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Biomedical subjects

A Gonzalez

Publications and source records attributed to A Gonzalez.

At least 55 records · Page 3Linked to original sources

A phase II study of gemcitabine and cisplatin combination as induction chemotherapy for untreated locally advanced cervical carcinoma.

BACKGROUND: Cisplatin-based chemoradiation for locally advanced cervical carcinoma is now the standard of care for most patients with cervical carcinoma. However, induction chemotherapy followed by surgery, particularly with newer agents or combinations remains to be explored. This study was undertaken to evaluate the antitumor activity and toxicity of gemcitabine in combination with cisplatin for untreated locally advanced cervical carcinoma. PATIENTS AND METHODS: Open-label, single center, phase II, non-randomized study of neoadjuvant gemcitabine plus cisplatin. Forty-one patients with histologic diagnosis of cervical carcinoma, with no previous treatment and staged as IB2 to IIIB, were treated with three 21-day courses of cisplatin 100 mg/m2 day I and gemcitabine 1000 mg/m2 days 1 and 8, followed by locoregional treatment with either surgery or concomitant chemoradiation. Response and toxicity were evaluated before each course and at the end of chemotherapy. RESULTS: All patients were evaluated for toxicity and 40 for response. The overall objective response rate was 95% (95% confidence interval (CI): 88%-100%) being complete in 3 patients (7.5%) and partial in 35 (87.5%). A complete pathological response was found in 6 (26%) of the 23 patients that underwent surgery. Granulocytopenia grades 3-4 occurred in 13.8% and 3.4% of the courses, respectively, whereas non-hematological toxicity was mild. CONCLUSIONS: Induction chemotherapy with the combination of gemcitabine and cisplatin is highly active for untreated cervical cancer patients and has an acceptable toxicity profile.

Adenocarcinoma↗

Damage control, rather than unresponsiveness, effected by protective DX5+ T cells in autoimmune diabetes.

The progression of autoimmune diabetes is regulated. We examined here the cellular controls exerted on disease that developed in the BDC2.5 T cell receptor-transgenic model. We found that all BDC2.5 mice with a monoclonal, beta cell-reactive, T cell repertoire developed diabetes before 4 weeks of age; transfer of splenocytes from young standard NOD (nonobese diabetic) mice into perinatal monoclonal BDC2.5 animals protected them from diabetes. The protective activity was generated by CD4+ alphabeta T cells, which operated for a short time at disease initiation, could be partitioned according to DX5 cell surface marker expression and split into two components. Protection did not involve clonal deletion or anergy of the autoreactive BDC2.5 cells, permitting their full activation and attack of pancreatic islets; rather, it tempered the aggressiveness of the insulitic lesion and the extent of beta cell destruction.

Adoptive Transfer↗

Psychopathology and the binding problem.

Normal cerebral activity is based on the rapid and flexible alternation of an enormous quantity of spatial-temporal patterns of neuronal firing. There is still much to learn about the mechanism that keeps neurons on functionally closed assemblies firing in synchronization. The explanation of this mechanism is the so called 'binding problem', one of the cornerstones of the generation of perceptions, cognitions, emotions and behaviours by the brain, and therefore of great interest to psychiatry. We explore the possibility that a 'binding dysfunction' could be a relevant aspect of the pathophysiology of mental disorders, and apply it to schizophrenia, in an attempt to integrate some neurobiological findings in this disorder, including a few preliminary data obtained with transcranial magnetic stimulation (TMS).

Brain↗

Targeting of nasal mucosa-associated antigen-presenting cells in vivo with an outer membrane protein A derived from Klebsiella pneumoniae.

Administration of vaccines by the nasal route has recently proven to be one of the most efficient ways for inducing both mucosal and systemic antibody responses in experimental animals. Our results demonstrate that P40, a well-defined outer membrane protein A from Klebsiella pneumoniae, is indeed a carrier molecule suitable for nasal immunization. Using fragments from the respiratory syncytial virus subgroup A (RSV-A) G protein as antigen models, it has been shown that P40 is able to induce both systemic and mucosal immunity when fused or coupled to a protein or a peptide and administered intranasally (i.n.) to naive or K. pneumoniae-primed mice. Confocal analyses of nasal mucosa-associated lymphoid tissue after i.n. instillation of P40 showed that this molecule is able to cross the nasal epithelium and target CD11c-positive cells likely to be murine dendritic cells or macrophages. More importantly, this targeting of antigen-presenting cells following i.n. immunization with a subunit of the RSV-A molecule in the absence of any mucosal adjuvant results in both upper and lower respiratory tract protection against RSV-A infection.

