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Biomedical subjects

A Diaz

Publications and source records attributed to A Diaz.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Aneurysm of the postero-inferior cerebellar artery associated with arteriovenous malformation].

A saccular aneurysm of the posterior inferior cerebellar artery lying in the fourth ventricle and an arteriovenous malformation in the cerebellum fed by the same artery are reported. Clipping of the neck of the aneurysm and total removal of the arteriovenous malformation were performed successfully during one stage. Review of the pertinent literature indicates that the aneurysm of the posterior inferior cerebellar artery originates from the peripheral portion of the artery when associated with arteriovenous malformation. The treatment is often surgical with good results in more than 80% of cases. A one-stage operation is the method of choice. Embolization is not without risk and can be attempted when the PICA's course allows easy catheterization.

Aged↗
PubMed1999

Addressing health needs of female adolescents in modernizing countries.

Recent initiatives that focus on health care of female adolescents in the United States have not been adopted by most modernizing countries. Female adolescents, an age and gender group that suffers disproportionately from many behavioral health disorders, can benefit from regional and national health care policies that promote developmentally appropriate education and prevention. This commentary provides recommendations and concrete examples of approaches that improve health outcomes for female teens in modernizing nations. These include health information campaigns, empowerment education, the use of peer educators, and training of health care providers in adolescent-sensitive care.

Adolescent↗
PubMed1998

Differential regulation of cyclooxygenases 1 and 2 by interleukin-1 beta, tumor necrosis factor-alpha, and transforming growth factor-beta 1 in human lung fibroblasts.

In the present studies we found that incubation of human lung fibroblasts with transforming growth factor-beta 1 (TGF-beta 1) potentiated the interleukin-1 beta (IL-1 beta) and/or tumor necrosis factor-alpha (TNF-alpha)-stimulated production of prostaglandin E2 (PGE2). Analysis of fibroblast proteins showed the induction of cyclooxygenase-1 (Cox-1) by TGF-beta 1 and the induction of Cox-2 by IL-1 beta and TNF-alpha. The levels of transcripts for Cox-1 were minimally modified by IL-1 beta or TNF-alpha, however, they were increased by 12-fold by TGF-beta 1. Transcripts for Cox-2 were induced by IL-1 beta or TNF-alpha and their induction was potentiated by TGF-beta 1. TGF-beta 1 alone did not induce Cox-2 transcripts. In vitro transcription assays showed that IL-1 beta and TNF-alpha increased the transcription of the Cox-2 gene, whereas TGF-beta 1 had no effect. Addition of TGF-beta did not increase further the transcription of Cox-2 in IL-1 beta-treated cells, but increased the stability of the corresponding transcripts. The transcription rate of the Cox-1 gene was not increased by any of the cytokines studied. In summary, we demonstrate that the potentiation of PGE2 production by TGF-beta 1 in IL-1 beta and TNF-alpha-treated fibroblasts is the result of transcriptional stimulation of the Cox-2 gene by IL-1 beta and TNF-alpha and the stabilization of the resulting transcripts by TGF-beta 1.

Cells, Cultured↗
PubMed1998

Broad-spectrum, non-opioid analgesic activity by selective modulation of neuronal nicotinic acetylcholine receptors.

Development of analgesic agents for the treatment of severe pain requires the identification of compounds that are devoid of opioid receptor liabilities. A potent (inhibition constant = 37 picomolar) neuronal nicotinic acetylcholine receptor (nAChR) ligand called ABT-594 was developed that has antinociceptive properties equal in efficacy to those of morphine across a series of diverse animal models of acute thermal, persistent chemical, and neuropathic pain states. These effects were blocked by the nAChR antagonist mecamylamine. In contrast to morphine, repeated treatment with ABT-594 did not appear to elicit opioid-like withdrawal or physical dependence. Thus, ABT-594 may be an analgesic that lacks the problems associated with opioid analgesia.

Analgesics, Non-Narcotic↗
PubMed1998

Effects of interferon-gamma and tumor necrosis factor alpha on the expression of the genes encoding aggrecan, biglycan, and decorin core proteins in cultured human chondrocytes.

