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Biomedical subjects

A Hatzakis

Publications and source records attributed to A Hatzakis.

At least 109 records · Page 6Linked to original sources
PubMed1987

Delta agent and the etiology of hepatocellular carcinoma.

Sera from 87 patients with hepatitis B surface antigen (HBsAg)-positive hepatocellular carcinoma (HCC) and from 29 HBsAg-positive hospital controls were tested for delta (delta) antigen with an immunoenzymatic procedure and for anti-delta antibody, hepatitis Be antigen (HBeAg) and antibody to HBeAg (anti-HBe) by radioimmunoassay. All the sera, from both the HCC cases and the control patients, were negative for delta-antigen. Among the HCC cases 9 were positive for serum anti-delta (10%) whereas among the controls none was positive for this antibody (p = 0.067); the anti-delta-positive cases were found only among HCC patients negative for HBeAg. The lower prevalence of anti-delta among HBsAg-positive HCC patients, as compared to the corresponding prevalence among HBsAg-positive patients with chronic active hepatitis or cirrhosis (reported in the literature) indicates that the pathogenesis of HCC is frequently independent of the pathogenesis of the other HBsAg-positive common chronic liver diseases. By contrast, the higher prevalence of anti-delta among HBsAg-positive HCC cases than among HBsAg-positive controls may reflect the longer average duration of the carrier state in HCC patients (until integration is accomplished and the induction period completed). Serum HBeAg was higher among HBsAg-positive HCC patients with cirrhosis (23%) than among HBsAg-positive HCC patients without cirrhosis (6%) or HBsAg-positive controls (3%); thus, the conflicting results in the literature concerning the association of the HBeAg/anti-HBe system with HCC may be accounted for, in part, by the variable association of HCC with an underlying cirrhosis.

Carcinoma, Hepatocellular↗
PubMed1987

Time trends of tobacco smoking, air pollution, and lung cancer in Athens.

Athens is a city with a serious air pollution problem which has existed for more than 20 years. To evaluate whether air pollution has affected lung cancer incidence (and hence, mortality) in the population of Athens we have compared standardized lung mortality between Athens and the rest of Greece taking into account the tobacco consumption trends in the respective populations and varying the postulated latency between 0 and 20 years. There is no evidence for an independent or interactive (with tobacco smoking) effect of air pollution on lung cancer mortality; the tobacco-adjusted mortality appears, if anything, lower in Athens than in the rest of Greece and the slopes of lung cancer mortality on tobacco consumption are almost identical in Athens and in the rest of Greece. By contrast, the same data are compatible with a strong effect of tobacco smoking on lung cancer mortality, an effect which appears to involve not only the early carcinogenic stages but also some of the later ones. The results of the present analysis do not support the hypothesis that air pollution, at least in Athens until 1980, has increased the incidence of lung cancer to an extent large enough to be detectable in ecological correlation analyses. Nevertheless the inherent limitations of these methods indicate that their results should be interpreted with caution and only as a step toward the gradual understanding of a complex issue.

Air Pollution↗
PubMed1987

Opportunistic malignancies and the acquired immunodeficiency syndrome.

The clinical manifestations of chronic infection with the Human Immunodeficiency Virus (HIV) fall into two broad categories: opportunistic infections and opportunistic malignancies. The initial observation of both occurring in outbreak fashion among young homosexual men led to the early identification of the present pandemic. Conversely, the identification of additional malignancies which occur in excess frequency in the presence of the immunodeficiency of HIV infection can provide insight into the role of viruses in human malignancy. The first report related to the acquired immunodeficiency syndrome (AIDS) epidemic was of a series of 5 cases of Pneumocystic carinii in young homosexual men in Los Angeles and was published in June 1981. This was shortly followed by the report of additional cases of P. carinii as well as Kaposi's sarcoma (KS) occurring among young homosexual men in California and New York City. The increased risk of KS among people with HIV infection has been confirmed since these initial reports, with 1 in 5 AIDS patients in the United States developing KS sometime in their course of disease. However, the proportion of AIDS patients with KS has decreased from 35% before 1983 to 15% in the first half of 1987. Among the recognized risk groups of AIDS patients, the proportion with KS is highest among homosexual men and female intravenous drug abusers, and lowest among children and hemophiliacs. This variation suggests that risk of KS in AIDS parallels that of sexually-transmitted infections. A second family of opportunistic malignancy in AIDS is comprised of the non-Hodgkin's disease lymphomas (NHL). These lymphomas are typically of B-cell origin, immunoblastic or Burkitt's-like in character, and frequently present with extra-nodal involvement such as the central nervous system. These were first recognized somewhat later than KS as being associated with AIDS; together, KS and NHL account for about 95% of all neoplasms seen in AIDS patients. Additional malignancies are currently suspected to occur excessively with HIV infection. These include Hodgkin's disease, anorectal carcinoma, and testicular cancer. Validation of these associations will require extensive epidemiologic surveillance. Since HIV infection leads to progressive loss of cellular immunity, it is probable that these malignancies result from the progressive reactivation or loss of immunologic control of latent oncogenic viruses. The cytomegalovirus has been implicated in the pathogenesis of KS, perhaps with reinfection, and the Epstein-Barr virus in the NHL. The role of papilloma viruses in anorectal carcinoma has also been proposed.(ABSTRACT TRUNCATED AT 400 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1986

