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Biomedical subjects

S Taylor

Publications and source records attributed to S Taylor.

At least 379 records · Page 21Linked to original sources
PubMed1987

Development of plasmacytoid cells with Russell bodies in autoimmune "viable motheaten" mice.

Mice homozygous for the autosomal recessive mutation "viable motheaten" (mev) are severely immunodeficient, show polyclonal B-cell activation, and express multiple autoantibodies over a maximum life span of 25 weeks. Lymphoid tissues from these mice contain large numbers of atypical plasma cells in which discrete glycoprotein inclusions are found within the endoplasmic reticulum. Such plasma cells are termed "Mott cells," and the inclusions are called "Russell bodies." Dense accumulations of Mott cells are present in the marginal zones of the spleen and in the lymph nodes of mev/mev mice. Russell bodies in Mott cells from mev/mev mice contain immunoglobulin (Ig) as shown by immunofluorescence microscopy at the light-microscopic level and by indirect protein A-immunogold localization at the electron-microscopic level. Ultrastructural analyses reveal the presence of amorphous, lamellar, and crystalline Russell bodies. These Ig crystals have a periodicity of 150-190 A. Lymph node cell preparations which were enriched in Mott cells by velocity sedimentation failed to secrete Ig in a polyclonal reverse plaque assay. An obligate role of the thymus in Mott cell development is evidenced by the absence of Mott cells in neonatally thymectomized mev/mev mice and in mice doubly homozygous for the nude (nu) and mev mutations. These data suggest that Mott cells in mev/mev mice are thymic-dependent plasmacytoid cells resulting from chronic B-cell activation accompanied by impaired Ig secretion.

Age Factors↗
PubMed1987

[Value of RU 486 in failed terminations of pregnancy].

One of the complications of therapeutic termination of pregnancy is the complete retention of the embryo. The authors present four cases of repeated failure to evacuate the uterus associated with multiple fibroids or a malformation of the uterus. The use of RU 486 to soften the cervix and to allow it to dilate spontaneously made it possible in each case to aspirate the products completely. This action on the cervix of RU 486 could be used to make it easier to terminate early pregnancies up to the 12th week and particularly when there is associated uterine pathology.

Abortifacient Agents↗
PubMed1987

Studies of instrumental behavior with sexual reinforcement in male rats (Rattus norvegicus): I. Control by brief visual stimuli paired with a receptive female.

We describe a novel procedure for measuring instrumental sexual behavior in the male rat by using a second-order schedule of presentation of sexual reinforcement, an estrous female. Experimental assessment and validation of the paradigm have been achieved by examining (a) the importance of the conditioned stimulus in maintaining instrumental responding by measuring the effects of its omission during a test session, (b) the effects and motivational specificity on instrumental behavior of the postejaculatory refractory period (a period of sexual unarousability) and of satiety for food by measuring the impact of each manipulation on animals working for food and for a female, (c) the effects of replacing an estrous female with an anestrous one as the earned reward, and (d) the correlations between conditioned and unconditioned measures of sexual behavior. We conclude that the second-order paradigm provides a means of distinguishing between the effects of neuroendocrine manipulations on incentive motivational and performance variables underlying the expression of sexual behavior.

Animals↗
PubMed1986

Extrarenal rhabdoid sarcoma.

Rhabdoid sarcoma is a tumor of unknown etiology that usually occurs in the kidneys of infants and small children. We report an adolescent with a rhabdoid sarcoma of the chest wall. In addition to the patient's age and the site of the tumor, other unusual features of this case were as follows: positive staining of tumor cells with neuron-specific enolase, the presence of chronic, active, hepatitis that apparently developed coincident with the sarcoma, and the presence of widespread hemosiderosis. Two of the patient's siblings died in infancy with degenerative neurologic disease, hepatomegaly, and multiple congenital anomalies. The histochemical findings and family history lend support to previous suggestions that some rhabdoid sarcomas may be of neural crest origin and may be heritable lesions.

Adolescent↗
PubMed1986

3-Deazauridine (NSC 126849): an interesting modulator of biochemical response.

3-Deazauridine (NSC 126849) is a structural analog of uridine that inhibits the biosynthesis of Cytidine-5'-Triphosphate by competitive inhibition of Cytidine Triphosphate synthetase which is considered to be the primary mode of action of this nucleoside analog. Despite a paucity of clinical attention given to this drug as a single agent, it has generated much enthusiasm as a biological response modulator because of its synergistic effect with a number of antitumor agents including Cytosine Arabinoside, 5-aza-2'-deoxycytidine, 5-azacytidine, thymidine and D-galactosamine, although only the cytosine arabinoside/3-Deazauridine combination has been explored clinically. In this paper, the current status of the drug and future perspectives will be discussed.

3-Deazauridine↗
PubMed1986

Stiffness and force in activated frog skeletal muscle fibers.

