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Biomedical subjects

A Salazar

Publications and source records attributed to A Salazar.

At least 37 records · Page 2Linked to original sources
PubMed2001

Rat hepatic stellate cells contribute to the acute-phase response with increased expression of alpha1(I) and alpha1(IV) collagens, tissue inhibitor of metalloproteinase-1, and matrix-metalloproteinase-2 messenger RNAs.

The acute-phase response (APR) represents a systemic reaction of the organism to multiple nonspecific inflammatory stimuli. In general, it is protective for the host, and hepatocytes are the main cells responding with alterations in the expression of a set of liver-specific proteins named the acute-phase proteins. We have previously shown that although a turpentine-induced APR is not fibrogenic per se, it enhances collagen deposition in rats treated with CCl(4) and up-regulates expression of hepatic alpha1(I) collagen and tissue inhibitor of metalloproteinases 1 (TIMP-1) messenger RNAs (mRNAs). In this report we extended our studies and showed that turpentine induced, in a time-dependent manner, expression of alpha1(I) and alpha1(IV) collagens, TIMP-1, and matrix-metalloproteinase 2 (MMP-2) mRNAs. We further showed that expression of these mRNAs occurs in hepatic stellate cells, but not in hepatocytes obtained 6 hours after the induction of an APR episode. These changes were accompanied by increased blood levels of tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6) without noticeable immediate changes in the expression of their respective mRNAs in the liver. In contrast to CCl(4)-induced liver damage, turpentine alone, whether administered as a single dose or as a weekly dose for 3 weeks did not up-regulate expression of transforming growth factor beta1 (TGF-beta1) mRNA and did not result in excess collagen deposition. Overall, these findings suggest that collagen deposition in the livers of rats with repeated APR episodes may be enhanced only when given together with a fibrogenic stimulus that activates hepatic stellate cells (HSCs) and/or up-regulates TGF-beta1 mRNA expression.

Acute-Phase Reaction↗
PubMed2001

Impact of a resident strike on emergency department quality indicators at an urban teaching hospital.

OBJECTIVE: To evaluate the indicators of activity and quality within the emergency department (ED) during a resident physicians' strike. METHODS: This was an observational study comparing a strike period (SP) and a non-strike period (NSP) in the ED of a 1,000-bed tertiary care teaching hospital in Barcelona, Spain, with an annual census of 100,000 emergency visits. During a period of nine nonconsecutive days, the resident physicians were on strike. Emergency visits were handled by staff members. Data were compared between all patients treated in the ED during the SP and those treated during the NSP, matched by the weekday. The authors compared lengths of stay (LOSs), rates of use of laboratory tests and radiology procedures, numbers of patient walkouts, patient/physician ratios, emergency hospital admission rates, home discharge rates, unscheduled return rates, and mortality rates. RESULTS: The two groups (SP 2,610 patients and NSP 3,634 patients) were comparable in terms of average daily attendance rate (SP: 290 +/- 12 vs NSP: 302 +/- 21; p = 0.13), elective hospital admission rate, and severity of illness. Statistically significant differences were found in terms of mean total patients' LOS (SP: 206.75 +/- 12.27 vs NSP: 235.10 +/- 27.08 minutes; p < 0.001), number of laboratory tests per patient (SP: 0.30 +/- 0.05 vs NSP: 0.38 +/- 0.04; p < 0.001), and radiographs per patient (SP: 0.78 +/- 0.06 vs NSP: 0.88 +/- 0.09; p = 0.021). CONCLUSIONS: This study demonstrated that replacing residents with staff physicians resulted in fewer laboratory tests ordered, fewer radiographs ordered, and shorter lengths of stays in the ED.

Adult↗
PubMed2000

Influence of serum amyloid A on the decrease of high density lipoprotein-cholesterol in active sarcoidosis.

