Biomedical subjects
Publications and source records attributed to M García.
A cohort epidemiologic study of second primary tumours appeared in patients diagnosed of laryngeal neoplasms, between years 1988 and 1990, and a follow-up term of 5 years, is presented. An statistical analysis of several data to define a possible high risk group for developing primary tumours was performed for all patients.
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Despite improvements in tube design and materials, the longer survival rates of critically ill patients make laryngeal and tracheal lesions still common following prolonged translaryngeal intubation. The time of intubation is almost the only factor employed in deciding whether or not tracheotomy has to be performed. Some patients will not develop laryngeal lesions afer long intubation periods, whereas some already have clinical symptoms after short periods of time. If the conditions of the larynx and trachea could be assessed before irreversible complications take place, then timing of tracheotomy could be individualized to avoid laryngeal stenosis as well as unnecessary tracheostomies. We present the preliminary results of an endoscopic study of the early laryngeal changes that take place during translaryngeal intubation. The method of exploration is explained and tissue changes seen and their evolution after extubation are described, emphasizing those that could have a predictive value.
Normal ageing is associated with different changes in the cardiovascular system that lead to an increase in pathological processes such as hypertension and heart failure. Therefore the importance of glutathione peroxidase and catalase for protection against peroxidation was studied in the rat heart. Each of the these enzymes was regulated by feeding rats a low selenium diet either unsupplemented or supplemented with 0.4 parts per million of selenium, with or without the catalase inhibitor, sodium fluoride, in their drinking water. After 2 months, selenium deficient rats had 87% reductions in mitochondrial and cytosolic glutathione peroxidase activities. These reductions were accompanied by increased peroxidation in heart homogenates and mitochondrial suspensions. Since increased mitochondrial peroxidation only occurred when both the cytosolic and mitochondrial glutathione peroxidase activities were involved, these selenoenzymes appear to work in tandem and reductions in both are a prerequisite for increased peroxidation in the heart. Peroxidation did not occur in sodium fluoride treated rats even though cytosolic catalase activity was inhibited by 70%. Moreover, inhibition of catalase activity did not exacerbate the level of peroxidation in selenium deficient rats depleted of glutathione peroxidase activity. Because increased peroxidation was only associated with reductions in glutathione peroxidase activity irrespective of catalase activity, the selenoenzyme appears to be more important for detoxification of hydrogen peroxide in the heart.
BACKGROUND: The fish parasite Anisakis simplex is the etiologic agent of anisakiasis and induces IgE-mediated reactions. Skin prick tests (SPTs) and the measurement of specific IgE to A. simplex were, in our experience, not valid tools with which to discriminate between allergic and nonallergic patients because many control subjects also had positive results. OBJECTIVE: The study was carried out to assess the usefulness of IgE immunoblotting in the diagnosis of allergy to A. simplex. METHODS: We have studied 61 patients with acute symptoms of urticaria, angioedema, or anaphylaxis and positive specific IgE to A. simplex. According to the anamnesis, time interval between ingestion of fish and clinical onset of symptoms, and exclusion of other causes of allergy, three different groups of patients were established: group A (allergic), group NA (non-allergic), and group D (doubtful). Fifty-one healthy donors were included as control subjects (group C). IgE immunoblotting with A. simplex whole-body extract was performed in all patients and control subjects. RESULTS: Four patterns of immunoblotting were observed: type 1, with a group of several bands of medium molecular weight and others of low molecular weight; type 2, two or more bands of medium molecular weight; type 3, only one band of medium molecular weight; type 4, without any band. There was a significant predominance of blotting type 1 in group A and type 4 in group C. CONCLUSION: These data suggest that IgE immunoblotting is the most useful approach to A. simplex allergy diagnosis.
The phylogenetic relationships of the hemagglutinin (HA) and non-structural (NS) genes from avian influenza (AI) H5 subtype viruses of North American origin are presented. Analysis of the HA genes of several previously uncharacterized isolates from waterfowl and turkeys provided clear evidence of significant sequence variation and existence of multiple virus clades or sub-lineages, maintained in migratory waterfowl. Phylogenetic analysis of NS gene sequences further demonstrated multiple sub-lineages and also demonstrated re-assortment of two NS alleles in wild duck populations. Based on currently available HA1 gene sequences, at least four clades exist with waterfowl isolates included in three of the four groups. The most genetically unstable of these sub-lineages is composed of recent poultry isolates from the outbreak of AI in Central Mexico. This group of viruses, which replicated unabated in chickens for at least 16 months, exhibited an increased rate of mutation in both the HA and NS gene. Comparison of the HA1 sequence data for all available North American H5 subtype viruses demonstrated minimal variation both in and around the amino acids predicted to be involved in the HA receptor binding site. The sequences also revealed that migratory waterfowl, live poultry market chicken, and turkey isolates uniformly lack a glycosylation site at amino acid 236 in the HA protein which is present in commercial chicken isolates.
