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Biomedical subjects

A Navarro

Publications and source records attributed to A Navarro.

At least 109 records · Page 6Linked to original sources
PubMed1998

The Girdlestone pseudarthrosis in the treatment of infected hip replacements.

The results of 78 resections of the head and neck of the femur (Girdlestone pseudarthrosis) in patients with infected hip replacements were studied. The mean follow-up was 5 years. At the time of the resection, gram-positive organisms were found in 53% of the cases, gram-negative in 33%, and in 12% there were mixed flora. The Girdlestone pseudarthrosis controlled the infection in 86% and achieved satisfactory relief of pain in 83%. The mean shortening of the limb was 4.1 cm and every patient needed some type of external walking aid. We found no correlation between the type of organisms and the persistence of infection, nor between shortening and the functional results. The Girdlestone pseudarthrosis is an acceptable method of controlling infection and relieving pain after infection of a total hip replacement.

Adult↗
PubMed1998

Alcohol, methylxanthine-containing beverages, and colorectal cancer in Córdoba, Argentina.

The relationship between social class indicators, body mass index (BMI), selected life-style habits (alcohol, coffee, maté and tea drinking) and colorectal cancer was investigated in a case-control study conducted between 1993 and 1997 in Córdoba, Argentina, a relatively high mortality area of colorectal cancer. Cases were 190 patients below age 80 years with incident, histologically confirmed colorectal adenocarcinomas, and controls were 393 patients admitted to hospital for a wide spectrum of acute, non-neoplastic disorders. Higher social class, based on occupation of the head of the household, was significantly associated with colorectal cancer risk: the odds ratios (OR) and 95% confidence intervals (95% CI) were 1.9 (1.2-2.9) for intermediate and 2.0 (1.2-3.4) for the highest as compared to the lowest social class individuals. When compared with subjects whose BMI was < 25 kg/m2, the OR was 1.1 (0.7-1.6) for those with BMI 25 to 29 kg/m2, and 1.3 (0.7-2.3) for those > or = 30. In comparison with alcohol abstainers, the OR was 2.8 (1.6-5.1) for drinkers, and there was a significant trend in risk with dose. The association was observed with wine (the most common alcoholic beverage in Argentina), as well as for beer and spirits. The consumption of coffee, maté and tea was not significantly related to colorectal cancer, but the ORs were below unity (0.9 (0.7-1.3) for coffee, 0.9 (0.6-1.2) for maté and 0.8 (0.6-1.2) for tea drinkers). The relationship between social class, alcohol drinking and colorectal cancer were consistent across strata of sex and age. This study confirms that colorectal cancer has positive social class correlates. The association with alcohol drinking is apparently stronger than previously reported, and may be due to the role of chance and/or peculiar correlates of alcohol drinking in this Argentinean population.

Adult↗
PubMed1998

Trapezius transfer for shoulder paralysis. 6 patients with brachial plexus injuries followed for 1 year.

We transferred the trapezius with its bone insertion to the proximal humerus in 6 patients for treatment of a paralytic shoulder secondary to traumatic lesions of the brachial plexus. After 1 year, the shoulder abduction was improved from average 13 degrees (0 degrees-30 degrees) preoperatively to 76 degrees (50 degrees-100 degrees) postoperatively, and the shoulder flexion from 18 degrees (0 degrees-40 degrees) to 78 degrees (45 degrees-110 degrees) postoperatively. All the patients were satisfied with the outcome. We consider that transfer of the trapezius in a paralytic shoulder after brachial plexus injury gives a better outcome than shoulder fusion.

Adult↗
PubMed1998

[The incidence of Culicidae in an urban area of Ciudad de La Habana during 1995].

In the present paper it is made an analysis of the incidence of culicides in the municipality of Marianao, Havana City, during 1995, after following the requirements of the National Program for the Eradication of Aedes aegypti. 6 species of mosquitoes were found in the municipality, with a predominance of the Culex quinquefasciatus and Aedes mediovittatus species. 4 focuses of Aedes aegypti were detected during this period. It was found that the groups of deposits preferred by the culicides for their breeding in this municipality were other deposits, low tanks, artificial deposits and larva traps. The People's Councils 4 and 5 (Libertad and Pogolotti) had the highest number of focuses (967 and 1,240, respectively, and therefore, they need more attention. It is analyzed the influence of the deficiencies of the public services, such as the collection of solid, wastes (garbage) and the existence of leakages and sewing overflows, on the proliferation of mosquitoes in the municipality.