OBJECTIVE: We have previously observed low levels of high density lipoprotein (HDL) cholesterol in active sarcoidosis. The aim of this study was to analyze the role of serum amyloid A (SAA) on this lipid disorder. METHODS: Eighty five untreated sarcoid patients, 40 with active disease and 45 with inactive disease, were recruited. Sarcoidosis activity was evaluated by means of clinical, chest X-ray, gallium-67 scan, serum angiotensin converting enzyme (peptidyl-dipeptidase A) values, and pulmonary function tests. Analysis of lipoprotein metabolism included: serum cholesterol, low density lipoprotein (LDL)-cholesterol, HDL-cholesterol, HDL(2)-cholesterol, HDL(3)-cholesterol, apolipoprotein A-I (apo A-I), apolipoprotein B (apo B), and triglyceride concentrations. Serum amyloid A protein and lecithin-cholesterol acyltransferase (LCAT) activity were measured. RESULTS: In active sarcoidosis we found significantly reduced levels of HDL-cholesterol (1.17+/-0.36 vs. 1. 44+/-0.39 mmol/l, P=0.002), HDL(3)-cholesterol (0.78+/-0.23 vs. 1. 02+/-0.21 mmol/l, P<0.0001), and apo A-I (1.36+/-0.29 vs. 1.61+/-0. 27 g/l, P<0.0001) and significantly increased levels of triglyceride (1.51+/-0.64 vs. 1.03+/-0.46 mmol/l, P<0.0001), and apo B (1.14+/-0. 25 vs. 0.99+/-0.27 g/l, P=0.012) versus inactive sarcoidosis. Serum amyloid A concentrations were significantly increased in the patients with active disease (155.45+/-154.01 mg/ml) compared to the inactive sarcoid patients (89.70+/-65.36 mg/ml) (P=0.011). There were no significant differences in cholesterol, LDL-cholesterol, HDL(2)-cholesterol or LCAT values between groups. Multivariate logistic regression analysis showed that HDL-cholesterol (regression coefficient b=-1.96; S.E.=0.87; P=0.02) and SAA (regression coefficient b=0.01; S.E.=0.004; P=0.01) were the two variables independently associated with disease activity. Moreover, a significant negative correlation was observed between SAA levels and both HDL-cholesterol (r=-0.39; P=0.01) and apo A-I (r=-0.35; P=0.03) levels, in the active sarcoid group. Conversely, no correlation was found in the inactive sarcoid group. CONCLUSION: The low HDL-cholesterol and apo A-I concentrations seen in active sarcoid patients are associated with a significant increase of SAA levels. We suggest that the displacement of apo A-I by SAA on HDL accounts for the lower level of HDL-cholesterol seen in active sarcoidosis.

Adult↗
PubMed2000

Creating knowledge structures in the pharmaceutical industry: the increasing significance of virtual organisation.

This paper explores the specific trend and challenges facing the pharmaceutical industry regarding the exploitation of Internet e-commerce technology and virtual organisation to develop and maintain competitive advantage. There are two important facets of the current trend. One is the rapid development of a complex network of alliances between the established pharmaceutical companies and the specialised biotechnology company start-ups. The other is the rapid growth of internet e-commerce companies dedicated to developing specialised technological platforms for acquiring and selling genetic and biochemical knowledge. The underlying challenge is how big pharmaceutical companies can emulate some of the innovation processes of smaller biotechnology company start-ups, and how they can appropriate and applied new technological knowledge on the development of new drugs. Pharmaceutical companies in order to retain competitive advantage need to continuously monitor all aspects of knowledge management with regard to the R&D and manufacturing process (as well as customer management and marketing). Technological change and organisational restructuring should be aimed at boosting the capacity of large firms to innovate rapidly.

Drug Industry↗
PubMed1999

Löfgren's syndrome revisited: a study of 186 patients.

PURPOSE: To evaluate the clinical features, the results of noninvasive tests and biopsies, and the outcome of patients with Löfgren's syndrome. SUBJECTS AND METHODS: Patients diagnosed as having Löfgren's syndrome at a university hospital in Barcelona, Spain, from 1974 to 1996, were prospectively followed. Löfgren's syndrome was defined as the association of erythema nodosum or periarticular ankle inflammation with unilateral or bilateral hilar or right paratracheal lymphadenopathy. RESULTS: Löfgren's syndrome was diagnosed in 186 patients. The mean age was 37 +/- 11 years, and 157 (85%) were women. In 91 patients (49%), symptoms started during the spring (P < 0.0001). Erythema nodosum, periarticular ankle inflammation, or both were present at onset in 173 patients (93%). At the time of diagnosis, 161 patients (87%) had no respiratory symptoms; 151 (81%) had stage I abnormalities on chest radiograph, 29 (16%) stage II, and 6 (3%) stage 0. Five percent of patients had decreased forced vital capacity, and 15% had decreased carbon monoxide diffusing capacity. Extrathoracic involvement was infrequent. Serum angiotensin-converting enzyme levels were increased in 50% of patients. Gallium-67 scans showed hilar uptake in all the studied patients, but it yielded useful additional diagnostic information only in those with normal chest radiographs or with unilateral hilar lymphadenopathy. The diagnosis was proven with biopsy results in 63% of patients. None of the patients without histologic confirmation were subsequently found to have a diagnosis other than sarcoidosis. In the 133 patients who were followed for a mean of almost 5 years, 11 (8%) continued to have active disease, and 8 (6%) had several recurrences between 18 months and 20 years after a complete resolution. A normal serum angiotensin-converting enzyme level at diagnosis was associated with disease resolution without recurrence. CONCLUSION: Löfgren's syndrome is usually a self-limiting form of sarcoidosis. Histologic confirmation is not necessary in typical cases. In a small number of patients, the disease may remain active or recur long after its onset, although usually with mild organ dysfunction.