Adjuvants, Immunologic↗

Different types of contractions in rat colon and their modulation by oxidative stress.

The aim of this study was to investigate the modulation of in vitro rat colonic circular muscle contractions by dextran sodium sulfate (DSS)-induced inflammation and in spontaneous inflammation in HLA-B27 rats. We also examined the potential role of hydrogen peroxide (H(2)O(2)) in modulating excitation-contraction coupling. The muscle strips from the middle colon generated spontaneous phasic contractions and giant contractions (GCs), the proximal colon strips generated primarily phasic contractions, and the distal colon strips were mostly quiescent. The spontaneous phasic contractions and GCs were not affected by inflammation, but the response to ACh was suppressed in DSS-treated rats and in HLA-B27 rats. H(2)O(2) production was increased in the muscularis of the inflamed colon. Incubation of colonic muscle strips with H(2)O(2) suppressed the spontaneous phasic contractions and concentration and time dependently reduced the response to ACh; in the middle colon, it also increased the frequency of GCs. We conclude that H(2)O(2) mimics the suppression of the contractile response to ACh in inflammation. H(2)O(2) also selectively suppresses phasic contractions and increases the frequency of GCs, as found previously in inflamed dog and human colons.

Animals↗

Neural regulation of in vitro giant contractions in the rat colon.

The rat middle colon spontaneously generates regularly occurring giant contractions (GCs) in vitro. We investigated the neurohumoral and intracellular regulation of these contractions in a standard muscle bath. cGMP content was measured in strips and single smooth muscle cells. The circular muscle strips generated spontaneous GCs. Their amplitude and frequency were significantly increased by tetrodotoxin (TTX), omega-conotoxin, N(omega)-nitro-L-arginine (L-NNA), and the dopamine D(1) receptor antagonist Sch-23390. The GCs were unaffected by hexamethonium, atropine, and antagonists of serotonergic (5-HT(1--4)), histaminergic (H(1--2)), and tachykininergic (NK(1--2)) receptors but enhanced by NK(3) receptor antagonism. The guanylate cyclase inhibitor 1H-[1,2,4]oxidiazolo[4,3-a]quinoxalin-1-one (ODQ) also enhanced GCs to the same extent as TTX and L-NNA, and each of the three agents prevented the effects of the others. GCs were abolished by electrical field stimulation, S-nitroso-N-acetyl-penicillamine, and 8-bromo-cGMP. BAY-K-8644 and apamin enhanced the GCs, but they were abolished by D-600. Basal cGMP content in strips was decreased by TTX, L-NNA, or ODQ, but these treatments had no effect on cGMP content of enzymatically dissociated single smooth muscle cells. We conclude that spontaneous contractions in the rat colonic muscle strips are not generated by cholinergic, serotonergic, or histaminergic input. Constitutive release of nitric oxide from enteric neurons sustains cGMP synthesis in the colonic smooth muscle to suppress spontaneous in vitro GCs.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

A new species of sucking louse (Insecta, Anoplura) parasitic on Auliscomys (Mammalia, Rodentia) in Argentina.

Hoplopleura auliscomydis n. sp. is described based on specimens collected from Auliscomys micropus (Waterhouse 1837), from Collń Curá, Neuquén Province, Argentina. Descriptions are provided for the holotype male, female, first nymphal instar, external architecture of eggs (by scanning electron microscopy), and sites of oviposition, providing differences from its close relative Hoplopleura neotomydis Castro, González, and Cicchino, 1995. The geographical ranges of these 2 species are restricted to the Neuquén Province in Argentina. A key to the 9 species of the Hoplopleura travassosi species-group recorded in Argentina is also given.

Animals↗

Lipid and protein composition at different developmental stages of Pediculus capitis (Arthropoda, Phthiraptera).

