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Biomedical subjects

D Reis

Publications and source records attributed to D Reis.

At least 19 recordsLinked to original sources
PubMed2001

Nurses' perceptions of complementary and alternative medical therapies.

The purpose of this study was to identify the perceptions of nurses toward the effectiveness and safety, as well as their recommendations for and personal use of complementary and alternative medical therapies. A, random sample of 1000 nurses throughout the United States were surveyed using a three-wave mailing. About half of the respondents perceived there was conclusive evidence or preponderance of evidence that five therapies were effective: biofeedback, chiropractic, meditation/relaxation, multi-vitamins, and massage therapy. The same amount of nurses also perceived five therapies as definitely safe: hypnotherapy, chiropractic, acupressure, acupuncture, and healing touch. However, the nurses were most likely to recommend (regularly or periodically) four therapies: multivitamins, massage, meditation/relaxation, and pastoral/spiritual counseling. The vast majority (79%) of nurses perceived their professional preparation in this area to be fair or poor.

Adult↗
PubMed2001

Myosin V and iNOS expression is enhanced in J774 murine macrophages treated with IFN-gamma.

Actin-based motor protein requirements and nitric oxide (NO) production are important features of macrophage activity during phagocytosis or microbicidal processes. Different classes of myosins contribute directly or indirectly to phagocytosis by providing mechanical force for phagosome closure or organelle movement. Recent data have shown the presence of myosins IC, II, V and IXb in phagosomes of bone marrow-derived murine macrophages. In our investigation we demonstrated the presence of different classes of myosins in J774 macrophages. We also analyzed the effect of gamma interferon (IFN-gamma), with or without calcium ionophore or cytochalasin B, on myosins as well as on inducible nitric oxide synthase (iNOS) expression and NO production. Myosins IC, II, Va, VI and IXb were identified in J774 macrophages. There was an increase of myosin V expression in IFN-gamma-treated cells. iNOS expression was increased by IFN-gamma treatment, while calcium ionophore and cytochalasin B had a negative influence on both myosin and iNOS expression, which was decreased. The increases in NO synthesis were reflected by increased iNOS expression. Macrophages activated by IFN-gamma released significant amounts of NO when compared to control groups. In contrast, NO production by calcium ionophore- and cytochalasin B-treated cells was similar to that of control cells. These results suggest that IFN-gamma is involved in macrophage activation by stimulating protein production to permit both phagocytosis and microbicidal activity.

Animals↗
PubMed2000

Imidazoline receptor proteins are decreased in the hippocampus of individuals with major depression.

BACKGROUND: A downregulation of I(2)-imidazoline binding sites has been reported in frontal cortices of depressed suicide victims, according to I(2)-radioligand binding and confirmed by Western blotting. We now report Western blots of imidazoline receptor proteins in hippocampi of subjects with and without depression at the time of death. METHODS: Postmortem diagnoses were obtained from 17 cases of Axis I major depressive disorder and 17 cases without Axis I psychopathology. No psychotropic compounds were found in body fluids. Hippocampi were removed, sectioned, and assessed histologically. Throughout the analysis, each major depressive disorder sample was paired with a sample from a psychiatrically healthy subject based on equivalent life spans and postmortem delays. The antiserum was identical to that used in previous studies that reported a downregulation of cortical 29/30-kd imidazoline receptor-binding proteins in depression. RESULTS: A triad of imidazoline receptor-binding protein bands (40-50 kd) was detected in the human hippocampus. Subjects with major depressive disorder had significantly less intensity in each imidazoline receptor-binding proteins band compared with control subjects (p =. 01 for overall bands). CONCLUSIONS: The present results can be aligned with previous reports of downregulation of I(2)-radioligand binding sites in both cortices and platelets of depressed patients.

Adult↗
PubMed1999

Treatment of experimental avascular necrosis of the femoral head with hyperbaric oxygen in rats: histological evaluation of the femoral heads during the early phase of the reparative process.

The healing of vascular deprivation-induced necrosis of the femoral head of rats exposed to hyperbaric oxygen was compared with that in untreated rats. The amount of necrotic bone, extent of osteoneogenesis, degree of remodeling, and changes of the articular cartilage were histologically graded on a semiquantitative scale of 0 to 3+. On the 2nd, 7th, and 21st postoperative days, there were no differences between the two groups. Newly formed appositional and intramembranous bone was more abundant and remodeling was more advanced in the femoral heads of the hyperbaric oxygen-treated than untreated rats sacrificed on the 42nd postoperative day; also there was less necrotic debris in the femoral heads of the treated rats. There were no differences in the severity of the degenerative changes of the articular cartilage of the treated and untreated rats. Exposure of rats to hyperbaric oxygen does not preserve tissue viability after all arteries supplying the femoral head are severed. Yet, resulting in an increased oxygen tension of the tissues, it seems to provide the optimal settings for reparative processes. The results suggest that hyperoxygenation-mediated relief of ischemia enhances the fibroblastic, angioblastic, osteoblastic, and osteoclastic activities such that healing of the rats' necrotic femoral heads is expedited.