Adolescent↗
PubMed1999

Repeated measures of cognitive processing efficiency in adolescent athletes: implications for monitoring recovery from concussion.

OBJECTIVE: The objective of this study was to determine whether an adolescent athlete, in the absence of concussion, would be expected to show an improvement in cognitive function during the course of a high school football season. BACKGROUND: At least 60,000 American high school football players suffer cerebral concussion every year, and symptoms may persist for 4 or more years in as many as 24%. METHOD: 34 members of a cohort of healthy athletes, aged 13-18, were administered a computerized neuropsychologic test battery from the Automated Neuropsychological Assessment Metrics (ANAM) before and after the 1997 high school football season, with a mean interval of 16.1 (range 12.3-20.4) weeks between tests. Preseason and postseason scores on eight tests were compared, with significance determined by paired t-test. For those tests in which an improvement was noted, one-way analysis of variance and Wilcoxon tests were used with both preseason and postseason data to determine if there was a measurable difference in cognitive processing efficiency between older and younger subjects. RESULTS: Improvements in processing efficiency (p < 0.001) were noted on tests designed to measure visual scanning and sustained attention (CDS), immediate recall (CDI), and short-term memory (CDD). Older subjects generally performed better on each of these tests, though the difference was significant in only one case (postseason CDI, 17-18 year olds vs. 13-14 year olds, Wilcoxon, p = 0.043). CONCLUSIONS: Our findings suggest that ANAM is sensitive to differences and improvements in cognitive function during a 4 month interval in adolescence. They also suggest that using "return to baseline" cognitive function as the criterion for evidence of recovery from concussion may be insufficient, especially when the baseline measurement was obtained 4 or more months prior to the date of "full recovery."

Adolescent↗
PubMed1999

Effect of powder-free latex examination glove use on airborne powder levels in a dental school clinic.

Cornstarch powder on latex examination gloves acts as an airborne carrier of natural latex allergens resulting in cutaneous, conjunctival, and/or respiratory responses to latex, a particular concern in a dental school environment where concentrated use of latex examination gloves occurs. This study measured airborne powder levels associated with a trial substitution of powder-free latex examination gloves for powdered latex examination gloves in a dental school clinic. Secondary aims of the study were to assess user acceptance of powder-free gloves during the trial and to assess the financial impact of converting the entire dental school to a powder-free environment. Air was sampled from two areas (dispensary and treatment room) of a student clinic fifteen to thirty minutes before the beginning of normal clinic sessions and again about 1.5 hours into the clinic session. The samples were microscopically analyzed for particulate counts of cornstarch powder. A written survey instrument assessed user acceptance of the two types of gloves. Historical financial data were used to estimate the cost of converting the entire dental school to a powder-free environment. Both the dispensary and the treatment room showed significant reductions in airborne powder counts during use of powder-free latex gloves and a return to high powder counts with resumption of powdered glove use. During the weeks of powdered glove use, the powder counts were also significantly lower before the beginning of the clinic session and higher during the clinic session. User acceptance of the powder-free latex gloves was high. The increased cost per year to convert the entire dental school to a powder-free environment was estimated to be $13,943.

Air Pollutants, Occupational↗
PubMed1998

Treatment with anti-transforming growth factor beta antibodies influences an altered pattern of cytokines gene expression in injured rat liver.