Animals↗
PubMed1998

[The effect of 2 diets on the biological aspects of Blattella germanica (Dictyoptera: Blattellidae) under laboratory conditions].

It was conducted a study of 2 colonies of Blattella germanica (Dictyoptera: Blattellidae) kept since 1994 in the laboratory at 29 +/- 1 degrees C, 70-75% of relative humidity and with different foods: one on a diet without proteins, consisting in portions of potatoes (Solanum tuberosum, L.), ripe banana (Musa paradisiaca, L.) and a sugary solution 10%, and the other with a protein content of 20.45% composed of pulverized and dry laboratory food for rats and a source of water. 6 nymphal stages were found with both types of food. There were determined the times of interchanges and the time of nymphal development, which were much shorter among the nymphs fed with proteins. The longevity of each sex showed no significant differences in connection with the type of food used. The times of appearance and eclosion of the oothecae of each oothecal cycle were determined with both foods. It was found that the females deposited up to 5 oothecae during their lives with the 2 types of diet. The average of nymphs per ootheca among the females fed with proteins was much greater (t = 5.33; p < 0.001). The results of this study show that when the food for B. germanica contains proteins, its nymphal development is faster and its reproductive capacity increases, which means that protein is a necessary nutrient for the diet of this species.

Analysis of Variance↗
PubMed1998

[Patient with Hansen disease and lepromatous reaction with predominant neural involvement].

We describe a patient with a diagnosis of Hansen's disease borderline type, presenting as cutaneous lesions and silent multineuritis. Samples of nasal mucus, earlobe and cutaneous lesions were positive for acid-fast bacilli. He was given treatment with rifampin, dapsone and clofazimine. Five years later, he developed fever, poliarthritis, orchitis and hepatic involvement. Searching for acid-fast bacilli in many cutaneous and mucosal locations was fruitfulness. Because of clinical suspicion of erythema nodosum leprosum, he was treated with steroids with improvement of his clinical picture, but subsequently he developed multineuritis with many sensitive symptoms. A high number of bacilli was seen in nerve biopsy. We comment on atypical features of clinical evolution and erythema nodosum leprosum, and emphasize the significance of large number of bacilli into peripheral nerve in contrast with their absence at other levels.

Biopsy↗
PubMed1998

[The effects of aging on the volume of human vestibular nuclei].

Elderly persons often have balance disorders, with dizziness that sometimes leads to falls. Changes in the peripheral vestibular system with age, with loss of the hair cells and neurons of Scarpa's nucleus, have been studied for years. However, the changes in the vestibular nuclear complex with age have not been examined. We studied paraffin-embedded brainstems from nine persons of different ages in order to analyze possible changes with age. No abnormalities were observed in the volume or length of the vestibular nuclei, except for a decrease in both dimensions in the superior vestibular nucleus (SNV). All the main vestibular nuclei showed an increase in lipofuscin content with age that seemed to be less marked in the SNV. The low lipofuscin concentration in the SNV could be related with the conservation of vestibular reflexes, the center of which seems to be the SVN, in elderly persons.

Adult↗
PubMed1998

Coccidioides immitis presenting as a hyphal form in cerebrospinal fluid.

This article reports a case of Coccidioides immitis that presented as a hyphal form in a 38-year-old patient. The organism was observed growing exclusively as hyphae in the cerebrospinal fluid by microscopic examination. Coccidioides immitis was the only organism cultured. The identification of C immitis was confirmed by both standard culture methods and DNA probe studies.

Adult↗
PubMed1997

Morphometric analysis of the human vestibular nuclei.

BACKGROUND: Cytoarchitectural investigations of the vestibular nuclei have been undertaken in different species of mammals. These data provide a description of the general architecture of the nuclei but limited information about quantitative characteristics of their cell population. We have recently obtained data about the morphometric parameters of the vestibular nuclei neurons in some species. The application of quantitative image analysis techniques to the research of the cellular morphology in the vestibular area of humans might provide basic information to compare with data from animal studies, taking into account the observed correlation between physiological and morphological properties of vestibular neurons. METHODS: The characteristics of the major vestibular nuclei in humans have been studied with light microscopic techniques in serially cut sections. Camera lucida drawings of the vestibular nuclei and their neurons were made and subjected to computerized image analysis. For each vestibular nucleus, information was obtained about topography, morphological characteristics (i.e., location, volume, and length), and the number and morphometric parameters of their neurons (cross-sectional areas, maximum and minimum diameters). Morphometric data about cell parameters were statistically analyzed by comparing the populations within different parts of each nucleus and from different nuclei. RESULTS: Among the vestibular nuclei, the medial, which is the largest, has the greatest number of neurons, and the interstitial, the least. The lateral and interstitial nuclei contain the largest cells, and the descending nucleus has the smallest cells. The superior nucleus contains cells of intermediate size. The size of cells decreases in a rostrocaudal direction in the medial, lateral, and descending nuclei, the opposite trend being observed in the superior nucleus. Within the superior and medial nuclei, there are discrete areas with cells with distinctive characteristics. CONCLUSIONS: These results suggest that, just as most of the anatomical characteristics of the second-order neurons found in animals have been preserved in humans, so the physiological mechanisms observed in the vestibular system of animals should apply to humans.

