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A Parent

Publications and source records attributed to A Parent.

At least 181 records · Page 10Linked to original sources
PubMed1987

Pre-mRNA splicing and the nuclear matrix.

We examined the relationship between pre-mRNA splicing and the nuclear matrix by using an in vivo system that we have developed. Plasmids containing the inducible herpesvirus tk gene promoter linked to an intron-containing segment of the rabbit beta-globin gene were transfected into HeLa cells, and then the promoter was transactivated by infection with a TK- virus. Northern analysis revealed that the globin pre-mRNA and all its splicing intermediates and products are associated with the nuclear matrix prepared from such transfected cells. When the nuclear matrix was incubated with a HeLa cell in vitro splicing extract in the presence of ATP, the amount of matrix-associated precursor progressively decreased without a temporal lag in the reaction, with a corresponding increase in free intron lariat. Thus, most of the events of the splicing process (endonucleolytic cuts and branching) occur in this in vitro complementation reaction. However, ligation of exons cannot be monitored in this system because of the abundance of preexisting mature mRNA. Since the matrix is not a self-splicing entity, whereas the in vitro splicing system cannot process efficiently deproteinized matrix RNA, we conclude from our in vitro complementation results (which can be reproduced by using micrococcal nuclease-treated splicing extract) that the nuclear matrix preparation retains parts of preassembled ribonucleoprotein complexes that have the potential to function when supplemented with soluble factors (presumably other than most of the small nuclear ribonucleoproteins known to participate in splicing) present in the HeLa cell extract.

Animals↗
PubMed1987

Decreased in vitro responses to vasoconstrictors during gestation in normotensive and spontaneously hypertensive rats.

We have investigated the in vitro vascular responses to vasoconstrictor agents in pregnant normotensive (Sprague-Dawley (SDR) and Wistar-Kyoto (WKR] and spontaneously hypertensive rats (SHR) to measure the sensitivity and contractility of blood vessels of pregnant rats. In the perfused mesenteric vascular bed from rats on the 21st day of gestation, the concentration-response curves for the increase in perfusion pressure by arginine8-vasopressin and norepinephrine were displaced to the right by comparison to nonpregnant female rats when all strains of rats were considered together. The increase in EC50 to both agents in pregnant rats was from 1.3- to 2.7-fold in the mesenteric bed; SDR showed the highest increase in EC50, followed by SHR and WKR. No consistent effect was observed on the maximum response. Similar results were obtained in isolated portal veins for angiotensin II and norepinephrine, except that the increase in EC50 in pregnant rats was smaller in magnitude (from 1.0 to 1.7) and followed the same interstrain pattern. These data show that the decreased responsiveness to vasoconstrictor agents in pregnant rats observed in vitro is similar in normotensive and hypertensive rats and suggest that the factor(s) responsible for this effect is a phenomenon affecting vascular smooth muscle in both arteries and veins.

Angiotensin II↗
PubMed1986

Neuropeptide Y-immunoreactive neurons in the striatum of cat and monkey: morphological characteristics, intrinsic organization and co-localization with somatostatin.