Animals↗
PubMed1999

Expression of the ferrioxamine receptor gene of Erwinia amylovora CFBP 1430 during pathogenesis.

Mutants of Erwinia amylovora CFBP 1430 lacking a functional high-affinity iron transport system mediated by desferrioxamine are impaired in their ability to initiate fire blight symptoms (A. Dellagi, M.-N. Brisset, J.-P. Paulin, and D. Expert. Mol. Plant-Microbe Interact. 11:734-742, 1998). In this study, a chromosomal transcriptional lacZ fusion was used to analyze the expression in planta of the E. amylovora ferrioxamine receptor gene foxR. LacZ activity produced by the strain harboring the fusion was highly induced in iron-restricted conditions and in inoculated apple leaf tissues. Microscopic observation revealed differential expression of this gene in relation to the localization and density of bacterial cells within the diseased tissue. Thus, the ability of bacterial cells to express their iron transport system in accordance with environmental conditions is likely important for disease evolution.

Artificial Gene Fusion↗
PubMed1999

Hyperglycemia-induced embryonic dysmorphogenesis correlates with genomic DNA mutation frequency in vitro and in vivo.

Congenital malformations affecting multiple organ systems are at least three times more common in infants of mothers with IDDM than in infants born to nondiabetic mothers. Numerous studies have confirmed the teratogenic effect of hyperglycemia on the developing embryo, although no direct mechanism has been determined. In this study, we aimed to correlate the frequency of lacI mutations with degree of hyperglycemic exposure and severity of malformations in mouse embryos from in vitro cultures. Day 8 transgenic mouse embryos cultured in 30 or 50 mmol/l glucose for 48 h exhibited a higher incidence of morphological abnormalities, as well as an increase in lacI mutation frequency, compared with embryos cultured in 10 mmol/l glucose with no abnormalities and a lower frequency of lacI mutations. We also used a transgenic lacI rat system to evaluate the relationship between abnormal embryonic development and DNA mutation frequency in day 11 embryos of severely diabetic rats (serum glucose >20 mmol/l). Compared with control embryos, the embryos from diabetic rats displayed significantly more malformations, shorter crown-rump lengths, fewer somites, and more than six times greater genomic DNA mutation frequency. Genetic analysis of the mutated lacI gene from both in vitro cultured mouse embryos and in vivo developed rat embryos revealed that the majority of mutations were due to base substitutions (transitions and transversions), but that the rate of large DNA mutations tended to increase in embryos exposed to a diabetic environment. Our results support the interrelationship between increased rates of congenital malformations and DNA mutations in the offspring of diabetic pregnancy.

Animals↗
PubMed1998

Decreased CD4(+) circulating T lymphocytes in patients with gastrointestinal chagas disease.

The gastrointestinal form of Chagas disease is characterized by lumenal enlargement and wall thickening of the esophagus and/or colon. Very little is known about the involvement of the immune system in the development of the gastrointestinal form of the disease. In this paper we describe our initial observations on the phenotypic analysis of peripheral blood mononuclear cells from patients with the gastrointestinal form of Chagas disease. A significant decrease in the absolute number of CD3(+) T cells as well as in CD19(+) B lymphocytes was observed. However, the most striking observation was an inversion of the CD4/CD8 ratio, contrasting with results from cardiac chagasic patients in whom the ratio is normal. A decrease of the percentage of CD4(+)CD28(+) cells and an increase in the expression of HLA-DR both on CD4(+) and on CD8(+) cells suggest that although these T cells express activation markers their function may be altered by the lack of CD28 expression.

Adult↗
PubMed1998

Vascular deprivation-induced necrosis of the femoral head of the rat. An experimental model of avascular osteonecrosis in the skeletally immature individual or Legg-Perthes disease.

The blood supply of rats' femoral heads was severed by cutting the ligamentum teres and stripping the periostium. Histologically, necrosis of the marrow was apparent on the 2nd postoperative day, necrosis of the bone on the 5th postoperative day and fibrous ingrowth on the 7th postoperative day. During the following 5 weeks, progressive resorption of the intertrabecular necrotic debris and necrotic bony trabeculae and subchondral bone plate and, concurrently, appositional and intramembranous new bone formation resulted in remodeling of the femoral heads. In 2 of 7 femoral heads, replacement of the necrotic bone by viable bone was complete at the 42-day postoperative interval. Also, the articular cartilage of the deformed and flattened femoral heads was undergoing degenerative changes. Reduplicating the pathogenically inferred clinical settings of blood supply deprivation, it is proposed that this model, in a small laboratory animal, satisfies the requirements sought for preclinical studies of treatment modalities of avascular osteonecrosis in man.

