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Biomedical subjects

M C Rodríguez

Publications and source records attributed to M C Rodríguez.

At least 19 recordsLinked to original sources
PubMed1997

[Carboxyhemoglobin levels in relation with home heating].

To study carboxyhemoglobin levels (HbCO) associated with use of different types of home heating and to evaluate the usefulness of measuring hemoglobin oxygen saturation. Nonsmoking patients with chronic respiratory insufficiency who were initially prescribed home oxygen therapy were enrolled in the study. One hundred four patients were studied in winter and summer (when heating was not used). The control group consisted of 92 hospitalized patients not exposed to carbon monoxide. Of the 104 patients 74.1% were men. Mean age was 72.33 (range 17 to 97 years) and 57.9% lived in rural areas. Mean HbCO in the control group was 1.53 +/- 0.96% (p = 0.01). Among the 39% who burned slack coal for heat, the mean HbCO was 4.63 +/- 2.87%. The 23.7% with central heating had HbCO levels of 2.15 +/- 0.87% (p < 0.0001). Pulse oximetry (SpO2) estimated higher hemoglobin oxygen than direct measurement (SaO2): 87.12 +/- 6% and 83.3 +/- 8%, respectively (p < 0.001). High HbCO concentrations are related to chronic exposure to slack coal fumes. Pulse oximetry, as opposed to SaO2, overestimates hemoglobin oxygen saturation in such cases.

Adolescent↗
PubMed1997

Surgical treatment of Parkinson's disease.

At present, there are three major surgical approaches to Parkinson's disease (PD): (1) Ablative surgery (i.e. pallidotomy, thalamotomy); (2) deep brain stimulation (DBS) of the thalamus, internal globus pallidus (GPi) and subthalamic nucleus (STN); and (3) grafting fetal mesencephalic cells into the striatum. As a result of increasing understanding of the pathophysiology of the basal ganglia and the demonstration of surgical alleviation of experimental parkinsonism, surgery has regained a paramount importance in the management of PD. The aim of pallidotomy and DBS is to reduce the excessive inhibitory output from the GPi and substantia nigra reticulata (SNr). Pallidotomy and DBS of the STN or GPi aim to reverse the pathophysiological consequences of dopamine deficiency in PD, and should be considered entirely symptomatic treatments. The ideal candidates for pallidotomy are young patients in good general health in whom dyskinesias are the main reasons for disability. Patients with severe bilateral problems uncontrollable with present pharmacological tools are candidates for DBS. As yet, there are no formal data to help decide how to choose between GPi and STN stimulation. In our practice, patients are allocated to GPi stimulation when 'on' dyskinesias are extremely severe. In most other instances, we prefer to perform STN stimulation. At present there is almost no reason to decide for the thalamic stimulation since tremor is equally arrested by STN stimulation, which in addition improves all other features of PD. Equally the only indication for thalamotomy would be a patient with long-standing tremor as the main clinical manifestation, which can not be controlled with drugs. The proportion of patients in whom the thalamus will be the preferable target for either DBS or thalamotomy is small (less than 5%). Grafting aims to repair the nigrostriatal pathway and restore dopaminergic function in the striatum. In the future implants containing not only dopaminergic cells but also growth factors and a variety of other substances could become a method to not only functionally compensate the biochemical abnormalities of PD but also to arrest its progression. This technique is limited to a few centres around the world owing to the technical, logistical and ethical problems of obtaining and handling embryonic cells. At present, grafting of dopaminergic cells is perhaps best suited for patients with young-onset PD (less than 45 years old) who are at high risk of developing complications within a short time of beginning pharmacological treatment and in whom the idea of making lesions or implanting electrodes into the brain for decades seems less appealing. Consideration of surgery in any given patient should be weighed against the risks (about 1% mortality and 2-6% of severe morbidity-hemiplegia, cognitive deficit, speech problems, etc.) associated with these techniques. The development of better imaging methods and the growing expertise of multidisciplinary teams will undoubtedly make surgery for PD safer and more effective in the future.

Electric Stimulation Therapy↗
PubMed1997

[Stereotactic surgery in Parkinson's disease].

Stereotactic surgery for Parkinson's disease (PD) has regained interest due to the recently described hyperactivity of the subthalamic-pallidal pathway. Many patients suffering from complications associated with the chronic use of levodopa may benefit from surgical treatments. There are different surgical targets and techniques (ablative and deep brain stimulation). The choice of one particular target and technique relies on the clinical symptoms of the patient. The risk/benefit ratio of surgery is related to the careful selection of patients and the technical accuracy. Intraoperative microrecording is considered the best method to avoid side effects and partial results. A series of patient's selection and follow-up assessment criteria are proposed.

Follow-Up Studies↗
PubMed1996

Effect of degree of unsaturation in dietary fatty acids on arachidonic acid mobilization by peritoneal macrophages.

