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Biomedical subjects

A Bulla

Publications and source records attributed to A Bulla.

At least 19 recordsLinked to original sources
PubMed1990

Experimental obstructive coronary atherosclerosis in the hyperlipidemic hamster.

The evolution of coronary atherosclerotic lesions induced by a hyperlipidemic diet was examined in male hamsters subjected for up to 40 weeks to a standard chow supplemented with 3% cholesterol and 15% butter. Control animals were fed standard chow only. Five to seven hamsters were monthly sacrificed and investigated for serum lipids and coronary artery lesions. As compared with control animals, the hamsters fed the fat diet showed a progressive increase in serum cholesterol which reached maximum values up to 17 fold in the 10th month. The serum of the hyperlipidemic hamster examined by agarose electrophoresis, Laurell immunoelectrophoresis and cross-immunoelectrophoresis showed at most a 14 fold increase in low density lipoproteins after 10 months diet. The examination of coronary arteries revealed morphologic changes already detectable at 2 weeks of diet. The earliest modifications observed were characterized by proliferation of the subendothelial matrix or/and the appearance of liposome-like structures in the intima. After 2-3 weeks of diet, smooth muscle cells appeared occasionally in the intima and monocytes adhered and penetrated through the endothelium. Later on, smooth muscle cells and macrophage displayed lipid deposits. Focally, in areas of intimal proliferation and foam cells, endothelial cells were also lipid-loaded. Like in human atherosclerotic plaque, in the late stages of hamster coronary lesions, there was a progressive accumulation of extracellular unesterified cholesterol, calcium deposition and necrosis. Lesions evolved to a progressive narrowing of the coronary branches affected, with complete obstruction of some small arterial ramifications. Hamster appears to be a suitable model for studying the molecular and cellular events leading to obstructive coronary atherosclerosis.

Animals↗
PubMed1987

The hyperlipidemic hamster as a model of experimental atherosclerosis.

Male hamsters were fed a hyperlipidemic diet consisting of standard chow supplemented with 3% cholesterol and 15% commercial butter for 12 months. In about 3 weeks serum total cholesterol doubled, raised 4-fold after the 4th week and after 10 months attained a 17-fold value. Low density lipoproteins (LDL)-cholesterol increased 4-fold after 4 weeks and about 13-fold after 10 months compared to control animals. In the first 2 weeks mononuclear cells began to adhere to the endothelium and a very intense stromal reaction appeared in the intima of the aortic arch. At the end of the 4th week of diet, Oil Red O stainable deposits were visible on the thoracic aorta, mostly on the arch, some of them as isolated, lipid-laden cells and others distributed on focal areas. Smooth muscle cells (SMC) appeared also in the intima of hyperlipidemic hamsters, compared to normal animals which had no macrophages or smooth muscle cells in the intima of the aortic specimens examined. Up to 6 months, smooth muscle cells in the intima and media began to load with lipids, as well as endothelial cells. After 10 months the affected zones looked like human atherosclerotic plaque with huge cholesterol crystal deposits, calcium deposits and necrosis. The endothelium, though very thinned and loaded with lipids, was morphologically intact.

Animals↗
PubMed1987

Cellular events in the development of valvular atherosclerotic lesions induced by experimental hypercholesterolemia.

The onset and evolution of ultrastructural changes in the cardiac valves induced by a cholesterol-rich diet were investigated in rabbit and hamster. In both animal models, the atrioventricular and sigmoid valves were comparably affected by lesions intermediary between fatty streak and fibrous plaque. The earliest detectable modification was the progressive accumulation in the subendothelium of extracellular liposome-like structures rich in unesterified cholesterol, associated with the proliferation of a basal lamina-like material. This was followed by the diapedesis of blood monocytes in the same location, which became macrophages increasingly loaded with lipid deposits. Resident interstitial cells accumulate lipids, as well. In advanced stages, the macrophage-derived foam cells clustered, deforming the valve leaflets. The resident macrophages accumulated lipids later and more slowly, while partly preserving their ultrastructure. The advanced lesions are characterized by marked stromal proliferation, massive intra- and extracellular deposition of lipids and cholesterol crystals and the appearance of a necrotic core. The salient findings of these studies were: (1) the appearance of extracellular liposomes as the earliest event in atherogenesis; (2) the capability of the valvular interstitial cells to accumulate lipids; and (3) the slow response of resident macrophages to the cholesterol-rich diet. The results revealed that hypercholesterolemia produces in the cardiac valves atherosclerotic lesions of an intermediate type, which can deform the leaflets thus altering their normal function.