The role of transforming growth factor beta1 (TGF-beta1) in mediating hepatic inflammation and regeneration after acute liver injury is beginning to be elucidated, yet its in vivo effect on the gene expression of the major pro-inflammatory and anti-inflammatory cytokines produced during that process is unknown. Our previous experiments demonstrated that anti-TGF-beta-treated animals presented profound histological changes as compared with control animals. Therefore, our hypothesis was that by blocking in vivo TGF-beta1 action, with polyclonal anti-TGF-beta antibodies, we could monitor by RT-PCR significative alterations on the gene expression of IL-1beta, IL-6, TGF-beta, TNF-alpha, IL-4 and IL-10 in liver-regenerated rats after administration of a single CCl4 dosing. Accordingly, we here report a completely different pattern of cytokines gene expression amidst those groups of rats. Pro-inflammatory cytokines gene expression in control animals showed a clear-cut pattern peaking at 1-2 days postinjury and declining thereafter. Interestingly, IL-6 was present in the control animals only between 12 and 24 h after CCl4 dosing. In the experimental animals, TGF-beta1 was mainly increased at 4 and 6 days, while IL-6 mRNA was completely absent. IL-1beta mRNA expression was also altered in the experimental rats, albeit TNF-alpha was nearly unaffected. IL-4 was fully absent in control rats, but remarkably expressed in experimental animals throughout the study. IL-10 was also more expressed in experimental animals.

Animals↗
PubMed1998

Biophysical linkage between MRI and EEG amplitude in closed head injury.

Nuclear magnetic resonance of brain water proton (1H) T2 relaxation times and measures of absolute amplitude of EEG were obtained from 19 closed head injured patients. The relationship between EEG and T2 relaxation time differed as a function of both EEG frequency and gray matter versus white matter. White matter T2 relaxation time was positively correlated with increased EEG amplitude in the delta frequency band (0.5-3.5 Hz). In contrast, lengthened gray matter T2 relaxation time was inversely correlated with EEG amplitude in the alpha and beta frequency bands (7-22 Hz). These findings are consistent with clinical EEG studies in which white matter lesions are related to increased EEG delta amplitude and gray matter lesions are related to decreased EEG alpha and beta frequency amplitude. Estimates of the severity of injury were obtained by neuropsychological measurements, in which lengthened T2 relaxation times in both the neocortical gray and white matter were correlated with diminished cognitive function. Decreased EEG beta and alpha amplitude and increased EEG delta amplitude were also correlated with diminished cognitive function. The findings imply a biophysical linkage between the state of protein-lipid structures of the brain as measured by the MRI and the scalp-recorded EEG.

Adult↗
PubMed1998

Biophysical linkage between MRI and EEG coherence in closed head injury.

Using conventional MRI procedures, nuclear magnetic resonance (NMR) of brain water proton (1H) T2 relaxation times and EEG coherence were obtained from two independent groups of closed head injured (CHI) patients and a group of normal control subjects. Statistically significant intercorrelations were observed between 1H T2 relaxation times of the cortical gray and white matter and EEG coherence. The analyses showed that lengthened 1H T2 relaxation times of the cortical gray and white matter were related to: (1) decreased EEG coherence between short interelectrode distances (e.g., 7 cm) and increased EEG coherence between long interelectrode distances (e.g., 28 cm), (2) differences in EEG frequency in which T2 relaxation time was most strongly related to the gray matter in the delta and theta frequencies in CHI patients, and (3) increased T2 relaxation time and decreased short-distance EEG coherence were related to reduced cognitive function. The results were interpreted in terms of reduced integrity of protein/lipid neural membranes and the efficiency and effectiveness of short- and long-distance neural synchronization following traumatic brain injury.

Adolescent↗
PubMed1998

Low levels of high density lipoprotein cholesterol in patients with active sarcoidosis.