Single fibers, isolated intact from frog skeletal muscles, were held firmly very near to each end by stiff metal clasps fastened to the tendons. The fibers were then placed horizontally between two steel hooks inserted in eyelets of the tendon clasps. One hook was attached to a capacitance gauge force transducer (resonance frequency up to approximately 50 kHz) and the other was attached to a moving-coil length changer. This allowed us to impose small, rapid releases (complete in less than 0.15 ms) and high frequency oscillations (up to 13 kHz) to one end of a resting or contracting fiber and measure the consequences at the other end with fast time resolution at 4 to 6 degrees C. The stiffness of short fibers (1.8-2.6 mm) was determined directly from the ratio of force to length variations produced by the length changer. The resonance frequency of short fibers was so high (approximately 40 kHz) that intrinsic oscillations were not detectably excited. The stiffness of long fibers, on the other hand, was calculated from measurement of the mechanical resonance frequency of a fiber. Using both short and long fibers, we measured the sinusoids of force at one end of a contracting fiber that were produced by relatively small sinusoidal length changes at the other end. The amplitudes of the sinusoidal length changes were small compared with the size of step changes that produce nonlinear force-extension relations. The sinusoids of force from long fibers changed amplitude and shifted phase with changes in oscillation frequency in a manner expected of a transmission line composed of mass, compliance, and viscosity, similar to that modelled by (Ford, L. E., A. F. Huxley, and R. M. Simmons, 1981, J. Physiol. (Lond.), 311:219-249). A rapid release during the plateau of tetanic tension in short fibers caused a fall in force and stiffness, a relative change in stiffness that putatively was much smaller than that of force. Our results are, for the most part, consistent with the cross-bridge model of force generation proposed by Huxley, A. F., and R. M. Simmons (1971, Nature (Lond.), 213:533-538). However, stiffness in short fibers developed markedly faster than force during the tetanus rise. Thus our findings show the presence of one or more noteworthy cross-bridge states at the onset and during the rise of active tension towards a plateau in that attachment apparently is followed by a relatively long delay before force generation occurs. A set of equations is given in the Appendix that describes the frequency dependence of the applied sinusoid and its response. This model predicts that frequency dependent changes can be used as a measure of a change in stiffness.

Animals↗
PubMed1986

A randomized double-blind study of atenolol and celiprolol in mild to moderate hypertension.

The antihypertensive effects of equivalent beta-blocking doses of atenolol and celiprolol were compared in 55 patients with mild to moderate hypertension. Patients with diastolic blood pressure between 95 and 114 mm Hg were randomized to celiprolol or atenolol once daily. The dose of each agent was titrated from 50 to 100 mg atenolol or from 200 to 400 mg celiprolol if the supine diastolic blood pressure remained greater than 90 mm Hg after 2 to 4 weeks treatment at 24 h following dosing. Following titration patients were maintained at constant dosage for 12 weeks. The average reductions in blood pressure over the period of double-blind therapy were similar; for atenolol -17/-16 mm Hg and for celiprolol -14/-13 mm Hg. Therapeutic success rate (percentage of patients with diastolic blood pressure less than 90 mm Hg or reduction in diastolic blood pressure greater than 10 mm Hg), based on the mean over the maintenance period, was 71% and 59%, respectively. Adverse events were minor and similar for both therapies. Once daily atenolol and celiprolol appeared similar in efficacy and safety in mild to moderate hypertension.

Adrenergic beta-Antagonists↗
PubMed1986

Decreased muscarinic acetylcholine receptor number in the central nervous system of the tottering (tg/tg) mouse.

The tottering mouse (tg/tg) is a single-locus mutant, phenotypically characterized by the development of epilepsy associated with distinct electroencephalographic abnormalities. Because of reported alterations in muscarinic receptor (mAChR) number in various seizure states, mAChR density was examined in discrete brain regions of tottering (tg/tg) and coisogenic wild-type (+/+) mice. Saturation binding experiments revealed a widespread decrease in membrane mAChR density in the CNS of adult tottering (tg/tg) mice as compared with age-matched control wild-type (+/+) mice. The decrease was most pronounced in the hippocampus, where tg/tg mice exhibited a 40-60% reduction in mAChR density with no change in the affinity of the receptor for antagonists or agonists. At postnatal day 10, before the reported onset of electroencephalographic abnormalities, 114 and 65% increases in mAChR density were observed in the tg/tg hippocampus and cortex, respectively. Following the development of seizure activity at postnatal day 22, mAChR density in the tg/tg hippocampus was reduced by 29%. No change in brain mAChR density was seen in adult heterozygotes (+/tg), which do not develop electroencephalographic or seizure abnormalities. These results indicate that the development of reduced mAChR number in the CNS of the tg/tg mouse is secondary to abnormal neuronal activity, providing further support for the hypothesis that membrane depolarization can cause a decrease in neuronal mAChR density.

