[Medical care in Santiago, 1993]

Results of morbidity and medical care surveys performed in Santiago in 1993-94 are presented in this paper. The study has been done in an aleatory population sample of 4,700 people coming from 1,000 dwellings. Main results are as following: The Health National Fund (FONASA) is the most important financing medical care's agency in Santiago (49% out of total population). A majority of medical services are given in private offices or clinics. Medical care systems show significant differences among the studied city districts. A significant direct correlation between people's income and private practice is noticed. One half of acute diseases had medical care and the other half used self care practices; the proportion of medical care is 29% in the case of chronic disease patients. National Health Service eligible people show a significant higher morbidity rate and medical consultation rate than other groups. Lack of medical care mainly depends on low severity of illness episodes or lack of symptoms in chronic disease conditions. In 12% out of total cases, lack of medical care was due to problems in the medical care systems. The quality of care was judged "good or excellent" by 82% of the people, "fair" by 9%, and "bad or deficient" by the remaining 8%. Personal expenditures due to health care are high, one third depending on medical care and two thirds on dental care. In the case of medical care the reasons for expenditures are linked to chronic diseases (60%), acute diseases (28%), injuries and health examinations (15%). Main activities causing personal disbursements are the purchase of drugs (44%), medical visits (30%), laboratory tests (13%) and hospital charges (7%).(ABSTRACT TRUNCATED AT 250 WORDS)

[Characteristics and management of morbidity in Santiago 1993]

Results of morbidity and medical care surveys of the Santiago's population are presented in this paper. A random sample of 1,000 dwellings with 4,700 people was selected and studied 3 times, in 1993 and 1994. All health events (acute and chronic morbidity, health examinations, dental care) and main features of medical care were registered in the interviews which covered a 2-week period each time. The population sample had similar characteristics than the results of the last Population and Dwellings Chilean Census. Health events were registered with high frequency: 56% of the families had one or more members with chronic disease; 51% with acute diseases; 46% with emotional troubles; 24% had dental care; 17% health examination and 6% different types of injuries. Frequency of medical care during the fortnight period was 5.6% out of total population of acute diseases; 1.0% of injuries; 4.9% for chronic diseases, 3.9% of health examinations and 5.6% of dental care. Frequency of diseases was significantly higher among women (50%) than in men (33%) and in poor people than in higher socioeconomic levels. Most of the acute disease were respiratory illnesses followed by communicable diseases, skin troubles and rheumatologic disorders. The most important detected chronic diseases were blood hypertension, diabetes mellitus, bronchial asthma and alcoholic addiction.(ABSTRACT TRUNCATED AT 250 WORDS)

Recurrence rate after accessory pathway ablation

OBJECTIVE

To evaluate characteristics of patients and accessory pathways as well as additional technical factors involved in the reappearance of accessory pathway conduction after successful ablation.

DESIGN

Analysis of recurrences after radiofrequency ablation.

SETTING

163 consecutive patients with 167 accessory pathways.

SUBJECTS

97 men and 66 women with a mean (SD) age of 36 (14) range (11 to 75) years.

RESULTS

After a mean (SD) follow up of 14 (7) range (2 to 27) months, conduction recurred in 13 out of 167 (7.8%) accessory pathways. The initial manifestation of recurrence was circus movement tachycardia in 7 patients and reappearance of delta waves on a 12 lead electrocardiogram in 6 patients. The interval to the return of accessory pathway conduction ranged from 3 hours to 90 days. Age, sex, presence of multiple accessory pathways, criteria to determine the target ablation site, number and duration of radiofrequency applications, and cumulative energy did not significantly differ between the groups with recurrence and without. Recurrence was less common with concealed accessory pathways (2/44) than with overt accessory pathways (11/110). The difference was not significant. The only variable to influence the recurrences in this study group was the location of the accessory pathway. Reappearance of conduction through right sided accessory pathways occurred significantly more often than through left sided ones (8/40 v 5/114, P = 0.01).