Cells from rats fed with a tripalmitin diet showed a depletion of phospholipid arachidonate and n-3 fatty acids such as eicosapentaenoic and docosahexaenoic acids (EPA and DHA). In rats fed fish oil diet, a significant reduction in arachidonic acid (AA) content was observed whereas EPA and DHA were incorporated into membranes lipids. These changes in lipid composition of membranes did not affect cellular adherence, phagocytic capability, or [3H]AA incorporation. However, both tripalmitin and fish oil diets induced a decrease in [3H]AA mobilization stimulated by 4 beta-phorbol-12-myristate 13-acetate, A23187, or opsonized-zymosan in rat peritoneal macrophages. These results demonstrate that the antiinflammatory effects of essential fatty acids deficiency or n-3 enrichment diets may be associated with a decreased AA mobilization in resident rat peritoneal macrophages treated with proinflammatory agents.

Animals↗
PubMed1995

Inhibition of prostaglandin E2-responsive adenylyl cyclase in embryonal human kidney 293 cells by phorbol esters.

A clonal primary embryonal human kidney cell line, 293, increased cAMP production in response to prostaglandin E2 (PGE2) (0.02-2 microM). The purpose of this study was to show the effects of tumor-promoting phorbol esters (e.g., 4 beta-phorbol 12-myristate 13-acetate, PMA) on PGE2-stimulated cAMP production. Pretreatment with PMA (0.2-200 nM) for 30 min markedly reduced PGE2-stimulated cAMP production in the presence of 0.5 mM isobutylmethylxanthine. The reduction by PMA was dose- and time-dependent. PMA seems to attenuate the increase in cAMP accumulation elicited by PGE2 primarily, if not entirely, by inhibiting adenylyl cyclase activity, since we were unable to demonstrate an effect of PMA on the degradation half-life of cAMP in intact 293 cells. The action of PMA had some specificity for the agonist used; thus, PMA inhibited PGE2-activated adenylyl cyclase but had no effect on the forskolin-activated enzyme. Co-pretreatment with PMA and H-7, an inhibitor of protein kinase C (PKC), partially prevented the PMA-induced attenuation of the PGE2-stimulated cAMP accumulation, and 1-oleoyl-2-acetylglycerol, a synthetic diacylglycerol analog, partially mimicked the PMA action. Thus, PMA appeared to decrease cAMP production by a PKC-mediated mechanism, inhibiting adenylyl cyclase activity at a point other than the catalytic subunit of the enzyme in the kidney 293 cell line.

Adenylyl Cyclase Inhibitors↗
PubMed1995

Dietary lipid and iron status modulate lipid peroxidation in rats with induced adjuvant arthritis.

We studied the effect of dietary lipids on iron metabolism and lipid peroxidation during induced adjuvant arthritis and/or iron overload in rats. We compared a control diet containing corn oil and rapeseed oil with a diet devoid of polyunsaturated fatty acids containing only tripalmitin as lipids. Four subgroups of rats were used with each diet: without further treatment, with induction of adjuvant arthritis, with iron overload, and with induction of adjuvant arthritis and iron overload. The profile of fatty acids present in plasma and in microsomes changed in rats fed the tripalmitin diet. The level of tetra- and pentaunsaturated fatty acids was reduced, and the level of monounsaturated fatty acids and iron stores was increased with respect to control rats. Thus, ingestion of a tripalmitin diet reduced the substrate for lipid peroxidation, as shown by the decrease in thiobarbituric acid-reactive substances in plasma and conjugated dienes in hepatic microsomal fraction. Adjuvant arthritis and iron overload had a synergistic effect on lipid peroxidation and iron storage in liver. Further, in the hepatic microsomal fraction, tripalmitin reduced the levels of cytochrome P-450, and arthritis reduced the levels of cytochrome P-450 and Ca2+ sequestration. Our results suggest that rats fed tripalmitin showed a reduction of lipid peroxidation induced by inflammation or by iron overload, because of the lack of polyunsaturated fatty acids in the diet, although tripalmitin usually increases the iron stores in the body and causes hepatic alterations.

Animals↗
PubMed1995

[Development of a computer program to assess nutritional status of infants and preschool children].

A computer program named INFANDIET has been designed with a Window's application (ToolBook software vs. 1.53), based upon object-oriented programming, and devised to assess the nutritional status of infants by using compatible computers PC. Additionally, it is a useful tool to elaborate personalized diets. This program has been developed to assist health professionals and students in the evaluation of the infant nutritional status by a) creating and managing clinical histories with anthropometrical, immunological and clinical data; b) showing infant dietary guidelines, with the ability to update the nutritional and food composition database of the program; c) giving information about infant nutrition; d) and presenting a complete list of references.

Child, Preschool↗
PubMed1993

X-linked agammaglobulinemia and gastric adenocarcinoma.

