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Biomedical subjects

B Blum

Publications and source records attributed to B Blum.

At least 55 records · Page 3Linked to original sources
PubMed1989

Depressor effects of muscarinic and non-muscarinic mediation induced by lateral hypothalamic stimulation in the cat.

Transient sympathetically-mediated depressor effects were induced by stimulation of a small locus in the lateral hypothalamic peri-fornical region, medial to the fields of Forel. The ganglionic blocking agent, atropine methyl nitrate (ATMN), was used to show that muscarinic as well as non-muscarinic sympathetic ganglion receptor neurotransmission was involved. Evidence is presented that stimulation of this LH site co-activates a number of mechanisms and that depending on which of these are activated, the ganglionic blocking agent ATMN may either block, reverse or potentiate the depressor effect.

Animals↗
PubMed1989

Functional and molecular characterization of a monoclonal antibody against the 165-186 peptide of human IL-1 beta.

A synthetic peptide of human recombinant interleukin 1 beta (hrIL-1 beta) 165-186, which exhibits biological activity in the human fibroblast assay, was used as an immunizing antigen to obtain a murine monoclonal antibody (MoAb) termed FIB 1. This MoAb, an IgG1, reacts specifically with hrIL-1 beta, but not with hrIL-1 alpha, as measured in enzyme-linked immunosorbent assays (ELISA). The MoAb FIB 1 detects the characteristic 17 kDa IL-1 protein in Western blots. Binding to the antigen is specific, as deduced also from the close correlation of ELISA immunoreactivity with IL-1 biological activity. The anti-IL-1 beta 165-186 Ab specifically neutralizes the biological activity of hrIL-1 beta and native IL-1, as measured by the IL-1-induced proliferation of murine thymocytes and human fibroblasts and the IL-1-dependent IL-2 production by murine T cells (EL4-6.1). Fifty per cent of hrIL-1 beta activity (25 U/ml, or 0.25 ng/ml) has neutralized by less than 30 micrograms/ml of MoAb. Furthermore, FIB 1 recognizes intracellular IL-1 in lipopolysaccharide-stimulated human peripheral blood mononuclear cells. The anti-IL-1 beta 165-186 Ab does not react with the shorter IL-1 beta fragment 161-173 in solid-phase ELISA, therefore the binding region seems to be localized in the amino acid sequence VALGLKEKNLYLS. A sandwich-ELISA, using a polyclonal sheep anti-IL-1 beta 251-269 Ab as the capture antibody and an anti-IL-1 beta 165-186 MoAb as the detecting probe, allowed the determination of IL-1 beta from crude culture supernatants.

Animals↗
PubMed1989

Inferior parietal lobule neurones related to eye and hand reach movements in rhesus monkey.

Analysis was made on neuronal responses of the inferior parietal lobule to visual, jump, or 'reach' behavioral paradigm in 2 awake, trained rhesus monkeys. Preconditioning and antidromic electrical stimulation of medial and oral pulvinar LP nuclei and the arcuate gyrus aided the study. The results reveal two reach cell categories: one with no definable visual sensitivity (NVHRN) and one with visual receptive field responsiveness (VHRN). The VHRN reach cell firing is characterized by an early component. As the latter was observed only when the monkey reached loci inside but not outside of the cell-receptive field, it was equated with the cell visual receptive field response. This component could be voided by preconditioning stimulation of medial pulvinar or LP, the latencies of the VHRN responses becoming longer and comparable to NVHRN. If the consequences of reaching were nulled in any of a few different ways, such as preventing the monkey from reaching, disenabling the panel key, or denying the reward, a reach cell biphasic firing response showed no change in the first burst, but the second burst was absent, suggesting the latter's relation to satiation. If a jump cell's visual responses enhanced by the 'jump' paradigm were negated by preconditioning stimulation, the saccadic eye movement that otherwise followed the enhanced signals was replaced by another saccade, different in direction and amplitude, as if of other frames of reference. It seems, therefore, that the inferior parietal lobe system subserves in two types of reach behaviour: one with and one without visual guidance, playing perhaps a role in selecting strategies such as the dynamic option to do away with the visual guidance, if circumstances demand.

Animals↗
PubMed1987

Sympatho-inhibitory mechanisms acting at sympathetic ganglia to attenuate hypothalamic-induced pressor effect in the cat.