Animals↗
PubMed1986

The exceedingly high burden of acute and chronic respiratory diseases--global situation and prospects.

Mortality data are presented for acute and chronic respiratory diseases, on a world-wide basis for the period 1970-1982, encompassing 76-88 countries, with a population of 1.1-1.3 billion. Despite the declining trend of respiratory conditions, mortality from acute respiratory infections is still rampant at the two extremes of the lifespan and pneumonia attains unacceptably high mortality rates in developing countries. Chronic respiratory diseases claim a significant proportion of lives in the old age groups in both developed and developing countries. It is now sufficient evidence that respiratory diseases are preventable and the reduction of mortality is possible through appropriate intervention programmes.

Adolescent↗
PubMed1985

Plasma exchange-induced biological stress of the Hagemann-mediated systems: results of contact activation and plasma substitution.

Plasma exchange can induce changes in the biological systems of coagulation, fibrinolysis, complement and kinins, either by contact activation or plasma substitution. In order to know which of the two is responsible, the actual initial and final values and theoretical calculated final values were compared. Fibrinogen, Antithrombin III and platelets fell more than expected, and there was a significant increase in Platelet-Factor four and Betathromboglobulin which was greater than would produced by plasma substitution alone. Fibrinolysis is shortened and white cells rise. Complement and kinins were not significantly changed. During plasma exchange, contact activation actually triggers coagulo-fibrinolytic pathway and stresses cellular components.

Adult↗
PubMed1983

Activation of the coagulation system and leukocytes kinetics in plasma exchange.

The activation of the coagulation system--commonly occurring in other extracorporeal circulation--is still debated, in plasma exchange (PE), data being conflicting due to the different types of replacement fluid used in 25 patients treated by PE using a discontinuous plasma separator (14 with freshly-frozen plasma, 8 with half plasma half 5% albumin, 3 with only 5% albumin). The occurrence of leukocytes stress is proved by their marked increase at the end of the procedure while the platelet fall is superimposable to the HTC fall. A coagulation-fibrinolytic activation seems to be demonstrated by plasma increase in endoplatelet constituents, fibrinogen and antithrombin III consumption, and shortening in fibrinolytic tests, but caution must be made in interpreting these results because the donor's plasma units show high levels of platelet endogranular constituents and a wide variable range of coagulation-related proteins, which can interfere with an appropriate evaluation of the results.

Blood Coagulation↗
PubMed1981

Coagulation and fibrinolysis study in systemic lupus erythematosus: haematological, urinary and tissue parameters.

Haematochemical, urinary and tissue parameters were examined in the elaboration of the coagulation and fibrinolysis profile in 33 cases of systemic lupus erythematosus in different stages of the disease. Coagulation abnormalities varied from hypo- to hyper-coagulability, these being often associated in the same patient, either simultaneously or at different stages of the disease. Activation of coagulation, closely related to the immunological activity of the disease, was present in 80% cases in the acute stage, and 36% of those in the remission stage. The lupus-like anticoagulant was not much involved, and platelets were the prime figures in the haemostatic abnormalities of lupus, those being the preferred target of direct antibody activities, or possibly of immune complexes as well. Activation of the coagulatory cascade is not uncommonly accompanied by a thrombophilic tendency coupled with signs of consumption, this being the expression of a continuously stimulated haemostatic balance.

Autoantibodies↗
PubMed1978

Acute respiratory infections: a review.