BACKGROUND: The incidence and mortality rate for cancer in patients with primary immunodeficiency diseases have increased greatly. Lymphomas constitute more than 50% of tumors identified in the Immunodeficiency Cancer Registry, but solid tumors are frequent in these patients, especially gastric carcinomas. In addition to immunologic impairment, other local conditions such as chronic atrophic gastritis with intestinal metaplasia and pernicious anemia, usually observed in these patients, may play an important role in the genesis of gastrointestinal tumors. METHODS AND RESULTS: This report describes a 23-year-old patient with X-linked agammaglobulinemia who had previously documented chronic atrophic gastritis with intestinal metaplasia, pernicious anemia, and parasitization with Giardia lamblia in whom an adenocarcinoma of the stomach developed. CONCLUSION: The authors believe that it may be useful to perform a periodic gastrointestinal evaluation for all patients with primary immunodeficiencies to establish early detection and treatment of these tumors.

Adenocarcinoma↗
PubMed1993

[A computer program for assessing nutritional status and diet preparation].

This computer program has been written in a BASIC language and designed to assess the nutritional status by means of anthropometrical, immunological and clinical data. Additionally, it is useful for the design and elaboration of personalized diets. The use of this program will allow to work with a great amount of nutritional information, besides, it will outstandingly reduce work time and increase accuracy to diagnose specific nutritional problems. The data base of this program has been made on the basis of current nutritional information and it can be easily updated when necessary.

Algorithms↗
PubMed1992

Truncation of the cytoplasmic tail of the lutropin/choriogonadotropin receptor prevents agonist-induced uncoupling.

An agonist-induced change in the functional properties of a constant number of receptors seems to be a ubiquitous phenomenon involved in the regulation of cell surface receptors. Although the mechanisms responsible for this phenomenon (called uncoupling or desensitization) have been studied in detail using beta 2-adrenergic receptors it is unclear if the models derived from these studies are applicable to other members of the family of G protein-coupled receptors. Since it has been shown previously that truncation of the C-terminal cytoplasmic tail of the beta 2-adrenergic receptor results in a delay in the onset of agonist-induced uncoupling (Bouvier, M., Hausdorff, W.P., De Blasi, A., O'Dowd, B.F., Kobilka, B.K., Caron , M.G., and Lefkowitz, R.J. (1988) Nature 333, 370-373), we now present experiments designed to test the effects of a similar truncation of the lutropin/choriogonadotropin (LH/CG) receptor on its functional properties. The results presented herein show that (i) clonal lines of human embryonic kidney cells stably transfected with cDNAs encoding for the wild-type (rLHR-wt) or a mutant receptor truncated at amino acid residue 631 (rLHR-t631) express functional LH/CG receptors as judged by their ability to bind hCG and to respond to it with increased cAMP accumulation; (ii) a preincubation of the cells expressing rLHR-wt with hCG leads to a reduction in the ability of hCG to activate adenylylcyclase; and (iii) this reduction is severely blunted in cells expressing rLHR-t631. These results demonstrate that the C-terminal cytoplasmic tail of the LH/CG receptor is necessary for agonist-induced uncoupling.

Animals↗
PubMed1992

[An analysis of the obligatory reporting of meningitis in a pediatric area].

AIMS: To find out the validity, reliability and quality of the epidemiological information which comes from the System of Statutory Declarations. The example used is the incidence of Meningitis. DESIGN: Descriptive study of the coverage of the Declaration, with the help of the EDO (Illnesses requiring a Statutory Declaration) index, of the pediatric (up to 14 years old) cases of meningitis attended in our Area between 1984 and 1989. We analysed how the Declaration had been filled in and the agreement between the information gathered through the notification system and clinical records. SITE. The whole network of epidemiological vigilance: hospitals, provincial epidemiological services and primary care services. PATIENTS: All the cases of child meningitis (120 cases) seen in the Mother and Child Hospital in our area between 1984 and 1989. MAIN MEASUREMENTS AND RESULTS: The meningitis declaration covered 47.5% of the total number of cases seen. In the cases declared, the diagnosis of meningococcal meningitis on the EDO index was 89.5%, whereas the rate in the clinical reports was only 20%. Thus agreement in the diagnosis does not exceed what could be produced by chance (Kappa = 2.5%; p = NS), as agreement for all diagnoses is 7.1%. CONCLUSIONS: Our results demonstrate a low level of declaration, poor standard of compliance and scant agreement between the Statement of Declaration and the clinical report. The validity and reliability of this information is extremely low and suggests a need to re-consider the usefulness of this vigilance system for health-service practice, especially in Primary Health Care.

Adolescent↗
PubMed1992

Changing glycine 21 for glutamic acid in the beta-subunit of penicillin G acylase from Kluyvera citrophila prevents protein maturation.