OBJECTIVE: To determine the effects of interferon-gamma (IFN gamma) and tumor necrosis factor alpha (TNF alpha), alone or in combination, on the expression of aggrecan, biglycan, and decorin core protein genes in human chondrocytes. METHODS: Isolated human chondrocytes were cultured on poly(2-hydroxyethyl methacrylate)-coated plastic dishes to prevent the loss of cartilage-specific phenotype, and the effects of IFN gamma and TNF alpha, alone or in combination, on aggrecan, biglycan, and decorin core protein gene transcription and steady-state messenger RNA (mRNA) levels were examined. RESULTS: The addition of IFN gamma (1.5 pM) or TNF alpha (0.3 pM) caused a decrease in the steady-state level of aggrecan mRNA (-25% and -15%, respectively), and the combination of these low-concentration cytokines caused a potent inhibition (-66%). These effects were the result of a decrease (-50%) in the transcription rate of the corresponding gene. At the concentrations used, IFN gamma did not alter the levels of biglycan mRNA or the transcription rates of the biglycan core protein gene. In contrast, TNF alpha decreased biglycan steady-state mRNA levels (-62%) and the biglycan core protein gene transcription rate (-18%). The combination of IFN gamma and TNF alpha resulted in a potentiation of the inhibitory effects of TNF alpha on biglycan mRNA levels (-79%) and transcription rate of the biglycan core protein gene (-46%). IFN gamma produced a modest decrease in decorin mRNA levels (-23%) and decorin core protein gene transcription rate (-17%). In contrast, TNF alpha resulted in a marked increase in decorin mRNA levels (+260%) that was not the result of transcriptional regulation. Notably, the combination of IFN gamma and TNF alpha potentiated the inhibitory effects of IFN gamma on decorin mRNA (-80%) and on the transcription of the corresponding gene (-43%). Similar results were obtained in fetal and adult articular chondrocytes. CONCLUSION: These data demonstrate that 1) the expression of the core protein genes encoding the cartilage proteoglycans aggrecan, biglycan, and decorin is differentially regulated by IFN gamma and TNF alpha; 2) these effects are mediated by transcriptional and posttranscriptional mechanisms; and 3) the combination of the 2 cytokines causes a potent inhibitory effect on the expression of the genes for the core proteins of these 3 proteoglycans, which occurs largely at the transcriptional level. The inhibition of aggrecan, decorin, and biglycan core protein gene expression by the combination of IFN gamma and TNF alpha may contribute to the cartilage destruction that is characteristic of inflammatory joint diseases.

Adult↗
PubMed1998

A randomized, blinded, comparative trial of one pepsin-digested and two whole IgG antivenoms for Bothrops snake bites in Uraba, Colombia. The Regional Group on Antivenom Therapy Research (REGATHER).

The therapeutic efficacy and the incidence of early antivenom reactions (EARs) were compared in a clinical trial performed in 79 patients bitten by Bothrops sp. in Urabá, Colombia. Patients were randomized into three groups according to the antivenom administered: A (n = 30, Butantan polyspecific, pepsin-digested Bothrops antivenom); B (n = 27, Butantan polyspecific, whole IgG Bothrops antivenom); and C (n = 22, Colombian commercial, monovalent, whole IgG Bothrops antivenom). The groups were comparable in all clinical and epidemiologic aspects; 33 patients had mild, 22 moderate, and 24 severe envenoming. At the doses used (two, four, and six vials [10 ml/vial] for mild, moderate, and severe envenomings, respectively) there were no differences between the antivenoms in restoring normal hemostatic parameters within 24 hr. The evolution of local envenoming was comparable in the three groups. Serum venom/antivenom kinetics determined by ELISA showed a complete clearance of venom levels 1 hr after treatment in mild/moderate envenomings. In severe cases, venom levels remained detectable up to 24 hr and recurrence of antigenemia was observed in some cases. Antivenom concentrations remained at high levels up to 24 hr of treatment. The incidence of EARs was significantly different in the groups: A (36.7%), B (11.1.%), and C (81.8%). There were no life-threatening anaphylactic reactions. We conclude that the efficacy of the three antivenoms was similar in neutralizing human Bothrops envenomings and that the production of whole IgG antivenoms by caprylic acid fractionation is a good alternative for reducing the incidence of EARs.

Adolescent↗
PubMed1998

Cultural and medical issues of Latino adolescents.

While the cultural and medical issues of providing care to immigrants have been primarily addressed in the adult literature, this article discusses how these issues concern Latino adolescents. Recognizing the multitude and complexity of immigrant experiences and responses to the acculturation process, the authors address myths and stereotypes associated with Latino culture that interfere with health care delivery.

Adolescent↗
PubMed1998

[Trauma-induced arterial aneurysm in childhood. Report of a case and review of the literature].

We report a case of calloso-marginal artery aneurysm in a 3 year old child, revealed 3 weeks after a craniocerebral trauma with frontal embarrure, by a sudden subarachnoidal hemorrhage syndrome with loss of consciousness and coma. The CT scan confirmed the subarachnoid hemorrhage in all the basal cisterns, with an interhemispheric subdural hematoma. The carotid angiography showed a right calloso-marginal aneurysm. The child has been operated (coagulation of the artery and excision of the false aneurysm. We studied the mechanism of pediatric post-traumatic aneurysm, the histological and clinical presentation emphasizing the necessity of a complete neuroradiological exploration when new neurological symptoms develop after head trauma. Neurosurgical and/or endovascular neuroradiological treatment is mandatory.

Accidents, Traffic↗
PubMed1998

[Chronic subdural hematoma in utero. Case report with literature review].