A detailed study of the distribution of neuropeptide Y (NPY) in the striatum of squirrel monkey (Saimiri sciureus) and cat was undertaken by means of indirect immunofluorescence and peroxidase-antiperoxidase (PAP) methods. In monkey, the NPY-immunoreactivity is homogeneously distributed along the entire extent of the caudate nucleus (CD) and putamen (PUT), while in cat marked heterogeneities are noted. In the CD of cat, the NPY-immunoreactive fibers and cell bodies are concentrated in numerous patches of various sizes, which can be readily distinguished from zones of poor NPY-immunostaining. In the CD and PUT of squirrel monkey the NPY-positive neurons are either triangular, fusiform or globular, with long and smooth dendrites branching infrequently. The numerical density of NPY-immunoreactive cell bodies is greater in the CD than in the PUT, and it increases markedly along the rostrocaudal extent of the striatum. In the rostral CD and PUT the densities are 23 cells/mm2 and 14 cells/mm2, respectively, whereas the values for caudal CD and PUT are 35 cells/mm2 and 20 cells/mm2, respectively. Quantitative measurements reveal that these NPY-immunoreactive cells belong to a single subset of striatal neurons having a maximum diameter of 19.2 +/- 0.1 micron and a cross-sectional area of 145.5 +/- 0.6 micron2 (mean +/- S.E.M.; n = 1238 CD cells and 1169 PUT cells). Furthermore, experiments combining the use of lectin-conjugated HRP as retrograde tracer with PAP immunohistochemical method demonstrate that striatal NPY-immunoreactive neurons in squirrel monkey and cat do not project outside the striatum. Finally, co-localization studies in monkey reveal that the vast majority of striatal NPY-positive neurons also contains somatostatin. These results show that the NPY-immunoreactive neurons in mammalian striatum form a subpopulation of medium-sized interneurons containing somatostatin.

Animals↗
PubMed1986

Frequency of infections in cirrhotic patients presenting with acute gastrointestinal haemorrhage.

The frequency of infection at the time of admission with upper gastrointestinal haemorrhage has been determined in 149 successive cirrhotic patients admitted to an intensive care unit. Infection status was investigated by clinical examination, chest X-ray, and blood, urine and ascitic fluid culture. At initial examination infection was present in 32 patients (22 per cent) and was often in the form of septicaemia or spontaneous peritonitis; the bacteria responsible were frequently digestive in origin. At endoscopy, acute lesions of gastroduodenal mucosa were more frequent among infected patients, whereas gastro-oesophageal varices and chronic gastroduodenal ulcers were more frequent among the non-infected patients. Acute mucosal lesions were observed in 70 per cent of infected patients and in 19 per cent of non-infected patients. The mortality rate was higher in infected patients. Infection and the frequency of acute mucosal lesions were related to the severity of the cirrhosis. It is suggested that these lesions could be due to stress secondary to infection.

Acute Disease↗
PubMed1986

Differential connections of caudate nucleus and putamen in the squirrel monkey (Saimiri sciureus).

The organization of the subcortical connections of caudate nucleus and putamen in the squirrel monkey was studied using horseradish peroxidase conjugated to wheat germ agglutinin as anterograde and retrograde neuronal tracer. The tracer was injected in similar quantities in the putamen on the left side and in the caudate nucleus on the right side in 10 monkeys, and its presence was revealed by means of the tetramethylbenzidine method. The study of anterogradely labeled fibers visualized after such injections shows that putaminofugal fibers terminate massively in the ventral two-thirds of the globus pallidus, where they display a band-like arrangement, and much less abundantly in the caudal third of the substantia nigra. In contrast, caudatofugal fibers occupy only the dorsal third of globus pallidus but arborize profusely in the rostral two-thirds of substantia nigra. In the pars reticulata of the substantia nigra the caudatonigral fibers form a highly complex network composed of fiber trabeculae while the putaminonigral fibers occur as more discrete fascicles confined to the dorsolateral region of the structure. In the pars compacta of the substantia nigra the retrogradely labeled cells occur in the form of clusters that are closely intermingled with clusters of unlabeled neurons. The labeled-cell clusters are particularly dense on the putamen-injected side and more loosely organized on the caudate-injected side. On both sides, however, the striatonigral fibers that reach the substantia nigra pars compacta can be seen to terminate almost exclusively upon clusters composed of retrogradely labeled cells, suggesting the existence of a precise reciprocal link between nigral and striatal neuronal aggregates. At thalamic levels the retrogradely labeled cells are distributed according to a strikingly asymmetric pattern. For instance, a prominent labeling of neurons in the central superior lateral nucleus is seen only on the caudate-injected side. Furthermore, in the centromedian/parafascicular complex retrograde cell labeling is seen exclusively in parafascicular nucleus on the caudate-injected side and only in the centromedian nucleus, except its lateralmost portion, on the putamen-injected side. Control experiments involving injection of the tracer in cerebral cortex overlying the striatum reveal that the neurons in the lateral segment of the centromedian, which do not project to striatum, are in fact reciprocally connected with the cerebral cortex. In addition, our data show that some of the so-called "specific" thalamic nuclei contribute significantly to the thalamostriatal projection in monkey.(ABSTRACT TRUNCATED AT 400 WORDS)