Recent highly pathogenic (HP) field isolates of avian influenza (AI) virus from Mexico all possess an insertion of at least two basic amino acids (arg-lys) at the cleavage site of the hemagglutinin (HA) glycoprotein. One HP isolate has additional information which yields a 4 amino acid insert (arg-lys-arg-lys). We present here the nucleotide sequence of the HA gene of this unique isolate and compare it to recent H5N2 and other avian influenza isolates. The complete HA nucleotide sequence of the isolate and phylogenetic relationship suggest that it was derived in direct succession from a non-pathogenic strain isolated about 1 month earlier. The unique insertion sequence is a direct duplication of part of the purine-rich region preceding the arginine codon at the HA cleavage site. This evidence along with other data in this report provide compelling support for a proposed model explaining the mechanism of spontaneous, virulence-related insertions in type A influenza viruses.
We have developed a computerized automatic X-ray image acquisition system. It consists of conventional pressure and flow transducers connected to a commercial data acquisition card installed in a PC/AT, the card output being connected through a relay to a conventional X-ray system. Signal processing, that has been applied for automatic detection of inspiration and expiration in respiratory signals, allows the X-ray equipment activation at a given moment of the respiratory cycle. Radiographs are thus obtained either in inspiration or expiration at tidal volume on anaestesized experimental animals. The system has also been tested on non-collaborating patients.
Laryngeal papillomatosis is one of the first diseases where interferon (IFN) was found to be effective. In 1983, a programme for the treatment of all such cases started in Cuba. Up to December 1991, 125 patients (92 children, 33 adults) have been treated: 102 with leucocyte IFN-alpha, 12 with recombinant IFN-alpha-2b, and 11 have received both preparations. Case management consisted of surgical removal of the lesions followed by an IFN schedule starting with 10(5) IU/kg of weight in children or 6 x 10(6) IU in adults, i.m. daily. The dose was progressively reduced, as long as no relapses occurred. At the end of the one-year schedule the doses were reduced to 5 x 10(4) IU/kg in children or 3 x 10(6) IU in adults, weekly. If there was a relapse, it was removed surgically and the patient returned to a higher dose level. Most cases (89; 71 per cent) have not relapsed after the treatment; 60 of them have been followed for more than three years. In those with relapses, the frequency of recurrence decreased in all but four patients. The treatment seemed to be more effective if initiated less than three months after the disease onset. The tracheostomy could be removed in five out of seven patients who needed it before the IFN treatment and was necessary in only three new cases during IFN treatment. In two of these, decannulation was possible later on. In a total of 14 patients relapses persisted after several cycles of IFN treatment. They were considered resistant to such treatment. No severe side effects were reported. The most frequent ones were fever, drowsiness, increased bronchial secretion, chills and headache. The establishment of this programme has maintained the disease under control in Cuba.
Gliomatosis cerebri (GC) is defined by the World Health Organization as a neoplasm of the glial cells. It is extremely rare, and there exists only 160 documented cases since 1897. There is no known treatment and the median survival rate is one year. The association of extracranial and CNS tumors is unusual, only three cases of breast cancer have been associated with gliomas and meningiomas but none with GC. Below we describe a case of breast cancer associated with GC and review the anatomoclinical and radiological manifestations of Gliomatosis Cerebri.
BACKGROUND: The syncytium-inducing (SI) viral phenotype and the emergence of viral strains resistant to zidovudine have been described in persons infected with HIV, and in some cases they have been associated with poor prognosis. METHODS: HIV isolates obtained from 37 HIV-infected children were analyzed to determine whether the SI viral phenotype and the mutation on the 215 position of the reverse transcriptase (M215) could be used as markers of disease progression. We performed peripheral blood coculture mononuclear cells, and we analyzed the induction of syncytia using the MT-2 cell line. The emergence of mutations on the 215 position was determined by PCR. RESULTS: We found a statistically significant association (P < 0.05) between SI viral phenotype and (1) recurrent serious bacterial infections, (2) absolute CD4+ cell counts <2 SD, (3) progression to AIDS and (4) death. Sixty percent of the children treated with zidovudine developed 215 mutant viral strains without statistically significant association with clinical or immunologic findings. The SI viral phenotype was statistically associated with the presence of the 215 mutation (P < 0.05). CONCLUSIONS: SI viral phenotype is a marker associated with a poor clinical and immunologic progression of the disease and it may facilitate the emergence of mutant strains in children treated with zidovudine.
