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Biomedical subjects

J Bard

Publications and source records attributed to J Bard.

At least 91 records · Page 5Linked to original sources
PubMed1982

[Regression of the cerebellar syndrome under long-term administration of 5-HTP or the combination of 5-HTP and benserazide. 26 cases quantified and treated using computer methods].

A quantitative evaluation of cerebellar ataxia, with an ataxia score (total, static, kinetic) and the measurement of objective values related to the major symptoms, is proposed. 21 patients with heredo-ataxias were treated for 12 months with high doses (16 mg/kg/day) of D-L-5-HTP, L-5-HTP or the association D-L-5-HTP (16 mg/kg/day)-Benserazide(6 mg/kg/day). A computerized processing of the data obtained by regular examination was performed. The ataxia showed a significant regression at the 12th month, mainly in the static performances and in the speed of speech. L-5-HTP appeared to be more active than D-L-5-HTP. The regression of the cerebellar ataxia was also observed in non degenerative conditions such as multiple sclerosis and surgical injury of the anterior lobe vermis, showing that 5-HTP was active on the cerebellar syndrome in general. The regression of the cerebellar ataxia was very slow in inherited diseases and continued for 2 or 4 months after the treatment stopped. A serotoninergic cerebellar control of motricity is discussed.

5-Hydroxytryptophan↗
PubMed1981

T cell development. Precursors and inducer requirements of helper effector and feedback suppression inducer cell sets.

The surface phenotypes and differentiative history of specific helper-effector (HE) and specific feedback suppression-inducer (FBSI) cell sets were further defined in reference to the Qa-1 and I-J marker systems by culture of selected sets of cortisone-resistant nylon-purified thymocytes with antigen on primed macrophages. The generation of Ly-1:HE and Ly-1:FBSI cell sets required, in each case, two initiating sets: a precursor set and a differentiation-inducing set. Precursor sets were distinguished from inducer sets by genetic markers. Accordingly, HE cells, phenotype Ly-1:Qa-1-:I-J-, differentiated from Ly-123:Qa-1- cells in the presence of Ly-1:Qa-1+:I-J+ inducer cells; and FBSI cells, phenotype Ly-1:Qa-1+:I-J+, differentiated from Ly-123:Qa-1- in the presence of Ly-1:Qa-1+:I-J+ inducer cells. The Ly-123:Qa-1-precursors of HE and FBSI cells have been distinguished from one another previously but there is as yet no evidence whether differentiation of these precursor sets requires the same or different Ly-1:Qa-1+:I-J+ inducer sets.

Animals↗
PubMed1981

Cellular basis for the loss of carcinogen from methylcholanthrene-impregnated Millipore membrane.

Millipore 'discs' impregnated with methylcholanthrene dissolved in wax or in crystalline form implanted subcutaneously in mice evoke an early intense macrophage and giant cell reaction; later the discs become covered with connective tissue, and eventually fibrosarcomas develop in their vicinity. Studies with tritium-labelled material show that under these conditions methylcholanthrene (MC) is removed from the discs and broken down rapidly (half life about 7 days) to a water-soluble product, which diffuses locally, is distributed widely via the blood stream, and is excreted in faeces and urine. Removal of label is halted by whole-body irradiation (550 R) with the disc area shielded; this observation, in conjunction with the histological and autoradiographic findings and the paucity of label in cells stripped from excised discs, points to the conclusion that the removal of MC from impregnated discs, and its subsequent degradation, depend on the presence of macrophages and the continual replacement of spent macrophages by new cells generated centrally. The rate of disappearance of label from implanted [3H]MC discs was not altered by administration of Corynebacterium parvum; this, however, does not exclude the possibility that the metabolic pathways involved in the removal of MC are altered. To investigate this it is proposed to study, in both normal mice and mice treated with C. parvum, the extent to which cytochrome P450 and other enzymes concerned in the activation and detoxification of polycyclic hydrocarbons by liver microsomal fractions are inducible in the macrophages that accumulate in inflammatory exudates. This histological techniques used should be readily applicable to the study of the early stages of chemical carcinogenesis and the host reaction to transformed cells.

Animals↗
PubMed1981

[Short-latency somatosensory evoked potentials (SEPs) in dyssynergia cerebellaris myoclonica (author's transl)].