Adult↗
PubMed1997

The magnocellular neurosecretory system of the hamster hypothalamus: an ultrastructural and morphometric study during lifetime.

A quantitative study regarding the age-related changes occurring in the nucleus and the somatic organelles of neurosecretory magnocellular neurons of the hypothalamo neurohypophyseal system (HNS) was carried out in the hamster at six age-points during animal life. The magnocellular cells of both parts of the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) of male Syrian hamsters between 3 and 30 months of age were examined ultrastructurally. Cells of all age groups present the same morphological ultrastructure. Standard manual morphometric techniques are used to calculate the following parameters related directly or indirectly with cellular activity: nuclear area, nucleolar area, nuclear invagination index and volumetric fractions of some intracellular structures (Golgi apparatus, mitochondria, rough endoplasmic reticulum and lipofuscin). With respect to the cell nucleus, the parameters are not modified during aging. No significant differences in the volume density of subcellular components, except lipofuscin, were detected at the age groups studies. However, there is a positive linear trend among all parameters and age except for the rough endoplasmic reticulum. Our results suggest maintenance of the synthetic activity of the magnocellular neurons in the hamster during aging but in no case an increase in their metabolic activity.

Aging↗
PubMed1997

Modulation of GH4 cell cycle via A1 adenosine receptors.

Identification and characterization of A1 adenosine receptors (A1Rs) in a tumor cell line derived from rat pituitary (GH4 cells) was performed by ligand binding and immunocytochemistry. Subsequently, the involvement of A1Rs in the regulation of cell proliferation was studied in these cells. The agonist N6-(R)-phenylisopropyladenosine (R-PIA) did not modify the number of cultured cells, but it regulated the kinetics of the cell cycle. By means of experiments of pulse and of pulse and chase with bromodeoxyuridine and further labeling with Hoechst 33258, propidium iodide, and/or fluorescein-conjugated antibodies against bromodeoxyuridine, it was demonstrated that R-PIA, via A1Rs, accelerated progression from G0/G1 to S phase and from S to G2/M phase of the cell cycle, whereas the initiation of a new cycle occurred at the same time in treated and untreated cells. As a consequence, R-PIA did not change the total length of the cycle. This is the first description of cell cycle regulation without modification of cell proliferation. Although pertussis toxin blocked the R-PIA-induced inhibition of cyclic AMP production in these cells, it did not affect the R-PIA action on the cell cycle. In contrast, cholera toxin mimicked the action of R-PIA. Thus, it is likely that regulation of the cell cycle via A1Rs is mediated by heterotrimeric G proteins different from those that mediate inhibition of adenylate cyclase. Due to the fact that cells in G0/G1 phase were less susceptible to secretory signals, adenosine, in an autocrine manner and by regulating the cell cycle kinetics, may contribute to the modulation of the secretory capacity of pituitary cells.

Adenosine↗
PubMed1997

Regulation of L-type calcium channels in GH4 cells via A1 adenosine receptors.

Identification of A1 adenosine receptors (A1Rs) in a tumor cell line derived from rat pituitary (GH4 cells) was performed by ligand binding and immunological experiments. Subsequently, the involvement of A1Rs in the regulation of calcium conductance was studied in these cells. The agonist N6-(R)-(2-phenylisopropyl)adenosine (R-PIA) did not modify the intracellular calcium basal levels, whereas it inhibited the increase produced by 15 mM KCl depolarization. The antagonist 1,3-dipropyl-8-cyclopentylxanthine led to the opening of voltage-dependent cell surface calcium channels in the absence of exogenous KCl. The channels were of the L type because the effect was abolished by calciseptine and by verapamil. These results suggest that endogenous adenosine exerts a tonic inhibitory effect on calcium transport. This was confirmed by the high adenosine concentration found in cell supernatants (up to 1 microM) and by the calcium mobilization produced by exogenously added adenosine deaminase. In depolarizing conditions, the calcium peak in the presence of adenosine deaminase was reduced when cells were preincubated with R-PIA, thus suggesting that A1R activation regulates the intensity of depolarization. These results demonstrate that adenosine is an important regulator of the physiological state of pituitary tumor cells by modulating, in an autocrine manner, the activity of L-type voltage-dependent calcium channels.

