PubMed Health⌕ Search

Biomedical subjects

I Libman

Publications and source records attributed to I Libman.

At least 19 recordsLinked to original sources
PubMed2002

Structure characterization of human serum proteins in solution and dry state.

The present report describes application of advanced analytical methods to establish correlation between changes in human serum proteins of patients with coronary atherosclerosis (protein metabolism) before and after moderate beer consumption. Intrinsic fluorescence, circular dichroism (CD), differential scanning calorimetry and hydrophobicity (So) were used to study human serum proteins. Globulin and albumin from human serum (HSG and HSA, respectively) were denatured with 8 m urea as the maximal concentration. The results obtained provided evidence of differences in their secondary and tertiary structures. The thermal denaturation of HSA and HSG expressed in temperature of denaturation (Td, degrees C), enthalpy (DeltaH, kcal/mol) and entropy (DeltaS kcal/mol K) showed qualitative changes in these protein fractions, which were characterized and compared with fluorescence and CD. Number of hydrogen bonds (n) ruptured during this process was calculated from these thermodynamic parameters and then used for determination of the degree of denaturation (%D). Unfolding of HSA and HSG fractions is a result of promoted interactions between exposed functional groups, which involve conformational changes of alpha-helix, beta-sheet and aperiodic structure. Here evidence is provided that the loosening of the human serum protein structure takes place primarily in various concentrations of urea before and after beer consumption (BC). Differences in the fluorescence behavior of the proteins are attributed to disruption of the structure of proteins by denaturants as well as by the change in their compactability as a result of ethanol consumption. In summary, thermal denaturation parameters, fluorescence, So and the content of secondary structure have shown that HSG is more stable fraction than HSA.

Blood Proteins↗
PubMed2001

Beer consumption and changes in stability of human serum proteins.

The aim of this study was to evaluate the influence of beer consumption (BC) on the functional and structural properties of human serum proteins (HSP). Thirty-eight volunteers (after coronary bypass) were divided into two groups: experimental (EG) and control (CG). Nineteen volunteers of the EG consumed 330 mL per day of beer (about 20 g of alcohol) for 30 consecutive days. The CG volunteers consumed mineral water instead of beer. Blood samples were collected from EG and CG patients before and after the experiment. Albumin (Alb), globulin (Glo), and methanol-precipitable proteins (MPP) from human serum were denatured with 8 M urea. Fluorescence and electrophoresis were employed in order to elucidate urea-induced conformational changes and structural behavior of proteins. The measured fluorescence emission spectra were used to estimate the stability of native and denatured protein fractions before and after BC. It was found that before BC the fractions most stable to urea denaturation were Glo, Alb, and MPP fractions. After BC in most of the beer-consuming patients (EG) some changes in native and denatured protein fractions were detected: a tendency to lower stability and minor structural deviations. These qualitative changes were more profound in MPP than in Alb and Glo. Thus, Glo is more resistible to alcohol influence than Alb, which in turn is more resistible than MPP. No serum protein changes were detected in patients of CG.

Beer↗
PubMed2000

Intrinsic tryptophan fluorescence of human serum proteins and related conformational changes.

The unfolding of human serum proteins (HSP) was studied by measuring the intrinsic fluorescence intensity at a wavelength of excitation corresponding to tryptophan's or typosine's fluorescence and surface hydrophobicity. The maxima emission wavelengths (lambdamax) of human serum albumin (HSA) and human serum globulin (HSG) before beer consumption (BC) were 336.0 and 337.0 nm and after BC shifted to 335.0 and 334.0 nm, respectively. The surface hydrophobicity slightly increased after BC. In a solution of 8 M urea the lambdamax of BSA shifted to 346.4 and that of BSG to 342.5 nm. In contrast, in the same solution but after BC the lambdamax positions of HSA and HSG shifted to 355.9 and 357.7 nm, respectively. A decrease in fluorescence intensity, a shift in the maximum of emission, and an increase in surface hydrophobicity which reflected unfolding of proteins were observed. Here we provide evidence that the loosening of the HSP structure takes place primarily in various concentrations of urea before and after beer consumption. Differences in the fluorescence behavior of the proteins are attributed to disruption of the structure of proteins by denaturants as well as by the change in their compactability as a result of ethanol consumption.

Albumins↗
PubMed2000

Incidence of childhood type 1 diabetes worldwide. Diabetes Mondiale (DiaMond) Project Group.