Short-term effects of air pollution on mortality in Athens.

Short-term effects of air pollution on mortality in Athens during the years 1975-1982 were studied. Daily values of sulphur dioxide (SO2) and smoke, measured by a five-station network of the National Observatory of Athens, were used as air pollution indicators. Mortality data were abstracted from the Town Registries of Athens and 18 other contiguous towns within the Greater Athens area. It was found that the adjusted daily mortality (estimated by subtracting from the observed value of mortality an 'expected' value, calculated after fitting a sinusoid curve to the empirical mortality data) depends positively and significantly on the level of SO2 (b = +0.0058, p = 0.05). This relation is independent of temperature, relative humidity, secular, seasonal, monthly and weekly variations of mortality as well as of synergistic effects of the above variables with season. No relation was found between smoke and adjusted daily mortality. An analysis for the determination of a possible threshold in the levels of SO2 causing health effects was also undertaken, by studying changes in the SO2 regression coefficients after successive deletion from the regression model of the days with the highest SO2 values. Our study shows that if there is an SO2 threshold it must lie slightly below the level of 150 micrograms/m3 (mean daily value).

Air Pollutants↗
PubMed1984

Sex-related differences in immunoglobulin M and in total antibody response to hepatitis A virus observed in two epidemics of hepatitis A.

Sixty symptomatic and 42 asymptomatic cases of hepatitis A detected during two epidemics on the Greek island of Crete in autumn-winter, 1978-1979 were tested for serum total and immunoglobulin M (IgM) specific antibody to hepatitis A virus (anti-HAV and IgM anti-HAV) by commercially available solid phase radioimmunoassays. All cases of symptomatic hepatitis A tested during the first eight weeks from onset were IgM anti-HAV positive with a geometric mean titer of 1:3,575 at 0-28 days from onset. The probability of positivity declined progressively thereafter: a 50% level was reached on the 128th day from onset and the geometric mean titer dropped to 1:317 in samples obtained after the 85th day from onset. Asymptomatic patients had a significantly shorter duration of IgM response than symptomatic ones and three months from onset the prevalence of IgM anti-HAV was only 33% in the former compared to 95% in the latter (p less than 0.0001). A significantly higher prevalence of IgM anti-HAV and higher titers of total and IgM specific anti-HAV was observed in females than in males. IgM anti-HAV was positive in 12 (57%) of 21 samples from females compared to three (12.5%) of 24 samples from males, collected after the 85th day from onset (p less than 0.01). Five months from onset, the cumulative probability of IgM anti-HAV positivity in females was 38% compared to 0% in males (p less than 0.05).

Antibody Formation↗
PubMedDate not supplied

Effects of lead on the somatic growth of children.

Studies on the effects of lead on the somatic growth of children are limited and contradictory. The authors investigated the adverse effects of blood lead concentration on the somatic growth of primary-school-age children. In this study, there was a total of 522 children, aged 6-9 y, who resided in three areas of Greece (i.e., Loutraki, Lavrion, and Elefsina). The medical evaluation included medical history; physical examination; and measurements of height, head circumference, and chest circumference. The authors also evaluated dietary information, socioeconomic status, and height of parents. The authors conducted laboratory tests for hematological parameters and blood lead levels. The mean blood lead level was 12.3 microg/dl (standard deviation = 8.9 microg/dl), and levels ranged from 1.3 microg/dl to 51.2 microg/dl. There were negative monotonic relationships between growth parameters and blood lead levels, even after the authors allowed for confounding effects. An increase in blood lead level of 10 microg/dl was associated with a decrease of (a) 0.33 cm in head circumference (95% confidence interval = 0.12, 0.55; p = .002); (b) 0.86 cm in height (95% confidence interval = 0.14, 1.16; p = .020); and (c) 0.40 cm in chest circumference (95% confidence interval = -0.22, 1.02; p = .207). These findings led the authors to conclude that a decrease in growth in children may be associated with blood lead concentrations.

