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Biomedical subjects

C Gonzales

Publications and source records attributed to C Gonzales.

At least 55 records · Page 3Linked to original sources
PubMed1991

Heterogeneous distribution of the limbic system-associated membrane protein in the caudate nucleus and substantia nigra of the cat.

The limbic system-associated membrane protein is a glycoprotein selectively associated, in the adult, with dendrites and cell bodies of neurons of the limbic system and related brain regions. In the present study, the distribution of the limbic system-associated membrane protein was studied by immunohistochemistry in the caudate nucleus and substantia nigra of the cat to determine how its expression relates to the compartmentalization of these areas. In all areas of the caudate nucleus, the pattern of limbic system-associated membrane protein immunoreactivity was highly heterogeneous, labeling zones that were in register with areas expressing neurochemical markers that classically identify striosomes. The extrastriosomal matrix exhibited low levels of staining. The results show that the limbic system-associated membrane protein is expressed by neurons within the target areas (striosomes) of subsets of limbic afferents (originating mainly from the basolateral nucleus of the amygdala and the prefrontal cortex), whereas regions of the caudate nucleus (extrastriosomal matrix) receiving inputs from other subdivisions of the limbic system, such as the cingulate cortex and the ventral tegmental area, contain relatively low levels of limbic system-associated membrane protein immunoreactivity. Thus the expression of this antigen may reflect the targeting of specific groups of limbic afferents to regions that are intimately associated with distinct components of the limbic system. The presence of limbic system-associated membrane protein in neurons of the substantia nigra pars compacta does not appear to be related to the presence or absence of the protein in their striatal target areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Afferent Pathways↗
PubMed1991

Differential distribution of somatostatin receptor subtypes in rat brain revealed by newly developed somatostatin analogs.

Somatostatin receptor subtypes were labeled with the somatostatin analogs [125I]CGP 23996 and [125I]MK 678 and the distribution of these receptors in rat brain was investigated using quantitative autoradiographic techniques. [125I]CGP 23996 and [125I]MK 678 specifically label different populations of somatostatin receptors in rat brain. In a number of brain regions striking differences in the distribution of the somatostatin receptor subtypes labeled by each peptide were observed. High levels of binding sites for both [125I]CGP 23996 and [125I]MK 678 were present in the cerebral cortex, CA1 region and subiculum of the hippocampus. In contrast, high levels of [125I]MK 678 binding were found in the dentate gyrus of the hippocampus while few [125I]CGP 23996 binding sites were observed in this brain region. [125I]CGP 23996 binding was detected in the central region of the interpeduncular nucleus whereas the dorsal and lateral subnuclei of this brain area expressed mainly somatostatin receptors with high affinity for MK 678. The locus coeruleus and regions of the superior colliculus and hypothalamus selectively express [125I]MK 678-sensitive somatostatin receptors. Furthermore, limbic structures such as the lateral septum, the nucleus accumbens and ventromedial striatum had much higher levels of [125I]MK 678 binding sites than [125I]CGP 23996 binding sites. Differences in the expression of the somatostatin receptor subtypes were also detected in the substantia nigra. [125I]CGP 23996 binding was present in the pars reticulata but not the pars compacta whereas the reverse distribution for [125I]MK 678 binding sites was observed. The differential distribution of [125I]CGP 23996 and [125I]MK 678 binding sites in rat brain supports the hypothesis that these peptides selectively label different somatostatin receptor subtypes in the central nervous system.

Animals↗
PubMed1991

Ossified mucin-secreting choroid plexus adenoma: case report.

This is the first report of a fully documented case of an ossified mucin-producing benign choroid plexus tumor. This was a chance finding in a man who complained only of posttraumatic low back discomfort. The ossification of the tumor appears to have been therapeutic. Mucin production may be a defense mechanism.

Adenoma↗
PubMed1990

Amygdalonigral pathway: an anterograde study in the rat with Phaseolus vulgaris leucoagglutinin (PHA-L).

