responses depend on the calcium intake and vitamin D status of the animals. A model of calcium movement through the intestinal cell is included.

Animals↗

Idiotypic repertoire of anti-hen eggwhite lysozyme antibodies probed with hybridomas. Selection after immunization of an IdX marker common to antibodies of distinct epitope specificity.

A panel of hybridoma antibodies obtained from lymphoid cells that were fused during a primary response ("early") or a secondary response ("late") gave results concordant with analysis of conventional, in vivo-produced anti-lysozyme idiotypes: early antibodies did not display the predominant anti-hen eggwhite lysozyme idiotype (IdX-HEL), whereas late antibodies all displayed IdX-HEL. Furthermore, individual late hybridomas could each remove the entire anti-IdX-HEL activity by absorption, whereas early hybridomas could not. The epitope specificities of the hybridomas in both the early and late populations were heterogenous. We conclude that epitypic specificity in the response to HEL is determined independently from idiotypic specificity and that the predominant idiotype is selected for during the maturation of the anti-lysozyme response.

Animals↗

Correlation of spectral phonoangiography and carotid angiography with gross pathology in carotid stenosis.

Spectral phonoangiography, a noninvasive method for measurement of the residual-lumen diameter of carotid stenosis by bruit analysis, was compared with x-ray angiography and direct measurement of the pathological specimen at carotid endarterectomy in 39 bifurcations from 36 patients. In six studies, the bruit was too faint to analyze. In 31 of the other 33 studies, the phonoangiogram predicted the residual-lumen diameter to within 0.5 mm of the measured value. Of the 39 contrast angiograms, 35 showed residual lumens within 0.5 mm of the value measured in the specimen, two showed lumens between 0.5 and 1 mm, and the sizes of two could not be estimated because of vessel overlap in all planes. Spectral phonoangiography and contrast angiography are both accurate methods for evaluation of carotid stenosis. Since phonoangiography is noninvasive, it may be of particular value in determining the natural history in patients with carotid bruits.

Auscultation↗

Substance P immunoreactive sensory nerves supply the rat iris and cornea.

The presence, distribution and origin of substance P immunoreactive axons in the rat iris and cornea were investigated in whole mount preparations. A dense network of substance P immunoreactive axons was found throughout the iris but not in the ciliary body. In the cornea, substance P immunoreactive axons were found in the substantia propria, in the subepithelial layer and in the corneal epithelium. Following electrocoagulation of the ophthalmic nerve, most of the substance P immunoreactive axons in the iris and cornea disappeared. No changes in the substance P immunoreactive axons occurred after removal of the superior cervical ganglion. It is concluded that the iris and the cornea are supplied by sensory nerves containing substance P immunoreactivity.

Animals↗

Calcium uptake in isolated brush-border vesicles from rat small intestine.

Ca2+ uptake in brush-border vesicles isolated from rat duodena was studied by a rapid-filtration technique. Ca2+ uptake showed saturation kinetics, was dependent on the pH and ionic strength of the medium and was independent of metabolic energy. Uptake activity was readily inhibited by Ruthenium Red, La3+, tetracaine, EGTA, choline chloride and Na+ or K+. The effect of variations in medium osmolarity on Ca2+ uptake and the ionophore A23187-induced efflux of the cation from preloaded vesicles indicated that the Ca2+-uptake process involved binding to membrane components, as well as transport into an osmotically active space. Scatchard-plot analyses of the binding data suggested at least two classes of Ca2+-binding sites. The high-affinity sites, Ka = (2.7 +/- 1.1) x 10(4) M-1 (mean +/- S.D.) bound 3.2 +/- 0.8 nmol of Ca2+/mg of protein, whereas the low-affinity sites (Ka = 60 +/- 6 M-1) bound 110 +/- 17 nmol of Ca2+/mg of protein. In the presence of 100 mM-NaCl, 1.7 and 53 nmol of Ca2+/mg of protein were bound to the high- and low-affinity sites respectively. Decreased Ca2+-uptake activity was observed in vesicles isolated from vitamin D-deficient as compared with vitamin D-replete animals and intraperitoneal administration of 1,25-dihydroxycholecalciferol to vitamin D-deficient rats 16 h before membrane isolation stimulated the initial rate of Ca2+ uptake significantly. The data indicated that Ca2+ entry and/or binding was passive and may involve a carrier-mediated Ca2+-uptake component that is associated with the brush-border membrane. Altering the electrochemical potential difference across the membrane by using anions of various permeability and selected ionophores appeared to increase primarily binding to the membrane rather than transport into the intravesicular space. Since there is considerable binding of Ca2+ to the vesicle interior, a comprehensive analysis of the transport properties of the brush-border membrane remains difficult at present.

Animals↗

Location and effect of procaine on lecithin/cholesterol membranes using X-ray diffraction methods.

X-ray diffraction studies were made on lecithin/cholesterol multilayers with very high water content and containing the local anaesthetic procaine. Narrow-angle diffraction experiments show that the procaine molecules are located with the uncharged aromatic amine group approx. 10 A from the centre of the bilayer. The polar tertiary amine group of these molecules is almost certainly located in the polar head-group region of the membrane. Wide-angle diffraction experiments show that the incorporation of procaine molecules into such lipid membranes produces an approx. 30% increase in the spread of acyl chain separation, although the average spacing between the chains is slightly reduced.

Chemical Phenomena↗

The vanishing lung syndrome associated with pulmonary sarcoidosis.

Two patients are reported with "vanishing lungs' associated with sarcoidosis or necrotizing sarcoid granulomatosis. This syndrome is a rare outcome of sarcoidosis, but sarcoidosis may be an underlying cause of giant bullous emphysema. If bullectomy is undertaken, tissue should be removed from relatively normal lungs and mediastinal nodes to demonstrate the presence and nature of any granulomas.

Adult↗