Anthropometry↗
PubMedDate not supplied

Virological and immunological response to HAART therapy in a community-based cohort of HIV-1-positive individuals.

PURPOSE: To determine virological and immunological response to highly active antiretroviral therapy (HAART) and to investigate factors influencing response in a community-based setting. METHOD: Plasma HIV RNA levels and CD4 cell counts were studied in 168 unselected individuals starting HAART including indinavir or ritonavir or hard-gel saquinavir-containing regimens. RESULTS: Overall, 60% of the patients reduced their HIV RNA to below 500 Eq/mL, but half of them experienced a subsequent virologic rebound. Patients with higher baseline HIV RNA, higher baseline CD4 cell count, and simultaneous initiation of combination therapy and patients on indinavir or ritonavir regimen were more likely to have virologic response within 6 months since HAART initiation. Patients with lower baseline CD4 cell count and with lower rates of viral clearance had a higher probability of a subsequent virologic rebound. Forty percent of the patients had increased their CD4 cell counts by more than 100 cells/microL (immunologic response). The probability of immunologic response was independent of baseline HIV RNA levels and CD4 cell count; however, the more complete the virologic suppression, the higher the probability of immunologic response. Thirty percent of the patients had discordance between virologic and immunologic responses. CONCLUSION: The rate of virologic failure in this unselected group of patients was higher than that observed in randomized clinical trials, but only a minority (11%) of the patients were treatment naïve. Starting combination therapy simultaneously and initiating antiretroviral therapy before advanced HIV disease has developed predict virologic response, whereas the magnitude of viral suppression predicts mid to long immunological response.

Adult↗
PubMedDate not supplied

Molecular epidemiology of vertical human immunodeficiency virus type 1 transmission in Greece: evidence of non-B subtypes.

OBJECTIVES: To investigate the subtype classification of the circulating virus strains among human immunodeficiency virus type 1 (HIV-1)-infected children in Greece. STUDY DESIGN/METHODS: Since the beginning of the acquired immunodeficiency syndrome (AIDS) epidemic in Greece in 1982, 23 children have been reported to be vertically infected with HIV-1. Blood samples were available for 19 of these children, and the C2-C4 env region was successfully amplified by nested polymerase chain reaction (PCR) for 16 subjects. HIV-1 subtype was established by the heteroduplex mobility assay (HMA) in 16 subjects and confirmed by DNA sequencing and phylogenetic analysis in 8 subjects. RESULTS: Most subjects (9; 56%) fell into subtype B. However, a substantial proportion (44%) were classified as subtypes A (3; 19%), C (1; 6%), D (1; 6%), and I (2; 12%). According to epidemiologic information, 5 of 7 children infected with non-B HIV-1 subtypes were born to Greek parents. CONCLUSION: These findings clearly suggest that non-B strains have been introduced into Greece, providing evidence that HIV epidemic in this country will probably change profile over time. In addition, subtype I was identified in 2 HIV-1-infected children, both of whom were born to Greek parents.

Adolescent↗
PubMedDate not supplied

Total and cause-specific mortality in a population based cohort of diabetics in Greece.

Eleven years after a diabetes detection drive--conducted in a sample of 21,410 individuals--a follow-up study showed that 207 persons had died from a total of 489 previously known diabetics. Ten year survival rates were lower in male and female diabetics as compared to those observed in the general population. In addition it was shown that diabetic patients died more often from cardiovascular causes compared to sex and age matched samples of the general population (males 63.3% vs 44.3%; females 76.0% vs 51.7%). No mortality differences by the type of hypoglycaemic treatment were noted.

Age Factors↗
PubMedDate not supplied

Peripheral occlusive arterial disease in longstanding diabetes mellitus. A population study.

One hundred and seventy-five diabetic patients belonging to the same cohort were investigated. They were all inhabitants of a suburb of Athens and were initially identified during a diabetes detection drive conducted 11 years earlier. The study comprised a full physical examination, answering of a detailed questionnaire--with emphasis on signs of intermittent claudication (IC)--and a 12 lead ECG (analyzed according to the Minnesota code). It was shown that clinical signs of peripheral occlusive arterial disease were significantly associated to male sex, increased duration of diabetes, type of treatment and major ECG signs of coronary heart disease, while increased age, current smoking and existence ease, while increased age, current smoking and existence of hypertension were not significantly associated to POAD.

Arterial Occlusive Diseases↗