Protein and lipid compositions were studied at different developmental stages of Pediculus capitis De Geer 1778. Phosphatidylcholine was found to be the predominant lipid at all stages and in both sexes. Palmitic and oleic acids were the main fatty acids throughout the 3 stages studied. A marked decline was observed in the total lipid content and triacylglyceride concentration during development, suggesting that their consumption is an energy source. The electrophoretic mobility revealed the predominance of a 320-kDa protein in eggs and adult females, whereas 2 major proteins of 514 and 439 kDa were found in nymphs, as well as in male and female adults. Two very high density lipoprotein fractions were isolated by ultracentrifugation of egg cytosol in a density gradient of NaBr. Both reserve lipoproteins contained phospholipids and triacylglycerols as the predominant lipids and a protein band of around 320 kDa. The structure of this band is likely to be similar to that found in females in a vitellogenic state.

Animals↗

Health status and health-related quality of life in survivors of cancer in childhood in Latin America: a MISPHO feasibility study.

Cancer is an increasing cause of disease-related death in childhood within developing countries, where the great majority of the world's children reside. The improving prospects for survival in such children, and the corresponding challenge of undertaking economic evaluations of related health interventions, provide a stimulus to study the health-status and health-related quality of life in survivors of cancer in childhood in Latin America. Spanish language versions of questionnaires for proxy assessors, based on the Health Utilities Index (HUI), were used to elicit responses from parents and physicians. The HUI is a family of multi-attribute, generic, preference-linked measures of health status and health-related quality of life that are reliable, responsive and valid, and have been used previously in pediatric oncology. Valid responses were received from 178 parents and 144 physicians in 6 centres in 4 countries (Cuba, Honduras, Colombia and Uruguay). For children with acute lymphoblastic leukemia the major morbidity burdens were in the attributes of emotion, cognition and pain. The overall burden of morbidity was greater in children with non-Hodgkin's lymphoma. In survivors of Hodgkin's disease and Wilms' tumor the attributes most affected were emotion and pain. In general, there was considerable agreement between the assessments provided independently by parents and physicians. This study demonstrates the feasibility of conducting such measurements in developing countries, and reveals similarities in health status and health-related quality of life to comparable populations in more privileged societies.

Child↗

Regulated heat shock protein 27 expression in human retinal pigment epithelium.

PURPOSE: To examine the expression and regulation of an injury-related protein, heat shock protein (Hsp) 27, in retinal pigment epithelium (RPE), since RPE injury may be an important feature of age-related macular degeneration (ARMD). METHODS: Retinal cross sections from eyes of Lewis rats were examined for Hsp27 in vivo by immunohistochemistry, and in vitro expression of Hsp27 in human ARPE-19 cells was determined by Northern and Western blot analysis. Oxidant-mediated injury was performed by exposing ARPE-19 cells to myeloperoxidase and hydrogen peroxide. Cell lines stably expressing green fluorescent protein (GFP) targeted to the cell membrane were used to study injury-induced membrane blebbing, and XTT conversion was used to detect cell viability. RESULTS: High level of Hsp27 expression was detected in vivo in ganglion cells, RPE, and photoreceptor outer segments of rat retina. ARPE-19 cells also expressed high levels of Hsp27 in vitro. Oxidative injury in ARPE-19 cells resulted in transcriptional and translational activation of Hsp27 and induced extensive membrane blebbing. A high level of Hsp 27 protein was detected within membrane blebs. Increased expression of Hsp27 was also observed in differentiated ARPE-19 cells when compared with dividing cells. Higher Hsp27 levels in differentiated RPE cells correlated with increased viability and phenotypically different blebbing after exposure to the injury stimulus. In addition, sublethal injury doses caused a moderate amount of membrane blebbing, which was well tolerated by differentiated ARPE-19 cells. CONCLUSIONS: These results indicate that Hsp27 may be an important component of the RPE injury response and may contribute to injury-induced membrane blebbing in differentiated RPE cells. It is hypothesized that Hsp27 levels may play a role in disease states in the retina, such as ARMD.

Animals↗

Camphor-based alpha-bromo ketones for the asymmetric darzens reaction

(1R)-2-endo-Bromoacetyl-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol (endo-2-bromoacetylisoborneol) 4 and its trimethylsilyl ether 3 are presented as efficient reagents for the asymmetric Darzens reaction. From the alpha,beta-epoxy ketone adducts the chiral inductor camphor is removed, by treatment with ceric(IV) ammonium nitrate, to yield the corresponding epoxy acids which are isolated as their dicyclohexylammonium salts.