Aging↗
PubMed1986

Computed tomography in the diagnosis of cochlear otosclerosis.

Twelve patients with surgically proven otosclerosis and sensorineural hearing loss were studied with high-resolution computed tomography (CT). The purpose was to identify abnormal bony changes that could be diagnostic of cochlear otosclerosis. Of the 24 temporal bones thus studied, 10 showed positive findings. The findings in our study--as well as those of others--show a pericochlear zone of radiolucency. The precise origin of this is undetermined.

Bone Conduction↗
PubMed1986

Monoclonal antibody specific for the T-tubule of skeletal muscle.

Monoclonal antibodies were raised against a triad-enriched (sarcoplasmic reticulum-T-tubule complex) microsomal membrane fraction of rabbit skeletal muscle. The avidin-biotin complex (ABC) immunoperoxidase staining method was used to screen hybrid colonies. Positive antibodies exhibited a granular doublet pattern at the A-I junction, consistent with the location of triads in rabbit muscle. One monoclonal antibody, M171, was further characterized by ultrastructural and immunoadsorption techniques. Postembedding electron immunocytochemistry was performed on tissue sections embedded in Lowicryl K4M. Goat anti-mouse immunoglobulin absorbed to 10 nm colloidal gold particles was used as an ultrastructural label. In these studies, M171 recognized an epitope at the triads and at periodic openings along the plasmalemma. Immunoadsorption on protein transfers of isolated sarcoplasmic reticulum, surface membrane (plasmalemma and T-tubule), and triad-enriched fractions showed that M171 reacts with a surface membrane component. Taken together, these studies suggest that M171 recognizes an epitope associated with the T-tubule at the triad and at the "mouth" of the T-system at the plasmalemma.

Adsorption↗
PubMed1986

Real and virtual features in texture perception.

The texton theory of preattentive texture perception was recently adopted over a prior model based on the global computation of dipole statistics. It is shown here that the dipole model remains a necessary adjunct unless the texton theory is modified to distinguish real from virtual features of texture perception.

Attention↗
PubMed1986

Inhibition of vascularization in rabbit corneas by heparin: cortisone pellets.

The purpose of this work was to study the effectiveness of heparin plus cortisone, and of cortisone alone in control of corneal vascularization in rabbit eyes. Corneal vascularization was induced by de-epithelialization of the cornea and limbus and part of the bulbar conjunctiva with concurrent trephination and excision of a central 2-mm diameter corneal button. Inhibition of vascularization by polymer pellets impregnated with heparin (Panheprin, Abbott Laboratories; Chicago, IL) and cortisone, or neither drug was studied by implanting the pellets into the eyes at the time of injury and following the eye clinically and histologically. Wounded corneas with empty pellets developed vascularization extending from the limbus to the central cornea within 3 wk (n = 10). In other wounded eyes, heparin:cortisone pellets prevented vascularization (n = 10) while cortisone pellets slowed, but did not totally inhibit vascularization (n = 6). In other eyes, clear autografts were transplanted into vascularized eyes; and the ability of the drug-impregnated pellets to inhibit grafts vascularization was evaluated. In eyes with heparin:cortisone pellets inserted into the donor button at the time of keratoplasty, the autografts remained clear for at least 6 wk (n = 10) but subsequently vascularized if the sutures were not removed, while cortisone pellets slowed but did not block vascularization (n = 6). If heparin:cortisone pellets were inserted into the vascularized host tissue, rather than into the donor button, vascularization of the graft occurred (n = 6). Thus, heparin (Panheprin, Abbott Laboratories; Chicago IL) plus cortisone inhibited vascularization in rabbit cornea in the models studied: The effect of other commercially available heparins remains to be studied.

Animals↗
PubMed1986

Intracellular localization and serological identification of a HSV-2 protein in cervical cancer.

Exfoliated atypical cells from US and Italian patients with cervical intraepithelial neoplasia or invasive cancer stained in indirect immunofluorescence with a monoclonal antibody to a high MW HSV-2 protein (ICP10). The proportion of staining cells increased as a function of the severity of the cervical anaplasia. In the majority of cases with mild or moderate dysplasia staining was restricted to the cytoplasm while atypical cells from 6 of 7 cases with marked dysplasia and 7 of 7 cases with invasive cancer evidenced also nuclear staining. Normal exfoliated cells did not stain even when obtained from tissue adjacent to the tumor mass. Patients with ICP10 positive atypical cells had antibody to ICP10 as determined by the Western blot assay. Serologic analyses indicated that there was a good correlation between: (i) the Western blot and the CF assay previously used to detect antibody to AG-4 (Aurelian, et al, Cancer, 48, 455, 1981) and (ii) cervical anaplasia and ICP10 seropositivity. A similar correlation with cervical anaplasia was not observed with respect to antibody to two other viral proteins (ICP12/14 and 68K).

Antibodies, Monoclonal↗