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Biomedical subjects

A Lozano

Publications and source records attributed to A Lozano.

At least 73 records · Page 4Linked to original sources
PubMed1993

Combined therapy of coarctation and coronary heart disease in an adult.

The association of aortic coarctation and ischaemic cardiopathy is rare. We present a case of such an association in a 58-year-old patient with established spinal-cord damage and describe a one-stage surgical approach for the correction of both pathologies. Coarctation is solved by means of a supracoeliac to thoracic aortic bypass, and then coronary bypass grafting is performed under CPB. In this case grafts were carried out using the left internal mammary artery (IMA) even though it was hypertrophied. There were no postoperative complications and at 10 months the patient was asymptomatic.

Aorta, Abdominal↗
PubMed1993

A serological survey and review of clinical Lyme borreliosis in Spain.

A serosurvey for Lyme disease was conducted by the National Reference Center for Microbiology in Spain. All serum specimens received from patients with erythema migrans (EM), arthritis, and cardiac and neurological disorders were tested for antibodies to Borrelia burgdorferi. Sera from 499 patients were tested. Of these patients, 310 had neurological disease, 101 had carditis, 79 had arthropathies, and 9 had EM; for 35 patients, a diagnosis of Lyme disease was confirmed. Of these 35, 68% had neurological disease, 6% had carditis, and 26% had EM. Twelve probable cases of Lyme disease were noted. The male-to-female ratio of patients with confirmed or probable disease was 1.6; all age groups were represented, but 25% of patients were within the age group of 0-9 years. The number of cases of Lyme disease decreases from the north of Spain (41%) to the south (26%), a distribution that is in agreement with the known range of Ixodes ricinus. Borrelia burgdorferi is a frequent cause of infection in some areas of Spain. It is possible that relapsing fever accounts for some of the serological reactivity to B. burgdorferi in residents of the south of Spain.

Adolescent↗
PubMed1992

A broadband system for multifrequency static imaging in electrical impedance tomography.

A widely accepted method for static imaging in electrical impedance tomography (EIT) is to measure at two frequencies. The choice of measurement frequencies is application-dependent because some different tissues cannot be distinguished when using two fixed frequencies. We have developed a system that generates signals from 8-10(3) kHz and applies two of these signals simultaneously to the body through a broadband current mirror. Great care has been taken in the design of the current injection multiplexer in order to keep the current source output capacitance as low as possible. Furthermore design of the layout of the patient interface board, in order to reduce feedthrough capacitances, also needs great care. Other parameters for driving and detection sections have been designed according to our results from FEM and circuit simulations including skin and electrode effects. Simulations using FEM with available tissue impedance data and preliminary measurements in a discrete phantom show that static imaging is possible for both the real and imaginary parts of the impedance.

Electric Conductivity↗
PubMed1992

Epidemiology and prevalence of seropositivity against Borrelia burgdorferi antigen in La Rioja, Spain.

The aim of this study was to acquire a better knowledge of the epidemiology of Lyme disease. A seroepidemiologic study was made by evaluating the different levels of antibodies to Borrelia burgdorferi in a five hundred serum representative sample of a population from the province of La Rioja, Spain. Samples were randomly selected and stratified to take into account sex, age, rural or urban residence, and geographical area. All subjects included in the study were asked to fill out a questionnaire containing this information along with data concerning leisure activities, occupation, contact with animals, tick-bite and antecedent features related to Lyme disease. No statistical differences were found in relation to sex or age. The seroprevalence was very high (31.3%) in mountain areas, where Ixodes ricinus and deer are present. The risk factors associated with seropositivity were forestry and cattle-raising activities, as well as contact with animals. The best titer of antibodies associated with clinical antecedents of Lyme disease and related disorders was 1/256.

Adolescent↗
PubMed1990

Two-frequency impedance plethysmograph: real and imaginary parts.

A four-channel impedance plethysmograph has been designed. Impedance signals are obtained at two frequencies by measuring both real and imaginary parts. Particular attention has been paid to the sine wave generation circuits that provide system versatility. The required phase-sensitive demodulation is achieved by means of analogue multiplexers. Results show that there are significant variations in the thoracic equivalent capacitance related to respiration and that there is an increased sensitivity to cardiac activity at low frequencies.

