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Biomedical subjects

S Cabrera

Publications and source records attributed to S Cabrera.

84 records · Page 5Linked to original sources
PubMed2000

TIMP-1, -2, -3, and -4 in idiopathic pulmonary fibrosis. A prevailing nondegradative lung microenvironment?

Fibroblast proliferation and extracellular matrix accumulation characterize idiopathic pulmonary fibrosis (IPF). We evaluated the presence of tissue inhibitor of metalloproteinase (TIMP)-1, -2, -3, and -4; collagenase-1, -2, and -3; gelatinases A and B; and membrane type 1 matrix metalloproteinase (MMP) in 12 IPF and 6 control lungs. TIMP-1 was found in interstitial macrophages and TIMP-2 in fibroblast foci. TIMP-3 revealed an intense staining mainly decorating the elastic lamina in vessels. TIMP-4 was expressed in IPF lungs by epithelial and plasma cells. TIMP-2 colocalized with Ki67 in fibroblasts, whereas TIMP-3 colocalized with p27 in inflammatory and epithelial cells. Collagenase-1 was localized in macrophages and alveolar epithelial cells, collagenase-2 was localized in a few neutrophils, and collagenase-3 was not detected. MMP-9 was found in neutrophils and subepithelial myofibroblasts. Myofibroblast expression of MMP-9 was corroborated in vitro by RT-PCR. MMP-2 was noticed in myofibroblasts, some of them close to areas of basement membrane disruption, and membrane type 1 MMP was noticed in interstitial macrophages. These findings suggest that in IPF there is higher expression of TIMPs compared with collagenases, supporting the hypothesis that a nondegrading fibrillar collagen microenvironment is prevailing.

Aged↗
PubMed2000

[Changes in the profile of HIV-positive patients. What has happened in the last 5 years?].

OBJECTIVE: To evaluate possible changes in the social, cultural and economical profile of our HIV infected patients appearing during the last five years and their potential impact on incidence, prevention, and follow-up of HIV infection. METHODS: We conduce a retrospective analysis of demographic, sociocultural, clinical and therapeutic characteristics of two groups of HIV infected patients reaching for the first time a level of 300 CD4 or less either in 1992 or in 1997. RESULTS: 55 patients with a mean age of 33 years (68% male 32% female) were studied. No differences were found in sexual behavior, HIV status of sexual partner, cultural level, risk practice, VHB or YHC seroprevalence. Attempts al drug quitting in 1992 were made individually and through institutional programs in 1997. Significant differences were found in the number of visits to the outpatient clinic the previous 36 months, and in de number of drugs (1.5 versus 3.5 P < 0.0001). Antirretroviral drugs were use in 62% of our 1992 patients and in 86% of the 1997 group (p < -0.02). CONCLUSIONS: The sociocultural and demographic profile has not changed in our environment in the last five years. However patients were identified later and followed less regularly at our clinic five years ago. Institutional methadone programs are the method or choice in our current patients for stopping illicit drug use. Finally treatment intensity has dramatically increased in our patients parallel to the growing therapeutical arsenal in this field.

Adult↗
PubMed1999

Race-specific HIV-1 disease-modifying effects associated with CCR5 haplotypes.

Genetic variation in CC chemokine receptor 5 (CCR5), the major HIV-1 coreceptor, has been shown to influence HIV-1 transmission and disease progression. However, it is generally assumed that the same CCR5 genotype (or haplotype) has similar phenotypic effects in different populations. To test this assumption, we used an evolutionary-based classification of CCR5 haplotypes to determine their associated HIV-1 disease-modifying effects in a large well-characterized racially mixed cohort of HIV-1-seropositive individuals. We demonstrate that the spectrum of CCR5 haplotypes associated with disease acceleration or retardation differs between African Americans and Caucasians. Also, we show that there is a strong interactive effect between CCR5 haplotypes with different evolutionary histories. The striking population-specific phenotypic effects associated with CCR5 haplotypes emphasize the importance of understanding the evolutionary context in which disease susceptibility genes are expressed.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Variations in UV radiation in Chile.

The first observations of UV global radiation in Chile with a portable multichannel radiometer are reported. Four UV wavelengths are included: 305, 320, 340 and 380 nm. Observation latitudes spanning from 18 degrees to 53 degrees S allow an estimation of latitudinal variations in daily maxima for both summer and winter. Measurements over Santiago deviate from a smooth latitudinal profile, probably as a consequence of urban air pollution. The main effect of this is to prevent UV solar radiation from reaching the ground, especially during winter. Altitudinal increments in UV radiation are estimated by comparing observations along the coast and valleys with others on the Andes and one isolated summit. Diurnal variations in the height increment support an increase from morning to evening. The results indicate that in rural areas the altitudinal increment is lower (4%-10% per kilometre) than that reported for Europe, reaching very low magnitudes (2% or less) in the Andean summits of desert regions.

Chile↗
PubMed1994

[Effects of A and B ultraviolet irradiation on human lymphocytes].