We present a case of chronic subdural hematoma diagnosed in utero by ultrasonography, and MRI at 31 weeks gestation. No cause of usual intracranial hemorrhage was found. There was no trauma. The child was operated after induced vaginal delivery at 37 weeks gestation, with good results and normal neuropsychological development after one year. We discuss the symptomatology and the therapeutic attitude in such cases.

Adult↗
PubMed1998

[Intra-orbital dacryops. Report of a case].

We report a case of intra-orbital Dacryops in a 7-year-old child. The presenting sign was progressive exophtalmus. The patient was operated via a lateral approach allowing total removal of the cyst without recurrence after one year. The clinical, radiological (CT Scan and MRI) and therapeutical aspects are discussed.

Child↗
PubMed1997

BU-224 produces spinal antinociception as an agonist at imidazoline I2 receptors.

In this electrophysiological study, the effect of BU-224 (2-(4,5-dihydroimidazol-2yl)-quinoline hydrochloride)), a novel high affinity imidazoline I2 receptor ligand, was tested on the responses of nociceptive neurones in the spinal dorsal horn. When applied spinally, akin to an intrathecal application (i.t.), BU-224 (5-250 microg) reduced the nociceptive responses of dorsal horn neurones, producing a dose-dependent inhibition of C-fibre evoked responses, postdischarge and wind-up of the cells. A complete block of the antinociceptive effects was produced when idazoxan (100 microg), with both alpha2-adrenoceptor and imidazoline I2 receptor antagonist actions, was administered i.t. 10 min prior to the maximal dose of BU-224 tested. The nonselective alpha2-adrenoceptor antagonist, yohimbine (150 microg) only partially attenuated the inhibitory effects of BU-224 when administered i.t. 10 min prior. The highly selective alpha2-adrenoceptor antagonist, atipamezole (100 microg) produced no greater reversal than yohimbine under the same conditions. Although BU-224 has been reported to possess high affinity for imidazoline I2 receptors, a minor action at spinal alpha2-adrenoceptor receptors cannot be discounted. These results demonstrate that BU-224 is an agonist and that imidazoline I2 receptors, present in the dorsal horn, might play a role in spinal nociception, although further studies are needed to fully elucidate their functional roles.

Adrenergic alpha-Antagonists↗
PubMed1997

On stage single cell identification of rat spermatogenic cells.

The study of spermatogenic cell physiology has been hindered by the absence of unbiased methods of identification of cells upon which single cell techniques are being applied. In this work, we have used histochemical techniques, digital videoimaging, quantification of chromatin-bound DNA probes, and measurements of cell diameter to identify single spermatogenic cells at different periods of development. Our criteria of identification permit the definition of four developmental stages of spermatogenesis on which to perform single cell analyses: spermatogonia B/preleptotene spermatocytes, leptotene/zygotene spermatocytes, pachytene spermatocytes, and round spermatids. The use of voltage-sensitive dyes and Ca(2+)-sensitive dyes does not interfere with the estimations of DNA content. The estimations of DNA content of spermatogenic cells can be performed both with near-UV excited dyes (H33342) and long wavelength-excited dyes (ethidium bromide), allowing the use of a wide range of physiological and immunocytochemical fluorescent probes to study the spermatogenic process.

Age Factors↗
PubMed1997

Blockade of spinal N- and P-type, but not L-type, calcium channels inhibits the excitability of rat dorsal horn neurones produced by subcutaneous formalin inflammation.

The effects of the intrathecal (i.t.) administration of different voltage-sensitive calcium channel (VSCC) blockers were studied in the formalin model of inflammation. The responses of convergent dorsal horn neurones after the subcutaneous injection of formalin (5% formaldehyde, 50 microliters volume) were recorded extracellularly in rats under halothane anaesthesia. Administration of the L-type calcium channel blocker verapamil, 5 and 50 micrograms, before formalin injection had no effect on either the first or second phase of the formalin response. Pre-treatment with the N-type calcium channel blocker omega-Conotoxin-GVIA, 0.1 and 0.4 microgram, reduced both phases of the formalin response. The low dose of omega-Conotoxin-GVIA significantly inhibited the first phase response whereas the high dose significantly reduced the second phase. Pre-treatment with the P-type calcium channel blocker omega-Agatoxin-IVA, 0.125 and 0.5 microgram, did not cause a significant inhibition of the first phase whereas a marked dose-related reduction in the second phase of formalin response was found with the high dose producing 95% inhibition. These results demonstrate that spinal N- and P-type, but not L-type, VSCCs are involved in the inflammation-evoked hyperexcitability of dorsal horn neurones after peripheral formalin injection. Since selective antagonists for each type of VSCC had differential effects on the formalin response, it is suggested that each type of VSCC could be preferentially regulating or coupled to the release of certain neurotransmitters in the enhanced nociceptive transmission at the spinal level following formalin inflammation.

Animals↗