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Biomedical subjects

M Garcia

Publications and source records attributed to M Garcia.

At least 181 records · Page 10Linked to original sources
PubMed1994

Acid aspiration prophylaxis in elective biliary surgery. A comparison of omeprazole and famotidine using manually aided gastric aspiration.

We have compared the effects of single oral doses of omeprazole 40 mg, famotidine 40 mg or placebo on gastric secretion in 45 non-obese patients the night before elective biliary surgery. After stable anaesthesia had been established, a Salem orogastric tube was introduced and gastric contents were aspirated by a blinded observer. The volume and pH were noted. After the abdomen was opened aspiration was repeated but on this occasion with the surgeon's manual assistance. We found that the initial aspirate volume underestimated total gastric volume by an average (SD) of 7.1 (6.6) ml. Famotidine, but not omeprazole, produced a significant decrease in gastric volume and acidity. Patients were considered to be at risk if pH < 2.5 and volume > 0.4 ml.kg-1. Three patients in the omeprazole group, three in the placebo group and none in the famotidine group came into this category. We conclude that a single oral dose of omeprazole 40 mg given the night before surgery does not afford adequate prophylaxis for acid aspiration syndrome.

Adult↗
PubMed1994

Body mass index and economic productivity.

The paper reviews the evidence to date on the nutritional links with productivity and then goes on to provide results from a multi-country study on the effects of increasing body mass index (BMI) on productivity. The research relating nutritional status to work capacity is more consistent than the research linking nutritional status to productivity. None of the studies to date elucidate the pathways through which improved nutrition improves economic productivity. In addition, many of the studies that have been conducted on the nutrition/wage links have been based on samples that contained a disproportionate number of male subjects. The few studies that have disaggregated data by gender report different results for men and women. Research conducted at IFPRI is presented to examine the trends in BMI for men and women across countries and for Kenya to examine the relationships between various measures of nutritional status--BMI and height--and energy expenditures in women. BMIs of men show a more consistent relationship with increasing household income than do the BMIs of women. In the case of the Gambia and Kenya, the mean BMI of women decreases with increasing household income. One reason for the apparently low response of BMI to increasing household income in Kenya is the time allocation patterns of women. Women in the Kenya sample spend the largest proportion of their day in home production activities which are energy intensive. In examining the relationship between nutritional indicators and the time devoted to work, the results suggest a significant, positive association between both BMI and height and the amount of time devoted to work. In the models presented, both BMI and height appear to increase the capacity to carry out work. It is difficult to value much of this work time since a disproportionate share is devoted to home production activities. Some of the more classic methods of measuring economic productivity, such as measuring wage rates, are not relevant for women in this setting. The data from Kenya suggest that more appropriate measures for specifying the value of women's work need to be developed in order to capture some of the nutrition/productivity links which may exist.

Body Mass Index↗
PubMed1994

Assessing the linkages between low body mass index and morbidity in adults: evidence from four developing countries.

The study explores the relationship between low BMI and illness patterns in four developing countries. Using probit analysis, the study finds small but statistically significant effect of low BMI on proneness to morbidity in Pakistan and Kenya but none in the Philippines and Ghana. The circularity of causation between low BMI and illness was addressed by using the instrumental variable approach. The study also finds that the threshold at which morbidity begins to rise is not consistent with the suggested cut-off of BMI 18.5 kg/m2. The cut-offs were meaningful only in the case of Pakistan, but even here, the sizes of relationships are quite small although statistically significant.

Adolescent↗
PubMed1994

Atrial septal aneurysm as a potential source of neurological ischemic events.

