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Biomedical subjects

J M Ferrer

Publications and source records attributed to J M Ferrer.

At least 73 records · Page 4Linked to original sources
PubMed1986

Increased acidophilia of eosinophil granules after EDTA treatment.

The acidophilic reaction of eosinophil leucocyte granules from human, pig and horse blood smears was investigated by using May-Grünwald-Giemsa staining after previous treatment with EDTA and sodium citrate solutions. The same peak at 530 nm, but absorption values considerably higher than those of controls, were found in eosinophil granules after application of chelating agents, indicating that removal of metal cations could unmask basic groups in these structures.

Animals↗
PubMed1986

Neurotransmitters, pathways and circuits as the neural substrates of self-stimulation of the prefrontal cortex: facts and speculations.

Through a multidisciplinary approach considerable progress has been made in understanding the neural substrates of self-stimulation (SS) of the medial prefrontal cortex (MPC). Thus, neuroanatomical studies have revealed that intrinsic neurones in the MPC seem to be the central elements responsible for initiating and maintaining this phenomenon in this area of the brain. Complementary to this central finding are the electrophysiological and neurohistological data reviewed here, showing that neurones in the MPC are directly activated and have monosynaptic feed-back connections with neurones located in areas which also support SS. These findings have given rise to the hypothesis that several single feed-back pathways or single circuits exist between points of SS in the MPC and points of SS in other areas of the brain. This hypothesis implies that SS in a particular area would depend not only on the intrinsic local activity induced by the electrical stimulation but on the functional and specific activity of other nuclei in the brain. The fact that lesions of single circuits, which are apparently involved in SS of the MPC such as the medial prefrontal cortex-ventrotegmental area-medial prefrontal cortex and medial prefrontal cortex-n. dorsomedialis of the thalamus-medial prefrontal cortex, do not produce a permanent decrease of SS, together with the finding that transynaptic connections seem to exist between MPC and other areas of the brain, suggests further that a complex rather than several single independent circuits could be at the neural basis of SS of the MPC. If that were the case, then SS of the MPC would not only depend upon local and single feed-back activity but upon specific functional feed-back activity among the nuclei, which in turn have single feed-back connections with the MPC (see the concept of 'complex circuit' outlined in the section of Behavioural studies). On the basis of this hypothesis no permanent changes should be expected after lesions of single pathways since physiological and even anatomical compensation could be reached through the rest of the undamaged circuit. That terminals containing specific neurotransmitters exist in layers of the PC where electrodes for SS are located has been reviewed in this paper. Some of these neurotransmitters have been suggested to be part of the local substrates activated by SS.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

CCK and other peptides modulate hypothalamic norepinephrine release in the rat: dependence on hunger or satiety.

The purpose of this investigation was to determine the functional relationship between putative satiety peptides and endogenous norepinephrine (NE) activity in the hypothalamus. Permanent guide cannulae for push-pull perfusion were implanted stereotaxically in Sprague-Dawley rats so as to rest above the medial or lateral hypothalamus (LH). Post-operatively, the animals were either satiated with food and water, both available ad lib, or fasted for 18-22 hr prior to an experiment. To perfuse a site in the LH, paraventricular (PVN) or ventromedial nucleus (VMN), a concentric 29-23 ga push-pull cannula system was lowered to a pre-determined site, in most cases after catecholamine stores had been pre-labeled with [3H]-NE. During control tests, an artificial CSF was perfused at a rate of 20-25 microliter/min for 5-8 min with a 5 min interval between each sample. The addition of cholecystokinin (CCK) in a concentration of 2.0-6.0 ng/microliter to the CSF perfused in PVN or VMN of the satiated rat enhanced the efflux of NE; however, in the fasted animal CCK often suppressed the catecholamine's release. Perfused in the LH, CCK exerted opposite effects, typically augmenting NE output when the rat was fasted but not affecting the amine's activity during the sated condition. Proglumide (1.2 micrograms/microliter) attenuated CCK's effect in releasing NE when the antagonist was perfused in the PVN of the satiated rat. Similar experiments in which neurotensin (NT) was perfused in the LH, PVN and VMN revealed virtually the same inverse effects on NE release in the fasted and satiated rat, which again were anatomically specific. Finally, insulin and 2-deoxy-D-glucose (2-DG) exerted similar state-dependent effects on the release of NE within LH and PVN. Overall, the results suggest that CCK or other neuroactive peptide could serve as a "neuromodulator" of the pre-synaptic release of NE within classical hypothalamic structures which are thought to underlie both hunger and satiety. The state-dependent nature of the peptides' activity on the noradrenergic feeding mechanism implies that these substances constitute a pivotal portion of the profile of factors which impinge functionally upon the hypothalamic neurons responsible for the feeding response and its cessation.