Acute respiratory infections (ARI) constitute one of the principal causes of morbidity and mortality in many countries. Data from 88 countries in five continents, with a total population of nearly 1200 million, showed that deaths due to ARI in 1972 amounted to 666 000. Pneumonia, both viral and bacterial, accounted for 75.5% of the total deaths from ARI. Mortality from ARI represents 6.3% of deaths from all causes. Considerable differences in mortality rates exist both between and within continents. Mortality from ARI is highest in infants and old people. The data suggest that in some areas of the world mortality due to ARI is extremely high.

Acute Disease↗
PubMed1977

[Global review of tuberculosis morbidity and mortality in the world (1961-1971)].

The main objective of gathering available world-wide information on tuberculosis is to present an overall picture of how tuberculosis infection, morbidity and mortality, can be reflected today and to suggest the necessity to improve international epidemiological statistical intelligence. The highest levels of tuberculosis infection in the world (i.e. 60-80% in children 14 years old) may be found in eastern Asia, Oceania and in several areas in Africa. Considerable differences still do exist between the highest and lowest prevalence level within each continent. The ratio between the highest and lowest prevalence level of infection is varying from 1 to 2 in the Americas, to 1 to 10 in Europe. While, in general, in developed countries the annual infection rate reached 0.5% (1969-1972), in developing countries, annual infection rates of 2% or more were reported. The decrease of the annual infection rate in developed countries is, in general, 10% each year, whereas in the developing part of the world the fall in the rates has been slower or the level even remained constant for the last ten years. The information concerning tuberculosis morbidity is sometimes incomplete or inconsistent because of the lack of standard criteria for diagnosing and reporting tuberculosis. Although the bacteriological confirmation of tuberculosis cases has an important bearing on the recording system, official reports are particularly deficient in this respect. Estimating the total number of newly registered tuberculosis cases, one may say that more than 3.8 million, and approximately 4 million cases could have occurred 1967 and 1971 respectively. The prevalence of tuberculosis cases can be estimated to be around 6-8 in 1967 and 8 million cases in 1971. The highest incidence rates reported in 1971 were in Asia, Oceania and in some African countries (i.e. 250-523 per 100000 population). In Europe and America, tuberculosis incidence did not exceed a level of 200 per 100000 population. The average tuberculosis incidence rate for 1971 in the world may be estimated to be 111.5 per 100000 population (111.4 in 1967).

Adolescent↗
PubMed1977

[Trends in tuberculosis hospital and sanatorium beds throughout the world (1960-1975)].

The most important problem facing phthisiologists in the past was how to ensure a sufficient number of sanatorium beds for the management of tuberculosis patients, their rehabilitation and the prevention of transmission of infection by isolating them. There is considerable evidence today, however, that the results obtained with ambulatory treatment are as good as those following in-patient treatment. The latter is now considered unnecessary as it serves merely to prolong duration of the patient's incapacity and to increase the cost of treatment. The presentation of the available information on the trend of beds designated for tuberculosis aims at stimulating the new approach to efficient control of the disease so as to prevent the misuse of available resources. During the period 1960-1965 there were more than 870000 tuberculosis beds reported in the world. Between 1970 and 1975, the number of tuberculosis beds was reduced to 609000. The average percentage of tuberculosis beds to the existing total bed complement was 8.4 in 1960-1uberculosis bed density"--was 3.9 and 3.1 respectively, for the two periods. Owing to the very large variety of reporting systems and sometimes to their defective patterns, international comparisons are hazardous. In general, there is a considerable declining trend in the tuberculosis bed density, in countries with a high initial level, whereas in other countries an upwards trend is sometimes to be found. The analysis of the particular patterns of tuberculosis bed density is difficult, as in many countries the still existing high bed density is actually a combined tuberculosis and respiratory diseases bed density. In countries with a well developed network of institutional units, treatment costs account for approximately half the total cost of the tuberculosis control programme. In a broad public health sense bed strategy is becoming increasingly important since apart from the substantial capital cost of institutional facilities, it also influences both the pattern of service rendered and the use of resources available.

Africa↗