Analog-Digital Conversion↗
PubMed1990

[Variation of bone density in relation to age: analysis of 259 necropsies].

In a previous study we reported a relatively low incidence of hip fracture in our population compared to figures reported elsewhere and speculated that this could be related to differences in bone density. Accordingly, we measured bone density in 259 subjects at necropsy. In 172 males we found that bone density decreased from 0.88 g/cc at age 21-30 to 0.80 at age 70 (NS). In women, density decreased from 1.0 at age 21-30 to 0.84 at age 50, 0.69 at age 60 and 0.64 in those older than 70 years (p less than 0.01). These figures are higher than those reported from USA at all ages and could explain the lower incidence of hip fractures in our population.

Adult↗
PubMed1990

[Postmenopausal women: changes in plasma lipids with different estrogen replacement therapies].

We measured total, HDL and LDL cholesterol and triglycerides in 183 postmenopausal women before and 4 weeks after hormone therapy. Ethinyl estradiol or conjugated estrogens alone or in association with medroxyprogesterone, norethyndrone or norgestrel were used in different dosages either continuously or sequentially. Total cholesterol decreased from 206 to 196 mg/dl and HDL raised from 47 to 53 mg/dl (p less than 0.001) except in the group treated with estradiol-levonorgestrel in which HDL fell from 41 to 36 mg/dl (p less than 0.001). HDL cholesterol decreased from 133 to 113 mg/dl, overall. The total cholesterol/HDL ratio decreased from 4.8 to 4.2 in all groups except the group previously mentioned. Estrogen therapy, isolated or in association to medroxyprogesterone induced a moderate increase in serum triglyceride levels (132 to 149 mg/dl, p less than 0.001). Thus, the administration of estrogens in postmenopausal women is associated with a decrease in total, LDL and total/HDL cholesterol ratio and an increase in triglycerides. Norgestrel but not medroxyprogesterone partially revert these effects.

Adult↗
PubMed1989

[Study of hearing in normally-hearing elderly patients. I. Auditory threshold].

Through this paper the AA. examine 504 ears of 252 subjects of both sexes, between 60 and 84, all feeling subjectively normal regarding this sense, without otologic conditions in the past or at present. The explorations done were air and bone tonal audiometry. At the time the results were assessed, the coefficient of variability and standard deviation were kept in mind.

Aged↗
PubMed1989

[Study of hearing in normally-hearing elderly patients. II. Supraliminal tests].

Five-hundred-and-four ears of 252 people, between 60 and 84 years of age have been tested. All of the group had supposedly good hearing, without otic antecedents and free of any complaint related to the ear. The tests done were: recruitment (Lüscher-Zwislocki), tone decay (Carhart) and automatic audiometry (von Békésy). In assessing the results, the coefficient of variability and standard deviation were kept in mind. Lastly, the AA. compare their own results with those attained in other published series.

Aged↗
PubMed1986

Familial mixed oligodendrocytic-astrocytic gliomas.

We present the first reported cases of mixed oligodendrocytic-astrocytic gliomas to occur in two members of the same family, a father and a son. These tumors had common biological and histological characteristics, and their occurrence supports the concept of genetic determination in some gliomas.

Adult↗
PubMed1984

Effect of 7-methylguanosine-5'-phosphate on the translation of rat milk-protein mRNAs in the wheat-germ cell-free system.

The translation of polyadenylated and of non-polyadenylated RNA obtained from lactating rat mammary gland was almost totally inhibited by 0.5 mM 7-methylguanosine-5'-phosphate in the wheat-germ cell-free system. This inhibition was maintained during the preparation of the 9S whey-protein mRNA and of the 12S and 15S casein mRNAs. Chemical decapping of these mRNAs caused a similar reduction of their activity. Although a large fraction of milk-protein mRNAs have been reported to lack 3'-polyadenylation, these results show that the mRNAs in the mammary gland do contain a 5'-terminal 7-methylguanosine cap.

Animals↗