Anaphylactic reactions after parasitized fish consumption are mediated by an IgE response. However, positive skin tests and specific IgE can also be found in many asymptomatic subjects who recognize a single medium-mol.-wt. antigen by IgE immunoblot. The study aimed to find out whether this unspecificity was due to the carbohydrate moieties of parasite antigens. Sixty-two patients with suspected parasite allergy, 51 blood donors, 18 bakers, and 38 atopic patients were studied by blotting. Parasite proteins were treated with periodate. Several selected sera were inhibited with a crude wheat extract and fungal amylase. Twelve patients (19%), eight donors (16%), six bakers (33%), and one atopic patient (3%) recognized a single medium-mol.-wt. band in blotting and should be considered false-positive. This band was periodate-sensitive, but specific IgE to this allergen could not be inhibited by a wheat extract nor by fungal amylase and was clinically irrelevant. Diagnosis of Anisakis simplex hypersensitivity by skin tests and/ or specific IgE values should always be confirmed by specific IgE immunoblotting in order to detect the presence of clinically unrelated antibodies directed to periodate-sensitive allergens. These allergens are probably not a carbohydrate moiety of a parasite glycoprotein.
Anisakis simplex, a parasite of fish and cephalopods, can induce IgE-mediated reactions. This study aimed to determine the etiologic role of A. simplex in patients affected by urticaria/angioedema (AE) or anaphylaxis. We studied 100 adult subjects suffering acute episodes of urticaria/AE, by anamnesis, prick tests with A. simplex and fish-mix extracts, and total and specific IgE to both A. simplex and cod. The following criteria of A. simplex allergy were considered: 1) urticaria/AE within 6 h after fish ingestion; 2) specific IgE to A. simplex; 3) positive prick test to A. simplex extract; 4) exclusion of other suspected causes. Double-blind, placebo-controlled food challenge was not carried out because ethical considerations forbid challenge with a parasite. Specific IgE to A. simplex (> 0.7 kU/l) was found in 22 subjects, but only eight were diagnosed as having A. simplex allergy. Other allergens were involved in 37 patients, and 55 cases were considered idiopathic. Specific IgE to fish (> 0.7 kU/l) was found in two patients, but only one was diagnosed as having fish allergy. We concluded that A. simplex is an important etiologic factor in acute urticaria. We suggest that it should be considered in cases of urticaria/AE or anaphylaxis, especially after fish ingestion.
Merino breed female sheep (225 in total) were used to study the effects of age and reproductive state on the values of 31 physiological parameters. Of these 31 parameters, 23 were affected by the age of animals, by their reproductive state, or by the interaction between these two factors. The statistical weighing of each of the factors of variability was determined. This revealed that the effects produced by them were indeed systematic. In order to demonstrate the systematic nature of the factors of variability, an attempt was made to classify each animal with respect to its reproductive state and age group, given only the set of biochemical values relating to it. The number of correct assignments to an age group achieved was 84.41%, and this rose to 92.17% with regard to reproductive state. A figure of 100% of correct assignments was reached with the adult age group and animals in oestrus. Thus, although the range of values observed for physiological parameters can, on occasions, be very large, this must be seen as a result of physiological deviations from average. These deviations are systematic and quantifiable, whether analysed in isolation or together as part of a multivariate analysis.
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Five genotoxicity studies on ebrotidine (N-[(E)-[[2-[[[2-[(diaminomethylene)amino]-4-thiazolyl]methyl]thio] ethyl]amino]methylene]-4-bromo-benzenesulfonamide, CAS 100981-43-9, FI-3542), including at least four of the battery of tests recommended by toxicological regulatory guidelines for new drugs, were conducted. These tests were the Ames test for determination of bacterial gene mutations, sex-linked recessive lethal mutation test in Drosophila for gene mutations in eukaryotic systems, in vitro chromosome aberration test and micronucleus test for evaluation of structural and numerical aberrations, and sister chromatid exchange frequency test for assessment of non-specific damage to chromatin. Negative and positive controls were used in all the experiments. The effects were investigated in the absence or presence of metabolic activation by S-9 microsomal fraction from rat liver homogenate. A dose range toxicity study was also performed to determine the dosage levels or concentrations to be tested for the assessment of genotoxic effects. None of the tests showed a significant increase in the genotoxic parameters, both in vitro and in vivo in somatic or germ cells. It is, therefore, concluded that ebrotidine has not caused mutagenic or clastogenic effects in any of the experimental systems tested.
A 14 years old patient, diagnosed in early childhood of type 1 Gaucher's disease is reported to show his unusual genotype and clinical course. The patient is heterozygous for mutation D409H, that in the homozygous patient determines an aggressive disease accompanied by neurological signs, and for a new mutation, which must be considered of mild effects. Early detection of bone involvement is emphasized as a factor to consider when indicating of enzyme replacement therapy.