The projection from the central nucleus of the amygdala to the substantia nigra was labeled by injections of the anterograde tracer Phaseolus vulgaris leucoagglutinin into different subregions of the nucleus. A sparse projection of labeled bouton-like swellings was observed in the rostral, medial substantia nigra pars compacta and ventral tegmental area from all subregions of the central nucleus of the amygdala that were injected. A dense projection of labeled axons and bouton-like swellings was observed in the lateral part of the substantia nigra pars compacta and pars lateralis when the injection site included the dorsal and rostral central nucleus. Heavy labeling was also seen in the lateral retrorubral field in these cases. In no instances were labeled terminals observed in the substantia nigra pars reticulata. The same pattern of labeling in the lateral substantia nigra and retrorubral field was seen after injections rostral to the central nucleus or dorsal and medial to it in the sublenticular region. The results suggest that the amygdalonigral pathway contributes to the innervation of extensive areas of the substantia nigra pars compacta. The major component of the pathway, however, projects only to a subregion of the substantia nigra. The origin of this pathway is confined to a discrete region of the dorsal central nucleus of the amygdala but extends rostrally into an area that is part of the "extended amygdala."

Amygdala↗
PubMed1990

Ischemic damage in the striatum of adult gerbils: relative sparing of somatostatinergic and cholinergic interneurons contrasts with loss of efferent neurons.

The pattern of ischemia-induced cell death was examined with histochemical methods in the striatum of adult gerbils 4 and 7 days after transient forebrain ischemia. The results showed a massive loss of immunoreactivity to enkephalin and tachykinins, peptides present in striatal efferent neurons. In contrast, neurons expressing acetylcholinesterase activity, or choline acetyltransferase immunoreactivity, as well as neurons immunoreactive for somatostatin, were relatively preserved in areas of severe neuronal loss. The selective vulnerability of subpopulations of striatal neurons to transient ischemia in the adult is similar to that observed in the neonate and after local injections of agonists of N-methyl-D-aspartate receptors, but not of agonists of other glutamate receptor subtypes. It also presents striking similarities to the pattern of neuronal death observed in Huntington's disease. The results further support a role for overstimulation of a subtype of excitatory amino acid receptor in ischemia-induced cell death and show that the selective sparing of subpopulations of striatal interneurons after ischemic injury is not related to immaturity of these neurons but also occurs in the adult.

Acetylcholinesterase↗
PubMed1990

Examination of HTLV-I ELISA-positive leukemia/lymphoma patients by western blotting gave mostly negative or indeterminate reaction.

We used enzyme-linked immunosorbant assay (ELISA) and Western blotting, with "purified" human T-cell leukemia virus I (HTLV-I), to test for HTLV-I antibodies in 2583 plasma samples from 1053 leukemia/lymphoma patients treated at Roswell Park Memorial Institute, mostly between 1972 and 1984, and in 110 sera samples from normal healthy persons. The results demonstrate that ELISA and Western blot assay have limitations for HTLV-I antibody detection in an adult T-cell leukemia/lymphoma (ATL) nonendemic population. This conclusion is based on the many false reactives obtained by ELISA, and weak and indeterminate reaction (mostly p19 band) on Western blotting. All moderate to strongly HTLV-I ELISA-positive samples tested were negative for human immunodeficiency virus (HIV) antibodies. Although 6/27 mycosis fungoides (MF) patients tested gave mostly a weak reaction on HTLV-I ELISA, 3/6 MF patients gave multiple bands (p19, p31, p36, gp46) on Western blotting and three samples from one patient gave the same p31, p36, and gp46 bands. This may suggest involvement of some HTLV-I-related virus in MF. These results also indicate that prevalence of HTLV-I infection in leukemia/lymphoma patients was rare, if it exists at all, since, despite the reactivity of some sera with HTLV-I-suspected antigens, none of the samples satisfy the USPHS criteria for positivity which is based on the detection of antibodies to gag protein p24 and to an env gene product gp46 or gp61/68.

Adolescent↗
PubMed1989

Massive hemothorax and Groshong catheters.

Central vascular access with cannulation of either the subclavian or internal jugular vein is a common procedure in the hospital. Complications are rare, but may be severe. We report a case with a near fatal complication in the form of massive hemothorax 19 days after placement of a Groshong catheter.

Adult↗
PubMed1987

Stabilization of chitin synthetase and purification of chitosomes from several mycelial Mucorales.