CONCLUSION

After radiofrequency ablation the recurrence rate of accessory pathways is low and there are no predictors of the risk of reappearance of conduction apart from the right sided location of the accessory pathway.

Photosynthesis and water relations of savanna tree species differing in leaf phenology

Godmania macrocarpa Hemsley, a deciduous tree characteristic of fire protected areas of the savanna region of central Venezuela, was more drought tolerant, allocated more N to leaves and had consistently higher photosynthetic rates than Curatella americana L., a ubiquitous species growing successfully within the grasslands of tropical American savannas. Godmania macrocarpa maintained higher leaf conductance and photosynthesized at higher xylem water tensions than C. americana. As the dry season progressed, G. macrocarpa was more affected by water stress than C. americana, which may explain why G. macrocarpa shed its leaves before forming new leaves. For both species, leaf sap osmolality was strongly correlated with, but not completely accounted for by, soluble sugars. Integrated water-use efficiency, as measured by delta(13)C, was similar for both species, but young leaves were more efficient than old leaves. Water-use efficiency of adult leaves was similar in both species as a result of higher photosynthetic rates in G. macrocarpa and lower leaf conductances in C. americana. Compared to G. macrocarpa, instantaneous photosynthetic N-use efficiency was higher in C. americana despite its lower maximum photosynthetic rates. The absence of G. macrocarpa trees from open grasslands, despite their high productive capacity, is possibly the result of unfavorable conditions for germination, poor survival of seedlings, and lack of resistance against fire.

[Attitudes and behaviour concerning tobacco use among physicians from Santiago]

The aim of this work was to study the prevalence, behavior and opinions towards smoking in a sample of 288 physicians from Santiago, stratified according to sex and specialty. The WHO Europe questionnaire was applied and smoker was defined as the person that consumed one or more cigarettes per day. Thirty six percent of the sample (40.2% of men and 23.8% of women) smoked an average of 9 cigarettes per day, compared to the figure of 28.3% obtained in a similar study in 1983. Fifty percent of smokers felt that they will not quit. No differences in knowledge about problems associated to smoking or forbidding smoking in hospitals, were observed between smokers and non-smokers. A majority of smokers did not smoke in front of their patients and did not allow smoking in their private clinics. It is concluded that, although a high proportion of physicians continue to smoke, their opinions and behavior will support smoking cessation efforts.

Flow cytometric analysis of the stimulatory response of T cell subsets from normal and HIV-1+ individuals to various mitogenic stimuli in vitro

A novel technique is described which allows the study of the responses of T cell subpopulations stimulated in bulk cultures without interfering with cell-cell interactions. The number and phenotype of lymphoblasts developing following stimulation with phytohaemagglutinin (PHA), anti-CD3, staphylococcal protein A (SPA) and pokeweed mitogen (PWM) was determined in HIV-1- and HIV-1+ patients using a new five-parameter flow cytometric method. We found that normal T cells responded faster to PHA than to any of the other mitogens tested. The peak of the PHA response occurred on day 3, followed by anti-CD3 and SPA on day 4 and PWM mitogen on day 5. Although PHA and anti-CD3 stimulated up to 95% and 80% of lymphocytes, respectively, SPA and PWM stimulated only 40% and 30% of cells, respectively. A defective T cell response was observed in lymphocytes cultured from asymptomatic HIV-1+ patients compared with negative controls. This loss of response was related to a selective mortality of T cells following mitogenic stimulation, referred to as activation-associated lymphocyte death (AALD). The results showed that stronger mitogens (PHA and anti-CD3) induced AALD in a larger proportion (50-60%) of T cells than weaker mitogens such as SPA and PWM (30-40%), and that AALD affected different lymphocyte subsets to different extents. AALD occurred more frequently in total CD8+ and CD45RO+ T cells compared with CD4+ and CD45RA+ T cells, but memory CD4+ T cells were the population most severely affected in samples from HIV-1+ donors.