An atrial septal aneurysm (ASA) is a congenital malformation of the atrial septum characterized by bulging of the septum overlying the fossa ovalis region into either atrium. The prevalence of ASA varies according to the diagnostic method used and to the type of population studied. A practical classification of ASA based on the current knowledge of its pathogenesis into Type I, Type II, and Type III is presented. With the widespread use of transesophageal echocardiography in recent years, ASA has become an increasingly recognized entity. Recently, the clinical interest in ASA has been increased by several reports in the literature proposing ASA as a potential source of emboli. The three most plausible mechanisms to link this association are thrombus formation in or around the ASA, paradoxical embolization through an interatrial communication in the form of patent foramen ovale or atrial septal defect, and mitral valve prolapse that has been found to be frequently associated with ASA. Although the echocardiographic detection of ASA is in most cases an incidental finding, the identification of ASA should prompt careful review of the echocardiogram for mitral valve prolapse, atrial septal defect, and patent foramen ovale. Although conclusive evidence of a causal relation between ASA and cerebrovascular emboli has not been shown, the identification of ASA in such patients in the absence of another cause to explain the embolic event may represent an indication for long-term antiplatelet or anticoagulation therapy, or even surgery. Until long-term follow-up results of these patients are available, management should be on an individual basis.

Adult↗
PubMed1994

Cathepsin D maturation and its stimulatory effect on metastasis are prevented by addition of KDEL retention signal.

Cathepsin D is overexpressed in most primary breast cancers where its concentration is correlated with increased metastatic potential. To investigate the possible role and mechanism of this lysosomal protease in metastasis, we transfected low-metastatic rat tumor cells with wild-type human cathepsin D, or mutated forms obtained by insertion of a KDEL peptide signal responsible for ER retention, or a control KDAS peptide. The overexpressed pro-cathepsin D in wild-type and KDAS clones was normally sorted and maturated in lysosomes. In KDEL clones, pro-cathepsin D was mostly retained in the ER or partially secreted by high-producer clones but was not maturated. While overexpressed cathepsin D increased experimental metastasis in athymic mice, the pro-cathepsin/D-KDEL was totally ineffective. Moreover, the effect of cathepsin D on metastasis did not seem to be due to saturation of the mannose-6-phosphate receptor since the secretion of two other rat lysosomal enzymes was unaffected by cathepsin D overexpression. We conclude that pro-cathepsin D overexpression facilitates tumor metastasis only when maturated into an active enzyme.

Amino Acid Sequence↗
PubMed1993

Genomic organization and expression of two independent gene arrays coding for two antigenic acidic ribosomal proteins of Leishmania.

In the present paper we describe the isolation and characterization of four novel genes of the parasitic protozoan Leishmania infantum. These genes are organized as two independent gene clusters, and they are related by nucleotide sequence to eukaryotic genes encoding acidic ribosomal proteins. Each gene cluster contains two tandemly linked genes coding for identical proteins. Each of the proteins coded by the gene clusters (called LiP and LiP') are highly divergent in sequence, showing the characteristic features of eukaryotic P-proteins from the P2 group. In spite of the sequence conservation of the coding regions of each of the genes in the cluster, the 5'- and 3'-untranslated regions are heterogeneous in sequence. The analysis of the expression of these genes indicates that logarithmic phase promastigotes show increased levels of LiP- and LiP'-specific transcripts compared with stationary phase promastigotes. The steady state RNA levels of the LiP and LiP' genes show a similar dependence of the growth phase of the parasite. Using specific probes for the divergent 3'-untranslated regions of each of the genes, it was found that the abundance of the mature transcripts is different even when the transcripts are derived from the same gene cluster. These findings probably indicate that the 3'-untranslated regions may influence the stability or turnover of the transcripts derived from both LiP and LiP' gene clusters.

Amino Acid Sequence↗
PubMed1993

v-jun cooperates with v-erbB to transform the thrombocytic/megakaryocytic lineage.

