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Biomedical subjects

D Forman

Publications and source records attributed to D Forman.

187 records · Page 11Linked to original sources
PubMedDate not supplied

Cancer near nuclear installations.

The OPCS report on cancer incidence and mortality in the vicinity of nuclear installations in England and Wales provides a mass of information that is so large that it should be possible to detect quite small changes in disease levels with considerable confidence. The data on cancer mortality are less subject to selective bias than the registration data on which incidence rates are based, and they provide the firmest grounds on which evidence of any effect can be obtained. These data show conclusively that there has been no general increase in cancer mortality in the vicinity of nuclear installations in a 22-year period beginning several years after the opening of the installations that have released the largest amounts of radionuclides to the environment. On the contrary, the mortality from cancer has tended to be lower in the LAAs in the vicinity of nuclear installations than in control LAAs selected for their presumed comparability with the former. This is unlikely to be due to a protective effect of ionizing radiation and suggests that, despite the efforts that were made to choose comparable control areas, there were non-installation differences between the populations relevant to the risk of dying from one or other type of cancer. Detailed examination of the few types of cancer that were relatively more common in the installation areas suggest that several of the differences were most likely to be due to chance, diagnostic artefacts or social factors rather than to any hazard specifically related to the installations. One disease provides a possible exception: namely, leukaemia in the age group 0-24 years. Two other diseases need further investigation, multiple myeloma and Hodgkin's disease in the older age group 25-74 years. The excess mortality rates recorded from these cancers were not large, and it has yet to be established that they are not due to general confounding by other environmental or socio-economic factors.

Age Factors↗
PubMedDate not supplied

Significant endogenous synthesis of nitrate does not appear to be a feature of influenza A virus infection.

There is much concern about the role of nitrate in the formation of carcinogenic N-nitroso compounds. There has been renewed interest in the endogenous formation of nitrate arising as a host response to infection. This study was designed to investigate whether the large increases in nitrate excretion rate reported (6-15-fold) for certain infectious diseases is also a feature of systemic influenza infections. Volunteers were challenged either with an attenuated strain of influenza A virus or with saline; and excreted nitrate was measured in subsequent 24-h urine samples. Both with and without adjustment for potential confounding by dietary and other factors, it was clear that neither mild nor moderate influenza A virus infection resulted in substantial endogenous nitrate biosynthesis since all the variation in urinary nitrate excretion observed was within the range of normal daily fluctuations. It remains possible that a stronger and more consistent nitrate excretion response might be observed in other infectious illnesses with greater systemic disturbance.

Adult↗
PubMedDate not supplied

Risk factors for stomach cancer in sixty-five Chinese counties.

Stomach cancer mortality data were compared with dietary and biochemical data from 65 Chinese counties to provide clues to reasons for the marked geographic variation of stomach cancer mortality rates in China. Sex-specific correlation and multivariate regression analyses showed significant positive associations with consumption of salted vegetables and eggs, prevalence of antibodies to Helicobacter pylori, and levels of plasma albumin; and significant negative associations with intake of green vegetables and levels of plasma selenium and beta-carotene. Limitations of ecological data preclude causal inferences, but these findings suggest factors that may contribute to making stomach cancer the leading cause of cancer death in China and other countries.

Adult↗
PubMedDate not supplied

Plasma pepsinogens, nutrients, and diet in areas of Italy at varying gastric cancer risk.

In a survey of 930 adults aged 35-74 years randomly sampled from the general population of four areas of Italy at different risks for gastric cancer (GC), plasma levels of pepsinogens (PGI and PGII) and fat-soluble vitamins were assayed. Pepsinogen levels were used to identify individuals with chronic atrophic gastritis (CAG). Severe CAG (PGI < or = 20 pg/liter) affected 5.8% of the population, but the prevalence rose with increasing age and declining social class. Severe CAG was 5 times more common in areas with high compared to low rates of GC. Risk also rose with increasing consumption of salted/dried fish but was inversely related to dietary intake of beta-carotene and to plasma retinol and cholesterol levels. The prevalence of moderate CAG (PGI > 20 pg/liter, but PGI/PGII < or = 2.9) was 6.3%. Moderate CAG was also related to age and social class and increased 1.8-fold in areas where GC rates were high, but was not strongly associated with diet or plasma nutrients. The authors discuss these findings in relation to those from a previous case-control study of GC in the same areas.

Adult↗
PubMedDate not supplied

Helicobacter pylori antibodies in areas of Italy at varying gastric cancer risk.

In a survey of 930 adults aged 35-74 years randomly sampled from the general population of four areas of Italy, two at low and two at high risk for gastric cancer, plasma levels of Helicobacter pylori IgG antibodies were assayed in order to investigate associations with the geographical distribution of gastric cancer and other dietary and life-style factors, as assessed by personal interview. H. pylori positivity (antibody titer above or equal to 10 micrograms/ml), 45% overall, increased with age and was inversely associated with social class but showed little geographical variation or association with dietary variables and blood nutrients. H. pylori positivity was also associated with increased blood levels of pepsinogens, particularly pepsinogen II. The authors discuss these findings in relation to those from a previous case-control study of gastric cancer in the same areas.

Adult↗
PubMedDate not supplied

Serum anti-Helicobacter pylori IgG antibodies and pepsinogens A and C as serological markers of chronic atrophic gastritis.

This study was designed to test the sensitivity and specificity of serum anti-Helicobacter pylori IgG antibodies and the ratio of serum pepsinogen A to pepsinogen C (PGA:PGC) in detecting chronic atrophic gastritis (CAG) and intestinal metaplasia. Parallel gastric biopsies and a serum sample were collected from a series of 87 patients aged 20-69 years attending a routine upper endoscopy clinic. The seroprevalence (> 10 micrograms IgG/ml) of anti-H. pylori antibodies was 42.7%, and of a low PGA:PGC ratio (< 1.5) was 17.7%. A positive H. pylori IgG antibody level was more sensitive than the level of PGA:PGC in diagnosing CAG (71.4% and 25.0%, respectively), moderate CAG (86.7% and 26.7%, respectively), and intestinal metaplasia (90.9% and 50.0%, respectively). Anti-H. pylori IgG antibody levels were less specific than PGA:PGC levels in diagnosing CAG (90.9% and 93.9%, respectively), moderate CAG (78.3% and 89.1%, respectively), and intestinal metaplasia (72.6% and 92.2%, respectively). A combination of anti-H. pylori antibodies and a low PGA:PGC ratio for the detection of CAG resulted in a specificity of 100%, but the sensitivity was 21.4%.

Adult↗