OBJECTIVE: To determine lipoprotein abnormalities in patients diagnosed with sarcoidosis and their relation to disease activity. METHODS: We studied 90 patients with biopsy-proven sarcoidosis who had not been treated with corticosteroids (44 with active disease and 46 with inactive disease) and 147 control subjects. Sarcoidosis activity was evaluated by means of clinical, chest X-ray, gallium-67 scan, serum angiotensin converting enzyme (peptidyl-dipeptidase A) values, and pulmonary function tests. Analysis of lipoprotein metabolism included: serum cholesterol, low density lipoprotein (LDL)-cholesterol, high density lipoprotein (HDL)-cholesterol, HDL2-cholesterol, HDL3-cholesterol, apolipoprotein A-I, apolipoprotein B, and triglyceride concentrations. RESULTS: Patients with active sarcoidosis had significantly low HDL-cholesterol concentrations (1.15 +/- 0.27 mmol/l) as compared with inactive sarcoid patients (1.40 +/- 0.34 mmol/l) and with the healthy control subjects (1.49 +/- 0.34 mmol/l) (p = 0.00001). The decrease in the HDL-cholesterol concentrations seen in patients with active disease was due mainly to the cholesterol bound to HDL2 subfraction. Apolipoprotein A-I concentrations were significantly reduced in the patients with active disease (1.18 +/- 0.32 g/l) compared to the healthy controls (1.38 +/- 0.27 g/l) (p = 0.003). There were no significant differences in cholesterol, triglyceride, LDL-cholesterol or apolipoprotein B values among the three groups. Multivariate logistic regression analysis showed that HDL-cholesterol was the only variable independently associated with disease activity (Regression Coefficient b = -0.03; S.E. = 0.008; p = 0.0005). CONCLUSION: The decrease in HDL-cholesterol that is observed in patients with sarcoidosis is limited to those with active disease.

Apolipoprotein A-I↗
PubMed1997

Cutaneous involvement in sarcoidosis. Relationship to systemic disease.

Sarcoidosis is an antigen-mediated disease defined by granuloma formation in different organs. It involves mainly the mediastinal and peripheral lymph nodes, lungs, eyes, skin, liver, and spleen. Cutaneous lesions of sarcoidosis may be specific, showing histologically noncaseating granulomas, or nonspecific, most typically erythema nodosum. Frequently, both types of skin lesions are the means of presentation of the disease and may contribute to the diagnosis. A workup for systemic sarcoidosis should be undertaken in every patient with sarcoid cutaneous granulomas. Some types of cutaneous lesions have prognostic significance. Lupus pernio and plaques are associated with more severe systemic involvement and more chronic course, while erythema nodosum is the hallmark of acute and benign disease.

Acute Disease↗
PubMed1997

Quantitative MRI of the gray-white matter distribution in traumatic brain injury.

Quantitative analyses were performed on magnetic resonance images (MRIs) obtained from the brains of 31 traumatic brain-injured (TBI) patients and 25 normal control subjects. The quantitative analyses involved comparisons of the shapes of proton density gray scale pixel histograms obtained from both 3-mm and 5-mm slice thickness. Image segmentation was accomplished by a multispectral fuzzy C-means and/or k-nearest-neighbor (kNN) algorithms and manual classification was used to label segmented classes into CSF, white matter, and other. Shape descriptors were derived from the pixel intensity histograms of the combined gray matter and white matter classes for each MRI slice. Statistical analyses revealed significant differences in pixel intensity distributions between TBI and control subjects. Normal control subjects tended to exhibit bimodal gray matter-white matter histograms, whereas, TBI patients tended to exhibit unimodal gray matter-white matter histograms. In the control subjects the pixels intermediate in intensity between gray and white matter were located primarily at the border between the gray and white matter, whereas TBI patients exhibited a thickening of the number of intermediate pixels at the border as well as an increase in intermediate pixels in the middle of the gray and white matter. The greater the severity of TBI, then the larger the number of intermediate intensity pixels within and between gray and white matter. Further analyses demonstrated shifts in magnetic resonance relaxation times in gray and white matter in TBI patients, which suggested that the tendency toward unimodality in TBI patients represents a pathological reduction in brain differentiation due to measurable biophysical change.

Adult↗
PubMed1997

Continuous wavelet transform of aortic pressure oscillations in anesthetized dogs: effects of 45 degrees tilting.

The time-frequency analysis of signals by means of continuous wavelet transform (CWT) was applied to blood pressure oscillations recorded from the aorta of anesthetized dogs. This method yielded two and three-dimensional representations of either the module or phase in function of time, in contrast with the fast Fourier transform (FFT) which gives the spectrum in the frequency domain. From the CWT of arterial pressure oscillations we obtained visual information on aortic valves closure, heart rate, respiratory rate and smooth muscle contractions in arterial and arteriolar walls (very low frequency component). The objective of this study was to analyze the frequency-time behavior in two and three-dimensional cardiovascular changes during 45 degrees head-up and head-down tilts, compared with zero degree supine position. In eight pentobarbitone anesthetized dogs, the postural changes were repeated for more than ten times in each one. Heart rate variability was derived by applying a new mathematical procedure. We utilized the pronounced changes of heart rate during each respiratory cycle (inspiratory tachycardia and expiratory bradycardia) to establish a correlation with the arterial pressure fluctuations during normal and tilting conditions. Significant differences in heart rate were observed between the 45 degrees head-up and head-down tilts, compared with the supine position. The results show that anesthetized dogs might constitute an appropriate model where to study orthostatic hypotension and microgravity blood shifts.