Animals↗
PubMed1986

Electronmicroscopical contrast by palladium chloride.

Thin sections of glutaraldehyde-fixed, epoxy resin-embedded bone marrow from rats were treated with 2% palladium chloride in 2% concentrated HCl. This procedure was found to induce high electron density in chromatin from all cell types and in cytoplasmic granules of neutrophils and eosinophils. In the latter, the crystalline body showed more contrast than the matrix.

Bone Marrow↗
PubMed1986

Oxidized p-phenylenediamine: observations on the staining reaction in epoxy embedded tissues.

p-Phenylenediamine (PPD) is easily oxidized to brown compounds which stain acidic substrates. On account of the spontaneous oxidation process, the colour of PPD increases and becomes ochre-brown in a few days, showing an absorption peak at lambda = 510 nm with shoulder at about 440 to 460 nm. Studies on the application of oxidized PPD as a stain for semi-thin sections revealed that some tissue components could be clearly visualized. After glutaraldehyde fixation, semi-thin and thin sections of animal tissues were treated with 0.5% aqueous PPD solutions which were aged for variable times at room temperature. Microvilli, goblet cell mucin, mast cell granules, cartilage matrix, collagen, elastin, keratohyalin granules, acrosomes, cytoplasmic granules of Drosophila hydei salivary glands and chromatin showed positive staining reactions after treatment of semi-thin sections with oxidized PPD (7-10 days aged) for 20-30 minutes. Microspectrophotometric studies revealed an absorption peak at lambda = 520-530 nm and a shoulder at lambda = 440-460 nm in goblet cell mucin stained by oxidized PPD. In the presence of anionic macromolecules, the main peak of oxidized PPD solutions showed a strong hyperchromism. Thin sections stained by oxidized PPD did not appear contrasted, but the treatment with 0.125% gold chloride (AuCl3) induced massive gold deposits in structures stained by oxidized PPD. Hyperchromic shifts were also produced in oxidized PPD solutions after the addition of small amounts of AuCl3. This procedure can be used as a simple and rapid staining method for epoxy sections, giving selective contrast for some tissue components.

Animals↗
PubMed1985

Suppression of self-stimulation of the medial prefrontal cortex after local micro-injection of kainic acid in the rat.

The question of whether neurons versus fibers of passage in the medial prefrontal cortex (MPC) are essential in maintaining self-stimulation of this same area of the brain was examined. Rats were prepared with electrode-guide cannulae implanted stereotaxically to rest within MPC. A micro-injection of (KA), 10 nmol/1.0 microliter, into the right MPC produced a clear degeneration of neuronal cell bodies characterized by picnocytosis and glial invasion of the tissue surrounding the tip of the electrode. These histopathological changes were correlated with a permanent abolition of self-stimulation of the right MPC. In contrast, self-stimulation of the contralateral side of the MPC, micro-injected with 0.9% NaCl vehicle as a control, was unaffected. These results suggest that neurons of the MPC are part of the neural substrate underlying self-stimulation behavior in this cortical area of the rat.

Animals↗
PubMed1984

Ruthenium red staining of polyanion containing structures in sections from epoxy-resin embedded tissues.

Staining by ruthenium red (0.5 mg/ml in borate buffer at pH = 9.2) has been used for light and electron microscopic visualization of polyanion containing structures in sections from glutaraldehyde-fixed, epoxy-embedded tissues. This staining technique can be applied in a simple and rapid way, showing the reactive cell components with suitable resolution and contrast. Preliminary spectrophotometric studies show the correspondence in absorption characteristics of the dye which is bound to polyanions in situ or in vitro.

Animals↗
PubMed1984

Blue molybdenum oxides: a stain for light and electron microscopy.

Blue molybdenum oxides (molybdenum blues) have been prepared from aqueous phosphomolybdic acid solutions and applied to thin and semi-thin sections of glutaraldehyde-fixed, epoxy-embedded tissues. A light blue colour and high electron opacity were found in mast cell granules, the secretion content of goblet cells, and cytoplasmic granules in Drosophila salivary glands. The possibility that binding of blue molybdenum oxides to polyhydroxylic components accounts for the staining and contrasting reactions in some cell structures is briefly discussed.

Animals↗
PubMed1983

Effects of agonists and antagonists of D1 and D2 dopamine receptors on self-stimulation of the medial prefrontal cortex in the rat.