Animals↗
PubMed1997

DC electrical field-induced c-fos expression and growth stimulation in multicellular prostate cancer spheroids.

The effects of electrical direct current (DC) field pulses on c-fos expression, growth kinetics and vitality patterns of multicellular tumour spheroids (MCSs) were studied. Monitoring the membrane potential of MCSs by di-8-ANNEPS staining and confocal microscopy during DC electrical field treatment revealed a hyperpolarization at the anode-facing side and a depolarization at the cathode-facing side. When a single 500 V m(-1) electrical field pulse with a duration of 60 s was applied to MCSs (150-350 microm in diameter) an enhancement of the growth kinetics within a period of 6 days post pulse was observed. Whereas the volume doubling time amounted to 4-5 days in control samples, it was reduced to 1-2 days in electropulsed MCSs. At day 6 post pulse the diameter of the necrotic core was significantly smaller than the control. The critical diameter for the first appearance of central necrosis amounted to 350 +/- 50 microm in the control and 450 +/- 50 microm in the electropulsed MCSs. Coincidentally, the proliferating rim was increased to 107 +/- 11 microm in electropulsed MCSs as compared with 60 +/- 6 microm in the control. The growth stimulation may be mediated by the proto-oncogene c-fos as its expression increased by a factor of 2.5 within 2 h post pulse. c-fos expression declined towards control values within 8 h post pulse.

Buffers↗
PubMed1996

Neuropeptide Y receptor gene regulation in mouse adrenocortical Y-1 cells.

The mouse adrenocortical Y-1 cell line expresses a high level of neuropeptide Y1 receptor (NPY-Y1). Moreover the receptor density can be up-regulated by dexamethasone or down-regulated by cAMP. To determine whether such regulation occurs at the level of gene expression, Y1 receptor mRNA was measured using a reverse transcriptase-competitive PCR method. Dexamethasone treatment increased Y1 mRNA in Y-1 cells, whereas the cAMP and ACTH decreased it. We also observed that the amount of Y1 receptor RNA was unaffected by phorbol 12-myristate 13-acetate, a protein kinase C stimulator, but was abolished in a cell line expressing apolipoprotein E (apoE). The results indicated that NPY-Y1 receptor mRNA in Y-1 cells is highly regulated by several intracellular messengers. The role of apoE in such regulation is of particular interest in view of evidence that the isoform of the molecule is highly correlated to the age of onset of Alzheimer's disease. The effect observed in the Y-1 cell line which expresses apoE may implicate a possible role of this protein in the process of neuronal death that occurred in the Alzheimer's disease.

Adrenal Cortex↗
PubMed1996

Kinetoplast DNA signatures of Trypanosoma cruzi strains obtained directly from infected tissues.

We report here a polymerase chain reaction (PCR)-based DNA profiling technique that permits Trypanosoma cruzi strain characterization by direct study of infected tissues. This is based on application of a recently developed method of DNA fragment identification, called low-stringency single specific primer PCR (LSSP-PCR), to the study of the variable region of kinetoplast DNA (kDNA) minicircles from T. cruzi Thus, we can translate the intraspecific polymorphism in the nucleotide sequence of kDNA minicircles into a specific and highly reproducible kDNA signature. Comparison with the phenogram obtained by DNA fingerprinting analysis of a set of T. cruzi strains showed good qualitative correlation between the degree of divergence of the LSSP-PCR profiles and the genetic distance between the strains. kDNA signatures of heart tissue from acutely or chronically infected animals revealed perfect concordance with the patterns obtained from cultured parasites for the CL and Colombiana strains but not for the Y strain, which is known to be multiclonal. However, the match was perfect for studies with two clones of the Y strain. We take this as evidence that in some multiclonal strains there is heterogeneity among the clones in the degree of tropism for the heart tissue. Finally, we showed that it is possible to obtain a T. cruzi kDNA signature from the heart of a human patient with chronic Chagasic myocardiopathy. kDNA signatures obtained by LSSP-PCR of sequences amplified from infected tissues constitute a new tool to study the molecular epidemiology of Chagas' disease.

Animals↗
PubMed1995

Studies on neuropeptide Y receptors in a mouse adrenocortical cell line.