The transforming properties of v-jun, the viral counterpart of the transcription factor AP1, were investigated in avian hematopoietic cells. Two retroviruses, called JB and JBN, expressing both v-jun and v-erbB, were constructed using an avian erythroblastosis-based vector. We show that the cooperative action of both oncogenes allowed the virus to efficiently transform bone marrow cells. No such transformation was obtained with either oncogene alone. JB-transformed bone marrow cells expressed GATA-1, TAL-1, and histone H5, suggesting that they belong to the erythrocytic/thrombocytic lineage. (Thrombocytes are the avian homologues of mammal megakaryocytes.) Moreover, after induction with phorbol 12-myristate 13-acetate JB-transformed bone marrow cells began to differentiate and synthesized high levels of platelet glycoproteins, indicating that they were of thrombocytic origin. These results were confirmed by c-ets1 analysis since this transcription factor, specifically found in cells with megakaryocytic but not erythrocytic features, was clearly detected in these cells.

Animals↗
PubMed1993

Ricin-resistant Madin-Darby canine kidney cells missort a major endogenous apical sialoglycoprotein.

gp114 is a major sialoglycoprotein expressed on the apical membrane of Madin-Darby canine kidney (MDCK) II cells. We investigated its distribution in two lectin-resistant mutant cell lines derived from MDCKII cells, MDCKII-RCAr and MDCKII-ConAr cells. gp114 was present on the apical membrane of MDCKII-ConAr cells but was predominantly basolateral in MDCKII-RCAr cells. No change of polarity was observed for several apical and basolateral markers in this cell line. Reversal of polarity of gp114 mainly resulted from a modification of its intracellular sorting. gp114 showed altered endocytosis in MDCKII-RCAr cells. In MDCKII cells gp114 was slowly endocytosed, whereas in MDCKII-RCAr cells endocytosis of gp114 was highly increased. Using mannosidase I and II inhibitors we found that N-glycosylation only slightly affects gp114 sorting and endocytosis. Our results suggest that gp114 or an associated component in MDCK-RCAr fails to express apical information or that a mutation creates a basolateral sorting signal which could be related to endocytic signals.

Animals↗
PubMed1993

Syndrome of Rochalimaea henselae adenitis suggesting cat scratch disease.

OBJECTIVE: To describe a clinical syndrome of cat scratch disease caused by Rochalimaea henselae, including methods for isolation of the organism from tissue and for identification. DESIGN: Case series. SETTING: U.S. Air Force referral hospital infectious diseases clinic. PATIENTS: Two previously healthy patients. MAIN MEASUREMENTS AND RESULTS: Two immunocompetent patients who had handled cats developed unilateral upper-extremity adenitis associated with a distal papular lesion and fever. The adenitis and distal lesions persisted and progressively worsened. Cultures of the involved lymph nodes from both patients grew R. henselae, a recently described organism associated with bacillary angiomatosis and peliosis hepatis in human immunodeficiency virus-infected patients and with bacteremia in immunocompromised and immunocompetent hosts. The organism was characterized as oxidase negative and X-factor dependent and had a characteristic pattern in analysis of whole-cell fatty acids differing from Afipia felis, a bacterium that has been associated with cat scratch disease. The identity of the isolate was confirmed by analysis of whole-cell fatty acids using gas chromatography and by amplification of the citrate synthetase gene sequence and analysis of the polymerase chain reaction-amplified product. The organisms were broadly susceptible to a variety of antimicrobials by broth microdilution; however in-vitro resistance to first-generation cephalosporins correlated with clinical failure of therapy. CONCLUSION: Rochalimaea henselae can be a cause of cat scratch disease in immunocompetent patients.

Adult↗
PubMed1993

Effects of Policosanol on platelet aggregation in rats.

Policosanol is the trivial name of a mixture of high molecular weight alcohols isolated from sugar cane, wherein octacosanol is the main component. The effects of Policosanol treatment on rat platelet aggregation were studied. Depending on the dose, Policosanol (5-20 mg/kg, perorally) inhibited the decrease in circulating platelet counts and collagen-induced malondialdehyde concentration in plasma. In rat clotted whole blood thromboxane B2 formation was inhibited by Policosanol (25 mg/kg). Policosanol (50-200 mg/kg, single doses) inhibited ADP-induced platelet aggregation in platelet-rich plasma, while lower doses (25 mg/kg) did not change responses to ADP significantly. However, rats treated with this dose (25 mg/kg) for 4 weeks showed a significant inhibition of platelet aggregation in PRP when a submaximal ADP concentrations was administered.