Pressor and tachycardic effects induced in the cat by stimulation of a lateral hypothalamic (LH) site, are shown to be mediated by sympathetic ganglia nicotinic receptor, and potentiated under atropine methyl nitrate sympathetic ganglia blockage. It is postulated that a sympatho-inhibitory pathway muscarinic ganglionic mechanism, co-activated by the LH stimulation, attenuates the pressor and tachycardic effects, the potentiation presumably being a manifestation of blockage of that mechanism.

Animals↗
PubMed1987

A vocabulary for medical informatics.

The terminology in medical informatics is evolving rapidly. The organizers of MEDINFO and SCAMC have used different sets of keywords to index their documents. Recognizing the limitations of this approach, members of those organizations joined with the National Library of Medicine in the creation of a better terminology for medical informatics. A hierarchical structure was placed on the terms to produce a thesaurus typical of the sort often used in the indexing and retrieving of documents. The building of this thesaurus began with an automatic merging of the thesaurus used by the Association of Computing Machinery and the Information Sciences component of the "Medical Subject Headings." This product was pruned by eliminating terms not related to those in the MEDINFO keyword list or not in the medical informatics literature. Further refinement of the thesaurus resulted from extensive discussions among the authors of this paper. The first major application of this terminology has been to the indexing of the articles in "MEDINFO-86 Proceedings." Major components of this medical informatics thesaurus also have been incorporated into the "Medical Subject Headings." This paper describes the process of preparing the thesaurus and presents an evaluation of its coverage of the "MEDINFO-86 Proceedings."

Abstracting and Indexing↗
PubMed1986

Processing in the external transcribed spacer of ribosomal RNA from Physarum polycephalum.

The rDNA of the myxomycete Physarum polycephalum is transcribed to give a 13.3 kb precursor of ribosomal RNA. At 1.7 kb downstream of the primary initiation site there is a processing site or a second initiation site. This site was studied by S1-mapping, DNA sequencing and electron microscopy. None of these methods could conclusively distinguish between the two formal possibilities. However, capping experiments indicate that rapid processing is taking place at this site rather than reinitiation. In addition, primary transcripts and processed molecules were assayed throughout the synchronous mitotic cycle. During all interphase stages newly initiated transcripts of rDNA and products of the first processing step are present in similar amounts, indicating control of initiation and not of maturation as being the main regulatory step for the accumulation of mature rRNAs. During the brief period of mitosis the level of newly initiated rRNA precursors is lowered.

Base Sequence↗
PubMed1986

Tubulin mRNAs of Trypanosoma brucei.

The tubulin genes of Trypanosoma brucei are located in a single, tightly packed cluster of ten tandemly arranged alternating alpha and beta-genes. No tubulin genes are detected outside the clustered array. Therefore, the cluster can be assumed to be the locus of tubulin gene expression. Single bands of alpha and beta-tubulin mRNAs are observed in cultured procyclic as well as in bloodstream trypanosomes. Both alpha and beta-tubulin mRNAs have distinct 5' termini, which carry a 35-nucleotide mini-exon sequence. The 3' termini of both mRNA populations are heterogeneous.

Animals↗
PubMed1986

[Traumatic pneumatocele--a case report].

The posttraumatic pneumatocele is a rare intrapulmonary lesion following blunt thoracic injury. By means of a well documented case report this rare form of lung contusion is demonstrated and the clinically important differential diagnosis is discussed.

Adult↗
PubMed1985

Enhancement of visual responses of area 7 neurons by electrical pre-conditioning stimulation of LP-pulvinar nuclei of the monkey.

The characteristics of visually evoked unit responses in area PG of the infraparietal lobule were studied in the awake trained Rhesus monkey. These responses are shown to be significantly modified by pairing the visual stimulus with pre-conditioning stimulation of targets in the LP Pulvinar complex. Pre-conditioning stimuli were either single pulses, or a 50 ms train of pulses at 100 Hz delivered through bipolar electrodes 20 ms prior to, simultaneously with, or 50 ms following the visual stimulus. In some cases, modifications of the visual responses appeared as more massive discharges; in others they became bursts of constant latencies, pattern and duration, that contained high frequency discharges. A pre-conditioning single stimulus delivered simultaneously to a few sites in the LP, medial and lateral pulvinar was more effective than stimulation at a single electrode site, and produced an enhancement that appeared like an additive effect of several inputs. In the enhanced condition, repetition of single pulse preconditioning stimulation resulted in a considerable build-up of the enhancement. A pre-conditioning train of stimuli delivered during enhancement resulted in a further increase in the constancy of response durations and patterns. These changes, lasting as long as five minutes, manifested hysteresis: when recovery was allowed without any pre-conditioning stimulation, the various response patterns appeared in a reverse order. It is proposed that this dependence of the responses on the neural state is based on a complex network of inputs to cells of area 7.