The mouse adrenocortical Y-1 cell line has been found to express high affinity binding sites for neuropeptide Y (NPY). Pharmacological studies have shown that these NPY binding sites are of the Y1 type. Reverse transcription-polymerase chain reaction using primers specific for the rat Y1 receptor revealed that the NPY Y1 receptor mRNA is present in Y-1 cells. The Kd of the receptor for NPY was found to be 1.75 +/- 0.20 nM and the Bmax was 265 +/- 18 fmol/mg. The NPY Y1 receptors in this adrenocortical cell line were shown to be coupled to pertussis toxin-sensitive G proteins. Stimulation of Y1 receptors resulted in the inhibition of forskolin- and adrenocorticotropic hormone (ACTH)-stimulated cAMP synthesis. NPY had no effect on basal steroid release from the Y-1 cells. At an ACTH concentration of 0.1 microM, NPY did not affect ACTH-stimulated steroid release, although NPY did inhibit cAMP production under the same hormonal conditions. cAMP profoundly affected the density of the NPY receptors in Y-1 cells. Treatment of the cells with N6,2'-O-dibutyryl-cAMP or ACTH reduced the Y1 receptor density by > 50%. On the other hand the steroid dexamethasone increased the density of Y1 receptors by 35%. Although additional detailed studies are necessary, these results may have interesting implications for the functions of ACTH, steroids, and NPY in the pituitary-adrenocortical axis.

Adrenal Cortex↗
PubMed1992

Interferon-neutralizing or enhancing activities in hybridoma cell fluids after in vitro immunization.

Several hybridomas supernatants capable of interferon beta (IFN-beta) or "IFN epsilon" ("IFN-eps") neutralizing or enhancing activities were obtained after in vitro immunization of BALB/c and C57 mice spleen cells and their fusion with Sp2/0 plasmacytoma cells. Besides rather low anti-IFN-beta or "eps" antibody secretion several cloned hybridoma fluids contained a factor potentiating anti-viral activity of the both IFNs. It is speculated that this activity is due to production by some hybridomas of another lymphokine.

Animals↗
PubMed1991

Liquid crystal-type assembly of native cellulose-glucuronoxylans extracted from plant cell wall.

In numerous plant cell walls, the cellulose microfibrils are arranged in a helicoidal pattern which has been considered as an analog to a cholesteric order. Here, we report on the spontaneous helicoidal organization which occurs in acellular conditions from aqueous suspensions of cellulose. The cellulosic mucilage of mature seeds of quince (Cydonia oblonga L) was studied both in situ (pre-release mucilage) and after water extraction and in in vitro re-assembly (prolonged high speed ultracentrifugation, further progressive dehydration and embedding in LR White methacrylate or hydrosoluble melamine resin). The cellulosic component was characterized by the use of cellobiohydrolase (CBH1) bound to colloidal gold, and the glucuronic acid residues of the xylan matrix were characterized by the use of cationised gold. Inside the seeds, the pre-release mucilage is mostly helicoidal, with the occurrence of more or less ordered domains, which indicate a fluid organization relevant to an actual liquid crystal state. Cytochemical tests revealed the tight association between cellulose and glucuronoxylans, the latter constituting a charged coat around each microfibril. Following the hydration of the seed, a cellulosic suspension was extracted in which microfibrils were totally dispersed. The progressive dehydration of the suspension gave rise to concentrated viscous drops. Ultrastructural observations revealed the occurrence of multidomain organization, from non-ordered to cholesteric-like regions, revealing that the mucilage is at the same time crystalline and liquid. This constitutes the first demonstration that liquid crystal type assemblies can arise from crystalline and biological cellulose in aqueous suspension. It strengthens the hypothesis that a transient liquid crystal state must occur during the cellulose ordering. The possible morphogenetic role of the glucuronoxylans in the cholesteric organization of the cellulose is discussed.

Cell Wall↗
PubMed1986

The role of novel inotropic agents in the treatment of heart failure.

While the acute hemodynamic efficacy and safety of the novel inotropic agents are well recognized, their long-term effects on symptoms, quality of life, and survival, in patients with chronic congestive heart failure, are controversial. Such controversy may result from a poor understanding of the disease process and its progression, unrealistic expectations on the potential benefits of enhancing myocardial contractility at an advanced stage of the disease, and the lack of knowledge of the precise mechanisms of action of the novel inotropic agents. To put into perspective the role of the novel inotropic agents in the treatment of chronic congestive heart failure, the effects of dobutamine (a synthetic catecholamine which is the most potent inotropic agent currently available) were reviewed. Changes in cardiac performance, myocardial contractility and metabolism, and exercise capacity were studied in patients with chronic congestive heart failure of variable severity. The acute hemodynamic effects and the mechanism of action of the novel inotropic agents were then reviewed and compared to those of dobutamine. Which patients with chronic congestive heart failure who are the most likely to benefit from therapy with the novel inotropic agents, and the therapeutic limitations of these agents are discussed. Lastly, the difficulties of selecting the right endpoints to demonstrate the long-term efficacy of the novel inotropic agents are considered.

Amrinone↗