[Celebration of the 50th anniversary of the School of Public Health of the University of Chile]

The joined initiative of the University of Chile, the Health institutions, the Bacteriological Institute and the Rockefeller Foundation support allowed the creation of the School of Public Health. A group of skilled and talented young specialists gave rise to the School, as an expression of the need to refurbish the medical care of the forties. The aim of the School was to communicate the scientific basis of sanitary practice, to study national problems and to group people that can contribute to improve the health status of the country. During fifty years, the number of Chilean and foreign students expanded considerably. During these five decades the School has trained 1588 specialists (459 foreigners) in Public Health. The School was awarded by WHO in 1988 in recognition of its outstanding contributions to Public Health. It is difficult to make adequate decisions at the present time, due to the complexity of Chilean health situation, that is going through an epidemiological and demographic transition. A systematic effort to investigate and to train people in public health and health administration is mandatory. These are the principal tasks of the School, that maintains its fifty years tradition left by its founders.

Lymphocyte activation in HIV-1 infection. II. Functional defects of CD28- T cells

OBJECTIVES AND DESIGN

The expression of the accessory molecule CD28 was compared in various populations of T and natural killer (NK) cells from HIV-1-negative and HIV-1-positive individuals and correlated with activation using mitogens in vitro.

METHODS

Multiparameter flow cytometric analysis using combinations of CD3 CD28 and other markers was performed together with absolute cell counting in peripheral blood. Blast transformation and proliferative responses were also quantitated using the Cytoronabsolute after stimulation with phytohaemagglutinin (PHA) and anti-CD3. CD28- cells were also purified to confirm the observations.

RESULTS

In HIV-1-negative individuals > 90% of CD3+ T cells were CD28+ and responded to stimulation, while CD3- CD16+ CD57+ NK-like cells were CD28- and failed to respond. In HIV-1-positive individuals the expression of CD28 was greatly reduced and the proportion of CD3+CD28- T cells expanded. CD8 lymphocytosis was caused entirely by the accumulation of CD28- T cells and many of these expressed activation markers human lymphocyte antigen-DR, CD38 and CD45RO on their membrane and molecules such as TIA-1 and perforin, associated with cytolytic function, in their cytoplasm. The strong positive correlation (r = 0.66) between the lack of CD28 expression and the poor proliferation from HIV-1-positive individuals was confirmed by demonstrating that only CD28+ cells transformed into lymphoblasts and proliferated. Although the CD28- including CD3+ T cells transiently expressed CD25 (interleukin-2R alpha), they did not undergo blastogenesis or activation measured by bromodeoxyuridine uptake and died after 3-4 days in culture. These observations were confirmed in costimulation experiments with anti-CD2 and anti-CD28.

CONCLUSION

In HIV-1 infection activated CD3+CD28- T cells accumulate but are unresponsive to mitogens and anti-CD28. These cells appear to represent terminally differentiated effector cells which fail to respond to further stimuli because of the absence of a CD28 second signal.

[Active epidemiologic surveillance of tuberculosis]

With 5,000 new active cases each year, tuberculosis in Chile remains as the most important communicable disease in the country. Since the type of control programs are linked to the epidemiologic situation as far as infection, morbidity and mortality are concerned, an effective surveillance system is needed, with analysis of the general data and an active search for other evidences which show the advantages and problems of the control programs. The number of active cases shows a downward trend with 66 new cases per 100,000 population in 1982 and 37 in 1992. nevertheless, in Santiago, comparing years 1991 and 1991, an increase of 4% in morbidity, 37% of mortality and 33% in the case fatality rate are observed. Morbidity rates are variable with highest numbers in the I Region of Tarapacá probably linked to the prevalent ethnic type of the population. One quarter out of total tuberculosis deaths depends on the late effects of the disease and three quarter are the consequences of recent active disease. People over 55 years of age represents 25% out of total new cases. Besides classical indicators it is important to consider the frequency and results of the practice of diagnostic laboratory tests; the antibiotic therapy resistance; the results of the treatment, analyzing cohorts of treated people; the importance of different infection factors; the evaluation of BCG immunization; the meaning of animal tuberculosis infection; the slowness in the beginning of treatment in new cases; the results of the screening of high risk population and the systematic analysis of each death due to tuberculosis.