OBJECTIVE: To investigate and monitor the patterns in incidence of childhood type 1 diabetes worldwide. RESEARCH DESIGN AND METHODS: The incidence of type 1 diabetes (per 100,000 per year) from 1990 to 1994 was determined in children < or =14 years of age from 100 centers in 50 countries. A total of 19,164 cases were diagnosed in study populations totaling 75.1 million children. The annual incidence rates were calculated per 100,000 population. RESULTS: The overall age-adjusted incidence of type 1 diabetes varied from 0.1/100,000 per year in China and Venezuela to 36.8/100,000 per year in Sardinia and 36.5/100,000 per year in Finland. This represents a >350-fold variation in the incidence among the 100 populations worldwide. The global pattern of variation in incidence was evaluated by arbitrarily grouping the populations with a very low (<1/100,000 per year), a low (1-4.99/100,000 per year), an intermediate (5-9.99/100,000 per year), a high (10-19.99/100,000 per year), and a very high (> or =20/100,000 per year) incidence. Of the European populations, 18 of 39 had an intermediate incidence, and the remainder had a high or very high incidence. A very high incidence (> or =20/ 100,000 per year) was found in Sardinia, Finland, Sweden, Norway Portugal, the U.K., Canada, and New Zealand. The lowest incidence (<1/100,000 per year) was found in the populations from China and South America. In most populations, the incidence increased with age and was the highest among children 10-14 years of age. CONCLUSIONS: The range of global variation in the incidence of childhood type 1 diabetes is even larger than previously described. The earlier reported polar-equatorial gradient in the incidence does not seem to be as strong as previously assumed, but the variation seems to follow ethnic and racial distribution in the world population.

Adolescent↗
PubMed1999

Type II diabetes mellitus: no longer just adults.

Type II diabetes mellitus is no longer exclusively a disease of adults. Health care professionals and agencies must gain a better understanding of (1) the epidemiology of type II diabetes mellitus in childhood; (2) the phenotypic, biochemical, metabolic, and autoimmune characteristics at diagnosis and during the course of the disease; (3) therapeutic modalities; (4) screening of high-risk populations; and (5) prevention strategies. This will be one of the challenges in pediatric diabetes as we approach the 21st century.

Adolescent↗
PubMed1998

Effect of beer consumption on plasma magnesium: randomized comparison with mineral water.

Moderate consumption of ethanol lowers mortality from coronary artery disease, and one of the possible mechanisms is an antiarrhythmic action. We therefore investigated the effect of a small daily dose of beer on plasma electrolytes. 52 men who seldom drank alcohol, clinically stable more than one year after coronary bypass surgery, were randomized to drink either 330 mL beer (containing about 20 g ethanol) or mineral water with similar potassium, magnesium, calcium and sodium content daily for 30 days. Plasma electrolytes and liver function indices, and also heart rate, blood pressure and weight, were measured before and after the trial period. The only significant before-and-after difference was in the group consuming beer, whose plasma magnesium rose from 0.89 (SD 0.01) to 0.98 (SD 0.02) mmol/L (P < 0.0025). This level of beer consumption did no obvious harm to liver function and its possibly beneficial effect on plasma magnesium deserves further investigation.

Aged↗
PubMed1997

Moderate beer consumption and positive biochemical changes in patients with coronary atherosclerosis.

OBJECTIVES: The aim of this study was to evaluate the influence of moderate beer consumption on lipid metabolism and antioxidant activity in patients (pts) with coronary artery disease (CAD). SUBJECTS: Forty-eight male pts with CAD not alcohol beverages consumers were randomly divided into experimental (EG) and control (CG) groups, 24 pts each. SETTING: Rehovot University Hospital, Israel. INTERVENTION: Every patient of the EG during a period of 30 consecutive days consumed 330 ml of Maccabee beer (> 20 g of alcohol). The pts of the CG did not consume alcohol during the trial period. METHODS: A wide range of tests including total cholesterol, LDL-C, HDL-C, total tocopherol and alpha-tocopherol. RESULTS: Only in the pts of the EG were found a tendency to an increase of the level of HDL-C and a statistically significant rise in the level of total tocopherol (P < 0.025) and alpha-tocopherol (P < 0.025). CONCLUSIONS: Even a short period of moderate beer consumption leads to some favourable biochemical changes in blood of pts with CAD which are widely regarded as indicators of CAD prevention.

Alcohol Drinking↗
PubMed1997

Moderate beer consumption and the blood coagulation in patients with coronary artery disease.