Amygdala↗
PubMed1986

Vasopressin responses and receptors in the mesenteric vasculature of estrogen-treated rats.

The effect of treatment with estrogens on the biological activity of arginine8 vasopressin (AVP) in the in vitro perfused mesenteric vascular bed and on the binding characteristics of [3H]AVP on membranes prepared from the same vascular bed was studied. Female rats treated with estradiol (400 micrograms/24 h sc), compared with ovariectomized rats, had an increase in the maximum response to AVP (from 128 +/- 3 to 153 +/- 3 mmHg) in the perfused preparation and an increase in the density of AVP binding sites (from 402 to 732 fmol/mg protein) in the membrane preparation. In male rats, the injection of estradiol increased the maximum response to AVP (from 109 +/- 4 to 137 +/- 3 mmHg) and the density of AVP binding sites (from 289 to 519 fmol/mg protein). The effective concentration producing 50% of maximum response of AVP in the perfused preparation was higher in male than in female rats, while the Kd in the binding experiments was similar in the four experimental groups. Our results show that estrogens upregulate the number of AVP binding sites, leading to an increase in the pressor response to AVP in the rat mesenteric vascular bed.

Animals↗
PubMed1985

Distribution of enkephalin-immunoreactive neurons in the forebrain and upper brainstem of the squirrel monkey.

The distribution of enkephalin-immunoreactive neuronal profiles in the forebrain and upper brainstem of the squirrel monkey (Saimiri sciureus) was studied by means of the indirect immunofluorescence method. Numerous enkephalin-immunoreactive cell bodies and fibers were disclosed in various regions including cerebral cortex, hippocampus, caudate nucleus, putamen, nucleus accumbens, septal area, olfactory tubercle, substantia innominata, amygdala, various hypothalamic and thalamic nuclei, periaqueductal gray, midbrain reticular formation and interpeduncular nucleus. Some of the highest concentrations of enkephalin-positive fibers in the squirrel monkey brain were found in the external segment of the globus pallidus, the outer layer of the median eminence, and in the pars reticulata of the substantia nigra. Overall, the pattern of distribution of the enkephalin-immunoreactive cell bodies and fibers in the forebrain and upper brainstem of the squirrel monkey is similar to that found in the rat, except that the density of positive neuronal profiles in the entire forebrain appears much higher in monkey than in rat. Furthermore, the very dense network of enkephalin-immunoreactive fibers disclosed in the substantia nigra pars reticulata of monkey appears to be lacking in rat.

Amygdala↗
PubMed1985

Distribution of neuropeptide Y immunoreactivity in the basal forebrain and upper brainstem of the squirrel monkey (Saimiri sciureus).