Arthroscopic lysis in knee arthrofibrosis

Arthrofibrosis continues to be a difficult complication in articular surgery on the knee. We present our experience in 21 cases of arthroscopic lysis as an alternative to mobilization under anesthesia. The technique begins with the liberation of the adhesions of the suprapatellar pouch, continues down both gutters, and ends with a cleaning of the notch where necessary. When a restriction of patellar mobility persists, we make a retinacular release. The results obtained are very satisfactory, with an average increase in the arc of mobility of 68 degrees. The average gain in mobility at 6 months is significantly greater than that achieved in the immediate postoperative period. Longer follow-up showed no improvement in range of motion after 6 months.

[Long-term survival of patients with stomach cancer treated with subtotal gastrectomy]

The aim of this work was to determine the 5 and 12 years survival of 233 patients with gastric cancer subjected to subtotal gastrectomy. Patients with early gastric cancer (n = 51) had a 95% survival and those with intermediate cancer (n = 19) a 87% survival. Patients with advanced gastric cancer (n = 163) subjected to curative surgery had a 60% survival, whereas none subjected to palliative surgery survived. Those patients that survive more than 24 months after the surgical procedure, have an excellent long term prognosis.

[Liver cirrhosis in Chile: epidemiologic considerations]

Liver cirrhosis is an important public health problem in Chile, accounting for 5% of all deaths, proportion that has increased 24 fold in the last 60 years. Chile has the highest death rate for cirrhosis in America and the second highest in the world, after Hungary. The risk of death and hospitalization for cirrhosis has increased significantly between 1950 and 1970, stabilizing thereafter in values near to 50 hospitalizations and 30 deaths/year per 100,000 inhabitants. The risk for cirrhosis is higher among men and increases with age. Among people between 35 and 60 years of age, cirrhosis is the first or second cause of death and the third among those aged 60 to 69 years. The age of patients hospitalized for cirrhosis has increased from 42.7 years in 1950 to 55.5 in 1990. Among women, cirrhosis appears at older ages than in men. Mortality rates vary in the different regions of the country and range from 55 in Concepcion and Talcahuano to 8 per 100,000 inhabitants in Coquimbo. The certainty of Chilean information on cirrhosis and the evidences associating cirrhosis to alcohol consumption are discussed, being prominent the significant association between annual death rates for cirrhosis and wine production.

[Diagnostic value of aspiration cytology with ERCP]

ERCP is of great value in diagnosing malignant pathology of the biliopancreatic duct system. However, the ERCP endoscopic characteristics in malignant stenosis often lack specificity and are difficult to differentiate from those of chronic pancreatitis. In these cases histological confirmation is essential to diagnosis. With the aim of increasing the diagnostic possibilities of ERCP in pancreatic cancer--particularly when associated with chronic pancreatitis--we performed aspiration cytology of pancreatic juice obtained via endoscopic cannulation of the main pancreatic duct using ERCP in 102 patients with suspected periampullar pathology, chronic pancreatitis and/or pancreatic cancer. The diagnostic sensitivity of cytology for pancreatic malignancy was 33.3%, versus 60% for cancer of Vater's papilla. Specificity was 100% in both cancers. We observed no false positive results or complications. On combining both techniques, i.e., ERCP and cytology of the pancreatic juice, sensitivity increased to 100% for pancreatic malignancy, 77.7% for chronic pancreatitis (characteristic ERCP radiographic images and absence of neoplastic cells) and 100% in the case of ampullomas. Difficulties in the differential diagnosis between advanced chronic pancreatitis and pancreatic cancer persist with ERCP alone. In such cases aspiration cytology may secure a definitive diagnosis--particularly when neoplastic cells are demonstrated (Class IV).