Anesthesia↗
PubMed1997

Thrombin and its precursor in human cerebrospinal fluid.

The blood coagulation cascade proteolytic enzyme, thrombin, affects many cell types, including neurons and astrocytes, in which it prevents process outgrowth and induces significant morphological degeneration and even cell death. Since thrombin may contribute significantly to pathological conditions in the central nervous system (CNS), where it is synthesized locally, we measured the levels of thrombin and its precursor, prothrombin, in the cerebrospinal fluid (CSF) of 67 individuals from 6 groups: non-neurologic controls (NNC); spinal degenerative disease (SDD); peripheral nerve disease (PND); cerebrovascular, neuroimmune and seizure disorders and tumor (CNSD); traumatic brain injury (TBI) and neurodegenerative disorders (NDD). We employed a sensitive chromogenic assay utilizing the thrombin specific tripeptide substrate, S-2238, to evaluate CSF levels of thrombin and prothrombin. The latter estimated after its conversion to active enzyme by the snake venom prothrombinase, ecarin. No measurable active thrombin was detected in these CSF samples. However, activatable prothrombin was measured in all groups. The mean activatable prothrombin concentrations (in nM) were 7.26 +/- 3.39 (NNC); 8.85 +/- 3.09 (SDD); 6.78 +/- 2.58 (PND); 6.33 +/- 3.87 (CNSD); 5.10 +/- 1.86 (TBI), and 7.80 +/- 3.27 (NDD). Duncan's multiple comparison test showed significant reduction (p <0.05) in prothrombin levels of the TBI group. Our data suggests that the prothrombin zymogen gains access to the CSF, likely across either an intact or compromised blood-brain barrier (BBB), in increased amounts with age. Reduced levels in TBI patients may have diagnostic and/or prognostic value.

Adult↗
PubMed1997

[Estimate of the prevalence of Huntington disease in the Valencia region using the capture-recapture method].

INTRODUCTION AND OBJECTIVE: The objective of this study was to estimate the prevalence of Huntington's disease in order to devise a programme for diagnosis and prevention. Because of the characteristics of this disease, which is hereditary and of low incidence, few epidemiological studies have been carried out in Spain. Many studies (Medline 1990-1996) give cross-checking of registers as the key to determining the relative extent of the illness. The findings of this comparison of registers are not limited to the numerical quantification of a health problem, but are combined with active case search strategies, since there is now an approximation of probability to a previously unknown area of the disease. MATERIAL AND METHODS: Prevalence in the Valencia Region (Spain), which has a population census of 3,873,812 inhabitants, was estimated by means of the probability method known as capture-recapture. The estimated maximum probability and its confidence interval were calculated. The sources of information used were clinical histories from the regional hospitals and official figures of registered deaths during the period 1987-1992. RESULTS: It was found that there were 41 cases seen in the regional hospitals and 17 deaths recorded in the official statistics, while 4 cases coincided in both sets of statistics. Recovery of 45 cases histories enabled an analysis to be made of the relationship between the disease, sex, age of onset of symptoms, and family history. CONCLUSION: The estimated prevalence was 5.38 x 10(5). The most notable finding was that of a systematically earlier onset of symptoms in women, which was greater when the family history was on the paternal side.

Adult↗
PubMed1996

The distribution of fallout 137Cs in Costa Rica.

Baseline levels of 137Cs on different sites throughout the Costa Rican territory are presented in this study from local and undisturbed soils. They are believed to represent the fallout input to the land surface. Seventy samples were collected from September 1991 to December 1993, and analyzed by gamma spectroscopy. The territory was divided in three regions, Caribbean, Pacific, and Central, based on meteorological and geographical conditions to study spatial distribution of cesium. The results show a higher activity in the Caribbean region perhaps due to the wind influence and higher rain precipitation throughout the year. No relevant time variation of the activity levels for each location was found. The highest value of 17.6 Bq kg(-1) of 137Cs is compared with its generalized derived limit, being only 1.97% of the generalized derived limit value. The mean country activity value ranges from 0.4 to 17.8 Bq kg(-1) with an average of 3.7 Bq kg(-1).

Cesium Radioisotopes↗