OBJECTIVES: To evaluate the influence of a short period of moderate beer consumption on the status of the thrombolitic activity in patients with coronary artery disease (CAD). SUBJECTS AND DESIGN: From 28 patients with two- or three-vessel CAD 22 were randomly assigned to an experimental group (EG) and six to control group (CG). Before and after completion of the study every one of the 28 patients was examined and a wide range of laboratory tests was performed. SETTING: A University Hospital in Israel. INTERVENTION: Of the EG, 22 patients consumed 330 mL of beer day-1 (20 g of alcohol) for the 30-day period in addition to the usual antiatherosclerotic diet. Patients of the CG did not consume alcohol beverages. MAIN OUTCOME MEASURES: Fibrinogen, prothrombin time (PT), coagulant activity of Factor VII (F VIIc) and Factor VII antigen (F VIIag), and plasminogen activator inhibitor (PAI) levels were studied. RESULTS: After the investigation a statistically significant decrease was found in F VIIc (P < 0.01) and F VIIag (P < 0.001) and to a lesser extent a decrease in the value of PAI. Fibrinogen and PT remained unchanged in the EG also. CONCLUSIONS: Even a short period of moderate beer consumption results in a decrease in thrombogenic activity. The only sensitive tests were F VIIc and F VIIag. The decrease in thrombogenic activity may be the main cause of decreased mortality in patients with CAD who consume moderate quantities of alcoholic beverages.

Aged↗
PubMed1996

Global epidemiology and public health in the 21st century. Applications of new technology.

Epidemiology and public health need to change for the upcoming problems of the 21st century and beyond. We outline a four-point approach to produce this change. The first one is to take a systems approach to disease. The second approach discussed is the use of new techniques to "count" disease using capture-recapture. The third represents the application of telecommunications, especially the Internet, to public health. The fourth and final component represents the application, at the local health department level, of a total quality approach, as espoused by Deming, for the prevention of disease.

Computer Communication Networks↗
PubMed1994

Diabetes in the Americas.

Diabetes mellitus is an important cause of disability and death throughout the Americas. Of the three main types (insulin-dependent, noninsulin-dependent, and malnutrition-related), virtually all cases in the Americas are either insulin-dependent (generally assessed in terms of incidence and usually occurring in subjects under 30) or noninsulin-dependent (generally assessed in terms of prevalence and usually occurring in subjects over 30). Data on noninsulin-dependent diabetes mellitus (NIDDM) in various parts of the Americas point to prevalences ranging from 1.4% (among the Mapuche Indians in Chile) to 14.1% (among residents of Mexico City). However, the use of different methods and standards to gather and analyze these data renders comparison of the NIDDM situations in different countries uncertain. A fair amount of comparable data on insulin-dependent diabetes mellitus (IDDM) have been gathered in various countries of the Region. These point to marked differences in annual incidence--ranging from 0.7 cases per 100,000 in Peru to 27 among males on Prince Edward Island, Canada--that have not been adequately explained, underlining the need for additional comparable data. Considering the seriousness of the disease, it is important to know how many people have and develop diabetes, so as to be able to take preventive and therapeutic measures and guide public health actions. Hence, further cooperation directed at effective standardization of procedures and goals is indicated. Such cooperation, which should also come to include standardized national and hemispheric diabetes programs, must be achieved in accordance with the resources available to each country.

Americas↗
PubMed1993

A review of the recent epidemiological data on the worldwide incidence of type 1 (insulin-dependent) diabetes mellitus. World Health Organization DIAMOND Project Group.

Nearly 70 registries from more than 40 countries have collected and published incidence data of childhood Type 1 (insulin-dependent) diabetes mellitus up to the end of the 1980s. The majority of incidence data comes from regions of high incidence i.e. from Europe and North America. All these published data facilitate the descriptive comparison of incidence and variation of the occurrence of Type 1 diabetes roughly throughout the northern hemisphere. The aim of this paper is to review and compare the most recent epidemiology data on the incidence of Type 1 diabetes among children under the age of 15 years. A clear difference in incidence appeared between northern and southern hemisphere with no countries below the equator having an incidence greater than 15.0 per 100,000. In contrast above the equator the disease is common. Between continents the variation in incidence showed that the lowest incidences were found in Asia, followed by Oceania (Australia and New Zealand), South and North America, and the highest rates were in Europe. The incidence varied from 0.6 per 100,000 in Korea and Mexico to 35.3 per 100,000 in Finland showing prominent worldwide variation in incidence of Type 1 diabetes. The largest intracontinental variation in incidence appeared in Europe, varying from the highest in Finland to the lowest (4.6 per 100,000) in northern Greece. The highest incidence in the world was in northern Europe, but within the continent scale there were some striking exceptions from the overall level of incidence.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Progressive multifocal leukoencephalopathy with gray matter involvement.

An unusual case of Progressive Multifocal Leukoencephalopathy (PML) in a Haitian man with AIDS is reported. The lesions involving both white and gray matter are described radiologically and at post-mortem. The implications regarding neuroradiological differential diagnosis in AIDS as well as PML virulence in this type of patient are discussed.

Acquired Immunodeficiency Syndrome↗