[Biliary surgery mortality in Chile in 1990. Cooperative study in 17 hospitals]

A survey about surgical procedures performed in 1990 was answered by 17 surgical services. With these data the operative mortality of biliary surgery was analyzed. During 1990, 39,643 patients were subjected to major surgery of which 9,654 (24.3%) corresponded to benign biliary tract diseases. Forty nine percent of patients had chronic cholecystitis, 36% acute cholecystitis and 16% choledocholithiasis. Global mortality of these procedures was 0.58% and mortalities for chronic cholecystitis, acute cholecystitis and choledocholithiasis were 0.06, 0.6 and 2% respectively. These numbers increased significantly in patients over 60 years old, are lower than those reported 10 years ago and could be useful as "gold standards" for laparoscopic cholecystectomy.

[Long-term results of endoscopic sphincterotomy]

A review is made of the results of long-term endoscopic sphincterotomy. We studied 81 endoscopic sphincterotomies performed between 1980 and 1985. The technique performed, its indications and immediate complications were evaluated, along with the follow-up carried out in these patients (minimum 6 years). In view of the results obtained, the patients were classified as asymptomatic or symptomatic. Thus, immediate complications (21.9%) were all minor, with the exception of one case (1.2%) of severe complication due to acute pancreatitis. One death was recorded three days after sphincterotomy, corresponding to an elderly patient with in situ gallbladder as a consequence of biliary sepsis. In turn, 91.4% of the patients followed-up at long term remained asymptomatic. The overall results show the method to be effective, with few either immediate or long-term complications.

Lymphocyte activation in HIV-1 infection. I. Predominant proliferative defects among CD45R0+ cells of the CD4 and CD8 lineages

OBJECTIVES AND DESIGN

The proliferative defects of CD4 and CD8 cells taken from 474 HIV-1-seropositive individuals during various stages of disease were quantitated. Phytohaemagglutinin (PHA) and soluble anti-CD3 were used in optimal mitogenic concentrations in the presence of recombinant interleukin-2 (rIL-2) and conditioned medium, and the proliferation of cells from HIV-1-seropositive donors was assessed in co-culture with HIV-1-seronegative cells in order to exclude effects of cytokine deficiency. Defects within the CD45RA+ ('unprimed') and CD45R0+ ('primed') T-cell populations were also investigated.

METHODS

Quantitative immunofluorescence and double and triple labelling in flow cytometry were performed for (1) CD25 (IL-2 receptor alpha chain) expression, (2) lymphocyte and T-cell survival, and (3) blast transformation and proliferation--in relation to the original input of cells for each subpopulation.

RESULTS

T cells from normal and HIV-1-seropositive donors were CD25+ at day 1. In HIV-1-seropositive patients a variable number of CD4 and CD8 lymphocytes failed to further increase CD25, and died as a sign of activation-associated lymphocyte death (AALD). Forty-two per cent of asymptomatic subjects, including 32% of those with CD4 cell counts > 400 x 10(6)/l, showed a poor blast transformation (< 30% blasts). Cells from HIV-1-seropositive donors showed poor blast responses when co-cultured with HIV-1-seronegative cells; both CD4 and CD8 cells were handicapped. In asymptomatic HIV-1-seropositive people T cells with the CD45R0+ RA- ('primed') phenotype were three to five times more vulnerable to AALD than the CD45RA+ RO- ('unprimed') cells. In patients in Centers for Disease Control and Prevention (CDC) disease stage IV both CD45R0+ and -RA+ populations were severely affected.

CONCLUSIONS

This is the first quantitative analysis to demonstrate that in HIV-1 infection mitogen-stimulated CD45R0+ ('primed') T cells preferentially die upon activation. Both the CD4 and CD8 lineages are affected, as seen in animal models of graft versus host disease. AALD may explain defects of immunological memory. The analysis of AALD may be a suitable assay for studying whether antiviral drugs influence the proliferative responses of lymphocytes.

