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Biomedical subjects

M Herrera

Publications and source records attributed to M Herrera.

At least 109 records · Page 6Linked to original sources
PubMed1989

[HLA and disease in Argentina. Serologic and genomic polymorphism].

In this report we discuss the results of the association of chronic active hepatitis (B virus) and coeliac disease with HLA class I and class II antigens, in patients of Latin American Caucasian origin. Evidence is presented showing that the alleles involved differ from those reported in other Caucasian populations of different ethnic background. Differences were observed both at the serology and at the DNA (RFLP) level. The relevance of these findings regarding the clinical implications as well as the molecular mechanisms involved in the associations are discussed.

Argentina↗
PubMed1989

Axonal patterns of disc-shaped cells in the central nucleus of the cat inferior colliculus.

The axonal patterns of disc-shaped cells (Dsc) and their distribution within the central nucleus (Cn) of the inferior colliculus was studied in young cats with the rapid Golgi method. Dsc were subdivided in three main cell varieties according to their axonal branching pattern. The first type possesses local axonal collaterals inside the lamina of origin but also gives collaterals and probably terminals to adjacent lamina. The second variety is characterized by a dense axonal plexus with a restricted zone of arborization. The third axonal pattern is distributed in a radiate fashion. These results demonstrate that Dsc contribute to the intrinsic axonal system of the Cn to a larger degree than previously supposed. Axon terminals of Dsc probably establish axo-dendritic contacts with medium sized Stc which probably establish contacts with neighbouring Dsc. This suggests that reciprocal connections between Dsc and Stc could exist in the Cn.

Animals↗
PubMed1988

DNA polymorphism of the HLA-B35 gene associated to different HLA-C locus alleles.

Peripheral blood leukocyte DNA from 31 donors, previously typed as HLA-B35, was digested with EcoRV and analyzed by Southern transfer and hybridization to an HLA class I probe. Out of 31 HLA-B35 positive (+) individuals, 24 showed a 4.6-kb band, previously associated with the B35 allele by Cohen et al. (Proc Natl Acad Sci USA 80:6289-6292). The HLA-B35 allele has a strong linkage disequilibrium (70%) with the Cw4 allele. All samples having the 4.6-kb band corresponded to HLA-B35+, Cw4+ cells, whereas those lacking the band came from HLA-B35+, Cw4-negative (-) cells. Five HLA-B35-, Cw4+ samples were also studied and none showed the band. An HLA-B locus-specific probe gave a strong hybridization signal to this fragment, whereas an HLA-C locus-specific probe revealed different bands. The results suggest that the 4.6-kb fragment contains the B35 gene. Digestion with other restriction enzymes, located the polymorphic site to the 3' end of the gene. Analysis of 18 additional individuals with other specificities of the "4c" antigenic cluster (HLA-B18, B51, B52 and B53) showed that the EcoRV/4.6 kb-band was also present in 5/5 B52 cells and 4/4 B53 samples.

Alleles↗
PubMed1988

Cytoarchitecture and axonal systems in the commissural nucleus of the inferior colliculus in the albino rat. A Golgi study.

The nucleus commissuralis (Ncom) of the inferior colliculus in the rat is cytoarchitectonically divided in four zones: 1) subpial; 2) plexiform dendritic; 3) central and 4) ventral. Each zone possesses definitory neuronal types. The first three zones are innervated by fibres from the dorsal cortex. These fibres arborizes in varied manner in some cases forming axonal nests. Also vertical fibres from deeper zones of the Ncom contribute to the intrinsic vertical axonal system of the Ncom and innervate these zones, in particular fusiform neurons of the central zone. Fusiform and stellate neurons of the central zone also contribute to this vertical axonal system and to the intrinsic circuitry of the Ncom. Some specific types of the dorsal periaqueductal gray (PAGd) are in close relationship with the Ncom. Fusiform and stellate cells of the PAGd send in variable degree their dendrites and in some cases their axons to the commissural neuropil. In turn transverse and vertical fibres from the Ncom arborize in the upper part of the PAGd. This suggest the existence of discrete cell groups in PAGd in relation with the auditory cellular nuclei of the colliculus.