Journal Article↗

The evaluation and treatment of the overweight patient.

Obesity represents one of the most important treatable causes of mortality and morbidity facing the primary care physician. Approximately one of every three U.S. adults is overweight or obese, leading to more than 300,000 preventable deaths each year. Because it is a multifactorial disorder involving food intake, physical activity, metabolism, and genetic factors, obesity is best treated with a coordinated approach. Diet and exercise remain the best initial treatment focus. Orlistat and sibutramine are recently developed medications reserved for obese patients who fail conservative therapy. Surgical remedies are indicated in limited circumstances for morbidly obese individuals. As primary care physicians, obstetrician/gynecologists are ideally positioned to motivate, evaluate, and treat overweight patients.

Journal Article↗

Coitus-induced activation of c-fos and gonadotropin-releasing hormone in hypothalamic neurons in female rabbits.

Copulation induces hypothalamic release of neuropeptides and catecholamines, especially gonadotropin-releasing hormone (GnRH) and norepinephrine, in female rabbits. The forebrain distribution of GnRH cells and the cellular events responsible for the coitally induced GnRH surge have not been identified. We characterized the expression of c-fos mRNA before (0 min) and up to 60 min after coitus in forebrain tissues of mated and nonmated females and compared these findings with those in which single- and double-labeled GnRH/Fos protein cells were identified by immunocytochemistry (ICC). Enhanced expression of fos-mRNA occurred 30 min after coitus, especially in the anteroventral periventricular nucleus (AVPV), the encapsulated portion of the bed nucleus of the stria terminalis (BNSTe) and the ventrolateral hypothalamus (VLH); this increased fos-mRNA activity remained elevated at 60 min in the AVPV and VLH, and was reflected by Fos protein expression 90 min postcoitus. Both ICC Fos-labeled and ICC GnRH-labeled cells were widely distributed throughout the forebrain with postcoital increased double-labeling in the preoptic-septal areas, the anterior-medial hypothalamus and the VLH. The increased number of dual-labeled and unchanged number of single-labeled GnRH cells after coitus suggest some GnRH neurons were non-detected before coitus. Many dual-labeled neurons were adjacent to Fos-labeled cells, suggesting enhanced interneuronal input to GnRH cells after coitus. Collectively, the results suggest that coitus activates hypothalamic GnRH neurons via several loci that include the AVPV, BNSTe and VLH. The distinct anatomical location of the AVPV, BNSTe and VLH further suggests that coital signals may reach the hypothalamus via separate neural pathways that are likely developed within the brainstem.

Animals↗

Impact of protease inhibitor therapy on HIV-related oropharyngeal candidiasis.

OBJECTIVE: To determine the relationship between antiretroviral therapy and changes in prevalence and amount of oropharyngeal candidiasis (OPC) and skin test reactivity for delayed type hypersensitivity. DESIGN: Observational cohort. SETTING: University-based public hospital AIDS clinic. PATIENTS: Adults with advanced HIV infection who had been taking nucleoside transcriptase inhibitor drugs but had not taken a protease inhibitor and who started antiretroviral treatment with ritonavir. MAIN OUTCOME MEASURES: OPC lesions score, oral candidal colonization, oral candidal quantification, skin test reactivity for delayed type hypersensitivity (purified protein derivative, candidal and streptokinase antigens), plasma HIV RNA and CD4 cell count at weeks 8, 16 and 48 weeks. RESULTS: In the 99 patients who entered the study, there was a significant reduction in the HIV plasma RNA (mean log decrease from baseline at 48 weeks 0.88) and a significant increase in CD4 cell counts (mean CD4 cell increase from baseline at 48 weeks 128 x 10(6) cells/l). Only 17% of patients had < 200 copies/ml HIV RNA at 48 weeks. There were significant decreases in the prevalence of OPC lesions (31% at baseline to 1% at 48 weeks; P < 0.001), and in oral candidal loads [2226 to 811 colony-forming units (CFU)/ml; P = 0.0171]. The percentage of patients with at least one positive skin test increased significantly (6 to 28%; P < 0.05). Patients whose CD4 lymphocyte count was > 200 x 10(6) cells/l at 48 weeks had significantly lower oral candidal loads and were more likely to have a positive skin test than patients whose CD4 cell count was < 200 x 10(6) cells/l. CONCLUSION: In patients with advanced HIV infection, antiretroviral treatment including a protease inhibitor has a positive impact in the natural history of OPC. This positive impact appears to be correlated with a better immunological function and occurs despite continuous HIV replication.