The distribution of neuropeptide Y (NPY) immunoreactivity in the brain of the squirrel monkey (Saimiri sciureus) was studied by means of the indirect immunofluorescence, peroxidase-antiperoxidase, and avidin-biotin-complex methods. The antiserum used was raised in rabbits and did not show any significant crossreactivity with related peptides including peptide YY and avian pancreatic polypeptide. In the upper brainstem of the squirrel monkey a dense NPY-immunoreactive terminal field is seen in lateral parabrachial area, locus coeruleus, and interpeduncular nucleus. A small group of NPY-immunoreactive cell bodies is present in the lateral habenula and a moderate number of NPY-immunoreactive fibers occurs in periaqueductal gray and nucleus raphe pallidus. The substantia nigra (SN) appears mostly devoid of NPY immunoreactivity whereas the ventral tegmental area contains a few reactive fibers. In the hypothalamus the medial preoptic area as well as the arcuate and paraventricular nuclei receive a strikingly dense NPY innervation. In addition, numerous NPY-positive cell bodies are found within the dorsomedial half of the supraoptic nucleus but very few are seen in paraventricular nucleus. A large number of NPY-immunoreactive cell bodies is also present in arcuate nucleus. In the basal telencephalon NPY-immunoreactive cells abound mostly in striatum, but some are also found in the amygdala (particularly basal, central, and lateral amygdaloid nuclei), the claustrum, and in the bed nucleus of the stria terminalis. Intensely reactive network of NPY-immunoreactive fibers is also present in all of these structures. In striatum, the numerous, fine and non-varicose NPY-immunoreactive fibers, as well as the NPY-positive cell bodies, are slightly more abundant in caudate nucleus than in putamen. The globus pallidus (GP) is mostly devoid of NPY-immunoreactive fibers and terminals. The fact that the two major recipient structures of striatal outflow (SN and GP) do not receive significant NPY input suggests that the striatal NPY-containing neurons are intrinsically organized.

Animals↗
PubMed1985

[Hypophosphoremia during mechanical ventilation for chronic obstructive bronchopathies].

Hypophosphoremia may interfere with respiratory function in chronic obstructive pulmonary diseases (COPD) through different mechanisms: muscular exhaustion and weakness. Accordingly, the frequency and magnitude of hypophosphoremia was studied in 36 consecutive patients with acute respiratory failure and mechanical ventilation. Initial phosphoremia was normal (1,32 +/- 0,12 mmol/l) but often and rapidly decreased in all patients after mechanical ventilation had been started (0,54 +/- 0,14 mmol/l after 24 h). After this, phosphoremia remained low, slowly increasing with continued enteral nutrition (2000 Kcal, 276 g of glucides, 33 mmol/l of phosphorus). Four patients had severe hypophosphoremia after 24 h of mechanical ventilation (less than 0,30 mmol/l). Phosphoremia returned to a normal level 36 h after extubation. Hypophosphoremia was closely linked to pH improvement (r = + 0,67, P less than 0,001) and was paralleled by a drop in phosphaturia, suggesting intra-cellular penetration of phosphorus.

Acidosis↗
PubMed1984

Thalamic projections of nucleus reticularis thalami of cat: a study using retrograde transport of horseradish peroxidase and fluorescent tracers.

The retrograde transport of horseradish peroxidase (HRP) and fluorescent tracers after injections in various thalamic nuclei was used to investigate the relative density of retrogradely labeled cells in different districts of reticularis thalami (RE) nuclear complex of cat. The RE nucleus was left virtually free of labeling only after injections localized into the anterior nuclear group; in those experiments, heavy retrograde labeling was obtained in mammillary nuclei. The major targets of RE cells proved to be centralis lateralis-paracentralis (CL-PC) and centrum medianum-parafascicularis (CM-PF) intralaminar nuclei. The projections to various intralaminar nuclei mainly arise in the rostral pole and rostrolateral part of RE nucleus and are reciprocal to intralaminar-RE pathways disclosed by Jones ('75). The RE territories labeled following injections in relay and associational nuclei are more restricted and are located contiguously and slightly anteriorly to a given nucleus. There was a very small proportion of doubly labeled RE cells after injections with fluorescent tracers in different nuclei. This was not due to a technical failure since many double-labeled neurons were found in the same material in medial globus pallidum after thalamic and midbrain injections (see companion paper by Parent and Steriade, '84). We conclude that most individual RE axons arborize in only one thalamic nucleus or nuclear group. An additional finding was the existence of intralaminar-to-relay (CL-PC to VA-VL) projections.