Animals↗
PubMed1988

Stellate cells and their axonal patterns in the central nucleus of the inferior colliculus of the cat (Felis domesticus).

Stellate cells (Stc) in the central nucleus of the inferior colliculus of the cat are divided according to cell body size and shape, dendritic branching pattern and axonal arborization into large, medium-size and small categories. Each of these were divided in different cell types. Three types of large Stc, six types of medium sized Stc and one type of small Stc were described. All of these cell types differ from each other in their morphological characteristics. Stc contribute to the neuropil organization of the central nucleus with numerous axonal collaterals which differ in their form and extension. Large and medium-sized Stc could be projecting neurons with a system of local axonal collaterals while the small Stc is considered a Golgi II type neuron. The probable synaptic relationships between Stc and disc-shaped neurons as well as between the different types of Stc are described. The mode of this probable synaptic arrangement suggests that another level of organization exist in the central nucleus, superimposed to the anatomically defined fibrodendritic laminae.

Animals↗
PubMed1988

Neuronal relationships between the dorsal periaqueductal nucleus and the inferior colliculus (nucleus commissuralis) in the cat. A Golgi study.

Cell types in the dorsal periaqueductal nucleus (PAGd) were studied with the aid of the rapid Golgi method in young cats. The neurons were subdivided into fusiform and stellate types with several varieties of the latter class according to the final destination of their axons. Fusiform neurons send their axons to the neuropil of the Ncom. In turn these neurons receive descending fibres from the nucleus commissuralis (Ncom) which seem to establish axo-dendritic contacts. Also commissural neurons receive contacts from ascending fibres of the PAGd. On the basis of Golgi material it is concluded that particular neuronal types of the PAGd could establish reciprocal connections with neuronal elements of the ventral part of the Ncom. The present study supports the hypothesis that the PAGd could be subdivided into discrete cell groups according to their afferent and efferent projections.

Animals↗
PubMed1987

Secretion of antimicrobial proteins from the parotid glands of different aged healthy persons.

The secretion of three antimicrobial proteins from the parotid glands of 82 generally healthy men and women, 22 to 81 years in age, was examined. No change was observed in the levels of secretory IgA, but statistically significant, modest elevations (approximately 50 to 100%) of lactoferrin, in both unstimulated and stimulated secretions, and lysozyme, in unstimulated secretions, were detected when results were expressed as mg antimicrobial protein/100 ml saliva. However, these alterations were not observed if data were expressed as mg antimicrobial protein/g total protein. Also, no change was detected in an acinar cell exocrine product, the anionic proline-rich proteins, as reported previously by our laboratory. The data are consistent with a maintenance of protective functions in parotid saliva during aging.

Adult↗
PubMed1987

Inhibition of catecholamine secretion from bovine chromaffin cells by adenine nucleotides and adenosine.

ATP, ADP, and adenosine have been found to inhibit acetylcholine-stimulated secretion from isolated cells of bovine adrenal medulla (chromaffin cells). Maximal inhibition is approximately 30% under the conditions studied; half-maximal inhibition occurs at nucleotide concentration in the micromolar range. Cells must be incubated with ATP for approximately 90 s for maximal inhibition, but inhibition by adenosine occurs much faster, an observation suggesting the possibility that ATP and ADP exert their effect after being converted to adenosine. Experiments with cells preloaded with the fluorescent calcium chelator quin 2 indicate that external ATP can diminish the rise in cytosolic Ca2+ concentration that follows stimulation by acetylcholine.

Adenosine Diphosphate↗
PubMed1987

The commissural nucleus of the inferior colliculus in the rabbit. A morphological study.

The present study describes the essential neuron and axon typology in the nucleus commissuralis of the rabbit inferior colliculus. Cytoarchitectonically, the nucleus is divided in five cellular zones: 1) subpial; 2) plexiform dendritic, 3) central; 4) ventral and 5) periaqueductal zone this latter surrounding the commissural neuropil. Each zone possess particular neuronal types which were described according to its dendritic pattern. In addition, three axonal systems each oriented in a different plane of the commissure of the inferior colliculus were described. Each system possess particular axonal arborizations. Of particular interest is the arrangement of vertical fibres and dendrites in the central zone where they form dendrite and axonal bundles.