Active penicillin acylase from Kluyvera citrophila strain ATCC 21,285 consists of two different alpha- and beta-subunits derived from a single precursor by post-translational processing. Using the chemical mutagen hydroxylamine we have treated plasmid pYKD59 containing the active penicillin acylase gene (pga) from K. citrophila and have generated different point mutant penicillin acylase genes, one producing a maturation deficient precursor. This point mutation has changed the glycine 310 residue of the precursor for a glutamic acid (residue number 21 of the mature beta-subunit). The introduction of a charged residue in this position did not prevent translocation of the precursor to the periplasm but the resultant molecule was not able to undergo subsequent post-translational modification to yield the active protein.

Amino Acid Sequence↗
PubMed1991

[Immunologic changes in sickle-cell anemia].

In order to assess the status of their immunologic system, a study was carried out in 38 adults with sickle-cell anaemia. Fifty healthy blood donors were used as control group. Significant decrease of serum albumin (p less than 0.02) and increase of alpha-globulins (p less than 0.01) and gamma-globulins (p less than 0.001) were present in the patients. They showed also significantly decreased percentage of spontaneous rosette-forming lymphocytes (p less than 0.01) and of lymphocytes responding to anti-CD3 monoclonal antibody (p less than 0.05) with respect to the control group. Such relative T-cell decrease in peripheral blood seemingly took place by means of decreasing CD4-positive subpopulations, whose percentage was significantly lower (p less than 0.001) in the patients than in the control subjects. Functional studies showed a significant decrease (p less than 0.001) of the activity of natural cytotoxic cells. None of the patients had antibodies against human immunodeficiency viruses type 1 and type 2, and 60% of them were positive to cytomegalovirus test. No statistical correlation was found between the immunological findings and the presence of antibodies against such virus, neither such alterations correlated with the number of blood units received by the patients.

Adolescent↗
PubMed1991

[Primary segmental sclerosing cholangitis associated with Sjögren's syndrome].

We report the case of a patient with primary sclerosing cholangitis associated with Sjögren's syndrome and Raynaud's phenomenon, an uncommon association. The presence of periportal lymph nodes with features similar to those described in autoimmune diseases suggests an immune pathogenesis of the disease. The localized and segmentary involvement of the common duct is also an uncommon finding. The pathogenetic and therapeutic aspects are discussed.

Aged↗
PubMed1991

Age structure and abundance levels in the entomological evaluation of an insecticide used in the control of Anopheles albimanus in southern Mexico.

Applications of bendiocarb produced a high insecticidal residual effect lasting up to 3 months on the most common indoor house surfaces. No significant decreases in mosquito man-biting rate levels were observed between treated and untreated villages. It was shown that almost equal proportions of intra- and peridomicillary mosquitoes came into contact with the insecticide, indicating that mosquitoes commonly enter houses, rest on treated surfaces and return to bite both indoors and outdoors. Although the insecticide was found to have a significant effect on the percentage parity (interpreted as abundance of older individuals) of intra- and peridomicillary Anopheles albimanus mosquitoes, parity recovered and continued a normal cyclic pattern that appeared to be dependent on relative abundance. The proximity of a treated village to an untreated village (1.2 km) can affect the age structure of mosquito populations through shared common resting and breeding sites.

Age Factors↗
PubMed1989

Annual changes in the number, testosterone content and ultrastructure of glandular tissue cells of the testis in the marbled newt Triturus marmoratus.

The testes of 8 specimens of Triturus marmoratus were collected during each month of 1987 and processed for electron microscopy and light microscopy demonstration of testosterone (T) following the ABC (avidin-biotin peroxidase complex) method. According to their staining affinity for anti-T antibodies, the glandular tissue cells were classified as T-, T+, T++, and T and the annual changes in the numbers of these cell populations, as well as in the volume occupied by the glandular tissue, were calculated. The volume occupied by the glandular tissue increases from September to December; it begins to decrease in April and disappears from June to August. The glandular tissue is formed from the interstitial cells that surround the lobules containing differentiating germ cells. During the spermatogenic process, the interstitial cells do not show staining affinity for anti-T antibodies. In August-September, the interstitial cells around the lobules that have completed spermatogenesis become positively stained (T+) and form the glandular tissue when the spermatozoa leave the testis. The numbers of intensely stained cells in the glandular tissue (T++ and T ) increase from September to November; begin to decrease in December; disappear in January-February; increase again in March and decrease again in April until they disappear in June-September. The interstitial cells, before their transformation in glandular tissue, are ultrastructurally similar to fibroblasts. After their transformation these cells increase in size and develop abundant smooth endoplasmic reticulum, mitochondria with tubular cristae and lipid droplets. This morphological pattern is maintained in the glandular tissue from September to April in spite of the changes in staining affinity during this period.

Animals↗