Animals↗
PubMed1984

Specific and non-specific inhibition induced by LP-pulvinar inputs to area 7 of the rhesus monkey.

Evidence is presented that inputs from the LP and/or medial or lateral pulvinar nuclei to area 7 neurons may induce not only previously reported enhancement effects but also an assortment of inhibitory effects. Among the latter, both nonspecific and highly specific inhibitions were observed. The high order nature of the network under consideration is reflected by the great variety of types of inhibition observed: non specific general and also specific types of inhibition. Among the specific types preferential inhibition was observed in which the visually evoked but not the spontaneous discharges were affected. In another highly specific type of inhibition, there is cancellation of an added value to the visual response by a cognitive component of the stimulus, a type termed negation. The large variety of interactions observed is interpreted on the basis of massive and varied converging inputs to these cells from the above-mentioned brain regions. An hypothesis is proposed on the basis of these data that the posterior parietal neurons respond to visual stimuli in a way that is uniquely modifiable by a large variety of other added stimuli related to behavioral parameters of the situation and to the various grades of complexity of the visual stimulus. It is assumed that interaction of interneurons of a variety of types is responsible for this large repertoire of processing capacity.

Animals↗
PubMed1983

Oxytocin antagonism of hypothalamic-induced angina-like ECG changes and pressor effects in the cat.

Electrical stimulation of a specific site in the lateral hypothalamus of the cat, in a region posterior to Hess' defense area, results in pressor effects and angina-like ECG changes which consist either of T-wave inversion and ST-segment prolongation or in the appearance of tall T-waves. Oxytocin (10 U, i.v.) administered 15 min prior to stimulation, prevents the former ECG changes and BP rise in 90%, and the latter ECG changes and BP rise in 50% of the animals.

Angina Pectoris↗
PubMed1983

Localization and DNA sequence around the initiation site of ribosomal RNA transcription in Physarum polycephalum.

We have used S1 nuclease to map the initiation site of ribosomal RNA transcription in the acellular slime mold Physarum polycephalum, and we have determined the sequence of 1011 nucleotides surrounding the start site. Consistent with others' observations, there is little homology with the comparable region of other species. As predicted by previous restriction mapping, direct repeats roughly 30 base pairs in length are present upstream of the initiation site and a 148 base pair duplication occurs in the external transcribed spacer. The results also suggest the presence of a processing site within the external transcribed spacer of the ribosomal transcription unit.

Base Composition↗
PubMed1983

A pharmacological analysis of autonomic pathways mediating myocardial disturbances originating in a lateral hypothalamic area of the cat.

A study was made of the mechanisms mediating autonomic changes resulting from stimulation of a site in the lateral hypothalamic area (LHA). This site, when stimulated, induced angina-like ECG disturbances similar to those observed in some cases of brain traumas. These ECG changes were often associated with other autonomic changes, such as pressor response, tachycardia (in some cases bradycardia), nictitating membrane (NM) contraction and pupillary dilatation. Most symptoms were sympathetic: they were largely abolished by spinal cord section between C1 and C2, but were not affected by vagotomy, except that bradycardia was converted to tachycardia. Adrenal catecholamines were not involved since adrenal vein ligation was without effect. Hexamethonium (5-10 mg/kg) prevented pressor response and tachycardia in most cats but only partly protected against ECG changes and NM contractions. Atropine methyl nitrate (0.2 mg/kg) abolished the remaining ECG abnormalities and NM tension. The beta-receptor antagonists, propranolol and practolol (50 micrograms/kg) completely prevented the ECG changes induced either by isoprenaline or LHA stimulation. It is concluded that the symptoms induced by LHA stimulation result from noradrenaline release in the target organs.

Angina Pectoris↗
PubMed1983

Stereotaxic head restraint for chronic and semi-chronic marmoset and macaque monkeys.

A device allowing head holding and stereotaxic manipulations in both small-sized Marmoset and in relatively large Macaca monkeys is described. Its design permits free access to most targets in the visual system and optimizes presentation of visual stimuli in awake-chronic and anaesthetized semi-chronic preparations. Extra-aural attachments to temporal bone are implanted stereotaxically, under anaesthesia, on both sides of the skull. This provides means for stereotaxic head-holding which minimizes discomfort to the animal. Maintenance of stereotaxic precision over long periods of time, possibility of realignment and use of one device for various monkey species are special features of the method.

Animals↗