Multihormonal response to CRH in a patient with Cushing syndrome and a pituitary adenoma producing ACTH and GH

Preoperative bilateral and simultaneous catheterization of the inferior petrosal sinuses was performed in a patient with Cushing's syndrome. This procedure revealed parallel intersinus gradients for ACTH, PRL, GH and a response of all these hormones to CRH. The patient had transphenoidal surgery and a soft white-yellowish mass occupying the whole sella conditioned a total hypophysectomy. Morphologic studies and immunostaining techniques revealed a rare mixed pituitary adenoma of ACTH and GH containing cells and failed to demonstrate PRL immunoreactivity in the tumor cells. These results are of clinical and speculative interest. Whether GH and PRL secretion in response to CRH stems from the tumor or reflect hormone release by non-tumor cells via a paracrine effect remains to be defined.

[Treatment of mild hypertension with captopril and captopril with hydrochlorothiazide. Impact on blood pressure values and quality of life]

The effects of captopril alone or associated to hydrochlorothiazide on blood pressure and quality of life was studied in 244 hypertensive subjects. After a medication wash out period of 30 days (and 7 additional days when diuretics were used) patients were treated initially with captopril 25 mg b.i.d. (scheme A); if blood pressure was not normalized, hydrochlorothiazide 25 mg o.d. was added (scheme B) and the dose of captopril was increased to 50 mg bid (scheme C) in a stepwise fashion. Sixteen patients (6.6%) were lost from follow up; in the rest a significant reduction of blood pressure was obtained at the end of the treatment period (from 163/98.9 +/- 19.7/3.1 to 143/85 +/- 12.7/6.7 p < 0.05), without changes in cardiac frequency. Using captopril alone, blood pressure was normalized at 15 and 75 days in 62.9 and 70.6% of patients respectively. With captopril plus hydrochlorothiazide blood pressure was normalized in 80.9% of patients. Quality of life improved significantly from of 42.8 +/- 1.7 to 50.7 +/- 15 score points (p < 0.05) secondary effects were observed in 7.4% of patients. It is concluded that captopril alone or associated to hydrochlorothiazide is effective in the treatment of mild hypertension, produces few secondary effects and improves the quality of life.

[Hospitalization in Chile: a critical analysis]

Main features of hospital stay in Chile are analyzed with special regard to incidence, geographic, sex and age variations, main causes and trends observed in the last decades. The annual admission rate in 1989 was 107 per 1000, twice the overall Latin American rate. Wide variations are observed among geographical areas, with relatively low use of hospital beds in the capital city of Santiago. Hospital needs differ for men and women and according to age, being greater for infants, older people and women of childbearing age. Near two thirds of the needs are related to pregnancy. Admissions for traumatic, digestive, respiratory, urinary and gynecological problems are also frequent. Accidents are the main cause for hospital admission among males, while tumor is foremost among women. During the last 30 years the hospitalization rate has remained stable while the case fatality rate has decreased. Different factors influencing the frequency and features of hospital stay are discussed.

[Primary care for adults in Chile: analysis of basic information]

According to national data the Chilean adult population on the average has 2.5 annual ambulatory visits with an increasing trend in the last decade. The figure has significant variation in the diverse geographic regions. Taking pregnant women out, main diseases assisted at the outpatient departments of general consultation include in a 70%, problems usually of the competence of internal medicine specialists. The solving problem capacity in these departments is 80 to 85% which means that 15-20% of the patients needs to be referred to a higher complexity medical care level. According to the National Health Service experience, two-thirds of the primary care level are done by general practitioners and one-third by specialists. A scarce preventive component and a low coverage of chronic disease among adult people and the problems of the primary care in the National Health Service are commented. A new structure of medical care levels is proposed separating a first level with include rural and basic urban outpatient clinics besides low complexity hospitals with general practitioners; a second level with urban general outpatient clinics served with specialists and median complexity hospitals; and a third level with new and specialized ambulatory centers for diagnosis and treatment and hospitals of high and great complexity.