Adenosine Diphosphate↗
PubMed1993

A hepatitis B virus pre-S-retinoic acid receptor beta chimera transforms erythrocytic progenitor cells in vitro.

In this report, we investigated the transforming properties of retinoic acid receptor beta (RAR beta). The v-erbA protein, which is the viral oncogenic homologue of the thyroid hormone receptor, was replaced by either the complete RAR beta (beta R) or a hepatitis B virus pre-S-RAR beta (H beta R) hybrid product in an avian erythroblastosis virus-based vector. In chicken hematopoietic cells, the H beta R protein was able to transform erythroid progenitor cells, whereas no such transformation was observed with the wild-type beta R protein. Moreover, the fully transformed phenotype was observed even in the absence of v-erbB, and H beta R-transformed erythroid cells grew independently of growth factors and transforming growth factor alpha. The analysis of erythrocytic-specific proteins revealed that the transformed cells were blocked at the colony-forming unit-erythroid stage and that the expression of the carbonic anhydrase II gene, a gene normally regulated by thyroid hormones, was repressed by the H beta R protein. Finally, hepatocarcinomas rapidly developed in some chickens infected in ovo with viruses encoding either the normal or the hybrid H beta R, suggesting that an inappropriate expression of the RAR beta gene may represent an important event in oncogenesis.

Amino Acid Sequence↗
PubMed1993

Transforming growth factor-beta 1 stimulates macrophage urokinase expression and release of matrix-bound basic fibroblast growth factor.

Macrophage expression of urokinase-type plasminogen activator (uPA) appears to play a role in their release of matrix-bound basic fibroblast growth factor (bFGF) and transforming growth factor-beta (TGF-beta). In experiments reported here, we have examined the potential regulatory effects of bFGF and TGF-beta 1 on macrophage uPA expression. TGF-beta 1 stimulated in a dose- and time-dependent manner the expression of secreted membrane and intracellular uPA activities by a macrophage cell line (RAW264.7). When examined at similar concentrations, bFGF had little effect, and interleukin-1 alpha, tumor necrosis factor-alpha, and monocyte colony stimulating factor had no effect on macrophage uPA expression. Exposure of macrophages to TGF-beta 1 led to a rapid and sustained increase in the steady-state levels of uPA mRNA that was independent of de novo protein synthesis and was completely inhibited by actinomycin D. However, the TGF-beta 1-induced increase in uPA mRNA was largely unaffected by subsequent incubation of cells with actinomycin D. The protein kinase C inhibitor H7 markedly reduced the ability of TGF-beta 1 to stimulate expression of uPA activity. Likewise, okadaic acid and microcystin, inhibitors of serine/threonine phosphatases, potentiated the ability of TGF-beta 1 to upregulate macrophage uPA expression. TGF-beta 1 primed cells converted nearly all added plasminogen to plasmin and expressed sixfold more membrane-bound plasmin than control cells. Preincubation of TGF-beta 1 with either serum or methylamine-modified alpha 2-macroglobulin did not affect its ability to induce macrophage uPA expression. When control and TGF-beta 1-primed macrophages were cultured on matrices containing bound 125I-bFGF, their release of 125I-bFGF was increased five and tenfold, respectively, in the presence of plasminogen. The ability of TGF-beta to induce macrophage uPA expression and the plasmin-dependent release of matrix-bound bFGF may provide an indirect mechanism by which TGF-beta stimulates angiogenesis.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1993

Forskolin blocks the apical expression of dipeptidyl peptidase IV in Caco-2 cells and induces its retention in lamp-1-containing vesicles.