Animals↗
PubMed1987

[Pediatric AIDS through vertical transmission].

We report here the first paediatric immunodeficiency acquired syndrome (AIDS) in Spain, acquired by vertical-transmission and a second infant case with the same transmission and classified as AIDS related complex. We also mention the incidence and characteristics, of the neonatal population born in the last eighteen months to HIV positive mothers in our geographic area. The AIDS patients, was a female drug addicted parents born to who died at 22 month. Her parents are HIV positive and have ARC. The second patient was a boy, born to a sexual HIV positive partner of a member of a high risk group who died pat 17 month. Review of the literature until September 1986, revealed 369 AIDS paediatric patients, the number is lower 265 (7 Spanish), if only vertical transmitted AIDS is considered. For this reason, we considered pertinent to provide some information about clinical manifestations and laboratory, radiologic and necropsy findings in our patients.

AIDS-Related Complex↗
PubMed1985

Mouth occlusion pressure (P0.1) in acute respiratory failure.

We studied 20 unselected patients admitted to our Intensive Care Unit (ICU) suffering from acute respiratory failure (ARF), who needed mechanical ventilatory support. In all of them we followed a prospective protocol to investigate the value of mouth occlusion pressure (P0.1) as an indicator for weaning. Fifty-two tests were classified into three groups: a need to be reconnected to mechanical ventilation (MV), stable on intermittent mandatory ventilation (IMV), or spontaneous breathing on a T-tube (TT). The results showed that at increased values of P0.1 there were more difficulties in weaning patients from MV. Seventy-eight percent (78%) of the occasions where weaning was successful, values of P0.1 were less than or equal to 4.2 cm H2O, in chronic or non-chronic patients. Eighty-nine percent (89%) of the times when P0.1 values were higher than 4.2 cm H2O the same patients required ventilatory support, total (MV) or partial (IMV). These differences were statistically significant (p less than 0.01). We conclude that the P0.1 is an easily obtained non-invasive parameter, that can contribute along with other more conventional measurements to a superior indication for weaning.

Adult↗
PubMed1985

Flow-injection analysis of catecholamine secretion from bovine adrenal medulla cells on microbeads.

Bovine adrenal medullary cells have been cultured on microbeads which are placed in a low-volume flow system for measurements of stimulation-response parameters. Electronically controlled stream switching allows stimulation of cells with pulse lengths from 1 s to many minutes; pulses may be repeated indefinitely. Catecholamines secreted are detected by an electrochemical detector downstream from the cells. This flow-injection analysis technique provides a new level of sensitivity and precision for measurement of kinetic parameters of secretion. A manual injection valve allows stimulation by higher levels of stimulant in the presence of constant low levels of stimulant. Such experiments show interesting differences between the effects of K+ and acetylcholine on cells partially desensitized to acetylcholine.

Adrenal Medulla↗
PubMed1985

Observations on the axonal and neuronal typology in the commissure of the inferior colliculus of the rabbit.

Different types of neurons and fibres in the Commissura colliculi inferiores (CCI) of the rabbit are described using the Golgi rapid method. Neurons were classified according to soma shape, dendritic arborization and location within the commissure. Four main neuronal types were found i.e., (1) Vertical cells; (2) Multipolar cells; (3) Horizontal cells; (4) Small rounded cells. With exception of the latter, all neuron types could be divided into several cells varieties. Four different types of fibres were observed within the CCI: a) myelinated commissural fibres; b) fibres from the dorsal cortex of the colliculus; c) fibres from the dorsal PAG nucleus; d) intrinsic fibres from the neurons of the CCI. The results of this study demonstrate the non-homogeneous structure of the CCI, which was earlier shown in the cat and rat. Also, a division of some of the commissural neurons into local and projecting neurons, based on their axonal branching pattern is suggested.

Animals↗