Over the last decade, a greater decrease in the ozone level has occurred in the Southern Hemisphere. For each 1% decrease in this level, a 2% increase in biologically effective radiation occurs. Aiming to evaluate the biological effect produced by UV radiation, 10 blood samples coming from patients consulting for reproductive problems, were irradiated with visible and ultraviolet radiation A (treatment A) and visible and ultraviolet radiation B (treatment B) during 1 to 5 minutes. This dosage is comparable to the radiation received in Santiago at 13:00 h in a summer day. After irradiation, lymphocytes were cultured during 72 h and the number of altered metaphases was quantified. There was a significant increase in chromosomal alterations with treatment A (2.61, 2.43, 4.53 and 3.53 at 1, 2, 3 and 5 min respectively) and treatment B (3.06, 3.81, 3.3, 5.51, at 1, 2, 3 and 5 min respectively) compared with non-irradiated controls (0.8 and 0.72). There was a reduction in mitotic indices in irradiated cells. It is concluded that both types of UV radiation (A and B) produce chromosomal alternations in vitro, even using lower doses than those received during summer in the central region of Chile.

Chromosomes↗
PubMed1989

Sporotrichosis in the Orinoco river basin of Venezuela and Colombia.

Six cases of sporotrichosis from the Orinoco river basin of Venezuela and Colombia are described; two are of the localized cutaneous type and four are lymphocutaneous. Diagnosis was based on the patient's clinical history and mycological culture. Epidemiology and distinctive cultural habits of the patients are discussed in connection with disease etiology.

Adolescent↗
PubMed1983

Effects of garlic extract and of three pure components isolated from it on human platelet aggregation, arachidonate metabolism, release reaction and platelet ultrastructure.

We studied the effect of the methanol extract of garlic bulbs (EOG) and of three pure components isolated from it (F1, F2, F3), on human platelet aggregation induced by ADP, epinephrine, collagen, thrombin, arachidonate, PAF, and the ionophore A-23187. Incubation of PRP with EOG, either in methanol or in homologous PPP, inhibits platelet aggregation induced by all of the above mentioned agonists. F1, F2, and F3 also inhibit platelet aggregation, however, F3 was about four times more potent. Addition of EOG or F3 to platelets that have already been irreversibly aggregated by 10 microM ADP, induces rapid deaggregation. Inhibition of aggregation was still present after three hours. The inhibitory effect persisted even after the treated platelets were Gel-Filtered (GFP) or separated from plasma through a metrizamide gradient and resuspended in new homologous PPP. Thrombin-induced release of ATP from GFP was inhibited by 75-80% after EOG or F3 treatment. Incorporation of [3-H]-arachidonate by intact platelets was decreased by 50-60% in treated platelets. However, platelets incubated with the inhibitors after incorporation of radiolabeled arachidonate, although did not aggregate, produced, after thrombin activation similar amounts of radiolabeled TXB2 and lipoxygenase products as the controls. Electron microscopy of inhibited platelets, in the presence of thrombin, showed no degranulation but an increase of spherical forms. Our results suggest that the effects described might be mediate by a perturbation of the physicochemical properties of the plasma membrane rather than by affecting arachidonate or calcium metabolism in the cells. Chemical structures of F1, F2 and F3 have been provisionally assigned: F1 is diallytrisulfide, F2 is 2-vinyl-1,3-dithiene, and F3 is most probably allyl 1,5-hexadienyltrisulfide.

Adenosine Diphosphate↗
PubMed1977

Follow-up evaluation of drug abuse treatment.

Several fundamental issues in the design and planning of a follow-up evaluation are introduced. Many factors, including the design of the questionnaire, relationship to the subject, and confidentiality policies, determine both the rate and validity of the responses. Utilizing the described planning the supervision, staff time can be minimized, and estimates are given for both mailed and personal interviews. A variety of specific tracking techniques is outlined which facilitate the location of subjects who cannot be found at formerly listed addresses.

Follow-Up Studies↗
PubMedDate not supplied

Ozone and UV radiation over southern South America: climatology and anomalies.

Ozone and UV radiation were analyzed at eight stations from tropical to sub-Antarctic regions in South America. Ground UV irradiances were measured by multichannel radiometers as part of the Inter American Institute for Global Change Radiation network. The irradiance channels used for this study were centered at 305 nm (for UV-B measurements) and 340 nm (for UV-A measurements). Results were presented as daily maximum irradiances, as monthly averaged, daily integrated irradiances and as the ratio of 305 nm to 340 nm. These findings are the first to be based on a long time series of semispectral data from the southern region of South America. As expected, the UV-B channel and total column ozone varied with latitude. The pattern of the UV-A channel was more complex because of local atmospheric conditions. Total column ozone levels of < 220 Dobson Units were observed at all sites. Analysis of autocorrelations showed a larger persistence of total column ozone level than irradiance. A decreasing cross-correlation coefficient between 305 and 340 nm and an increasing cross-correlation coefficient between 305 nm and ozone were observed at higher latitudes, indicating that factors such as cloud cover tend to dominate at northern sites and that ozone levels tend to dominate at southern sites. These results highlight the value of long-term monitoring of radiation with multichannel radiometers to determine climatological data and evaluate the combination of factors affecting ground UV radiation.

Journal Article↗