Stability of chitin synthetase in cell-free extracts from mycelial fungi was markedly improved by the presence of sucrose in the homogenization media. Breakage of mycelium in sucrose-containing buffer yielded enzyme preparations from which chitosomal chitin synthetase could be purified by a procedure involving ammonium sulfate precipitation, gel filtration and centrifugation in sucrose density gradients. Purified chitosomes catalyzed the synthesis of chitin microfibrils in vitro upon incubation with substrate and activators. Chitosomal chitin synthetase from the filamentous form of M. rouxii was similar to the enzyme from yeast cells, except for the poorer stability and diminished sensitivity to GlcNAc activation of the former.

Centrifugation, Density Gradient↗
PubMed1987

Reactivity of monoclonal antibodies to Rickettsia rickettsii with spotted fever and typhus group rickettsiae.

Analysis of 15 spotted fever group (SFG) and 2 typhus group strains of rickettsiae with a panel of monoclonal antibodies revealed a number of shared and unique epitopes of the 120- and 155-kilodalton surface proteins. All of the SFG strains but neither of the typhus group strains reacted with antibody to the lipopolysaccharidelike antigen of Rickettsia rickettsii; possibly the lipopolysaccharidelike antigen is the common antigen which defines the SFG. North Carolina and Montana strains of R. rickettsii known to differ slightly in virulence for guinea pigs differed in at least one epitope of the 120-kilodalton protein.

Animals↗
PubMed1986

[Alleviation of ocular complications of the hyperviscosity syndrome in Waldenström's macroglobulinemia using plasma exchange].

Two patients presenting ocular complications of hyperviscosity syndrome in Waldenström's macroglobulinemia have been treated by plasmapheresis after inefficiency of immunosuppressive therapy. Plasma exchange seems an useful treatment as shown by clinic and angiographic improvement. In each case improvement of retinopathy was correlated with decrease of serum IgM level and blood viscosity measured by isotopic method. Fluorescein angiography, easily repeated, seems a very good method for following hyperviscosity syndrome in Waldenström's macroglobulinemia.

Aged↗
PubMed1980

[Almitrine per os in the therapy of chronic obstructive bronchopneumopathies].

A double-blind study was conducted to evaluate the effects of almitrine, administered orally as 3.5 mg/kg/day for one month, when compared with placebo in 20 patients with chronic obstructive pneumopathies from smoking, currently in the stage of chronic hypercapnic respiratory insufficiency. Clinical improvement was obtained, with a reduction in dyspnea and a more comfortable respiration. Objective signs of improvement where enhanced adaptation to assisted ventilation (3 cases out of 5), and less secondary infection in the almitrine group (0/10) than the placebo group (4/10). A statistically significant improvement (p less than 0.01) was recorded in blood oxygen and bicarbonates levels, and to a lesser degree, in blood CO2 levels (p less than 0.05) and without any increase in overall ventilation. As tolerance was good (8/10), almitrine appears to occupy a place of choice in the field of respiratory analeptic therapy. Its efficacy and convenience in use for daily practice require confirmation in long-term studies (more than 6 months).

Administration, Oral↗
PubMed1979

Mechanisms responsible for antibody-dependent, cell-mediated cytotoxicity to isolated hepatocytes in chronic active hepatitis.

Lymphocytes from patients with chronic active hepatitis have been found to be cytotoxic for isolated rabbit hepatocytes. Although this reaction has been shown to be of the antibody-dependent type, no autologous serum was added to the assay system and in the present experiments the source of the antibody has been sought. The failure of puromycin to block the reaction argued against a role for antibody synthesised during the culture period, and the demonstration that normal mononuclear cells could become cytotoxic when preincubated in chronic active hepatitis sera was more in favour of the passive acquisition of an antibody from the circulation. Evidence for the existence of free antibody in the sera reacting with hepatocyte surface antigens came from an additional series of experiments in which it was shown that preincubation of hepatocytes in chronic active hepatitis sera rendered them susceptible to damage by normal mononuclear cells. This effect was almost completely abolished by adding a membrane lipoportein fraction of human liver (LSP) to the sera during the preincubation step, suggesting that the LSP contained those antigens on the hepatocyte surface against which the majority of the antibodies were directed.

Animals↗