Adenosine↗
PubMed1997

The estimation of the number and the length distribution of gene conversion tracts from population DNA sequence data.

DNA sequence variation studies report the transfer of small segments of DNA among different sequences caused by gene conversion events. Here, we provide an algorithm to detect gene conversion tracts and a statistical model to estimate the number and the length distribution of conversion tracts for population DNA sequence data. Two length distributions are defined in the model: (1) that of the observed tract lengths and (2) that of the true tract lengths. If the latter follows a geometric distribution, the relationship between both distributions depends on two basic parameters: psi, which measures the probability of detecting a converted site, and phi, the parameter of the geometric distribution, from which the average true tract length, 1/(1-phi), can be estimated. Expressions are provided for estimating phi by the method of the moments and that of the maximum likelihood. The robustness of the model is examined by computer simulation. The present methods have been applied to the published rp49 sequences of Drosophila subobscura. Maximum likelihood estimate of phi for this data set is 0.9918, which represents an average conversion tract length of 122 bp. Only a small percentage of extant conversion events is detected.

Animals↗
PubMed1997

Recombination and gene flux caused by gene conversion and crossing over in inversion heterokaryotypes.

A theoretical analysis of the effects of inversions on recombination and gene flux between arrangements caused by gene conversion and crossing over was carried out. Two different mathematical models of recombination were used: the Poisson model (without interference) and the Counting model (with interference). The main results are as follows. (1) Recombination and gene flux are highly site-dependent both inside and outside the inverted regions. (2) Crossing over overwhelms gene conversion as a cause of gene flux in large inversions, while conversion becomes relatively significant in short inversions and in regions around the breakpoints. (3) Under the Counting model the recombination rate between two markers depends strongly on the position of the markers along the inverted segment. Two equally spaced markers in the central part of the inverted segment have less recombination than if they are in a more extreme position. (4) Inversions affect recombination rates in the univerted regions of the chromosome. Recombination increases in the distal segment and decreases in the proximal segment. These results provide an explanation for a number of observations reported in the literature. Because inversions are ubiquitous in the evolutionary history of many Drosophila species, the effects of inversions on recombination are expected to influence DNA variation patterns.

Animals↗
PubMed1997

[Secondary prevention of myocardial infarction in Spain. The PREVERSE study].

INTRODUCTION AND OBJECTIVES: We present the results from the PREVESE Study, conducted in two phases: the first to identify the secondary prevention measurements recommended in Spain in patients who were discharged after a myocardial infarction; the second, 6 months later, to determine their evolution. METHODS: Data was collected from 1,242 patients in 39 hospitals. An analysis was made of the patients background, risk factors, working status, diagnostic procedures used during hospitalization, laboratory findings and drug therapy prescribed at discharge. At the second control, the risk factors status, diagnostic or assessment tests performed during the 6-month period, working status, mortality and cardiac events were revised. RESULTS: The previous history and risk factors studied showed a high risk profile among patients after myocardial infarction. Among the drug therapies prescribed at discharge the small percentage (6.7%) of lipid lowering prescriptions should be highlighted. An improvement in the risk factor profile was found at the six month checkup with a substantial reduction in the number of smokers, a very low number of hypertensives and an improvement in physical activity. There was no improvement in total-cholesterol levels. CONCLUSIONS: The implementation of preventive measures is not similar in all risk factors. An improvement is reached in prevention of smoking habit and hypertension, but not in the treatment of abnormal levels of hyperlipidemia.

Humans↗
PubMed1997

[Composition of saturated and unsaturated fatty acids of foods frequently consumed in Argentina].

The composition of food lipid, including total lipids, saturated, monosaturated, and polyunsaturated fatty acids was analysed in this study. Foods, which were frequently consumed in Argentina and include in this study were: lean and fatty red meats, "ossobucco" with or without bone marrow, lean and skinned chicken meager and fatty fish, several sausages (salami and blood sausage), several crackers, hand-made fatty bread, fried and baked biscuits, ice cream, milk-marmelade, edible oils and bovine tallow. The content of fatty acids grouped according to their families in the food and description of the formulation of each food are given in the current paper. The glossary will help to identify the preparation of foods and will be beneficial for the people in other countries of Latinoamérica.

Argentina↗