Short-latency SEPs following stimulation of the median nerve at the wrist have been studied in 6 patients suffering from dyssynergia cerebellaris myoclonica (DCM). Cervical N14 and scalp-recorded P15 potentials were found to be normal in patients with appropriate recording conditions. The N20 potential, usually recorded in normals in the parietal region contralateral to the stimulated side, was recorded only in 3 cases out of 6. When present, the N20 potential was found to be normal in latency, amplitude and topography. These data suggest that the electrophysiological events related with information processing at the subcortical levels of the lemniscal pathways (N14, P15) are unmodified in DCM, and lend substance to the hypothesis of a cortical long-loop reflex responsible for the triggering of intention myoclonus in these patients.

Adult↗
PubMed1981

Distinctive urinary odors governed by the major histocompatibility locus of the mouse.

It has been shown that major histocompatibility complex (MHC) types affect the mating choices of mice and that mice can be trained to distinguish arms of a Y maze scented by odors from MHC-congeneic mice. It is now shown that sensory discrimination of MHC types by trained mice in the Y maze is equally effective with urine as the source of odors. Trained mice, male and female, successfully distinguished between urines of MHC-dissimilar F2 segregants of an MHC-congeneic cross but not between urines of MHC-identical F2 segregants. In a control study with a transfer of training procedure, in which reward was withheld to eliminate any basis for new learning, the trained mice successfully distinguished between urines from panels of MHC-congeneic inbred and F2 segregant congeneic mice that had not previously been used as urine donors. Thus urine, which is a source of chemosensory signals in many species, is also a potent source of the MHC-determined odors that distinguish individual mice.

Animals↗
PubMed1980

Developmental and communicative interrelations of Ly123 and Ly1 cell sets.

To distinguish and define the differentiative and communicative relations of Ly123 and Ly1 cells in generating specific helper-effector (HE) (Ly1:HE) and specific suppression-inducing (SI) (Ly1:SI) cells, these two functional sets were generated from various combinations of congenic genetically marked sets of cortisone-resistant nylon-purified thymocytes (CRNPT) by culture on antigen-primed macrophages (M phi) (the (T-M phi culture system). It was thus shown that Ly1:HE and Ly1:SI cells are produced by differentiation from antecedent Ly123 cells. Ly1:HE and Ly1:SI are separate Ly1 populations; generationof Ly1:HE cells requires the presence of Ly1 cells, whereas the generation of Ly1:SI cells does not. Although the Ly23 CRNPT set, which is included when Ly123 cells are positively selected with Lty-2 antiserum is ruled out as a precursor source of Ly1:SI cells, the possibility of a communicative role for Ly23 cells in generating Ly1:SI cells remains to be investigated. The role of the Ly1 set required for the generation of Ly1:HE cells from CRNPT is communicative, not differential; and it is not a precursor source of Ly1:HE or Ly1:SI cells in the CRNPT population. It remains to be seen whether the use of additional phenotypic markers will distinguish subsets of Ly123 and Ly1 cells engaged in these several functions.

Animals↗
PubMed1980

Feedback suppression: phenotypes of T cell subsets involved in the Ly1 T cell-induced immunoregulatory circuit.

Ly1 inducer t cells (Ly1:SI) activate resting T cells to generate potent suppressor activity. Primed Ly1:SI generated in vitro were assayed for suppression induction in cultures containing B cells and various Lyt T cell sets that had been positively and/or negatively selected using alpha Lyt sera. These experiments both reaffirm the previously reported requirement for an Ly123 T cell in suppression by Ly1:SI and implicate a third T cell subset, which is absolutely required for the full expression of Ly1:SI-induced feedback suppression. This subset of T cells has the cell surface phenotype, Ly1- Ly23+ 1J+ Qa-1-.

Animals↗
PubMed1979

Recognition among mice. Evidence from the use of a Y-maze differentially scented by congenic mice of different major histocompatibility types.

Previous studies of mating preference signified that mice can sense one another's major histocompatibility complex (MHC) types, probably by olfaction. This conclusion has now been substantiated by the use of a Y-maze whose two arms were differentially scented with currents of air conducted through boxes occupied by B6 (H-2b) males and by B6-H-2k congenic males. Four B6 mice, two males and two females, were successfully trained, by water deprivation and reward, to enter the arm scented by B6 or B6-H-2k males. One of the males and one of the females were trained to select the B6-scented arm; the other male and female were trained to select the B6-H-2k-scented arm. Untrained mice showed no MHC discrimination in the maze. The performance of the trained mice in distinguishing between MHC congenic homozygous F2 segregants derived from a cross of B6-H-2k with B6 was as good as their performance in distinguishing the respective inbred strains, thus essentially eliminating alternative and significant additional explanations of MHC-associated sensory discrimination. The data further indicate that chemosensory discrimination of MHC types can be entirely dissociated from sex differences and from the circumstances of mating.

Animal Communication↗