The possible participation of D1 versus D2 dopamine receptors in mediating dopaminergic neurotransmission of self-stimulation (SS) in the medial prefrontal cortex (MPC) of the rat was studied neuropharmacologically. Intracerebral as well as intraperitoneal injections of agonists and antagonists of dopamine receptors were used in this study. In all experiments performed with systemic injections, spontaneous motor activity (SM) was measured parallel to self-stimulation behavior as control for non specific effects of the drugs. Intracranial injections were done unilaterally serving SS of the contralateral side (not injected or injected with 0.9% NaCl) as control in the same animals. Spiroperidol and pimozide were used as D1-D2 dopamine antagonists, while sulpiride was used as a specific D2 antagonist. Apomorphine was used as D1-D2 agonist, while bromocriptine and lergotrile were used at doses in which these ergot drugs are considered predominantly D2 agonists. Sulpiride, intraperitoneally or intracerebrally injected at the same locus at which the stimulating electrode was located produced no effect on SS. On the contrary, the D1-D2 antagonists, spiroperidol and pimozide intraperitoneally or intracerebrally injected produced a dose-dependent decrease on SS. On the basis of these data it is suggested, that the dopamine neurotransmission involved in SS of the MPC is mediated via D1 dopamine receptors. This suggestion is further emphasized by the results obtained with the agonists, apomorphine, bromocriptine and lergotrile. Apomorphine produced a dose-related decrease on SS and a decrease at lower doses and an increase at higher doses on SM. Bromocriptine and lergotrile had, on the contrary, no effect on SS and a dose-related decrease on SM.

Animals↗
PubMed1983

Mercurochrome: a fluorescent and electron opaque dye.

Mercurochrome was applied to tissues and tissue sections in an attempt to examine structural components either in visible light, fluorescence or electron microscopy. Samples of bone marrow from rats were fixed in glutaraldehyde alone, embedded in Durcupan, and studied by using semi-thin and thin sections. After treatment with mercurochrome in acetone before embedding, the eosinophilic granules from leucocytes and chromatin masses showed electron opacity as well as a yellowish green fluorescence under excitation with violet-blue or blue light. An additional treatment of sections with an alkaline hydroalcoholic solution of the dye allowed to visualize these structures under bright-field illumination and to improve the contrast in the electron microscope. This method offers the possibility to examine specific cell components by using a compound which simultaneously possesses staining, fluorescence, and electron microscopic contrasting properties.

Animals↗
PubMed1978

President's remarks.

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Academies and Institutes↗
PubMed1976

Immediate endoscopic diagnosis of upper gastrointestinal bleeding. Its accuracy and value in relation to associated pathology.

Two hundred sixty-two patients with active upper gastrointestinal (GI) bleeding underwent panendoscopy between July 1970 and March 1973. There was 100% accuracy of endoscopic diagnosis as to the anatomical site of bleeding; the etiopathologic definition was 94.7% accurate. The series was divided into two groups, 116 with "liver disease" and 146 with "no liver disease." There were 107 patients with varices: 21 fell into no liver disease (small varices) and 86 into liver disease (39 small and 47 large varices). All had associated gastritis. Three endoscopic bleeding patterns were identified in the liver disease group. Only 27% of the patients in the liver disease group with varices (cirrhotics) had frank variceal hemorrhage, whereas 57% bled from hemorrhagic gastritis. The diagnostic unit provided early diagnosis, meaningful therapy, organized data gathering, and rough estimates of ultimate prognosis.

Endoscopes↗
PubMed1975

What is clinical smoke poisoning?

In this 13-year study, 51 patients were admitted with the primary diagnosis of "smoke poisoning" "carbon monoxide (CO) poisoning" or "respiratory burns." Forty patients (78%) had diagnosis of smoke poisoning with minor or no skin burns. The study indicated that clinical diagnosis of CO poisoning cannot be made reliably without carboxyhemoglobin (COHg) determination and that smoke poisoning patients often had CO poisoning. Seventeen of 19 smoke poisoning patients (89%) had CO poisoning above COHb levels of 15% saturation. Carbon monoxide was successfully removed from the blood by improving alveolar ventilation and oxygen concentration. However, there were 2 smoke poisoning deaths as the result of gaseous chemical injury. There was a correlation coefficient of 0.87 between initial COHg levels and patients' hospital days primarily determined by patients' pulmonary complications. Since CO is non-irritating, COHb levels may be used as an additional indicator of suspected pulmonary injury by noxious combustion gases.

Animals↗