Animals↗
PubMed1984

Midbrain tegmental projections of nucleus reticularis thalami of cat and monkey: a retrograde transport and antidromic invasion study.

The projections of reticularis thalami (RE) neurons to midbrain reticular formation (MRF) and superior colliculus (SC) were studied in cat and monkey by using retrograde transport techniques and antidromic identification. The projections to MRF arise in rostral parts and lateral extent of RE nuclear complex whereas RE fibers to SC predominantly originate in the RE posteroventral district. Following injections of horseradish peroxidase (HRP) or fluorescent tracers into the MRF territory, retrogradely labeled neurons were always more numerous in the lateral hypothalamus and zona incerta than in the continuing RE wing. There were only very few doubly labeled RE cells following injections of fluorescent tracers into the midbrain tegmentum and thalamic nuclei, despite the fact that numerous doubly labeled cells occurred in the internal part of globus pallidum and pars reticulata of substantia nigra in the same animals. Control injections in the pons showed that RE labeling after midbrain injections was not due to uptake by fibers coursing more caudally. Antidromic identification experiments in cat confirmed the existence of a descending RE input to midbrain and further indicated that RE-midbrain projections consist of slow-conducting (congruent to 1 m/second) axons.

Afferent Pathways↗
PubMed1984

The striatopallidal and striatonigral projections: two distinct fiber systems in primate.

The use of the fluorescence retrograde double-labeling method has revealed that striatal neurons projecting to the globus pallidus in the squirrel monkey are mainly confined to the putamen whereas those projecting to the substantia nigra occur mostly in the caudate nucleus. Only about 10% of the striatal neurons were found to be double-labeled after injections into the globus pallidus and substantia nigra. The segregation of the putaminofugal and caudatofugal projections was further confirmed by the anterograde tracing of WGA-HRP. These findings do not fit in the current unitary concept of the striatofugal fiber system. Instead, they suggest that the striatopallidal and striatonigral projections exist largely as two distinct subsystems in the primate.

Animals↗
PubMed1984

The occurrence of large acetylcholinesterase-containing neurons in human neostriatum as disclosed in normal and Alzheimer-diseased brains.

The human neostriatum was found to contain large neurons (maximum diameter: 30-40 microns) that stain intensely for acetylcholinesterase (AChE). These neurons are few in number, representing less than 5% of the total striatal neuronal population, and appear uniformly scattered throughout the caudate nucleus and putamen. They are morphologically similar to the AChE-containing neurons disclosed in the striatum of rat, cat and monkey after AChE inhibitor (DFP) pretreatment. In Alzheimer-diseased brains the number, morphological characteristics, and staining intensity of the striatal AChE neurons were found to be unaltered despite a marked loss of AChE cells in the adjoining nucleus basalis. These findings suggest that large intrinsic cholinergic neurons exist in human neostriatum and that these elements, in contrast to those of nucleus basalis, are not affected in Alzheimer's disease.

Acetylcholinesterase↗
PubMed1984

Distribution of substance P and enkephalin-like immunoreactivity in the substantia nigra of rat, cat and monkey.

A comparative study of the distribution of substance P (SP) and enkephalin (ENK) immunoreactivity in the substantia nigra (SN) of the rat, cat and squirrel monkey (Saimiri sciureus) was undertaken by means of the indirect immunofluorescence technique. In the rat a dense neuronal network composed of fine fibers displaying SP immunoreactivity is uniformely distributed throughout the rostrocaudal extent of the substantia nigra pars reticulata (SNr) and in the ventral part of substantia nigra pars compacta (SNc). Some coarse SP-positive fibers also occur in SNc. In addition, ENK-immunoreactive fibers are scattered amongst SNc neurons but abound particularly in the caudolateral part of SNr. In cat innumerable fine SP-positive fibers are distributed in SNr according to a pattern similar to that found in rat. ENK-immunoreactive fine fibers are densely packed in the ventromedial part of SNr whereas coarse ENK fibers are scattered in both SNc and SNr but abound particularly in the caudolateral portion of SNr. In monkey fine SP and ENK-immunoreactive fibers occur in very large number in SNr. These two types of fibers are distributed according to a similar but strikingly complex and heterogeneous pattern. In addition, coarse fibers displaying either SP or ENK immunoreactivity are scattered amongst the SNc neurons in monkey. These findings reveal that SP immunoreactive fibers are present in large number and are distributed according to a somewhat similar pattern in rat, cat and monkey. In contrast, the number of ENK-positive fibers and the complexity of their organizational feature in SN increase strikingly from rodent to primate.