In a previous work, we showed that the differentiation-dependent expression of dipeptidyl peptidase IV (DPP IV) in Caco-2 cells, a human colon adenocarcinoma cell line, was controlled at the mRNA level (D. Darmoul et al. J. Biol. Chem., 1992, 267, 4824-4833). Whether post-translational events may contribute to the final control of DPP IV cell surface expression was explored here by studying the potential effect of forskolin (FK), a drug known to permanently stimulates adenylyl cyclase and to strongly perturbs glucose metabolism in fully differentiated Caco-2 cells. FK treatment reduces by about 50% the amount of active DPP IV present at the brush border membrane, whereas the total amount of active DPP IV remains unchanged. Biosynthesis and maturation of DPP IV were measured using [35S]methionine labeling and were shown to be essentially unaffected by FK treatment. Pulse-chase experiments demonstrate that up to 50% of the neosynthesized DPP IV do not appear at the apical membrane after FK treatment. To get further insight into this phenomenon, we have used confocal laser scanning microscopy. We demonstrate that the blockade of DPP IV transport is associated with the accumulation of this protein in intracellular vesicles. Double-staining experiments demonstrate that these vesicles are not labeled with a monoclonal antibody directed against the Golgi apparatus but display a strong staining with a polyclonal antibody raised against lamp-1, a lysosomal membrane protein. Using a newly developed image analysis procedure, we have been able to quantitate the relative distribution of lamp-1 and DPP IV labels in both control and forskolin-treated cells. We show that the overlap of the two labels dramatically increases in FK-treated Caco-2 cells. These results suggest that, beside the transcriptional level, post-translational events may be involved in the final control of the apical expression of a differentiation-dependent hydrolase.

Antigens, CD↗
PubMed1993

Protective effect of under-reinforcement of passive avoidance against scopolamine-induced amnesia.

Administration of antimuscarinic drugs induces amnesia of aversively motivated behaviors. However, when relatively high intensities of footshock are used during training (over-reinforcement), animals become protected against such amnesic state. Moreover, the protective effect is established in a none-or-all fashion, i.e., within a series of increasing intensities a minute augmentation of footshock intensity is sufficient to reach the protective threshold. In the present experiment it was found that very low intensities of aversive stimulation (under-reinforcement), sufficient to produce learning, also protected animals from scopolamine-induced amnesia. These results suggest that acetylcholine is critically involved in memory consolidation of passive avoidance, but only within a limited range of training intensities.

Amnesia↗
PubMed1993

Intestinal microsporidiosis in a Chilean patient with acquired immunodeficiency syndrome (AIDS).

A 24-year-old male patient with AIDS diagnosed in 1989, and with several episodes of pneumocystosis, was admitted because of a chronic diarrheic syndrome and severe epigastric pain. Endoscopy showed a granular duodenal mucosa. Light microscopy showed a moderate villous atrophy with round-cell inflammatory infiltration of the chorion. Giemsa, Ziehl-Neelsen, and Gram stains showed microsporidial spores measuring between 1.5 and 2 microns in the supranuclear cytoplasm of some enterocytes. Electron microscopy showed sporoblasts and spores consistent with Enterocytozoon bieneusi, with an apparently non-tubular, rather electron-dense polar filament showing up to 7 coils and also a microtubular internal structure with annular disposition, a finding which has not been adequately emphasized in the pertinent literature, probably representing a contractile property of the polar filament, rather than a mere duct for the parasitic sporoplasm to be inoculated.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Osteochondritis dissecans: a historical review and its treatment with cannulated screws.

The etiology of osteochondritis dissecans and the results of treating the early stages with arthroscopic fixation using cannulated screws is discussed. Arthroscopic surgery was performed on 14 patients with osteochondritis dissecans, and the osteochondral fragment was fixed with one or two screws. A second arthroscopic procedure was necessary to assess the lesion and remove the screws. Ambulation without weight bearing is allowed during the first 2 months postoperatively. Full range of motion is encouraged. The results indicate that all patients returned to their previous sport 3-11 months postsurgery. The authors conclude that fixation with cannulated screws is the ideal method of treating osteochondritis dissecans when the osteochondral fragment is still in its bed.

Adolescent↗