AIDS-Related Opportunistic Infections↗

Distribution of the mRNA encoding the four dopamine D(1) receptor subtypes in the brain of the european eel (Anguilla anguilla): comparative approach to the function of D(1) receptors in vertebrates.

Four subtypes of D(1) dopamine receptors are expressed in the brain of the European eel (Anguilla anguilla), an elopomorph teleost. To correlate this molecular multiplicity with specific localisation and functions, the distribution of the D(1) receptor transcripts was analysed by in situ hybridisation. The four D(1) receptor transcripts exhibit largely overlapping expression territories. In telencephalon, they are found in the olfactory bulb and the dorsal telencephalon (except its lateral part) but are most abundant in the subpallial areas. More caudally, the entopeduncular nucleus, preoptic nuclei, preglomerular nuclear complex, ventral thalamus, periventricular hypothalamus, optic tectum and cerebellum, all contain various amounts of D(1) receptor transcripts. Finally, D(1) receptor mRNAs are present in nuclei associated with the cranial nerves. The two D(1A) receptor subtypes are generally the most abundant and present a different distribution in several areas. The D(1B) mRNA, although present in fewer areas than D(1A) transcripts, is the most abundant in ventrolateral telencephalon and torus semicircularis. The D(1C) receptor transcript, which has not been found in mammals, is restricted to diencephalon and cerebellum. In view of the expression territories of D(1) receptor transcripts and previous data, some areas of the everted telencephalon of teleost may be homologous to regions of the tetrapod brain. In particular, D(1) expression territories of the ventral telencephalon are likely to be equivalent to striatal areas. These observations suggest an evolutionary scenario in which the D(1A) receptor subtype was highly conserved after the first gene duplication during the evolution of craniates, whereas D(1B) and D(1C), and their associated specific characteristics, appeared later, probably in the gnathostome lineage.

Anguilla↗

Density-functional theory of inhomogeneous fluids in the canonical ensemble

We present a density-functional approach for dealing with inhomogeneous fluids in the canonical ensemble. A general relation is proposed between the free-energy functionals in the canonical and the grand canonical ensembles. The minimization of the canonical-ensemble free-energy functional gives rise to Euler-Lagrange equations which involve averaged Ornstein-Zernike equations of second and third order. The theory is especially appropriate for systems with a small, fixed number of particles. As an example of application we obtain accurate results for the density profile of a hard-sphere fluid in a closed spherical cavity that contains only a few particles.

Journal Article↗

Low serum promotes maturation of excitation-contraction coupling in myotubes.

Patch-clamping and the simultaneous fluorescence measurement of cytoplasmic Ca2+ ([Ca2+]i) were used to analyze the effect of serum on the functional features of excitation-contraction (E-C) coupling in mouse skeletal myotubes. In high-serum-treated (10%) myotubes, depolarization elicited Ca2+ release which continued for tens of milliseconds following the end of the pulse, after which [Ca2+]i decayed slowly. In low-serum-treated (0.5%) myotubes, the Ca2+ transient caused by depolarization had an increased rate of rise and peak amplitude, and [Ca2+]i began to decay rapidly upon repolarization. When a depolarizing pulse (0.5-1.0 s) was applied to low-serum-treated myotubes during a Ca2+ transient induced by 5-10 mM caffeine, repolarization usually caused the caffeine transient to terminate rapidly (RISC; repolarization-induced stop of caffeine-induced Ca2+ release). The RISC was less prominent in high-serum-treated myotubes. These results suggest that low serum promotes the maturation of myotubes so that Ca(2+)-release and Ca(2+)-removal activities are accelerated. Additionally, the essential features of the communication between the voltage sensor and the Ca(2+)-release channel are shared by myotubes and adult muscle fibers.

Age Factors↗