Animals↗
PubMed1984

Distribution of acetylcholinesterase-containing neurons in the basal forebrain and upper brainstem of the squirrel monkey (Saimiri sciureus).

The topographical distribution of neurons containing acetylcholinesterase (AChE, EC 3.1.1.7) in the basal forebrain and upper brainstem of the squirrel monkey (Saimiri sciureus) was studied by means of Butcher's pharmacohistochemical technique which involves staining for AChE at various times after the systemic administration of the AChE inhibitor di-isopropylphosphorofluoridate (DFP). Only those neurons whose AChE staining was as intense as that of known cholinergic neurons present in the same material (e.g., neurons of cranial nerve nuclei) were examined and mapped. Three major collections of such strongly-stained AChE neurons were disclosed in squirrel monkey brain: one located in the striatum, the other lying along the ventralmost aspects of the basal forebrain, and a third one present within the midbrain-pontine tegmentum. The striatal AChE neurons vary in shape from fusiform with 2 thick processes to polygonal with 4-5 thinner processes. They are uniformly scattered throughout the caudate nucleus and putamen and represent only a small proportion of the total striatal cell population (4-6 cells/mm2). They most likely correspond to the aspiny type II cells described in Golgi material of monkey striatum. Similar neurons occur also in ventral striatal areas comprising nucleus accumbens septi and the deep polymorph layer of the olfactory tubercle. The second major AChE neuronal population is composed of the magnocellular neurons that form a somewhat continuous chain of neuronal aggregates extending rostrocaudally from the septal region to the caudal pole of the lentiform nucleus. It includes the neurons of the medial septal nucleus, the nucleus of the diagonal band of Broca and the nucleus basalis of Meynert, all displaying strikingly similar morphological and histochemical characteristics. The AChE neuronal population of nucleus basalis encroaches markedly upon the lateral hypothalamus laterally and the globus pallidus dorsally. The third important AChE cell collection occurs within the pedunculopontine nucleus area in upper brainstem. In that constellation, the AChE neurons are clustered in 2 continuous cell groups: one located dorsolaterally, the other lying ventromedially to the brachium conjunctivum. The thick processes of these neurons form impressive AChE neuronal networks that surround and pervade the brachium conjunctivum over long distances. This cell group, which is one of the most highly AChE reactive structures of the entire brain in the squirrel monkey, may provide a major cholinergic input to various basal ganglia structures, particularly the substantia nigra.

Acetylcholinesterase↗
PubMed1984

[Keratomycosis and keratoplasty].

Three cases of corneal perforation in keratomycosis are reported. In the first two cases the etiological diagnosis had been made from the anatomo-pathological examination of the excised corneal buttons. The mycotic origin in the third case was known before perforation from corneal cultures. Although the prognosis of this condition is usually poor, the post-keratoplasty evolution in the three cases was uncomplicated. The authors analyse the peculiarities of corneal mycotic abscess and discuss the appropriate diagnostic approach and management. Treatment must be performed before intraocular mycotic invasion occurs, because of the poor intraocular diffusion of antifungal agents. In this case, penetrating keratoplasty is not as dangerous as previously reported; and moreover, allows simultaneous treatment of the mycosis and the anatomical and functional repair of the cornea.

Abscess↗